[3/5] PCI: cadence: Add host driver for Cadence PCIe controller

This patch adds support to the Cadence PCIe controller in host mode.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
---
 drivers/Makefile                        |   1 +
 drivers/pci/Kconfig                     |   1 +
 drivers/pci/cadence/Kconfig             |  24 ++
 drivers/pci/cadence/Makefile            |   2 +
 drivers/pci/cadence/pcie-cadence-host.c | 425 ++++++++++++++++++++++++++++++++
 drivers/pci/cadence/pcie-cadence.c      | 110 +++++++++
 drivers/pci/cadence/pcie-cadence.h      | 325 ++++++++++++++++++++++++
 7 files changed, 888 insertions(+)
 create mode 100644 drivers/pci/cadence/Kconfig
 create mode 100644 drivers/pci/cadence/Makefile
 create mode 100644 drivers/pci/cadence/pcie-cadence-host.c
 create mode 100644 drivers/pci/cadence/pcie-cadence.c
 create mode 100644 drivers/pci/cadence/pcie-cadence.h

On Thu, Nov 23, 2017 at 04:01:48PM +0100, Cyrille Pitchen wrote:
> This patch adds support to the Cadence PCIe controller in host mode.
> 
> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> ---
>  drivers/Makefile                        |   1 +
>  drivers/pci/Kconfig                     |   1 +
>  drivers/pci/cadence/Kconfig             |  24 ++
>  drivers/pci/cadence/Makefile            |   2 +
>  drivers/pci/cadence/pcie-cadence-host.c | 425 ++++++++++++++++++++++++++++++++
>  drivers/pci/cadence/pcie-cadence.c      | 110 +++++++++
>  drivers/pci/cadence/pcie-cadence.h      | 325 ++++++++++++++++++++++++
>  7 files changed, 888 insertions(+)
>  create mode 100644 drivers/pci/cadence/Kconfig
>  create mode 100644 drivers/pci/cadence/Makefile
>  create mode 100644 drivers/pci/cadence/pcie-cadence-host.c
>  create mode 100644 drivers/pci/cadence/pcie-cadence.c
>  create mode 100644 drivers/pci/cadence/pcie-cadence.h

I prefer a single file per driver.  I assume you're anticipating
something like dwc, where the DesignWare core is incorporated into
several devices in slightly different ways.  But it doesn't look like
that's here yet, and personally, I'd rather split out the required
things when they actually become required, not ahead of time.

> diff --git a/drivers/Makefile b/drivers/Makefile
> index 1d034b680431..27bdd98784d9 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -18,6 +18,7 @@ obj-y				+= pwm/
>  
>  obj-$(CONFIG_PCI)		+= pci/
>  obj-$(CONFIG_PCI_ENDPOINT)	+= pci/endpoint/
> +obj-$(CONFIG_PCI_CADENCE)	+= pci/cadence/

I can't remember why we added CONFIG_PCI_ENDPOINT here instead of in
drivers/pci/Makefile.  Is there any way to move both CONFIG_PCI_ENDPOINT
and CONFIG_PCI_CADENCE into drivers/pci/Makefile so this is better
encapsulated?

>  # PCI dwc controller drivers
>  obj-y				+= pci/dwc/
>...

> + * struct cdns_pcie_rc_data - hardware specific data

"cdns" is a weird abbreviation for "Cadence", since "Cadence" doesn't
contain an "s".

>...
> +static int cdns_pcie_parse_request_of_pci_ranges(struct device *dev,
> +						 struct list_head *resources,
> +						 struct resource **bus_range)
> +{
> +	int err, res_valid = 0;
> +	struct device_node *np = dev->of_node;
> +	resource_size_t iobase;
> +	struct resource_entry *win, *tmp;
> +
> +	err = of_pci_get_host_bridge_resources(np, 0, 0xff, resources, &iobase);
> +	if (err)
> +		return err;
> +
> +	err = devm_request_pci_bus_resources(dev, resources);
> +	if (err)
> +		return err;
> +
> +	resource_list_for_each_entry_safe(win, tmp, resources) {
> +		struct resource *res = win->res;
> +
> +		switch (resource_type(res)) {
> +		case IORESOURCE_IO:
> +			err = pci_remap_iospace(res, iobase);
> +			if (err) {
> +				dev_warn(dev, "error %d: failed to map resource %pR\n",
> +					 err, res);
> +				resource_list_destroy_entry(win);
> +			}
> +			break;
> +		case IORESOURCE_MEM:
> +			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
> +			break;
> +		case IORESOURCE_BUS:
> +			*bus_range = res;
> +			break;
> +		}
> +	}
> +
> +	if (res_valid)
> +		return 0;
> +
> +	dev_err(dev, "non-prefetchable memory resource required\n");
> +	return -EINVAL;
> +}

The code above is starting to look awfully familiar.  I wonder if it's
time to think about some PCI-internal interface that can encapsulate
this.  In this case, there's really nothing Cadence-specific here.
There are other callers where there *is* vendor-specific code, but
possibly that could be handled by returning pointers to bus number,
I/O port, and MMIO resources so the caller could do the
vendor-specific stuff?

Bjorn

On Tue, Nov 28, 2017 at 02:41:14PM -0600, Bjorn Helgaas wrote:
> On Thu, Nov 23, 2017 at 04:01:48PM +0100, Cyrille Pitchen wrote:
> > diff --git a/drivers/Makefile b/drivers/Makefile
> > index 1d034b680431..27bdd98784d9 100644
> > --- a/drivers/Makefile
> > +++ b/drivers/Makefile
> > @@ -18,6 +18,7 @@ obj-y				+= pwm/
> >  
> >  obj-$(CONFIG_PCI)		+= pci/
> >  obj-$(CONFIG_PCI_ENDPOINT)	+= pci/endpoint/
> > +obj-$(CONFIG_PCI_CADENCE)	+= pci/cadence/
> 
> I can't remember why we added CONFIG_PCI_ENDPOINT here instead of in
> drivers/pci/Makefile.  Is there any way to move both CONFIG_PCI_ENDPOINT
> and CONFIG_PCI_CADENCE into drivers/pci/Makefile so this is better
> encapsulated?

I now see the note in your cover letter.  If there is a reason for
this, it should go in the changelog to forestall questions like this.
But what's in the cover letter isn't quite enough because it doesn't
answer the question of why drivers/pci/Makefile isn't sufficient to
control the ordering of pci/dwc and pci/endpoint.

And sorry, I now see Lorenzo's similar query so he's already jumped on
this :)

> >  # PCI dwc controller drivers
> >  obj-y				+= pci/dwc/

Hello,

On Tue, 28 Nov 2017 14:41:14 -0600, Bjorn Helgaas wrote:

> > + * struct cdns_pcie_rc_data - hardware specific data  
> 
> "cdns" is a weird abbreviation for "Cadence", since "Cadence" doesn't
> contain an "s".

cdns is the official Device Tree binding vendor prefix for Cadence:

$ grep Cadence Documentation/devicetree/bindings/vendor-prefixes.txt
cdns	Cadence Design Systems Inc.

And it is already widely used throughout the kernel for Cadence
drivers. See drivers/watchdog/cadence_wdt.c, drivers/spi/spi-cadence.c,
drivers/i2c/busses/i2c-cadence.c, etc.

Best regards,

Thomas Petazzoni

On Tue, Nov 28, 2017 at 02:41:14PM -0600, Bjorn Helgaas wrote:

[...]

> > +static int cdns_pcie_parse_request_of_pci_ranges(struct device *dev,
> > +						 struct list_head *resources,
> > +						 struct resource **bus_range)
> > +{
> > +	int err, res_valid = 0;
> > +	struct device_node *np = dev->of_node;
> > +	resource_size_t iobase;
> > +	struct resource_entry *win, *tmp;
> > +
> > +	err = of_pci_get_host_bridge_resources(np, 0, 0xff, resources, &iobase);
> > +	if (err)
> > +		return err;
> > +
> > +	err = devm_request_pci_bus_resources(dev, resources);
> > +	if (err)
> > +		return err;
> > +
> > +	resource_list_for_each_entry_safe(win, tmp, resources) {
> > +		struct resource *res = win->res;
> > +
> > +		switch (resource_type(res)) {
> > +		case IORESOURCE_IO:
> > +			err = pci_remap_iospace(res, iobase);
> > +			if (err) {
> > +				dev_warn(dev, "error %d: failed to map resource %pR\n",
> > +					 err, res);
> > +				resource_list_destroy_entry(win);
> > +			}
> > +			break;
> > +		case IORESOURCE_MEM:
> > +			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
> > +			break;
> > +		case IORESOURCE_BUS:
> > +			*bus_range = res;
> > +			break;
> > +		}
> > +	}
> > +
> > +	if (res_valid)
> > +		return 0;
> > +
> > +	dev_err(dev, "non-prefetchable memory resource required\n");
> > +	return -EINVAL;
> > +}
> 
> The code above is starting to look awfully familiar.  I wonder if it's
> time to think about some PCI-internal interface that can encapsulate
> this.  In this case, there's really nothing Cadence-specific here.
> There are other callers where there *is* vendor-specific code, but
> possibly that could be handled by returning pointers to bus number,
> I/O port, and MMIO resources so the caller could do the
> vendor-specific stuff?

Yes and that's not the only one, pattern below is duplicated
(with some minor differences across host bridges that I think
can be managed through function parameters), it is probably worth
moving them both into a core code helper.

list_splice_init(&resources, &bridge->windows);
bridge->dev.parent = dev;
bridge->busnr = bus;
bridge->ops = &pci_ops;
bridge->map_irq = of_irq_parse_and_map_pci;
bridge->swizzle_irq = pci_common_swizzle;

ret = pci_scan_root_bus_bridge(bridge);
if (ret < 0) {
	dev_err(dev, "Scanning root bridge failed");
	goto err_init;
}

bus = bridge->bus;
pci_bus_size_bridges(bus);
pci_bus_assign_resources(bus);

list_for_each_entry(child, &bus->children, node)
	pcie_bus_configure_settings(child);

pci_bus_add_devices(bus);

On Wed, Nov 29, 2017 at 09:19:29AM +0100, Thomas Petazzoni wrote:
> Hello,
> 
> On Tue, 28 Nov 2017 14:41:14 -0600, Bjorn Helgaas wrote:
> 
> > > + * struct cdns_pcie_rc_data - hardware specific data  
> > 
> > "cdns" is a weird abbreviation for "Cadence", since "Cadence" doesn't
> > contain an "s".
> 
> cdns is the official Device Tree binding vendor prefix for Cadence:
> 
> $ grep Cadence Documentation/devicetree/bindings/vendor-prefixes.txt
> cdns	Cadence Design Systems Inc.
> 
> And it is already widely used throughout the kernel for Cadence
> drivers. See drivers/watchdog/cadence_wdt.c, drivers/spi/spi-cadence.c,
> drivers/i2c/busses/i2c-cadence.c, etc.

Hard to argue with that!  Thanks!

On Thu, Nov 23, 2017 at 04:01:48PM +0100, Cyrille Pitchen wrote:
> This patch adds support to the Cadence PCIe controller in host mode.

Bjorn already commented on this, it would be good to add some
of the cover letter details in this log.

> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> ---
>  drivers/Makefile                        |   1 +
>  drivers/pci/Kconfig                     |   1 +
>  drivers/pci/cadence/Kconfig             |  24 ++
>  drivers/pci/cadence/Makefile            |   2 +
>  drivers/pci/cadence/pcie-cadence-host.c | 425 ++++++++++++++++++++++++++++++++

You should also update the MAINTAINERS file.

>  drivers/pci/cadence/pcie-cadence.c      | 110 +++++++++
>  drivers/pci/cadence/pcie-cadence.h      | 325 ++++++++++++++++++++++++
>  7 files changed, 888 insertions(+)
>  create mode 100644 drivers/pci/cadence/Kconfig
>  create mode 100644 drivers/pci/cadence/Makefile
>  create mode 100644 drivers/pci/cadence/pcie-cadence-host.c
>  create mode 100644 drivers/pci/cadence/pcie-cadence.c
>  create mode 100644 drivers/pci/cadence/pcie-cadence.h
>
> diff --git a/drivers/Makefile b/drivers/Makefile
> index 1d034b680431..27bdd98784d9 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -18,6 +18,7 @@ obj-y                               += pwm/
>
>  obj-$(CONFIG_PCI)            += pci/
>  obj-$(CONFIG_PCI_ENDPOINT)   += pci/endpoint/
> +obj-$(CONFIG_PCI_CADENCE)    += pci/cadence/

Already commented on the cover letter.

>  # PCI dwc controller drivers
>  obj-y                                += pci/dwc/
>
> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> index 90944667ccea..2471b2e36b8b 100644
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -144,6 +144,7 @@ config PCI_HYPERV
>            PCI devices from a PCI backend to support PCI driver domains.
>
>  source "drivers/pci/hotplug/Kconfig"
> +source "drivers/pci/cadence/Kconfig"
>  source "drivers/pci/dwc/Kconfig"
>  source "drivers/pci/host/Kconfig"
>  source "drivers/pci/endpoint/Kconfig"
> diff --git a/drivers/pci/cadence/Kconfig b/drivers/pci/cadence/Kconfig
> new file mode 100644
> index 000000000000..120306cae2aa
> --- /dev/null
> +++ b/drivers/pci/cadence/Kconfig
> @@ -0,0 +1,24 @@
> +menuconfig PCI_CADENCE
> +     bool "Cadence PCI controllers support"
> +     depends on PCI && HAS_IOMEM
> +     help
> +       Say Y here if you want to support some Cadence PCI controller.
> +
> +       When in doubt, say N.
> +
> +if PCI_CADENCE
> +
> +config PCIE_CADENCE
> +     bool
> +
> +config PCIE_CADENCE_HOST
> +     bool "Cadence PCIe host controller"
> +     depends on OF
> +     depends on PCI_MSI_IRQ_DOMAIN

I do not see the reason for this dependency in the code.

> +     select PCIE_CADENCE
> +     help
> +       Say Y here if you want to support the Cadence PCIe controller in host
> +       mode. This PCIe controller may be embedded into many different vendors
> +       SoCs.
> +
> +endif # PCI_CADENCE
> diff --git a/drivers/pci/cadence/Makefile b/drivers/pci/cadence/Makefile
> new file mode 100644
> index 000000000000..d57d192d2595
> --- /dev/null
> +++ b/drivers/pci/cadence/Makefile
> @@ -0,0 +1,2 @@
> +obj-$(CONFIG_PCIE_CADENCE) += pcie-cadence.o
> +obj-$(CONFIG_PCIE_CADENCE_HOST) += pcie-cadence-host.o
> diff --git a/drivers/pci/cadence/pcie-cadence-host.c b/drivers/pci/cadence/pcie-cadence-host.c
> new file mode 100644
> index 000000000000..252471e72a93
> --- /dev/null
> +++ b/drivers/pci/cadence/pcie-cadence-host.c
> @@ -0,0 +1,425 @@
> +/*
> + * Cadence PCIe host controller driver.
> + *
> + * Copyright (c) 2017 Cadence
> + *
> + * Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +#include <linux/kernel.h>
> +#include <linux/of_address.h>
> +#include <linux/of_pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +
> +#include "pcie-cadence.h"
> +
> +/**
> + * struct cdns_pcie_rc_data - hardware specific data
> + * @max_regions: maximum number of regions supported by the hardware
> + * @vendor_id: PCI vendor ID
> + * @device_id: PCI device ID
> + * @no_bar_nbits: Number of bits to keep for inbound (PCIe -> CPU) address
> + *                translation (nbits sets into the "no BAR match" register).
> + */
> +struct cdns_pcie_rc_data {
> +     size_t                  max_regions;

Reason for it to be size_t ?

> +     u16                     vendor_id;
> +     u16                     device_id;
> +     u8                      no_bar_nbits;
> +};

I think that this data should come from DT (?) more below.

> +
> +/**
> + * struct cdns_pcie_rc - private data for this PCIe Root Complex driver
> + * @pcie: Cadence PCIe controller
> + * @dev: pointer to PCIe device
> + * @cfg_res: start/end offsets in the physical system memory to map PCI
> + *           configuration space accesses
> + * @bus_range: first/last buses behind the PCIe host controller
> + * @cfg_base: IO mapped window to access the PCI configuration space of a
> + *            single function at a time
> + * @data: pointer to a 'struct cdns_pcie_rc_data'
> + */
> +struct cdns_pcie_rc {
> +     struct cdns_pcie        pcie;
> +     struct device           *dev;
> +     struct resource         *cfg_res;
> +     struct resource         *bus_range;
> +     void __iomem            *cfg_base;
> +     const struct cdns_pcie_rc_data  *data;
> +};
> +
> +static void __iomem *

Please do not split lines like this, storage class and return type
should be in the same line as the name, move parameter(s) to a new
line.

static void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
                                      int where)

> +cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn, int where)
> +{
> +     struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
> +     struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
> +     struct cdns_pcie *pcie = &rc->pcie;
> +     unsigned int busn = bus->number;
> +     u32 addr0, desc0;
> +
> +     if (busn < rc->bus_range->start || busn > rc->bus_range->end)
> +             return NULL;

It does not hurt but I wonder whether you really need this check.

> +     if (busn == rc->bus_range->start) {
> +             if (devfn)

I suspect I know why you need this check but I ask you to explain it
anyway if you do not mind please.

> +                     return NULL;
> +
> +             return pcie->reg_base + (where & 0xfff);
> +     }
> +
> +     /* Update Output registers for AXI region 0. */
> +     addr0 = CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(12) |

Ok, so for every config access you reprogram addr0 to reflect the
correct bus|devfn ID in the PCI bus TLP corresponding to an ECAM address
in CPU physical address space, is my understanding correct ?

> +             CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN(devfn) |
> +             CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS(busn);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(0), addr0);
> +
> +     /* Configuration Type 0 or Type 1 access. */
> +     desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
> +             CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
> +     /*
> +      * The bus number was already set once for all in desc1 by
> +      * cdns_pcie_host_init_address_translation().
> +      */
> +     if (busn == rc->bus_range->start + 1)
> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE0;
> +     else
> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE1;

I would like to ask you why you have to do it here and the root port
does not figure it out by itself, I do not have the datasheet so I am
just asking for my own information.

> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(0), desc0);
> +
> +     return rc->cfg_base + (where & 0xfff);
> +}
> +
> +static struct pci_ops cdns_pcie_host_ops = {
> +     .map_bus        = cdns_pci_map_bus,
> +     .read           = pci_generic_config_read,
> +     .write          = pci_generic_config_write,
> +};
> +
> +static const struct cdns_pcie_rc_data cdns_pcie_rc_data = {
> +     .max_regions    = 32,
> +     .vendor_id      = PCI_VENDOR_ID_CDNS,
> +     .device_id      = 0x0200,
> +     .no_bar_nbits   = 32,
> +};

Should (some of) these parameters be retrieved through a DT binding ?

> +static const struct of_device_id cdns_pcie_host_of_match[] = {
> +     { .compatible = "cdns,cdns-pcie-host",
> +       .data = &cdns_pcie_rc_data },
> +
> +     { },
> +};
> +
> +static int cdns_pcie_parse_request_of_pci_ranges(struct device *dev,
> +                                              struct list_head *resources,
> +                                              struct resource **bus_range)
> +{
> +     int err, res_valid = 0;
> +     struct device_node *np = dev->of_node;
> +     resource_size_t iobase;
> +     struct resource_entry *win, *tmp;
> +
> +     err = of_pci_get_host_bridge_resources(np, 0, 0xff, resources, &iobase);
> +     if (err)
> +             return err;
> +
> +     err = devm_request_pci_bus_resources(dev, resources);
> +     if (err)
> +             return err;
> +
> +     resource_list_for_each_entry_safe(win, tmp, resources) {
> +             struct resource *res = win->res;
> +
> +             switch (resource_type(res)) {
> +             case IORESOURCE_IO:
> +                     err = pci_remap_iospace(res, iobase);
> +                     if (err) {
> +                             dev_warn(dev, "error %d: failed to map resource %pR\n",
> +                                      err, res);
> +                             resource_list_destroy_entry(win);
> +                     }
> +                     break;
> +             case IORESOURCE_MEM:
> +                     res_valid |= !(res->flags & IORESOURCE_PREFETCH);
> +                     break;
> +             case IORESOURCE_BUS:
> +                     *bus_range = res;
> +                     break;
> +             }
> +     }
> +
> +     if (res_valid)
> +             return 0;
> +
> +     dev_err(dev, "non-prefetchable memory resource required\n");
> +     return -EINVAL;

Nit, I prefer you swap these two as it is done in pci-aardvark.c:

        if (!res_valid) {
                dev_err(dev, "non-prefetchable memory resource required\n");
                return -EINVAL;
        }

        return 0;

but as per previous replies this function can be factorized in
core PCI code - I would not bother unless you are willing to write
the patch series that does the refactoring yourself :)

> +}
> +
> +static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
> +{
> +     const struct cdns_pcie_rc_data *data = rc->data;
> +     struct cdns_pcie *pcie = &rc->pcie;
> +     u8 pbn, sbn, subn;
> +     u32 value, ctrl;
> +
> +     /*
> +      * Set the root complex BAR configuration register:
> +      * - disable both BAR0 and BAR1.
> +      * - enable Prefetchable Memory Base and Limit registers in type 1
> +      *   config space (64 bits).
> +      * - enable IO Base and Limit registers in type 1 config
> +      *   space (32 bits).
> +      */
> +     ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
> +     value = CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(ctrl) |
> +             CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(ctrl) |
> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE |
> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS |
> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE |
> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS;
> +     cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
> +
> +     /* Set root port configuration space */
> +     if (data->vendor_id != 0xffff)
> +             cdns_pcie_rp_writew(pcie, PCI_VENDOR_ID, data->vendor_id);
> +     if (data->device_id != 0xffff)
> +             cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, data->device_id);
> +
> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
> +     cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
> +
> +     pbn = rc->bus_range->start;
> +     sbn = pbn + 1; /* Single root port. */
> +     subn = rc->bus_range->end;
> +     cdns_pcie_rp_writeb(pcie, PCI_PRIMARY_BUS, pbn);
> +     cdns_pcie_rp_writeb(pcie, PCI_SECONDARY_BUS, sbn);
> +     cdns_pcie_rp_writeb(pcie, PCI_SUBORDINATE_BUS, subn);

Again - I do not have the datasheet for this device therefore I would
kindly ask you how this works; it seems to me that what you are doing
here is done through normal configuration cycles in an ECAM compliant
system to program the RP PRIMARY/SECONDARY/SUBORDINATE bus - I would
like to understand why this code is needed.

> +     return 0;
> +}
> +
> +static int cdns_pcie_host_init_address_translation(struct cdns_pcie_rc *rc)
> +{
> +     struct cdns_pcie *pcie = &rc->pcie;
> +     struct resource *cfg_res = rc->cfg_res;
> +     struct resource *mem_res = pcie->mem_res;
> +     struct resource *bus_range = rc->bus_range;
> +     struct device *dev = rc->dev;
> +     struct device_node *np = dev->of_node;
> +     struct of_pci_range_parser parser;
> +     struct of_pci_range range;
> +     u32 addr0, addr1, desc1;
> +     u64 cpu_addr;
> +     int r, err;
> +
> +     /*
> +      * Reserve region 0 for PCI configure space accesses:
> +      * OB_REGION_PCI_ADDR0 and OB_REGION_DESC0 are updated dynamically by
> +      * cdns_pci_map_bus(), other region registers are set here once for all.
> +      */
> +     addr1 = 0; /* Should be programmed to zero. */
> +     desc1 = CDNS_PCIE_AT_OB_REGION_DESC1_BUS(bus_range->start);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(0), addr1);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(0), desc1);
> +
> +     cpu_addr = cfg_res->start - mem_res->start;
> +     addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(12) |
> +             (lower_32_bits(cpu_addr) & GENMASK(31, 8));
> +     addr1 = upper_32_bits(cpu_addr);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(0), addr0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(0), addr1);
> +
> +     err = of_pci_range_parser_init(&parser, np);
> +     if (err)
> +             return err;
> +
> +     r = 1;
> +     for_each_of_pci_range(&parser, &range) {
> +             bool is_io;
> +
> +             if (r >= rc->data->max_regions)
> +                     break;
> +
> +             if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
> +                     is_io = false;
> +             else if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO)
> +                     is_io = true;
> +             else
> +                     continue;
> +
> +             cdns_pcie_set_outbound_region(pcie, r, is_io,
> +                                           range.cpu_addr,
> +                                           range.pci_addr,
> +                                           range.size);
> +             r++;
> +     }
> +
> +     /*
> +      * Set Root Port no BAR match Inbound Translation registers:
> +      * needed for MSI.

