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Diffstat (limited to 'drivers/gpu/drm/drm_bridge.c')
| -rw-r--r-- | drivers/gpu/drm/drm_bridge.c | 1230 |
1 files changed, 1230 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c new file mode 100644 index 000000000..d799ec14f --- /dev/null +++ b/drivers/gpu/drm/drm_bridge.c @@ -0,0 +1,1230 @@ +/* + * 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); + + if (iter == bridge) + break; + } +} +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) +{ + unsigned int i, num_in_bus_fmts = 0; + struct drm_bridge_state *cur_state; + 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 = 0; + 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"); |