Re: [PATCH v5 16/36] drm/bridge: analogix_dp: Check dpcd write/read status

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On Saturday 10 March 2018 03:53 AM, Enric Balletbo i Serra wrote:

From: Lin Huang <hl@xxxxxxxxxxxxxx>

We need to check the dpcd write/read return value to see whether the
write/read was successful



Reviewed-by: Archit Taneja <architt@xxxxxxxxxxxxxx>

Thanks,
Archit


Cc: Kristian H. Kristensen <hoegsberg@xxxxxxxxxxxx>
Signed-off-by: Lin Huang <hl@xxxxxxxxxxxxxx>
Signed-off-by: zain wang <wzz@xxxxxxxxxxxxxx>
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxxxxx>
Reviewed-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---

  drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 169 ++++++++++++++++-----
  1 file changed, 127 insertions(+), 42 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 1eed35f9eb8d..be6eddd0d0a7 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -160,80 +160,137 @@ int analogix_dp_disable_psr(struct analogix_dp_device *dp)
  }
  EXPORT_SYMBOL_GPL(analogix_dp_disable_psr);
-static bool analogix_dp_detect_sink_psr(struct analogix_dp_device *dp) 
+static int analogix_dp_detect_sink_psr(struct analogix_dp_device *dp)
  {
  	unsigned char psr_version;
+	int ret;
+
+	ret = drm_dp_dpcd_readb(&dp->aux, DP_PSR_SUPPORT, &psr_version);
+	if (ret != 1) {
+		dev_err(dp->dev, "failed to get PSR version, disable it\n");
+		return ret;
+	}
- drm_dp_dpcd_readb(&dp->aux, DP_PSR_SUPPORT, &psr_version); 
  	dev_dbg(dp->dev, "Panel PSR version : %x\n", psr_version);
- return (psr_version & DP_PSR_IS_SUPPORTED) ? true : false; 
+	dp->psr_enable = (psr_version & DP_PSR_IS_SUPPORTED) ? true : false;
+
+	return 0;
  }
-static void analogix_dp_enable_sink_psr(struct analogix_dp_device *dp) 
+static int analogix_dp_enable_sink_psr(struct analogix_dp_device *dp)
  {
  	unsigned char psr_en;
+	int ret;
/* Disable psr function */ 
-	drm_dp_dpcd_readb(&dp->aux, DP_PSR_EN_CFG, &psr_en);
+	ret = drm_dp_dpcd_readb(&dp->aux, DP_PSR_EN_CFG, &psr_en);
+	if (ret != 1) {
+		dev_err(dp->dev, "failed to get psr config\n");
+		goto end;
+	}
+
  	psr_en &= ~DP_PSR_ENABLE;
-	drm_dp_dpcd_writeb(&dp->aux, DP_PSR_EN_CFG, psr_en);
+	ret = drm_dp_dpcd_writeb(&dp->aux, DP_PSR_EN_CFG, psr_en);
+	if (ret != 1) {
+		dev_err(dp->dev, "failed to disable panel psr\n");
+		goto end;
+	}
/* Main-Link transmitter remains active during PSR active states */ 
  	psr_en = DP_PSR_MAIN_LINK_ACTIVE | DP_PSR_CRC_VERIFICATION;
-	drm_dp_dpcd_writeb(&dp->aux, DP_PSR_EN_CFG, psr_en);
+	ret = drm_dp_dpcd_writeb(&dp->aux, DP_PSR_EN_CFG, psr_en);
+	if (ret != 1) {
+		dev_err(dp->dev, "failed to set panel psr\n");
+		goto end;
+	}
/* Enable psr function */ 
  	psr_en = DP_PSR_ENABLE | DP_PSR_MAIN_LINK_ACTIVE |
  		 DP_PSR_CRC_VERIFICATION;
-	drm_dp_dpcd_writeb(&dp->aux, DP_PSR_EN_CFG, psr_en);
+	ret = drm_dp_dpcd_writeb(&dp->aux, DP_PSR_EN_CFG, psr_en);
+	if (ret != 1) {
+		dev_err(dp->dev, "failed to set panel psr\n");
