Staging
v0.7.0
v0.7.0
drm_bridge.c
/*
* Copyright (c) 2014 Samsung Electronics Co., Ltd
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sub license,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <linux/err.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <drm/drm_atomic_state_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_encoder.h>
#include "drm_crtc_internal.h"
/**
* DOC: overview
*
* &struct drm_bridge represents a device that hangs on to an encoder. These are
* handy when a regular &drm_encoder entity isn't enough to represent the entire
* encoder chain.
*
* A bridge is always attached to a single &drm_encoder at a time, but can be
* either connected to it directly, or through a chain of bridges::
*
* [ CRTC ---> ] Encoder ---> Bridge A ---> Bridge B
*
* Here, the output of the encoder feeds to bridge A, and that furthers feeds to
* bridge B. Bridge chains can be arbitrarily long, and shall be fully linear:
* Chaining multiple bridges to the output of a bridge, or the same bridge to
* the output of different bridges, is not supported.
*
* Display drivers are responsible for linking encoders with the first bridge
* in the chains. This is done by acquiring the appropriate bridge with
* of_drm_find_bridge() or drm_of_find_panel_or_bridge(), or creating it for a
* panel with drm_panel_bridge_add_typed() (or the managed version
* devm_drm_panel_bridge_add_typed()). Once acquired, the bridge shall be
* attached to the encoder with a call to drm_bridge_attach().
*
* Bridges are responsible for linking themselves with the next bridge in the
* chain, if any. This is done the same way as for encoders, with the call to
* drm_bridge_attach() occurring in the &drm_bridge_funcs.attach operation.
*
* Once these links are created, the bridges can participate along with encoder
* functions to perform mode validation and fixup (through
* drm_bridge_chain_mode_valid() and drm_atomic_bridge_chain_check()), mode
* setting (through drm_bridge_chain_mode_set()), enable (through
* drm_atomic_bridge_chain_pre_enable() and drm_atomic_bridge_chain_enable())
* and disable (through drm_atomic_bridge_chain_disable() and
* drm_atomic_bridge_chain_post_disable()). Those functions call the
* corresponding operations provided in &drm_bridge_funcs in sequence for all
* bridges in the chain.
*
* For display drivers that use the atomic helpers
* drm_atomic_helper_check_modeset(),
* drm_atomic_helper_commit_modeset_enables() and
* drm_atomic_helper_commit_modeset_disables() (either directly in hand-rolled
* commit check and commit tail handlers, or through the higher-level
* drm_atomic_helper_check() and drm_atomic_helper_commit_tail() or
* drm_atomic_helper_commit_tail_rpm() helpers), this is done transparently and
* requires no intervention from the driver. For other drivers, the relevant
* DRM bridge chain functions shall be called manually.
*
* Bridges also participate in implementing the &drm_connector at the end of
* the bridge chain. Display drivers may use the drm_bridge_connector_init()
* helper to create the &drm_connector, or implement it manually on top of the
* connector-related operations exposed by the bridge (see the overview
* documentation of bridge operations for more details).
*
* &drm_bridge, like &drm_panel, aren't &drm_mode_object entities like planes,
* CRTCs, encoders or connectors and hence are not visible to userspace. They
* just provide additional hooks to get the desired output at the end of the
* encoder chain.
