[v3,2/6] PCI: iproc: Add INTx support with better modeling
diff mbox series

Message ID 1575349026-8743-3-git-send-email-srinath.mannam@broadcom.com
State New
Delegated to: Lorenzo Pieralisi
Headers show
Series
  • PAXB INTx support with proper model
Related show

Commit Message

Srinath Mannam Dec. 3, 2019, 4:57 a.m. UTC
From: Ray Jui <ray.jui@broadcom.com>

Add PCIe legacy interrupt INTx support to the iProc PCIe driver by
modeling it with its own IRQ domain. All 4 interrupts INTA, INTB, INTC,
INTD share the same interrupt line connected to the GIC in the system,
while the status of each INTx can be obtained through the INTX CSR
register

Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Srinath Mannam <srinath.mannam@broadcom.com>
---
 drivers/pci/controller/pcie-iproc.c | 100 +++++++++++++++++++++++++++++++++++-
 drivers/pci/controller/pcie-iproc.h |   6 +++
 2 files changed, 104 insertions(+), 2 deletions(-)

Comments

Andrew Murray Dec. 3, 2019, 3:55 p.m. UTC | #1
On Tue, Dec 03, 2019 at 10:27:02AM +0530, Srinath Mannam wrote:
> From: Ray Jui <ray.jui@broadcom.com>
> 
> Add PCIe legacy interrupt INTx support to the iProc PCIe driver by
> modeling it with its own IRQ domain. All 4 interrupts INTA, INTB, INTC,
> INTD share the same interrupt line connected to the GIC in the system,
> while the status of each INTx can be obtained through the INTX CSR
> register
> 
> Signed-off-by: Ray Jui <ray.jui@broadcom.com>
> Signed-off-by: Srinath Mannam <srinath.mannam@broadcom.com>
> ---
>  drivers/pci/controller/pcie-iproc.c | 100 +++++++++++++++++++++++++++++++++++-
>  drivers/pci/controller/pcie-iproc.h |   6 +++
>  2 files changed, 104 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c
> index 2d457bf..e90c22e 100644
> --- a/drivers/pci/controller/pcie-iproc.c
> +++ b/drivers/pci/controller/pcie-iproc.c
> @@ -14,6 +14,7 @@
>  #include <linux/delay.h>
>  #include <linux/interrupt.h>
>  #include <linux/irqchip/arm-gic-v3.h>
> +#include <linux/irqchip/chained_irq.h>
>  #include <linux/platform_device.h>
>  #include <linux/of_address.h>
>  #include <linux/of_pci.h>
> @@ -270,6 +271,7 @@ enum iproc_pcie_reg {
>  
>  	/* enable INTx */
>  	IPROC_PCIE_INTX_EN,
> +	IPROC_PCIE_INTX_CSR,
>  
>  	/* outbound address mapping */
>  	IPROC_PCIE_OARR0,
> @@ -314,6 +316,7 @@ static const u16 iproc_pcie_reg_paxb_bcma[] = {
>  	[IPROC_PCIE_CFG_ADDR]		= 0x1f8,
>  	[IPROC_PCIE_CFG_DATA]		= 0x1fc,
>  	[IPROC_PCIE_INTX_EN]		= 0x330,
> +	[IPROC_PCIE_INTX_CSR]		= 0x334,
>  	[IPROC_PCIE_LINK_STATUS]	= 0xf0c,
>  };
>  
> @@ -325,6 +328,7 @@ static const u16 iproc_pcie_reg_paxb[] = {
>  	[IPROC_PCIE_CFG_ADDR]		= 0x1f8,
>  	[IPROC_PCIE_CFG_DATA]		= 0x1fc,
>  	[IPROC_PCIE_INTX_EN]		= 0x330,
> +	[IPROC_PCIE_INTX_CSR]		= 0x334,
>  	[IPROC_PCIE_OARR0]		= 0xd20,
>  	[IPROC_PCIE_OMAP0]		= 0xd40,
>  	[IPROC_PCIE_OARR1]		= 0xd28,
> @@ -341,6 +345,7 @@ static const u16 iproc_pcie_reg_paxb_v2[] = {
>  	[IPROC_PCIE_CFG_ADDR]		= 0x1f8,
>  	[IPROC_PCIE_CFG_DATA]		= 0x1fc,
>  	[IPROC_PCIE_INTX_EN]		= 0x330,
> +	[IPROC_PCIE_INTX_CSR]		= 0x334,
>  	[IPROC_PCIE_OARR0]		= 0xd20,
>  	[IPROC_PCIE_OMAP0]		= 0xd40,
>  	[IPROC_PCIE_OARR1]		= 0xd28,
> @@ -846,9 +851,95 @@ static int iproc_pcie_check_link(struct iproc_pcie *pcie)
>  	return link_is_active ? 0 : -ENODEV;
>  }
>  
> -static void iproc_pcie_enable(struct iproc_pcie *pcie)
> +static int iproc_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> +			       irq_hw_number_t hwirq)
>  {
> +	irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
> +	irq_set_chip_data(irq, domain->host_data);
> +
> +	return 0;
> +}
> +
> +static const struct irq_domain_ops intx_domain_ops = {
> +	.map = iproc_pcie_intx_map,
> +};
> +
> +static void iproc_pcie_isr(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	struct iproc_pcie *pcie;
> +	struct device *dev;
> +	unsigned long status;
> +	u32 bit, virq;
> +
> +	chained_irq_enter(chip, desc);
> +	pcie = irq_desc_get_handler_data(desc);
> +	dev = pcie->dev;
> +
> +	/* go through INTx A, B, C, D until all interrupts are handled */
> +	do {
> +		status = iproc_pcie_read_reg(pcie, IPROC_PCIE_INTX_CSR);

