Re: [PATCH 10/12] drm/msm/dpu: initialize dpu encoder and connector for writeback

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

On 05/02/2022 00:17, Abhinav Kumar wrote:
> Initialize dpu encoder and connector for writeback if the
> target supports it in the catalog.
>
> Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 37 ++++++++++++-----
>   drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c     | 62 +++++++++++++++++++++++++++++
>   2 files changed, 88 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index b51a677..3746432 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -2066,7 +2066,7 @@ static void dpu_encoder_early_unregister(struct drm_encoder *encoder)
>   }
>   
>   static int dpu_encoder_virt_add_phys_encs(
> -		u32 display_caps,
> +		struct msm_display_info *disp_info,
>   		struct dpu_encoder_virt *dpu_enc,
>   		struct dpu_enc_phys_init_params *params)
>   {
> @@ -2085,7 +2085,7 @@ static int dpu_encoder_virt_add_phys_encs(
>   		return -EINVAL;
>   	}
>   
> -	if (display_caps & MSM_DISPLAY_CAP_VID_MODE) {
> +	if (disp_info->capabilities & MSM_DISPLAY_CAP_VID_MODE) {
>   		enc = dpu_encoder_phys_vid_init(params);
>   
>   		if (IS_ERR_OR_NULL(enc)) {
> @@ -2098,7 +2098,7 @@ static int dpu_encoder_virt_add_phys_encs(
>   		++dpu_enc->num_phys_encs;
>   	}
>   
> -	if (display_caps & MSM_DISPLAY_CAP_CMD_MODE) {
> +	if (disp_info->capabilities & MSM_DISPLAY_CAP_CMD_MODE) {
>   		enc = dpu_encoder_phys_cmd_init(params);
>   
>   		if (IS_ERR_OR_NULL(enc)) {
> @@ -2111,6 +2111,19 @@ static int dpu_encoder_virt_add_phys_encs(
>   		++dpu_enc->num_phys_encs;
>   	}
>   
> +	if (disp_info->intf_type == DRM_MODE_ENCODER_VIRTUAL) {
> +		enc = dpu_encoder_phys_wb_init(params);
> +
> +		if (IS_ERR_OR_NULL(enc)) {
> +			DPU_ERROR_ENC(dpu_enc, "failed to init wb enc: %ld\n",
> +					PTR_ERR(enc));
> +			return enc == NULL ? -EINVAL : PTR_ERR(enc);
> +		}
> +
> +		dpu_enc->phys_encs[dpu_enc->num_phys_encs] = enc;
> +		++dpu_enc->num_phys_encs;
> +	}
> +
>   	if (params->split_role == ENC_ROLE_SLAVE)
>   		dpu_enc->cur_slave = enc;
>   	else
> @@ -2199,9 +2212,8 @@ static int dpu_encoder_setup_display(struct dpu_encoder_virt *dpu_enc,
>   		}
>   
>   		if (!ret) {
> -			ret = dpu_encoder_virt_add_phys_encs(disp_info->capabilities,
> -												 dpu_enc,
> -												 &phys_params);
> +			ret = dpu_encoder_virt_add_phys_encs(disp_info,
> +					dpu_enc, &phys_params);
>   			if (ret)
>   				DPU_ERROR_ENC(dpu_enc, "failed to add phys encs\n");
>   		}
> @@ -2317,11 +2329,14 @@ struct drm_encoder *dpu_encoder_init(struct drm_device *dev,
>   	if (!dpu_enc)
>   		return ERR_PTR(-ENOMEM);
>   
> -	rc = drm_encoder_init(dev, &dpu_enc->base, &dpu_encoder_funcs,
> -			drm_enc_mode, NULL);
> -	if (rc) {
> -		devm_kfree(dev->dev, dpu_enc);
> -		return ERR_PTR(rc);
> +	/* this is handled by drm_writeback_connector_init for virtual encoder */
> +	if (drm_enc_mode != DRM_MODE_ENCODER_VIRTUAL) {
> +		rc = drm_encoder_init(dev, &dpu_enc->base, &dpu_encoder_funcs,
> +							  drm_enc_mode, NULL);
> +		if (rc) {
> +			devm_kfree(dev->dev, dpu_enc);
> +			return ERR_PTR(rc);
> +		}
>   	}
>   
>   	drm_encoder_helper_add(&dpu_enc->base, &dpu_encoder_helper_funcs);
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> index 47fe11a..6327ba9 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> @@ -1,5 +1,6 @@
>   // SPDX-License-Identifier: GPL-2.0-only
>   /*
> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
>    * Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
>    * Copyright (C) 2013 Red Hat
>    * Author: Rob Clark <robdclark@xxxxxxxxx>
> @@ -15,6 +16,7 @@
>   #include <drm/drm_crtc.h>
>   #include <drm/drm_file.h>
>   #include <drm/drm_vblank.h>
> +#include <drm/drm_writeback.h>
>   
>   #include "msm_drv.h"
>   #include "msm_mmu.h"
> @@ -29,6 +31,7 @@
>   #include "dpu_kms.h"
>   #include "dpu_plane.h"
>   #include "dpu_vbif.h"
> +#include "dpu_writeback.h"
>   
>   #define CREATE_TRACE_POINTS
>   #include "dpu_trace.h"
> @@ -642,6 +645,56 @@ static int _dpu_kms_initialize_displayport(struct drm_device *dev,
>   	return 0;
>   }
>   
> +static int _dpu_kms_initialize_writeback(struct drm_device *dev,
> +		struct msm_drm_private *priv, struct dpu_kms *dpu_kms)
> +{
> +	struct drm_encoder *encoder = NULL;
> +	struct msm_display_info info;
> +	int rc, i;
> +	const u32 *wb_formats;
> +	int n_formats;
> +
> +	encoder = dpu_encoder_init(dev, DRM_MODE_ENCODER_VIRTUAL);
> +	if (IS_ERR(encoder)) {
> +		DPU_ERROR("encoder init failed for dsi display\n");
> +		return PTR_ERR(encoder);
> +	}
> +
> +	memset(&info, 0, sizeof(info));
> +
> +	for (i = 0; i < dpu_kms->catalog->wb_count; i++) {
> +		if (dpu_kms->catalog->wb[i].id == WB_2) {
> +			wb_formats = dpu_kms->catalog->wb[i].format_list;
> +			n_formats = dpu_kms->catalog->wb[i].num_formats;
> +		}
> +	}