*/
static DEFINE_MUTEX(bridge_lock);
static LIST_HEAD(bridge_list);
/**
* drm_bridge_add - add the given bridge to the global bridge list
*
* @bridge: bridge control structure
*/
void drm_bridge_add(struct drm_bridge *bridge)
{
mutex_init(&bridge->hpd_mutex);
mutex_lock(&bridge_lock);
list_add_tail(&bridge->list, &bridge_list);
mutex_unlock(&bridge_lock);
}
EXPORT_SYMBOL(drm_bridge_add);
/**
* drm_bridge_remove - remove the given bridge from the global bridge list
*
* @bridge: bridge control structure
*/
void drm_bridge_remove(struct drm_bridge *bridge)
{
mutex_lock(&bridge_lock);
list_del_init(&bridge->list);
mutex_unlock(&bridge_lock);
mutex_destroy(&bridge->hpd_mutex);
}
EXPORT_SYMBOL(drm_bridge_remove);
static struct drm_private_state *
drm_bridge_atomic_duplicate_priv_state(struct drm_private_obj *obj)
{
struct drm_bridge *bridge = drm_priv_to_bridge(obj);
struct drm_bridge_state *state;
state = bridge->funcs->atomic_duplicate_state(bridge);
return state ? &state->base : NULL;
}
static void
drm_bridge_atomic_destroy_priv_state(struct drm_private_obj *obj,
struct drm_private_state *s)
{
struct drm_bridge_state *state = drm_priv_to_bridge_state(s);
struct drm_bridge *bridge = drm_priv_to_bridge(obj);
bridge->funcs->atomic_destroy_state(bridge, state);
}
static const struct drm_private_state_funcs drm_bridge_priv_state_funcs = {
.atomic_duplicate_state = drm_bridge_atomic_duplicate_priv_state,
.atomic_destroy_state = drm_bridge_atomic_destroy_priv_state,
};
/**
* drm_bridge_attach - attach the bridge to an encoder's chain
*
* @encoder: DRM encoder
* @bridge: bridge to attach
* @previous: previous bridge in the chain (optional)
* @flags: DRM_BRIDGE_ATTACH_* flags
*
* Called by a kms driver to link the bridge to an encoder's chain. The previous
* argument specifies the previous bridge in the chain. If NULL, the bridge is
* linked directly at the encoder's output. Otherwise it is linked at the
* previous bridge's output.
*
* If non-NULL the previous bridge must be already attached by a call to this
* function.
*
* Note that bridges attached to encoders are auto-detached during encoder
* cleanup in drm_encoder_cleanup(), so drm_bridge_attach() should generally
* *not* be balanced with a drm_bridge_detach() in driver code.
*
* RETURNS:
* Zero on success, error code on failure
*/
int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
struct drm_bridge *previous,
enum drm_bridge_attach_flags flags)
{
int ret;
if (!encoder || !bridge)
return -EINVAL;
if (previous && (!previous->dev || previous->encoder != encoder))
return -EINVAL;
if (bridge->dev)
return -EBUSY;
bridge->dev = encoder->dev;
bridge->encoder = encoder;
if (previous)
list_add(&bridge->chain_node, &previous->chain_node);
else
list_add(&bridge->chain_node, &encoder->bridge_chain);
if (bridge->funcs->attach) {
ret = bridge->funcs->attach(bridge, flags);
if (ret < 0)
goto err_reset_bridge;
}
if (bridge->funcs->atomic_reset) {
struct drm_bridge_state *state;
state = bridge->funcs->atomic_reset(bridge);
if (IS_ERR(state)) {
ret = PTR_ERR(state);
goto err_detach_bridge;
}
drm_atomic_private_obj_init(bridge->dev, &bridge->base,
&state->base,
&drm_bridge_priv_state_funcs);
}
return 0;
err_detach_bridge:
if (bridge->funcs->detach)
bridge->funcs->detach(bridge);
err_reset_bridge:
bridge->dev = NULL;
bridge->encoder = NULL;
list_del(&bridge->chain_node);
return ret;
}
EXPORT_SYMBOL(drm_bridge_attach);
void drm_bridge_detach(struct drm_bridge *bridge)
{
if (WARN_ON(!bridge))
return;
if (WARN_ON(!bridge->dev))
return;
if (bridge->funcs->atomic_reset)
drm_atomic_private_obj_fini(&bridge->base);
if (bridge->funcs->detach)
bridge->funcs->detach(bridge);
list_del(&bridge->chain_node);
bridge->dev = NULL;
}
/**
* DOC: bridge operations
*
* Bridge drivers expose operations through the &drm_bridge_funcs structure.
* The DRM internals (atomic and CRTC helpers) use the helpers defined in
* drm_bridge.c to call bridge operations. Those operations are divided in
* three big categories to support different parts of the bridge usage.
*
* - The encoder-related operations support control of the bridges in the
* chain, and are roughly counterparts to the &drm_encoder_helper_funcs
* operations. They are used by the legacy CRTC and the atomic modeset
* helpers to perform mode validation, fixup and setting, and enable and
* disable the bridge automatically.
*
* The enable and disable operations are split in
* &drm_bridge_funcs.pre_enable, &drm_bridge_funcs.enable,
* &drm_bridge_funcs.disable and &drm_bridge_funcs.post_disable to provide
* finer-grained control.