By performing this read once and outside of the do/while loop you may improve
performance. I wonder how probable it is to get another INTx whilst handling
one?


> +		for_each_set_bit(bit, &status, PCI_NUM_INTX) {
> +			virq = irq_find_mapping(pcie->irq_domain, bit);
> +			if (virq)
> +				generic_handle_irq(virq);
> +			else
> +				dev_err(dev, "unexpected INTx%u\n", bit);
> +		}
> +	} while ((status & SYS_RC_INTX_MASK) != 0);
> +
> +	chained_irq_exit(chip, desc);
> +}
> +
> +static int iproc_pcie_intx_enable(struct iproc_pcie *pcie)
> +{
> +	struct device *dev = pcie->dev;
> +	struct device_node *node;
> +	int ret;
> +
>  	iproc_pcie_write_reg(pcie, IPROC_PCIE_INTX_EN, SYS_RC_INTX_MASK);
> +	/*
> +	 * BCMA devices do not map INTx the same way as platform devices. All
> +	 * BCMA needs is the above code to enable INTx
> +	 */

NIT: Move this comment above the line of code?


> +
> +	node = of_get_compatible_child(dev->of_node, "brcm,iproc-intc");

As the interrupt controller is built into the PCI controller, what is the
rationale for representing this as a separate device tree device?

Thanks,

Andrew Murray

> +	if (node)
> +		pcie->irq = of_irq_get(node, 0);
> +
> +	if (!node || pcie->irq <= 0)
> +		return 0;
> +
> +	/* set IRQ handler */
> +	irq_set_chained_handler_and_data(pcie->irq, iproc_pcie_isr, pcie);
> +
> +	/* add IRQ domain for INTx */
> +	pcie->irq_domain = irq_domain_add_linear(node, PCI_NUM_INTX,
> +						 &intx_domain_ops, pcie);
> +	if (!pcie->irq_domain) {
> +		dev_err(dev, "failed to add INTx IRQ domain\n");
> +		ret = -ENOMEM;
> +		goto err_rm_handler_data;
> +	}
> +
> +	return 0;
> +
> +err_rm_handler_data:
> +	of_node_put(node);
> +	irq_set_chained_handler_and_data(pcie->irq, NULL, NULL);
> +
> +	return ret;
> +}
> +
> +static void iproc_pcie_intx_disable(struct iproc_pcie *pcie)
> +{
> +	iproc_pcie_write_reg(pcie, IPROC_PCIE_INTX_EN, 0x0);
> +
> +	if (pcie->irq <= 0)
> +		return;
> +
> +	irq_domain_remove(pcie->irq_domain);
> +	irq_set_chained_handler_and_data(pcie->irq, NULL, NULL);
>  }
>  
>  static inline bool iproc_pcie_ob_is_valid(struct iproc_pcie *pcie,
> @@ -1537,7 +1628,11 @@ int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res)
>  		goto err_power_off_phy;
>  	}
>  
> -	iproc_pcie_enable(pcie);
> +	ret = iproc_pcie_intx_enable(pcie);
> +	if (ret) {
> +		dev_err(dev, "failed to enable INTx\n");
> +		goto err_power_off_phy;
> +	}
>  
>  	if (IS_ENABLED(CONFIG_PCI_MSI))
>  		if (iproc_pcie_msi_enable(pcie))
> @@ -1582,6 +1677,7 @@ int iproc_pcie_remove(struct iproc_pcie *pcie)
>  	pci_remove_root_bus(pcie->root_bus);
>  
>  	iproc_pcie_msi_disable(pcie);
> +	iproc_pcie_intx_disable(pcie);
>  
>  	phy_power_off(pcie->phy);
>  	phy_exit(pcie->phy);
> diff --git a/drivers/pci/controller/pcie-iproc.h b/drivers/pci/controller/pcie-iproc.h
> index 4f03ea5..103e568 100644
> --- a/drivers/pci/controller/pcie-iproc.h
> +++ b/drivers/pci/controller/pcie-iproc.h
> @@ -74,6 +74,9 @@ struct iproc_msi;
>   * @ib: inbound mapping related parameters
>   * @ib_map: outbound mapping region related parameters
>   *
> + * @irq: interrupt line wired to the generic GIC for INTx
> + * @irq_domain: IRQ domain for INTx
> + *
>   * @need_msi_steer: indicates additional configuration of the iProc PCIe
>   * controller is required to steer MSI writes to external interrupt controller
>   * @msi: MSI data
> @@ -102,6 +105,9 @@ struct iproc_pcie {
>  	struct iproc_pcie_ib ib;
>  	const struct iproc_pcie_ib_map *ib_map;
>  
> +	int irq;
> +	struct irq_domain *irq_domain;
> +
>  	bool need_msi_steer;
>  	struct iproc_msi *msi;
>  };
> -- 
> 2.7.4
>
Andy Shevchenko Dec. 3, 2019, 7:27 p.m. UTC | #2
On Tue, Dec 3, 2019 at 5:55 PM Andrew Murray <andrew.murray@arm.com> wrote:
> On Tue, Dec 03, 2019 at 10:27:02AM +0530, Srinath Mannam wrote:

