[Intel-gfx] [RFC 2/3] drm/i915: Add a routine to map from UABI id to engine

[Chris Wilson]

We have to mix a static UABI engine id with the potential for a varying
hw_id and layout, and so we need a way to map from the userspace id for
an engine to our internal pointers.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_engine_cs.c  | 17 +++++++++++++++++
 drivers/gpu/drm/i915/intel_ringbuffer.h |  3 +++
 2 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 0f8b3312dad8..8a197f826d38 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1125,6 +1125,23 @@ void intel_engines_cleanup(struct drm_i915_private *i915)
 		engine->cleanup(engine);
 }
 
+struct intel_engine_cs *
+intel_engine_lookup(struct drm_i915_private *i915, u32 uabi_id)
+{
+	static const enum intel_engine_id uabi_map[] = {
+		[I915_EXEC_DEFAULT]	= RCS,
+		[I915_EXEC_RENDER]	= RCS,
+		[I915_EXEC_BLT]		= BCS,
+		[I915_EXEC_BSD]		= VCS,
+		[I915_EXEC_VEBOX]	= VECS,
+	};
+
+	if (uabi_id >= ARRAY_SIZE(uabi_map))
+		return NULL;
+
+	return i915->engine[uabi_map[uabi_id]];
+}
+
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftests/mock_engine.c"
 #endif
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 53880389e6c9..7f8366da5a4c 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -671,6 +671,9 @@ static inline u32 *gen8_emit_pipe_control(u32 *batch, u32 flags, u32 offset)
 	return batch + 6;
 }
 
+struct intel_engine_cs *
+intel_engine_lookup(struct drm_i915_private *i915, u32 uabi_id);
+
 bool intel_engine_is_idle(struct intel_engine_cs *engine);
 bool intel_engines_are_idle(struct drm_i915_private *dev_priv);
 
-- 
2.11.0