*
* Bridge drivers may implement the legacy version of those operations, or
* the atomic version (prefixed with atomic\_), in which case they shall also
* implement the atomic state bookkeeping operations
* (&drm_bridge_funcs.atomic_duplicate_state,
* &drm_bridge_funcs.atomic_destroy_state and &drm_bridge_funcs.reset).
* Mixing atomic and non-atomic versions of the operations is not supported.
*
* - The bus format negotiation operations
* &drm_bridge_funcs.atomic_get_output_bus_fmts and
* &drm_bridge_funcs.atomic_get_input_bus_fmts allow bridge drivers to
* negotiate the formats transmitted between bridges in the chain when
* multiple formats are supported. Negotiation for formats is performed
* transparently for display drivers by the atomic modeset helpers. Only
* atomic versions of those operations exist, bridge drivers that need to
* implement them shall thus also implement the atomic version of the
* encoder-related operations. This feature is not supported by the legacy
* CRTC helpers.
*
* - The connector-related operations support implementing a &drm_connector
* based on a chain of bridges. DRM bridges traditionally create a
* &drm_connector for bridges meant to be used at the end of the chain. This
* puts additional burden on bridge drivers, especially for bridges that may
* be used in the middle of a chain or at the end of it. Furthermore, it
* requires all operations of the &drm_connector to be handled by a single
* bridge, which doesn't always match the hardware architecture.
*
* To simplify bridge drivers and make the connector implementation more
* flexible, a new model allows bridges to unconditionally skip creation of
* &drm_connector and instead expose &drm_bridge_funcs operations to support
* an externally-implemented &drm_connector. Those operations are
* &drm_bridge_funcs.detect, &drm_bridge_funcs.get_modes,
* &drm_bridge_funcs.get_edid, &drm_bridge_funcs.hpd_notify,
* &drm_bridge_funcs.hpd_enable and &drm_bridge_funcs.hpd_disable. When
* implemented, display drivers shall create a &drm_connector instance for
* each chain of bridges, and implement those connector instances based on
* the bridge connector operations.
*
* Bridge drivers shall implement the connector-related operations for all
* the features that the bridge hardware support. For instance, if a bridge
* supports reading EDID, the &drm_bridge_funcs.get_edid shall be
* implemented. This however doesn't mean that the DDC lines are wired to the
* bridge on a particular platform, as they could also be connected to an I2C
* controller of the SoC. Support for the connector-related operations on the
* running platform is reported through the &drm_bridge.ops flags. Bridge
* drivers shall detect which operations they can support on the platform
* (usually this information is provided by ACPI or DT), and set the
* &drm_bridge.ops flags for all supported operations. A flag shall only be
* set if the corresponding &drm_bridge_funcs operation is implemented, but
* an implemented operation doesn't necessarily imply that the corresponding
* flag will be set. Display drivers shall use the &drm_bridge.ops flags to
* decide which bridge to delegate a connector operation to. This mechanism
* allows providing a single static const &drm_bridge_funcs instance in
* bridge drivers, improving security by storing function pointers in
* read-only memory.
*
* In order to ease transition, bridge drivers may support both the old and
* new models by making connector creation optional and implementing the
* connected-related bridge operations. Connector creation is then controlled
* by the flags argument to the drm_bridge_attach() function. Display drivers
* that support the new model and create connectors themselves shall set the
* %DRM_BRIDGE_ATTACH_NO_CONNECTOR flag, and bridge drivers shall then skip
* connector creation. For intermediate bridges in the chain, the flag shall
* be passed to the drm_bridge_attach() call for the downstream bridge.
* Bridge drivers that implement the new model only shall return an error
* from their &drm_bridge_funcs.attach handler when the
* %DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is not set. New display drivers
* should use the new model, and convert the bridge drivers they use if
* needed, in order to gradually transition to the new model.
*/
/**
* drm_bridge_chain_mode_fixup - fixup proposed mode for all bridges in the
* encoder chain
* @bridge: bridge control structure
* @mode: desired mode to be set for the bridge
* @adjusted_mode: updated mode that works for this bridge
*
* Calls &drm_bridge_funcs.mode_fixup for all the bridges in the
* encoder chain, starting from the first bridge to the last.
