[Intel-gfx] [PATCH 1/5] drm/i915: Add intel_display_power_{get, put} to request power for specific domains

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Add APIs to get/put power well references for specific purposes.

Also reorganize the internal i915_request power well handling to use the
reference count just like everyone else. This way all we need to do is
check the reference count and we know whether the power well needs to be
enabled of disabled.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_drv.h |  4 ++
 drivers/gpu/drm/i915/intel_pm.c  | 92 ++++++++++++++++++++++++++++++++++++----
 2 files changed, 87 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 774ebb6..2ecd3d2 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -763,6 +763,10 @@ extern void i915_remove_power_well(struct drm_device *dev);
 
 extern bool intel_display_power_enabled(struct drm_device *dev,
 					enum intel_display_power_domain domain);
+extern void intel_display_power_get(struct drm_device *dev,
+				    enum intel_display_power_domain domain);
+extern void intel_display_power_put(struct drm_device *dev,
+				    enum intel_display_power_domain domain);
 extern void intel_init_power_well(struct drm_device *dev);
 extern void intel_set_power_well(struct drm_device *dev, bool enable);
 extern void intel_enable_gt_powersave(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 8cffef4..4962303 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5333,6 +5333,69 @@ static void __intel_set_power_well(struct drm_device *dev, bool enable)
 	}
 }
 
+void intel_display_power_get(struct drm_device *dev,
+			     enum intel_display_power_domain domain)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct i915_power_well *power_well = &dev_priv->power_well;
+
+	if (!HAS_POWER_WELL(dev))
+		return;
+
+	switch (domain) {
+	case POWER_DOMAIN_PIPE_A:
+	case POWER_DOMAIN_TRANSCODER_EDP:
+		return;
+	case POWER_DOMAIN_PIPE_B:
+	case POWER_DOMAIN_PIPE_C:
+	case POWER_DOMAIN_PIPE_A_PANEL_FITTER:
+	case POWER_DOMAIN_PIPE_B_PANEL_FITTER:
+	case POWER_DOMAIN_PIPE_C_PANEL_FITTER:
+	case POWER_DOMAIN_TRANSCODER_A:
+	case POWER_DOMAIN_TRANSCODER_B:
+	case POWER_DOMAIN_TRANSCODER_C:
+		spin_lock_irq(&power_well->lock);
+		if (!power_well->count++)
+			__intel_set_power_well(power_well->device, true);
+		spin_unlock_irq(&power_well->lock);
+		return;
+	default:
+		BUG();
+	}
+}
+
+void intel_display_power_put(struct drm_device *dev,
+			     enum intel_display_power_domain domain)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct i915_power_well *power_well = &dev_priv->power_well;
+
+	if (!HAS_POWER_WELL(dev))
+		return;
+
+	switch (domain) {
+	case POWER_DOMAIN_PIPE_A:
+	case POWER_DOMAIN_TRANSCODER_EDP:
+		return;
+	case POWER_DOMAIN_PIPE_B:
+	case POWER_DOMAIN_PIPE_C:
+	case POWER_DOMAIN_PIPE_A_PANEL_FITTER:
+	case POWER_DOMAIN_PIPE_B_PANEL_FITTER:
+	case POWER_DOMAIN_PIPE_C_PANEL_FITTER:
+	case POWER_DOMAIN_TRANSCODER_A:
+	case POWER_DOMAIN_TRANSCODER_B:
+	case POWER_DOMAIN_TRANSCODER_C:
+		spin_lock_irq(&power_well->lock);
+		WARN_ON(!power_well->count);
+		if (!--power_well->count)
+			__intel_set_power_well(power_well->device, false);
+		spin_unlock_irq(&power_well->lock);
+		return;
+	default:
+		BUG();
+	}
+}
+
 static struct i915_power_well *hsw_pwr;
 
 /* Display audio driver power well request */
@@ -5342,8 +5405,7 @@ void i915_request_power_well(void)
 		return;
 
 	spin_lock_irq(&hsw_pwr->lock);
-	if (!hsw_pwr->count++ &&
-			!hsw_pwr->i915_request)
+	if (!hsw_pwr->count++)
 		__intel_set_power_well(hsw_pwr->device, true);
 	spin_unlock_irq(&hsw_pwr->lock);
 }
@@ -5357,8 +5419,7 @@ void i915_release_power_well(void)
 
 	spin_lock_irq(&hsw_pwr->lock);
 	WARN_ON(!hsw_pwr->count);
-	if (!--hsw_pwr->count &&
-		       !hsw_pwr->i915_request)
+	if (!--hsw_pwr->count)
 		__intel_set_power_well(hsw_pwr->device, false);
 	spin_unlock_irq(&hsw_pwr->lock);
 }
@@ -5394,15 +5455,28 @@ void intel_set_power_well(struct drm_device *dev, bool enable)
 		return;
 
 	spin_lock_irq(&power_well->lock);
+
+	/*
+	 * This function will only ever contribute one
+	 * to the power well reference count. i915_request
+	 * is what tracks whether we have or have not
+	 * added the one to the reference count.
+	 */
+	if (power_well->i915_request == enable)
+		goto out;
+
 	power_well->i915_request = enable;
 
-	/* only reject "disable" power well request */
-	if (power_well->count && !enable) {
-		spin_unlock_irq(&power_well->lock);
-		return;
+	if (enable) {
+		if (!power_well->count++)
+			__intel_set_power_well(dev, true);
+	} else {
+		WARN_ON(!power_well->count);
+		if (!--power_well->count)
+			__intel_set_power_well(dev, false);
 	}
 
-	__intel_set_power_well(dev, enable);
+ out:
 	spin_unlock_irq(&power_well->lock);
 }
 
-- 
1.8.1.5