[PATCH v3 1/3] drm: allow real encoder to be passed for drm_writeback_connector

Laurent Pinchart laurent.pinchart at ideasonboard.com
Thu Mar 17 08:51:06 UTC 2022


Hi Abhinav,

Thank you for the patch.

On Wed, Mar 16, 2022 at 11:48:16AM -0700, Abhinav Kumar wrote:
> For some vendor driver implementations, display hardware can
> be shared between the encoder used for writeback and the physical
> display.
> 
> In addition resources such as clocks and interrupts can
> also be shared between writeback and the real encoder.
> 
> To accommodate such vendor drivers and hardware, allow
> real encoder to be passed for drm_writeback_connector using a new
> drm_writeback_connector_init_with_encoder() API.

The commit message doesn't match the commit.

> In addition, to preserve the same call flows for the existing
> users of drm_writeback_connector_init(), also allow passing
> possible_crtcs as a parameter so that encoder can be initialized
> with it.
> 
> changes in v3:
> 	- allow passing possible_crtcs for existing users of
> 	  drm_writeback_connector_init()
> 	- squash the vendor changes into the same commit so
> 	  that each patch in the series can compile individually
> 
> Co-developed-by: Kandpal Suraj <suraj.kandpal at intel.com>
> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> ---
>  .../drm/arm/display/komeda/komeda_wb_connector.c   |   3 +-
>  drivers/gpu/drm/arm/malidp_mw.c                    |   5 +-
>  drivers/gpu/drm/drm_writeback.c                    | 103 +++++++++++++--------
>  drivers/gpu/drm/rcar-du/rcar_du_writeback.c        |   5 +-
>  drivers/gpu/drm/vc4/vc4_txp.c                      |  19 ++--
>  drivers/gpu/drm/vkms/vkms_writeback.c              |   3 +-
>  include/drm/drm_writeback.h                        |  22 ++++-
>  7 files changed, 103 insertions(+), 57 deletions(-)
> 
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c b/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
> index e465cc4..40774e6 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
> @@ -155,7 +155,6 @@ static int komeda_wb_connector_add(struct komeda_kms_dev *kms,
>  	kwb_conn->wb_layer = kcrtc->master->wb_layer;
>  
>  	wb_conn = &kwb_conn->base;
> -	wb_conn->encoder.possible_crtcs = BIT(drm_crtc_index(&kcrtc->base));
>  
>  	formats = komeda_get_layer_fourcc_list(&mdev->fmt_tbl,
>  					       kwb_conn->wb_layer->layer_type,
> @@ -164,7 +163,7 @@ static int komeda_wb_connector_add(struct komeda_kms_dev *kms,
>  	err = drm_writeback_connector_init(&kms->base, wb_conn,
>  					   &komeda_wb_connector_funcs,
>  					   &komeda_wb_encoder_helper_funcs,
> -					   formats, n_formats);
> +					   formats, n_formats, BIT(drm_crtc_index(&kcrtc->base)));
>  	komeda_put_fourcc_list(formats);
>  	if (err) {
>  		kfree(kwb_conn);
> diff --git a/drivers/gpu/drm/arm/malidp_mw.c b/drivers/gpu/drm/arm/malidp_mw.c
> index f5847a7..b882066 100644
> --- a/drivers/gpu/drm/arm/malidp_mw.c
> +++ b/drivers/gpu/drm/arm/malidp_mw.c
> @@ -208,11 +208,12 @@ int malidp_mw_connector_init(struct drm_device *drm)
>  	struct malidp_drm *malidp = drm->dev_private;
>  	u32 *formats;
>  	int ret, n_formats;
> +	uint32_t possible_crtcs;
>  
>  	if (!malidp->dev->hw->enable_memwrite)
>  		return 0;
>  
> -	malidp->mw_connector.encoder.possible_crtcs = 1 << drm_crtc_index(&malidp->crtc);
> +	possible_crtcs = 1 << drm_crtc_index(&malidp->crtc);
>  	drm_connector_helper_add(&malidp->mw_connector.base,
>  				 &malidp_mw_connector_helper_funcs);
>  
> @@ -223,7 +224,7 @@ int malidp_mw_connector_init(struct drm_device *drm)
>  	ret = drm_writeback_connector_init(drm, &malidp->mw_connector,
>  					   &malidp_mw_connector_funcs,
>  					   &malidp_mw_encoder_helper_funcs,
> -					   formats, n_formats);
> +					   formats, n_formats, possible_crtcs);

Do you need the local variable ?

