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Diffstat (limited to 'drivers/gpu/drm/drm_bridge.c')
| -rw-r--r-- | drivers/gpu/drm/drm_bridge.c | 1544 |
1 files changed, 1544 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c new file mode 100644 index 000000000000..8f355df883d8 --- /dev/null +++ b/drivers/gpu/drm/drm_bridge.c @@ -0,0 +1,1544 @@ +/* + * 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/debugfs.h> +#include <linux/err.h> +#include <linux/export.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_bridge.h> +#include <drm/drm_debugfs.h> +#include <drm/drm_edid.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. + */ + +/* Protect bridge_list and bridge_lingering_list */ +static DEFINE_MUTEX(bridge_lock); +static LIST_HEAD(bridge_list); +static LIST_HEAD(bridge_lingering_list); + +static void __drm_bridge_free(struct kref *kref) +{ + struct drm_bridge *bridge = container_of(kref, struct drm_bridge, refcount); + + mutex_lock(&bridge_lock); + list_del(&bridge->list); + mutex_unlock(&bridge_lock); + + if (bridge->funcs->destroy) + bridge->funcs->destroy(bridge); + + kfree(bridge->container); +} + +/** + * drm_bridge_get - Acquire a bridge reference + * @bridge: DRM bridge + * + * This function increments the bridge's refcount. + * + * Returns: + * Pointer to @bridge. + */ +struct drm_bridge *drm_bridge_get(struct drm_bridge *bridge) +{ + if (bridge) + kref_get(&bridge->refcount); + + return bridge; +} +EXPORT_SYMBOL(drm_bridge_get); + +/** + * drm_bridge_put - Release a bridge reference + * @bridge: DRM bridge + * + * This function decrements the bridge's reference count and frees the + * object if the reference count drops to zero. + */ +void drm_bridge_put(struct drm_bridge *bridge) +{ + if (bridge) + kref_put(&bridge->refcount, __drm_bridge_free); +} +EXPORT_SYMBOL(drm_bridge_put); + +/** + * drm_bridge_put_void - wrapper to drm_bridge_put() taking a void pointer + * + * @data: pointer to @struct drm_bridge, cast to a void pointer + * + * Wrapper of drm_bridge_put() to be used when a function taking a void + * pointer is needed, for example as a devm action. + */ +static void drm_bridge_put_void(void *data) +{ + struct drm_bridge *bridge = (struct drm_bridge *)data; + + drm_bridge_put(bridge); +} + +void *__devm_drm_bridge_alloc(struct device *dev, size_t size, size_t offset, + const struct drm_bridge_funcs *funcs) +{ + void *container; + struct drm_bridge *bridge; + int err; + + if (!funcs) { + dev_warn(dev, "Missing funcs pointer\n"); + return ERR_PTR(-EINVAL); + } + + container = kzalloc(size, GFP_KERNEL); + if (!container) + return ERR_PTR(-ENOMEM); + + bridge = container + offset; + INIT_LIST_HEAD(&bridge->list); + bridge->container = container; + bridge->funcs = funcs; + kref_init(&bridge->refcount); + + err = devm_add_action_or_reset(dev, drm_bridge_put_void, bridge); + if (err) + return ERR_PTR(err); + + return container; +} +EXPORT_SYMBOL(__devm_drm_bridge_alloc); + +/** + * drm_bridge_add - register a bridge + * + * @bridge: bridge control structure + * + * Add the given bridge to the global list of bridges, where they can be + * found by users via of_drm_find_bridge(). + * + * The bridge to be added must have been allocated by + * devm_drm_bridge_alloc(). + */ +void drm_bridge_add(struct drm_bridge *bridge) +{ + if (!bridge->container) + DRM_WARN("DRM bridge corrupted or not allocated by devm_drm_bridge_alloc()\n"); + + drm_bridge_get(bridge); + + /* + * If the bridge was previously added and then removed, it is now + * in bridge_lingering_list. Remove it or bridge_lingering_list will be + * corrupted when adding this bridge to bridge_list below. + */ + if (!list_empty(&bridge->list)) + list_del_init(&bridge->list); + + mutex_init(&bridge->hpd_mutex); + + if (bridge->ops & DRM_BRIDGE_OP_HDMI) + bridge->ycbcr_420_allowed = !!