[PATCH v13 4/9] irqchip/gic-v3-its: Add DOMAIN_BUS_DEVICE_PCI_EP_MSI support

[Frank Li <Frank.Li@xxxxxxx>]

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

Add domain DOMAIN_BUS_DEVICE_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-gic-v3-its-msi-parent.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its-msi-parent.c b/drivers/irqchip/irq-gic-v3-its-msi-parent.c
index b2a4b67545b82..16e7d53f0b133 100644
--- a/drivers/irqchip/irq-gic-v3-its-msi-parent.c
+++ b/drivers/irqchip/irq-gic-v3-its-msi-parent.c
@@ -5,6 +5,7 @@
 // Copyright (C) 2022 Intel
 
 #include <linux/acpi_iort.h>
+#include <linux/pci-ep-msi.h>
 #include <linux/pci.h>
 
 #include "irq-gic-common.h"
@@ -173,6 +174,19 @@ static int its_pmsi_prepare(struct irq_domain *domain, struct device *dev,
 	return its_pmsi_prepare_devid(domain, dev, nvec, info, dev_id);
 }
 
+static int its_pci_ep_msi_prepare(struct irq_domain *domain, struct device *dev,
+				  int nvec, msi_alloc_info_t *info)
+{
+	u32 dev_id;
+	int ret;
+
+	ret = pci_epf_msi_domain_get_msi_rid(dev, &dev_id);
+	if (ret)
+		return ret;
+
+	return its_pmsi_prepare_devid(domain, dev, nvec, info, dev_id);
+}
+
 static bool its_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
 				  struct irq_domain *real_parent, struct msi_domain_info *info)
 {
@@ -205,6 +219,9 @@ static bool its_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
 		 */
 		info->ops->msi_prepare = its_pmsi_prepare;
 		break;
+	case DOMAIN_BUS_DEVICE_PCI_EP_MSI:
+		info->ops->msi_prepare = its_pci_ep_msi_prepare;
+		break;
 	default:
 		/* Confused. How did the lib return true? */
 		WARN_ON_ONCE(1);
@@ -218,7 +235,7 @@ const struct msi_parent_ops gic_v3_its_msi_parent_ops = {
 	.supported_flags	= ITS_MSI_FLAGS_SUPPORTED,
 	.required_flags		= ITS_MSI_FLAGS_REQUIRED,
 	.bus_select_token	= DOMAIN_BUS_NEXUS,
-	.bus_select_mask	= MATCH_PCI_MSI | MATCH_PLATFORM_MSI,
+	.bus_select_mask	= MATCH_PCI_MSI | MATCH_PLATFORM_MSI | MATCH_PLATFORM_PCI_EP_MSI,
 	.prefix			= "ITS-",
 	.init_dev_msi_info	= its_init_dev_msi_info,
 };

-- 
2.34.1