*
* Note: the bridge passed should be the one closest to the encoder
*
* RETURNS:
* true on success, false on failure
*/
bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,
const struct drm_display_mode *mode,
struct drm_display_mode *adjusted_mode)
{
struct drm_encoder *encoder;
if (!bridge)
return true;
encoder = bridge->encoder;
list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
if (!bridge->funcs->mode_fixup)
continue;
if (!bridge->funcs->mode_fixup(bridge, mode, adjusted_mode))
return false;
}
return true;
}
EXPORT_SYMBOL(drm_bridge_chain_mode_fixup);
/**
* drm_bridge_chain_mode_valid - validate the mode against all bridges in the
* encoder chain.
* @bridge: bridge control structure
* @info: display info against which the mode shall be validated
* @mode: desired mode to be validated
*
* Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
* chain, starting from the first bridge to the last. If at least one bridge
* does not accept the mode the function returns the error code.
*
* Note: the bridge passed should be the one closest to the encoder.
*
* RETURNS:
* MODE_OK on success, drm_mode_status Enum error code on failure
*/
enum drm_mode_status
drm_bridge_chain_mode_valid(struct drm_bridge *bridge,
const struct drm_display_info *info,
const struct drm_display_mode *mode)
{
struct drm_encoder *encoder;
if (!bridge)
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;
ret = bridge->funcs->mode_valid(bridge, info, mode);
if (ret != MODE_OK)
return ret;
}
return MODE_OK;
}
EXPORT_SYMBOL(drm_bridge_chain_mode_valid);
/**
* drm_bridge_chain_disable - disables all bridges in the encoder chain
* @bridge: bridge control structure
*
* Calls &drm_bridge_funcs.disable op for all the bridges in the encoder
* chain, starting from the last bridge to the first. These are called before
* calling the encoder's prepare op.
*
* Note: the bridge passed should be the one closest to the encoder
*/
void drm_bridge_chain_disable(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->disable)
iter->funcs->disable(iter);
if (iter == bridge)
break;
}
}
EXPORT_SYMBOL(drm_bridge_chain_disable);
/**
* drm_bridge_chain_post_disable - cleans up after disabling all bridges in the
* encoder chain
* @bridge: bridge control structure
*
* Calls &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 the encoder's prepare op.
*
* 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);
}
}
EXPORT_SYMBOL(drm_bridge_chain_post_disable);
/**
* drm_bridge_chain_mode_set - set proposed mode for all bridges in the
* encoder chain
* @bridge: bridge control structure
* @mode: desired mode to be set for the encoder chain
* @adjusted_mode: updated mode that works for this encoder chain
*
* Calls &drm_bridge_funcs.mode_set op for all the bridges in the
* encoder chain, starting from the first bridge to the last.
*
* Note: the bridge passed should be the one closest to the encoder
*/
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;
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);
/**
* drm_bridge_chain_pre_enable - prepares for enabling all bridges in the
* encoder chain
* @bridge: bridge control structure
*
* Calls &drm_bridge_funcs.pre_enable op for all the bridges in the encoder
* chain, starting from the last bridge to the first. These are called
* before calling the encoder's commit op.
*
* 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);
}
}
EXPORT_SYMBOL(drm_bridge_chain_pre_enable);
/**
* drm_bridge_chain_enable - enables all bridges in the encoder chain
* @bridge: bridge control structure
*
* Calls &drm_bridge_funcs.enable op for all the bridges in the encoder
* chain, starting from the first bridge to the last. These are called
* after completing the encoder's commit op.
