On 23/10/2019 17:44, Boris Brezillon wrote:
> So that each element in the chain can easily access its predecessor.
> This will be needed to support bus format negotiation between elements
> of the bridge chain.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
> ---
> Changes in v3:
> * None
>
> Changes in v2:
> * Adjust things to the "dummy encoder bridge" change (patch 2 in this
> series)
> ---
> drivers/gpu/drm/drm_bridge.c | 171 ++++++++++++++++++++++------------
> drivers/gpu/drm/drm_encoder.c | 16 +---
> include/drm/drm_bridge.h | 12 ++-
> include/drm/drm_encoder.h | 9 +-
> 4 files changed, 135 insertions(+), 73 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index 54c874493c57..c5cf8a9c4237 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -55,7 +55,7 @@
> * just provide additional hooks to get the desired output at the end of the
> * encoder chain.
> *
> - * Bridges can also be chained up using the &drm_bridge.next pointer.
> + * Bridges can also be chained up using the &drm_bridge.chain_node field.
> *
> * Both legacy CRTC helpers and the new atomic modeset helpers support bridges.
> */
> @@ -114,6 +114,7 @@ EXPORT_SYMBOL(drm_bridge_remove);
> int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
> struct drm_bridge *previous)
> {
> + LIST_HEAD(tmp_list);
> int ret;
>
> if (!encoder || !bridge)
> @@ -127,6 +128,7 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
>
> bridge->dev = encoder->dev;
> bridge->encoder = encoder;
> + list_add_tail(&bridge->chain_node, &tmp_list);
>
> if (bridge->funcs->attach) {
> ret = bridge->funcs->attach(bridge);
> @@ -138,9 +140,9 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
> }
>
> if (previous)
> - previous->next = bridge;
> + list_splice(&tmp_list, &previous->chain_node);
> else
> - encoder->bridge = bridge;
> + list_splice(&tmp_list, &encoder->bridge_chain);
>
> return 0;
> }
> @@ -157,6 +159,7 @@ void drm_bridge_detach(struct drm_bridge *bridge)
> if (bridge->funcs->detach)
> bridge->funcs->detach(bridge);
>
> + list_del(&bridge->chain_node);
> bridge->dev = NULL;
> }
>
> @@ -190,18 +193,22 @@ bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,
> const struct drm_display_mode *mode,
> struct drm_display_mode *adjusted_mode)
> {
> - bool ret = true;
> + struct drm_encoder *encoder;
>
> if (!bridge)
> return true;
>
> - if (bridge->funcs->mode_fixup)
> - ret = bridge->funcs->mode_fixup(bridge, mode, adjusted_mode);
> + encoder = bridge->encoder;
> + list_for_each_entry_from(bridge, &encoder->bridge_chain,
> + chain_node) {
> + if (!bridge->funcs->mode_fixup)
> + continue;
>
> - ret = ret && drm_bridge_chain_mode_fixup(bridge->next, mode,
> - adjusted_mode);
> + if (!bridge->funcs->mode_fixup(bridge, mode, adjusted_mode))
> + return false;
> + }
>
> - return ret;
> + return true;
> }
> EXPORT_SYMBOL(drm_bridge_chain_mode_fixup);
>
> @@ -224,18 +231,24 @@ enum drm_mode_status
> drm_bridge_chain_mode_valid(struct drm_bridge *bridge,
> const struct drm_display_mode *mode)
> {
> - enum drm_mode_status ret = MODE_OK;
> + struct drm_encoder *encoder;
>
> if (!bridge)
> - return ret;
> + return MODE_OK;
> +
> + encoder = bridge->encoder;
> + list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
> + enum drm_mode_status ret;
> +
> + if (!bridge->funcs->mode_valid)
> + continue;
>
> - if (bridge->funcs->mode_valid)
> ret = bridge->funcs->mode_valid(bridge, mode);
> + if (ret != MODE_OK)
> + return ret;
> + }
>
> - if (ret != MODE_OK)
> - return ret;
> -
> - return drm_bridge_chain_mode_valid(bridge->next, mode);
> + return MODE_OK;
> }
> EXPORT_SYMBOL(drm_bridge_chain_mode_valid);
>
> @@ -251,13 +264,20 @@ EXPORT_SYMBOL(drm_bridge_chain_mode_valid);
> */
> void drm_bridge_chain_disable(struct drm_bridge *bridge)
> {
> + struct drm_encoder *encoder;
> + struct drm_bridge *iter;
> +
> if (!bridge)
> return;
>
> - drm_bridge_chain_disable(bridge->next);
> + encoder = bridge->encoder;
> + list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
> + if (iter->funcs->disable)
> + iter->funcs->disable(iter);
>
> - if (bridge->funcs->disable)
> - bridge->funcs->disable(bridge);
> + if (iter == bridge)
> + break;
> + }
> }
> EXPORT_SYMBOL(drm_bridge_chain_disable);
>
> @@ -274,13 +294,16 @@ EXPORT_SYMBOL(drm_bridge_chain_disable);
> */
> void drm_bridge_chain_post_disable(struct drm_bridge *bridge)
> {
> + struct drm_encoder *encoder;
