[RFC v1 4/5] drm/netlink: Define multicast groups

[Aravind Iddamsetty <aravind.iddamsetty@xxxxxxxxxxxxxxx>]

Netlink subsystem supports event notifications to userspace. we define
two multicast groups for correctable and uncorrectable errors to which
userspace can subscribe and be notified when any of those errors happen.
The group names are local to the driver's genl netlink family.

Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@xxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/drm_netlink.c  |  2 ++
 include/drm/drm_netlink.h      | 10 ++++++++++
 include/uapi/drm/drm_netlink.h |  4 ++++
 3 files changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/drm_netlink.c b/drivers/gpu/drm/drm_netlink.c
index 843b2919b6ed..0c2dd62a9a8e 100644
--- a/drivers/gpu/drm/drm_netlink.c
+++ b/drivers/gpu/drm/drm_netlink.c
@@ -124,6 +124,8 @@ static void drm_genl_family_init(struct drm_device *dev)
 	dev->drm_genl_family.ops = drm_genl_ops;
 	dev->drm_genl_family.n_ops = ARRAY_SIZE(drm_genl_ops);
 	dev->drm_genl_family.maxattr = DRM_ATTR_MAX;
+	dev->drm_genl_family.mcgrps = drm_event_mcgrps;
+	dev->drm_genl_family.n_mcgrps = ARRAY_SIZE(drm_event_mcgrps);
 	dev->drm_genl_family.module = dev->dev->driver->owner;
 }
 
diff --git a/include/drm/drm_netlink.h b/include/drm/drm_netlink.h
index 60f7ee39ae0a..876f73087b18 100644
--- a/include/drm/drm_netlink.h
+++ b/include/drm/drm_netlink.h
@@ -28,6 +28,16 @@ static const struct nla_policy drm_attr_policy_read_one[DRM_ATTR_MAX + 1] = {
 	[DRM_RAS_ATTR_ERROR_ID] = { .type = NLA_U64 },
 };
 
+enum mcgrps_events {
+	DRM_GENL_MCAST_CORR_ERR,
+	DRM_GENL_MCAST_UNCORR_ERR,
+};
+
+static const struct genl_multicast_group drm_event_mcgrps[] = {
+	[DRM_GENL_MCAST_CORR_ERR] = { .name = DRM_GENL_MCAST_GROUP_NAME_CORR_ERR, },
+	[DRM_GENL_MCAST_UNCORR_ERR] = { .name = DRM_GENL_MCAST_GROUP_NAME_UNCORR_ERR, },
+};
+
 int drm_genl_register(struct drm_device *dev);
 void drm_genl_exit(void);
 int drm_genl_send(struct sk_buff *msg, struct genl_info *info, void *usrhdr);
diff --git a/include/uapi/drm/drm_netlink.h b/include/uapi/drm/drm_netlink.h
index aab42147a20e..c7a0ce5b4624 100644
--- a/include/uapi/drm/drm_netlink.h
+++ b/include/uapi/drm/drm_netlink.h
@@ -26,6 +26,8 @@
 #define _DRM_NETLINK_H_
 
 #define DRM_GENL_VERSION 1
+#define DRM_GENL_MCAST_GROUP_NAME_CORR_ERR	"drm_corr_err"
+#define DRM_GENL_MCAST_GROUP_NAME_UNCORR_ERR	"drm_uncorr_err"
 
 #if defined(__cplusplus)
 extern "C" {
@@ -43,6 +45,8 @@ enum drm_genl_error_cmds {
 	DRM_RAS_CMD_READ_ONE,
 	/** @DRM_RAS_CMD_READ_ALL: Command to get counters of all errors */
 	DRM_RAS_CMD_READ_ALL,
+	/** @DRM_RAS_CMD_ERROR_EVENT: Command sent as part of multicast event */
+	DRM_RAS_CMD_ERROR_EVENT,
 
 	__DRM_CMD_MAX,
 	DRM_CMD_MAX = __DRM_CMD_MAX - 1,
-- 
2.25.1