[PATCH v18 05/15] irqchip/gic-v3-its: Add support for device tree msi-map and msi-mask

Frank Li
2025-04-14T18:31:45Z

Some platform devices create child devices dynamically and require the
parent device's msi-map to map device IDs to actual sideband information.

A typical use case is using ITS as a PCIe Endpoint Controller(EPC)'s
doorbell function, where PCI hosts send TLP memory writes to the EP
controller. The EP controller converts these writes to AXI transactions
and appends platform-specific sideband information.

EPC's DTS will provide such information by msi-map and msi-mask. A
simplified dts as

pcie-ep@10000000 {
...
msi-map = <0 &its 0xc 8>;
^^^ 0xc is implement defined sideband information,
which append to AXI write transaction.
^ 0 is function index.

msi-mask = <0x7>
}

Check msi-map if msi-parent missed to keep compatility with existed system.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
change from v15 to v16
- remove ascii figures in commit message

change from v14 to v15
- none

change from v13 to v14
new patch
---
drivers/irqchip/irq-gic-v3-its-msi-parent.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its-msi-parent.c b/drivers/irqchip/irq-gic-v3-its-msi-parent.c
index bdb04c8081480..68f9ba4085ce5 100644
--- a/drivers/irqchip/irq-gic-v3-its-msi-parent.c
+++ b/drivers/irqchip/irq-gic-v3-its-msi-parent.c
@@ -118,6 +118,14 @@ static int of_pmsi_get_dev_id(struct irq_domain *domain, struct device *dev,
index++;
} while (!ret);

+ if (ret) {
+ struct device_node *np = NULL;
+
+ ret = of_map_id(dev->of_node, dev->id, "msi-map", "msi-map-mask", &np, dev_id);
+ if (np)
+ of_node_put(np);
+ }
+
return ret;
}

--
2.34.1