> +
> if (!bridge)
> return;
>
> - if (bridge->funcs->post_disable)
> - bridge->funcs->post_disable(bridge);
> -
> - drm_bridge_chain_post_disable(bridge->next);
> + encoder = bridge->encoder;
> + list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
> + if (bridge->funcs->post_disable)
> + bridge->funcs->post_disable(bridge);
> + }
> }
> EXPORT_SYMBOL(drm_bridge_chain_post_disable);
>
> @@ -300,13 +323,16 @@ void drm_bridge_chain_mode_set(struct drm_bridge *bridge,
> const struct drm_display_mode *mode,
> const struct drm_display_mode *adjusted_mode)
> {
> + struct drm_encoder *encoder;
> +
> if (!bridge)
> return;
>
> - if (bridge->funcs->mode_set)
> - bridge->funcs->mode_set(bridge, mode, adjusted_mode);
> -
> - drm_bridge_chain_mode_set(bridge->next, mode, adjusted_mode);
> + encoder = bridge->encoder;
> + list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
> + if (bridge->funcs->mode_set)
> + bridge->funcs->mode_set(bridge, mode, adjusted_mode);
> + }
> }
> EXPORT_SYMBOL(drm_bridge_chain_mode_set);
>
> @@ -323,13 +349,17 @@ EXPORT_SYMBOL(drm_bridge_chain_mode_set);
> */
> void drm_bridge_chain_pre_enable(struct drm_bridge *bridge)
> {
> + struct drm_encoder *encoder;
> + struct drm_bridge *iter;
> +
> if (!bridge)
> return;
>
> - drm_bridge_chain_pre_enable(bridge->next);
> -
> - if (bridge->funcs->pre_enable)
> - bridge->funcs->pre_enable(bridge);
> + encoder = bridge->encoder;
> + list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
> + if (iter->funcs->pre_enable)
> + iter->funcs->pre_enable(iter);
> + }
> }
> EXPORT_SYMBOL(drm_bridge_chain_pre_enable);
>
> @@ -345,13 +375,16 @@ EXPORT_SYMBOL(drm_bridge_chain_pre_enable);
> */
> void drm_bridge_chain_enable(struct drm_bridge *bridge)
> {
> + struct drm_encoder *encoder;
> +
> if (!bridge)
> return;
>
> - if (bridge->funcs->enable)
> - bridge->funcs->enable(bridge);
> -
> - drm_bridge_chain_enable(bridge->next);
> + encoder = bridge->encoder;
> + list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
> + if (bridge->funcs->enable)
> + bridge->funcs->enable(bridge);
> + }
> }
> EXPORT_SYMBOL(drm_bridge_chain_enable);
>
> @@ -370,15 +403,23 @@ EXPORT_SYMBOL(drm_bridge_chain_enable);
> void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
> struct drm_atomic_state *state)
> {
> + struct drm_encoder *encoder;
> + struct drm_bridge *iter;
> +
> if (!bridge)
> return;
>
> - drm_atomic_bridge_chain_disable(bridge->next, state);
> + encoder = bridge->encoder;
> + list_for_each_entry_reverse(iter, &encoder->bridge_chain,
> + chain_node) {
> + if (iter->funcs->atomic_disable)
> + iter->funcs->atomic_disable(iter, state);
> + else if (iter->funcs->disable)
> + iter->funcs->disable(iter);
>
> - if (bridge->funcs->atomic_disable)
> - bridge->funcs->atomic_disable(bridge, state);
> - else if (bridge->funcs->disable)
> - bridge->funcs->disable(bridge);
> + if (iter == bridge)
> + break;
> + }
> }
> EXPORT_SYMBOL(drm_atomic_bridge_chain_disable);
>
> @@ -398,15 +439,19 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_disable);
> void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
> struct drm_atomic_state *state)
> {
> + struct drm_encoder *encoder;
> +
> if (!bridge)
> return;
>
> - if (bridge->funcs->atomic_post_disable)
> - bridge->funcs->atomic_post_disable(bridge, state);
> - else if (bridge->funcs->post_disable)
> - bridge->funcs->post_disable(bridge);
> -
> - drm_atomic_bridge_chain_post_disable(bridge->next, state);
> + encoder = bridge->encoder;
> + list_for_each_entry_from(bridge, &encoder->bridge_chain,
> + chain_node) {
> + if (bridge->funcs->atomic_post_disable)
> + bridge->funcs->atomic_post_disable(bridge, state);
> + else if (bridge->funcs->post_disable)
> + bridge->funcs->post_disable(bridge);
> + }
> }
> EXPORT_SYMBOL(drm_atomic_bridge_chain_post_disable);
>
> @@ -426,15 +471,23 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_post_disable);
> void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
> struct drm_atomic_state *state)
> {
> + struct drm_encoder *encoder;
> + struct drm_bridge *iter;
> +
> if (!bridge)
> return;
>
> - drm_atomic_bridge_chain_pre_enable(bridge->next, state);
> + encoder = bridge->encoder;
> + list_for_each_entry_reverse(iter, &bridge->encoder->bridge_chain,
> + chain_node) {
> + if (iter->funcs->atomic_pre_enable)