> > +     /* go through INTx A, B, C, D until all interrupts are handled */
> > +     do {
> > +             status = iproc_pcie_read_reg(pcie, IPROC_PCIE_INTX_CSR);
>
> By performing this read once and outside of the do/while loop you may improve
> performance. I wonder how probable it is to get another INTx whilst handling
> one?

May I ask how it can be improved?
One read will be needed any way, and so does this code.

> > +             for_each_set_bit(bit, &status, PCI_NUM_INTX) {
> > +                     virq = irq_find_mapping(pcie->irq_domain, bit);
> > +                     if (virq)
> > +                             generic_handle_irq(virq);
> > +                     else
> > +                             dev_err(dev, "unexpected INTx%u\n", bit);
> > +             }
> > +     } while ((status & SYS_RC_INTX_MASK) != 0);
Ray Jui Dec. 3, 2019, 10:09 p.m. UTC | #3
On 12/3/19 11:27 AM, Andy Shevchenko wrote:
> On Tue, Dec 3, 2019 at 5:55 PM Andrew Murray <andrew.murray@arm.com> wrote:
>> On Tue, Dec 03, 2019 at 10:27:02AM +0530, Srinath Mannam wrote:
> 
>>> +     /* go through INTx A, B, C, D until all interrupts are handled */
>>> +     do {
>>> +             status = iproc_pcie_read_reg(pcie, IPROC_PCIE_INTX_CSR);
>>
>> By performing this read once and outside of the do/while loop you may improve
>> performance. I wonder how probable it is to get another INTx whilst handling
>> one?
> 
> May I ask how it can be improved?
> One read will be needed any way, and so does this code.
> 

I guess the current code will cause the IPROC_PCIE_INTX_CSR register to 
be read TWICE, if it's ever set to start with.

But then if we do it outside of the while loop, if we ever receive an 
interrupt while servicing one, the interrupt will still need to be 
serviced, and in this case, it will cause additional context switch 
overhead by going out and back in the interrupt context.

My take is that it's probably more ideal to leave this portion of code 
as it is.

>>> +             for_each_set_bit(bit, &status, PCI_NUM_INTX) {
>>> +                     virq = irq_find_mapping(pcie->irq_domain, bit);
>>> +                     if (virq)
>>> +                             generic_handle_irq(virq);
>>> +                     else
>>> +                             dev_err(dev, "unexpected INTx%u\n", bit);
>>> +             }
>>> +     } while ((status & SYS_RC_INTX_MASK) != 0);
>
Andy Shevchenko Dec. 4, 2019, 8:29 a.m. UTC | #4
On Wed, Dec 4, 2019 at 12:09 AM Ray Jui <ray.jui@broadcom.com> wrote:
> On 12/3/19 11:27 AM, Andy Shevchenko wrote:
> > On Tue, Dec 3, 2019 at 5:55 PM Andrew Murray <andrew.murray@arm.com> wrote:
> >> On Tue, Dec 03, 2019 at 10:27:02AM +0530, Srinath Mannam wrote:
> >
> >>> +     /* go through INTx A, B, C, D until all interrupts are handled */
> >>> +     do {
> >>> +             status = iproc_pcie_read_reg(pcie, IPROC_PCIE_INTX_CSR);
> >>
> >> By performing this read once and outside of the do/while loop you may improve
> >> performance. I wonder how probable it is to get another INTx whilst handling
> >> one?
> >
> > May I ask how it can be improved?
> > One read will be needed any way, and so does this code.
> >
>
> I guess the current code will cause the IPROC_PCIE_INTX_CSR register to
> be read TWICE, if it's ever set to start with.
>
> But then if we do it outside of the while loop, if we ever receive an
> interrupt while servicing one, the interrupt will still need to be
> serviced, and in this case, it will cause additional context switch
> overhead by going out and back in the interrupt context.
>
> My take is that it's probably more ideal to leave this portion of code
> as it is.

