Re: [RESEND PATCH v6 10/27] drm/bridge: analogix_dp: Check dpcd write/read status

["Jingoo Han" <jingoohan1@gmail.com>]

On Monday, April 23, 2018 6:50 AM, Enric Balletbo i Serra wrote:
> 
> From: Lin Huang <hl@rock-chips.com>
> 
> We need to check the dpcd write/read return value to see whether the
> write/read was successful
> 
> Cc: Kristian H. Kristensen <hoegsberg@chromium.org>
> Signed-off-by: Lin Huang <hl@rock-chips.com>
> Signed-off-by: zain wang <wzz@rock-chips.com>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Reviewed-by: Archit Taneja <architt@codeaurora.org>

Acked-by: Jingoo Han <jingoohan1@gmail.com>

Best regards,
Jingoo Han

> ---
> 
>  .../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 1e1743b59c77..75e61ebf6722 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;
> --
> 2.17.0