drm/i915/xehp: Add compute engine ABI

We're now ready to start exposing compute engines to userspace.

v2:
 - Move kerneldoc for other engine classes to a separate patch.  (Andi)

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Szymon Morek <szymon.morek@intel.com>
UMD (mesa): https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14395Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Tested-by: Jordan Justen <jordan.l.justen@intel.com>  # mesa anvil & iris
Link: https://patchwork.freedesktop.org/patch/msgid/20220428041926.1483683-4-matthew.d.roper@intel.com

drivers/gpu/drm/i915/gt/intel_engine_user.c

@@ -47,7 +47,7 @@ static const u8 uabi_classes[] = {
 	[COPY_ENGINE_CLASS] = I915_ENGINE_CLASS_COPY,
 	[VIDEO_DECODE_CLASS] = I915_ENGINE_CLASS_VIDEO,
 	[VIDEO_ENHANCEMENT_CLASS] = I915_ENGINE_CLASS_VIDEO_ENHANCE,
-	/* TODO: Add COMPUTE_CLASS mapping once ABI is available */
+	[COMPUTE_CLASS] = I915_ENGINE_CLASS_COMPUTE,
 };
 
 static int engine_cmp(void *priv, const struct list_head *A,

drivers/gpu/drm/i915/i915_drm_client.c

@@ -81,6 +81,7 @@ static const char * const uabi_class_names[] = {
 	[I915_ENGINE_CLASS_COPY] = "copy",
 	[I915_ENGINE_CLASS_VIDEO] = "video",
 	[I915_ENGINE_CLASS_VIDEO_ENHANCE] = "video-enhance",
+	[I915_ENGINE_CLASS_COMPUTE] = "compute",
 };
 
 static u64 busy_add(struct i915_gem_context *ctx, unsigned int class)

drivers/gpu/drm/i915/i915_drm_client.h

@@ -13,7 +13,7 @@
 
 #include "gt/intel_engine_types.h"
 
-#define I915_LAST_UABI_ENGINE_CLASS I915_ENGINE_CLASS_VIDEO_ENHANCE
+#define I915_LAST_UABI_ENGINE_CLASS I915_ENGINE_CLASS_COMPUTE
 
 struct drm_i915_private;
 

include/uapi/drm/i915_drm.h

@@ -203,6 +203,15 @@ enum drm_i915_gem_engine_class {
 	 */
 	I915_ENGINE_CLASS_VIDEO_ENHANCE	= 3,
 
+	/**
+	 * @I915_ENGINE_CLASS_COMPUTE:
+	 *
+	 * Compute engines support a subset of the instructions available
+	 * on render engines:  compute engines support Compute (GPGPU) and
+	 * programmable media workloads, but do not support the 3D pipeline.
+	 */
+	I915_ENGINE_CLASS_COMPUTE	= 4,
+
 	/* Values in this enum should be kept compact. */
 
 	/**