> + iter->funcs->atomic_pre_enable(iter, state);
> + else if (iter->funcs->pre_enable)
> + iter->funcs->pre_enable(iter);
>
> - if (bridge->funcs->atomic_pre_enable)
> - bridge->funcs->atomic_pre_enable(bridge, state);
> - else if (bridge->funcs->pre_enable)
> - bridge->funcs->pre_enable(bridge);
> + if (iter == bridge)
> + break;
> + }
> }
> EXPORT_SYMBOL(drm_atomic_bridge_chain_pre_enable);
>
> @@ -453,15 +506,19 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_pre_enable);
> void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
> struct drm_atomic_state *state)
> {
> + struct drm_encoder *encoder;
> +
> if (!bridge)
> return;
>
> - if (bridge->funcs->atomic_enable)
> - bridge->funcs->atomic_enable(bridge, state);
> - else if (bridge->funcs->enable)
> - bridge->funcs->enable(bridge);
> -
> - drm_atomic_bridge_chain_enable(bridge->next, state);
> + encoder = bridge->encoder;
> + list_for_each_entry_from(bridge, &bridge->encoder->bridge_chain,
> + chain_node) {
> + if (bridge->funcs->atomic_enable)
> + bridge->funcs->atomic_enable(bridge, state);
> + else if (bridge->funcs->enable)
> + bridge->funcs->enable(bridge);
> + }
> }
> EXPORT_SYMBOL(drm_atomic_bridge_chain_enable);
>
> diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
> index 4fe9e723e227..e555281f43d4 100644
> --- a/drivers/gpu/drm/drm_encoder.c
> +++ b/drivers/gpu/drm/drm_encoder.c
> @@ -140,6 +140,7 @@ int drm_encoder_init(struct drm_device *dev,
> goto out_put;
> }
>
> + INIT_LIST_HEAD(&encoder->bridge_chain);
> list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
> encoder->index = dev->mode_config.num_encoder++;
>
> @@ -160,23 +161,16 @@ EXPORT_SYMBOL(drm_encoder_init);
> void drm_encoder_cleanup(struct drm_encoder *encoder)
> {
> struct drm_device *dev = encoder->dev;
> + struct drm_bridge *bridge, *next;
>
> /* Note that the encoder_list is considered to be static; should we
> * remove the drm_encoder at runtime we would have to decrement all
> * the indices on the drm_encoder after us in the encoder_list.
> */
>
> - if (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);
> - bridge = next;
> - }
> - }
> + list_for_each_entry_safe(bridge, next, &encoder->bridge_chain,
> + chain_node)
> + drm_bridge_detach(bridge);
>
> drm_mode_object_unregister(dev, &encoder->base);
> kfree(encoder->name);
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 27eef63ce0ff..3ab16c95e59e 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -384,8 +384,8 @@ struct drm_bridge {
> struct drm_device *dev;
> /** @encoder: encoder to which this bridge is connected */
> struct drm_encoder *encoder;
> - /** @next: the next bridge in the encoder chain */
> - struct drm_bridge *next;
> + /** @chain_node: used to form a bridge chain */
> + struct list_head chain_node;
> #ifdef CONFIG_OF
> /** @of_node: device node pointer to the bridge */
> struct device_node *of_node;
> @@ -420,7 +420,10 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
> static inline struct drm_bridge *
> drm_bridge_chain_get_next_bridge(struct drm_bridge *bridge)
> {
> - return bridge->next;
> + if (list_is_last(&bridge->chain_node, &bridge->encoder->bridge_chain))
> + return NULL;
> +
> + return list_next_entry(bridge, chain_node);
> }
>
> /**
> @@ -434,7 +437,8 @@ drm_bridge_chain_get_next_bridge(struct drm_bridge *bridge)
> static inline struct drm_bridge *
> drm_bridge_chain_get_first_bridge(struct drm_encoder *encoder)
> {
> - return encoder->bridge;
> + return list_first_entry_or_null(&encoder->bridge_chain,
> + struct drm_bridge, chain_node);
> }
>
> bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,
> diff --git a/include/drm/drm_encoder.h b/include/drm/drm_encoder.h
> index f06164f44efe..9b3dde177c81 100644
> --- a/include/drm/drm_encoder.h
> +++ b/include/drm/drm_encoder.h
> @@ -172,7 +172,14 @@ struct drm_encoder {
> * &drm_connector_state.crtc.
> */
> struct drm_crtc *crtc;
> - struct drm_bridge *bridge;
> +
> + /**
> + * @bridge_chain: Bridges attached to this encoder. The first entry of
> + * this list is always &drm_encoder.bridge. It may be followed by other
> + * bridge entities.
> + */
> + struct list_head bridge_chain;
> +
> const struct drm_encoder_funcs *funcs;
> const struct drm_encoder_helper_funcs *helper_private;
> };
>
Reviewed-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
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