@@ -581,6 +581,25 @@ void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
}
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
@@ -592,36 +611,85 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_disable);
* 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) {
- if (bridge->funcs->atomic_post_disable) {
- struct drm_bridge_state *old_bridge_state;
+ 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);
+ }
+ }
+ }
- old_bridge_state =
- drm_atomic_get_old_bridge_state(old_state,
- bridge);
- if (WARN_ON(!old_bridge_state))
- return;
+ drm_atomic_bridge_call_post_disable(bridge, old_state);
- bridge->funcs->atomic_post_disable(bridge,
- old_bridge_state);
- } else if (bridge->funcs->post_disable) {
- bridge->funcs->post_disable(bridge);
- }
+ 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
@@ -633,32 +701,60 @@ 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;
+
+ 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);
+ }
+ }
- old_bridge_state =
- drm_atomic_get_old_bridge_state(old_state,
- iter);
- if (WARN_ON(!old_bridge_state))
- return;
+ drm_atomic_bridge_call_pre_enable(iter, old_state);
- iter->funcs->atomic_pre_enable(iter, old_bridge_state);
- } else if (iter->funcs->pre_enable) {
- iter->funcs->pre_enable(iter);
- }
+ if (iter->pre_enable_prev_first)
+ /* Jump all bridges that we have already pre_enabled */
+ iter = limit;
if (iter == bridge)
break;
@@ -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.
*/
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> --- drivers/gpu/drm/drm_bridge.c | 144 +++++++++++++++++++++++++++++------ include/drm/drm_bridge.h | 8 ++ 2 files changed, 128 insertions(+), 24 deletions(-)