And DMA :) if I understand what this is doing correctly, ie setting
the root complex decoding for incoming memory traffic.

> +      * Root Port BAR0 and BAR1 are disabled, hence no need to set their
> +      * inbound translation registers.
> +      */
> +     addr0 = CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS(rc->data->no_bar_nbits);
> +     addr1 = 0;
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR0(RP_NO_BAR), addr0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR1(RP_NO_BAR), addr1);
> +
> +     return 0;
> +}
> +
> +static int cdns_pcie_host_init(struct device *dev,
> +                            struct list_head *resources,
> +                            struct cdns_pcie_rc *rc)
> +{
> +     struct resource *bus_range = NULL;
> +     int err;
> +
> +     /* Parse our PCI ranges and request their resources */
> +     err = cdns_pcie_parse_request_of_pci_ranges(dev, resources, &bus_range);
> +     if (err)
> +             goto err_out;

I think that the err_out path should be part of:

cdns_pcie_parse_request_of_pci_ranges()

implementation and here you would just return.

> +
> +     if (bus_range->start > bus_range->end) {
> +             err = -EINVAL;
> +             goto err_out;
> +     }

Add a space here; this check seems useless to me anyway.

> +     rc->bus_range = bus_range;
> +     rc->pcie.bus = bus_range->start;
> +
> +     err = cdns_pcie_host_init_root_port(rc);
> +     if (err)
> +             goto err_out;
> +
> +     err = cdns_pcie_host_init_address_translation(rc);
> +     if (err)
> +             goto err_out;
> +
> +     return 0;
> +
> + err_out:
> +     pci_free_resource_list(resources);

See above.

> +     return err;
> +}
> +
> +static int cdns_pcie_host_probe(struct platform_device *pdev)
> +{
> +     const struct of_device_id *of_id;
> +     const char *type;
> +     struct device *dev = &pdev->dev;
> +     struct device_node *np = dev->of_node;
> +     struct pci_bus *bus, *child;
> +     struct pci_host_bridge *bridge;
> +     struct list_head resources;
> +     struct cdns_pcie_rc *rc;
> +     struct cdns_pcie *pcie;
> +     struct resource *res;
> +     int ret;
> +
> +     bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
> +     if (!bridge)
> +             return -ENOMEM;
> +
> +     rc = pci_host_bridge_priv(bridge);
> +     rc->dev = dev;
> +     platform_set_drvdata(pdev, rc);

I do not think it is needed.

> +     pcie = &rc->pcie;
> +     pcie->is_rc = true;
> +
> +     of_id = of_match_node(cdns_pcie_host_of_match, np);
> +     rc->data = (const struct cdns_pcie_rc_data *)of_id->data;
> +
> +     type = of_get_property(np, "device_type", NULL);
> +     if (!type || strcmp(type, "pci")) {
> +             dev_err(dev, "invalid \"device_type\" %s\n", type);
> +             return -EINVAL;
> +     }
> +
> +     res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "reg");
> +     pcie->reg_base = devm_ioremap_resource(dev, res);
> +     if (IS_ERR(pcie->reg_base)) {
> +             dev_err(dev, "missing \"reg\"\n");
> +             return PTR_ERR(pcie->reg_base);
> +     }
> +
> +     res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
> +     rc->cfg_base = devm_ioremap_resource(dev, res);

devm_pci_remap_cfg_resource() please.

> +     if (IS_ERR(rc->cfg_base)) {
> +             dev_err(dev, "missing \"cfg\"\n");
> +             return PTR_ERR(rc->cfg_base);
> +     }
> +     rc->cfg_res = res;
> +
> +     res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem");
> +     if (!res) {
> +             dev_err(dev, "missing \"mem\"\n");
> +             return -EINVAL;
> +     }
> +     pcie->mem_res = res;
> +
> +     pm_runtime_enable(dev);
> +     ret = pm_runtime_get_sync(dev);
> +     if (ret < 0) {
> +             dev_err(dev, "pm_runtime_get_sync() failed\n");
> +             goto err_get_sync;
> +     }
> +
> +     INIT_LIST_HEAD(&resources);
> +     ret = cdns_pcie_host_init(dev, &resources, rc);
> +     if (ret)
> +             goto err_init;
> +
> +     list_splice_init(&resources, &bridge->windows);
> +     bridge->dev.parent = dev;
> +     bridge->busnr = pcie->bus;
> +     bridge->ops = &cdns_pcie_host_ops;
> +     bridge->map_irq = of_irq_parse_and_map_pci;
> +     bridge->swizzle_irq = pci_common_swizzle;
> +
> +     ret = pci_scan_root_bus_bridge(bridge);
> +     if (ret < 0) {
> +             dev_err(dev, "Scanning root bridge failed");
> +             goto err_init;
> +     }
> +
> +     bus = bridge->bus;
> +     pci_bus_size_bridges(bus);
> +     pci_bus_assign_resources(bus);
> +
> +     list_for_each_entry(child, &bus->children, node)
> +             pcie_bus_configure_settings(child);
> +
> +     pci_bus_add_devices(bus);
> +
> +     return 0;
> +
> + err_init:
> +     pm_runtime_put_sync(dev);
> +
> + err_get_sync:
> +     pm_runtime_disable(dev);
> +
> +     return ret;
> +}
> +
> +static struct platform_driver cdns_pcie_host_driver = {
> +     .driver = {
> +             .name = "cdns-pcie-host",
> +             .of_match_table = cdns_pcie_host_of_match,
> +     },
> +     .probe = cdns_pcie_host_probe,
> +};
> +builtin_platform_driver(cdns_pcie_host_driver);
> diff --git a/drivers/pci/cadence/pcie-cadence.c b/drivers/pci/cadence/pcie-cadence.c
> new file mode 100644
> index 000000000000..5c10879d5e96
> --- /dev/null
> +++ b/drivers/pci/cadence/pcie-cadence.c
> @@ -0,0 +1,110 @@
> +/*
> + * Cadence PCIe controller driver.
> + *
> + * Copyright (c) 2017 Cadence
> + *
> + * Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/kernel.h>
> +
> +#include "pcie-cadence.h"
> +
> +void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u32 r, bool is_io,
> +                                u64 cpu_addr, u64 pci_addr, size_t size)
> +{
> +     /*
> +      * roundup_pow_of_two() returns an unsigned long, which is not suited
> +      * for 64bit values.
> +      */
> +     u64 sz = 1ULL << fls64(size - 1);
> +     int nbits = ilog2(sz);
> +     u32 addr0, addr1, desc0, desc1;
> +
> +     if (nbits < 8)
> +             nbits = 8;
> +
> +     /* Set the PCI address */
> +     addr0 = CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(nbits) |
> +             (lower_32_bits(pci_addr) & GENMASK(31, 8));
> +     addr1 = upper_32_bits(pci_addr);
> +
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), addr0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), addr1);
> +
> +     /* Set the PCIe header descriptor */
> +     if (is_io)
> +             desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_IO;
> +     else
> +             desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_MEM;
> +     desc1 = 0;
> +
> +     if (pcie->is_rc) {
> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
> +                      CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
> +             desc1 |= CDNS_PCIE_AT_OB_REGION_DESC1_BUS(pcie->bus);
> +     }
> +
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), desc0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), desc1);
> +
> +     /* Set the CPU address */
> +     cpu_addr -= pcie->mem_res->start;
> +     addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(nbits) |
> +             (lower_32_bits(cpu_addr) & GENMASK(31, 8));
> +     addr1 = upper_32_bits(cpu_addr);
> +
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), addr0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), addr1);
> +}
> +
> +void cdns_pcie_set_outbound_region_for_normal_msg(struct cdns_pcie *pcie, u32 r,
> +                                               u64 cpu_addr)

Not used in this patch, you should split it out.

> +{
> +     u32 addr0, addr1, desc0, desc1;
> +
> +     desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_NORMAL_MSG;
> +     desc1 = 0;
> +     if (pcie->is_rc) {
> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
> +                      CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
> +             desc1 |= CDNS_PCIE_AT_OB_REGION_DESC1_BUS(pcie->bus);
> +     }
> +
> +     /* Set the CPU address */
> +     cpu_addr -= pcie->mem_res->start;
> +     addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(17) |
> +             (lower_32_bits(cpu_addr) & GENMASK(31, 8));
> +     addr1 = upper_32_bits(cpu_addr);
> +
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), 0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), 0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), desc0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), desc1);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), addr0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), addr1);
> +}
> +
> +void cdns_pcie_reset_outbound_region(struct cdns_pcie *pcie, u32 r)
> +{
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), 0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), 0);
> +
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), 0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), 0);
> +
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), 0);
> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), 0);
> +}
> diff --git a/drivers/pci/cadence/pcie-cadence.h b/drivers/pci/cadence/pcie-cadence.h
> new file mode 100644
> index 000000000000..195e23b7d4fe
> --- /dev/null
> +++ b/drivers/pci/cadence/pcie-cadence.h
> @@ -0,0 +1,325 @@
> +/*
> + * Cadence PCIe controller driver.
> + *
> + * Copyright (c) 2017 Cadence
> + *
> + * Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef _PCIE_CADENCE_H
> +#define _PCIE_CADENCE_H
> +
> +#include <linux/kernel.h>
> +#include <linux/pci.h>
> +
> +/*
> + * Local Management Registers
> + */
> +#define CDNS_PCIE_LM_BASE    0x00100000
> +
> +/* Vendor ID Register */
> +#define CDNS_PCIE_LM_ID              (CDNS_PCIE_LM_BASE + 0x0044)
> +#define  CDNS_PCIE_LM_ID_VENDOR_MASK GENMASK(15, 0)
> +#define  CDNS_PCIE_LM_ID_VENDOR_SHIFT        0
> +#define  CDNS_PCIE_LM_ID_VENDOR(vid) \
> +     (((vid) << CDNS_PCIE_LM_ID_VENDOR_SHIFT) & CDNS_PCIE_LM_ID_VENDOR_MASK)
> +#define  CDNS_PCIE_LM_ID_SUBSYS_MASK GENMASK(31, 16)
> +#define  CDNS_PCIE_LM_ID_SUBSYS_SHIFT        16
> +#define  CDNS_PCIE_LM_ID_SUBSYS(sub) \
> +     (((sub) << CDNS_PCIE_LM_ID_SUBSYS_SHIFT) & CDNS_PCIE_LM_ID_SUBSYS_MASK)
> +
> +/* Root Port Requestor ID Register */
> +#define CDNS_PCIE_LM_RP_RID  (CDNS_PCIE_LM_BASE + 0x0228)
> +#define  CDNS_PCIE_LM_RP_RID_MASK    GENMASK(15, 0)
> +#define  CDNS_PCIE_LM_RP_RID_SHIFT   0
> +#define  CDNS_PCIE_LM_RP_RID_(rid) \
> +     (((rid) << CDNS_PCIE_LM_RP_RID_SHIFT) & CDNS_PCIE_LM_RP_RID_MASK)
> +
> +/* Endpoint Bus and Device Number Register */
> +#define CDNS_PCIE_LM_EP_ID   (CDNS_PCIE_LM_BASE + 0x022c)
> +#define  CDNS_PCIE_LM_EP_ID_DEV_MASK GENMASK(4, 0)
> +#define  CDNS_PCIE_LM_EP_ID_DEV_SHIFT        0
> +#define  CDNS_PCIE_LM_EP_ID_BUS_MASK GENMASK(15, 8)
> +#define  CDNS_PCIE_LM_EP_ID_BUS_SHIFT        8
> +
> +/* Endpoint Function f BAR b Configuration Registers */
> +#define CDNS_PCIE_LM_EP_FUNC_BAR_CFG0(fn) \
> +     (CDNS_PCIE_LM_BASE + 0x0240 + (fn) * 0x0008)
> +#define CDNS_PCIE_LM_EP_FUNC_BAR_CFG1(fn) \
> +     (CDNS_PCIE_LM_BASE + 0x0244 + (fn) * 0x0008)
> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b) \
> +     (GENMASK(4, 0) << ((b) * 8))
> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE(b, a) \
> +     (((a) << ((b) * 8)) & CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b))
> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b) \
> +     (GENMASK(7, 5) << ((b) * 8))
> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL(b, c) \
> +     (((c) << ((b) * 8 + 5)) & CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b))
> +
> +/* Endpoint Function Configuration Register */
> +#define CDNS_PCIE_LM_EP_FUNC_CFG     (CDNS_PCIE_LM_BASE + 0x02c0)

All endpoint defines should be moved to the patch that needs them.

> +
> +/* Root Complex BAR Configuration Register */
> +#define CDNS_PCIE_LM_RC_BAR_CFG      (CDNS_PCIE_LM_BASE + 0x0300)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_APERTURE_MASK  GENMASK(5, 0)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_APERTURE(a) \
> +     (((a) << 0) & CDNS_PCIE_LM_RC_BAR_CFG_BAR0_APERTURE_MASK)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL_MASK              GENMASK(8, 6)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(c) \
> +     (((c) << 6) & CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL_MASK)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_APERTURE_MASK  GENMASK(13, 9)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_APERTURE(a) \
> +     (((a) << 9) & CDNS_PCIE_LM_RC_BAR_CFG_BAR1_APERTURE_MASK)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL_MASK              GENMASK(16, 14)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(c) \
> +     (((c) << 14) & CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL_MASK)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE BIT(17)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_32BITS 0
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS BIT(18)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE           BIT(19)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_IO_16BITS           0
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS           BIT(20)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_CHECK_ENABLE                BIT(31)
> +
> +/* BAR control values applicable to both Endpoint Function and Root Complex */
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED          0x0
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_IO_32BITS         0x1
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_MEM_32BITS                0x4
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_PREFETCH_MEM_32BITS       0x5
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_MEM_64BITS                0x6
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_PREFETCH_MEM_64BITS       0x7
> +
> +
> +/*
> + * Endpoint Function Registers (PCI configuration space for endpoint functions)
> + */
> +#define CDNS_PCIE_EP_FUNC_BASE(fn)   (((fn) << 12) & GENMASK(19, 12))
> +
> +#define CDNS_PCIE_EP_FUNC_MSI_CAP_OFFSET     0x90
> +
> +/*
> + * Root Port Registers (PCI configuration space for the root port function)
> + */
> +#define CDNS_PCIE_RP_BASE    0x00200000
> +
> +
> +/*
> + * Address Translation Registers
> + */
> +#define CDNS_PCIE_AT_BASE    0x00400000
> +
> +/* Region r Outbound AXI to PCIe Address Translation Register 0 */
> +#define CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r) \
> +     (CDNS_PCIE_AT_BASE + 0x0000 + ((r) & 0x1f) * 0x0020)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS_MASK GENMASK(5, 0)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(nbits) \
> +     (((nbits) - 1) & CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS_MASK)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN_MASK GENMASK(19, 12)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN(devfn) \
> +     (((devfn) << 12) & CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN_MASK)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS_MASK   GENMASK(27, 20)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS(bus) \
> +     (((bus) << 20) & CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS_MASK)
> +
> +/* Region r Outbound AXI to PCIe Address Translation Register 1 */
> +#define CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r) \
> +     (CDNS_PCIE_AT_BASE + 0x0004 + ((r) & 0x1f) * 0x0020)
> +
> +/* Region r Outbound PCIe Descriptor Register 0 */
> +#define CDNS_PCIE_AT_OB_REGION_DESC0(r) \
> +     (CDNS_PCIE_AT_BASE + 0x0008 + ((r) & 0x1f) * 0x0020)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_MASK              GENMASK(3, 0)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_MEM               0x2
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_IO                0x6
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE0        0xa
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE1        0xb
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_NORMAL_MSG        0xc
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_VENDOR_MSG        0xd
> +/* Bit 23 MUST be set in RC mode. */
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID  BIT(23)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN_MASK     GENMASK(31, 24)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(devfn) \
> +     (((devfn) << 24) & CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN_MASK)
> +
> +/* Region r Outbound PCIe Descriptor Register 1 */
> +#define CDNS_PCIE_AT_OB_REGION_DESC1(r)      \
> +     (CDNS_PCIE_AT_BASE + 0x000c + ((r) & 0x1f) * 0x0020)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC1_BUS_MASK       GENMASK(7, 0)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC1_BUS(bus) \
> +     ((bus) & CDNS_PCIE_AT_OB_REGION_DESC1_BUS_MASK)
> +
> +/* Region r AXI Region Base Address Register 0 */
> +#define CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r) \
> +     (CDNS_PCIE_AT_BASE + 0x0018 + ((r) & 0x1f) * 0x0020)
> +#define  CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS_MASK GENMASK(5, 0)
> +#define  CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(nbits) \
> +     (((nbits) - 1) & CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS_MASK)
> +
> +/* Region r AXI Region Base Address Register 1 */
> +#define CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r) \
> +     (CDNS_PCIE_AT_BASE + 0x001c + ((r) & 0x1f) * 0x0020)
> +
> +/* Root Port BAR Inbound PCIe to AXI Address Translation Register */
> +#define CDNS_PCIE_AT_IB_RP_BAR_ADDR0(bar) \
> +     (CDNS_PCIE_AT_BASE + 0x0800 + (bar) * 0x0008)
> +#define  CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS_MASK     GENMASK(5, 0)
> +#define  CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS(nbits) \
> +     (((nbits) - 1) & CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS_MASK)
> +#define CDNS_PCIE_AT_IB_RP_BAR_ADDR1(bar) \
> +     (CDNS_PCIE_AT_BASE + 0x0804 + (bar) * 0x0008)
> +
> +enum cdns_pcie_rp_bar {
> +     RP_BAR0,
> +     RP_BAR1,
> +     RP_NO_BAR
> +};
> +
> +/* Endpoint Function BAR Inbound PCIe to AXI Address Translation Register */
> +#define CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR0(fn, bar) \
> +     (CDNS_PCIE_AT_BASE + 0x0840 + (fn) * 0x0040 + (bar) * 0x0008)
> +#define CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR1(fn, bar) \
> +     (CDNS_PCIE_AT_BASE + 0x0844 + (fn) * 0x0040 + (bar) * 0x0008)
> +
> +/* Normal/Vendor specific message access: offset inside some outbound region */
> +#define CDNS_PCIE_NORMAL_MSG_ROUTING_MASK    GENMASK(7, 5)
> +#define CDNS_PCIE_NORMAL_MSG_ROUTING(route) \
> +     (((route) << 5) & CDNS_PCIE_NORMAL_MSG_ROUTING_MASK)
> +#define CDNS_PCIE_NORMAL_MSG_CODE_MASK               GENMASK(15, 8)
> +#define CDNS_PCIE_NORMAL_MSG_CODE(code) \
> +     (((code) << 8) & CDNS_PCIE_NORMAL_MSG_CODE_MASK)
> +#define CDNS_PCIE_MSG_NO_DATA                        BIT(16)
> +
> +enum cdns_pcie_msg_code {
> +     MSG_CODE_ASSERT_INTA    = 0x20,
> +     MSG_CODE_ASSERT_INTB    = 0x21,
> +     MSG_CODE_ASSERT_INTC    = 0x22,
> +     MSG_CODE_ASSERT_INTD    = 0x23,
> +     MSG_CODE_DEASSERT_INTA  = 0x24,
> +     MSG_CODE_DEASSERT_INTB  = 0x25,
> +     MSG_CODE_DEASSERT_INTC  = 0x26,
> +     MSG_CODE_DEASSERT_INTD  = 0x27,
> +};
> +
> +enum cdns_pcie_msg_routing {
> +     /* Route to Root Complex */
> +     MSG_ROUTING_TO_RC,
> +
> +     /* Use Address Routing */
> +     MSG_ROUTING_BY_ADDR,
> +
> +     /* Use ID Routing */
> +     MSG_ROUTING_BY_ID,
> +
> +     /* Route as Broadcast Message from Root Complex */
> +     MSG_ROUTING_BCAST,
> +
> +     /* Local message; terminate at receiver (INTx messages) */
> +     MSG_ROUTING_LOCAL,
> +
> +     /* Gather & route to Root Complex (PME_TO_Ack message) */
> +     MSG_ROUTING_GATHER,
> +};
> +
> +/**
> + * struct cdns_pcie - private data for Cadence PCIe controller drivers
> + * @reg_base: IO mapped register base
> + * @mem_res: start/end offsets in the physical system memory to map PCI accesses
> + * @is_rc: tell whether the PCIe controller mode is Root Complex or Endpoint.
> + * @bus: In Root Complex mode, the bus number
> + */
> +struct cdns_pcie {
> +     void __iomem            *reg_base;
> +     struct resource         *mem_res;
> +     bool                    is_rc;
> +     u8                      bus;
> +};
> +
> +/* Register access */
> +static inline void cdns_pcie_writeb(struct cdns_pcie *pcie, u32 reg, u8 value)
> +{
> +     writeb(value, pcie->reg_base + reg);
> +}
> +
> +static inline void cdns_pcie_writew(struct cdns_pcie *pcie, u32 reg, u16 value)
> +{
> +     writew(value, pcie->reg_base + reg);
> +}
> +
> +static inline void cdns_pcie_writel(struct cdns_pcie *pcie, u32 reg, u32 value)
> +{
> +     writel(value, pcie->reg_base + reg);
> +}
> +
> +static inline u32 cdns_pcie_readl(struct cdns_pcie *pcie, u32 reg)
> +{
> +     return readl(pcie->reg_base + reg);
> +}
> +
> +/* Root Port register access */
> +static inline void cdns_pcie_rp_writeb(struct cdns_pcie *pcie,
> +                                    u32 reg, u8 value)
> +{
> +     writeb(value, pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
> +}
> +
> +static inline void cdns_pcie_rp_writew(struct cdns_pcie *pcie,
> +                                    u32 reg, u16 value)
> +{
> +     writew(value, pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
> +}
> +
> +/* Endpoint Function register access */
> +static inline void cdns_pcie_ep_fn_writeb(struct cdns_pcie *pcie, u8 fn,
> +                                       u32 reg, u8 value)
> +{
> +     writeb(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}
> +
> +static inline void cdns_pcie_ep_fn_writew(struct cdns_pcie *pcie, u8 fn,
> +                                       u32 reg, u16 value)
> +{
> +     writew(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}
> +
> +static inline void cdns_pcie_ep_fn_writel(struct cdns_pcie *pcie, u8 fn,
> +                                       u32 reg, u16 value)
> +{
> +     writel(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}
> +
> +static inline u8 cdns_pcie_ep_fn_readb(struct cdns_pcie *pcie, u8 fn, u32 reg)
> +{
> +     return readb(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}
> +
> +static inline u16 cdns_pcie_ep_fn_readw(struct cdns_pcie *pcie, u8 fn, u32 reg)
> +{
> +     return readw(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}
> +
> +static inline u32 cdns_pcie_ep_fn_readl(struct cdns_pcie *pcie, u8 fn, u32 reg)
> +{
> +     return readl(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}

Same comments for all endpoint related functions and defines above.

