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of: property: Add fw_devlink support for interrupt-map property

Message ID 20240412112931.285507-1-apatel@ventanamicro.com
State Changes Requested
Headers show
Series of: property: Add fw_devlink support for interrupt-map property | expand

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Commit Message

Anup Patel April 12, 2024, 11:29 a.m. UTC
Some of the PCI controllers (such as generic PCI host controller)
use "interrupt-map" DT property to describe the mapping between
PCI endpoints and PCI interrupt pins.

Currently, there is no fw_devlink created based on "interrupt-map"
DT property so interrupt controller is not guaranteed to be probed
before PCI host controller. This mainly affects RISC-V platforms
where both PCI host controller and interrupt controllers are probed
as regular platform devices.

This creates fw_devlink between consumers (PCI host controller) and
supplier (interrupt controller) based on "interrupt-map" DT property.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
 drivers/of/property.c | 53 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

Comments

Rob Herring April 12, 2024, 12:37 p.m. UTC | #1
On Fri, Apr 12, 2024 at 6:29 AM Anup Patel <apatel@ventanamicro.com> wrote:
>
> Some of the PCI controllers (such as generic PCI host controller)
> use "interrupt-map" DT property to describe the mapping between
> PCI endpoints and PCI interrupt pins.

I would go as far as saying that's the only case as that's the only
case where the interrupts are not described in DT.

> Currently, there is no fw_devlink created based on "interrupt-map"
> DT property so interrupt controller is not guaranteed to be probed
> before PCI host controller. This mainly affects RISC-V platforms
> where both PCI host controller and interrupt controllers are probed
> as regular platform devices.

That's *every* system with PCI really.

> This creates fw_devlink between consumers (PCI host controller) and
> supplier (interrupt controller) based on "interrupt-map" DT property.
>
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
>  drivers/of/property.c | 53 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
>
> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index a6358ee99b74..ccbbb651a89a 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -1311,6 +1311,58 @@ static struct device_node *parse_interrupts(struct device_node *np,
>         return of_irq_parse_one(np, index, &sup_args) ? NULL : sup_args.np;
>  }
>
> +static struct device_node *parse_interrupt_map(struct device_node *np,
> +                                              const char *prop_name, int index)
> +{
> +       struct device_node *tn, *ipar, *supnp = NULL;
> +       u32 addrcells, intcells, cells;
> +       const __be32 *imap, *imap_end;
> +       int i, imaplen;
> +
> +       if (!IS_ENABLED(CONFIG_OF_IRQ))
> +               return NULL;
> +
> +       if (strcmp(prop_name, "interrupt-map"))
> +               return NULL;
> +
> +       ipar = of_node_get(np);
> +       do {
> +               if (!of_property_read_u32(ipar, "#interrupt-cells", &intcells))
> +                       break;
> +               tn = ipar;
> +               ipar = of_irq_find_parent(ipar);
> +               of_node_put(tn);
> +       } while (ipar);
> +       if (!ipar)
> +               return NULL;
> +       addrcells = of_bus_n_addr_cells(ipar);
> +       of_node_put(ipar);
> +
> +       imap = of_get_property(np, "interrupt-map", &imaplen);
> +       if (!imap || imaplen <= (addrcells + intcells))
> +               return NULL;
> +       imap_end = imap + imaplen;
> +
> +       for (i = 0; i <= index && imap < imap_end; i++) {
> +               if (supnp)
> +                       of_node_put(supnp);
> +
> +               imap += addrcells;
> +               imap += intcells;
> +
> +               supnp = of_find_node_by_phandle(be32_to_cpu(imap[0]));
> +               if (!supnp)
> +                       return NULL;
> +               imap += 1;
> +
> +               if (of_property_read_u32(supnp, "#interrupt-cells", &cells))
> +                       return NULL;
> +               imap += cells;

This is wrong. Technically, you can have #address-cells too.

The bigger problem I have is this creates 2 sets of 'interrupt-map'
parsing code. Your version skips a lot of things like whether the
interrupt controller is available and there's the list of
'interrupt-map' abusers to think about.

Rob
Anup Patel April 12, 2024, 1:50 p.m. UTC | #2
On Fri, Apr 12, 2024 at 6:07 PM Rob Herring <robh@kernel.org> wrote:
>
> On Fri, Apr 12, 2024 at 6:29 AM Anup Patel <apatel@ventanamicro.com> wrote:
> >
> > Some of the PCI controllers (such as generic PCI host controller)
> > use "interrupt-map" DT property to describe the mapping between
> > PCI endpoints and PCI interrupt pins.
>
> I would go as far as saying that's the only case as that's the only
> case where the interrupts are not described in DT.

Sure, I will update the text.

>
> > Currently, there is no fw_devlink created based on "interrupt-map"
> > DT property so interrupt controller is not guaranteed to be probed
> > before PCI host controller. This mainly affects RISC-V platforms
> > where both PCI host controller and interrupt controllers are probed
> > as regular platform devices.
>
> That's *every* system with PCI really.

Okay, I will re-word.

