cdx: add MSI support for CDX bus

Add CDX-MSI domain per CDX controller with gic-its domain as
a parent, to support MSI for CDX devices. CDX devices allocate
MSIs from the CDX domain. Also, introduce APIs to alloc and free
IRQs for CDX domain.

In CDX subsystem firmware is a controller for all devices and
their configuration. CDX bus controller sends all the write_msi_msg
commands to firmware running on RPU and the firmware interfaces with
actual devices to pass this information to devices

Since, CDX controller is the only way to communicate with the Firmware
for MSI write info, CDX domain per controller required in contrast to
having a CDX domain per device.

Co-developed-by: Nikhil Agarwal <nikhil.agarwal@amd.com>
Signed-off-by: Nikhil Agarwal <nikhil.agarwal@amd.com>
Co-developed-by: Abhijit Gangurde <abhijit.gangurde@amd.com>
Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com>
Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nikhil Agarwal <nikhil.agarwal@amd.com>
Link: https://lore.kernel.org/r/20240226082816.100872-1-nipun.gupta@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 52 insertions, 1 deletions

diff --git a/include/linux/cdx/cdx_bus.h b/include/linux/cdx/cdx_bus.h
index 6355a36a3f81..b57118aaa679 100644
--- a/include/linux/cdx/cdx_bus.h
+++ b/include/linux/cdx/cdx_bus.h
@@ -12,6 +12,7 @@
 #include <linux/device.h>
 #include <linux/list.h>
 #include <linux/mod_devicetable.h>
+#include <linux/msi.h>
 
 #define MAX_CDX_DEV_RESOURCES	4
 #define CDX_CONTROLLER_ID_SHIFT 4
@@ -21,13 +22,25 @@
 struct cdx_controller;
 
 enum {
+	CDX_DEV_MSI_CONF,
 	CDX_DEV_BUS_MASTER_CONF,
 	CDX_DEV_RESET_CONF,
+	CDX_DEV_MSI_ENABLE,
+};
+
+struct cdx_msi_config {
+	u64 addr;
+	u32 data;
+	u16 msi_index;
 };
 
 struct cdx_device_config {
 	u8 type;
-	bool bus_master_enable;
+	union {
+		struct cdx_msi_config msi;
+		bool bus_master_enable;
+		bool msi_enable;
+	};
 };
 
 typedef int (*cdx_bus_enable_cb)(struct cdx_controller *cdx, u8 bus_num);
@@ -87,6 +100,7 @@ struct cdx_ops {
  * struct cdx_controller: CDX controller object
  * @dev: Linux device associated with the CDX controller.
  * @priv: private data
+ * @msi_domain: MSI domain
  * @id: Controller ID
  * @controller_registered: controller registered with bus
  * @ops: CDX controller ops
@@ -94,6 +108,7 @@ struct cdx_ops {
 struct cdx_controller {
 	struct device *dev;
 	void *priv;
+	struct irq_domain *msi_domain;
 	u32 id;
 	bool controller_registered;
 	struct cdx_ops *ops;
@@ -120,9 +135,13 @@ struct cdx_controller {
  * @req_id: Requestor ID associated with CDX device
  * @is_bus: Is this bus device
  * @enabled: is this bus enabled
+ * @msi_dev_id: MSI Device ID associated with CDX device
+ * @num_msi: Number of MSI's supported by the device
  * @driver_override: driver name to force a match; do not set directly,
  *                   because core frees it; use driver_set_override() to
  *                   set or clear it.
+ * @irqchip_lock: lock to synchronize irq/msi configuration
+ * @msi_write_pending: MSI write pending for this device
  */
 struct cdx_device {
 	struct device dev;
@@ -144,7 +163,11 @@ struct cdx_device {
 	u32 req_id;
 	bool is_bus;
 	bool enabled;
+	u32 msi_dev_id;
+	u32 num_msi;
 	const char *driver_override;
+	struct mutex irqchip_lock;
+	bool msi_write_pending;
 };
 
 #define to_cdx_device(_dev) \
@@ -237,4 +260,32 @@ int cdx_set_master(struct cdx_device *cdx_dev);
  */
 int cdx_clear_master(struct cdx_device *cdx_dev);
 
+#ifdef CONFIG_GENERIC_MSI_IRQ
+/**
+ * cdx_enable_msi - Enable MSI for the CDX device.
+ * @cdx_dev: device pointer
+ *
+ * Return: 0 for success, -errno on failure
+ */
+int cdx_enable_msi(struct cdx_device *cdx_dev);
+
+/**
+ * cdx_disable_msi - Disable MSI for the CDX device.
+ * @cdx_dev: device pointer
+ */
+void cdx_disable_msi(struct cdx_device *cdx_dev);
+
+#else /* CONFIG_GENERIC_MSI_IRQ */
+
+static inline int cdx_enable_msi(struct cdx_device *cdx_dev)
+{
+	return -ENODEV;
+}
+
+static inline void cdx_disable_msi(struct cdx_device *cdx_dev)
+{
+}
+
+#endif /* CONFIG_GENERIC_MSI_IRQ */
+
 #endif /* _CDX_BUS_H_ */