From: Dave Stevenson dave.stevenson@raspberrypi.com
[ Upstream commit 4fb912e5e19075874379cfcf074d90bd51ebf8ea ]
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@raspberryp... Signed-off-by: Maxime Ripard maxime@cerno.tech Stable-dep-of: dd9e329af723 ("drm/bridge: ti-sn65dsi83: Fix enable/disable flow to meet spec") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/drm_bridge.c | 145 +++++++++++++++++++++++++++++------ include/drm/drm_bridge.h | 8 ++ 2 files changed, 129 insertions(+), 24 deletions(-)
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 1545c50fd1c8f..7044e339a82cd 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -691,6 +691,25 @@ 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 @@ -702,36 +721,86 @@ 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) + /* 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 @@ -743,32 +812,60 @@ 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; diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index 288c6feda5de2..6b656ea23b964 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -768,6 +768,14 @@ 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. */