>  	kfree(formats);
>  	if (ret)
>  		return ret;
> diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
> index dccf4504..17c1471 100644
> --- a/drivers/gpu/drm/drm_writeback.c
> +++ b/drivers/gpu/drm/drm_writeback.c
> @@ -149,36 +149,15 @@ static const struct drm_encoder_funcs drm_writeback_encoder_funcs = {
>  	.destroy = drm_encoder_cleanup,
>  };
>  
> -/**
> - * drm_writeback_connector_init - Initialize a writeback connector and its properties
> - * @dev: DRM device
> - * @wb_connector: Writeback connector to initialize
> - * @con_funcs: Connector funcs vtable
> - * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder
> - * @formats: Array of supported pixel formats for the writeback engine
> - * @n_formats: Length of the formats array
> - *
> - * This function creates the writeback-connector-specific properties if they
> - * have not been already created, initializes the connector as
> - * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property
> - * values. It will also create an internal encoder associated with the
> - * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for
> - * the encoder helper.
> - *
> - * Drivers should always use this function instead of drm_connector_init() to
> - * set up writeback connectors.
> - *
> - * Returns: 0 on success, or a negative error code
> - */
> -int drm_writeback_connector_init(struct drm_device *dev,
> -				 struct drm_writeback_connector *wb_connector,
> -				 const struct drm_connector_funcs *con_funcs,
> -				 const struct drm_encoder_helper_funcs *enc_helper_funcs,
> -				 const u32 *formats, int n_formats)
> +static int drm_writeback_connector_setup(struct drm_device *dev,
> +		struct drm_writeback_connector *wb_connector,
> +		const struct drm_connector_funcs *con_funcs, const u32 *formats,
> +		int n_formats)
>  {
>  	struct drm_property_blob *blob;
> -	struct drm_connector *connector = &wb_connector->base;
>  	struct drm_mode_config *config = &dev->mode_config;
> +	struct drm_connector *connector = &wb_connector->base;
> +
>  	int ret = create_writeback_properties(dev);
>  
>  	if (ret != 0)
> @@ -186,15 +165,10 @@ int drm_writeback_connector_init(struct drm_device *dev,
>  
>  	blob = drm_property_create_blob(dev, n_formats * sizeof(*formats),
>  					formats);
> -	if (IS_ERR(blob))
> -		return PTR_ERR(blob);
> -
> -	drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs);
> -	ret = drm_encoder_init(dev, &wb_connector->encoder,
> -			       &drm_writeback_encoder_funcs,
> -			       DRM_MODE_ENCODER_VIRTUAL, NULL);
> -	if (ret)
> -		goto fail;
> +	if (IS_ERR(blob)) {
> +		ret = PTR_ERR(blob);
> +		return ret;
> +	}
>  
>  	connector->interlace_allowed = 0;
>  
> @@ -204,7 +178,7 @@ int drm_writeback_connector_init(struct drm_device *dev,
>  		goto connector_fail;
>  
>  	ret = drm_connector_attach_encoder(connector,
> -						&wb_connector->encoder);
> +						wb_connector->encoder);
>  	if (ret)
>  		goto attach_fail;
>  
> @@ -233,11 +207,62 @@ int drm_writeback_connector_init(struct drm_device *dev,
>  attach_fail:
>  	drm_connector_cleanup(connector);
>  connector_fail:
> -	drm_encoder_cleanup(&wb_connector->encoder);
> -fail:
>  	drm_property_blob_put(blob);
>  	return ret;
>  }
> +
> +/**
> + * drm_writeback_connector_init - Initialize a writeback connector and its properties
> + * using an internal encoder
> + *
> + * @dev: DRM device
> + * @wb_connector: Writeback connector to initialize
> + * @con_funcs: Connector funcs vtable
> + * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder
> + * @formats: Array of supported pixel formats for the writeback engine
> + * @n_formats: Length of the formats array
> + * @possible_crtcs: possible crtcs for the internal writeback encoder
> + *
> + * This function creates the writeback-connector-specific properties if they
> + * have not been already created, initializes the connector as
> + * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property
> + * values. It will also create an internal encoder associated with the
> + * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for
> + * the encoder helper.
> + *
> + * Drivers should always use this function instead of drm_connector_init() to
> + * set up writeback connectors.
> + *
> + * Returns: 0 on success, or a negative error code
> + */
> +int drm_writeback_connector_init(struct drm_device *dev,
> +		struct drm_writeback_connector *wb_connector,
> +		const struct drm_connector_funcs *con_funcs,
> +		const struct drm_encoder_helper_funcs *enc_helper_funcs,
> +		const u32 *formats, int n_formats, uint32_t possible_crtcs)
> +{
> +	int ret = 0;
> +
> +	wb_connector->encoder = &wb_connector->internal_encoder;
> +
> +	drm_encoder_helper_add(wb_connector->encoder, enc_helper_funcs);
> +
> +	wb_connector->encoder->possible_crtcs = possible_crtcs;
> +
> +	ret = drm_encoder_init(dev, wb_connector->encoder,
> +			       &drm_writeback_encoder_funcs,
> +			       DRM_MODE_ENCODER_VIRTUAL, NULL);
> +	if (ret)
> +		return ret;
> +
> +	ret = drm_writeback_connector_setup(dev, wb_connector, con_funcs, formats,
> +			n_formats);
> +
> +	if (ret)
> +		drm_encoder_cleanup(wb_connector->encoder);
> +
> +	return ret;
> +}

