Re: [PATCH v3 06/21] drm: Stop accessing encoder->bridge directly

[Neil Armstrong <narmstrong@baylibre.com>]

On 23/10/2019 17:44, Boris Brezillon wrote:
> We are about to replace the single-linked bridge list by a double-linked
> one based on list.h, leading to the suppression of the encoder->bridge
> field. But before we can do that we must provide a
> drm_bridge_chain_get_first_bridge() bridge helper and patch all drivers
> and core helpers to use it instead of directly accessing encoder->bridge.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---
>  drivers/gpu/drm/drm_atomic_helper.c    | 25 +++++++++++++++++--------
>  drivers/gpu/drm/drm_encoder.c          |  3 ++-
>  drivers/gpu/drm/drm_probe_helper.c     |  4 +++-
>  drivers/gpu/drm/msm/edp/edp_bridge.c   | 10 ++++++++--
>  drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 11 ++++++++---
>  include/drm/drm_bridge.h               | 15 +++++++++++++++
>  6 files changed, 53 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index cf678be58fa4..f02ddffd4960 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -419,6 +419,7 @@ mode_fixup(struct drm_atomic_state *state)
>  	for_each_new_connector_in_state(state, connector, new_conn_state, i) {
>  		const struct drm_encoder_helper_funcs *funcs;
>  		struct drm_encoder *encoder;
> +		struct drm_bridge *bridge;
>  
>  		WARN_ON(!!new_conn_state->best_encoder != !!new_conn_state->crtc);
>  
> @@ -435,7 +436,8 @@ mode_fixup(struct drm_atomic_state *state)
>  		encoder = new_conn_state->best_encoder;
>  		funcs = encoder->helper_private;
>  
> -		ret = drm_bridge_chain_mode_fixup(encoder->bridge,
> +		bridge = drm_bridge_chain_get_first_bridge(encoder);
> +		ret = drm_bridge_chain_mode_fixup(bridge,
>  					&new_crtc_state->mode,
>  					&new_crtc_state->adjusted_mode);
>  		if (!ret) {
> @@ -493,6 +495,7 @@ static enum drm_mode_status mode_valid_path(struct drm_connector *connector,
>  					    struct drm_crtc *crtc,
>  					    const struct drm_display_mode *mode)
>  {
> +	struct drm_bridge *bridge;
>  	enum drm_mode_status ret;
>  
>  	ret = drm_encoder_mode_valid(encoder, mode);
> @@ -502,7 +505,8 @@ static enum drm_mode_status mode_valid_path(struct drm_connector *connector,
>  		return ret;
>  	}
>  
> -	ret = drm_bridge_chain_mode_valid(encoder->bridge, mode);
> +	bridge = drm_bridge_chain_get_first_bridge(encoder);
> +	ret = drm_bridge_chain_mode_valid(bridge, mode);
>  	if (ret != MODE_OK) {
>  		DRM_DEBUG_ATOMIC("[BRIDGE] mode_valid() failed\n");
>  		return ret;
> @@ -985,6 +989,7 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
>  	for_each_oldnew_connector_in_state(old_state, connector, old_conn_state, new_conn_state, i) {
>  		const struct drm_encoder_helper_funcs *funcs;
>  		struct drm_encoder *encoder;
> +		struct drm_bridge *bridge;
>  
>  		/* Shut down everything that's in the changeset and currently
>  		 * still on. So need to check the old, saved state. */
> @@ -1021,7 +1026,8 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
>  		 * Each encoder has at most one connector (since we always steal
>  		 * it away), so we won't call disable hooks twice.
