Re: [PATCH v3 07/21] drm/bridge: Make the bridge chain a double-linked list

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@collabora.com

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@baylibre.com