/* * 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/media-bus-format.h> #include <linux/module.h> #include <linux/mutex.h> #include <drm/drm_atomic_state_helper.h> #include <drm/drm_debugfs.h> #include <drm/drm_bridge.h> #include <drm/drm_encoder.h> #include <drm/drm_file.h> #include <drm/drm_of.h> #include <drm/drm_print.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. * * &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. */ /** * DOC: display driver integration * * Display drivers are responsible for linking encoders with the first bridge * in the chains. This is done by acquiring the appropriate bridge with * devm_drm_of_get_bridge(). 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). */ /** * DOC: special care dsi * * The interaction between the bridges and other frameworks involved in * the probing of the upstream driver and the bridge driver can be * challenging. Indeed, there's multiple cases that needs to be * considered: * * - The upstream driver doesn't use the component framework and isn't a * MIPI-DSI host. In this case, the bridge driver will probe at some * point and the upstream driver should try to probe again by returning * EPROBE_DEFER as long as the bridge driver hasn't probed. * * - The upstream driver doesn't use the component framework, but is a * MIPI-DSI host. The bridge device uses the MIPI-DCS commands to be * controlled. In this case, the bridge device is a child of the * display device and when it will probe it's assured that the display * device (and MIPI-DSI host) is present. The upstream driver will be * assured that the bridge driver is connected between the * &mipi_dsi_host_ops.attach and &mipi_dsi_host_ops.detach operations. * Therefore, it must run mipi_dsi_host_register() in its probe * function, and then run drm_bridge_attach() in its * &mipi_dsi_host_ops.attach hook. * * - The upstream driver uses the component framework and is a MIPI-DSI * host. The bridge device uses the MIPI-DCS commands to be * controlled. This is the same situation than above, and can run * mipi_dsi_host_register() in either its probe or bind hooks. * * - The upstream driver uses the component framework and is a MIPI-DSI * host. The bridge device uses a separate bus (such as I2C) to be * controlled. In this case, there's no correlation between the probe * of the bridge and upstream drivers, so care must be taken to avoid * an endless EPROBE_DEFER loop, with each driver waiting for the * other to probe. * * The ideal pattern to cover the last item (and all the others in the * MIPI-DSI host driver case) is to split the operations like this: * * - The MIPI-DSI host driver must run mipi_dsi_host_register() in its * probe hook. It will make sure that the MIPI-DSI host sticks around, * and that the driver's bind can be called. * * - In its probe hook, the bridge driver must try to find its MIPI-DSI * host, register as a MIPI-DSI device and attach the MIPI-DSI device * to its host. The bridge driver is now functional. * * - In its &struct mipi_dsi_host_ops.attach hook, the MIPI-DSI host can * now add its component. Its bind hook will now be called and since * the bridge driver is attached and registered, we can now look for * and attach it. * * At this point, we're now certain that both the upstream driver and * the bridge driver are functional and we can't have a deadlock-like * situation when probing. */ /** * DOC: dsi bridge operations * * DSI host interfaces are expected to be implemented as bridges rather than * encoders, however there are a few aspects of their operation that need to * be defined in order to provide a consistent interface. * * A DSI host should keep the PHY powered down until the pre_enable operation is * called. All lanes are in an undefined idle state up to this point, and it * must not be assumed that it is LP-11. * pre_enable should initialise the PHY, set the data lanes to LP-11, and the * clock lane to either LP-11 or HS depending on the mode_flag * %MIPI_DSI_CLOCK_NON_CONTINUOUS. * * Ordinarily the downstream bridge DSI peripheral pre_enable will have been * called before the DSI host. If the DSI peripheral requires LP-11 and/or * the clock lane to be in HS mode prior to pre_enable, then it can set the * &pre_enable_prev_first flag to request the pre_enable (and * post_disable) order to be altered to enable the DSI host first. * * Either the CRTC being enabled, or the DSI host enable operation should switch * the host to actively transmitting video on the data lanes. * * The reverse also applies. The DSI host disable operation or stopping the CRTC * should stop transmitting video, and the data lanes should return to the LP-11 * state. The DSI host &post_disable operation should disable the PHY. * If the &pre_enable_prev_first flag is set, then the DSI peripheral's * bridge &post_disable will be called before the DSI host's post_disable. * * Whilst it is valid to call &host_transfer prior to pre_enable or after * post_disable, the exact state of the lanes is undefined at this point. The * DSI host should initialise the interface, transmit the data, and then disable * the interface again. * * Ultra Low Power State (ULPS) is not explicitly supported by DRM. If * implemented, it therefore needs to be handled entirely within the DSI Host * driver. */ 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); static void drm_bridge_remove_void(void *bridge) { drm_bridge_remove(bridge); } /** * devm_drm_bridge_add - devm managed version of drm_bridge_add() * * @dev: device to tie the bridge lifetime to * @bridge: bridge control structure * * This is the managed version of drm_bridge_add() which automatically * calls drm_bridge_remove() when @dev is unbound. * * Return: 0 if no error or negative error code. */ int devm_drm_bridge_add(struct device *dev, struct drm_bridge *bridge) { drm_bridge_add(bridge); return devm_add_action_or_reset(dev, drm_bridge_remove_void, bridge); } EXPORT_SYMBOL(devm_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); #ifdef CONFIG_OF DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n", bridge->of_node, encoder->name, ret); #else DRM_ERROR("failed to attach bridge to encoder %s: %d\n", encoder->name, ret); #endif 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_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_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); 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 * @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 * * 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) { 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); } } } drm_atomic_bridge_call_post_disable(bridge, old_state); 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 * @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 * * 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, *next, *limit; if (!bridge) return; encoder = bridge->encoder; list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) { 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); } } drm_atomic_bridge_call_pre_enable(iter, old_state); if (iter->pre_enable_prev_first) /* Jump all bridges that we have already pre_enabled */ iter = limit; 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; /* * Propagate 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 #ifdef CONFIG_DEBUG_FS static int drm_bridge_chains_info(struct seq_file *m, void *data) { struct drm_debugfs_entry *entry = m->private; struct drm_device *dev = entry->dev; struct drm_printer p = drm_seq_file_printer(m); struct drm_mode_config *config = &dev->mode_config; struct drm_encoder *encoder; unsigned int bridge_idx = 0; list_for_each_entry(encoder, &config->encoder_list, head) { struct drm_bridge *bridge; drm_printf(&p, "encoder[%u]\n", encoder->base.id); drm_for_each_bridge_in_chain(encoder, bridge) { drm_printf(&p, "\tbridge[%u] type: %u, ops: %#x", bridge_idx, bridge->type, bridge->ops); #ifdef CONFIG_OF if (bridge->of_node) drm_printf(&p, ", OF: %pOFfc", bridge->of_node); #endif drm_printf(&p, "\n"); bridge_idx++; } } return 0; } static const struct drm_debugfs_info drm_bridge_debugfs_list[] = { { "bridge_chains", drm_bridge_chains_info, 0 }, }; void drm_bridge_debugfs_init(struct drm_minor *minor) { drm_debugfs_add_files(minor->dev, drm_bridge_debugfs_list, ARRAY_SIZE(drm_bridge_debugfs_list)); } #endif MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>"); MODULE_DESCRIPTION("DRM bridge infrastructure"); MODULE_LICENSE("GPL and additional rights"