[PATCH 06/12] drm/msm/dpu: make changes to dpu_encoder to support virtual encoder

[Marijn Suijten]

On 2022-02-04 13:17:19, Abhinav Kumar wrote:
> Make changes to dpu_encoder to support virtual encoder needed
> to support writeback for dpu.
> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 57 +++++++++++++++++++++--------
>  1 file changed, 42 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index e977c05..947069b 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -974,6 +974,7 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc,
>  	struct dpu_hw_blk *hw_ctl[MAX_CHANNELS_PER_ENC];
>  	struct dpu_hw_blk *hw_lm[MAX_CHANNELS_PER_ENC];
>  	struct dpu_hw_blk *hw_dspp[MAX_CHANNELS_PER_ENC] = { NULL };
> +	enum dpu_hw_blk_type blk_type;
>  	int num_lm, num_ctl, num_pp;
>  	int i, j;
>  
> @@ -1061,20 +1062,36 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc,
>  		phys->hw_pp = dpu_enc->hw_pp[i];
>  		phys->hw_ctl = to_dpu_hw_ctl(hw_ctl[i]);
>  
> +		if (phys->intf_mode == INTF_MODE_WB_LINE)
> +			blk_type = DPU_HW_BLK_WB;
> +		else
> +			blk_type = DPU_HW_BLK_INTF;
> +
>  		num_blk = dpu_rm_get_assigned_resources(&dpu_kms->rm,
> -			global_state, drm_enc->base.id, DPU_HW_BLK_INTF,
> +			global_state, drm_enc->base.id, blk_type,
>  			hw_blk, ARRAY_SIZE(hw_blk));
> -		for (j = 0; j < num_blk; j++) {
> -			struct dpu_hw_intf *hw_intf;
>  
> -			hw_intf = to_dpu_hw_intf(hw_blk[i]);
> -			if (hw_intf->idx == phys->intf_idx)
> -				phys->hw_intf = hw_intf;
> +		if (blk_type == DPU_HW_BLK_WB) {
> +			for (j = 0; j < num_blk; j++) {
> +				struct dpu_hw_wb *hw_wb;
> +
> +				hw_wb = to_dpu_hw_wb(hw_blk[i]);
> +				if (hw_wb->idx == phys->intf_idx)
> +					phys->hw_wb = hw_wb;
> +			}
> +		} else {
> +			for (j = 0; j < num_blk; j++) {
> +				struct dpu_hw_intf *hw_intf;
> +
> +				hw_intf = to_dpu_hw_intf(hw_blk[i]);
> +				if (hw_intf->idx == phys->intf_idx)
> +					phys->hw_intf = hw_intf;
> +			}

It appears the original bit of code iterates j from 0 to num_blks yet
only uses i as iteration value.  All of this code seems reentrant
meaning that executing it more than one times is redundant.  You've
adopted this mistake, though I'd argue it should use j in hw_blk[i] as
that follows the number of elements in hw_blk returned by
dpu_rm_get_assigned_resources.

I suggest to address this in a separate patch (I can send that too, feel
free to add my Reported-by otherwise) and rebase this patch on top of
that, substituting i with j here as well.  It seems to have been
introduced by b954fa6baaca ("drm/msm/dpu: Refactor rm iterator").

- Marijn

>  		}
>  
> -		if (!phys->hw_intf) {
> +		if (!phys->hw_intf && !phys->hw_wb) {
>  			DPU_ERROR_ENC(dpu_enc,
> -				      "no intf block assigned at idx: %d\n", i);
> +				      "no intf or WB block assigned at idx: %d\n", i);
>  			return;
>  		}
>  
> @@ -1224,15 +1241,22 @@ static void dpu_encoder_virt_disable(struct drm_encoder *drm_enc)
>  	mutex_unlock(&dpu_enc->enc_lock);
>  }
>  
> -static enum dpu_intf dpu_encoder_get_intf(struct dpu_mdss_cfg *catalog,
> +static enum dpu_intf dpu_encoder_get_intf_or_wb(struct dpu_mdss_cfg *catalog,
>  		enum dpu_intf_type type, u32 controller_id)
>  {
>  	int i = 0;
>  
> -	for (i = 0; i < catalog->intf_count; i++) {
> -		if (catalog->intf[i].type == type
> -		    && catalog->intf[i].controller_id == controller_id) {
> -			return catalog->intf[i].id;
> +	if (type != INTF_WB) {
> +		for (i = 0; i < catalog->intf_count; i++) {
> +			if (catalog->intf[i].type == type
> +				&& catalog->intf[i].controller_id == controller_id) {
> +				return catalog->intf[i].id;
> +			}
> +		}
> +	} else {
> +		for (i = 0; i < catalog->wb_count; i++) {
> +			if (catalog->wb[i].id == controller_id)
> +				return catalog->wb[i].id;
>  		}
>  	}
>  
> @@ -2096,6 +2120,9 @@ static int dpu_encoder_setup_display(struct dpu_encoder_virt *dpu_enc,
>  	case DRM_MODE_ENCODER_TMDS:
>  		intf_type = INTF_DP;
>  		break;
> +	case DRM_MODE_ENCODER_VIRTUAL:
> +		intf_type = INTF_WB;
> +		break;
>  	}
>  
>  	WARN_ON(disp_info->num_of_h_tiles < 1);
> @@ -2128,11 +2155,11 @@ static int dpu_encoder_setup_display(struct dpu_encoder_virt *dpu_enc,
>  		DPU_DEBUG("h_tile_instance %d = %d, split_role %d\n",
>  				i, controller_id, phys_params.split_role);
>  
> -		phys_params.intf_idx = dpu_encoder_get_intf(dpu_kms->catalog,
> +		phys_params.intf_idx = dpu_encoder_get_intf_or_wb(dpu_kms->catalog,
>  													intf_type,
>  													controller_id);
>  		if (phys_params.intf_idx == INTF_MAX) {
> -			DPU_ERROR_ENC(dpu_enc, "could not get intf: type %d, id %d\n",
> +			DPU_ERROR_ENC(dpu_enc, "could not get intf or wb: type %d, id %d\n",
>  						  intf_type, controller_id);
>  			ret = -EINVAL;
>  		}
> -- 
> 2.7.4
>