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. This 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 affects every platform 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 <[email protected]>

---
Changes since v2:
- No need for a loop to find #interrupt-cells property value
- Fix node de-reference leak when index is greater than number of entries in interrupt-map property
Changes since v1:
- Updated commit description based on Rob's suggestion
- Use of_irq_parse_raw() for parsing interrupt-map DT property

---
 drivers/of/property.c | 50 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

drivers/of/property.c +25 -0

index a6358ee99b74..7326ca07adfe 100644
@@ -1311,6 +1311,55 @@ 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)
+{
+       const __be32 *imap, *imap_end, *addr;
+       struct of_phandle_args sup_args;
+       u32 addrcells, intcells;
+       int i, imaplen;
+
+       if (!IS_ENABLED(CONFIG_OF_IRQ))
+               return NULL;
+
+       if (strcmp(prop_name, "interrupt-map"))
+               return NULL;
+
+       if (of_property_read_u32(np, "#interrupt-cells", &intcells))
+               return NULL;
+       addrcells = of_bus_n_addr_cells(np);
+
+       imap = of_get_property(np, "interrupt-map", &imaplen);
+       if (!imap || imaplen <= (addrcells + intcells))
+               return NULL;
+       imap_end = imap + imaplen;
+
+       sup_args.np = NULL;
+       while (imap < imap_end) {

drivers/of/property.c +8 -1

+               imap += sup_args.args_count + 1;
+               index--;
+       }
+
+       return NULL;
+}
+
 static struct device_node *parse_remote_endpoint(struct device_node *np,
                                                 const char *prop_name,
                                                 int index)

@@ -1359,6 +1408,7 @@ 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, },
--

2.34.1

Quoted 66 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. This 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 affects every platform 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 <[email protected]>

---
Changes since v2:
- No need for a loop to find #interrupt-cells property value
- Fix node de-reference leak when index is greater than number of entries in interrupt-map property
Changes since v1:
- Updated commit description based on Rob's suggestion
- Use of_irq_parse_raw() for parsing interrupt-map DT property

---
 drivers/of/property.c | 50 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

drivers/of/property.c +30 -0

index a6358ee99b74..7326ca07adfe 100644
@@ -1311,6 +1311,55 @@ 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)
+{
+       const __be32 *imap, *imap_end, *addr;
+       struct of_phandle_args sup_args;
+       u32 addrcells, intcells;
+       int i, imaplen;
+
+       if (!IS_ENABLED(CONFIG_OF_IRQ))
+               return NULL;
+
+       if (strcmp(prop_name, "interrupt-map"))
+               return NULL;
+
+       if (of_property_read_u32(np, "#interrupt-cells", &intcells))
+               return NULL;
+       addrcells = of_bus_n_addr_cells(np);
+
+       imap = of_get_property(np, "interrupt-map", &imaplen);
+       if (!imap || imaplen <= (addrcells + intcells))
+               return NULL;
+       imap_end = imap + imaplen;
+
+       sup_args.np = NULL;
+       while (imap < imap_end) {
+               addr = imap;
+               imap += addrcells;
+
+               sup_args.np = np;
+               sup_args.args_count = intcells;

drivers/of/property.c static struct device_node *parse_interrupts(struct device_node *np, · line 1348

Quoted 5 lines

drivers/of/property.c +5 -0

+               for (i = 0; i < intcells; i++)
+                       sup_args.args[i] = be32_to_cpu(imap[i]);
+               imap += intcells;
+
+               if (of_irq_parse_raw(addr, &sup_args))

Can you leave a comment above this call saying of_irq_parse_raw() updates sup_args.np? It's really a problem with the function IMO, but a comment here would be helpful.

drivers/of/property.c static struct device_node *parse_interrupts(struct device_node *np, · line 1355

Quoted 8 lines

drivers/of/property.c +7 -0

+                       return NULL;
+
+               if (!index)
+                       return sup_args.np;
+
+               of_node_put(sup_args.np);
+               sup_args.np = NULL;

Why do you need to set it to NULL? Can we just delete this line?

If you take care of these minor comments, then

Reviewed-by Saravana Kannan <[email protected]>

-Saravana

Quoted 13 lines

drivers/of/property.c +7 -0

+               imap += sup_args.args_count + 1;
+               index--;
+       }
+
+       return NULL;
+}
+
 static struct device_node *parse_remote_endpoint(struct device_node *np,
                                                 const char *prop_name,
                                                 int index)

@@ -1359,6 +1408,7 @@ static const struct supplier_bindings of_supplier_bindings[] = {
        { .parse_prop = parse_msi_parent, },
        { .parse_prop = parse_gpio_compat, },

Quoted 8 lines

drivers/of/property.c +1 -1

        { .parse_prop = parse_interrupts, },
+       { .parse_prop = parse_interrupt_map, },
        { .parse_prop = parse_regulators, },
        { .parse_prop = parse_gpio, },
        { .parse_prop = parse_gpios, },
--

2.34.1