+		goto end;
+	}
analogix_dp_enable_psr_crc(dp); 
+
+	return 0;
+end:
+	dev_err(dp->dev, "enable psr fail, force to disable psr\n");
+	dp->psr_enable = false;
+
+	return ret;
  }
-static void 
+static int
  analogix_dp_enable_rx_to_enhanced_mode(struct analogix_dp_device *dp,
  				       bool enable)
  {
  	u8 data;
+	int ret;
- drm_dp_dpcd_readb(&dp->aux, DP_LANE_COUNT_SET, &data); 
+	ret = drm_dp_dpcd_readb(&dp->aux, DP_LANE_COUNT_SET, &data);
+	if (ret != 1)
+		return ret;
if (enable) 
-		drm_dp_dpcd_writeb(&dp->aux, DP_LANE_COUNT_SET,
-				   DP_LANE_COUNT_ENHANCED_FRAME_EN |
-					DPCD_LANE_COUNT_SET(data));
+		ret = drm_dp_dpcd_writeb(&dp->aux, DP_LANE_COUNT_SET,
+					 DP_LANE_COUNT_ENHANCED_FRAME_EN |
+					 DPCD_LANE_COUNT_SET(data));
  	else
-		drm_dp_dpcd_writeb(&dp->aux, DP_LANE_COUNT_SET,
-				   DPCD_LANE_COUNT_SET(data));
+		ret = drm_dp_dpcd_writeb(&dp->aux, DP_LANE_COUNT_SET,
+					 DPCD_LANE_COUNT_SET(data));
+
+	return ret < 0 ? ret : 0;
  }
-static int analogix_dp_is_enhanced_mode_available(struct analogix_dp_device *dp) 
+static int analogix_dp_is_enhanced_mode_available(struct analogix_dp_device *dp,
+						  u8 *enhanced_mode_support)
  {
  	u8 data;
-	int retval;
+	int ret;
- drm_dp_dpcd_readb(&dp->aux, DP_MAX_LANE_COUNT, &data); 
-	retval = DPCD_ENHANCED_FRAME_CAP(data);
+	ret = drm_dp_dpcd_readb(&dp->aux, DP_MAX_LANE_COUNT, &data);
+	if (ret != 1) {
+		*enhanced_mode_support = 0;
+		return ret;
+	}
- return retval; 
+	*enhanced_mode_support = DPCD_ENHANCED_FRAME_CAP(data);
+
+	return 0;
  }
-static void analogix_dp_set_enhanced_mode(struct analogix_dp_device *dp) 
+static int analogix_dp_set_enhanced_mode(struct analogix_dp_device *dp)
  {
  	u8 data;
+	int ret;
+
+	ret = analogix_dp_is_enhanced_mode_available(dp, &data);
+	if (ret < 0)
+		return ret;
+
+	ret = analogix_dp_enable_rx_to_enhanced_mode(dp, data);
+	if (ret < 0)
+		return ret;
- data = analogix_dp_is_enhanced_mode_available(dp); 
-	analogix_dp_enable_rx_to_enhanced_mode(dp, data);
  	analogix_dp_enable_enhanced_mode(dp, data);
+
+	return 0;
  }
-static void analogix_dp_training_pattern_dis(struct analogix_dp_device *dp) 
+static int analogix_dp_training_pattern_dis(struct analogix_dp_device *dp)
  {
+	int ret;
+
  	analogix_dp_set_training_pattern(dp, DP_NONE);
- drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET, 
-			   DP_TRAINING_PATTERN_DISABLE);
+	ret = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
+				 DP_TRAINING_PATTERN_DISABLE);
+
+	return ret < 0 ? ret : 0;
  }
static void 
@@ -282,7 +339,11 @@ static int analogix_dp_link_start(struct analogix_dp_device *dp)
  	if (retval < 0)
  		return retval;
  	/* set enhanced mode if available */
-	analogix_dp_set_enhanced_mode(dp);
+	retval = analogix_dp_set_enhanced_mode(dp);
+	if (retval < 0) {
+		dev_err(dp->dev, "failed to set enhance mode\n");
+		return retval;
+	}
/* Set TX pre-emphasis to minimum */ 
  	for (lane = 0; lane < lane_count; lane++)
