Re: [PATCH v2] drm/msm/dpu: add display port support in DPU

[Sean Paul <sean-p7yTbzM4H96eqtR555YLDQ@public.gmane.org>]

On Tue, Nov 27, 2018 at 02:28:30PM -0800, Jeykumar Sankaran wrote:
> Add display port support in DPU by creating hooks
> for DP encoder enumeration and encoder mode
> initialization.
> 
> This change is based on the SDM845 Display port
> driver changes[1].
> 
> changes in v2:
> 	- rebase on [2] (Sean Paul)
> 	- remove unwanted error checks and
> 	  switch cases (Jordan Crouse)
> 
> [1] https://lwn.net/Articles/768265/
> [2] https://lkml.org/lkml/2018/11/17/87
> 
> Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c |  8 ++---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c     | 47 +++++++++++++++++++++++++----
>  2 files changed, 45 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index d3f4501..1f6b4b1 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -2015,7 +2015,7 @@ static int dpu_encoder_setup_display(struct dpu_encoder_virt *dpu_enc,
>  {
>  	int ret = 0;
>  	int i = 0;
> -	enum dpu_intf_type intf_type;
> +	enum dpu_intf_type intf_type = INTF_NONE;

dpu_intf_type seems unnecessary, you could just use the DRM_MODE_ENCODER_* value
directly?

>  	struct dpu_enc_phys_init_params phys_params;
>  
>  	if (!dpu_enc || !dpu_kms) {
> @@ -2038,9 +2038,9 @@ static int dpu_encoder_setup_display(struct dpu_encoder_virt *dpu_enc,
>  	case DRM_MODE_ENCODER_DSI:
>  		intf_type = INTF_DSI;
>  		break;
> -	default:
> -		DPU_ERROR_ENC(dpu_enc, "unsupported display interface type\n");
> -		return -EINVAL;
> +	case DRM_MODE_ENCODER_TMDS:
> +		intf_type = INTF_DP;
> +		break;
>  	}
>  
>  	WARN_ON(disp_info->num_of_h_tiles < 1);
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> index 985c855..7d931ae 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> @@ -473,6 +473,32 @@ static void _dpu_kms_initialize_dsi(struct drm_device *dev,
>  	}
>  }
>  
> +static void _dpu_kms_initialize_displayport(struct drm_device *dev,
> +					    struct msm_drm_private *priv,
> +					    struct dpu_kms *dpu_kms)
> +{
> +	struct drm_encoder *encoder = NULL;
> +	int rc;
> +
> +	if (!priv->dp)
> +		return;
> +
> +	encoder = dpu_encoder_init(dev, DRM_MODE_ENCODER_TMDS);
> +	if (IS_ERR(encoder)) {
> +		DPU_ERROR("encoder init failed for dsi display\n");
> +		return;
> +	}
> +
> +	rc = msm_dp_modeset_init(priv->dp, dev, encoder);
> +	if (rc) {
> +		DPU_ERROR("modeset_init failed for DP, rc = %d\n", rc);
> +		drm_encoder_cleanup(encoder);
> +		return;
> +	}
> +
> +	priv->encoders[priv->num_encoders++] = encoder;

No need to keep track of drm resources at the driver level, the core will do
this for you. So can you please add a patch preceding this one to remove the
priv->encoders/crtc/planes/connectors arrays?

> +}
> +
>  /**
>   * _dpu_kms_setup_displays - create encoders, bridges and connectors
>   *                           for underlying displays
> @@ -487,6 +513,8 @@ static void _dpu_kms_setup_displays(struct drm_device *dev,

Why are these functions voids? Seems like there are plenty of places for them to
fail :)

Let's add a patch to the beginning of this series to properly handle failures in
setup_displays and initialize_dsi

>  {
>  	_dpu_kms_initialize_dsi(dev, priv, dpu_kms);
>  
> +	_dpu_kms_initialize_displayport(dev, priv, dpu_kms);
> +
>  	/**
>  	 * Extend this function to initialize other
>  	 * types of displays
> @@ -723,13 +751,20 @@ static void _dpu_kms_set_encoder_mode(struct msm_kms *kms,
>  	info.capabilities = cmd_mode ? MSM_DISPLAY_CAP_CMD_MODE :
>  			MSM_DISPLAY_CAP_VID_MODE;
>  
> -	/* TODO: No support for DSI swap */
> -	for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
> -		if (priv->dsi[i]) {
> -			info.h_tile_instance[info.num_of_h_tiles] = i;
> -			info.num_of_h_tiles++;
> +	switch (info.intf_type) {
> +	case DRM_MODE_ENCODER_DSI:
> +		/* TODO: No support for DSI swap */
> +		for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
> +			if (priv->dsi[i]) {
> +				info.h_tile_instance[info.num_of_h_tiles] = i;
> +				info.num_of_h_tiles++;
> +			}
>  		}
> -	}
> +		break;
> +	case DRM_MODE_ENCODER_TMDS:
> +		info.num_of_h_tiles = 1;
> +		break;
> +	};
>  
>  	rc = dpu_encoder_setup(encoder->dev, encoder, &info);
>  	if (rc)
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 
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-- 
Sean Paul, Software Engineer, Google / Chromium OS
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