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

PATCH Superseded Anup Patel 2 participants 3 messages Apr 12, 2024

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v1 of 4 Superseded Latest is v4 →

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Anup Patel

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#0 lore raw

PATCH 1/1 of: property: Add fw_devlink support for interrupt-map property

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.

---
 drivers/of/property.c | 53 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
drivers/of/property.c +53 -0
index a6358ee99b74..ccbbb651a89a 100644
@@ -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, },
Signature · 1 line
2.34.1
maintainer
#1 lore raw
Quoted 4 lines · Anup Patel

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.

Quoted 5 lines

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.

Quoted 53 lines

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

---
 drivers/of/property.c | 53 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
drivers/of/property.c +37 -0
index a6358ee99b74..ccbbb651a89a 100644
@@ -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;

drivers/of/property.c static struct device_node *parse_interrupts(struct device_node *np, · line 1360

Quoted 10 lines
drivers/of/property.c +10 -0
+               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

author
#2 lore raw
Quoted 9 lines · Rob Herring
Quoted 4 lines · Anup Patel

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.

Quoted 8 lines
Quoted 6 lines

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.

Quoted 67 lines
Quoted 54 lines

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

---
 drivers/of/property.c | 53 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
drivers/of/property.c +37 -0
index a6358ee99b74..ccbbb651a89a 100644
@@ -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;

drivers/of/property.c static struct device_node *parse_interrupts(struct device_node *np, · line 1360

Quoted 10 lines
drivers/of/property.c +10 -0
+               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.

Quoted 5 lines

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