@@ -567,10 +628,11 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
if (!analogix_dp_channel_eq_ok(link_status, link_align, lane_count)) { 
  		/* traing pattern Set to Normal */
-		analogix_dp_training_pattern_dis(dp);
+		retval = analogix_dp_training_pattern_dis(dp);
+		if (retval < 0)
+			return retval;
dev_info(dp->dev, "Link Training success!\n"); 
-
  		analogix_dp_get_link_bandwidth(dp, &reg);
  		dp->link_train.link_rate = reg;
  		dev_dbg(dp->dev, "final bandwidth = %.2x\n",
@@ -867,24 +929,32 @@ static int analogix_dp_config_video(struct analogix_dp_device *dp)
  	return 0;
  }
-static void analogix_dp_enable_scramble(struct analogix_dp_device *dp, 
-					bool enable)
+static int analogix_dp_enable_scramble(struct analogix_dp_device *dp,
+				       bool enable)
  {
  	u8 data;
+	int ret;
if (enable) { 
  		analogix_dp_enable_scrambling(dp);
- drm_dp_dpcd_readb(&dp->aux, DP_TRAINING_PATTERN_SET, &data); 
-		drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
+		ret = drm_dp_dpcd_readb(&dp->aux, DP_TRAINING_PATTERN_SET,
+					&data);
+		if (ret != 1)
+			return ret;
+		ret = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
  				   (u8)(data & ~DP_LINK_SCRAMBLING_DISABLE));
  	} else {
  		analogix_dp_disable_scrambling(dp);
- drm_dp_dpcd_readb(&dp->aux, DP_TRAINING_PATTERN_SET, &data); 
-		drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
+		ret = drm_dp_dpcd_readb(&dp->aux, DP_TRAINING_PATTERN_SET,
+					&data);
+		if (ret != 1)
+			return ret;
+		ret = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
  				   (u8)(data | DP_LINK_SCRAMBLING_DISABLE));
  	}
+	return ret < 0 ? ret : 0;
  }
static irqreturn_t analogix_dp_hardirq(int irq, void *arg) 
@@ -939,23 +1009,36 @@ static int analogix_dp_commit(struct analogix_dp_device *dp)
  		return ret;
  	}
- analogix_dp_enable_scramble(dp, 1); 
+	ret = analogix_dp_enable_scramble(dp, 1);
+	if (ret < 0) {
+		dev_err(dp->dev, "can not enable scramble\n");
+		return ret;
+	}
analogix_dp_init_video(dp); 
  	ret = analogix_dp_config_video(dp);
-	if (ret)
+	if (ret) {
  		dev_err(dp->dev, "unable to config video\n");
+		return ret;
+	}
/* Safe to enable the panel now */ 
  	if (dp->plat_data->panel) {
-		if (drm_panel_enable(dp->plat_data->panel))
+		ret = drm_panel_enable(dp->plat_data->panel);
+		if (ret) {
  			DRM_ERROR("failed to enable the panel\n");
+			return ret;
+		}
  	}
- dp->psr_enable = analogix_dp_detect_sink_psr(dp); 
+	ret = analogix_dp_detect_sink_psr(dp);
+	if (ret)
+		return ret;
+
  	if (dp->psr_enable)
-		analogix_dp_enable_sink_psr(dp);
-	return 0;
+		ret = analogix_dp_enable_sink_psr(dp);
+
+	return ret;
  }
/* 
@@ -1185,8 +1268,10 @@ static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
  	}
ret = analogix_dp_commit(dp); 
-	if (ret)
+	if (ret) {
+		DRM_ERROR("dp commit error, ret = %d\n", ret);
  		goto out_dp_init;
+	}
enable_irq(dp->irq); 
  	return 0;


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