Can't we simple drop a do-while completely and leave only
for_each_set_bit() loop?

>
> >>> +             for_each_set_bit(bit, &status, PCI_NUM_INTX) {
> >>> +                     virq = irq_find_mapping(pcie->irq_domain, bit);
> >>> +                     if (virq)
> >>> +                             generic_handle_irq(virq);
> >>> +                     else
> >>> +                             dev_err(dev, "unexpected INTx%u\n", bit);
> >>> +             }
> >>> +     } while ((status & SYS_RC_INTX_MASK) != 0);
> >
Andrew Murray Dec. 4, 2019, 4:07 p.m. UTC | #5
On Wed, Dec 04, 2019 at 10:29:51AM +0200, Andy Shevchenko wrote:
> On Wed, Dec 4, 2019 at 12:09 AM Ray Jui <ray.jui@broadcom.com> wrote:
> > On 12/3/19 11:27 AM, Andy Shevchenko wrote:
> > > On Tue, Dec 3, 2019 at 5:55 PM Andrew Murray <andrew.murray@arm.com> wrote:
> > >> On Tue, Dec 03, 2019 at 10:27:02AM +0530, Srinath Mannam wrote:
> > >
> > >>> +     /* go through INTx A, B, C, D until all interrupts are handled */
> > >>> +     do {
> > >>> +             status = iproc_pcie_read_reg(pcie, IPROC_PCIE_INTX_CSR);
> > >>
> > >> By performing this read once and outside of the do/while loop you may improve
> > >> performance. I wonder how probable it is to get another INTx whilst handling
> > >> one?
> > >
> > > May I ask how it can be improved?
> > > One read will be needed any way, and so does this code.
> > >
> >
> > I guess the current code will cause the IPROC_PCIE_INTX_CSR register to
> > be read TWICE, if it's ever set to start with.
> >
> > But then if we do it outside of the while loop, if we ever receive an
> > interrupt while servicing one, the interrupt will still need to be
> > serviced, and in this case, it will cause additional context switch
> > overhead by going out and back in the interrupt context.

Yes it's a trade off - if you dropped the do/while loop and thus had a single
read you'd reduce the overhead on interrupt handling in every case except
where another INTx is received whilst in this function. But as you point out
each time that does happen you'll pay the penalty of a context switch.

I don't have any knowledge of this platform so I have no idea if such a change
would be good/bad or material. However I thought I'd point it out. Looking at
the other controller drivers, some handle in a loop and some don't.


> >
> > My take is that it's probably more ideal to leave this portion of code
> > as it is.
> 
> Can't we simple drop a do-while completely and leave only
> for_each_set_bit() loop?
> 

I'm happy either way.

Thanks,

Andrew Murray

> >
> > >>> +             for_each_set_bit(bit, &status, PCI_NUM_INTX) {
> > >>> +                     virq = irq_find_mapping(pcie->irq_domain, bit);
> > >>> +                     if (virq)
> > >>> +                             generic_handle_irq(virq);
> > >>> +                     else
> > >>> +                             dev_err(dev, "unexpected INTx%u\n", bit);
> > >>> +             }
> > >>> +     } while ((status & SYS_RC_INTX_MASK) != 0);
> > >
> 
> 
> 
> -- 
> With Best Regards,
> Andy Shevchenko
Ray Jui Dec. 4, 2019, 6:36 p.m. UTC | #6
On 12/4/19 8:07 AM, Andrew Murray wrote:
> On Wed, Dec 04, 2019 at 10:29:51AM +0200, Andy Shevchenko wrote:
>> On Wed, Dec 4, 2019 at 12:09 AM Ray Jui <ray.jui@broadcom.com> wrote:
>>> On 12/3/19 11:27 AM, Andy Shevchenko wrote:
>>>> On Tue, Dec 3, 2019 at 5:55 PM Andrew Murray <andrew.murray@arm.com> wrote:
>>>>> On Tue, Dec 03, 2019 at 10:27:02AM +0530, Srinath Mannam wrote:
>>>>
>>>>>> +     /* go through INTx A, B, C, D until all interrupts are handled */
>>>>>> +     do {
>>>>>> +             status = iproc_pcie_read_reg(pcie, IPROC_PCIE_INTX_CSR);
>>>>>
>>>>> By performing this read once and outside of the do/while loop you may improve
>>>>> performance. I wonder how probable it is to get another INTx whilst handling
>>>>> one?
>>>>
>>>> May I ask how it can be improved?
>>>> One read will be needed any way, and so does this code.
>>>>
>>>
>>> I guess the current code will cause the IPROC_PCIE_INTX_CSR register to
>>> be read TWICE, if it's ever set to start with.
>>>
>>> But then if we do it outside of the while loop, if we ever receive an
>>> interrupt while servicing one, the interrupt will still need to be
>>> serviced, and in this case, it will cause additional context switch
>>> overhead by going out and back in the interrupt context.
> 
> Yes it's a trade off - if you dropped the do/while loop and thus had a single
> read you'd reduce the overhead on interrupt handling in every case except
> where another INTx is received whilst in this function. But as you point out
> each time that does happen you'll pay the penalty of a context switch.
>

Exactly, it's a tradeoff between: 1) saving one register read (which is 
likely in the 10th of nanosecond range) in all INTx handling; and 2) 
saving context switches (which is likely in 10th of microsecond range) 
in cases when we have multiple INTx when servicing it.

