[Intel-gfx] [PATCH] drm/i915: New vfunc prepare_request

[Oscar Mateo]

This will be more useful later to support platforms that need to emit
HW commands at the beginning of every request (more general than emitting
things at the beginning of every batchbuffer, which is already covered by
emit_bb_start).

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Signed-off-by: Oscar Mateo <oscar.mateo at intel.com>
---
 drivers/gpu/drm/i915/intel_lrc.c        | 17 ++++++++++++-----
 drivers/gpu/drm/i915/intel_ringbuffer.h |  1 +
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 9488578..a5c055a 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -687,6 +687,15 @@ static bool insert_request(struct i915_priotree *pt, struct rb_root *root)
 	return first;
 }
 
+static int execlists_prepare_request(struct drm_i915_gem_request *request)
+{
+	u32 *cs = intel_ring_begin(request, 0);
+	if (IS_ERR(cs))
+		return PTR_ERR(cs);
+
+	return 0;
+}
+
 static void execlists_submit_request(struct drm_i915_gem_request *request)
 {
 	struct intel_engine_cs *engine = request->engine;
@@ -879,7 +888,6 @@ static int execlists_request_alloc(struct drm_i915_gem_request *request)
 {
 	struct intel_engine_cs *engine = request->engine;
 	struct intel_context *ce = &request->ctx->engine[engine->id];
-	u32 *cs;
 	int ret;
 
 	GEM_BUG_ON(!ce->pin_count);
@@ -904,11 +912,9 @@ static int execlists_request_alloc(struct drm_i915_gem_request *request)
 			goto err;
 	}
 
-	cs = intel_ring_begin(request, 0);
-	if (IS_ERR(cs)) {
-		ret = PTR_ERR(cs);
+	ret = engine->prepare_request(request);
+	if (ret)
 		goto err_unreserve;
-	}
 
 	if (!ce->initialised) {
 		ret = engine->init_context(request);
@@ -1650,6 +1656,7 @@ void intel_logical_ring_cleanup(struct intel_engine_cs *engine)
 
 static void execlists_set_default_submission(struct intel_engine_cs *engine)
 {
+	engine->prepare_request = execlists_prepare_request;
 	engine->submit_request = execlists_submit_request;
 	engine->schedule = execlists_schedule;
 	engine->irq_tasklet.func = intel_lrc_irq_handler;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index d901831..67de978 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -303,6 +303,7 @@ struct intel_engine_cs {
 	void		(*emit_breadcrumb)(struct drm_i915_gem_request *req,
 					   u32 *cs);
 	int		emit_breadcrumb_sz;
+	int             (*prepare_request)(struct drm_i915_gem_request *req);
 
 	/* Pass the request to the hardware queue (e.g. directly into
 	 * the legacy ringbuffer or to the end of an execlist).
-- 
1.9.1