Thanks,
Lorenzo

> +void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u32 r, bool is_io,
> +                                u64 cpu_addr, u64 pci_addr, size_t size);
> +
> +void cdns_pcie_set_outbound_region_for_normal_msg(struct cdns_pcie *pcie, u32 r,
> +                                               u64 cpu_addr);
> +
> +void cdns_pcie_reset_outbound_region(struct cdns_pcie *pcie, u32 r);
> +
> +#endif /* _PCIE_CADENCE_H */
> --
> 2.11.0
>
IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

[w/o unintended disclaimer]

On Thu, Nov 23, 2017 at 04:01:48PM +0100, Cyrille Pitchen wrote:
> This patch adds support to the Cadence PCIe controller in host mode.

Bjorn already commented on this, it would be good to add some
of the cover letter details in this log.

> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> ---
>  drivers/Makefile                        |   1 +
>  drivers/pci/Kconfig                     |   1 +
>  drivers/pci/cadence/Kconfig             |  24 ++
>  drivers/pci/cadence/Makefile            |   2 +
>  drivers/pci/cadence/pcie-cadence-host.c | 425 ++++++++++++++++++++++++++++++++

You should also update the MAINTAINERS file.

>  drivers/pci/cadence/pcie-cadence.c      | 110 +++++++++
>  drivers/pci/cadence/pcie-cadence.h      | 325 ++++++++++++++++++++++++
>  7 files changed, 888 insertions(+)
>  create mode 100644 drivers/pci/cadence/Kconfig
>  create mode 100644 drivers/pci/cadence/Makefile
>  create mode 100644 drivers/pci/cadence/pcie-cadence-host.c
>  create mode 100644 drivers/pci/cadence/pcie-cadence.c
>  create mode 100644 drivers/pci/cadence/pcie-cadence.h
> 
> diff --git a/drivers/Makefile b/drivers/Makefile
> index 1d034b680431..27bdd98784d9 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -18,6 +18,7 @@ obj-y				+= pwm/
>  
>  obj-$(CONFIG_PCI)		+= pci/
>  obj-$(CONFIG_PCI_ENDPOINT)	+= pci/endpoint/
> +obj-$(CONFIG_PCI_CADENCE)	+= pci/cadence/

Already commented on the cover letter.

>  # PCI dwc controller drivers
>  obj-y				+= pci/dwc/
>  
> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> index 90944667ccea..2471b2e36b8b 100644
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -144,6 +144,7 @@ config PCI_HYPERV
>            PCI devices from a PCI backend to support PCI driver domains.
>  
>  source "drivers/pci/hotplug/Kconfig"
> +source "drivers/pci/cadence/Kconfig"
>  source "drivers/pci/dwc/Kconfig"
>  source "drivers/pci/host/Kconfig"
>  source "drivers/pci/endpoint/Kconfig"
> diff --git a/drivers/pci/cadence/Kconfig b/drivers/pci/cadence/Kconfig
> new file mode 100644
> index 000000000000..120306cae2aa
> --- /dev/null
> +++ b/drivers/pci/cadence/Kconfig
> @@ -0,0 +1,24 @@
> +menuconfig PCI_CADENCE
> +	bool "Cadence PCI controllers support"
> +	depends on PCI && HAS_IOMEM
> +	help
> +	  Say Y here if you want to support some Cadence PCI controller.
> +
> +	  When in doubt, say N.
> +
> +if PCI_CADENCE
> +
> +config PCIE_CADENCE
> +	bool
> +
> +config PCIE_CADENCE_HOST
> +	bool "Cadence PCIe host controller"
> +	depends on OF
> +	depends on PCI_MSI_IRQ_DOMAIN

I do not see the reason for this dependency in the code.

> +	select PCIE_CADENCE
> +	help
> +	  Say Y here if you want to support the Cadence PCIe controller in host
> +	  mode. This PCIe controller may be embedded into many different vendors
> +	  SoCs.
> +
> +endif # PCI_CADENCE
> diff --git a/drivers/pci/cadence/Makefile b/drivers/pci/cadence/Makefile
> new file mode 100644
> index 000000000000..d57d192d2595
> --- /dev/null
> +++ b/drivers/pci/cadence/Makefile
> @@ -0,0 +1,2 @@
> +obj-$(CONFIG_PCIE_CADENCE) += pcie-cadence.o
> +obj-$(CONFIG_PCIE_CADENCE_HOST) += pcie-cadence-host.o
> diff --git a/drivers/pci/cadence/pcie-cadence-host.c b/drivers/pci/cadence/pcie-cadence-host.c
> new file mode 100644
> index 000000000000..252471e72a93
> --- /dev/null
> +++ b/drivers/pci/cadence/pcie-cadence-host.c
> @@ -0,0 +1,425 @@
> +/*
> + * Cadence PCIe host controller driver.
> + *
> + * Copyright (c) 2017 Cadence
> + *
> + * Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +#include <linux/kernel.h>
> +#include <linux/of_address.h>
> +#include <linux/of_pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +
> +#include "pcie-cadence.h"
> +
> +/**
> + * struct cdns_pcie_rc_data - hardware specific data
> + * @max_regions: maximum number of regions supported by the hardware
> + * @vendor_id: PCI vendor ID
> + * @device_id: PCI device ID
> + * @no_bar_nbits: Number of bits to keep for inbound (PCIe -> CPU) address
> + *                translation (nbits sets into the "no BAR match" register).
> + */
> +struct cdns_pcie_rc_data {
> +	size_t			max_regions;

Reason for it to be size_t ?

> +	u16			vendor_id;
> +	u16			device_id;
> +	u8			no_bar_nbits;
> +};

I think that this data should come from DT (?) more below.

> +
> +/**
> + * struct cdns_pcie_rc - private data for this PCIe Root Complex driver
> + * @pcie: Cadence PCIe controller
> + * @dev: pointer to PCIe device
> + * @cfg_res: start/end offsets in the physical system memory to map PCI
> + *           configuration space accesses
> + * @bus_range: first/last buses behind the PCIe host controller
> + * @cfg_base: IO mapped window to access the PCI configuration space of a
> + *            single function at a time
> + * @data: pointer to a 'struct cdns_pcie_rc_data'
> + */
> +struct cdns_pcie_rc {
> +	struct cdns_pcie	pcie;
> +	struct device		*dev;
> +	struct resource		*cfg_res;
> +	struct resource		*bus_range;
> +	void __iomem		*cfg_base;
> +	const struct cdns_pcie_rc_data	*data;
> +};
> +
> +static void __iomem *

Please do not split lines like this, storage class and return type
should be in the same line as the name, move parameter(s) to a new
line.

static void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
				      int where)

> +cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn, int where)
> +{
> +	struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
> +	struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
> +	struct cdns_pcie *pcie = &rc->pcie;
> +	unsigned int busn = bus->number;
> +	u32 addr0, desc0;
> +
> +	if (busn < rc->bus_range->start || busn > rc->bus_range->end)
> +		return NULL;

It does not hurt but I wonder whether you really need this check.

> +	if (busn == rc->bus_range->start) {
> +		if (devfn)

I suspect I know why you need this check but I ask you to explain it
anyway if you do not mind please.

> +			return NULL;
> +
> +		return pcie->reg_base + (where & 0xfff);
> +	}
> +
> +	/* Update Output registers for AXI region 0. */
> +	addr0 = CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(12) |

Ok, so for every config access you reprogram addr0 to reflect the
correct bus|devfn ID in the PCI bus TLP corresponding to an ECAM address
in CPU physical address space, is my understanding correct ?

> +		CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN(devfn) |
> +		CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS(busn);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(0), addr0);
> +
> +	/* Configuration Type 0 or Type 1 access. */
> +	desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
> +		CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
> +	/*
> +	 * The bus number was already set once for all in desc1 by
> +	 * cdns_pcie_host_init_address_translation().
> +	 */
> +	if (busn == rc->bus_range->start + 1)
> +		desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE0;
> +	else
> +		desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE1;

I would like to ask you why you have to do it here and the root port
does not figure it out by itself, I do not have the datasheet so I am
just asking for my own information.

> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(0), desc0);
> +
> +	return rc->cfg_base + (where & 0xfff);
> +}
> +
> +static struct pci_ops cdns_pcie_host_ops = {
> +	.map_bus	= cdns_pci_map_bus,
> +	.read		= pci_generic_config_read,
> +	.write		= pci_generic_config_write,
> +};
> +
> +static const struct cdns_pcie_rc_data cdns_pcie_rc_data = {
> +	.max_regions	= 32,
> +	.vendor_id	= PCI_VENDOR_ID_CDNS,
> +	.device_id	= 0x0200,
> +	.no_bar_nbits	= 32,
> +};

Should (some of) these parameters be retrieved through a DT binding ?

> +static const struct of_device_id cdns_pcie_host_of_match[] = {
> +	{ .compatible = "cdns,cdns-pcie-host",
> +	  .data = &cdns_pcie_rc_data },
> +
> +	{ },
> +};
> +
> +static int cdns_pcie_parse_request_of_pci_ranges(struct device *dev,
> +						 struct list_head *resources,
> +						 struct resource **bus_range)
> +{
> +	int err, res_valid = 0;
> +	struct device_node *np = dev->of_node;
> +	resource_size_t iobase;
> +	struct resource_entry *win, *tmp;
> +
> +	err = of_pci_get_host_bridge_resources(np, 0, 0xff, resources, &iobase);
> +	if (err)
> +		return err;
> +
> +	err = devm_request_pci_bus_resources(dev, resources);
> +	if (err)
> +		return err;
> +
> +	resource_list_for_each_entry_safe(win, tmp, resources) {
> +		struct resource *res = win->res;
> +
> +		switch (resource_type(res)) {
> +		case IORESOURCE_IO:
> +			err = pci_remap_iospace(res, iobase);
> +			if (err) {
> +				dev_warn(dev, "error %d: failed to map resource %pR\n",
> +					 err, res);
> +				resource_list_destroy_entry(win);
> +			}
> +			break;
> +		case IORESOURCE_MEM:
> +			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
> +			break;
> +		case IORESOURCE_BUS:
> +			*bus_range = res;
> +			break;
> +		}
> +	}
> +
> +	if (res_valid)
> +		return 0;
> +
> +	dev_err(dev, "non-prefetchable memory resource required\n");
> +	return -EINVAL;

Nit, I prefer you swap these two as it is done in pci-aardvark.c:

	if (!res_valid) {
		dev_err(dev, "non-prefetchable memory resource required\n");
		return -EINVAL;
	}

	return 0;

but as per previous replies this function can be factorized in
core PCI code - I would not bother unless you are willing to write
the patch series that does the refactoring yourself :)

> +}
> +
> +static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
> +{
> +	const struct cdns_pcie_rc_data *data = rc->data;
> +	struct cdns_pcie *pcie = &rc->pcie;
> +	u8 pbn, sbn, subn;
> +	u32 value, ctrl;
> +
> +	/*
> +	 * Set the root complex BAR configuration register:
> +	 * - disable both BAR0 and BAR1.
> +	 * - enable Prefetchable Memory Base and Limit registers in type 1
> +	 *   config space (64 bits).
> +	 * - enable IO Base and Limit registers in type 1 config
> +	 *   space (32 bits).
> +	 */
> +	ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
> +	value = CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(ctrl) |
> +		CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(ctrl) |
> +		CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE |
> +		CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS |
> +		CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE |
> +		CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS;
> +	cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
> +
> +	/* Set root port configuration space */
> +	if (data->vendor_id != 0xffff)
> +		cdns_pcie_rp_writew(pcie, PCI_VENDOR_ID, data->vendor_id);
> +	if (data->device_id != 0xffff)
> +		cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, data->device_id);
> +
> +	cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
> +	cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
> +	cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
> +
> +	pbn = rc->bus_range->start;
> +	sbn = pbn + 1; /* Single root port. */
> +	subn = rc->bus_range->end;
> +	cdns_pcie_rp_writeb(pcie, PCI_PRIMARY_BUS, pbn);
> +	cdns_pcie_rp_writeb(pcie, PCI_SECONDARY_BUS, sbn);
> +	cdns_pcie_rp_writeb(pcie, PCI_SUBORDINATE_BUS, subn);

Again - I do not have the datasheet for this device therefore I would
kindly ask you how this works; it seems to me that what you are doing
here is done through normal configuration cycles in an ECAM compliant
system to program the RP PRIMARY/SECONDARY/SUBORDINATE bus - I would
like to understand why this code is needed.

> +	return 0;
> +}
> +
> +static int cdns_pcie_host_init_address_translation(struct cdns_pcie_rc *rc)
> +{
> +	struct cdns_pcie *pcie = &rc->pcie;
> +	struct resource *cfg_res = rc->cfg_res;
> +	struct resource *mem_res = pcie->mem_res;
> +	struct resource *bus_range = rc->bus_range;
> +	struct device *dev = rc->dev;
> +	struct device_node *np = dev->of_node;
> +	struct of_pci_range_parser parser;
> +	struct of_pci_range range;
> +	u32 addr0, addr1, desc1;
> +	u64 cpu_addr;
> +	int r, err;
> +
> +	/*
> +	 * Reserve region 0 for PCI configure space accesses:
> +	 * OB_REGION_PCI_ADDR0 and OB_REGION_DESC0 are updated dynamically by
> +	 * cdns_pci_map_bus(), other region registers are set here once for all.
> +	 */
> +	addr1 = 0; /* Should be programmed to zero. */
> +	desc1 = CDNS_PCIE_AT_OB_REGION_DESC1_BUS(bus_range->start);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(0), addr1);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(0), desc1);
> +
> +	cpu_addr = cfg_res->start - mem_res->start;
> +	addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(12) |
> +		(lower_32_bits(cpu_addr) & GENMASK(31, 8));
> +	addr1 = upper_32_bits(cpu_addr);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(0), addr0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(0), addr1);
> +
> +	err = of_pci_range_parser_init(&parser, np);
> +	if (err)
> +		return err;
> +
> +	r = 1;
> +	for_each_of_pci_range(&parser, &range) {
> +		bool is_io;
> +
> +		if (r >= rc->data->max_regions)
> +			break;
> +
> +		if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
> +			is_io = false;
> +		else if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO)
> +			is_io = true;
> +		else
> +			continue;
> +
> +		cdns_pcie_set_outbound_region(pcie, r, is_io,
> +					      range.cpu_addr,
> +					      range.pci_addr,
> +					      range.size);
> +		r++;
> +	}
> +
> +	/*
> +	 * Set Root Port no BAR match Inbound Translation registers:
> +	 * needed for MSI.

And DMA :) if I understand what this is doing correctly, ie setting
the root complex decoding for incoming memory traffic.

> +	 * Root Port BAR0 and BAR1 are disabled, hence no need to set their
> +	 * inbound translation registers.
> +	 */
> +	addr0 = CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS(rc->data->no_bar_nbits);
> +	addr1 = 0;
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR0(RP_NO_BAR), addr0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR1(RP_NO_BAR), addr1);
> +
> +	return 0;
> +}
> +
> +static int cdns_pcie_host_init(struct device *dev,
> +			       struct list_head *resources,
> +			       struct cdns_pcie_rc *rc)
> +{
> +	struct resource *bus_range = NULL;
> +	int err;
> +
> +	/* Parse our PCI ranges and request their resources */
> +	err = cdns_pcie_parse_request_of_pci_ranges(dev, resources, &bus_range);
> +	if (err)
> +		goto err_out;

I think that the err_out path should be part of:

cdns_pcie_parse_request_of_pci_ranges()

implementation and here you would just return.

> +
> +	if (bus_range->start > bus_range->end) {
> +		err = -EINVAL;
> +		goto err_out;
> +	}

Add a space here; this check seems useless to me anyway.

> +	rc->bus_range = bus_range;
> +	rc->pcie.bus = bus_range->start;
> +
> +	err = cdns_pcie_host_init_root_port(rc);
> +	if (err)
> +		goto err_out;
> +
> +	err = cdns_pcie_host_init_address_translation(rc);
> +	if (err)
> +		goto err_out;
> +
> +	return 0;
> +
> + err_out:
> +	pci_free_resource_list(resources);

See above.

> +	return err;
> +}
> +
> +static int cdns_pcie_host_probe(struct platform_device *pdev)
> +{
> +	const struct of_device_id *of_id;
> +	const char *type;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct pci_bus *bus, *child;
> +	struct pci_host_bridge *bridge;
> +	struct list_head resources;
> +	struct cdns_pcie_rc *rc;
> +	struct cdns_pcie *pcie;
> +	struct resource *res;
> +	int ret;
> +
> +	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
> +	if (!bridge)
> +		return -ENOMEM;
> +
> +	rc = pci_host_bridge_priv(bridge);
> +	rc->dev = dev;
> +	platform_set_drvdata(pdev, rc);

I do not think it is needed.

> +	pcie = &rc->pcie;
> +	pcie->is_rc = true;
> +
> +	of_id = of_match_node(cdns_pcie_host_of_match, np);
> +	rc->data = (const struct cdns_pcie_rc_data *)of_id->data;
> +
> +	type = of_get_property(np, "device_type", NULL);
> +	if (!type || strcmp(type, "pci")) {
> +		dev_err(dev, "invalid \"device_type\" %s\n", type);
> +		return -EINVAL;
> +	}
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "reg");
> +	pcie->reg_base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(pcie->reg_base)) {
> +		dev_err(dev, "missing \"reg\"\n");
> +		return PTR_ERR(pcie->reg_base);
> +	}
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
> +	rc->cfg_base = devm_ioremap_resource(dev, res);

devm_pci_remap_cfg_resource() please.

> +	if (IS_ERR(rc->cfg_base)) {
> +		dev_err(dev, "missing \"cfg\"\n");
> +		return PTR_ERR(rc->cfg_base);
> +	}
> +	rc->cfg_res = res;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem");
> +	if (!res) {
> +		dev_err(dev, "missing \"mem\"\n");
> +		return -EINVAL;
> +	}
> +	pcie->mem_res = res;
> +
> +	pm_runtime_enable(dev);
> +	ret = pm_runtime_get_sync(dev);
> +	if (ret < 0) {
> +		dev_err(dev, "pm_runtime_get_sync() failed\n");
> +		goto err_get_sync;
> +	}
> +
> +	INIT_LIST_HEAD(&resources);
> +	ret = cdns_pcie_host_init(dev, &resources, rc);
> +	if (ret)
> +		goto err_init;
> +
> +	list_splice_init(&resources, &bridge->windows);
> +	bridge->dev.parent = dev;
> +	bridge->busnr = pcie->bus;
> +	bridge->ops = &cdns_pcie_host_ops;
> +	bridge->map_irq = of_irq_parse_and_map_pci;
> +	bridge->swizzle_irq = pci_common_swizzle;
> +
> +	ret = pci_scan_root_bus_bridge(bridge);
> +	if (ret < 0) {
> +		dev_err(dev, "Scanning root bridge failed");
> +		goto err_init;
> +	}
> +
> +	bus = bridge->bus;
> +	pci_bus_size_bridges(bus);
> +	pci_bus_assign_resources(bus);
> +
> +	list_for_each_entry(child, &bus->children, node)
> +		pcie_bus_configure_settings(child);
> +
> +	pci_bus_add_devices(bus);
> +
> +	return 0;
> +
> + err_init:
> +	pm_runtime_put_sync(dev);
> +
> + err_get_sync:
> +	pm_runtime_disable(dev);
> +
> +	return ret;
> +}
> +
> +static struct platform_driver cdns_pcie_host_driver = {
> +	.driver = {
> +		.name = "cdns-pcie-host",
> +		.of_match_table = cdns_pcie_host_of_match,
> +	},
> +	.probe = cdns_pcie_host_probe,
> +};
> +builtin_platform_driver(cdns_pcie_host_driver);
> diff --git a/drivers/pci/cadence/pcie-cadence.c b/drivers/pci/cadence/pcie-cadence.c
> new file mode 100644
> index 000000000000..5c10879d5e96
> --- /dev/null
> +++ b/drivers/pci/cadence/pcie-cadence.c
> @@ -0,0 +1,110 @@
> +/*
> + * Cadence PCIe controller driver.
> + *
> + * Copyright (c) 2017 Cadence
> + *
> + * Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/kernel.h>
> +
> +#include "pcie-cadence.h"
> +
> +void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u32 r, bool is_io,
> +				   u64 cpu_addr, u64 pci_addr, size_t size)
> +{
> +	/*
> +	 * roundup_pow_of_two() returns an unsigned long, which is not suited
> +	 * for 64bit values.
> +	 */
> +	u64 sz = 1ULL << fls64(size - 1);
> +	int nbits = ilog2(sz);
> +	u32 addr0, addr1, desc0, desc1;
> +
> +	if (nbits < 8)
> +		nbits = 8;
> +
> +	/* Set the PCI address */
> +	addr0 = CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(nbits) |
> +		(lower_32_bits(pci_addr) & GENMASK(31, 8));
> +	addr1 = upper_32_bits(pci_addr);
> +
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), addr0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), addr1);
> +
> +	/* Set the PCIe header descriptor */
> +	if (is_io)
> +		desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_IO;
> +	else
> +		desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_MEM;
> +	desc1 = 0;
> +
> +	if (pcie->is_rc) {
> +		desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
> +			 CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
> +		desc1 |= CDNS_PCIE_AT_OB_REGION_DESC1_BUS(pcie->bus);
> +	}
> +
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), desc0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), desc1);
> +
> +	/* Set the CPU address */
> +	cpu_addr -= pcie->mem_res->start;
> +	addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(nbits) |
> +		(lower_32_bits(cpu_addr) & GENMASK(31, 8));
> +	addr1 = upper_32_bits(cpu_addr);
> +
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), addr0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), addr1);
> +}
> +
> +void cdns_pcie_set_outbound_region_for_normal_msg(struct cdns_pcie *pcie, u32 r,
> +						  u64 cpu_addr)

Not used in this patch, you should split it out.