*
* Note that the bridge passed should be the one closest to the encoder
*/
void drm_bridge_chain_enable(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->enable)
bridge->funcs->enable(bridge);
}
}
EXPORT_SYMBOL(drm_bridge_chain_enable);
/**
* drm_atomic_bridge_chain_disable - disables all bridges in the encoder chain
* @bridge: bridge control structure
* @old_state: old atomic state
*
* Calls &drm_bridge_funcs.atomic_disable (falls back on
* &drm_bridge_funcs.disable) op for all the bridges in the encoder chain,
* starting from the last bridge to the first. These are called before calling
* &drm_encoder_helper_funcs.atomic_disable
*
* Note: the bridge passed should be the one closest to the encoder
*/
void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
struct drm_atomic_state *old_state)
{
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->atomic_disable) {
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;
iter->funcs->atomic_disable(iter, old_bridge_state);
} else if (iter->funcs->disable) {
iter->funcs->disable(iter);
}
if (iter == bridge)
break;
}
}
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,
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) {
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);
}
}
}
EXPORT_SYMBOL(drm_atomic_bridge_chain_post_disable);
/**
* drm_atomic_bridge_chain_pre_enable - prepares for enabling all bridges in
* the encoder chain
* @bridge: bridge control structure
* @old_state: old atomic state
*
* Calls &drm_bridge_funcs.atomic_pre_enable (falls back on
* &drm_bridge_funcs.pre_enable) op for all the bridges in the encoder chain,
* starting from the last bridge to the first. These are called before calling
* &drm_encoder_helper_funcs.atomic_enable
*
* 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;
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;
iter->funcs->atomic_pre_enable(iter, old_bridge_state);
} else if (iter->funcs->pre_enable) {
iter->funcs->pre_enable(iter);
}
if (iter == bridge)
break;
}
}
EXPORT_SYMBOL(drm_atomic_bridge_chain_pre_enable);
/**
* drm_atomic_bridge_chain_enable - enables all bridges in the encoder chain
* @bridge: bridge control structure
* @old_state: old atomic state
*
* Calls &drm_bridge_funcs.atomic_enable (falls back on
* &drm_bridge_funcs.enable) 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_enable
*
* Note: the bridge passed should be the one closest to the encoder
*/
void drm_atomic_bridge_chain_enable(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_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_enable(bridge, old_bridge_state);
} else if (bridge->funcs->enable) {
bridge->funcs->enable(bridge);
}
}
}
EXPORT_SYMBOL(drm_atomic_bridge_chain_enable);
static int drm_atomic_bridge_check(struct drm_bridge *bridge,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state)
{
if (bridge->funcs->atomic_check) {
struct drm_bridge_state *bridge_state;
int ret;
bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
bridge);
if (WARN_ON(!bridge_state))
return -EINVAL;
ret = bridge->funcs->atomic_check(bridge, bridge_state,
crtc_state, conn_state);
if (ret)
return ret;
} else if (bridge->funcs->mode_fixup) {
if (!bridge->funcs->mode_fixup(bridge, &crtc_state->mode,
&crtc_state->adjusted_mode))
return -EINVAL;
}
return 0;
}
static int select_bus_fmt_recursive(struct drm_bridge *first_bridge,
struct drm_bridge *cur_bridge,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state,
u32 out_bus_fmt)
{
struct drm_bridge_state *cur_state;
unsigned int num_in_bus_fmts, i;
struct drm_bridge *prev_bridge;
u32 *in_bus_fmts;
int ret;
prev_bridge = drm_bridge_get_prev_bridge(cur_bridge);
cur_state = drm_atomic_get_new_bridge_state(crtc_state->state,
cur_bridge);
/*
* If bus format negotiation is not supported by this bridge, let's
* pass MEDIA_BUS_FMT_FIXED to the previous bridge in the chain and
* hope that it can handle this situation gracefully (by providing
* appropriate default values).
*/
if (!cur_bridge->funcs->atomic_get_input_bus_fmts) {
if (cur_bridge != first_bridge) {
ret = select_bus_fmt_recursive(first_bridge,
prev_bridge, crtc_state,
conn_state,
MEDIA_BUS_FMT_FIXED);
if (ret)
return ret;
}
/*
* Driver does not implement the atomic state hooks, but that's
* fine, as long as it does not access the bridge state.
*/
if (cur_state) {
cur_state->input_bus_cfg.format = MEDIA_BUS_FMT_FIXED;
cur_state->output_bus_cfg.format = out_bus_fmt;
}
return 0;
}
/*
* If the driver implements ->atomic_get_input_bus_fmts() it
* should also implement the atomic state hooks.
*/
if (WARN_ON(!cur_state))
return -EINVAL;
in_bus_fmts = cur_bridge->funcs->atomic_get_input_bus_fmts(cur_bridge,
cur_state,
crtc_state,
conn_state,
out_bus_fmt,
&num_in_bus_fmts);
if (!num_in_bus_fmts)
return -ENOTSUPP;
else if (!in_bus_fmts)
return -ENOMEM;
if (first_bridge == cur_bridge) {
cur_state->input_bus_cfg.format = in_bus_fmts[0];
cur_state->output_bus_cfg.format = out_bus_fmt;
kfree(in_bus_fmts);
return 0;
}
for (i = 0; i < num_in_bus_fmts; i++) {
ret = select_bus_fmt_recursive(first_bridge, prev_bridge,
crtc_state, conn_state,
in_bus_fmts[i]);
if (ret != -ENOTSUPP)
break;
}
if (!ret) {
cur_state->input_bus_cfg.format = in_bus_fmts[i];
cur_state->output_bus_cfg.format = out_bus_fmt;
}
kfree(in_bus_fmts);
return ret;
}
/*
* This function is called by &drm_atomic_bridge_chain_check() just before
* calling &drm_bridge_funcs.atomic_check() on all elements of the chain.
