[Intel-gfx] [PATCH v2] drm/i915/display: Introduce new intel_psr_pause/resume function

[Gwan-gyeong Mun]

This introduces the following function that can exit and activate a psr
source when intel_psr is already enabled.

- intel_psr_pause(): Pause current PSR. It deactivates current psr state.
- intel_psr_resume(): Resume paused PSR. It activates paused psr state.

v2: Address Jose's review comment.
  - Remove unneeded changes around the intel_psr_enable().
  - Add intel_psr_post_exit() which processes waiting until PSR is idle
    and WA for SelectiveFetch.

Cc: José Roberto de Souza <jose.souza at intel.com>
Cc: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun at intel.com>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
 .../drm/i915/display/intel_display_types.h    |  1 +
 drivers/gpu/drm/i915/display/intel_psr.c      | 84 ++++++++++++++++---
 drivers/gpu/drm/i915/display/intel_psr.h      |  2 +
 3 files changed, 76 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index b8d1f702d808..ee7cbdd7db87 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1482,6 +1482,7 @@ struct intel_psr {
 	bool sink_support;
 	bool source_support;
 	bool enabled;
+	bool paused;
 	enum pipe pipe;
 	enum transcoder transcoder;
 	bool active;
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 000e1ffe8c05..4ff71e529cd3 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -1113,6 +1113,7 @@ static void intel_psr_enable_locked(struct intel_dp *intel_dp,
 	intel_psr_enable_sink(intel_dp);
 	intel_psr_enable_source(intel_dp);
 	intel_dp->psr.enabled = true;
+	intel_dp->psr.paused = false;
 
 	intel_psr_activate(intel_dp);
 }
@@ -1182,22 +1183,12 @@ static void intel_psr_exit(struct intel_dp *intel_dp)
 	intel_dp->psr.active = false;
 }
 
-static void intel_psr_disable_locked(struct intel_dp *intel_dp)
+static void intel_psr_post_exit(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
 	i915_reg_t psr_status;
 	u32 psr_status_mask;
 
-	lockdep_assert_held(&intel_dp->psr.lock);
-
-	if (!intel_dp->psr.enabled)
-		return;
-
-	drm_dbg_kms(&dev_priv->drm, "Disabling PSR%s\n",
-		    intel_dp->psr.psr2_enabled ? "2" : "1");
-
-	intel_psr_exit(intel_dp);
-
 	if (intel_dp->psr.psr2_enabled) {
 		psr_status = EDP_PSR2_STATUS(intel_dp->psr.transcoder);
 		psr_status_mask = EDP_PSR2_STATUS_STATE_MASK;
@@ -1217,6 +1208,22 @@ static void intel_psr_disable_locked(struct intel_dp *intel_dp)
 	     IS_RKL_REVID(dev_priv, RKL_REVID_A0, RKL_REVID_A0)))
 		intel_de_rmw(dev_priv, CHICKEN_PAR1_1,
 			     DIS_RAM_BYPASS_PSR2_MAN_TRACK, 0);
+}
+
+static void intel_psr_disable_locked(struct intel_dp *intel_dp)
+{
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+
+	lockdep_assert_held(&intel_dp->psr.lock);
+
+	if (!intel_dp->psr.enabled)
+		return;
+
+	drm_dbg_kms(&dev_priv->drm, "Disabling PSR%s\n",
+		    intel_dp->psr.psr2_enabled ? "2" : "1");
+
+	intel_psr_exit(intel_dp);
+	intel_psr_post_exit(intel_dp);
 
 	/* Disable PSR on Sink */
 	drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG, 0);
@@ -1254,6 +1261,61 @@ void intel_psr_disable(struct intel_dp *intel_dp,
 	cancel_delayed_work_sync(&intel_dp->psr.dc3co_work);
 }
 
+/**
+ * intel_psr_pause - Pause PSR
+ * @intel_dp: Intel DP
+ *
+ * This function need to be called after enabling psr.
+ */
+void intel_psr_pause(struct intel_dp *intel_dp)
+{
+	struct intel_psr *psr = &intel_dp->psr;
+
+	if (!CAN_PSR(intel_dp))
+		return;
+
+	mutex_lock(&psr->lock);
+
+	if (!psr->active) {
+		mutex_unlock(&psr->lock);
+		return;
+	}
+
+	intel_psr_exit(intel_dp);
+	intel_psr_post_exit(intel_dp);
+	psr->paused = true;
+
+	mutex_unlock(&psr->lock);
+
+	cancel_work_sync(&psr->work);
+	cancel_delayed_work_sync(&psr->dc3co_work);
+}
+
+/**
+ * intel_psr_resume - Resume PSR
+ * @intel_dp: Intel DP
+ *
+ * This function need to be called after pausing psr.
+ */
+void intel_psr_resume(struct intel_dp *intel_dp)
+{
+	struct intel_psr *psr = &intel_dp->psr;
+
+	if (!CAN_PSR(intel_dp))
+		return;
+
+	mutex_lock(&psr->lock);
+
+	if (!psr->paused)
+		goto unlock;
+
+	psr->paused = false;
+	intel_psr_activate(intel_dp);
+
+unlock:
+	mutex_unlock(&psr->lock);
+}
+
 static void psr_force_hw_tracking_exit(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
diff --git a/drivers/gpu/drm/i915/display/intel_psr.h b/drivers/gpu/drm/i915/display/intel_psr.h
index e3db85e97f4c..641521b101c8 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.h
+++ b/drivers/gpu/drm/i915/display/intel_psr.h
@@ -51,5 +51,7 @@ void intel_psr2_program_plane_sel_fetch(struct intel_plane *plane,
 					const struct intel_crtc_state *crtc_state,
 					const struct intel_plane_state *plane_state,
 					int color_plane);
+void intel_psr_pause(struct intel_dp *intel_dp);
+void intel_psr_resume(struct intel_dp *intel_dp);
 
 #endif /* __INTEL_PSR_H__ */
-- 
2.31.1