[Intel-gfx] [PATCH 2/4] drm/i915: Introduce SAGV mutex.

[Rodrigo Vivi]

Now that we are spreading the places we can manipulate
sagv status let's protect it.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h | 15 +++++++++------
 drivers/gpu/drm/i915/intel_pm.c | 41 ++++++++++++++++++++++++++---------------
 2 files changed, 35 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 82a106b1bdbc..4c5174ceab96 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2122,12 +2122,15 @@ struct drm_i915_private {
 	struct i915_suspend_saved_registers regfile;
 	struct vlv_s0ix_state vlv_s0ix_state;
 
-	enum {
-		I915_SAGV_UNKNOWN = 0,
-		I915_SAGV_DISABLED,
-		I915_SAGV_ENABLED,
-		I915_SAGV_NOT_CONTROLLED
-	} sagv_status;
+	struct {
+		enum {
+			I915_SAGV_UNKNOWN = 0,
+			I915_SAGV_DISABLED,
+			I915_SAGV_ENABLED,
+			I915_SAGV_NOT_CONTROLLED
+		} status;
+		struct mutex lock;
+	} sagv;
 
 	struct {
 		/*
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 2b6419b7bdd1..e1ec9c2fd08a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3584,15 +3584,19 @@ static bool skl_needs_memory_bw_wa(struct intel_atomic_state *state)
 static bool
 intel_has_sagv(struct drm_i915_private *dev_priv)
 {
+	bool ret = false;
+
 	if (IS_KABYLAKE(dev_priv) || IS_COFFEELAKE(dev_priv) ||
 	    IS_CANNONLAKE(dev_priv))
 		return true;
 
+	mutex_lock(&dev_priv->sagv.lock);
 	if (IS_SKYLAKE(dev_priv) &&
-	    dev_priv->sagv_status != I915_SAGV_NOT_CONTROLLED)
-		return true;
+	    dev_priv->sagv.status != I915_SAGV_NOT_CONTROLLED)
+		ret = true;
+	mutex_unlock(&dev_priv->sagv.lock);
 
-	return false;
+	return ret;
 }
 
 /*
@@ -3613,8 +3617,9 @@ void intel_enable_sagv(struct drm_i915_private *dev_priv)
 	if (!intel_has_sagv(dev_priv))
 		return;
 
-	if (dev_priv->sagv_status == I915_SAGV_ENABLED)
-		return;
+	mutex_lock(&dev_priv->sagv.lock);
+	if (dev_priv->sagv.status == I915_SAGV_ENABLED)
+		goto out;
 
 	DRM_DEBUG_KMS("Enabling the SAGV\n");
 	mutex_lock(&dev_priv->pcu_lock);
@@ -3631,14 +3636,16 @@ void intel_enable_sagv(struct drm_i915_private *dev_priv)
 	 */
 	if (IS_SKYLAKE(dev_priv) && ret == -ENXIO) {
 		DRM_DEBUG_DRIVER("No SAGV found on system, ignoring\n");
-		dev_priv->sagv_status = I915_SAGV_NOT_CONTROLLED;
-		return;
+		dev_priv->sagv.status = I915_SAGV_NOT_CONTROLLED;
+		goto out;
 	} else if (ret < 0) {
 		DRM_ERROR("Failed to enable the SAGV (%d)\n", ret);
-		return;
+		goto out;
 	}
 
-	dev_priv->sagv_status = I915_SAGV_ENABLED;
+	dev_priv->sagv.status = I915_SAGV_ENABLED;
+out:
+	mutex_unlock(&dev_priv->sagv.lock);
 }
 
 void intel_disable_sagv(struct drm_i915_private *dev_priv)
@@ -3648,8 +3655,9 @@ void intel_disable_sagv(struct drm_i915_private *dev_priv)
 	if (!intel_has_sagv(dev_priv))
 		return;
 
-	if (dev_priv->sagv_status == I915_SAGV_DISABLED)
-		return;
+	mutex_lock(&dev_priv->sagv.lock);
+	if (dev_priv->sagv.status == I915_SAGV_DISABLED)
+		goto out;
 
 	DRM_DEBUG_KMS("Disabling the SAGV\n");
 	mutex_lock(&dev_priv->pcu_lock);
@@ -3667,14 +3675,16 @@ void intel_disable_sagv(struct drm_i915_private *dev_priv)
 	 */
 	if (IS_SKYLAKE(dev_priv) && ret == -ENXIO) {
 		DRM_DEBUG_DRIVER("No SAGV found on system, ignoring\n");
-		dev_priv->sagv_status = I915_SAGV_NOT_CONTROLLED;
-		return;
+		dev_priv->sagv.status = I915_SAGV_NOT_CONTROLLED;
+		goto out;
 	} else if (ret < 0) {
 		DRM_ERROR("Failed to disable the SAGV (%d)\n", ret);
-		return;
+		goto out;
 	}
 
-	dev_priv->sagv_status = I915_SAGV_DISABLED;
+	dev_priv->sagv.status = I915_SAGV_DISABLED;
+out:
+	mutex_unlock(&dev_priv->sagv.lock);
 }
 
 bool intel_can_enable_sagv(struct drm_atomic_state *state)
@@ -9046,6 +9056,7 @@ void intel_init_clock_gating_hooks(struct drm_i915_private *dev_priv)
 void intel_init_pm(struct drm_i915_private *dev_priv)
 {
 	intel_fbc_init(dev_priv);
+	mutex_init(&dev_priv->sagv.lock);
 
 	/* For cxsr */
 	if (IS_PINEVIEW(dev_priv))
-- 
2.13.6