* It performs bus format negotiation between bridge elements. The negotiation
* happens in reverse order, starting from the last element in the chain up to
* @bridge.
*
* Negotiation starts by retrieving supported output bus formats on the last
* bridge element and testing them one by one. The test is recursive, meaning
* that for each tested output format, the whole chain will be walked backward,
* and each element will have to choose an input bus format that can be
* transcoded to the requested output format. When a bridge element does not
* support transcoding into a specific output format -ENOTSUPP is returned and
* the next bridge element will have to try a different format. If none of the
* combinations worked, -ENOTSUPP is returned and the atomic modeset will fail.
*
* This implementation is relying on
* &drm_bridge_funcs.atomic_get_output_bus_fmts() and
* &drm_bridge_funcs.atomic_get_input_bus_fmts() to gather supported
* input/output formats.
*
* When &drm_bridge_funcs.atomic_get_output_bus_fmts() is not implemented by
* the last element of the chain, &drm_atomic_bridge_chain_select_bus_fmts()
* tries a single format: &drm_connector.display_info.bus_formats[0] if
* available, MEDIA_BUS_FMT_FIXED otherwise.
*
* When &drm_bridge_funcs.atomic_get_input_bus_fmts() is not implemented,
* &drm_atomic_bridge_chain_select_bus_fmts() skips the negotiation on the
* bridge element that lacks this hook and asks the previous element in the
* chain to try MEDIA_BUS_FMT_FIXED. It's up to bridge drivers to decide what
* to do in that case (fail if they want to enforce bus format negotiation, or
* provide a reasonable default if they need to support pipelines where not
* all elements support bus format negotiation).
*/
static int
drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state)
{
struct drm_connector *conn = conn_state->connector;
struct drm_encoder *encoder = bridge->encoder;
struct drm_bridge_state *last_bridge_state;
unsigned int i, num_out_bus_fmts;
struct drm_bridge *last_bridge;
u32 *out_bus_fmts;
int ret = 0;
last_bridge = list_last_entry(&encoder->bridge_chain,
struct drm_bridge, chain_node);
last_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
last_bridge);
if (last_bridge->funcs->atomic_get_output_bus_fmts) {
const struct drm_bridge_funcs *funcs = last_bridge->funcs;
/*
* If the driver implements ->atomic_get_output_bus_fmts() it
* should also implement the atomic state hooks.
*/
if (WARN_ON(!last_bridge_state))
return -EINVAL;
out_bus_fmts = funcs->atomic_get_output_bus_fmts(last_bridge,
last_bridge_state,
crtc_state,
conn_state,
&num_out_bus_fmts);
if (!num_out_bus_fmts)
return -ENOTSUPP;
else if (!out_bus_fmts)
return -ENOMEM;
} else {
num_out_bus_fmts = 1;
out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);
if (!out_bus_fmts)
return -ENOMEM;
if (conn->display_info.num_bus_formats &&
conn->display_info.bus_formats)
out_bus_fmts[0] = conn->display_info.bus_formats[0];
else
out_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
}
for (i = 0; i < num_out_bus_fmts; i++) {
ret = select_bus_fmt_recursive(bridge, last_bridge, crtc_state,
conn_state, out_bus_fmts[i]);
if (ret != -ENOTSUPP)
break;
}
kfree(out_bus_fmts);
return ret;
}
static void
drm_atomic_bridge_propagate_bus_flags(struct drm_bridge *bridge,
struct drm_connector *conn,
struct drm_atomic_state *state)
{
struct drm_bridge_state *bridge_state, *next_bridge_state;
struct drm_bridge *next_bridge;
u32 output_flags = 0;
bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
/* No bridge state attached to this bridge => nothing to propagate. */
if (!bridge_state)
return;
next_bridge = drm_bridge_get_next_bridge(bridge);
/*
* Let's try to apply the most common case here, that is, propagate
* display_info flags for the last bridge, and propagate the input
* flags of the next bridge element to the output end of the current
* bridge when the bridge is not the last one.