> +{
> +	u32 addr0, addr1, desc0, desc1;
> +
> +	desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_NORMAL_MSG;
> +	desc1 = 0;
> +	if (pcie->is_rc) {
> +		desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
> +			 CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
> +		desc1 |= CDNS_PCIE_AT_OB_REGION_DESC1_BUS(pcie->bus);
> +	}
> +
> +	/* Set the CPU address */
> +	cpu_addr -= pcie->mem_res->start;
> +	addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(17) |
> +		(lower_32_bits(cpu_addr) & GENMASK(31, 8));
> +	addr1 = upper_32_bits(cpu_addr);
> +
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), 0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), 0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), desc0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), desc1);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), addr0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), addr1);
> +}
> +
> +void cdns_pcie_reset_outbound_region(struct cdns_pcie *pcie, u32 r)
> +{
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), 0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), 0);
> +
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), 0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), 0);
> +
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), 0);
> +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), 0);
> +}
> diff --git a/drivers/pci/cadence/pcie-cadence.h b/drivers/pci/cadence/pcie-cadence.h
> new file mode 100644
> index 000000000000..195e23b7d4fe
> --- /dev/null
> +++ b/drivers/pci/cadence/pcie-cadence.h
> @@ -0,0 +1,325 @@
> +/*
> + * Cadence PCIe controller driver.
> + *
> + * Copyright (c) 2017 Cadence
> + *
> + * Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef _PCIE_CADENCE_H
> +#define _PCIE_CADENCE_H
> +
> +#include <linux/kernel.h>
> +#include <linux/pci.h>
> +
> +/*
> + * Local Management Registers
> + */
> +#define CDNS_PCIE_LM_BASE	0x00100000
> +
> +/* Vendor ID Register */
> +#define CDNS_PCIE_LM_ID		(CDNS_PCIE_LM_BASE + 0x0044)
> +#define  CDNS_PCIE_LM_ID_VENDOR_MASK	GENMASK(15, 0)
> +#define  CDNS_PCIE_LM_ID_VENDOR_SHIFT	0
> +#define  CDNS_PCIE_LM_ID_VENDOR(vid) \
> +	(((vid) << CDNS_PCIE_LM_ID_VENDOR_SHIFT) & CDNS_PCIE_LM_ID_VENDOR_MASK)
> +#define  CDNS_PCIE_LM_ID_SUBSYS_MASK	GENMASK(31, 16)
> +#define  CDNS_PCIE_LM_ID_SUBSYS_SHIFT	16
> +#define  CDNS_PCIE_LM_ID_SUBSYS(sub) \
> +	(((sub) << CDNS_PCIE_LM_ID_SUBSYS_SHIFT) & CDNS_PCIE_LM_ID_SUBSYS_MASK)
> +
> +/* Root Port Requestor ID Register */
> +#define CDNS_PCIE_LM_RP_RID	(CDNS_PCIE_LM_BASE + 0x0228)
> +#define  CDNS_PCIE_LM_RP_RID_MASK	GENMASK(15, 0)
> +#define  CDNS_PCIE_LM_RP_RID_SHIFT	0
> +#define  CDNS_PCIE_LM_RP_RID_(rid) \
> +	(((rid) << CDNS_PCIE_LM_RP_RID_SHIFT) & CDNS_PCIE_LM_RP_RID_MASK)
> +
> +/* Endpoint Bus and Device Number Register */
> +#define CDNS_PCIE_LM_EP_ID	(CDNS_PCIE_LM_BASE + 0x022c)
> +#define  CDNS_PCIE_LM_EP_ID_DEV_MASK	GENMASK(4, 0)
> +#define  CDNS_PCIE_LM_EP_ID_DEV_SHIFT	0
> +#define  CDNS_PCIE_LM_EP_ID_BUS_MASK	GENMASK(15, 8)
> +#define  CDNS_PCIE_LM_EP_ID_BUS_SHIFT	8
> +
> +/* Endpoint Function f BAR b Configuration Registers */
> +#define CDNS_PCIE_LM_EP_FUNC_BAR_CFG0(fn) \
> +	(CDNS_PCIE_LM_BASE + 0x0240 + (fn) * 0x0008)
> +#define CDNS_PCIE_LM_EP_FUNC_BAR_CFG1(fn) \
> +	(CDNS_PCIE_LM_BASE + 0x0244 + (fn) * 0x0008)
> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b) \
> +	(GENMASK(4, 0) << ((b) * 8))
> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE(b, a) \
> +	(((a) << ((b) * 8)) & CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b))
> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b) \
> +	(GENMASK(7, 5) << ((b) * 8))
> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL(b, c) \
> +	(((c) << ((b) * 8 + 5)) & CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b))
> +
> +/* Endpoint Function Configuration Register */
> +#define CDNS_PCIE_LM_EP_FUNC_CFG	(CDNS_PCIE_LM_BASE + 0x02c0)

All endpoint defines should be moved to the patch that needs them.

> +
> +/* Root Complex BAR Configuration Register */
> +#define CDNS_PCIE_LM_RC_BAR_CFG	(CDNS_PCIE_LM_BASE + 0x0300)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_APERTURE_MASK	GENMASK(5, 0)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_APERTURE(a) \
> +	(((a) << 0) & CDNS_PCIE_LM_RC_BAR_CFG_BAR0_APERTURE_MASK)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL_MASK		GENMASK(8, 6)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(c) \
> +	(((c) << 6) & CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL_MASK)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_APERTURE_MASK	GENMASK(13, 9)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_APERTURE(a) \
> +	(((a) << 9) & CDNS_PCIE_LM_RC_BAR_CFG_BAR1_APERTURE_MASK)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL_MASK		GENMASK(16, 14)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(c) \
> +	(((c) << 14) & CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL_MASK)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE	BIT(17)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_32BITS	0
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS	BIT(18)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE		BIT(19)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_IO_16BITS		0
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS		BIT(20)
> +#define  CDNS_PCIE_LM_RC_BAR_CFG_CHECK_ENABLE		BIT(31)
> +
> +/* BAR control values applicable to both Endpoint Function and Root Complex */
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED		0x0
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_IO_32BITS		0x1
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_MEM_32BITS		0x4
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_PREFETCH_MEM_32BITS	0x5
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_MEM_64BITS		0x6
> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_PREFETCH_MEM_64BITS	0x7
> +
> +
> +/*
> + * Endpoint Function Registers (PCI configuration space for endpoint functions)
> + */
> +#define CDNS_PCIE_EP_FUNC_BASE(fn)	(((fn) << 12) & GENMASK(19, 12))
> +
> +#define CDNS_PCIE_EP_FUNC_MSI_CAP_OFFSET	0x90
> +
> +/*
> + * Root Port Registers (PCI configuration space for the root port function)
> + */
> +#define CDNS_PCIE_RP_BASE	0x00200000
> +
> +
> +/*
> + * Address Translation Registers
> + */
> +#define CDNS_PCIE_AT_BASE	0x00400000
> +
> +/* Region r Outbound AXI to PCIe Address Translation Register 0 */
> +#define CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r) \
> +	(CDNS_PCIE_AT_BASE + 0x0000 + ((r) & 0x1f) * 0x0020)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS_MASK	GENMASK(5, 0)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(nbits) \
> +	(((nbits) - 1) & CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS_MASK)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN_MASK	GENMASK(19, 12)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN(devfn) \
> +	(((devfn) << 12) & CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN_MASK)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS_MASK	GENMASK(27, 20)
> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS(bus) \
> +	(((bus) << 20) & CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS_MASK)
> +
> +/* Region r Outbound AXI to PCIe Address Translation Register 1 */
> +#define CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r) \
> +	(CDNS_PCIE_AT_BASE + 0x0004 + ((r) & 0x1f) * 0x0020)
> +
> +/* Region r Outbound PCIe Descriptor Register 0 */
> +#define CDNS_PCIE_AT_OB_REGION_DESC0(r) \
> +	(CDNS_PCIE_AT_BASE + 0x0008 + ((r) & 0x1f) * 0x0020)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_MASK		GENMASK(3, 0)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_MEM		0x2
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_IO		0x6
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE0	0xa
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE1	0xb
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_NORMAL_MSG	0xc
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_VENDOR_MSG	0xd
> +/* Bit 23 MUST be set in RC mode. */
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID	BIT(23)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN_MASK	GENMASK(31, 24)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(devfn) \
> +	(((devfn) << 24) & CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN_MASK)
> +
> +/* Region r Outbound PCIe Descriptor Register 1 */
> +#define CDNS_PCIE_AT_OB_REGION_DESC1(r)	\
> +	(CDNS_PCIE_AT_BASE + 0x000c + ((r) & 0x1f) * 0x0020)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC1_BUS_MASK	GENMASK(7, 0)
> +#define  CDNS_PCIE_AT_OB_REGION_DESC1_BUS(bus) \
> +	((bus) & CDNS_PCIE_AT_OB_REGION_DESC1_BUS_MASK)
> +
> +/* Region r AXI Region Base Address Register 0 */
> +#define CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r) \
> +	(CDNS_PCIE_AT_BASE + 0x0018 + ((r) & 0x1f) * 0x0020)
> +#define  CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS_MASK	GENMASK(5, 0)
> +#define  CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(nbits) \
> +	(((nbits) - 1) & CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS_MASK)
> +
> +/* Region r AXI Region Base Address Register 1 */
> +#define CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r) \
> +	(CDNS_PCIE_AT_BASE + 0x001c + ((r) & 0x1f) * 0x0020)
> +
> +/* Root Port BAR Inbound PCIe to AXI Address Translation Register */
> +#define CDNS_PCIE_AT_IB_RP_BAR_ADDR0(bar) \
> +	(CDNS_PCIE_AT_BASE + 0x0800 + (bar) * 0x0008)
> +#define  CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS_MASK	GENMASK(5, 0)
> +#define  CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS(nbits) \
> +	(((nbits) - 1) & CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS_MASK)
> +#define CDNS_PCIE_AT_IB_RP_BAR_ADDR1(bar) \
> +	(CDNS_PCIE_AT_BASE + 0x0804 + (bar) * 0x0008)
> +
> +enum cdns_pcie_rp_bar {
> +	RP_BAR0,
> +	RP_BAR1,
> +	RP_NO_BAR
> +};
> +
> +/* Endpoint Function BAR Inbound PCIe to AXI Address Translation Register */
> +#define CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR0(fn, bar) \
> +	(CDNS_PCIE_AT_BASE + 0x0840 + (fn) * 0x0040 + (bar) * 0x0008)
> +#define CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR1(fn, bar) \
> +	(CDNS_PCIE_AT_BASE + 0x0844 + (fn) * 0x0040 + (bar) * 0x0008)
> +
> +/* Normal/Vendor specific message access: offset inside some outbound region */
> +#define CDNS_PCIE_NORMAL_MSG_ROUTING_MASK	GENMASK(7, 5)
> +#define CDNS_PCIE_NORMAL_MSG_ROUTING(route) \
> +	(((route) << 5) & CDNS_PCIE_NORMAL_MSG_ROUTING_MASK)
> +#define CDNS_PCIE_NORMAL_MSG_CODE_MASK		GENMASK(15, 8)
> +#define CDNS_PCIE_NORMAL_MSG_CODE(code) \
> +	(((code) << 8) & CDNS_PCIE_NORMAL_MSG_CODE_MASK)
> +#define CDNS_PCIE_MSG_NO_DATA			BIT(16)
> +
> +enum cdns_pcie_msg_code {
> +	MSG_CODE_ASSERT_INTA	= 0x20,
> +	MSG_CODE_ASSERT_INTB	= 0x21,
> +	MSG_CODE_ASSERT_INTC	= 0x22,
> +	MSG_CODE_ASSERT_INTD	= 0x23,
> +	MSG_CODE_DEASSERT_INTA	= 0x24,
> +	MSG_CODE_DEASSERT_INTB	= 0x25,
> +	MSG_CODE_DEASSERT_INTC	= 0x26,
> +	MSG_CODE_DEASSERT_INTD	= 0x27,
> +};
> +
> +enum cdns_pcie_msg_routing {
> +	/* Route to Root Complex */
> +	MSG_ROUTING_TO_RC,
> +
> +	/* Use Address Routing */
> +	MSG_ROUTING_BY_ADDR,
> +
> +	/* Use ID Routing */
> +	MSG_ROUTING_BY_ID,
> +
> +	/* Route as Broadcast Message from Root Complex */
> +	MSG_ROUTING_BCAST,
> +
> +	/* Local message; terminate at receiver (INTx messages) */
> +	MSG_ROUTING_LOCAL,
> +
> +	/* Gather & route to Root Complex (PME_TO_Ack message) */
> +	MSG_ROUTING_GATHER,
> +};
> +
> +/**
> + * struct cdns_pcie - private data for Cadence PCIe controller drivers
> + * @reg_base: IO mapped register base
> + * @mem_res: start/end offsets in the physical system memory to map PCI accesses
> + * @is_rc: tell whether the PCIe controller mode is Root Complex or Endpoint.
> + * @bus: In Root Complex mode, the bus number
> + */
> +struct cdns_pcie {
> +	void __iomem		*reg_base;
> +	struct resource		*mem_res;
> +	bool			is_rc;
> +	u8			bus;
> +};
> +
> +/* Register access */
> +static inline void cdns_pcie_writeb(struct cdns_pcie *pcie, u32 reg, u8 value)
> +{
> +	writeb(value, pcie->reg_base + reg);
> +}
> +
> +static inline void cdns_pcie_writew(struct cdns_pcie *pcie, u32 reg, u16 value)
> +{
> +	writew(value, pcie->reg_base + reg);
> +}
> +
> +static inline void cdns_pcie_writel(struct cdns_pcie *pcie, u32 reg, u32 value)
> +{
> +	writel(value, pcie->reg_base + reg);
> +}
> +
> +static inline u32 cdns_pcie_readl(struct cdns_pcie *pcie, u32 reg)
> +{
> +	return readl(pcie->reg_base + reg);
> +}
> +
> +/* Root Port register access */
> +static inline void cdns_pcie_rp_writeb(struct cdns_pcie *pcie,
> +				       u32 reg, u8 value)
> +{
> +	writeb(value, pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
> +}
> +
> +static inline void cdns_pcie_rp_writew(struct cdns_pcie *pcie,
> +				       u32 reg, u16 value)
> +{
> +	writew(value, pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
> +}
> +
> +/* Endpoint Function register access */
> +static inline void cdns_pcie_ep_fn_writeb(struct cdns_pcie *pcie, u8 fn,
> +					  u32 reg, u8 value)
> +{
> +	writeb(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}
> +
> +static inline void cdns_pcie_ep_fn_writew(struct cdns_pcie *pcie, u8 fn,
> +					  u32 reg, u16 value)
> +{
> +	writew(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}
> +
> +static inline void cdns_pcie_ep_fn_writel(struct cdns_pcie *pcie, u8 fn,
> +					  u32 reg, u16 value)
> +{
> +	writel(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}
> +
> +static inline u8 cdns_pcie_ep_fn_readb(struct cdns_pcie *pcie, u8 fn, u32 reg)
> +{
> +	return readb(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}
> +
> +static inline u16 cdns_pcie_ep_fn_readw(struct cdns_pcie *pcie, u8 fn, u32 reg)
> +{
> +	return readw(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}
> +
> +static inline u32 cdns_pcie_ep_fn_readl(struct cdns_pcie *pcie, u8 fn, u32 reg)
> +{
> +	return readl(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
> +}

Same comments for all endpoint related functions and defines above.

Thanks,
Lorenzo

> +void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u32 r, bool is_io,
> +				   u64 cpu_addr, u64 pci_addr, size_t size);
> +
> +void cdns_pcie_set_outbound_region_for_normal_msg(struct cdns_pcie *pcie, u32 r,
> +						  u64 cpu_addr);
> +
> +void cdns_pcie_reset_outbound_region(struct cdns_pcie *pcie, u32 r);
> +
> +#endif /* _PCIE_CADENCE_H */
> -- 
> 2.11.0
>

On Wed, Nov 29, 2017 at 06:25:15PM +0000, Lorenzo Pieralisi wrote:

[...]

> static void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
> 				      int where)
> 
> > +cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn, int where)
> > +{
> > +	struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
> > +	struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
> > +	struct cdns_pcie *pcie = &rc->pcie;
> > +	unsigned int busn = bus->number;
> > +	u32 addr0, desc0;
> > +
> > +	if (busn < rc->bus_range->start || busn > rc->bus_range->end)
> > +		return NULL;
> 
> It does not hurt but I wonder whether you really need this check.
> 
> > +	if (busn == rc->bus_range->start) {
> > +		if (devfn)
> 
> I suspect I know why you need this check but I ask you to explain it
> anyway if you do not mind please.
> 
> > +			return NULL;
> > +
> > +		return pcie->reg_base + (where & 0xfff);
> > +	}
> > +
> > +	/* Update Output registers for AXI region 0. */
> > +	addr0 = CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(12) |
> 
> Ok, so for every config access you reprogram addr0 to reflect the
> correct bus|devfn ID in the PCI bus TLP corresponding to an ECAM address
> in CPU physical address space, is my understanding correct ?

By re-reading it, it looks like this mechanism is there to just
associate a different RID TLP on the PCI bus to a fixed window
in CPU virtual address space.

> > +		CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN(devfn) |
> > +		CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS(busn);
> > +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(0), addr0);
> > +
> > +	/* Configuration Type 0 or Type 1 access. */
> > +	desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
> > +		CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
> > +	/*
> > +	 * The bus number was already set once for all in desc1 by
> > +	 * cdns_pcie_host_init_address_translation().
> > +	 */
> > +	if (busn == rc->bus_range->start + 1)
> > +		desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE0;
> > +	else
> > +		desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE1;
> 
> I would like to ask you why you have to do it here and the root port
> does not figure it out by itself, I do not have the datasheet so I am
> just asking for my own information.
> 
> > +	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(0), desc0);
> > +
> > +	return rc->cfg_base + (where & 0xfff);
> > +}

[...]

> > +static int cdns_pcie_host_init(struct device *dev,
> > +			       struct list_head *resources,
> > +			       struct cdns_pcie_rc *rc)
> > +{
> > +	struct resource *bus_range = NULL;
> > +	int err;
> > +
> > +	/* Parse our PCI ranges and request their resources */
> > +	err = cdns_pcie_parse_request_of_pci_ranges(dev, resources, &bus_range);
> > +	if (err)
> > +		goto err_out;
> 
> I think that the err_out path should be part of:
> 
> cdns_pcie_parse_request_of_pci_ranges()
> 
> implementation and here you would just return.

I take it back, what you are doing is cleaner and allows you to
have code freeing the resource list in one single place so you
can leave this as-is.

Thanks,
Lorenzo

Hi Bjorn,

Le 28/11/2017 à 21:41, Bjorn Helgaas a écrit :
> On Thu, Nov 23, 2017 at 04:01:48PM +0100, Cyrille Pitchen wrote:
>> This patch adds support to the Cadence PCIe controller in host mode.
>>
>> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
>> ---
>>  drivers/Makefile                        |   1 +
>>  drivers/pci/Kconfig                     |   1 +
>>  drivers/pci/cadence/Kconfig             |  24 ++
>>  drivers/pci/cadence/Makefile            |   2 +
>>  drivers/pci/cadence/pcie-cadence-host.c | 425 ++++++++++++++++++++++++++++++++
>>  drivers/pci/cadence/pcie-cadence.c      | 110 +++++++++
>>  drivers/pci/cadence/pcie-cadence.h      | 325 ++++++++++++++++++++++++
>>  7 files changed, 888 insertions(+)
>>  create mode 100644 drivers/pci/cadence/Kconfig
>>  create mode 100644 drivers/pci/cadence/Makefile
>>  create mode 100644 drivers/pci/cadence/pcie-cadence-host.c
>>  create mode 100644 drivers/pci/cadence/pcie-cadence.c
>>  create mode 100644 drivers/pci/cadence/pcie-cadence.h
> 
> I prefer a single file per driver.  I assume you're anticipating
> something like dwc, where the DesignWare core is incorporated into
> several devices in slightly different ways.  But it doesn't look like
> that's here yet, and personally, I'd rather split out the required
> things when they actually become required, not ahead of time.
>

The source code in pcie-cadence.c is shared between pcie-cadence-host.c
(Root Complex mode) and pcie-cadence-ep.c (Endpoint mode), the second
driver of this series.

Taking other comments into accounts, I will move endpoint only related
stuff in the pcie-cadence.{c,h} files from this patch to the endpoint
patch.

Otherwise your right, I expect this Cadence PCIe core to be embedded inside
several vendor SoCs but I thought I could handle this as much as possible
using mainly DT properties and/or the 'struct cdns_pcie_*_data' associated
to the DT 'compatible' strings. We will have to wait for those SoCs to be
released to know whether these two solutions are  enough or if we will need
dedicated files anyway.
 
>> diff --git a/drivers/Makefile b/drivers/Makefile
>> index 1d034b680431..27bdd98784d9 100644
>> --- a/drivers/Makefile
>> +++ b/drivers/Makefile
>> @@ -18,6 +18,7 @@ obj-y				+= pwm/
>>  
>>  obj-$(CONFIG_PCI)		+= pci/
>>  obj-$(CONFIG_PCI_ENDPOINT)	+= pci/endpoint/
>> +obj-$(CONFIG_PCI_CADENCE)	+= pci/cadence/
> 
> I can't remember why we added CONFIG_PCI_ENDPOINT here instead of in
> drivers/pci/Makefile.  Is there any way to move both CONFIG_PCI_ENDPOINT
> and CONFIG_PCI_CADENCE into drivers/pci/Makefile so this is better
> encapsulated?
>

I will work on the solution I have proposed in another reply since it seems
to be OK for you :)

>>  # PCI dwc controller drivers
>>  obj-y				+= pci/dwc/
>> ...
> 
>> + * struct cdns_pcie_rc_data - hardware specific data
> 
> "cdns" is a weird abbreviation for "Cadence", since "Cadence" doesn't
> contain an "s".
> 
>> ...
>> +static int cdns_pcie_parse_request_of_pci_ranges(struct device *dev,
>> +						 struct list_head *resources,
>> +						 struct resource **bus_range)
>> +{
>> +	int err, res_valid = 0;
>> +	struct device_node *np = dev->of_node;
>> +	resource_size_t iobase;
>> +	struct resource_entry *win, *tmp;
>> +
>> +	err = of_pci_get_host_bridge_resources(np, 0, 0xff, resources, &iobase);
>> +	if (err)
>> +		return err;
>> +
>> +	err = devm_request_pci_bus_resources(dev, resources);
>> +	if (err)
>> +		return err;
>> +
>> +	resource_list_for_each_entry_safe(win, tmp, resources) {
>> +		struct resource *res = win->res;
>> +
>> +		switch (resource_type(res)) {
>> +		case IORESOURCE_IO:
>> +			err = pci_remap_iospace(res, iobase);
>> +			if (err) {
>> +				dev_warn(dev, "error %d: failed to map resource %pR\n",
>> +					 err, res);
>> +				resource_list_destroy_entry(win);
>> +			}
>> +			break;
>> +		case IORESOURCE_MEM:
>> +			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
>> +			break;
>> +		case IORESOURCE_BUS:
>> +			*bus_range = res;
>> +			break;
>> +		}
>> +	}
>> +
>> +	if (res_valid)
>> +		return 0;
>> +
>> +	dev_err(dev, "non-prefetchable memory resource required\n");
>> +	return -EINVAL;
>> +}
> 
> The code above is starting to look awfully familiar.  I wonder if it's
> time to think about some PCI-internal interface that can encapsulate
> this.  In this case, there's really nothing Cadence-specific here.
> There are other callers where there *is* vendor-specific code, but
> possibly that could be handled by returning pointers to bus number,
> I/O port, and MMIO resources so the caller could do the
> vendor-specific stuff?
> 
> Bjorn
> 

I am listing:
- gen_pci_parse_request_of_pci_ranges() [1]
- cdns_pcie_parse_request_of_pci_ranges() - same as [1]
- advk_pcie_parse_request_of_pci_ranges()
- altera_pcie_parse_request_of_pci_ranges()
- versatile_pci_parse_request_of_pci_ranges()
- rcar_pcie_parse_request_of_pci_ranges()

Then what about doing something like that:

---8<--------------------------------------------------------------------------
diff --git a/drivers/pci/host/pci-host-common.c b/drivers/pci/host/pci-host-common.c
index 44a47d4f0b8f..2413c5d83cbd 100644
--- a/drivers/pci/host/pci-host-common.c
+++ b/drivers/pci/host/pci-host-common.c
@@ -24,10 +24,19 @@
 #include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
 
-static int gen_pci_parse_request_of_pci_ranges(struct device *dev,
-		       struct list_head *resources, struct resource **bus_range)
+struct pci_host_resource_parser {
+	int	(*get_resource)(void *userdata, struct resource_entry *win,
+				resource_size_t iobase);
+	int	(*finalize)(void *userdata);
+	void	(*abort)(void *userdata);
+};
+
+int pci_host_parse_request_of_pci_ranges(struct device *dev,
+				 struct list_head *resources,
+				 const struct pci_host_resource_parser *parser,
+				 void *userdata)
 {
-	int err, res_valid = 0;
+	int err;
 	struct device_node *np = dev->of_node;
 	resource_size_t iobase;
 	struct resource_entry *win, *tmp;
@@ -40,34 +49,94 @@ static int gen_pci_parse_request_of_pci_ranges(struct device *dev,
 	if (err)
 		return err;
 