The current implementation takes 2), which I thought it makes sense.

> I don't have any knowledge of this platform so I have no idea if such a change
> would be good/bad or material. However I thought I'd point it out. Looking at
> the other controller drivers, some handle in a loop and some don't.
> 
> 
>>>
>>> My take is that it's probably more ideal to leave this portion of code
>>> as it is.
>>
>> Can't we simple drop a do-while completely and leave only
>> for_each_set_bit() loop?
>>

Like both Andrew and I pointed out. There's a tradeoff here. Could you 
please help to justify why you favor 1) than 2)?

> 
> I'm happy either way.
> 
> Thanks,
> 
> Andrew Murray
> 
>>>
>>>>>> +             for_each_set_bit(bit, &status, PCI_NUM_INTX) {
>>>>>> +                     virq = irq_find_mapping(pcie->irq_domain, bit);
>>>>>> +                     if (virq)
>>>>>> +                             generic_handle_irq(virq);
>>>>>> +                     else
>>>>>> +                             dev_err(dev, "unexpected INTx%u\n", bit);
>>>>>> +             }
>>>>>> +     } while ((status & SYS_RC_INTX_MASK) != 0);
>>>>
>>
>>
>>
>> -- 
>> With Best Regards,
>> Andy Shevchenko
Srinath Mannam Dec. 6, 2019, 9:44 a.m. UTC | #7
On Tue, Dec 3, 2019 at 9:25 PM Andrew Murray <andrew.murray@arm.com> wrote:
>
> On Tue, Dec 03, 2019 at 10:27:02AM +0530, Srinath Mannam wrote:
> > From: Ray Jui <ray.jui@broadcom.com>
> >
> > Add PCIe legacy interrupt INTx support to the iProc PCIe driver by
> > modeling it with its own IRQ domain. All 4 interrupts INTA, INTB, INTC,
> > INTD share the same interrupt line connected to the GIC in the system,
> > while the status of each INTx can be obtained through the INTX CSR
> > register
> >
> > Signed-off-by: Ray Jui <ray.jui@broadcom.com>
> > Signed-off-by: Srinath Mannam <srinath.mannam@broadcom.com>
> > ---
> >  drivers/pci/controller/pcie-iproc.c | 100 +++++++++++++++++++++++++++++++++++-
> >  drivers/pci/controller/pcie-iproc.h |   6 +++
> >  2 files changed, 104 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c
> > index 2d457bf..e90c22e 100644
> > --- a/drivers/pci/controller/pcie-iproc.c
> > +++ b/drivers/pci/controller/pcie-iproc.c
> > @@ -14,6 +14,7 @@
> >  #include <linux/delay.h>
> >  #include <linux/interrupt.h>
> >  #include <linux/irqchip/arm-gic-v3.h>
> > +#include <linux/irqchip/chained_irq.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/of_address.h>
> >  #include <linux/of_pci.h>
> > @@ -270,6 +271,7 @@ enum iproc_pcie_reg {
> >
> >       /* enable INTx */
> >       IPROC_PCIE_INTX_EN,
> > +     IPROC_PCIE_INTX_CSR,
> >
> >       /* outbound address mapping */
> >       IPROC_PCIE_OARR0,
> > @@ -314,6 +316,7 @@ static const u16 iproc_pcie_reg_paxb_bcma[] = {
> >       [IPROC_PCIE_CFG_ADDR]           = 0x1f8,
> >       [IPROC_PCIE_CFG_DATA]           = 0x1fc,
> >       [IPROC_PCIE_INTX_EN]            = 0x330,
> > +     [IPROC_PCIE_INTX_CSR]           = 0x334,
> >       [IPROC_PCIE_LINK_STATUS]        = 0xf0c,
> >  };
> >
> > @@ -325,6 +328,7 @@ static const u16 iproc_pcie_reg_paxb[] = {
> >       [IPROC_PCIE_CFG_ADDR]           = 0x1f8,
> >       [IPROC_PCIE_CFG_DATA]           = 0x1fc,
> >       [IPROC_PCIE_INTX_EN]            = 0x330,
> > +     [IPROC_PCIE_INTX_CSR]           = 0x334,
> >       [IPROC_PCIE_OARR0]              = 0xd20,
> >       [IPROC_PCIE_OMAP0]              = 0xd40,
> >       [IPROC_PCIE_OARR1]              = 0xd28,
> > @@ -341,6 +345,7 @@ static const u16 iproc_pcie_reg_paxb_v2[] = {
> >       [IPROC_PCIE_CFG_ADDR]           = 0x1f8,
> >       [IPROC_PCIE_CFG_DATA]           = 0x1fc,
> >       [IPROC_PCIE_INTX_EN]            = 0x330,
> > +     [IPROC_PCIE_INTX_CSR]           = 0x334,
> >       [IPROC_PCIE_OARR0]              = 0xd20,
> >       [IPROC_PCIE_OMAP0]              = 0xd40,
> >       [IPROC_PCIE_OARR1]              = 0xd28,
> > @@ -846,9 +851,95 @@ static int iproc_pcie_check_link(struct iproc_pcie *pcie)
> >       return link_is_active ? 0 : -ENODEV;
> >  }
> >
> > -static void iproc_pcie_enable(struct iproc_pcie *pcie)
> > +static int iproc_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> > +                            irq_hw_number_t hwirq)
> >  {
> > +     irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
> > +     irq_set_chip_data(irq, domain->host_data);
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct irq_domain_ops intx_domain_ops = {
> > +     .map = iproc_pcie_intx_map,
> > +};
> > +
> > +static void iproc_pcie_isr(struct irq_desc *desc)
> > +{
> > +     struct irq_chip *chip = irq_desc_get_chip(desc);
> > +     struct iproc_pcie *pcie;
> > +     struct device *dev;
> > +     unsigned long status;
> > +     u32 bit, virq;
> > +
> > +     chained_irq_enter(chip, desc);
> > +     pcie = irq_desc_get_handler_data(desc);