If there is no WB_2 in the catalog, then both wb_formats and n_formats 
would be unused. Also even if there is no WB_2 you'd still try creating 
the writeback below.

I'd suggest to move dpu_encoder_init() + dpu_writeback_init() + 
dpu_encoder_setup() to the separate function. Then you can loop over the 
catslog->wb[] and once WB_2 is found, call this new function.

> +
> +	rc = dpu_writeback_init(dev, encoder, encoder->helper_private, wb_formats,
> +			n_formats);
> +	if (rc) {
> +		DPU_ERROR("dpu_writeback_init, rc = %d\n", rc);
> +		drm_encoder_cleanup(encoder);
> +		return rc;
> +	}
> +
> +	priv->encoders[priv->num_encoders++] = encoder;
> +
> +	info.num_of_h_tiles = 1;
> +	/* use only WB idx 2 instance for DPU */
> +	info.h_tile_instance[0] = WB_2;
> +	info.capabilities = MSM_DISPLAY_CAP_HOT_PLUG | MSM_DISPLAY_CAP_EDID;

these two capabilities are unused in the code. I'd suggest to drop them 
from msm_drv.h at all.

> +	info.intf_type = encoder->encoder_type;
> +
> +	rc = dpu_encoder_setup(dev, encoder, &info);
> +	if (rc) {
> +		DPU_ERROR("failed to setup DPU encoder %d: rc:%d\n",
> +				  encoder->base.id, rc);
> +		return rc;
> +	}
> +
> +	return 0;
> +}
> +
>   /**
>    * _dpu_kms_setup_displays - create encoders, bridges and connectors
>    *                           for underlying displays
> @@ -668,6 +721,15 @@ static int _dpu_kms_setup_displays(struct drm_device *dev,
>   		return rc;
>   	}
>   
> +	/* Since WB isn't a driver check the catalog before initializing */
> +	if (dpu_kms->catalog->wb_count) {
> +		rc = _dpu_kms_initialize_writeback(dev, priv, dpu_kms);
> +		if (rc) {
> +			DPU_ERROR("initialize_WB failed, rc = %d\n", rc);
> +			return rc;
> +		}
> +	}
> +
>   	return rc;
>   }
>   


--
With best wishes
Dmitry