-	resource_list_for_each_entry_safe(win, tmp, resources) {
-		struct resource *res = win->res;
-
-		switch (resource_type(res)) {
-		case IORESOURCE_IO:
-			err = pci_remap_iospace(res, iobase);
-			if (err) {
-				dev_warn(dev, "error %d: failed to map resource %pR\n",
-					 err, res);
-				resource_list_destroy_entry(win);
-			}
-			break;
-		case IORESOURCE_MEM:
-			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
-			break;
-		case IORESOURCE_BUS:
-			*bus_range = res;
-			break;
+	if (parser && parser->get_resource) {
+		resource_list_for_each_entry_safe(win, tmp, resources) {
+			err = parser->get_resource(userdata, win, iobase);
+			if (err)
+				goto do_abort;
+		}
+	}
+
+	if (parser && parser->finalize)
+		return parser->finalize(userdata);
+
+	return 0;
+
+ do_abort:
+	if (parser && parser->abort)
+		parser->abort(userdata);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(pci_host_parse_request_of_pci_ranges);
+
+
+struct gen_pci_parser_context {
+	struct device	*dev;
+	struct resource	**bus_range;
+	int		res_valid;
+};
+
+static int gen_pci_resource_parser_get_resource(void *userdata,
+						struct resource_entry *win,
+						resource_size_t iobase)
+{
+	struct gen_pci_parser_context *ctx = userdata;
+	struct device *dev = ctx->dev;
+	struct resource *res = win->res;
+	int err;
+
+	switch (resource_type(res)) {
+	case IORESOURCE_IO:
+		err = pci_remap_iospace(res, iobase);
+		if (err) {
+			dev_warn(dev, "error %d: failed to map resource %pR\n",
+				 err, res);
+			resource_list_destroy_entry(win);
 		}
+		break;
+	case IORESOURCE_MEM:
+		ctx->res_valid |= !(res->flags & IORESOURCE_PREFETCH);
+		break;
+	case IORESOURCE_BUS:
+		*ctx->bus_range = res;
+		break;
 	}
 
-	if (res_valid)
+	return 0;
+}
+
+static int gen_pci_resource_parser_finalize(void *userdata)
+{
+	struct gen_pci_parser_context *ctx = userdata;
+	struct device *dev = ctx->dev;
+
+	if (ctx->res_valid)
 		return 0;
 
 	dev_err(dev, "non-prefetchable memory resource required\n");
 	return -EINVAL;
 }
 
+static const struct pci_host_resource_parser gen_pci_resource_parser = {
+	.get_resource	= gen_pci_resource_parser_get_resource,
+	.finalize	= gen_pci_resource_parser_finalize,
+};
+
+static int gen_pci_parse_request_of_pci_ranges(struct device *dev,
+		       struct list_head *resources, struct resource **bus_range)
+{
+	struct gen_pci_parser_context ctx;
+
+	ctx.dev = dev;
+	ctx.bus_range = bus_range;
+	ctx.res_valid = 0;
+
+	return pci_host_parse_request_of_pci_ranges(dev, resources,
+						    &gen_pci_resource_parser,
+						    &ctx);
+}
+
 static void gen_pci_unmap_cfg(void *ptr)
 {
 	pci_ecam_free((struct pci_config_window *)ptr);
---8<--------------------------------------------------------------------------

Best regards,

Cyrille

On Fri, Dec 01, 2017 at 11:37:49AM +0100, Cyrille Pitchen wrote:
> Hi Bjorn,
> 
> Le 28/11/2017 à 21:41, Bjorn Helgaas a écrit :
> > On Thu, Nov 23, 2017 at 04:01:48PM +0100, Cyrille Pitchen wrote:
> >> This patch adds support to the Cadence PCIe controller in host mode.
> >>
> >> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
> >> ---
> >>  drivers/Makefile                        |   1 +
> >>  drivers/pci/Kconfig                     |   1 +
> >>  drivers/pci/cadence/Kconfig             |  24 ++
> >>  drivers/pci/cadence/Makefile            |   2 +
> >>  drivers/pci/cadence/pcie-cadence-host.c | 425 ++++++++++++++++++++++++++++++++
> >>  drivers/pci/cadence/pcie-cadence.c      | 110 +++++++++
> >>  drivers/pci/cadence/pcie-cadence.h      | 325 ++++++++++++++++++++++++
> >>  7 files changed, 888 insertions(+)
> >>  create mode 100644 drivers/pci/cadence/Kconfig
> >>  create mode 100644 drivers/pci/cadence/Makefile
> >>  create mode 100644 drivers/pci/cadence/pcie-cadence-host.c
> >>  create mode 100644 drivers/pci/cadence/pcie-cadence.c
> >>  create mode 100644 drivers/pci/cadence/pcie-cadence.h
> > 
> > I prefer a single file per driver.  I assume you're anticipating
> > something like dwc, where the DesignWare core is incorporated into
> > several devices in slightly different ways.  But it doesn't look like
> > that's here yet, and personally, I'd rather split out the required
> > things when they actually become required, not ahead of time.
> >
> 
> The source code in pcie-cadence.c is shared between pcie-cadence-host.c
> (Root Complex mode) and pcie-cadence-ep.c (Endpoint mode), the second
> driver of this series.
> 
> Taking other comments into accounts, I will move endpoint only related
> stuff in the pcie-cadence.{c,h} files from this patch to the endpoint
> patch.
> 
> Otherwise your right, I expect this Cadence PCIe core to be embedded inside
> several vendor SoCs but I thought I could handle this as much as possible
> using mainly DT properties and/or the 'struct cdns_pcie_*_data' associated
> to the DT 'compatible' strings. We will have to wait for those SoCs to be
> released to know whether these two solutions are  enough or if we will need
> dedicated files anyway.
>  
> >> diff --git a/drivers/Makefile b/drivers/Makefile
> >> index 1d034b680431..27bdd98784d9 100644
> >> --- a/drivers/Makefile
> >> +++ b/drivers/Makefile
> >> @@ -18,6 +18,7 @@ obj-y				+= pwm/
> >>  
> >>  obj-$(CONFIG_PCI)		+= pci/
> >>  obj-$(CONFIG_PCI_ENDPOINT)	+= pci/endpoint/
> >> +obj-$(CONFIG_PCI_CADENCE)	+= pci/cadence/
> > 
> > I can't remember why we added CONFIG_PCI_ENDPOINT here instead of in
> > drivers/pci/Makefile.  Is there any way to move both CONFIG_PCI_ENDPOINT
> > and CONFIG_PCI_CADENCE into drivers/pci/Makefile so this is better
> > encapsulated?
> >
> 
> I will work on the solution I have proposed in another reply since it seems
> to be OK for you :)
> 
> >>  # PCI dwc controller drivers
> >>  obj-y				+= pci/dwc/
> >> ...
> > 
> >> + * struct cdns_pcie_rc_data - hardware specific data
> > 
> > "cdns" is a weird abbreviation for "Cadence", since "Cadence" doesn't
> > contain an "s".
> > 
> >> ...
> >> +static int cdns_pcie_parse_request_of_pci_ranges(struct device *dev,
> >> +						 struct list_head *resources,
> >> +						 struct resource **bus_range)
> >> +{
> >> +	int err, res_valid = 0;
> >> +	struct device_node *np = dev->of_node;
> >> +	resource_size_t iobase;
> >> +	struct resource_entry *win, *tmp;
> >> +
> >> +	err = of_pci_get_host_bridge_resources(np, 0, 0xff, resources, &iobase);
> >> +	if (err)
> >> +		return err;
> >> +
> >> +	err = devm_request_pci_bus_resources(dev, resources);
> >> +	if (err)
> >> +		return err;
> >> +
> >> +	resource_list_for_each_entry_safe(win, tmp, resources) {
> >> +		struct resource *res = win->res;
> >> +
> >> +		switch (resource_type(res)) {
> >> +		case IORESOURCE_IO:
> >> +			err = pci_remap_iospace(res, iobase);
> >> +			if (err) {
> >> +				dev_warn(dev, "error %d: failed to map resource %pR\n",
> >> +					 err, res);
> >> +				resource_list_destroy_entry(win);
> >> +			}
> >> +			break;
> >> +		case IORESOURCE_MEM:
> >> +			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
> >> +			break;
> >> +		case IORESOURCE_BUS:
> >> +			*bus_range = res;
> >> +			break;
> >> +		}
> >> +	}
> >> +
> >> +	if (res_valid)
> >> +		return 0;
> >> +
> >> +	dev_err(dev, "non-prefetchable memory resource required\n");
> >> +	return -EINVAL;
> >> +}
> > 
> > The code above is starting to look awfully familiar.  I wonder if it's
> > time to think about some PCI-internal interface that can encapsulate
> > this.  In this case, there's really nothing Cadence-specific here.
> > There are other callers where there *is* vendor-specific code, but
> > possibly that could be handled by returning pointers to bus number,
> > I/O port, and MMIO resources so the caller could do the
> > vendor-specific stuff?
> > 
> > Bjorn
> > 
> 
> I am listing:
> - gen_pci_parse_request_of_pci_ranges() [1]
> - cdns_pcie_parse_request_of_pci_ranges() - same as [1]
> - advk_pcie_parse_request_of_pci_ranges()
> - altera_pcie_parse_request_of_pci_ranges()
> - versatile_pci_parse_request_of_pci_ranges()
> - rcar_pcie_parse_request_of_pci_ranges()
> 
> Then what about doing something like that:
> 
> ---8<--------------------------------------------------------------------------
> diff --git a/drivers/pci/host/pci-host-common.c b/drivers/pci/host/pci-host-common.c
> index 44a47d4f0b8f..2413c5d83cbd 100644
> --- a/drivers/pci/host/pci-host-common.c
> +++ b/drivers/pci/host/pci-host-common.c
> @@ -24,10 +24,19 @@
>  #include <linux/pci-ecam.h>
>  #include <linux/platform_device.h>
>  
> -static int gen_pci_parse_request_of_pci_ranges(struct device *dev,
> -		       struct list_head *resources, struct resource **bus_range)
> +struct pci_host_resource_parser {
> +	int	(*get_resource)(void *userdata, struct resource_entry *win,
> +				resource_size_t iobase);
> +	int	(*finalize)(void *userdata);
> +	void	(*abort)(void *userdata);
> +};
> +
> +int pci_host_parse_request_of_pci_ranges(struct device *dev,
> +				 struct list_head *resources,
> +				 const struct pci_host_resource_parser *parser,
> +				 void *userdata)
>  {
> -	int err, res_valid = 0;
> +	int err;
>  	struct device_node *np = dev->of_node;
>  	resource_size_t iobase;
>  	struct resource_entry *win, *tmp;
> @@ -40,34 +49,94 @@ static int gen_pci_parse_request_of_pci_ranges(struct device *dev,
>  	if (err)
>  		return err;
>  
> -	resource_list_for_each_entry_safe(win, tmp, resources) {
> -		struct resource *res = win->res;
> -
> -		switch (resource_type(res)) {
> -		case IORESOURCE_IO:
> -			err = pci_remap_iospace(res, iobase);
> -			if (err) {
> -				dev_warn(dev, "error %d: failed to map resource %pR\n",
> -					 err, res);
> -				resource_list_destroy_entry(win);
> -			}
> -			break;
> -		case IORESOURCE_MEM:
> -			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
> -			break;
> -		case IORESOURCE_BUS:
> -			*bus_range = res;
> -			break;
> +	if (parser && parser->get_resource) {
> +		resource_list_for_each_entry_safe(win, tmp, resources) {
> +			err = parser->get_resource(userdata, win, iobase);
> +			if (err)
> +				goto do_abort;
> +		}
> +	}
> +
> +	if (parser && parser->finalize)
> +		return parser->finalize(userdata);
> +
> +	return 0;
> +
> + do_abort:
> +	if (parser && parser->abort)
> +		parser->abort(userdata);
> +
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(pci_host_parse_request_of_pci_ranges);
> +
> +
> +struct gen_pci_parser_context {
> +	struct device	*dev;
> +	struct resource	**bus_range;
> +	int		res_valid;
> +};
> +
> +static int gen_pci_resource_parser_get_resource(void *userdata,
> +						struct resource_entry *win,
> +						resource_size_t iobase)
> +{
> +	struct gen_pci_parser_context *ctx = userdata;
> +	struct device *dev = ctx->dev;
> +	struct resource *res = win->res;
> +	int err;
> +
> +	switch (resource_type(res)) {
> +	case IORESOURCE_IO:
> +		err = pci_remap_iospace(res, iobase);
> +		if (err) {
> +			dev_warn(dev, "error %d: failed to map resource %pR\n",
> +				 err, res);
> +			resource_list_destroy_entry(win);
>  		}
> +		break;
> +	case IORESOURCE_MEM:
> +		ctx->res_valid |= !(res->flags & IORESOURCE_PREFETCH);
> +		break;
> +	case IORESOURCE_BUS:
> +		*ctx->bus_range = res;
> +		break;
>  	}
>  
> -	if (res_valid)
> +	return 0;
> +}
> +
> +static int gen_pci_resource_parser_finalize(void *userdata)
> +{
> +	struct gen_pci_parser_context *ctx = userdata;
> +	struct device *dev = ctx->dev;
> +
> +	if (ctx->res_valid)
>  		return 0;
>  
>  	dev_err(dev, "non-prefetchable memory resource required\n");
>  	return -EINVAL;
>  }
>  
> +static const struct pci_host_resource_parser gen_pci_resource_parser = {
> +	.get_resource	= gen_pci_resource_parser_get_resource,
> +	.finalize	= gen_pci_resource_parser_finalize,
> +};
> +
> +static int gen_pci_parse_request_of_pci_ranges(struct device *dev,
> +		       struct list_head *resources, struct resource **bus_range)
> +{
> +	struct gen_pci_parser_context ctx;
> +
> +	ctx.dev = dev;
> +	ctx.bus_range = bus_range;
> +	ctx.res_valid = 0;
> +
> +	return pci_host_parse_request_of_pci_ranges(dev, resources,
> +						    &gen_pci_resource_parser,
> +						    &ctx);
> +}

I think that what you are doing is something along the lines:

acpi_dev_get_resources()

and the struct res_proc_context but maybe we can do something
simpler to start with.

We can go through the resource list twice in every driver, once through
the generic function that we are creating - that embeds code common
across bridges - to be clear something like:

static int of_pci_parse_request_pci_resources(struct device *dev,
					      struct list_head *res)
{
	int err, res_valid;
	resource_size_t iobase;
	struct device_node *np = dev->of_node;
	struct resource_entry *win, *tmp;

	err = of_pci_get_host_bridge_resources(np, 0, 0xff, res, &iobase);
	if (err)
		return err;

	err = devm_request_pci_bus_resources(dev, res);
	if (err)
		goto out_release_res;

	resource_list_for_each_entry_safe(win, tmp, res) {
		struct resource *res = win->res;

		switch (resource_type(res)) {
		case IORESOURCE_IO:
			err = pci_remap_iospace(res, iobase);
			if (err) {
				dev_warn(dev, "error %d: failed to map resource %pR\n",
					 err, res);
				resource_list_destroy_entry(win);
			}
			break;
		case IORESOURCE_MEM:
			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
			break;
		}
	}

	if (res_valid)
		return 0;

	dev_err(dev, "non-prefetchable memory resource required\n");
	err = -EINVAL;

out_release_res:
	pci_free_resource_list(res);
	return err;
}

and then in a PCI host bridge specific loop that just carries
out the host bridge specific actions for every resource returned
in the res list.

Lorenzo

> +
>  static void gen_pci_unmap_cfg(void *ptr)
>  {
>  	pci_ecam_free((struct pci_config_window *)ptr);
> ---8<--------------------------------------------------------------------------

Hi Lorenzo,

Le 29/11/2017 à 18:34, Lorenzo Pieralisi a écrit :
> On Thu, Nov 23, 2017 at 04:01:48PM +0100, Cyrille Pitchen wrote:
>> This patch adds support to the Cadence PCIe controller in host mode.
> 
> Bjorn already commented on this, it would be good to add some
> of the cover letter details in this log.
> 
>> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
>> ---
>>  drivers/Makefile                        |   1 +
>>  drivers/pci/Kconfig                     |   1 +
>>  drivers/pci/cadence/Kconfig             |  24 ++
>>  drivers/pci/cadence/Makefile            |   2 +
>>  drivers/pci/cadence/pcie-cadence-host.c | 425 ++++++++++++++++++++++++++++++++
> 
> You should also update the MAINTAINERS file.

I will ask Cadence who will be the maintainer.

> 
>>  drivers/pci/cadence/pcie-cadence.c      | 110 +++++++++
>>  drivers/pci/cadence/pcie-cadence.h      | 325 ++++++++++++++++++++++++
>>  7 files changed, 888 insertions(+)
>>  create mode 100644 drivers/pci/cadence/Kconfig
>>  create mode 100644 drivers/pci/cadence/Makefile
>>  create mode 100644 drivers/pci/cadence/pcie-cadence-host.c
>>  create mode 100644 drivers/pci/cadence/pcie-cadence.c
>>  create mode 100644 drivers/pci/cadence/pcie-cadence.h
>>
>> diff --git a/drivers/Makefile b/drivers/Makefile
>> index 1d034b680431..27bdd98784d9 100644
>> --- a/drivers/Makefile
>> +++ b/drivers/Makefile
>> @@ -18,6 +18,7 @@ obj-y                               += pwm/
>>
>>  obj-$(CONFIG_PCI)            += pci/
>>  obj-$(CONFIG_PCI_ENDPOINT)   += pci/endpoint/
>> +obj-$(CONFIG_PCI_CADENCE)    += pci/cadence/
> 
> Already commented on the cover letter.
> 
>>  # PCI dwc controller drivers
>>  obj-y                                += pci/dwc/
>>
>> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
>> index 90944667ccea..2471b2e36b8b 100644
>> --- a/drivers/pci/Kconfig
>> +++ b/drivers/pci/Kconfig
>> @@ -144,6 +144,7 @@ config PCI_HYPERV
>>            PCI devices from a PCI backend to support PCI driver domains.
>>
>>  source "drivers/pci/hotplug/Kconfig"
>> +source "drivers/pci/cadence/Kconfig"
>>  source "drivers/pci/dwc/Kconfig"
>>  source "drivers/pci/host/Kconfig"
>>  source "drivers/pci/endpoint/Kconfig"
>> diff --git a/drivers/pci/cadence/Kconfig b/drivers/pci/cadence/Kconfig
>> new file mode 100644
>> index 000000000000..120306cae2aa
>> --- /dev/null
>> +++ b/drivers/pci/cadence/Kconfig
>> @@ -0,0 +1,24 @@
>> +menuconfig PCI_CADENCE
>> +     bool "Cadence PCI controllers support"
>> +     depends on PCI && HAS_IOMEM
>> +     help
>> +       Say Y here if you want to support some Cadence PCI controller.
>> +
>> +       When in doubt, say N.
>> +
>> +if PCI_CADENCE
>> +
>> +config PCIE_CADENCE
>> +     bool
>> +
>> +config PCIE_CADENCE_HOST
>> +     bool "Cadence PCIe host controller"
>> +     depends on OF
>> +     depends on PCI_MSI_IRQ_DOMAIN
> 
> I do not see the reason for this dependency in the code.
>

I will remove it if it's not needed.
 
>> +     select PCIE_CADENCE
>> +     help
>> +       Say Y here if you want to support the Cadence PCIe controller in host
>> +       mode. This PCIe controller may be embedded into many different vendors
>> +       SoCs.
>> +
>> +endif # PCI_CADENCE
>> diff --git a/drivers/pci/cadence/Makefile b/drivers/pci/cadence/Makefile
>> new file mode 100644
>> index 000000000000..d57d192d2595
>> --- /dev/null
>> +++ b/drivers/pci/cadence/Makefile
>> @@ -0,0 +1,2 @@
>> +obj-$(CONFIG_PCIE_CADENCE) += pcie-cadence.o
>> +obj-$(CONFIG_PCIE_CADENCE_HOST) += pcie-cadence-host.o
>> diff --git a/drivers/pci/cadence/pcie-cadence-host.c b/drivers/pci/cadence/pcie-cadence-host.c
>> new file mode 100644
>> index 000000000000..252471e72a93
>> --- /dev/null
>> +++ b/drivers/pci/cadence/pcie-cadence-host.c
>> @@ -0,0 +1,425 @@
>> +/*
>> + * Cadence PCIe host controller driver.
>> + *
>> + * Copyright (c) 2017 Cadence
>> + *
>> + * Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License along with
>> + * this program.  If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +#include <linux/kernel.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_pci.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_runtime.h>
>> +
>> +#include "pcie-cadence.h"
>> +
>> +/**
>> + * struct cdns_pcie_rc_data - hardware specific data
>> + * @max_regions: maximum number of regions supported by the hardware
>> + * @vendor_id: PCI vendor ID
>> + * @device_id: PCI device ID
>> + * @no_bar_nbits: Number of bits to keep for inbound (PCIe -> CPU) address
>> + *                translation (nbits sets into the "no BAR match" register).
>> + */
>> +struct cdns_pcie_rc_data {
>> +     size_t                  max_regions;
> 
> Reason for it to be size_t ?
>

No special reason, I can use another integer type.
 
>> +     u16                     vendor_id;
>> +     u16                     device_id;
>> +     u8                      no_bar_nbits;
>> +};
> 
> I think that this data should come from DT (?) more below.
>

I can update the DT bindings documentation and the driver source code as needed.
 
>> +
>> +/**
>> + * struct cdns_pcie_rc - private data for this PCIe Root Complex driver
>> + * @pcie: Cadence PCIe controller
>> + * @dev: pointer to PCIe device
>> + * @cfg_res: start/end offsets in the physical system memory to map PCI
>> + *           configuration space accesses
>> + * @bus_range: first/last buses behind the PCIe host controller
>> + * @cfg_base: IO mapped window to access the PCI configuration space of a
>> + *            single function at a time
>> + * @data: pointer to a 'struct cdns_pcie_rc_data'
>> + */
>> +struct cdns_pcie_rc {
>> +     struct cdns_pcie        pcie;
>> +     struct device           *dev;
>> +     struct resource         *cfg_res;
>> +     struct resource         *bus_range;
>> +     void __iomem            *cfg_base;
>> +     const struct cdns_pcie_rc_data  *data;
>> +};
>> +
>> +static void __iomem *
> 
> Please do not split lines like this, storage class and return type
> should be in the same line as the name, move parameter(s) to a new
> line.
> 
> static void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
>                                       int where)
>

ok :)
 
>> +cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn, int where)
>> +{
>> +     struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
>> +     struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
>> +     struct cdns_pcie *pcie = &rc->pcie;
>> +     unsigned int busn = bus->number;
>> +     u32 addr0, desc0;
>> +
>> +     if (busn < rc->bus_range->start || busn > rc->bus_range->end)
>> +             return NULL;
> 
> It does not hurt but I wonder whether you really need this check.
>

I can remove it.
 
>> +     if (busn == rc->bus_range->start) {
>> +             if (devfn)
> 
> I suspect I know why you need this check but I ask you to explain it
> anyway if you do not mind please.
>

If I have understood correctly, Cadence team told me that only the root
port is available on the first bus through device 0, function 0.
No other device/function should connected on this bus, all other devices
are behind at least one PCI bridge.

I can add a comment here to explain that.
 
>> +                     return NULL;
>> +
>> +             return pcie->reg_base + (where & 0xfff);
>> +     }
>> +
>> +     /* Update Output registers for AXI region 0. */
>> +     addr0 = CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(12) |
> 
> Ok, so for every config access you reprogram addr0 to reflect the
> correct bus|devfn ID in the PCI bus TLP corresponding to an ECAM address
> in CPU physical address space, is my understanding correct ?
>

The idea is to able to use only a 4KB memory area at a fixed address in the
space allocated for the PCIe controller in the AXI bus. I guess the plan is
to leave more space on the AXI bus to map all other PCIe devices.