> > +     dev = pcie->dev;
> > +
> > +     /* go through INTx A, B, C, D until all interrupts are handled */
> > +     do {
> > +             status = iproc_pcie_read_reg(pcie, IPROC_PCIE_INTX_CSR);
>
> By performing this read once and outside of the do/while loop you may improve
> performance. I wonder how probable it is to get another INTx whilst handling
> one?
>
>
> > +             for_each_set_bit(bit, &status, PCI_NUM_INTX) {
> > +                     virq = irq_find_mapping(pcie->irq_domain, bit);
> > +                     if (virq)
> > +                             generic_handle_irq(virq);
> > +                     else
> > +                             dev_err(dev, "unexpected INTx%u\n", bit);
> > +             }
> > +     } while ((status & SYS_RC_INTX_MASK) != 0);
> > +
> > +     chained_irq_exit(chip, desc);
> > +}
> > +
> > +static int iproc_pcie_intx_enable(struct iproc_pcie *pcie)
> > +{
> > +     struct device *dev = pcie->dev;
> > +     struct device_node *node;
> > +     int ret;
> > +
> >       iproc_pcie_write_reg(pcie, IPROC_PCIE_INTX_EN, SYS_RC_INTX_MASK);
> > +     /*
> > +      * BCMA devices do not map INTx the same way as platform devices. All
> > +      * BCMA needs is the above code to enable INTx
> > +      */
>
> NIT: Move this comment above the line of code?
I will change in the next patch set.
>
>
> > +
> > +     node = of_get_compatible_child(dev->of_node, "brcm,iproc-intc");
>
> As the interrupt controller is built into the PCI controller, what is the
> rationale for representing this as a separate device tree device?
In patchset v1, PCIe controller was taken as interrupt controller
which is not correct.
So that, separate DT node was taken, based on comments below link.
https://lore.kernel.org/linux-pci/CAL_Jsq+ac6dmHKS6m0h5N3bv=VseKVL8XLU5K7j1Rn=mgFNLsA@mail.gmail.com/
>
> Thanks,
>
> Andrew Murray
>
> > +     if (node)
> > +             pcie->irq = of_irq_get(node, 0);
> > +
> > +     if (!node || pcie->irq <= 0)
> > +             return 0;
> > +
> > +     /* set IRQ handler */
> > +     irq_set_chained_handler_and_data(pcie->irq, iproc_pcie_isr, pcie);
> > +
> > +     /* add IRQ domain for INTx */
> > +     pcie->irq_domain = irq_domain_add_linear(node, PCI_NUM_INTX,
> > +                                              &intx_domain_ops, pcie);
> > +     if (!pcie->irq_domain) {
> > +             dev_err(dev, "failed to add INTx IRQ domain\n");
> > +             ret = -ENOMEM;
> > +             goto err_rm_handler_data;
> > +     }
> > +
> > +     return 0;
> > +
> > +err_rm_handler_data:
> > +     of_node_put(node);
> > +     irq_set_chained_handler_and_data(pcie->irq, NULL, NULL);
> > +
> > +     return ret;
> > +}
> > +
> > +static void iproc_pcie_intx_disable(struct iproc_pcie *pcie)
> > +{
> > +     iproc_pcie_write_reg(pcie, IPROC_PCIE_INTX_EN, 0x0);
> > +
> > +     if (pcie->irq <= 0)
> > +             return;
> > +
> > +     irq_domain_remove(pcie->irq_domain);
> > +     irq_set_chained_handler_and_data(pcie->irq, NULL, NULL);
> >  }
> >
> >  static inline bool iproc_pcie_ob_is_valid(struct iproc_pcie *pcie,
> > @@ -1537,7 +1628,11 @@ int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res)
> >               goto err_power_off_phy;
> >       }
> >
> > -     iproc_pcie_enable(pcie);
> > +     ret = iproc_pcie_intx_enable(pcie);
> > +     if (ret) {
> > +             dev_err(dev, "failed to enable INTx\n");
> > +             goto err_power_off_phy;
> > +     }
> >
> >       if (IS_ENABLED(CONFIG_PCI_MSI))
> >               if (iproc_pcie_msi_enable(pcie))
> > @@ -1582,6 +1677,7 @@ int iproc_pcie_remove(struct iproc_pcie *pcie)
> >       pci_remove_root_bus(pcie->root_bus);
> >
> >       iproc_pcie_msi_disable(pcie);
> > +     iproc_pcie_intx_disable(pcie);
> >
> >       phy_power_off(pcie->phy);
> >       phy_exit(pcie->phy);
> > diff --git a/drivers/pci/controller/pcie-iproc.h b/drivers/pci/controller/pcie-iproc.h
> > index 4f03ea5..103e568 100644
> > --- a/drivers/pci/controller/pcie-iproc.h
> > +++ b/drivers/pci/controller/pcie-iproc.h
> > @@ -74,6 +74,9 @@ struct iproc_msi;
> >   * @ib: inbound mapping related parameters
> >   * @ib_map: outbound mapping region related parameters
> >   *
> > + * @irq: interrupt line wired to the generic GIC for INTx
> > + * @irq_domain: IRQ domain for INTx
> > + *
> >   * @need_msi_steer: indicates additional configuration of the iProc PCIe
> >   * controller is required to steer MSI writes to external interrupt controller
> >   * @msi: MSI data
> > @@ -102,6 +105,9 @@ struct iproc_pcie {
> >       struct iproc_pcie_ib ib;
> >       const struct iproc_pcie_ib_map *ib_map;
> >
> > +     int irq;
> > +     struct irq_domain *irq_domain;
> > +
> >       bool need_msi_steer;
> >       struct iproc_msi *msi;
> >  };
> > --
> > 2.7.4
> >