(bridge->supported_formats & + BIT(HDMI_COLORSPACE_YUV420)); + + 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 - unregister a bridge + * + * @bridge: bridge control structure + * + * Remove the given bridge from the global list of registered bridges, so + * it won't be found by users via of_drm_find_bridge(), and add it to the + * lingering bridge list, to keep track of it until its allocated memory is + * eventually freed. + */ +void drm_bridge_remove(struct drm_bridge *bridge) +{ + mutex_lock(&bridge_lock); + list_move_tail(&bridge->list, &bridge_lingering_list); + mutex_unlock(&bridge_lock); + + mutex_destroy(&bridge->hpd_mutex); + + drm_bridge_put(bridge); +} +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, +}; + +static bool drm_bridge_is_atomic(struct drm_bridge *bridge) +{ + return bridge->funcs->atomic_reset != NULL; +} + +/** + * 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. + * + * The bridge to be attached must have been previously added by + * drm_bridge_add(). + * + * 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 (!bridge->container) + DRM_WARN("DRM bridge corrupted or not allocated by devm_drm_bridge_alloc()\n"); + + if (list_empty(&bridge->list)) + DRM_WARN("Missing drm_bridge_add() before attach\n"); + + drm_bridge_get(bridge); + + if (previous && (!previous->dev || previous->encoder != encoder)) { + ret = -EINVAL; + goto err_put_bridge; + } + + if (bridge->dev) { + ret = -EBUSY; + goto err_put_bridge; + } + + 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, encoder, flags); + if (ret < 0) + goto err_reset_bridge; + } + + if (drm_bridge_is_atomic(bridge)) { + 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); + + if (ret != -EPROBE_DEFER) + DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n", + bridge->of_node, encoder->name, ret); + else + dev_err_probe(encoder->dev->dev, -EPROBE_DEFER, + "failed to attach bridge %pOF to encoder %s\n", + bridge->of_node, encoder->name); + +err_put_bridge: + drm_bridge_put(bridge); + 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 (drm_bridge_is_atomic(bridge)) + drm_atomic_private_obj_fini(&bridge->base); + + if (bridge->funcs->detach) + bridge->funcs->detach(bridge); + + list_del(&bridge->chain_node); + bridge->dev = NULL; + drm_bridge_put(bridge); +} + +/** + * 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_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 + * @state: atomic state being committed + * + * 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 *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) { + iter->funcs->atomic_disable(iter, 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 *state) +{ + if (state && bridge->funcs->atomic_post_disable) + bridge->funcs->atomic_post_disable(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 + * @state: atomic state being committed + * + * 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. + * + * Example: + * Bridge A ---> Bridge B ---> Bridge C ---> Bridge D ---> Bridge E + * + * With pre_enable_prev_first flag enable in Bridge B, D, E then the resulting + * @post_disable order would be, + * Bridge B, Bridge A, Bridge E, Bridge D, Bridge C. + * + * 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 *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; + } + + if (list_is_last(&next->chain_node, + &encoder->bridge_chain)) { + 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, + state); + } + } + } + + drm_atomic_bridge_call_post_disable(bridge, 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 *state) +{ + if (state && bridge->funcs->atomic_pre_enable) + bridge->funcs->atomic_pre_enable(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 + * @state: atomic state being committed + * + * 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. + * + * Example: + * Bridge A ---> Bridge B ---> Bridge C ---> Bridge D ---> Bridge E + * + * With pre_enable_prev_first flag enable in Bridge B, D, E then the resulting + * @pre_enable order would be, + * Bridge C, Bridge D, Bridge E, Bridge A, Bridge B. + * + * 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 *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 = next; + 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, state); + } + } + + drm_atomic_bridge_call_pre_enable(iter, 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 + * @state: atomic state being committed + * + * 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 *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) { + bridge->funcs->atomic_enable(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 __free(drm_bridge_put) = + drm_bridge_get_prev_bridge(cur_bridge); + u32 *in_bus_fmts; + int ret; + + 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; + u32 *out_bus_fmts; + int ret = 0; + + struct drm_bridge *last_bridge __free(drm_bridge_put) = + drm_bridge_get(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; + 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; + + struct drm_bridge *next_bridge __free(drm_bridge_put) = 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 + * @connector: attached connector + * + * 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, struct drm_connector *connector) +{ + if (!