[PATCH] drm/i915: Add functions to force psr exit

[Rodrigo Vivi <rodrigo.vivi@gmail.com>]

PSR tracking engine in HSW doesn't detect automagically some directly copy area
operations through scanout so we will have to kick it manually and
reschedule it to come back to normal operation as soon as possible.

v2: Before PSR Hook. Don't force it when busy yet.
v3/v4: Solved small conflict.
v5: setup once function was already added on previous commit.
v6: Use POSTING_READ to make sure the mutex works as a write barrier as
    suggested by Chris Wilson

CC: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Shobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
---
 drivers/gpu/drm/i915/i915_reg.h  |  1 +
 drivers/gpu/drm/i915/intel_dp.c  | 48 ++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h |  3 +++
 3 files changed, 52 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 3bca337..dc10345 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1840,6 +1840,7 @@
 #define   EDP_PSR_PERF_CNT_MASK		0xffffff
 
 #define EDP_PSR_DEBUG_CTL		0x64860
+#define   EDP_PSR_DEBUG_FORCE_EXIT	(3<<30)
 #define   EDP_PSR_DEBUG_MASK_LPSP	(1<<27)
 #define   EDP_PSR_DEBUG_MASK_MEMUP	(1<<26)
 #define   EDP_PSR_DEBUG_MASK_HPD	(1<<25)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 3c9473c..47e1676 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1393,6 +1393,50 @@ bool intel_edp_is_psr_enabled(struct drm_device *dev)
 	return I915_READ(EDP_PSR_CTL) & EDP_PSR_ENABLE;
 }
 
+static void intel_edp_psr_delayed_normal_work(struct work_struct *__work)
+{
+	struct intel_dp *intel_dp = container_of(to_delayed_work(__work),
+						 struct intel_dp,
+						 edp_psr_delayed_normal_work);
+	struct drm_device *dev = intel_dp_to_dev(intel_dp);
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	mutex_lock(&intel_dp->psr_exit_mutex);
+	I915_WRITE(EDP_PSR_DEBUG_CTL, I915_READ(EDP_PSR_DEBUG_CTL) &
+		   ~EDP_PSR_DEBUG_FORCE_EXIT);
+	POSTING_READ(EDP_PSR_DEBUG_CTL);
+	mutex_unlock(&intel_dp->psr_exit_mutex);
+}
+
+void intel_edp_psr_force_exit(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_encoder *encoder;
+	struct intel_dp *intel_dp = NULL;
+
+	if (!intel_edp_is_psr_enabled(dev))
+		return;
+
+	list_for_each_entry(encoder, &dev->mode_config.encoder_list, base.head)
+		if (encoder->type == INTEL_OUTPUT_EDP)
+			intel_dp = enc_to_intel_dp(&encoder->base);
+
+	if (!intel_dp)
+		return;
+
+	if (WARN_ON(!intel_dp->psr_setup_done))
+		return;
+
+	mutex_lock(&intel_dp->psr_exit_mutex);
+	I915_WRITE(EDP_PSR_DEBUG_CTL, I915_READ(EDP_PSR_DEBUG_CTL) |
+		   EDP_PSR_DEBUG_FORCE_EXIT);
+	POSTING_READ(EDP_PSR_DEBUG_CTL);
+	mutex_unlock(&intel_dp->psr_exit_mutex);
+
+	schedule_delayed_work(&intel_dp->edp_psr_delayed_normal_work,
+			      msecs_to_jiffies(100));
+}
+
 static void intel_edp_psr_write_vsc(struct intel_dp *intel_dp,
 				    struct edp_vsc_psr *vsc_psr)
 {
@@ -1443,6 +1487,10 @@ static void intel_edp_psr_setup(struct intel_dp *intel_dp)
 	I915_WRITE(EDP_PSR_DEBUG_CTL, EDP_PSR_DEBUG_MASK_MEMUP |
 		   EDP_PSR_DEBUG_MASK_HPD);
 
+	INIT_DELAYED_WORK(&intel_dp->edp_psr_delayed_normal_work,
+			  intel_edp_psr_delayed_normal_work);
+	mutex_init(&intel_dp->psr_exit_mutex);
+
 	intel_dp->psr_setup_done = true;
 }
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 0f52362..e47f3f3 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -499,6 +499,8 @@ struct intel_dp {
 	int backlight_off_delay;
 	struct delayed_work panel_vdd_work;
 	bool want_panel_vdd;
+	struct delayed_work edp_psr_delayed_normal_work;
+	struct mutex psr_exit_mutex;
 	bool psr_setup_done;
 	struct intel_connector *attached_connector;
 };
@@ -839,5 +841,6 @@ extern void intel_edp_psr_enable(struct intel_dp *intel_dp);
 extern void intel_edp_psr_disable(struct intel_dp *intel_dp);
 extern void intel_edp_psr_update(struct drm_device *dev);
 extern bool intel_edp_is_psr_enabled(struct drm_device *dev);
+extern void intel_edp_psr_force_exit(struct drm_device *dev);
 
 #endif /* __INTEL_DRV_H__ */
-- 
1.8.1.4