Patch
diff mbox series

diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c
index 2d457bf..e90c22e 100644
--- a/drivers/pci/controller/pcie-iproc.c
+++ b/drivers/pci/controller/pcie-iproc.c
@@ -14,6 +14,7 @@ 
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/irqchip/arm-gic-v3.h>
+#include <linux/irqchip/chained_irq.h>
 #include <linux/platform_device.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
@@ -270,6 +271,7 @@  enum iproc_pcie_reg {
 
 	/* enable INTx */
 	IPROC_PCIE_INTX_EN,
+	IPROC_PCIE_INTX_CSR,
 
 	/* outbound address mapping */
 	IPROC_PCIE_OARR0,
@@ -314,6 +316,7 @@  static const u16 iproc_pcie_reg_paxb_bcma[] = {
 	[IPROC_PCIE_CFG_ADDR]		= 0x1f8,
 	[IPROC_PCIE_CFG_DATA]		= 0x1fc,
 	[IPROC_PCIE_INTX_EN]		= 0x330,
+	[IPROC_PCIE_INTX_CSR]		= 0x334,
 	[IPROC_PCIE_LINK_STATUS]	= 0xf0c,
 };
 
@@ -325,6 +328,7 @@  static const u16 iproc_pcie_reg_paxb[] = {
 	[IPROC_PCIE_CFG_ADDR]		= 0x1f8,
 	[IPROC_PCIE_CFG_DATA]		= 0x1fc,
 	[IPROC_PCIE_INTX_EN]		= 0x330,
+	[IPROC_PCIE_INTX_CSR]		= 0x334,
 	[IPROC_PCIE_OARR0]		= 0xd20,
 	[IPROC_PCIE_OMAP0]		= 0xd40,
 	[IPROC_PCIE_OARR1]		= 0xd28,
@@ -341,6 +345,7 @@  static const u16 iproc_pcie_reg_paxb_v2[] = {
 	[IPROC_PCIE_CFG_ADDR]		= 0x1f8,
 	[IPROC_PCIE_CFG_DATA]		= 0x1fc,
 	[IPROC_PCIE_INTX_EN]		= 0x330,
+	[IPROC_PCIE_INTX_CSR]		= 0x334,
 	[IPROC_PCIE_OARR0]		= 0xd20,
 	[IPROC_PCIE_OMAP0]		= 0xd40,
 	[IPROC_PCIE_OARR1]		= 0xd28,
@@ -846,9 +851,95 @@  static int iproc_pcie_check_link(struct iproc_pcie *pcie)
 	return link_is_active ? 0 : -ENODEV;
 }
 