This is just my guess. Anyway one purpose of this driver was actually to
perform all PCI configuration space accesses through this single 4KB memory
area in the AXI bus, changing the mapping dynamically to reach the relevant
PCI device. 
 
>> +             CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN(devfn) |
>> +             CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS(busn);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(0), addr0);
>> +
>> +     /* Configuration Type 0 or Type 1 access. */
>> +     desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
>> +             CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
>> +     /*
>> +      * The bus number was already set once for all in desc1 by
>> +      * cdns_pcie_host_init_address_translation().
>> +      */
>> +     if (busn == rc->bus_range->start + 1)
>> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE0;
>> +     else
>> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE1;
> 
> I would like to ask you why you have to do it here and the root port
> does not figure it out by itself, I do not have the datasheet so I am
> just asking for my own information.

PCI configuration space registers of the root port can only be read through
the APB bus at offset 0:
->reg_base + (where & 0xfff)

They are internal registers of the PCIe controller so no TLP on the PCIe bus.

However to access the PCI configuration space registers of any other device,
the PCIe controller builds then sends a TLP on the PCIe bus using the offset
in the 4KB AXI area as the offset of the register in the PCI configuration
space:
->cfg_base + (where & 0xfff)

> 
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(0), desc0);
>> +
>> +     return rc->cfg_base + (where & 0xfff);
>> +}
>> +
>> +static struct pci_ops cdns_pcie_host_ops = {
>> +     .map_bus        = cdns_pci_map_bus,
>> +     .read           = pci_generic_config_read,
>> +     .write          = pci_generic_config_write,
>> +};
>> +
>> +static const struct cdns_pcie_rc_data cdns_pcie_rc_data = {
>> +     .max_regions    = 32,
>> +     .vendor_id      = PCI_VENDOR_ID_CDNS,
>> +     .device_id      = 0x0200,
>> +     .no_bar_nbits   = 32,
>> +};
> 
> Should (some of) these parameters be retrieved through a DT binding ?
>

Indeed, maybe we get max_regions and no_bar_nbits from the DT.

About the vendor and device IDs, I don't know which would be the best
choice between some dedicated DT properties or associating a custom
structure as above to the 'compatible' string.

Honestly, I don't have any strong preference, please just tell me what
you would prefer :)
 
>> +static const struct of_device_id cdns_pcie_host_of_match[] = {
>> +     { .compatible = "cdns,cdns-pcie-host",
>> +       .data = &cdns_pcie_rc_data },
>> +
>> +     { },
>> +};
>> +
>> +static int cdns_pcie_parse_request_of_pci_ranges(struct device *dev,
>> +                                              struct list_head *resources,
>> +                                              struct resource **bus_range)
>> +{
>> +     int err, res_valid = 0;
>> +     struct device_node *np = dev->of_node;
>> +     resource_size_t iobase;
>> +     struct resource_entry *win, *tmp;
>> +
>> +     err = of_pci_get_host_bridge_resources(np, 0, 0xff, resources, &iobase);
>> +     if (err)
>> +             return err;
>> +
>> +     err = devm_request_pci_bus_resources(dev, resources);
>> +     if (err)
>> +             return err;
>> +
>> +     resource_list_for_each_entry_safe(win, tmp, resources) {
>> +             struct resource *res = win->res;
>> +
>> +             switch (resource_type(res)) {
>> +             case IORESOURCE_IO:
>> +                     err = pci_remap_iospace(res, iobase);
>> +                     if (err) {
>> +                             dev_warn(dev, "error %d: failed to map resource %pR\n",
>> +                                      err, res);
>> +                             resource_list_destroy_entry(win);
>> +                     }
>> +                     break;
>> +             case IORESOURCE_MEM:
>> +                     res_valid |= !(res->flags & IORESOURCE_PREFETCH);
>> +                     break;
>> +             case IORESOURCE_BUS:
>> +                     *bus_range = res;
>> +                     break;
>> +             }
>> +     }
>> +
>> +     if (res_valid)
>> +             return 0;
>> +
>> +     dev_err(dev, "non-prefetchable memory resource required\n");
>> +     return -EINVAL;
> 
> Nit, I prefer you swap these two as it is done in pci-aardvark.c:
> 
>         if (!res_valid) {
>                 dev_err(dev, "non-prefetchable memory resource required\n");
>                 return -EINVAL;
>         }
> 
>         return 0;
> 
> but as per previous replies this function can be factorized in
> core PCI code - I would not bother unless you are willing to write
> the patch series that does the refactoring yourself :)
> 
>> +}
>> +
>> +static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
>> +{
>> +     const struct cdns_pcie_rc_data *data = rc->data;
>> +     struct cdns_pcie *pcie = &rc->pcie;
>> +     u8 pbn, sbn, subn;
>> +     u32 value, ctrl;
>> +
>> +     /*
>> +      * Set the root complex BAR configuration register:
>> +      * - disable both BAR0 and BAR1.
>> +      * - enable Prefetchable Memory Base and Limit registers in type 1
>> +      *   config space (64 bits).
>> +      * - enable IO Base and Limit registers in type 1 config
>> +      *   space (32 bits).
>> +      */
>> +     ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
>> +     value = CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(ctrl) |
>> +             CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(ctrl) |
>> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE |
>> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS |
>> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE |
>> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS;
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
>> +
>> +     /* Set root port configuration space */
>> +     if (data->vendor_id != 0xffff)
>> +             cdns_pcie_rp_writew(pcie, PCI_VENDOR_ID, data->vendor_id);
>> +     if (data->device_id != 0xffff)
>> +             cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, data->device_id);
>> +
>> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
>> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
>> +     cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
>> +
>> +     pbn = rc->bus_range->start;
>> +     sbn = pbn + 1; /* Single root port. */
>> +     subn = rc->bus_range->end;
>> +     cdns_pcie_rp_writeb(pcie, PCI_PRIMARY_BUS, pbn);
>> +     cdns_pcie_rp_writeb(pcie, PCI_SECONDARY_BUS, sbn);
>> +     cdns_pcie_rp_writeb(pcie, PCI_SUBORDINATE_BUS, subn);
> 
> Again - I do not have the datasheet for this device therefore I would
> kindly ask you how this works; it seems to me that what you are doing
> here is done through normal configuration cycles in an ECAM compliant
> system to program the RP PRIMARY/SECONDARY/SUBORDINATE bus - I would
> like to understand why this code is needed.
>

I will test without those lines to test whether I can remove them.

At first, the PCIe controller was tested by Cadence team: there was code
in their bootloader to initialize the hardware (building the AXI <-> PCIe
mappings, ...): the bootloader used to set the primary, secondary and
subordinate bus numbers in the root port PCI config space.

Also there was a hardware trick to redirect accesses of the lowest
addresses in the AXI bus to the APB bus so the PCI configuration space of
the root port could have been accessed from the AXI bus too.

The AXI <-> PCIe mapping being done by the bootloader and the root port
config space being accessible from the AXI bus, it was possible to use
the pci-host-generic driver.

However, the hardware trick won't be included in the final design since
Cadence now wants to perform all PCI configuration space accesses through
a small 4KB window at a fixed address on the AXI bus.
Also, we now want all initialisations to be done by the linux driver
instead of the bootloader.

I simply moved all those initialisations from the bootloader to the linux
driver but actually there is a chance that I can remove the 3 writes to
the PCI_*_BUS registers.

 
>> +     return 0;
>> +}
>> +
>> +static int cdns_pcie_host_init_address_translation(struct cdns_pcie_rc *rc)
>> +{
>> +     struct cdns_pcie *pcie = &rc->pcie;
>> +     struct resource *cfg_res = rc->cfg_res;
>> +     struct resource *mem_res = pcie->mem_res;
>> +     struct resource *bus_range = rc->bus_range;
>> +     struct device *dev = rc->dev;
>> +     struct device_node *np = dev->of_node;
>> +     struct of_pci_range_parser parser;
>> +     struct of_pci_range range;
>> +     u32 addr0, addr1, desc1;
>> +     u64 cpu_addr;
>> +     int r, err;
>> +
>> +     /*
>> +      * Reserve region 0 for PCI configure space accesses:
>> +      * OB_REGION_PCI_ADDR0 and OB_REGION_DESC0 are updated dynamically by
>> +      * cdns_pci_map_bus(), other region registers are set here once for all.
>> +      */
>> +     addr1 = 0; /* Should be programmed to zero. */
>> +     desc1 = CDNS_PCIE_AT_OB_REGION_DESC1_BUS(bus_range->start);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(0), addr1);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(0), desc1);
>> +
>> +     cpu_addr = cfg_res->start - mem_res->start;
>> +     addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(12) |
>> +             (lower_32_bits(cpu_addr) & GENMASK(31, 8));
>> +     addr1 = upper_32_bits(cpu_addr);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(0), addr0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(0), addr1);
>> +
>> +     err = of_pci_range_parser_init(&parser, np);
>> +     if (err)
>> +             return err;
>> +
>> +     r = 1;
>> +     for_each_of_pci_range(&parser, &range) {
>> +             bool is_io;
>> +
>> +             if (r >= rc->data->max_regions)
>> +                     break;
>> +
>> +             if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
>> +                     is_io = false;
>> +             else if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO)
>> +                     is_io = true;
>> +             else
>> +                     continue;
>> +
>> +             cdns_pcie_set_outbound_region(pcie, r, is_io,
>> +                                           range.cpu_addr,
>> +                                           range.pci_addr,
>> +                                           range.size);
>> +             r++;
>> +     }
>> +
>> +     /*
>> +      * Set Root Port no BAR match Inbound Translation registers:
>> +      * needed for MSI.
> 
> And DMA :) if I understand what this is doing correctly, ie setting
> the root complex decoding for incoming memory traffic.
>

Yes, indeed :)
 
>> +      * Root Port BAR0 and BAR1 are disabled, hence no need to set their
>> +      * inbound translation registers.
>> +      */
>> +     addr0 = CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS(rc->data->no_bar_nbits);
>> +     addr1 = 0;
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR0(RP_NO_BAR), addr0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_IB_RP_BAR_ADDR1(RP_NO_BAR), addr1);
>> +
>> +     return 0;
>> +}
>> +
>> +static int cdns_pcie_host_init(struct device *dev,
>> +                            struct list_head *resources,
>> +                            struct cdns_pcie_rc *rc)
>> +{
>> +     struct resource *bus_range = NULL;
>> +     int err;
>> +
>> +     /* Parse our PCI ranges and request their resources */
>> +     err = cdns_pcie_parse_request_of_pci_ranges(dev, resources, &bus_range);
>> +     if (err)
>> +             goto err_out;
> 
> I think that the err_out path should be part of:
> 
> cdns_pcie_parse_request_of_pci_ranges()
> 
> implementation and here you would just return.
> 
>> +
>> +     if (bus_range->start > bus_range->end) {
>> +             err = -EINVAL;
>> +             goto err_out;
>> +     }
> 
> Add a space here; this check seems useless to me anyway.
>

I can remove this too.
 
>> +     rc->bus_range = bus_range;
>> +     rc->pcie.bus = bus_range->start;
>> +
>> +     err = cdns_pcie_host_init_root_port(rc);
>> +     if (err)
>> +             goto err_out;
>> +
>> +     err = cdns_pcie_host_init_address_translation(rc);
>> +     if (err)
>> +             goto err_out;
>> +
>> +     return 0;
>> +
>> + err_out:
>> +     pci_free_resource_list(resources);
> 
> See above.
> 
>> +     return err;
>> +}
>> +
>> +static int cdns_pcie_host_probe(struct platform_device *pdev)
>> +{
>> +     const struct of_device_id *of_id;
>> +     const char *type;
>> +     struct device *dev = &pdev->dev;
>> +     struct device_node *np = dev->of_node;
>> +     struct pci_bus *bus, *child;
>> +     struct pci_host_bridge *bridge;
>> +     struct list_head resources;
>> +     struct cdns_pcie_rc *rc;
>> +     struct cdns_pcie *pcie;
>> +     struct resource *res;
>> +     int ret;
>> +
>> +     bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
>> +     if (!bridge)
>> +             return -ENOMEM;
>> +
>> +     rc = pci_host_bridge_priv(bridge);
>> +     rc->dev = dev;
>> +     platform_set_drvdata(pdev, rc);
> 
> I do not think it is needed.
> 
>> +     pcie = &rc->pcie;
>> +     pcie->is_rc = true;
>> +
>> +     of_id = of_match_node(cdns_pcie_host_of_match, np);
>> +     rc->data = (const struct cdns_pcie_rc_data *)of_id->data;
>> +
>> +     type = of_get_property(np, "device_type", NULL);
>> +     if (!type || strcmp(type, "pci")) {
>> +             dev_err(dev, "invalid \"device_type\" %s\n", type);
>> +             return -EINVAL;
>> +     }
>> +
>> +     res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "reg");
>> +     pcie->reg_base = devm_ioremap_resource(dev, res);
>> +     if (IS_ERR(pcie->reg_base)) {
>> +             dev_err(dev, "missing \"reg\"\n");
>> +             return PTR_ERR(pcie->reg_base);
>> +     }
>> +
>> +     res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
>> +     rc->cfg_base = devm_ioremap_resource(dev, res);
> 
> devm_pci_remap_cfg_resource() please.
>

I will change that.
 
>> +     if (IS_ERR(rc->cfg_base)) {
>> +             dev_err(dev, "missing \"cfg\"\n");
>> +             return PTR_ERR(rc->cfg_base);
>> +     }
>> +     rc->cfg_res = res;
>> +
>> +     res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem");
>> +     if (!res) {
>> +             dev_err(dev, "missing \"mem\"\n");
>> +             return -EINVAL;
>> +     }
>> +     pcie->mem_res = res;
>> +
>> +     pm_runtime_enable(dev);
>> +     ret = pm_runtime_get_sync(dev);
>> +     if (ret < 0) {
>> +             dev_err(dev, "pm_runtime_get_sync() failed\n");
>> +             goto err_get_sync;
>> +     }
>> +
>> +     INIT_LIST_HEAD(&resources);
>> +     ret = cdns_pcie_host_init(dev, &resources, rc);
>> +     if (ret)
>> +             goto err_init;
>> +
>> +     list_splice_init(&resources, &bridge->windows);
>> +     bridge->dev.parent = dev;
>> +     bridge->busnr = pcie->bus;
>> +     bridge->ops = &cdns_pcie_host_ops;
>> +     bridge->map_irq = of_irq_parse_and_map_pci;
>> +     bridge->swizzle_irq = pci_common_swizzle;
>> +
>> +     ret = pci_scan_root_bus_bridge(bridge);
>> +     if (ret < 0) {
>> +             dev_err(dev, "Scanning root bridge failed");
>> +             goto err_init;
>> +     }
>> +
>> +     bus = bridge->bus;
>> +     pci_bus_size_bridges(bus);
>> +     pci_bus_assign_resources(bus);
>> +
>> +     list_for_each_entry(child, &bus->children, node)
>> +             pcie_bus_configure_settings(child);
>> +
>> +     pci_bus_add_devices(bus);
>> +
>> +     return 0;
>> +
>> + err_init:
>> +     pm_runtime_put_sync(dev);
>> +
>> + err_get_sync:
>> +     pm_runtime_disable(dev);
>> +
>> +     return ret;
>> +}
>> +
>> +static struct platform_driver cdns_pcie_host_driver = {
>> +     .driver = {
>> +             .name = "cdns-pcie-host",
>> +             .of_match_table = cdns_pcie_host_of_match,
>> +     },
>> +     .probe = cdns_pcie_host_probe,
>> +};
>> +builtin_platform_driver(cdns_pcie_host_driver);
>> diff --git a/drivers/pci/cadence/pcie-cadence.c b/drivers/pci/cadence/pcie-cadence.c
>> new file mode 100644
>> index 000000000000..5c10879d5e96
>> --- /dev/null
>> +++ b/drivers/pci/cadence/pcie-cadence.c
>> @@ -0,0 +1,110 @@
>> +/*
>> + * Cadence PCIe controller driver.
>> + *
>> + * Copyright (c) 2017 Cadence
>> + *
>> + * Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License along with
>> + * this program.  If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#include <linux/kernel.h>
>> +
>> +#include "pcie-cadence.h"
>> +
>> +void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u32 r, bool is_io,
>> +                                u64 cpu_addr, u64 pci_addr, size_t size)
>> +{
>> +     /*
>> +      * roundup_pow_of_two() returns an unsigned long, which is not suited
>> +      * for 64bit values.
>> +      */
>> +     u64 sz = 1ULL << fls64(size - 1);
>> +     int nbits = ilog2(sz);
>> +     u32 addr0, addr1, desc0, desc1;
>> +
>> +     if (nbits < 8)
>> +             nbits = 8;
>> +
>> +     /* Set the PCI address */
>> +     addr0 = CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(nbits) |
>> +             (lower_32_bits(pci_addr) & GENMASK(31, 8));
>> +     addr1 = upper_32_bits(pci_addr);
>> +
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), addr0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), addr1);
>> +
>> +     /* Set the PCIe header descriptor */
>> +     if (is_io)
>> +             desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_IO;
>> +     else
>> +             desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_MEM;
>> +     desc1 = 0;
>> +
>> +     if (pcie->is_rc) {
>> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
>> +                      CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
>> +             desc1 |= CDNS_PCIE_AT_OB_REGION_DESC1_BUS(pcie->bus);
>> +     }
>> +
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), desc0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), desc1);
>> +
>> +     /* Set the CPU address */
>> +     cpu_addr -= pcie->mem_res->start;
>> +     addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(nbits) |
>> +             (lower_32_bits(cpu_addr) & GENMASK(31, 8));
>> +     addr1 = upper_32_bits(cpu_addr);
>> +
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), addr0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), addr1);
>> +}
>> +
>> +void cdns_pcie_set_outbound_region_for_normal_msg(struct cdns_pcie *pcie, u32 r,
>> +                                               u64 cpu_addr)
> 
> Not used in this patch, you should split it out.
> 
>> +{
>> +     u32 addr0, addr1, desc0, desc1;
>> +
>> +     desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_NORMAL_MSG;
>> +     desc1 = 0;
>> +     if (pcie->is_rc) {
>> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
>> +                      CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
>> +             desc1 |= CDNS_PCIE_AT_OB_REGION_DESC1_BUS(pcie->bus);
>> +     }
>> +
>> +     /* Set the CPU address */
>> +     cpu_addr -= pcie->mem_res->start;
>> +     addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(17) |
>> +             (lower_32_bits(cpu_addr) & GENMASK(31, 8));
>> +     addr1 = upper_32_bits(cpu_addr);
>> +
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), 0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), 0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), desc0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), desc1);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), addr0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), addr1);
>> +}
>> +
>> +void cdns_pcie_reset_outbound_region(struct cdns_pcie *pcie, u32 r)
>> +{
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), 0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), 0);
>> +
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), 0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), 0);
>> +
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), 0);
>> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), 0);
>> +}
>> diff --git a/drivers/pci/cadence/pcie-cadence.h b/drivers/pci/cadence/pcie-cadence.h
>> new file mode 100644
>> index 000000000000..195e23b7d4fe
>> --- /dev/null
>> +++ b/drivers/pci/cadence/pcie-cadence.h
>> @@ -0,0 +1,325 @@
>> +/*
>> + * Cadence PCIe controller driver.
>> + *
>> + * Copyright (c) 2017 Cadence
>> + *
>> + * Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License along with
>> + * this program.  If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#ifndef _PCIE_CADENCE_H
>> +#define _PCIE_CADENCE_H
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/pci.h>
>> +
>> +/*
>> + * Local Management Registers
>> + */
>> +#define CDNS_PCIE_LM_BASE    0x00100000
>> +
>> +/* Vendor ID Register */
>> +#define CDNS_PCIE_LM_ID              (CDNS_PCIE_LM_BASE + 0x0044)
>> +#define  CDNS_PCIE_LM_ID_VENDOR_MASK GENMASK(15, 0)
>> +#define  CDNS_PCIE_LM_ID_VENDOR_SHIFT        0
>> +#define  CDNS_PCIE_LM_ID_VENDOR(vid) \
>> +     (((vid) << CDNS_PCIE_LM_ID_VENDOR_SHIFT) & CDNS_PCIE_LM_ID_VENDOR_MASK)
>> +#define  CDNS_PCIE_LM_ID_SUBSYS_MASK GENMASK(31, 16)
>> +#define  CDNS_PCIE_LM_ID_SUBSYS_SHIFT        16
>> +#define  CDNS_PCIE_LM_ID_SUBSYS(sub) \
>> +     (((sub) << CDNS_PCIE_LM_ID_SUBSYS_SHIFT) & CDNS_PCIE_LM_ID_SUBSYS_MASK)
>> +
>> +/* Root Port Requestor ID Register */
>> +#define CDNS_PCIE_LM_RP_RID  (CDNS_PCIE_LM_BASE + 0x0228)
>> +#define  CDNS_PCIE_LM_RP_RID_MASK    GENMASK(15, 0)
>> +#define  CDNS_PCIE_LM_RP_RID_SHIFT   0
>> +#define  CDNS_PCIE_LM_RP_RID_(rid) \
>> +     (((rid) << CDNS_PCIE_LM_RP_RID_SHIFT) & CDNS_PCIE_LM_RP_RID_MASK)
>> +
>> +/* Endpoint Bus and Device Number Register */
>> +#define CDNS_PCIE_LM_EP_ID   (CDNS_PCIE_LM_BASE + 0x022c)
>> +#define  CDNS_PCIE_LM_EP_ID_DEV_MASK GENMASK(4, 0)
>> +#define  CDNS_PCIE_LM_EP_ID_DEV_SHIFT        0
>> +#define  CDNS_PCIE_LM_EP_ID_BUS_MASK GENMASK(15, 8)
>> +#define  CDNS_PCIE_LM_EP_ID_BUS_SHIFT        8
>> +
>> +/* Endpoint Function f BAR b Configuration Registers */
>> +#define CDNS_PCIE_LM_EP_FUNC_BAR_CFG0(fn) \
>> +     (CDNS_PCIE_LM_BASE + 0x0240 + (fn) * 0x0008)
>> +#define CDNS_PCIE_LM_EP_FUNC_BAR_CFG1(fn) \
>> +     (CDNS_PCIE_LM_BASE + 0x0244 + (fn) * 0x0008)
>> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b) \
>> +     (GENMASK(4, 0) << ((b) * 8))
>> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE(b, a) \
>> +     (((a) << ((b) * 8)) & CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_APERTURE_MASK(b))
>> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b) \
>> +     (GENMASK(7, 5) << ((b) * 8))
>> +#define  CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL(b, c) \
>> +     (((c) << ((b) * 8 + 5)) & CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL_MASK(b))
>> +
>> +/* Endpoint Function Configuration Register */
>> +#define CDNS_PCIE_LM_EP_FUNC_CFG     (CDNS_PCIE_LM_BASE + 0x02c0)
> 
> All endpoint defines should be moved to the patch that needs them.
>

Will move those definitions into the endpoint patch.

Thanks for the review!