(bridge->ops & DRM_BRIDGE_OP_DETECT)) + return connector_status_unknown; + + return bridge->funcs->detect(bridge, connector); +} +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_edid_read - read 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.edid_read to get + * the EDID and return it. Otherwise return NULL. + * + * RETURNS: + * The retrieved EDID on success, or NULL otherwise. + */ +const struct drm_edid *drm_bridge_edid_read(struct drm_bridge *bridge, + struct drm_connector *connector) +{ + if (!(bridge->ops & DRM_BRIDGE_OP_EDID)) + return NULL; + + return bridge->funcs->edid_read(bridge, connector); +} +EXPORT_SYMBOL_GPL(drm_bridge_edid_read); + +/** + * 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 + +/** + * devm_drm_put_bridge - Release a bridge reference obtained via devm + * @dev: device that got the bridge via devm + * @bridge: pointer to a struct drm_bridge obtained via devm + * + * Same as drm_bridge_put() for bridge pointers obtained via devm functions + * such as devm_drm_bridge_alloc(). + * + * This function is a temporary workaround and MUST NOT be used. Manual + * handling of bridge lifetime is inherently unsafe. + */ +void devm_drm_put_bridge(struct device *dev, struct drm_bridge *bridge) +{ + devm_release_action(dev, drm_bridge_put_void, bridge); +} +EXPORT_SYMBOL(devm_drm_put_bridge); + +static void drm_bridge_debugfs_show_bridge(struct drm_printer *p, + struct drm_bridge *bridge, + unsigned int idx, + bool lingering) +{ + drm_printf(p, "bridge[%u]: %ps\n", idx, bridge->funcs); + + drm_printf(p, "\trefcount: %u%s\n", kref_read(&bridge->refcount), + lingering ? " [lingering]" : ""); + + drm_printf(p, "\ttype: [%d] %s\n", + bridge->type, + drm_get_connector_type_name(bridge->type)); + + /* The OF node could be freed after drm_bridge_remove() */ + if (bridge->of_node && !lingering) + drm_printf(p, "\tOF: %pOFfc\n", bridge->of_node); + + drm_printf(p, "\tops: [0x%x]", bridge->ops); + if (bridge->ops & DRM_BRIDGE_OP_DETECT) + drm_puts(p, " detect"); + if (bridge->ops & DRM_BRIDGE_OP_EDID) + drm_puts(p, " edid"); + if (bridge->ops & DRM_BRIDGE_OP_HPD) + drm_puts(p, " hpd"); + if (bridge->ops & DRM_BRIDGE_OP_MODES) + drm_puts(p, " modes"); + if (bridge->ops & DRM_BRIDGE_OP_HDMI) + drm_puts(p, " hdmi"); + drm_puts(p, "\n"); +} + +static int allbridges_show(struct seq_file *m, void *data) +{ + struct drm_printer p = drm_seq_file_printer(m); + struct drm_bridge *bridge; + unsigned int idx = 0; + + mutex_lock(&bridge_lock); + + list_for_each_entry(bridge, &bridge_list, list) + drm_bridge_debugfs_show_bridge(&p, bridge, idx++, false); + + list_for_each_entry(bridge, &bridge_lingering_list, list) + drm_bridge_debugfs_show_bridge(&p, bridge, idx++, true); + + mutex_unlock(&bridge_lock); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(allbridges); + +static int encoder_bridges_show(struct seq_file *m, void *data) +{ + struct drm_encoder *encoder = m->private; + struct drm_printer p = drm_seq_file_printer(m); + unsigned int idx = 0; + + drm_for_each_bridge_in_chain_scoped(encoder, bridge) + drm_bridge_debugfs_show_bridge(&p, bridge, idx++, false); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(encoder_bridges); + +void drm_bridge_debugfs_params(struct dentry *root) +{ + debugfs_create_file("bridges", 0444, root, NULL, &allbridges_fops); +} + +void drm_bridge_debugfs_encoder_params(struct dentry *root, + struct drm_encoder *encoder) +{ + /* bridges list */ + debugfs_create_file("bridges", 0444, root, encoder, &encoder_bridges_fops); +} + +MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>"); +MODULE_DESCRIPTION("DRM bridge infrastructure"); +MODULE_LICENSE("GPL and additional rights"); |