All this doesn't belong to this patch. Just add the possible_crtcs
argument to drm_writeback_connector_init() in 1/3, nothing else. One
functional change, one patch.

>  EXPORT_SYMBOL(drm_writeback_connector_init);
>  
>  int drm_writeback_set_fb(struct drm_connector_state *conn_state,
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_writeback.c b/drivers/gpu/drm/rcar-du/rcar_du_writeback.c
> index c79d125..1a610c0 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_writeback.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_writeback.c
> @@ -199,8 +199,9 @@ int rcar_du_writeback_init(struct rcar_du_device *rcdu,
>  			   struct rcar_du_crtc *rcrtc)
>  {
>  	struct drm_writeback_connector *wb_conn = &rcrtc->writeback;
> +	uint32_t possible_crtcs;
>  
> -	wb_conn->encoder.possible_crtcs = 1 << drm_crtc_index(&rcrtc->crtc);
> +	possible_crtcs = 1 << drm_crtc_index(&rcrtc->crtc);
>  	drm_connector_helper_add(&wb_conn->base,
>  				 &rcar_du_wb_conn_helper_funcs);
>  
> @@ -208,7 +209,7 @@ int rcar_du_writeback_init(struct rcar_du_device *rcdu,
>  					    &rcar_du_wb_conn_funcs,
>  					    &rcar_du_wb_enc_helper_funcs,
>  					    writeback_formats,
> -					    ARRAY_SIZE(writeback_formats));
> +					    ARRAY_SIZE(writeback_formats), possible_crtcs);

Same here, do you need the intermediate variable ?

And please add a line break after ARRAY_SIZE().

>  }
>  
>  void rcar_du_writeback_setup(struct rcar_du_crtc *rcrtc,
> diff --git a/drivers/gpu/drm/vc4/vc4_txp.c b/drivers/gpu/drm/vc4/vc4_txp.c
> index 9809ca3..32c4fb0 100644
> --- a/drivers/gpu/drm/vc4/vc4_txp.c
> +++ b/drivers/gpu/drm/vc4/vc4_txp.c
> @@ -151,6 +151,8 @@ struct vc4_txp {
>  
>  	struct platform_device *pdev;
>  
> +	struct drm_encoder drm_enc;
> +
>  	struct drm_writeback_connector connector;
>  
>  	void __iomem *regs;
> @@ -159,7 +161,7 @@ struct vc4_txp {
>  
>  static inline struct vc4_txp *encoder_to_vc4_txp(struct drm_encoder *encoder)
>  {
> -	return container_of(encoder, struct vc4_txp, connector.encoder);
> +	return container_of(encoder, struct vc4_txp, drm_enc);
>  }
>  
>  static inline struct vc4_txp *connector_to_vc4_txp(struct drm_connector *conn)
> @@ -467,6 +469,7 @@ static int vc4_txp_bind(struct device *dev, struct device *master, void *data)
>  	struct vc4_txp *txp;
>  	struct drm_crtc *crtc;
>  	struct drm_encoder *encoder;
> +	struct drm_writeback_connector *wb_conn;
>  	int ret, irq;
>  
>  	irq = platform_get_irq(pdev, 0);
> @@ -492,12 +495,14 @@ static int vc4_txp_bind(struct device *dev, struct device *master, void *data)
>  	txp->regset.regs = txp_regs;
>  	txp->regset.nregs = ARRAY_SIZE(txp_regs);
>  
> -	drm_connector_helper_add(&txp->connector.base,
> +	wb_conn = &txp->connector;
> +	wb_conn->encoder = &txp->drm_enc;
> +
> +	drm_connector_helper_add(&wb_conn->base,
>  				 &vc4_txp_connector_helper_funcs);
> -	ret = drm_writeback_connector_init(drm, &txp->connector,
> -					   &vc4_txp_connector_funcs,
> -					   &vc4_txp_encoder_helper_funcs,
> -					   drm_fmts, ARRAY_SIZE(drm_fmts));
> +	ret = drm_writeback_connector_init(drm, wb_conn,
> +			&vc4_txp_connector_funcs, &vc4_txp_encoder_helper_funcs,
> +			drm_fmts, ARRAY_SIZE(drm_fmts), 0);

