drm/i915: Introduce context->enter() and context->exit()

We wish to start segregating the power management into different control
domains, both with respect to the hardware and the user interface. The
first step is that at the lowest level flow of requests, we want to
process a context event (and not a global GEM operation). In this patch,
we introduce the context callbacks that in future patches will be
redirected to per-engine interfaces leading to global operations as
required.

The intent is that this will be guarded by the timeline->mutex, except
that retiring has not quite finished transitioning over from being
guarded by struct_mutex. So at the moment it is protected by
struct_mutex with a reminded to switch.

v2: Rename default handlers to intel_context_enter_engine.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190424200717.1686-3-chris@chris-wilson.co.uk

1 files changed, 4 insertions, 18 deletions

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 64ca8b3ea12f..9a2665ee012a 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -131,19 +131,6 @@ i915_request_remove_from_client(struct i915_request *request)
 	spin_unlock(&file_priv->mm.lock);
 }
 
-static void reserve_gt(struct drm_i915_private *i915)
-{
-	if (!i915->gt.active_requests++)
-		i915_gem_unpark(i915);
-}
-
-static void unreserve_gt(struct drm_i915_private *i915)
-{
-	GEM_BUG_ON(!i915->gt.active_requests);
-	if (!--i915->gt.active_requests)
-		i915_gem_park(i915);
-}
-
 static void advance_ring(struct i915_request *request)
 {
 	struct intel_ring *ring = request->ring;
@@ -301,11 +288,10 @@ static void i915_request_retire(struct i915_request *request)
 
 	i915_request_remove_from_client(request);
 
-	intel_context_unpin(request->hw_context);
-
 	__retire_engine_upto(request->engine, request);
 
-	unreserve_gt(request->i915);
+	intel_context_exit(request->hw_context);
+	intel_context_unpin(request->hw_context);
 
 	i915_sched_node_fini(&request->sched);
 	i915_request_put(request);
@@ -659,8 +645,8 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx)
 	if (IS_ERR(ce))
 		return ERR_CAST(ce);
 
-	reserve_gt(i915);
 	mutex_lock(&ce->ring->timeline->mutex);
+	intel_context_enter(ce);
 
 	/* Move our oldest request to the slab-cache (if not in use!) */
 	rq = list_first_entry(&ce->ring->request_list, typeof(*rq), ring_link);
@@ -791,8 +777,8 @@ err_unwind:
 err_free:
 	kmem_cache_free(global.slab_requests, rq);
 err_unreserve:
+	intel_context_exit(ce);
 	mutex_unlock(&ce->ring->timeline->mutex);
-	unreserve_gt(i915);
 	intel_context_unpin(ce);
 	return ERR_PTR(ret);
 }