>
> > This creates fw_devlink between consumers (PCI host controller) and
> > supplier (interrupt controller) based on "interrupt-map" DT property.
> >
> > Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> > ---
> >  drivers/of/property.c | 53 +++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 53 insertions(+)
> >
> > diff --git a/drivers/of/property.c b/drivers/of/property.c
> > index a6358ee99b74..ccbbb651a89a 100644
> > --- a/drivers/of/property.c
> > +++ b/drivers/of/property.c
> > @@ -1311,6 +1311,58 @@ static struct device_node *parse_interrupts(struct device_node *np,
> >         return of_irq_parse_one(np, index, &sup_args) ? NULL : sup_args.np;
> >  }
> >
> > +static struct device_node *parse_interrupt_map(struct device_node *np,
> > +                                              const char *prop_name, int index)
> > +{
> > +       struct device_node *tn, *ipar, *supnp = NULL;
> > +       u32 addrcells, intcells, cells;
> > +       const __be32 *imap, *imap_end;
> > +       int i, imaplen;
> > +
> > +       if (!IS_ENABLED(CONFIG_OF_IRQ))
> > +               return NULL;
> > +
> > +       if (strcmp(prop_name, "interrupt-map"))
> > +               return NULL;
> > +
> > +       ipar = of_node_get(np);
> > +       do {
> > +               if (!of_property_read_u32(ipar, "#interrupt-cells", &intcells))
> > +                       break;
> > +               tn = ipar;
> > +               ipar = of_irq_find_parent(ipar);
> > +               of_node_put(tn);
> > +       } while (ipar);
> > +       if (!ipar)
> > +               return NULL;
> > +       addrcells = of_bus_n_addr_cells(ipar);
> > +       of_node_put(ipar);
> > +
> > +       imap = of_get_property(np, "interrupt-map", &imaplen);
> > +       if (!imap || imaplen <= (addrcells + intcells))
> > +               return NULL;
> > +       imap_end = imap + imaplen;
> > +
> > +       for (i = 0; i <= index && imap < imap_end; i++) {
> > +               if (supnp)
> > +                       of_node_put(supnp);
> > +
> > +               imap += addrcells;
> > +               imap += intcells;
> > +
> > +               supnp = of_find_node_by_phandle(be32_to_cpu(imap[0]));
> > +               if (!supnp)
> > +                       return NULL;
> > +               imap += 1;
> > +
> > +               if (of_property_read_u32(supnp, "#interrupt-cells", &cells))
> > +                       return NULL;
> > +               imap += cells;
>
> This is wrong. Technically, you can have #address-cells too.
>
> The bigger problem I have is this creates 2 sets of 'interrupt-map'
> parsing code. Your version skips a lot of things like whether the
> interrupt controller is available and there's the list of
> 'interrupt-map' abusers to think about.
>

In my first attempt, I was trying to keep it simple but I guess I
over-simplified it.

I have an alternate approach to use of_irq_parse_raw() over
here (similar to of_irq_parse_pci() in drivers/pci/of.c). Are you
okay with this approach ?

Regards,
Anup
diff mbox series

Patch

diff --git a/drivers/of/property.c b/drivers/of/property.c
index a6358ee99b74..ccbbb651a89a 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1311,6 +1311,58 @@  static struct device_node *parse_interrupts(struct device_node *np,
 	return of_irq_parse_one(np, index, &sup_args) ? NULL : sup_args.np;
 }
 
+static struct device_node *parse_interrupt_map(struct device_node *np,
+					       const char *prop_name, int index)
+{
+	struct device_node *tn, *ipar, *supnp = NULL;
+	u32 addrcells, intcells, cells;
+	const __be32 *imap, *imap_end;
+	int i, imaplen;
+
+	if (!IS_ENABLED(CONFIG_OF_IRQ))
+		return NULL;
+
+	if (strcmp(prop_name, "interrupt-map"))
+		return NULL;
+
+	ipar = of_node_get(np);
+	do {
+		if (!of_property_read_u32(ipar, "#interrupt-cells", &intcells))
+			break;
+		tn = ipar;
+		ipar = of_irq_find_parent(ipar);
+		of_node_put(tn);
+	} while (ipar);
+	if (!ipar)
+		return NULL;
+	addrcells = of_bus_n_addr_cells(ipar);
+	of_node_put(ipar);
+
+	imap = of_get_property(np, "interrupt-map", &imaplen);
+	if (!imap || imaplen <= (addrcells + intcells))
+		return NULL;
+	imap_end = imap + imaplen;
+
+	for (i = 0; i <= index && imap < imap_end; i++) {
+		if (supnp)
+			of_node_put(supnp);
+
+		imap += addrcells;
+		imap += intcells;
+
+		supnp = of_find_node_by_phandle(be32_to_cpu(imap[0]));
+		if (!supnp)
+			return NULL;
+		imap += 1;
+
+		if (of_property_read_u32(supnp, "#interrupt-cells", &cells))
+			return NULL;
+		imap += cells;
+	}
+
+	return supnp;
+}
+
 static struct device_node *parse_remote_endpoint(struct device_node *np,
 						 const char *prop_name,
 						 int index)
@@ -1359,6 +1411,7 @@  static const struct supplier_bindings of_supplier_bindings[] = {
 	{ .parse_prop = parse_msi_parent, },
 	{ .parse_prop = parse_gpio_compat, },
 	{ .parse_prop = parse_interrupts, },
+	{ .parse_prop = parse_interrupt_map, },
 	{ .parse_prop = parse_regulators, },
 	{ .parse_prop = parse_gpio, },
 	{ .parse_prop = parse_gpios, },