drm-uapi/v3d: extend interface for multiple semaphores support

Extends command submission ioctls to support multiple semaphores through
generic ioctl extension design. In this approach, a multisync extension
subclasses a generic ioctl extension struct (base) and enables more than
one wait and signal semaphores. Multisync extension also uses v3d_queue
to specify the wait_stage, i.e. which job should sync before start (wait
semaphores).

Signed-off-by: Melissa Wen <mwen@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13178>

include/drm-uapi/v3d_drm.h

@@ -58,6 +58,67 @@ extern "C" {
 						   struct drm_v3d_perfmon_get_values)
 
 #define DRM_V3D_SUBMIT_CL_FLUSH_CACHE             0x01
+#define DRM_V3D_SUBMIT_EXTENSION		  0x02
+
+/* struct drm_v3d_extension - ioctl extensions
+ *
+ * Linked-list of generic extensions where the id identify which struct is
+ * pointed by ext_data. Therefore, DRM_V3D_EXT_ID_* is used on id to identify
+ * the extension type.
+ */
+struct drm_v3d_extension {
+	__u64 next;
+	__u32 id;
+#define DRM_V3D_EXT_ID_MULTI_SYNC		0x01
+	__u32 flags; /* mbz */
+};
+
+/* struct drm_v3d_sem - wait/signal semaphore
+ *
+ * If binary semaphore, it only takes syncobj handle and ignores flags and
+ * point fields. Point is defined for timeline syncobj feature.
+ */
+struct drm_v3d_sem {
+	__u32 handle; /* syncobj */
+	/* rsv below, for future uses */
+	__u32 flags;
+	__u64 point;  /* for timeline sem support */
+	__u64 mbz[2]; /* must be zero, rsv */
+};
+
+/* Enum for each of the V3D queues. */
+enum v3d_queue {
+	V3D_BIN,
+	V3D_RENDER,
+	V3D_TFU,
+	V3D_CSD,
+	V3D_CACHE_CLEAN,
+};
+
+/**
+ * struct drm_v3d_multi_sync - ioctl extension to add support multiples
+ * syncobjs for commands submission.
+ *
+ * When an extension of DRM_V3D_EXT_ID_MULTI_SYNC id is defined, it points to
+ * this extension to define wait and signal dependencies, instead of single
+ * in/out sync entries on submitting commands. The field flags is used to
+ * determine the stage to set wait dependencies.
+ */
+struct drm_v3d_multi_sync {
+	struct drm_v3d_extension base;
+	/* Array of wait and signal semaphores */
+	__u64 in_syncs;
+	__u64 out_syncs;
+
+	/* Number of entries */
+	__u32 in_sync_count;
+	__u32 out_sync_count;
+
+	/* set the stage (v3d_queue) to sync */
+	__u32 wait_stage;
+
+	__u32 pad; /* mbz */
+};
 
 /**
  * struct drm_v3d_submit_cl - ioctl argument for submitting commands to the 3D
@@ -135,12 +196,16 @@ struct drm_v3d_submit_cl {
 	/* Number of BO handles passed in (size is that times 4). */
 	__u32 bo_handle_count;
 
+	/* DRM_V3D_SUBMIT_* properties */
 	__u32 flags;
 
 	/* ID of the perfmon to attach to this job. 0 means no perfmon. */
 	__u32 perfmon_id;
 
 	__u32 pad;
+
+	/* Pointer to an array of ioctl extensions*/
+	__u64 extensions;
 };
 
 /**
@@ -210,6 +275,7 @@ enum drm_v3d_param {
 	DRM_V3D_PARAM_SUPPORTS_CSD,
 	DRM_V3D_PARAM_SUPPORTS_CACHE_FLUSH,
 	DRM_V3D_PARAM_SUPPORTS_PERFMON,
+	DRM_V3D_PARAM_SUPPORTS_MULTISYNC_EXT,
 };
 
 struct drm_v3d_get_param {
@@ -248,6 +314,11 @@ struct drm_v3d_submit_tfu {
 	__u32 in_sync;
 	/* Sync object to signal when the TFU job is done. */
 	__u32 out_sync;
+
+	__u32 flags;
+
+	/* Pointer to an array of ioctl extensions*/
+	__u64 extensions;
 };
 
 /* Submits a compute shader for dispatch.  This job will block on any
@@ -276,6 +347,13 @@ struct drm_v3d_submit_csd {
 
 	/* ID of the perfmon to attach to this job. 0 means no perfmon. */
 	__u32 perfmon_id;
+
+	/* Pointer to an array of ioctl extensions*/
+	__u64 extensions;
+
+	__u32 flags;
+
+	__u32 pad;
 };
 
 enum {