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drm/bridge: Introduce pre_enable_prev_first to alter bridge init order 

DSI sink devices typically want the DSI host powered up and configured
before they are powered up. pre_enable is the place this would normally
happen, but they are called in reverse order from panel/connector towards
the encoder, which is the "wrong" order.

Add a new flag pre_enable_prev_first that any bridge can set
to swap the order of pre_enable (and post_disable) for that and the
immediately previous bridge.
Should the immediately previous bridge also set the
pre_enable_prev_first flag, the previous bridge to that will be called
before either of those which requested pre_enable_prev_first.

eg:
- Panel
- Bridge 1
- Bridge 2 pre_enable_prev_first
- Bridge 3
- Bridge 4 pre_enable_prev_first
- Bridge 5 pre_enable_prev_first
- Bridge 6
- Encoder
Would result in pre_enable's being called as Panel, Bridge 1, Bridge 3,
Bridge 2, Bridge 6, Bridge 5, Bridge 4, Encoder.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Link: https://lore.kernel.org/r/20221205173328.1395350-5-dave.stevenson@raspberrypi.com
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
This commit is contained in:
Dave Stevenson 2022-12-05 17:33:26 +00:00 committed by Maxime Ripard
parent 4e910d9d13
commit 4fb912e5e1
No known key found for this signature in database
GPG Key ID: E3EF0D6F671851C5
2 changed files with 127 additions and 22 deletions
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165
drivers/gpu/drm/drm_bridge.c
View File

@ -581,30 +581,10 @@ void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
}
EXPORT_SYMBOL(drm_atomic_bridge_chain_disable);
/**
* drm_atomic_bridge_chain_post_disable - cleans up after disabling all bridges
* in the encoder chain
* @bridge: bridge control structure
* @old_state: old atomic state
*
* Calls &drm_bridge_funcs.atomic_post_disable (falls back on
* &drm_bridge_funcs.post_disable) op for all the bridges in the encoder chain,
* starting from the first bridge to the last. These are called after completing
* &drm_encoder_helper_funcs.atomic_disable
*
* Note: the bridge passed should be the one closest to the encoder
*/
void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
static void drm_atomic_bridge_call_post_disable(struct drm_bridge *bridge,
struct drm_atomic_state *old_state)
{
struct drm_encoder *encoder;
if (!bridge)
return;
encoder = bridge->encoder;
list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
if (bridge->funcs->atomic_post_disable) {
if (old_state && bridge->funcs->atomic_post_disable) {
struct drm_bridge_state *old_bridge_state;
old_bridge_state =
@ -619,9 +599,98 @@ void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
bridge->funcs->post_disable(bridge);
}
}
/**
* drm_atomic_bridge_chain_post_disable - cleans up after disabling all bridges
* in the encoder chain
* @bridge: bridge control structure
* @old_state: old atomic state
*
* Calls &drm_bridge_funcs.atomic_post_disable (falls back on
* &drm_bridge_funcs.post_disable) op for all the bridges in the encoder chain,
* starting from the first bridge to the last. These are called after completing
* &drm_encoder_helper_funcs.atomic_disable
*
* If a bridge sets @pre_enable_prev_first, then the @post_disable for that
* bridge will be called before the previous one to reverse the @pre_enable
* calling direction.
*
* Note: the bridge passed should be the one closest to the encoder
*/
void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
struct drm_atomic_state *old_state)
{
struct drm_encoder *encoder;
struct drm_bridge *next, *limit;
if (!bridge)
return;
encoder = bridge->encoder;
list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
limit = NULL;
if (!list_is_last(&bridge->chain_node, &encoder->bridge_chain)) {
next = list_next_entry(bridge, chain_node);
if (next->pre_enable_prev_first) {
/* next bridge had requested that prev
* was enabled first, so disabled last
*/
limit = next;
/* Find the next bridge that has NOT requested
* prev to be enabled first / disabled last
*/
list_for_each_entry_from(next, &encoder->bridge_chain,
chain_node) {
if (next->pre_enable_prev_first) {
next = list_prev_entry(next, chain_node);
limit = next;
break;
}
}
/* Call these bridges in reverse order */
list_for_each_entry_from_reverse(next, &encoder->bridge_chain,
chain_node) {
if (next == bridge)
break;
drm_atomic_bridge_call_post_disable(next,
old_state);
}
}
}
drm_atomic_bridge_call_post_disable(bridge, old_state);
if (limit)
/* Jump all bridges that we have already post_disabled */
bridge = limit;
}
}
EXPORT_SYMBOL(drm_atomic_bridge_chain_post_disable);
static void drm_atomic_bridge_call_pre_enable(struct drm_bridge *bridge,
struct drm_atomic_state *old_state)
{
if (old_state && bridge->funcs->atomic_pre_enable) {
struct drm_bridge_state *old_bridge_state;
old_bridge_state =
drm_atomic_get_old_bridge_state(old_state,
bridge);
if (WARN_ON(!old_bridge_state))
return;
bridge->funcs->atomic_pre_enable(bridge, old_bridge_state);
} else if (bridge->funcs->pre_enable) {
bridge->funcs->pre_enable(bridge);
}
}
/**
* drm_atomic_bridge_chain_pre_enable - prepares for enabling all bridges in
* the encoder chain
@ -633,32 +702,60 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_post_disable);
* starting from the last bridge to the first. These are called before calling
* &drm_encoder_helper_funcs.atomic_enable
*
* If a bridge sets @pre_enable_prev_first, then the pre_enable for the
* prev bridge will be called before pre_enable of this bridge.
*
* Note: the bridge passed should be the one closest to the encoder
*/
void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
struct drm_atomic_state *old_state)
{
struct drm_encoder *encoder;
struct drm_bridge *iter;
struct drm_bridge *iter, *next, *limit;
if (!bridge)
return;
encoder = bridge->encoder;
list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
if (iter->funcs->atomic_pre_enable) {
struct drm_bridge_state *old_bridge_state;
if (iter->pre_enable_prev_first) {
next = iter;
limit = bridge;
list_for_each_entry_from_reverse(next,
&encoder->bridge_chain,
chain_node) {
if (next == bridge)
break;
old_bridge_state =
drm_atomic_get_old_bridge_state(old_state,
iter);
if (WARN_ON(!old_bridge_state))
return;
iter->funcs->atomic_pre_enable(iter, old_bridge_state);
} else if (iter->funcs->pre_enable) {
iter->funcs->pre_enable(iter);
if (!next->pre_enable_prev_first) {
/* Found first bridge that does NOT
* request prev to be enabled first
*/
limit = list_prev_entry(next, chain_node);
break;
}
}
list_for_each_entry_from(next, &encoder->bridge_chain, chain_node) {
/* Call requested prev bridge pre_enable
* in order.
*/
if (next == iter)
/* At the first bridge to request prev
* bridges called first.
*/
break;
drm_atomic_bridge_call_pre_enable(next, old_state);
}
}
drm_atomic_bridge_call_pre_enable(iter, old_state);
if (iter->pre_enable_prev_first)
/* Jump all bridges that we have already pre_enabled */
iter = limit;
if (iter == bridge)
break;

8
include/drm/drm_bridge.h
View File

@ -744,6 +744,14 @@ struct drm_bridge {
* modes.
*/
bool interlace_allowed;
/**
* @pre_enable_prev_first: The bridge requires that the prev
* bridge @pre_enable function is called before its @pre_enable,
* and conversely for post_disable. This is most frequently a
* requirement for DSI devices which need the host to be initialised
* before the peripheral.
*/
bool pre_enable_prev_first;
/**
* @ddc: Associated I2C adapter for DDC access, if any.
*/