drm/i915/guc/slpc: Add waitboost functionality for SLPC

Add helper in RPS code for handling SLPC and non-SLPC paths.
When boost is requested in the SLPC path, we can ask GuC to ramp
up the frequency req by setting the minimum frequency to boost freq.
Reset freq back to the min softlimit when there are no more waiters.

v2: Schedule a worker thread which can boost freq from within
an interrupt context as well.

v3: No need to check against requested freq before scheduling boost
work (Ashutosh)

Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211102012608.8609-3-vinay.belgaumkar@intel.com

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
index 5e275f8dda8c..6f310c9d9765 100644
--- a/drivers/gpu/drm/i915/gt/intel_rps.c
+++ b/drivers/gpu/drm/i915/gt/intel_rps.c
@@ -936,8 +936,23 @@ void intel_rps_park(struct intel_rps *rps)
 	GT_TRACE(rps_to_gt(rps), "park:%x\n", rps->cur_freq);
 }
 
+void intel_rps_dec_waiters(struct intel_rps *rps)
+{
+	struct intel_guc_slpc *slpc;
+
+	if (rps_uses_slpc(rps)) {
+		slpc = rps_to_slpc(rps);
+
+		intel_guc_slpc_dec_waiters(slpc);
+	} else {
+		atomic_dec(&rps->num_waiters);
+	}
+}
+
 void intel_rps_boost(struct i915_request *rq)
 {
+	struct intel_guc_slpc *slpc;
+
 	if (i915_request_signaled(rq) || i915_request_has_waitboost(rq))
 		return;
 
@@ -945,6 +960,16 @@ void intel_rps_boost(struct i915_request *rq)
 	if (!test_and_set_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags)) {
 		struct intel_rps *rps = &READ_ONCE(rq->engine)->gt->rps;
 
+		if (rps_uses_slpc(rps)) {
+			slpc = rps_to_slpc(rps);
+
+			/* Return if old value is non zero */
+			if (!atomic_fetch_inc(&slpc->num_waiters))
+				schedule_work(&slpc->boost_work);
+
+			return;
+		}
+
 		if (atomic_fetch_inc(&rps->num_waiters))
 			return;