Best regards,

Cyrille
 
>> +
>> +/* Root Complex BAR Configuration Register */
>> +#define CDNS_PCIE_LM_RC_BAR_CFG      (CDNS_PCIE_LM_BASE + 0x0300)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_APERTURE_MASK  GENMASK(5, 0)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_APERTURE(a) \
>> +     (((a) << 0) & CDNS_PCIE_LM_RC_BAR_CFG_BAR0_APERTURE_MASK)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL_MASK              GENMASK(8, 6)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(c) \
>> +     (((c) << 6) & CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL_MASK)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_APERTURE_MASK  GENMASK(13, 9)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_APERTURE(a) \
>> +     (((a) << 9) & CDNS_PCIE_LM_RC_BAR_CFG_BAR1_APERTURE_MASK)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL_MASK              GENMASK(16, 14)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(c) \
>> +     (((c) << 14) & CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL_MASK)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE BIT(17)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_32BITS 0
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS BIT(18)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE           BIT(19)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_IO_16BITS           0
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS           BIT(20)
>> +#define  CDNS_PCIE_LM_RC_BAR_CFG_CHECK_ENABLE                BIT(31)
>> +
>> +/* BAR control values applicable to both Endpoint Function and Root Complex */
>> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED          0x0
>> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_IO_32BITS         0x1
>> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_MEM_32BITS                0x4
>> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_PREFETCH_MEM_32BITS       0x5
>> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_MEM_64BITS                0x6
>> +#define  CDNS_PCIE_LM_BAR_CFG_CTRL_PREFETCH_MEM_64BITS       0x7
>> +
>> +
>> +/*
>> + * Endpoint Function Registers (PCI configuration space for endpoint functions)
>> + */
>> +#define CDNS_PCIE_EP_FUNC_BASE(fn)   (((fn) << 12) & GENMASK(19, 12))
>> +
>> +#define CDNS_PCIE_EP_FUNC_MSI_CAP_OFFSET     0x90
>> +
>> +/*
>> + * Root Port Registers (PCI configuration space for the root port function)
>> + */
>> +#define CDNS_PCIE_RP_BASE    0x00200000
>> +
>> +
>> +/*
>> + * Address Translation Registers
>> + */
>> +#define CDNS_PCIE_AT_BASE    0x00400000
>> +
>> +/* Region r Outbound AXI to PCIe Address Translation Register 0 */
>> +#define CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r) \
>> +     (CDNS_PCIE_AT_BASE + 0x0000 + ((r) & 0x1f) * 0x0020)
>> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS_MASK GENMASK(5, 0)
>> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(nbits) \
>> +     (((nbits) - 1) & CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS_MASK)
>> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN_MASK GENMASK(19, 12)
>> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN(devfn) \
>> +     (((devfn) << 12) & CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN_MASK)
>> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS_MASK   GENMASK(27, 20)
>> +#define  CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS(bus) \
>> +     (((bus) << 20) & CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS_MASK)
>> +
>> +/* Region r Outbound AXI to PCIe Address Translation Register 1 */
>> +#define CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r) \
>> +     (CDNS_PCIE_AT_BASE + 0x0004 + ((r) & 0x1f) * 0x0020)
>> +
>> +/* Region r Outbound PCIe Descriptor Register 0 */
>> +#define CDNS_PCIE_AT_OB_REGION_DESC0(r) \
>> +     (CDNS_PCIE_AT_BASE + 0x0008 + ((r) & 0x1f) * 0x0020)
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_MASK              GENMASK(3, 0)
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_MEM               0x2
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_IO                0x6
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE0        0xa
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE1        0xb
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_NORMAL_MSG        0xc
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_VENDOR_MSG        0xd
>> +/* Bit 23 MUST be set in RC mode. */
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID  BIT(23)
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN_MASK     GENMASK(31, 24)
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(devfn) \
>> +     (((devfn) << 24) & CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN_MASK)
>> +
>> +/* Region r Outbound PCIe Descriptor Register 1 */
>> +#define CDNS_PCIE_AT_OB_REGION_DESC1(r)      \
>> +     (CDNS_PCIE_AT_BASE + 0x000c + ((r) & 0x1f) * 0x0020)
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC1_BUS_MASK       GENMASK(7, 0)
>> +#define  CDNS_PCIE_AT_OB_REGION_DESC1_BUS(bus) \
>> +     ((bus) & CDNS_PCIE_AT_OB_REGION_DESC1_BUS_MASK)
>> +
>> +/* Region r AXI Region Base Address Register 0 */
>> +#define CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r) \
>> +     (CDNS_PCIE_AT_BASE + 0x0018 + ((r) & 0x1f) * 0x0020)
>> +#define  CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS_MASK GENMASK(5, 0)
>> +#define  CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(nbits) \
>> +     (((nbits) - 1) & CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS_MASK)
>> +
>> +/* Region r AXI Region Base Address Register 1 */
>> +#define CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r) \
>> +     (CDNS_PCIE_AT_BASE + 0x001c + ((r) & 0x1f) * 0x0020)
>> +
>> +/* Root Port BAR Inbound PCIe to AXI Address Translation Register */
>> +#define CDNS_PCIE_AT_IB_RP_BAR_ADDR0(bar) \
>> +     (CDNS_PCIE_AT_BASE + 0x0800 + (bar) * 0x0008)
>> +#define  CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS_MASK     GENMASK(5, 0)
>> +#define  CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS(nbits) \
>> +     (((nbits) - 1) & CDNS_PCIE_AT_IB_RP_BAR_ADDR0_NBITS_MASK)
>> +#define CDNS_PCIE_AT_IB_RP_BAR_ADDR1(bar) \
>> +     (CDNS_PCIE_AT_BASE + 0x0804 + (bar) * 0x0008)
>> +
>> +enum cdns_pcie_rp_bar {
>> +     RP_BAR0,
>> +     RP_BAR1,
>> +     RP_NO_BAR
>> +};
>> +
>> +/* Endpoint Function BAR Inbound PCIe to AXI Address Translation Register */
>> +#define CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR0(fn, bar) \
>> +     (CDNS_PCIE_AT_BASE + 0x0840 + (fn) * 0x0040 + (bar) * 0x0008)
>> +#define CDNS_PCIE_AT_IB_EP_FUNC_BAR_ADDR1(fn, bar) \
>> +     (CDNS_PCIE_AT_BASE + 0x0844 + (fn) * 0x0040 + (bar) * 0x0008)
>> +
>> +/* Normal/Vendor specific message access: offset inside some outbound region */
>> +#define CDNS_PCIE_NORMAL_MSG_ROUTING_MASK    GENMASK(7, 5)
>> +#define CDNS_PCIE_NORMAL_MSG_ROUTING(route) \
>> +     (((route) << 5) & CDNS_PCIE_NORMAL_MSG_ROUTING_MASK)
>> +#define CDNS_PCIE_NORMAL_MSG_CODE_MASK               GENMASK(15, 8)
>> +#define CDNS_PCIE_NORMAL_MSG_CODE(code) \
>> +     (((code) << 8) & CDNS_PCIE_NORMAL_MSG_CODE_MASK)
>> +#define CDNS_PCIE_MSG_NO_DATA                        BIT(16)
>> +
>> +enum cdns_pcie_msg_code {
>> +     MSG_CODE_ASSERT_INTA    = 0x20,
>> +     MSG_CODE_ASSERT_INTB    = 0x21,
>> +     MSG_CODE_ASSERT_INTC    = 0x22,
>> +     MSG_CODE_ASSERT_INTD    = 0x23,
>> +     MSG_CODE_DEASSERT_INTA  = 0x24,
>> +     MSG_CODE_DEASSERT_INTB  = 0x25,
>> +     MSG_CODE_DEASSERT_INTC  = 0x26,
>> +     MSG_CODE_DEASSERT_INTD  = 0x27,
>> +};
>> +
>> +enum cdns_pcie_msg_routing {
>> +     /* Route to Root Complex */
>> +     MSG_ROUTING_TO_RC,
>> +
>> +     /* Use Address Routing */
>> +     MSG_ROUTING_BY_ADDR,
>> +
>> +     /* Use ID Routing */
>> +     MSG_ROUTING_BY_ID,
>> +
>> +     /* Route as Broadcast Message from Root Complex */
>> +     MSG_ROUTING_BCAST,
>> +
>> +     /* Local message; terminate at receiver (INTx messages) */
>> +     MSG_ROUTING_LOCAL,
>> +
>> +     /* Gather & route to Root Complex (PME_TO_Ack message) */
>> +     MSG_ROUTING_GATHER,
>> +};
>> +
>> +/**
>> + * struct cdns_pcie - private data for Cadence PCIe controller drivers
>> + * @reg_base: IO mapped register base
>> + * @mem_res: start/end offsets in the physical system memory to map PCI accesses
>> + * @is_rc: tell whether the PCIe controller mode is Root Complex or Endpoint.
>> + * @bus: In Root Complex mode, the bus number
>> + */
>> +struct cdns_pcie {
>> +     void __iomem            *reg_base;
>> +     struct resource         *mem_res;
>> +     bool                    is_rc;
>> +     u8                      bus;
>> +};
>> +
>> +/* Register access */
>> +static inline void cdns_pcie_writeb(struct cdns_pcie *pcie, u32 reg, u8 value)
>> +{
>> +     writeb(value, pcie->reg_base + reg);
>> +}
>> +
>> +static inline void cdns_pcie_writew(struct cdns_pcie *pcie, u32 reg, u16 value)
>> +{
>> +     writew(value, pcie->reg_base + reg);
>> +}
>> +
>> +static inline void cdns_pcie_writel(struct cdns_pcie *pcie, u32 reg, u32 value)
>> +{
>> +     writel(value, pcie->reg_base + reg);
>> +}
>> +
>> +static inline u32 cdns_pcie_readl(struct cdns_pcie *pcie, u32 reg)
>> +{
>> +     return readl(pcie->reg_base + reg);
>> +}
>> +
>> +/* Root Port register access */
>> +static inline void cdns_pcie_rp_writeb(struct cdns_pcie *pcie,
>> +                                    u32 reg, u8 value)
>> +{
>> +     writeb(value, pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
>> +}
>> +
>> +static inline void cdns_pcie_rp_writew(struct cdns_pcie *pcie,
>> +                                    u32 reg, u16 value)
>> +{
>> +     writew(value, pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
>> +}
>> +
>> +/* Endpoint Function register access */
>> +static inline void cdns_pcie_ep_fn_writeb(struct cdns_pcie *pcie, u8 fn,
>> +                                       u32 reg, u8 value)
>> +{
>> +     writeb(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
>> +}
>> +
>> +static inline void cdns_pcie_ep_fn_writew(struct cdns_pcie *pcie, u8 fn,
>> +                                       u32 reg, u16 value)
>> +{
>> +     writew(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
>> +}
>> +
>> +static inline void cdns_pcie_ep_fn_writel(struct cdns_pcie *pcie, u8 fn,
>> +                                       u32 reg, u16 value)
>> +{
>> +     writel(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
>> +}
>> +
>> +static inline u8 cdns_pcie_ep_fn_readb(struct cdns_pcie *pcie, u8 fn, u32 reg)
>> +{
>> +     return readb(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
>> +}
>> +
>> +static inline u16 cdns_pcie_ep_fn_readw(struct cdns_pcie *pcie, u8 fn, u32 reg)
>> +{
>> +     return readw(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
>> +}
>> +
>> +static inline u32 cdns_pcie_ep_fn_readl(struct cdns_pcie *pcie, u8 fn, u32 reg)
>> +{
>> +     return readl(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
>> +}
> 
> Same comments for all endpoint related functions and defines above.
> 
> Thanks,
> Lorenzo
> 
>> +void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u32 r, bool is_io,
>> +                                u64 cpu_addr, u64 pci_addr, size_t size);
>> +
>> +void cdns_pcie_set_outbound_region_for_normal_msg(struct cdns_pcie *pcie, u32 r,
>> +                                               u64 cpu_addr);
>> +
>> +void cdns_pcie_reset_outbound_region(struct cdns_pcie *pcie, u32 r);
>> +
>> +#endif /* _PCIE_CADENCE_H */
>> --
>> 2.11.0
>>
> IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
>

[+Ard]

Hi Cyrille,

On Sun, Dec 03, 2017 at 09:44:46PM +0100, Cyrille Pitchen wrote:

[...]

> >> +cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn, int where)
> >> +{
> >> +     struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
> >> +     struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
> >> +     struct cdns_pcie *pcie = &rc->pcie;
> >> +     unsigned int busn = bus->number;
> >> +     u32 addr0, desc0;
> >> +
> >> +     if (busn < rc->bus_range->start || busn > rc->bus_range->end)
> >> +             return NULL;
> > 
> > It does not hurt but I wonder whether you really need this check.
> >
> 
> I can remove it.
>  
> >> +     if (busn == rc->bus_range->start) {
> >> +             if (devfn)
> > 
> > I suspect I know why you need this check but I ask you to explain it
> > anyway if you do not mind please.
> >
> 
> If I have understood correctly, Cadence team told me that only the root
> port is available on the first bus through device 0, function 0.
> No other device/function should connected on this bus, all other devices
> are behind at least one PCI bridge.
> 
> I can add a comment here to explain that.

That's understood, the question is what happens if you do scan devfn != 0.

> >> +                     return NULL;
> >> +
> >> +             return pcie->reg_base + (where & 0xfff);
> >> +     }
> >> +
> >> +     /* Update Output registers for AXI region 0. */
> >> +     addr0 = CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(12) |
> > 
> > Ok, so for every config access you reprogram addr0 to reflect the
> > correct bus|devfn ID in the PCI bus TLP corresponding to an ECAM address
> > in CPU physical address space, is my understanding correct ?
> >
> 
> The idea is to able to use only a 4KB memory area at a fixed address in the
> space allocated for the PCIe controller in the AXI bus. I guess the plan is
> to leave more space on the AXI bus to map all other PCIe devices.
> 
> This is just my guess. Anyway one purpose of this driver was actually to
> perform all PCI configuration space accesses through this single 4KB memory
> area in the AXI bus, changing the mapping dynamically to reach the relevant
> PCI device. 

Thank you for explaining - that matches my understanding.

> >> +             CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN(devfn) |
> >> +             CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS(busn);
> >> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(0), addr0);
> >> +
> >> +     /* Configuration Type 0 or Type 1 access. */
> >> +     desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
> >> +             CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
> >> +     /*
> >> +      * The bus number was already set once for all in desc1 by
> >> +      * cdns_pcie_host_init_address_translation().
> >> +      */
> >> +     if (busn == rc->bus_range->start + 1)
> >> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE0;
> >> +     else
> >> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE1;
> > 
> > I would like to ask you why you have to do it here and the root port
> > does not figure it out by itself, I do not have the datasheet so I am
> > just asking for my own information.
> 
> PCI configuration space registers of the root port can only be read through
> the APB bus at offset 0:
> ->reg_base + (where & 0xfff)
> 
> They are internal registers of the PCIe controller so no TLP on the PCIe bus.
> 
> However to access the PCI configuration space registers of any other device,
> the PCIe controller builds then sends a TLP on the PCIe bus using the offset
> in the 4KB AXI area as the offset of the register in the PCI configuration
> space:
> ->cfg_base + (where & 0xfff)
> 
> > 
> >> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(0), desc0);
> >> +
> >> +     return rc->cfg_base + (where & 0xfff);
> >> +}
> >> +
> >> +static struct pci_ops cdns_pcie_host_ops = {
> >> +     .map_bus        = cdns_pci_map_bus,
> >> +     .read           = pci_generic_config_read,
> >> +     .write          = pci_generic_config_write,
> >> +};
> >> +
> >> +static const struct cdns_pcie_rc_data cdns_pcie_rc_data = {
> >> +     .max_regions    = 32,
> >> +     .vendor_id      = PCI_VENDOR_ID_CDNS,
> >> +     .device_id      = 0x0200,
> >> +     .no_bar_nbits   = 32,
> >> +};
> > 
> > Should (some of) these parameters be retrieved through a DT binding ?
> >
> 
> Indeed, maybe we get max_regions and no_bar_nbits from the DT.
> 
> About the vendor and device IDs, I don't know which would be the best
> choice between some dedicated DT properties or associating a custom
> structure as above to the 'compatible' string.
> 
> Honestly, I don't have any strong preference, please just tell me what
> you would prefer :)

I think it is best to ask DT maintainers (in CC) POV on this, they
certainly have a more comprehensive view than mine on the subject - I
have just noticed that _some_ data can be retrieved through DT therefore
I raised the point - either through different compatible strings or
some IP specific properties.

> >> +static const struct of_device_id cdns_pcie_host_of_match[] = {
> >> +     { .compatible = "cdns,cdns-pcie-host",
> >> +       .data = &cdns_pcie_rc_data },
> >> +
> >> +     { },
> >> +};
> >> +
> >> +static int cdns_pcie_parse_request_of_pci_ranges(struct device *dev,
> >> +                                              struct list_head *resources,
> >> +                                              struct resource **bus_range)
> >> +{
> >> +     int err, res_valid = 0;
> >> +     struct device_node *np = dev->of_node;
> >> +     resource_size_t iobase;
> >> +     struct resource_entry *win, *tmp;
> >> +
> >> +     err = of_pci_get_host_bridge_resources(np, 0, 0xff, resources, &iobase);
> >> +     if (err)
> >> +             return err;
> >> +
> >> +     err = devm_request_pci_bus_resources(dev, resources);
> >> +     if (err)
> >> +             return err;
> >> +
> >> +     resource_list_for_each_entry_safe(win, tmp, resources) {
> >> +             struct resource *res = win->res;
> >> +
> >> +             switch (resource_type(res)) {
> >> +             case IORESOURCE_IO:
> >> +                     err = pci_remap_iospace(res, iobase);
> >> +                     if (err) {
> >> +                             dev_warn(dev, "error %d: failed to map resource %pR\n",
> >> +                                      err, res);
> >> +                             resource_list_destroy_entry(win);
> >> +                     }
> >> +                     break;
> >> +             case IORESOURCE_MEM:
> >> +                     res_valid |= !(res->flags & IORESOURCE_PREFETCH);
> >> +                     break;
> >> +             case IORESOURCE_BUS:
> >> +                     *bus_range = res;
> >> +                     break;
> >> +             }
> >> +     }
> >> +
> >> +     if (res_valid)
> >> +             return 0;
> >> +
> >> +     dev_err(dev, "non-prefetchable memory resource required\n");
> >> +     return -EINVAL;
> > 
> > Nit, I prefer you swap these two as it is done in pci-aardvark.c:
> > 
> >         if (!res_valid) {
> >                 dev_err(dev, "non-prefetchable memory resource required\n");
> >                 return -EINVAL;
> >         }
> > 
> >         return 0;
> > 
> > but as per previous replies this function can be factorized in
> > core PCI code - I would not bother unless you are willing to write
> > the patch series that does the refactoring yourself :)
> > 
> >> +}
> >> +
> >> +static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
> >> +{
> >> +     const struct cdns_pcie_rc_data *data = rc->data;
> >> +     struct cdns_pcie *pcie = &rc->pcie;
> >> +     u8 pbn, sbn, subn;
> >> +     u32 value, ctrl;
> >> +
> >> +     /*
> >> +      * Set the root complex BAR configuration register:
> >> +      * - disable both BAR0 and BAR1.
> >> +      * - enable Prefetchable Memory Base and Limit registers in type 1
> >> +      *   config space (64 bits).
> >> +      * - enable IO Base and Limit registers in type 1 config
> >> +      *   space (32 bits).
> >> +      */
> >> +     ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
> >> +     value = CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(ctrl) |
> >> +             CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(ctrl) |
> >> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE |
> >> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS |
> >> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE |
> >> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS;
> >> +     cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
> >> +
> >> +     /* Set root port configuration space */
> >> +     if (data->vendor_id != 0xffff)
> >> +             cdns_pcie_rp_writew(pcie, PCI_VENDOR_ID, data->vendor_id);
> >> +     if (data->device_id != 0xffff)
> >> +             cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, data->device_id);
> >> +
> >> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
> >> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
> >> +     cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
> >> +
> >> +     pbn = rc->bus_range->start;
> >> +     sbn = pbn + 1; /* Single root port. */
> >> +     subn = rc->bus_range->end;
> >> +     cdns_pcie_rp_writeb(pcie, PCI_PRIMARY_BUS, pbn);
> >> +     cdns_pcie_rp_writeb(pcie, PCI_SECONDARY_BUS, sbn);
> >> +     cdns_pcie_rp_writeb(pcie, PCI_SUBORDINATE_BUS, subn);
> > 
> > Again - I do not have the datasheet for this device therefore I would
> > kindly ask you how this works; it seems to me that what you are doing
> > here is done through normal configuration cycles in an ECAM compliant
> > system to program the RP PRIMARY/SECONDARY/SUBORDINATE bus - I would
> > like to understand why this code is needed.
> >
> 
> I will test without those lines to test whether I can remove them.
> 
> At first, the PCIe controller was tested by Cadence team: there was code
> in their bootloader to initialize the hardware (building the AXI <-> PCIe
> mappings, ...): the bootloader used to set the primary, secondary and
> subordinate bus numbers in the root port PCI config space.
> 
> Also there was a hardware trick to redirect accesses of the lowest
> addresses in the AXI bus to the APB bus so the PCI configuration space of
> the root port could have been accessed from the AXI bus too.
> 
> The AXI <-> PCIe mapping being done by the bootloader and the root port
> config space being accessible from the AXI bus, it was possible to use
> the pci-host-generic driver.

That's what I was getting at. Ard (CC'ed) implemented a firmware set-up
(even though it was for a different IP but maybe it applies here) that
allows the kernel to use the pci-host-generic driver to initialize the
PCI controller:

https://marc.info/?l=linux-pci&m=150360022626351&w=2

I want to understand if there is an IP initialization sequence whereby
this IP can be made to work in an ECAM compliant way and therefore
reuse (most of) the pci-host-generic driver code.

> However, the hardware trick won't be included in the final design since
> Cadence now wants to perform all PCI configuration space accesses through
> a small 4KB window at a fixed address on the AXI bus.

I would like to understand what the HW "trick" (if you can disclose it)
was, because if there is a chance to reuse the pci-host-generic driver
for this IP I want to take it (yes it may entail some firmware set-up in
the bootloader) - was it a HW trick or a specific IP SW configuration ?

> Also, we now want all initialisations to be done by the linux driver
> instead of the bootloader.

That's a choice, I do not necessarily agree with it and I think we
should aim for more standardization on the PCI host bridge set-up
at firmware->kernel handover on DT platforms.

> I simply moved all those initialisations from the bootloader to the linux
> driver but actually there is a chance that I can remove the 3 writes to
> the PCI_*_BUS registers.

I asked because I do not have this IP documentation so I rely on you to
provide the correct initialization sequence and an explanation for it,
I think I understand now the initialization sequence a bit more but it
would be good to get to the bottom of it.

Thank you,
Lorenzo

On 4 December 2017 at 18:20, Lorenzo Pieralisi
<lorenzo.pieralisi@arm.com> wrote:
> [+Ard]
>
> Hi Cyrille,
>
> On Sun, Dec 03, 2017 at 09:44:46PM +0100, Cyrille Pitchen wrote:
>
> [...]
>
>> >> +cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn, int where)
>> >> +{
>> >> +     struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
>> >> +     struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
>> >> +     struct cdns_pcie *pcie = &rc->pcie;
>> >> +     unsigned int busn = bus->number;
>> >> +     u32 addr0, desc0;
>> >> +
>> >> +     if (busn < rc->bus_range->start || busn > rc->bus_range->end)
>> >> +             return NULL;
>> >
>> > It does not hurt but I wonder whether you really need this check.
>> >
>>
>> I can remove it.
>>
>> >> +     if (busn == rc->bus_range->start) {
>> >> +             if (devfn)
>> >
>> > I suspect I know why you need this check but I ask you to explain it
>> > anyway if you do not mind please.
>> >
>>
>> If I have understood correctly, Cadence team told me that only the root
>> port is available on the first bus through device 0, function 0.
>> No other device/function should connected on this bus, all other devices
>> are behind at least one PCI bridge.
>>
>> I can add a comment here to explain that.
>
> That's understood, the question is what happens if you do scan devfn != 0.
>

OK, this is similar to the Synopsys IP. Type 0 config TLPs are not
filtered by the hardware, and so if you don't filter them in software,
the device downstream of the rootport will appear 32 times.