>  		 */
> -		drm_atomic_bridge_chain_disable(encoder->bridge, old_state);
> +		bridge = drm_bridge_chain_get_first_bridge(encoder);
> +		drm_atomic_bridge_chain_disable(bridge, old_state);
>  
>  		/* Right function depends upon target state. */
>  		if (funcs) {
> @@ -1035,7 +1041,7 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
>  				funcs->dpms(encoder, DRM_MODE_DPMS_OFF);
>  		}
>  
> -		drm_atomic_bridge_chain_post_disable(encoder->bridge,
> +		drm_atomic_bridge_chain_post_disable(bridge,
>  						     old_state);
>  	}
>  
> @@ -1190,6 +1196,7 @@ crtc_set_mode(struct drm_device *dev, struct drm_atomic_state *old_state)
>  		const struct drm_encoder_helper_funcs *funcs;
>  		struct drm_encoder *encoder;
>  		struct drm_display_mode *mode, *adjusted_mode;
> +		struct drm_bridge *bridge;
>  
>  		if (!new_conn_state->best_encoder)
>  			continue;
> @@ -1217,8 +1224,8 @@ crtc_set_mode(struct drm_device *dev, struct drm_atomic_state *old_state)
>  			funcs->mode_set(encoder, mode, adjusted_mode);
>  		}
>  
> -		drm_bridge_chain_mode_set(encoder->bridge, mode,
> -					  adjusted_mode);
> +		bridge = drm_bridge_chain_get_first_bridge(encoder);
> +		drm_bridge_chain_mode_set(bridge, mode, adjusted_mode);
>  	}
>  }
>  
> @@ -1317,6 +1324,7 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
>  	for_each_new_connector_in_state(old_state, connector, new_conn_state, i) {
>  		const struct drm_encoder_helper_funcs *funcs;
>  		struct drm_encoder *encoder;
> +		struct drm_bridge *bridge;
>  
>  		if (!new_conn_state->best_encoder)
>  			continue;
> @@ -1335,7 +1343,8 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
>  		 * Each encoder has at most one connector (since we always steal
>  		 * it away), so we won't call enable hooks twice.
>  		 */
> -		drm_atomic_bridge_chain_pre_enable(encoder->bridge, old_state);
> +		bridge = drm_bridge_chain_get_first_bridge(encoder);
> +		drm_atomic_bridge_chain_pre_enable(bridge, old_state);
>  
>  		if (funcs) {
>  			if (funcs->atomic_enable)
> @@ -1346,7 +1355,7 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
>  				funcs->commit(encoder);
>  		}
>  
> -		drm_atomic_bridge_chain_enable(encoder->bridge, old_state);
> +		drm_atomic_bridge_chain_enable(bridge, old_state);
>  	}
>  
>  	drm_atomic_helper_commit_writebacks(dev, old_state);
> diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
> index 80d88a55302e..4fe9e723e227 100644
> --- a/drivers/gpu/drm/drm_encoder.c
> +++ b/drivers/gpu/drm/drm_encoder.c
> @@ -167,9 +167,10 @@ void drm_encoder_cleanup(struct drm_encoder *encoder)
>  	 */
>  
>  	if (encoder->bridge) {
> -		struct drm_bridge *bridge = encoder->bridge;
> +		struct drm_bridge *bridge;
>  		struct drm_bridge *next;
>  
> +		bridge = drm_bridge_chain_get_first_bridge(encoder);
>  		while (bridge) {
>  			next = bridge->next;
>  			drm_bridge_detach(bridge);
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index c3ea722065c4..576b4b7dcd89 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -101,6 +101,7 @@ drm_mode_validate_pipeline(struct drm_display_mode *mode,
>  
>  	/* Step 2: Validate against encoders and crtcs */
>  	drm_connector_for_each_possible_encoder(connector, encoder) {
> +		struct drm_bridge *bridge;
>  		struct drm_crtc *crtc;
>  
>  		ret = drm_encoder_mode_valid(encoder, mode);
> @@ -112,7 +113,8 @@ drm_mode_validate_pipeline(struct drm_display_mode *mode,
>  			continue;
>  		}
>  
> -		ret = drm_bridge_chain_mode_valid(encoder->bridge, mode);