* There are exceptions to this rule, like when signal inversion is
* happening at the board level, but that's something drivers can deal
* with from their &drm_bridge_funcs.atomic_check() implementation by
* simply overriding the flags value we've set here.
*/
if (!next_bridge) {
output_flags = conn->display_info.bus_flags;
} else {
next_bridge_state = drm_atomic_get_new_bridge_state(state,
next_bridge);
/*
* No bridge state attached to the next bridge, just leave the
* flags to 0.
*/
if (next_bridge_state)
output_flags = next_bridge_state->input_bus_cfg.flags;
}
bridge_state->output_bus_cfg.flags = output_flags;
/*
* Propage the output flags to the input end of the bridge. Again, it's
* not necessarily what all bridges want, but that's what most of them
* do, and by doing that by default we avoid forcing drivers to
* duplicate the "dummy propagation" logic.
*/
bridge_state->input_bus_cfg.flags = output_flags;
}
/**
* drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain
* @bridge: bridge control structure
* @crtc_state: new CRTC state
* @conn_state: new connector state
*
* First trigger a bus format negotiation before calling
* &drm_bridge_funcs.atomic_check() (falls back on
* &drm_bridge_funcs.mode_fixup()) op for all the bridges in the encoder chain,
* starting from the last bridge to the first. These are called before calling
* &drm_encoder_helper_funcs.atomic_check()
*
* RETURNS:
* 0 on success, a negative error code on failure
*/
int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state)
{
struct drm_connector *conn = conn_state->connector;
struct drm_encoder *encoder;
struct drm_bridge *iter;
int ret;
if (!bridge)
return 0;
ret = drm_atomic_bridge_chain_select_bus_fmts(bridge, crtc_state,
conn_state);
if (ret)
return ret;
encoder = bridge->encoder;
list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
int ret;
/*
* Bus flags are propagated by default. If a bridge needs to
* tweak the input bus flags for any reason, it should happen
* in its &drm_bridge_funcs.atomic_check() implementation such
* that preceding bridges in the chain can propagate the new
* bus flags.
*/
drm_atomic_bridge_propagate_bus_flags(iter, conn,
crtc_state->state);
ret = drm_atomic_bridge_check(iter, crtc_state, conn_state);
if (ret)
return ret;
if (iter == bridge)
break;
}
return 0;
}
EXPORT_SYMBOL(drm_atomic_bridge_chain_check);
/**
* drm_bridge_detect - check if anything is attached to the bridge output
* @bridge: bridge control structure
*
* If the bridge supports output detection, as reported by the
* DRM_BRIDGE_OP_DETECT bridge ops flag, call &drm_bridge_funcs.detect for the
* bridge and return the connection status. Otherwise return
* connector_status_unknown.
*
* RETURNS:
* The detection status on success, or connector_status_unknown if the bridge
* doesn't support output detection.
*/
enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge)
{
if (!(bridge->ops & DRM_BRIDGE_OP_DETECT))
return connector_status_unknown;
return bridge->funcs->detect(bridge);
}
EXPORT_SYMBOL_GPL(drm_bridge_detect);
/**
* drm_bridge_get_modes - fill all modes currently valid for the sink into the
* @connector
* @bridge: bridge control structure
* @connector: the connector to fill with modes
*
* If the bridge supports output modes retrieval, as reported by the
* DRM_BRIDGE_OP_MODES bridge ops flag, call &drm_bridge_funcs.get_modes to
* fill the connector with all valid modes and return the number of modes
* added. Otherwise return 0.
*
* RETURNS:
* The number of modes added to the connector.
*/
int drm_bridge_get_modes(struct drm_bridge *bridge,
struct drm_connector *connector)
{
if (!(bridge->ops & DRM_BRIDGE_OP_MODES))
return 0;
return bridge->funcs->get_modes(bridge, connector);
}
EXPORT_SYMBOL_GPL(drm_bridge_get_modes);
/**
* drm_bridge_get_edid - get the EDID data of the connected display
* @bridge: bridge control structure
* @connector: the connector to read EDID for
*
* If the bridge supports output EDID retrieval, as reported by the
* DRM_BRIDGE_OP_EDID bridge ops flag, call &drm_bridge_funcs.get_edid to
* get the EDID and return it. Otherwise return NULL.
*
* RETURNS:
* The retrieved EDID on success, or NULL otherwise.
