openwrt/target/linux/bcm27xx/patches-6.1/950-0034-drm-bridge-Introduce-pre_enable_upstream_first-to-al.patch
Álvaro Fernández Rojas 793f8ab62c bcm27xx: 6.1: add kernel patches
Add kernel patches for version 6.1.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
2023-06-09 19:12:30 +02:00

309 lines
9.5 KiB
Diff

From 5365030a003a6cb0c336202256341e4bc9d65d52 Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Thu, 16 Dec 2021 15:25:35 +0000
Subject: [PATCH] drm/bridge: Introduce pre_enable_upstream_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_upstream_first that any bridge can set
to swap the order of pre_enable (and post_disable) for that and the
immediately upstream bridge.
Should the immediately upstream bridge also set the
pre_enable_upstream_first flag, the bridge upstream of that will be called
before either of those which requested pre_enable_upstream_first.
eg:
- Panel
- Bridge 1
- Bridge 2 pre_enable_upstream_first
- Bridge 3
- Bridge 4 pre_enable_upstream_first
- Bridge 5 pre_enable_upstream_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>
---
drivers/gpu/drm/drm_bridge.c | 177 +++++++++++++++++++++++++----------
include/drm/drm_bridge.h | 8 ++
2 files changed, 137 insertions(+), 48 deletions(-)
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -547,20 +547,15 @@ EXPORT_SYMBOL(drm_bridge_chain_disable);
* encoder chain, starting from the first bridge to the last. These are called
* after completing the encoder's prepare op.
*
+ * If a bridge sets @pre_enable_upstream_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_bridge_chain_post_disable(struct drm_bridge *bridge)
{
- struct drm_encoder *encoder;
-
- if (!bridge)
- return;
-
- encoder = bridge->encoder;
- list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
- if (bridge->funcs->post_disable)
- bridge->funcs->post_disable(bridge);
- }
+ drm_atomic_bridge_chain_post_disable(bridge, NULL);
}
EXPORT_SYMBOL(drm_bridge_chain_post_disable);
@@ -602,24 +597,14 @@ EXPORT_SYMBOL(drm_bridge_chain_mode_set)
* chain, starting from the last bridge to the first. These are called
* before calling the encoder's commit op.
*
+ * If a bridge sets @pre_enable_upstream_first, then the @pre_enable for the
+ * previous bridge will be called before @pre_enable of this bridge.
+ *
* Note: the bridge passed should be the one closest to the encoder
*/
void drm_bridge_chain_pre_enable(struct drm_bridge *bridge)
{
- struct drm_encoder *encoder;
- struct drm_bridge *iter;
-
- if (!bridge)
- return;
-
- encoder = bridge->encoder;
- list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
- if (iter->funcs->pre_enable)
- iter->funcs->pre_enable(iter);
-
- if (iter == bridge)
- break;
- }
+ drm_atomic_bridge_chain_pre_enable(bridge, NULL);
}
EXPORT_SYMBOL(drm_bridge_chain_pre_enable);
@@ -691,6 +676,25 @@ void drm_atomic_bridge_chain_disable(str
}
EXPORT_SYMBOL(drm_atomic_bridge_chain_disable);
+static void drm_atomic_bridge_call_post_disable(struct drm_bridge *bridge,
+ struct drm_atomic_state *old_state)
+{
+ if (old_state && bridge->funcs->atomic_post_disable) {
+ 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_post_disable(bridge,
+ old_bridge_state);
+ } else if (bridge->funcs->post_disable) {
+ bridge->funcs->post_disable(bridge);
+ }
+}
+
/**
* drm_atomic_bridge_chain_post_disable - cleans up after disabling all bridges
* in the encoder chain
@@ -701,6 +705,9 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_di
* &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_upstream_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
*/
@@ -708,30 +715,75 @@ void drm_atomic_bridge_chain_post_disabl
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) {
- if (bridge->funcs->atomic_post_disable) {
- struct drm_bridge_state *old_bridge_state;
+ limit = NULL;
- old_bridge_state =
- drm_atomic_get_old_bridge_state(old_state,
- bridge);
- if (WARN_ON(!old_bridge_state))
- return;
+ if (!list_is_last(&bridge->chain_node, &encoder->bridge_chain)) {
+ next = list_next_entry(bridge, chain_node);
- bridge->funcs->atomic_post_disable(bridge,
- old_bridge_state);
- } else if (bridge->funcs->post_disable) {
- bridge->funcs->post_disable(bridge);
+ if (next->pre_enable_upstream_first) {
+ /* Downstream bridge had requested that upstream
+ * was enabled first, so disabled last
+ */
+ limit = next;
+
+ /* Find the next bridge that has NOT requested
+ * upstream to be enabled first / disabled last
+ */
+ list_for_each_entry_from(next, &encoder->bridge_chain,
+ chain_node) {
+ if (next->pre_enable_upstream_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)
+ 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
@@ -743,33 +795,62 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_po
* 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_upstream_first, then the pre_enable for the
+ * upstream 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;
- old_bridge_state =
- drm_atomic_get_old_bridge_state(old_state,
- iter);
- if (WARN_ON(!old_bridge_state))
- return;
+ list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
+ if (iter->pre_enable_upstream_first) {
+ next = iter;
+ limit = bridge;
+ list_for_each_entry_from_reverse(next,
+ &encoder->bridge_chain,
+ chain_node) {
+ if (next == bridge)
+ break;
+
+ if (!next->pre_enable_upstream_first) {
+ /* Found first bridge that does NOT
+ * request upstream 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 upstream bridge pre_enable
+ * in order.
+ */
+ if (next == iter)
+ /* At the first bridgge to request upstream
+ * bridges called first.
+ */
+ break;
- iter->funcs->atomic_pre_enable(iter, old_bridge_state);
- } else if (iter->funcs->pre_enable) {
- iter->funcs->pre_enable(iter);
+ drm_atomic_bridge_call_pre_enable(next, old_state);
+ }
}
+ drm_atomic_bridge_call_pre_enable(iter, old_state);
+
+ if (iter->pre_enable_upstream_first)
+ /* Jump all bridges that we have already pre_enabled
+ */
+ iter = limit;
+
if (iter == bridge)
break;
}
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -769,6 +769,14 @@ struct drm_bridge {
*/
bool interlace_allowed;
/**
+ * @pre_enable_upstream_first: The bridge requires that the upstream
+ * 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_upstream_first;
+ /**
* @ddc: Associated I2C adapter for DDC access, if any.
*/
struct i2c_adapter *ddc;