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. See below figure.
┌────────────────────────────────┐
│ │
│ PCI Endpoint Controller │
│ │
│ ┌─────┐ ┌─────┐ ┌─────┐ │
PCI Bus │ │ │ │ │ │ │ │
─────────► │ │Func1│ │Func2│ ... │Func │ │
TLP Memory │ │ │ │ │ │<n> │ │
Write Push │ │ │ │ │ │ │ │
DoorBell │ └─┬─┬─┘ └──┬──┘ └──┬──┘ │
│ │ │ │ │ │
└────┼─┼────────┼───────────┼────┘
sideband │ │ Address│ │
information ▼ ▼ /Data ▼ ▼
┌────────────────────────┐
│ MSI Controller │
└────────────────────────┘
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@xxxxxxx>
---
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 e150365fbe892..6c7389bb84a4a 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