Most of this also doesn't belong to this patch.

>  	if (ret)
>  		return ret;
>  
> @@ -506,7 +511,7 @@ static int vc4_txp_bind(struct device *dev, struct device *master, void *data)
>  	if (ret)
>  		return ret;
>  
> -	encoder = &txp->connector.encoder;
> +	encoder = txp->connector.encoder;
>  	encoder->possible_crtcs = drm_crtc_mask(crtc);
>  
>  	ret = devm_request_irq(dev, irq, vc4_txp_interrupt, 0,
> diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c
> index 8694227..381e7b7 100644
> --- a/drivers/gpu/drm/vkms/vkms_writeback.c
> +++ b/drivers/gpu/drm/vkms/vkms_writeback.c
> @@ -140,12 +140,11 @@ int vkms_enable_writeback_connector(struct vkms_device *vkmsdev)
>  {
>  	struct drm_writeback_connector *wb = &vkmsdev->output.wb_connector;
>  
> -	vkmsdev->output.wb_connector.encoder.possible_crtcs = 1;
>  	drm_connector_helper_add(&wb->base, &vkms_wb_conn_helper_funcs);
>  
>  	return drm_writeback_connector_init(&vkmsdev->drm, wb,
>  					    &vkms_wb_connector_funcs,
>  					    &vkms_wb_encoder_helper_funcs,
>  					    vkms_wb_formats,
> -					    ARRAY_SIZE(vkms_wb_formats));
> +					    ARRAY_SIZE(vkms_wb_formats), 1);
>  }
> diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
> index 9697d27..5e002bc 100644
> --- a/include/drm/drm_writeback.h
> +++ b/include/drm/drm_writeback.h
> @@ -25,13 +25,29 @@ struct drm_writeback_connector {
>  	struct drm_connector base;
>  
>  	/**
> -	 * @encoder: Internal encoder used by the connector to fulfill
> +	 * @encoder: handle to drm_encoder used by the connector to fulfill
>  	 * the DRM framework requirements. The users of the
>  	 * @drm_writeback_connector control the behaviour of the @encoder
>  	 * by passing the @enc_funcs parameter to drm_writeback_connector_init()
>  	 * function.
> +	 *
> +	 * For some vendor drivers, the hardware resources are shared between
> +	 * writeback encoder and rest of the display pipeline.
> +	 * To accommodate such cases, encoder is a handle to the real encoder
> +	 * hardware.
> +	 *
> +	 * For current existing writeback users, this shall continue to be the
> +	 * embedded encoder for the writeback connector.
> +	 *
> +	 */
> +	struct drm_encoder *encoder;
> +
> +	/**
> +	 * @internal_encoder: internal encoder used by writeback when
> +	 * a real encoder is not provided by the vendor drm drivers.
> +	 * @encoder will be assigned to this for those cases.
>  	 */
> -	struct drm_encoder encoder;
> +	struct drm_encoder internal_encoder;

None of this belong here.

>  
>  	/**
>  	 * @pixel_formats_blob_ptr:
> @@ -150,7 +166,7 @@ int drm_writeback_connector_init(struct drm_device *dev,
>  				 struct drm_writeback_connector *wb_connector,
>  				 const struct drm_connector_funcs *con_funcs,
>  				 const struct drm_encoder_helper_funcs *enc_helper_funcs,
> -				 const u32 *formats, int n_formats);
> +				 const u32 *formats, int n_formats, uint32_t possible_crtcs);
>  
>  int drm_writeback_set_fb(struct drm_connector_state *conn_state,
>  			 struct drm_framebuffer *fb);

-- 
Regards,

Laurent Pinchart


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