-static void iproc_pcie_enable(struct iproc_pcie *pcie)
+static int iproc_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
+			       irq_hw_number_t hwirq)
 {
+	irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
+	irq_set_chip_data(irq, domain->host_data);
+
+	return 0;
+}
+
+static const struct irq_domain_ops intx_domain_ops = {
+	.map = iproc_pcie_intx_map,
+};
+
+static void iproc_pcie_isr(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct iproc_pcie *pcie;
+	struct device *dev;
+	unsigned long status;
+	u32 bit, virq;
+
+	chained_irq_enter(chip, desc);
+	pcie = irq_desc_get_handler_data(desc);
+	dev = pcie->dev;
+
+	/* go through INTx A, B, C, D until all interrupts are handled */
+	do {
+		status = iproc_pcie_read_reg(pcie, IPROC_PCIE_INTX_CSR);
+		for_each_set_bit(bit, &status, PCI_NUM_INTX) {
+			virq = irq_find_mapping(pcie->irq_domain, bit);
+			if (virq)
+				generic_handle_irq(virq);
+			else
+				dev_err(dev, "unexpected INTx%u\n", bit);
+		}
+	} while ((status & SYS_RC_INTX_MASK) != 0);
+
+	chained_irq_exit(chip, desc);
+}
+
+static int iproc_pcie_intx_enable(struct iproc_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	struct device_node *node;
+	int ret;
+
 	iproc_pcie_write_reg(pcie, IPROC_PCIE_INTX_EN, SYS_RC_INTX_MASK);
+	/*
+	 * BCMA devices do not map INTx the same way as platform devices. All
+	 * BCMA needs is the above code to enable INTx
+	 */
+
+	node = of_get_compatible_child(dev->of_node, "brcm,iproc-intc");
+	if (node)
+		pcie->irq = of_irq_get(node, 0);
+
+	if (!node || pcie->irq <= 0)
+		return 0;
+
+	/* set IRQ handler */
+	irq_set_chained_handler_and_data(pcie->irq, iproc_pcie_isr, pcie);
+
+	/* add IRQ domain for INTx */
+	pcie->irq_domain = irq_domain_add_linear(node, PCI_NUM_INTX,
+						 &intx_domain_ops, pcie);
+	if (!pcie->irq_domain) {
+		dev_err(dev, "failed to add INTx IRQ domain\n");
+		ret = -ENOMEM;
+		goto err_rm_handler_data;
+	}
+
+	return 0;
+
+err_rm_handler_data:
+	of_node_put(node);
+	irq_set_chained_handler_and_data(pcie->irq, NULL, NULL);
+
+	return ret;
+}
+
+static void iproc_pcie_intx_disable(struct iproc_pcie *pcie)
+{
+	iproc_pcie_write_reg(pcie, IPROC_PCIE_INTX_EN, 0x0);
+
+	if (pcie->irq <= 0)
+		return;
+
+	irq_domain_remove(pcie->irq_domain);
+	irq_set_chained_handler_and_data(pcie->irq, NULL, NULL);
 }
 
 static inline bool iproc_pcie_ob_is_valid(struct iproc_pcie *pcie,
@@ -1537,7 +1628,11 @@  int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res)
 		goto err_power_off_phy;
 	}
 
-	iproc_pcie_enable(pcie);
+	ret = iproc_pcie_intx_enable(pcie);
+	if (ret) {
+		dev_err(dev, "failed to enable INTx\n");
+		goto err_power_off_phy;
+	}
 
 	if (IS_ENABLED(CONFIG_PCI_MSI))
 		if (iproc_pcie_msi_enable(pcie))
@@ -1582,6 +1677,7 @@  int iproc_pcie_remove(struct iproc_pcie *pcie)
 	pci_remove_root_bus(pcie->root_bus);
 
 	iproc_pcie_msi_disable(pcie);
+	iproc_pcie_intx_disable(pcie);
 
 	phy_power_off(pcie->phy);
 	phy_exit(pcie->phy);
diff --git a/drivers/pci/controller/pcie-iproc.h b/drivers/pci/controller/pcie-iproc.h
index 4f03ea5..103e568 100644
--- a/drivers/pci/controller/pcie-iproc.h
+++ b/drivers/pci/controller/pcie-iproc.h
@@ -74,6 +74,9 @@  struct iproc_msi;
  * @ib: inbound mapping related parameters
  * @ib_map: outbound mapping region related parameters
  *
+ * @irq: interrupt line wired to the generic GIC for INTx
+ * @irq_domain: IRQ domain for INTx
+ *
  * @need_msi_steer: indicates additional configuration of the iProc PCIe
  * controller is required to steer MSI writes to external interrupt controller
  * @msi: MSI data
@@ -102,6 +105,9 @@  struct iproc_pcie {
 	struct iproc_pcie_ib ib;
 	const struct iproc_pcie_ib_map *ib_map;
 
+	int irq;
+	struct irq_domain *irq_domain;
+
 	bool need_msi_steer;
 	struct iproc_msi *msi;
 };