[PATCH v3 08/24] irqchip/irq-msi-lib: Prepare for DEVICE MSI to replace platform MSI

[Shivamurthy Shastri]

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Add the prerequisites for DEVICE MSI into the shared select() and child
domain init function. These domains are really trivial and just provide a
custom irq chip callback to write the MSI message.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Anna-Maria Behnsen <anna-maria@xxxxxxxxxxxxx>
Signed-off-by: Shivamurthy Shastri <shivamurthy.shastri@xxxxxxxxxxxxx>
---
v3: adopted to IMS->MSI rename
---
 drivers/irqchip/irq-msi-lib.c | 13 +++++++++++++
 drivers/irqchip/irq-msi-lib.h |  2 ++
 2 files changed, 15 insertions(+)

diff --git a/drivers/irqchip/irq-msi-lib.c b/drivers/irqchip/irq-msi-lib.c
index 0b359c5d8c6c..6aa4974d2d12 100644
--- a/drivers/irqchip/irq-msi-lib.c
+++ b/drivers/irqchip/irq-msi-lib.c
@@ -53,6 +53,19 @@ bool msi_lib_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
 		if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PCI_MSI)))
 			return false;
 
+		break;
+	case DOMAIN_BUS_DEVICE_MSI:
+		/*
+		 * Per device MSI should never have any MSI feature bits
+		 * set. It's sole purpose is to create a dumb interrupt
+		 * chip which has a device specific irq_write_msi_msg()
+		 * callback.
+		 */
+		if (WARN_ON_ONCE(info->flags))
+			return false;
+
+		/* Core managed MSI descriptors */
+		info->flags = MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS | MSI_FLAG_FREE_MSI_DESCS;
 		break;
 	default:
 		/*
diff --git a/drivers/irqchip/irq-msi-lib.h b/drivers/irqchip/irq-msi-lib.h
index 525aa5284a99..681ceabb7bc7 100644
--- a/drivers/irqchip/irq-msi-lib.h
+++ b/drivers/irqchip/irq-msi-lib.h
@@ -15,6 +15,8 @@
 #define MATCH_PCI_MSI		(0)
 #endif
 
+#define MATCH_PLATFORM_MSI	BIT(DOMAIN_BUS_PLATFORM_MSI)
+
 int msi_lib_irq_domain_select(struct irq_domain *d, struct irq_fwspec *fwspec,
 			      enum irq_domain_bus_token bus_token);
 
-- 
2.34.1