> +		bridge = drm_bridge_chain_get_first_bridge(encoder);
> +		ret = drm_bridge_chain_mode_valid(bridge, mode);
>  		if (ret != MODE_OK) {
>  			/* There is also no point in continuing for crtc check
>  			 * here. */
> diff --git a/drivers/gpu/drm/msm/edp/edp_bridge.c b/drivers/gpu/drm/msm/edp/edp_bridge.c
> index 2950bba4aca9..b65b5cc2dba2 100644
> --- a/drivers/gpu/drm/msm/edp/edp_bridge.c
> +++ b/drivers/gpu/drm/msm/edp/edp_bridge.c
> @@ -55,8 +55,14 @@ static void edp_bridge_mode_set(struct drm_bridge *bridge,
>  	DBG("set mode: " DRM_MODE_FMT, DRM_MODE_ARG(mode));
>  
>  	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
> -		if ((connector->encoder != NULL) &&
> -			(connector->encoder->bridge == bridge)) {
> +		struct drm_encoder *encoder = connector->encoder;
> +		struct drm_bridge *first_bridge;
> +
> +		if (!connector->encoder)
> +			continue;
> +
> +		first_bridge = drm_bridge_chain_get_first_bridge(encoder);
> +		if (bridge == first_bridge) {
>  			msm_edp_ctrl_timing_cfg(edp->ctrl,
>  				adjusted_mode, &connector->display_info);
>  			break;
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> index 2da46e3dc4ae..7a1f1e5f0326 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> @@ -14,6 +14,7 @@
>  
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_atomic_helper.h>
> +#include <drm/drm_bridge.h>
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_device.h>
>  #include <drm/drm_fb_cma_helper.h>
> @@ -680,9 +681,10 @@ static void rcar_du_crtc_atomic_enable(struct drm_crtc *crtc,
>  			rcdu->encoders[RCAR_DU_OUTPUT_LVDS0 + rcrtc->index];
>  		const struct drm_display_mode *mode =
>  			&crtc->state->adjusted_mode;
> +		struct drm_bridge *bridge;
>  
> -		rcar_lvds_clk_enable(encoder->base.bridge,
> -				     mode->clock * 1000);
> +		bridge = drm_bridge_chain_get_first_bridge(&encoder->base);
> +		rcar_lvds_clk_enable(bridge, mode->clock * 1000);
>  	}
>  
>  	rcar_du_crtc_start(rcrtc);
> @@ -702,12 +704,15 @@ static void rcar_du_crtc_atomic_disable(struct drm_crtc *crtc,
>  	    rstate->outputs == BIT(RCAR_DU_OUTPUT_DPAD0)) {
>  		struct rcar_du_encoder *encoder =
>  			rcdu->encoders[RCAR_DU_OUTPUT_LVDS0 + rcrtc->index];
> +		struct drm_bridge *bridge;
> +
>  
>  		/*
>  		 * Disable the LVDS clock output, see
>  		 * rcar_du_crtc_atomic_enable().
>  		 */
> -		rcar_lvds_clk_disable(encoder->base.bridge);
> +		bridge = drm_bridge_chain_get_first_bridge(&encoder->base);
> +		rcar_lvds_clk_disable(bridge);
>  	}
>  
>  	spin_lock_irq(&crtc->dev->event_lock);
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 8aeba83fcf31..27eef63ce0ff 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -25,6 +25,7 @@
>  
>  #include <linux/list.h>
>  #include <linux/ctype.h>
> +#include <drm/drm_encoder.h>
>  #include <drm/drm_mode_object.h>
>  #include <drm/drm_modes.h>
>  
> @@ -422,6 +423,20 @@ drm_bridge_chain_get_next_bridge(struct drm_bridge *bridge)
>  	return bridge->next;
>  }
>  
> +/**
> + * drm_bridge_chain_get_first_bridge() - Get the first bridge in the chain
> + * @encoder: encoder object
> + *
> + * RETURNS:
> + * the first bridge in the chain, or NULL if @encoder has no bridge attached
> + * to it.
> + */
> +static inline struct drm_bridge *
> +drm_bridge_chain_get_first_bridge(struct drm_encoder *encoder)
> +{
> +	return encoder->bridge;
> +}
> +
>  bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,
>  				 const struct drm_display_mode *mode,
>  				 struct drm_display_mode *adjusted_mode);
> 

Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>