[PATCH v13 1/9] genirq/msi: Provide DOMAIN_BUS_PLATFORM_PCI_EP_MSI

[Frank Li <Frank.Li@xxxxxxx>]

           ┌────────────────────────────────┐
           │                                │
           │     PCI Endpoint Controller    │
           │                                │
           │   ┌─────┐  ┌─────┐     ┌─────┐ │
PCI Bus    │   │     │  │     │     │     │ │
─────────► │   │Func1│  │Func2│ ... │Func │ │
Doorbell   │   │     │  │     │     │<n>  │ │
           │   │     │  │     │     │     │ │
           │   └──┬──┘  └──┬──┘     └──┬──┘ │
           │      │        │           │    │
           └──────┼────────┼───────────┼────┘
                  │        │           │
                  ▼        ▼           ▼
               ┌────────────────────────┐
               │    MSI Controller      │
               └────────────────────────┘

Add domain BUS_PLATFORM_PCI_EP_MSI to allocate MSI domain for Endpoint
function in PCI Endpoint (EP) controller, So PCI Root Complex (RC) can
write MSI message to MSI controller to trigger doorbell IRQ for difference
EP functions.

Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
change from v12 to v13
- new patch
---
 drivers/irqchip/irq-msi-lib.c  | 4 ++++
 drivers/irqchip/irq-msi-lib.h  | 6 ++++++
 include/linux/irqdomain_defs.h | 2 ++
 3 files changed, 12 insertions(+)

diff --git a/drivers/irqchip/irq-msi-lib.c b/drivers/irqchip/irq-msi-lib.c
index d8e29fc0d4068..cf39f2e481477 100644
--- a/drivers/irqchip/irq-msi-lib.c
+++ b/drivers/irqchip/irq-msi-lib.c
@@ -57,6 +57,10 @@ bool msi_lib_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
 			return false;
 
 		break;
+	case DOMAIN_BUS_DEVICE_PCI_EP_MSI:
+		if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PCI_ENDPOINT)))
+			return false;
+		fallthrough;
 	case DOMAIN_BUS_DEVICE_MSI:
 		/*
 		 * Per device MSI should never have any MSI feature bits
diff --git a/drivers/irqchip/irq-msi-lib.h b/drivers/irqchip/irq-msi-lib.h
index 681ceabb7bc74..5ccfdb14fce1d 100644
--- a/drivers/irqchip/irq-msi-lib.h
+++ b/drivers/irqchip/irq-msi-lib.h
@@ -17,6 +17,12 @@
 
 #define MATCH_PLATFORM_MSI	BIT(DOMAIN_BUS_PLATFORM_MSI)
 
+#ifdef CONFIG_PCI_ENDPOINT
+#define MATCH_PLATFORM_PCI_EP_MSI	BIT(DOMAIN_BUS_PLATFORM_PCI_EP_MSI)
+#else
+#define MATCH_PLATFORM_PCI_EP_MSI	(0)
+#endif
+
 int msi_lib_irq_domain_select(struct irq_domain *d, struct irq_fwspec *fwspec,
 			      enum irq_domain_bus_token bus_token);
 
diff --git a/include/linux/irqdomain_defs.h b/include/linux/irqdomain_defs.h
index 36653e2ee1c92..feecbc27c2575 100644
--- a/include/linux/irqdomain_defs.h
+++ b/include/linux/irqdomain_defs.h
@@ -15,6 +15,7 @@ enum irq_domain_bus_token {
 	DOMAIN_BUS_GENERIC_MSI,
 	DOMAIN_BUS_PCI_MSI,
 	DOMAIN_BUS_PLATFORM_MSI,
+	DOMAIN_BUS_PLATFORM_PCI_EP_MSI,
 	DOMAIN_BUS_NEXUS,
 	DOMAIN_BUS_IPI,
 	DOMAIN_BUS_FSL_MC_MSI,
@@ -27,6 +28,7 @@ enum irq_domain_bus_token {
 	DOMAIN_BUS_AMDVI,
 	DOMAIN_BUS_DEVICE_MSI,
 	DOMAIN_BUS_WIRED_TO_MSI,
+	DOMAIN_BUS_DEVICE_PCI_EP_MSI,
 };
 
 #endif /* _LINUX_IRQDOMAIN_DEFS_H */

-- 
2.34.1