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, 21 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
index ebc861b1a49e..b732cf99efcb 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.h
+++ b/drivers/gpu/drm/i915/gt/intel_context.h
@@ -73,6 +73,27 @@ static inline void __intel_context_pin(struct intel_context *ce)
 
 void intel_context_unpin(struct intel_context *ce);
 
+void intel_context_enter_engine(struct intel_context *ce);
+void intel_context_exit_engine(struct intel_context *ce);
+
+static inline void intel_context_enter(struct intel_context *ce)
+{
+	if (!ce->active_count++)
+		ce->ops->enter(ce);
+}
+
+static inline void intel_context_mark_active(struct intel_context *ce)
+{
+	++ce->active_count;
+}
+
+static inline void intel_context_exit(struct intel_context *ce)
+{
+	GEM_BUG_ON(!ce->active_count);
+	if (!--ce->active_count)
+		ce->ops->exit(ce);
+}
+
 static inline struct intel_context *intel_context_get(struct intel_context *ce)
 {
 	kref_get(&ce->ref);