[PATCH v2 2/7] drm/msm/hdmi: Handle msm_hdmi_power_on() errors during .atomic_pre_enable()

[Krzysztof Kozlowski]

Properly handle power up failures during .atomic_pre_enable() by
aborting the .atomic_pre_enable() to avoid accessing registers why
blocks did not bring up.  Otherwise this could lead to imprecise aborts
when accessing MMIO while entire power domain is off.

Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: ba3d7bf3a7ab ("drm/msm/hdmi: Convert PHY files according to new design")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/msm/hdmi/hdmi_bridge.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
index 157f19bd90b4..db85400e574e 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
@@ -13,14 +13,16 @@
 #include "msm_kms.h"
 #include "hdmi.h"
 
-static void msm_hdmi_power_on(struct drm_bridge *bridge)
+static int msm_hdmi_power_on(struct drm_bridge *bridge)
 {
 	struct drm_device *dev = bridge->dev;
 	struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
 	struct hdmi *hdmi = hdmi_bridge->hdmi;
 	int ret;
 
-	pm_runtime_resume_and_get(&hdmi->pdev->dev);
+	ret = pm_runtime_resume_and_get(&hdmi->pdev->dev);
+	if (ret)
+		return ret;
 
 	if (hdmi->extp_clk) {
 		DBG("pixclock: %lu", hdmi->pixclock);
@@ -29,9 +31,14 @@ static void msm_hdmi_power_on(struct drm_bridge *bridge)
 			DRM_DEV_ERROR(dev->dev, "failed to set extp clk rate: %d\n", ret);
 
 		ret = clk_prepare_enable(hdmi->extp_clk);
-		if (ret)
+		if (ret) {
 			DRM_DEV_ERROR(dev->dev, "failed to enable extp clk: %d\n", ret);
+			pm_runtime_put(&hdmi->pdev->dev);
+			return ret;
+		}
 	}
+
+	return 0;
 }
 
 static void power_off(struct drm_bridge *bridge)
@@ -287,13 +294,18 @@ static void msm_hdmi_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 
 	msm_hdmi_set_timings(hdmi, &crtc_state->adjusted_mode);
 
-	mutex_lock(&hdmi->state_mutex);
-	if (!hdmi->power_on) {
-		msm_hdmi_phy_resource_enable(phy);
-		msm_hdmi_power_on(bridge);
-		hdmi->power_on = true;
+	scoped_guard(mutex, &hdmi->state_mutex) {
+		if (!hdmi->power_on) {
+			if (msm_hdmi_phy_resource_enable(phy))
+				return;
+
+			if (msm_hdmi_power_on(bridge)) {
+				msm_hdmi_phy_resource_disable(phy);
+				return;
+			}
+			hdmi->power_on = true;
+		}
 	}
-	mutex_unlock(&hdmi->state_mutex);
 
 	if (connector->display_info.is_hdmi)
 		msm_hdmi_audio_update(hdmi);

-- 
2.53.0