*/
struct edid *drm_bridge_get_edid(struct drm_bridge *bridge,
struct drm_connector *connector)
{
if (!(bridge->ops & DRM_BRIDGE_OP_EDID))
return NULL;
return bridge->funcs->get_edid(bridge, connector);
}
EXPORT_SYMBOL_GPL(drm_bridge_get_edid);
/**
* drm_bridge_hpd_enable - enable hot plug detection for the bridge
* @bridge: bridge control structure
* @cb: hot-plug detection callback
* @data: data to be passed to the hot-plug detection callback
*
* Call &drm_bridge_funcs.hpd_enable if implemented and register the given @cb
* and @data as hot plug notification callback. From now on the @cb will be
* called with @data when an output status change is detected by the bridge,
* until hot plug notification gets disabled with drm_bridge_hpd_disable().
*
* Hot plug detection is supported only if the DRM_BRIDGE_OP_HPD flag is set in
* bridge->ops. This function shall not be called when the flag is not set.
*
* Only one hot plug detection callback can be registered at a time, it is an
* error to call this function when hot plug detection is already enabled for
* the bridge.
*/
void drm_bridge_hpd_enable(struct drm_bridge *bridge,
void (*cb)(void *data,
enum drm_connector_status status),
void *data)
{
if (!(bridge->ops & DRM_BRIDGE_OP_HPD))
return;
mutex_lock(&bridge->hpd_mutex);
if (WARN(bridge->hpd_cb, "Hot plug detection already enabled\n"))
goto unlock;
bridge->hpd_cb = cb;
bridge->hpd_data = data;
if (bridge->funcs->hpd_enable)
bridge->funcs->hpd_enable(bridge);
unlock:
mutex_unlock(&bridge->hpd_mutex);
}
EXPORT_SYMBOL_GPL(drm_bridge_hpd_enable);
/**
* drm_bridge_hpd_disable - disable hot plug detection for the bridge
* @bridge: bridge control structure
*
* Call &drm_bridge_funcs.hpd_disable if implemented and unregister the hot
* plug detection callback previously registered with drm_bridge_hpd_enable().
* Once this function returns the callback will not be called by the bridge
* when an output status change occurs.
*
* Hot plug detection is supported only if the DRM_BRIDGE_OP_HPD flag is set in
* bridge->ops. This function shall not be called when the flag is not set.
*/
void drm_bridge_hpd_disable(struct drm_bridge *bridge)
{
if (!(bridge->ops & DRM_BRIDGE_OP_HPD))
return;
mutex_lock(&bridge->hpd_mutex);
if (bridge->funcs->hpd_disable)
bridge->funcs->hpd_disable(bridge);
bridge->hpd_cb = NULL;
bridge->hpd_data = NULL;
mutex_unlock(&bridge->hpd_mutex);
}
EXPORT_SYMBOL_GPL(drm_bridge_hpd_disable);
/**
* drm_bridge_hpd_notify - notify hot plug detection events
* @bridge: bridge control structure
* @status: output connection status
*
* Bridge drivers shall call this function to report hot plug events when they
* detect a change in the output status, when hot plug detection has been
* enabled by drm_bridge_hpd_enable().
*
* This function shall be called in a context that can sleep.
*/
void drm_bridge_hpd_notify(struct drm_bridge *bridge,
enum drm_connector_status status)
{
mutex_lock(&bridge->hpd_mutex);
if (bridge->hpd_cb)
bridge->hpd_cb(bridge->hpd_data, status);
mutex_unlock(&bridge->hpd_mutex);
}
EXPORT_SYMBOL_GPL(drm_bridge_hpd_notify);
#ifdef CONFIG_OF
/**
* of_drm_find_bridge - find the bridge corresponding to the device node in
* the global bridge list
*
* @np: device node
*
* RETURNS:
* drm_bridge control struct on success, NULL on failure
*/
struct drm_bridge *of_drm_find_bridge(struct device_node *np)
{
struct drm_bridge *bridge;
mutex_lock(&bridge_lock);
list_for_each_entry(bridge, &bridge_list, list) {
if (bridge->of_node == np) {
mutex_unlock(&bridge_lock);
return bridge;
}
}
mutex_unlock(&bridge_lock);
return NULL;
}
EXPORT_SYMBOL(of_drm_find_bridge);
#endif
MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
MODULE_DESCRIPTION("DRM bridge infrastructure");
MODULE_LICENSE("GPL and additional rights");