>> >> +                     return NULL;
>> >> +
>> >> +             return pcie->reg_base + (where & 0xfff);
>> >> +     }
>> >> +
>> >> +     /* Update Output registers for AXI region 0. */
>> >> +     addr0 = CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(12) |
>> >
>> > Ok, so for every config access you reprogram addr0 to reflect the
>> > correct bus|devfn ID in the PCI bus TLP corresponding to an ECAM address
>> > in CPU physical address space, is my understanding correct ?
>> >
>>
>> The idea is to able to use only a 4KB memory area at a fixed address in the
>> space allocated for the PCIe controller in the AXI bus. I guess the plan is
>> to leave more space on the AXI bus to map all other PCIe devices.
>>
>> This is just my guess. Anyway one purpose of this driver was actually to
>> perform all PCI configuration space accesses through this single 4KB memory
>> area in the AXI bus, changing the mapping dynamically to reach the relevant
>> PCI device.
>
> Thank you for explaining - that matches my understanding.
>
>> >> +             CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_DEVFN(devfn) |
>> >> +             CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_BUS(busn);
>> >> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(0), addr0);
>> >> +
>> >> +     /* Configuration Type 0 or Type 1 access. */
>> >> +     desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
>> >> +             CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
>> >> +     /*
>> >> +      * The bus number was already set once for all in desc1 by
>> >> +      * cdns_pcie_host_init_address_translation().
>> >> +      */
>> >> +     if (busn == rc->bus_range->start + 1)
>> >> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE0;
>> >> +     else
>> >> +             desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_CONF_TYPE1;
>> >
>> > I would like to ask you why you have to do it here and the root port
>> > does not figure it out by itself, I do not have the datasheet so I am
>> > just asking for my own information.
>>
>> PCI configuration space registers of the root port can only be read through
>> the APB bus at offset 0:
>> ->reg_base + (where & 0xfff)
>>
>> They are internal registers of the PCIe controller so no TLP on the PCIe bus.
>>
>> However to access the PCI configuration space registers of any other device,
>> the PCIe controller builds then sends a TLP on the PCIe bus using the offset
>> in the 4KB AXI area as the offset of the register in the PCI configuration
>> space:
>> ->cfg_base + (where & 0xfff)
>>
>> >
>> >> +     cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(0), desc0);
>> >> +
>> >> +     return rc->cfg_base + (where & 0xfff);
>> >> +}
>> >> +
>> >> +static struct pci_ops cdns_pcie_host_ops = {
>> >> +     .map_bus        = cdns_pci_map_bus,
>> >> +     .read           = pci_generic_config_read,
>> >> +     .write          = pci_generic_config_write,
>> >> +};
>> >> +
>> >> +static const struct cdns_pcie_rc_data cdns_pcie_rc_data = {
>> >> +     .max_regions    = 32,
>> >> +     .vendor_id      = PCI_VENDOR_ID_CDNS,
>> >> +     .device_id      = 0x0200,
>> >> +     .no_bar_nbits   = 32,
>> >> +};
>> >
>> > Should (some of) these parameters be retrieved through a DT binding ?
>> >
>>
>> Indeed, maybe we get max_regions and no_bar_nbits from the DT.
>>
>> About the vendor and device IDs, I don't know which would be the best
>> choice between some dedicated DT properties or associating a custom
>> structure as above to the 'compatible' string.
>>
>> Honestly, I don't have any strong preference, please just tell me what
>> you would prefer :)
>
> I think it is best to ask DT maintainers (in CC) POV on this, they
> certainly have a more comprehensive view than mine on the subject - I
> have just noticed that _some_ data can be retrieved through DT therefore
> I raised the point - either through different compatible strings or
> some IP specific properties.
>
>> >> +static const struct of_device_id cdns_pcie_host_of_match[] = {
>> >> +     { .compatible = "cdns,cdns-pcie-host",
>> >> +       .data = &cdns_pcie_rc_data },
>> >> +
>> >> +     { },
>> >> +};
>> >> +
>> >> +static int cdns_pcie_parse_request_of_pci_ranges(struct device *dev,
>> >> +                                              struct list_head *resources,
>> >> +                                              struct resource **bus_range)
>> >> +{
>> >> +     int err, res_valid = 0;
>> >> +     struct device_node *np = dev->of_node;
>> >> +     resource_size_t iobase;
>> >> +     struct resource_entry *win, *tmp;
>> >> +
>> >> +     err = of_pci_get_host_bridge_resources(np, 0, 0xff, resources, &iobase);
>> >> +     if (err)
>> >> +             return err;
>> >> +
>> >> +     err = devm_request_pci_bus_resources(dev, resources);
>> >> +     if (err)
>> >> +             return err;
>> >> +
>> >> +     resource_list_for_each_entry_safe(win, tmp, resources) {
>> >> +             struct resource *res = win->res;
>> >> +
>> >> +             switch (resource_type(res)) {
>> >> +             case IORESOURCE_IO:
>> >> +                     err = pci_remap_iospace(res, iobase);
>> >> +                     if (err) {
>> >> +                             dev_warn(dev, "error %d: failed to map resource %pR\n",
>> >> +                                      err, res);
>> >> +                             resource_list_destroy_entry(win);
>> >> +                     }
>> >> +                     break;
>> >> +             case IORESOURCE_MEM:
>> >> +                     res_valid |= !(res->flags & IORESOURCE_PREFETCH);
>> >> +                     break;
>> >> +             case IORESOURCE_BUS:
>> >> +                     *bus_range = res;
>> >> +                     break;
>> >> +             }
>> >> +     }
>> >> +
>> >> +     if (res_valid)
>> >> +             return 0;
>> >> +
>> >> +     dev_err(dev, "non-prefetchable memory resource required\n");
>> >> +     return -EINVAL;
>> >
>> > Nit, I prefer you swap these two as it is done in pci-aardvark.c:
>> >
>> >         if (!res_valid) {
>> >                 dev_err(dev, "non-prefetchable memory resource required\n");
>> >                 return -EINVAL;
>> >         }
>> >
>> >         return 0;
>> >
>> > but as per previous replies this function can be factorized in
>> > core PCI code - I would not bother unless you are willing to write
>> > the patch series that does the refactoring yourself :)
>> >
>> >> +}
>> >> +
>> >> +static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
>> >> +{
>> >> +     const struct cdns_pcie_rc_data *data = rc->data;
>> >> +     struct cdns_pcie *pcie = &rc->pcie;
>> >> +     u8 pbn, sbn, subn;
>> >> +     u32 value, ctrl;
>> >> +
>> >> +     /*
>> >> +      * Set the root complex BAR configuration register:
>> >> +      * - disable both BAR0 and BAR1.
>> >> +      * - enable Prefetchable Memory Base and Limit registers in type 1
>> >> +      *   config space (64 bits).
>> >> +      * - enable IO Base and Limit registers in type 1 config
>> >> +      *   space (32 bits).
>> >> +      */
>> >> +     ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
>> >> +     value = CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(ctrl) |
>> >> +             CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(ctrl) |
>> >> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE |
>> >> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS |
>> >> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE |
>> >> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS;
>> >> +     cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
>> >> +
>> >> +     /* Set root port configuration space */
>> >> +     if (data->vendor_id != 0xffff)
>> >> +             cdns_pcie_rp_writew(pcie, PCI_VENDOR_ID, data->vendor_id);
>> >> +     if (data->device_id != 0xffff)
>> >> +             cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, data->device_id);
>> >> +
>> >> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
>> >> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
>> >> +     cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
>> >> +
>> >> +     pbn = rc->bus_range->start;
>> >> +     sbn = pbn + 1; /* Single root port. */
>> >> +     subn = rc->bus_range->end;
>> >> +     cdns_pcie_rp_writeb(pcie, PCI_PRIMARY_BUS, pbn);
>> >> +     cdns_pcie_rp_writeb(pcie, PCI_SECONDARY_BUS, sbn);
>> >> +     cdns_pcie_rp_writeb(pcie, PCI_SUBORDINATE_BUS, subn);
>> >
>> > Again - I do not have the datasheet for this device therefore I would
>> > kindly ask you how this works; it seems to me that what you are doing
>> > here is done through normal configuration cycles in an ECAM compliant
>> > system to program the RP PRIMARY/SECONDARY/SUBORDINATE bus - I would
>> > like to understand why this code is needed.
>> >
>>
>> I will test without those lines to test whether I can remove them.
>>
>> At first, the PCIe controller was tested by Cadence team: there was code
>> in their bootloader to initialize the hardware (building the AXI <-> PCIe
>> mappings, ...): the bootloader used to set the primary, secondary and
>> subordinate bus numbers in the root port PCI config space.
>>
>> Also there was a hardware trick to redirect accesses of the lowest
>> addresses in the AXI bus to the APB bus so the PCI configuration space of
>> the root port could have been accessed from the AXI bus too.
>>
>> The AXI <-> PCIe mapping being done by the bootloader and the root port
>> config space being accessible from the AXI bus, it was possible to use
>> the pci-host-generic driver.
>
> That's what I was getting at. Ard (CC'ed) implemented a firmware set-up
> (even though it was for a different IP but maybe it applies here) that
> allows the kernel to use the pci-host-generic driver to initialize the
> PCI controller:
>
> https://marc.info/?l=linux-pci&m=150360022626351&w=2
>
> I want to understand if there is an IP initialization sequence whereby
> this IP can be made to work in an ECAM compliant way and therefore
> reuse (most of) the pci-host-generic driver code.
>

I think the Synopsys case is probably very similar. There are some
registers that look like the config space of a root port, but in
reality, every memory access that hits a live host bridge window is
forwarded onto the link, regardless of the values of the bridge BARs.
That is why in the quoted case, we can get away with ignoring the root
port altogether, rather than jumping through hoops to make the IP
block's PCI config space registers appear at B/D/F 0/0/0, while still
having to filter type 0 config TLPs going onto the link (which is
arguably the job of the root port to begin with)

So if this IP does implement a proper root port (i.e., one where the
bridge BARs are actually taken into account, and where type 0 config
TLPs are in fact filtered), I strongly recommend mapping its config
space registers in an ECAM compliant matter, which implies no
accessors in the OS.

However, given the observation above, this IP does not appear to
filter type 0 config TLPs to devfn > 0 downstream of the root port
either.

>> However, the hardware trick won't be included in the final design since
>> Cadence now wants to perform all PCI configuration space accesses through
>> a small 4KB window at a fixed address on the AXI bus.
>
> I would like to understand what the HW "trick" (if you can disclose it)
> was, because if there is a chance to reuse the pci-host-generic driver
> for this IP I want to take it (yes it may entail some firmware set-up in
> the bootloader) - was it a HW trick or a specific IP SW configuration ?
>
>> Also, we now want all initialisations to be done by the linux driver
>> instead of the bootloader.
>
> That's a choice, I do not necessarily agree with it and I think we
> should aim for more standardization on the PCI host bridge set-up
> at firmware->kernel handover on DT platforms.
>

Well, for one, it means this IP will never be supported by ACPI, which
seems like a huge downside to me.

>> I simply moved all those initialisations from the bootloader to the linux
>> driver but actually there is a chance that I can remove the 3 writes to
>> the PCI_*_BUS registers.
>
> I asked because I do not have this IP documentation so I rely on you to
> provide the correct initialization sequence and an explanation for it,
> I think I understand now the initialization sequence a bit more but it
> would be good to get to the bottom of it.
>

On Mon, Dec 04, 2017 at 06:49:12PM +0000, Ard Biesheuvel wrote:

[...]

> >> >> +static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
> >> >> +{
> >> >> +     const struct cdns_pcie_rc_data *data = rc->data;
> >> >> +     struct cdns_pcie *pcie = &rc->pcie;
> >> >> +     u8 pbn, sbn, subn;
> >> >> +     u32 value, ctrl;
> >> >> +
> >> >> +     /*
> >> >> +      * Set the root complex BAR configuration register:
> >> >> +      * - disable both BAR0 and BAR1.
> >> >> +      * - enable Prefetchable Memory Base and Limit registers in type 1
> >> >> +      *   config space (64 bits).
> >> >> +      * - enable IO Base and Limit registers in type 1 config
> >> >> +      *   space (32 bits).
> >> >> +      */
> >> >> +     ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
> >> >> +     value = CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(ctrl) |
> >> >> +             CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(ctrl) |
> >> >> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE |
> >> >> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS |
> >> >> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE |
> >> >> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS;
> >> >> +     cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
> >> >> +
> >> >> +     /* Set root port configuration space */
> >> >> +     if (data->vendor_id != 0xffff)
> >> >> +             cdns_pcie_rp_writew(pcie, PCI_VENDOR_ID, data->vendor_id);
> >> >> +     if (data->device_id != 0xffff)
> >> >> +             cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, data->device_id);
> >> >> +
> >> >> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
> >> >> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
> >> >> +     cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
> >> >> +
> >> >> +     pbn = rc->bus_range->start;
> >> >> +     sbn = pbn + 1; /* Single root port. */
> >> >> +     subn = rc->bus_range->end;
> >> >> +     cdns_pcie_rp_writeb(pcie, PCI_PRIMARY_BUS, pbn);
> >> >> +     cdns_pcie_rp_writeb(pcie, PCI_SECONDARY_BUS, sbn);
> >> >> +     cdns_pcie_rp_writeb(pcie, PCI_SUBORDINATE_BUS, subn);
> >> >
> >> > Again - I do not have the datasheet for this device therefore I would
> >> > kindly ask you how this works; it seems to me that what you are doing
> >> > here is done through normal configuration cycles in an ECAM compliant
> >> > system to program the RP PRIMARY/SECONDARY/SUBORDINATE bus - I would
> >> > like to understand why this code is needed.
> >> >
> >>
> >> I will test without those lines to test whether I can remove them.
> >>
> >> At first, the PCIe controller was tested by Cadence team: there was code
> >> in their bootloader to initialize the hardware (building the AXI <-> PCIe
> >> mappings, ...): the bootloader used to set the primary, secondary and
> >> subordinate bus numbers in the root port PCI config space.
> >>
> >> Also there was a hardware trick to redirect accesses of the lowest
> >> addresses in the AXI bus to the APB bus so the PCI configuration space of
> >> the root port could have been accessed from the AXI bus too.
> >>
> >> The AXI <-> PCIe mapping being done by the bootloader and the root port
> >> config space being accessible from the AXI bus, it was possible to use
> >> the pci-host-generic driver.
> >
> > That's what I was getting at. Ard (CC'ed) implemented a firmware set-up
> > (even though it was for a different IP but maybe it applies here) that
> > allows the kernel to use the pci-host-generic driver to initialize the
> > PCI controller:
> >
> > https://marc.info/?l=linux-pci&m=150360022626351&w=2
> >
> > I want to understand if there is an IP initialization sequence whereby
> > this IP can be made to work in an ECAM compliant way and therefore
> > reuse (most of) the pci-host-generic driver code.
> >
> 
> I think the Synopsys case is probably very similar. There are some
> registers that look like the config space of a root port, but in
> reality, every memory access that hits a live host bridge window is
> forwarded onto the link, regardless of the values of the bridge BARs.
> That is why in the quoted case, we can get away with ignoring the root
> port altogether, rather than jumping through hoops to make the IP
> block's PCI config space registers appear at B/D/F 0/0/0, while still
> having to filter type 0 config TLPs going onto the link (which is
> arguably the job of the root port to begin with)
> 
> So if this IP does implement a proper root port (i.e., one where the
> bridge BARs are actually taken into account, and where type 0 config
> TLPs are in fact filtered), I strongly recommend mapping its config
> space registers in an ECAM compliant matter, which implies no
> accessors in the OS.
> 
> However, given the observation above, this IP does not appear to
> filter type 0 config TLPs to devfn > 0 downstream of the root port
> either.

Unfortunately that matches my understanding too, let's wait for
Cyrille's reply on my query.

> >> However, the hardware trick won't be included in the final design since
> >> Cadence now wants to perform all PCI configuration space accesses through
> >> a small 4KB window at a fixed address on the AXI bus.
> >
> > I would like to understand what the HW "trick" (if you can disclose it)
> > was, because if there is a chance to reuse the pci-host-generic driver
> > for this IP I want to take it (yes it may entail some firmware set-up in
> > the bootloader) - was it a HW trick or a specific IP SW configuration ?
> >
> >> Also, we now want all initialisations to be done by the linux driver
> >> instead of the bootloader.
> >
> > That's a choice, I do not necessarily agree with it and I think we
> > should aim for more standardization on the PCI host bridge set-up
> > at firmware->kernel handover on DT platforms.
> >
> 
> Well, for one, it means this IP will never be supported by ACPI, which
> seems like a huge downside to me.

Yes it is - that's exactly where my comments were heading.

Thanks,
Lorenzo

Hi all,

Le 06/12/2017 à 12:32, Lorenzo Pieralisi a écrit :
> On Mon, Dec 04, 2017 at 06:49:12PM +0000, Ard Biesheuvel wrote:
> 
> [...]
> 
>>>>>> +static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
>>>>>> +{
>>>>>> +     const struct cdns_pcie_rc_data *data = rc->data;
>>>>>> +     struct cdns_pcie *pcie = &rc->pcie;
>>>>>> +     u8 pbn, sbn, subn;
>>>>>> +     u32 value, ctrl;
>>>>>> +
>>>>>> +     /*
>>>>>> +      * Set the root complex BAR configuration register:
>>>>>> +      * - disable both BAR0 and BAR1.
>>>>>> +      * - enable Prefetchable Memory Base and Limit registers in type 1
>>>>>> +      *   config space (64 bits).
>>>>>> +      * - enable IO Base and Limit registers in type 1 config
>>>>>> +      *   space (32 bits).
>>>>>> +      */
>>>>>> +     ctrl = CDNS_PCIE_LM_BAR_CFG_CTRL_DISABLED;
>>>>>> +     value = CDNS_PCIE_LM_RC_BAR_CFG_BAR0_CTRL(ctrl) |
>>>>>> +             CDNS_PCIE_LM_RC_BAR_CFG_BAR1_CTRL(ctrl) |
>>>>>> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_ENABLE |
>>>>>> +             CDNS_PCIE_LM_RC_BAR_CFG_PREFETCH_MEM_64BITS |
>>>>>> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_ENABLE |
>>>>>> +             CDNS_PCIE_LM_RC_BAR_CFG_IO_32BITS;
>>>>>> +     cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
>>>>>> +
>>>>>> +     /* Set root port configuration space */
>>>>>> +     if (data->vendor_id != 0xffff)
>>>>>> +             cdns_pcie_rp_writew(pcie, PCI_VENDOR_ID, data->vendor_id);
>>>>>> +     if (data->device_id != 0xffff)
>>>>>> +             cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, data->device_id);
>>>>>> +
>>>>>> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
>>>>>> +     cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
>>>>>> +     cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
>>>>>> +
>>>>>> +     pbn = rc->bus_range->start;
>>>>>> +     sbn = pbn + 1; /* Single root port. */
>>>>>> +     subn = rc->bus_range->end;
>>>>>> +     cdns_pcie_rp_writeb(pcie, PCI_PRIMARY_BUS, pbn);
>>>>>> +     cdns_pcie_rp_writeb(pcie, PCI_SECONDARY_BUS, sbn);
>>>>>> +     cdns_pcie_rp_writeb(pcie, PCI_SUBORDINATE_BUS, subn);
>>>>>
>>>>> Again - I do not have the datasheet for this device therefore I would
>>>>> kindly ask you how this works; it seems to me that what you are doing
>>>>> here is done through normal configuration cycles in an ECAM compliant
>>>>> system to program the RP PRIMARY/SECONDARY/SUBORDINATE bus - I would
>>>>> like to understand why this code is needed.
>>>>>
>>>>
>>>> I will test without those lines to test whether I can remove them.
>>>>
>>>> At first, the PCIe controller was tested by Cadence team: there was code
>>>> in their bootloader to initialize the hardware (building the AXI <-> PCIe
>>>> mappings, ...): the bootloader used to set the primary, secondary and
>>>> subordinate bus numbers in the root port PCI config space.
>>>>
>>>> Also there was a hardware trick to redirect accesses of the lowest
>>>> addresses in the AXI bus to the APB bus so the PCI configuration space of
>>>> the root port could have been accessed from the AXI bus too.
>>>>
>>>> The AXI <-> PCIe mapping being done by the bootloader and the root port
>>>> config space being accessible from the AXI bus, it was possible to use
>>>> the pci-host-generic driver.
>>>
>>> That's what I was getting at. Ard (CC'ed) implemented a firmware set-up
>>> (even though it was for a different IP but maybe it applies here) that
>>> allows the kernel to use the pci-host-generic driver to initialize the
>>> PCI controller:
>>>
>>> https://marc.info/?l=linux-pci&m=150360022626351&w=2
>>>
>>> I want to understand if there is an IP initialization sequence whereby
>>> this IP can be made to work in an ECAM compliant way and therefore
>>> reuse (most of) the pci-host-generic driver code.
>>>
>>
>> I think the Synopsys case is probably very similar. There are some
>> registers that look like the config space of a root port, but in
>> reality, every memory access that hits a live host bridge window is
>> forwarded onto the link, regardless of the values of the bridge BARs.
>> That is why in the quoted case, we can get away with ignoring the root
>> port altogether, rather than jumping through hoops to make the IP
>> block's PCI config space registers appear at B/D/F 0/0/0, while still
>> having to filter type 0 config TLPs going onto the link (which is
>> arguably the job of the root port to begin with)
>>
>> So if this IP does implement a proper root port (i.e., one where the
>> bridge BARs are actually taken into account, and where type 0 config
>> TLPs are in fact filtered), I strongly recommend mapping its config
>> space registers in an ECAM compliant matter, which implies no
>> accessors in the OS.
>>
>> However, given the observation above, this IP does not appear to
>> filter type 0 config TLPs to devfn > 0 downstream of the root port
>> either.
> 
> Unfortunately that matches my understanding too, let's wait for
> Cyrille's reply on my query.
> 
>>>> However, the hardware trick won't be included in the final design since
>>>> Cadence now wants to perform all PCI configuration space accesses through
>>>> a small 4KB window at a fixed address on the AXI bus.
>>>
>>> I would like to understand what the HW "trick" (if you can disclose it)
>>> was, because if there is a chance to reuse the pci-host-generic driver
>>> for this IP I want to take it (yes it may entail some firmware set-up in
>>> the bootloader) - was it a HW trick or a specific IP SW configuration ?
>>>

I will have to ask for details to Cadence designers if needed but when I
asked them about it, they explained me that AXI bus accesses in a small
window (I guess 4KB width) were redirected to the APB bus where lay the
registers for the root port PCI configuration space.

I was some hardware trick which won't be included in the final design, so
we can't enable or disable it by software.

Actually, this is requirement from the Cadence's customer that the host
driver can access the PCI config space of any device in sub ordinates
buses through a small memory area on the AXI bus. For some reason, they
don't want an ECAM compliant controller.

I don't know the reason but my guess is that they don't want to waste to
much space allocated to the PCIe controller on the AXI bus, likely on a
32-bit platform. As I said, this is such an assumption.

>>>> Also, we now want all initialisations to be done by the linux driver
>>>> instead of the bootloader.
>>>
>>> That's a choice, I do not necessarily agree with it and I think we
>>> should aim for more standardization on the PCI host bridge set-up
>>> at firmware->kernel handover on DT platforms.
>>>

It was another requirement of Cadence's customer that the PCIe host
controller initialization is done by the Linux driver rather than by
some boot loader.

Best regards,

Cyrille

>>
>> Well, for one, it means this IP will never be supported by ACPI, which
>> seems like a huge downside to me.
> 
> Yes it is - that's exactly where my comments were heading.
> 
> Thanks,
> Lorenzo
>