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@nxp.com --- 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; }