encoder代码分析 ==================== struct drm_encoder结构体 --------------------------- :: struct drm_encoder { struct drm_device *dev; struct list_head head; struct drm_mode_object base; char *name; /** * @encoder_type: * * One of the DRM_MODE_ENCODER_ types in drm_mode.h. The following * encoder types are defined thus far: * * - DRM_MODE_ENCODER_DAC for VGA and analog on DVI-I/DVI-A. * * - DRM_MODE_ENCODER_TMDS for DVI, HDMI and (embedded) DisplayPort. * * - DRM_MODE_ENCODER_LVDS for display panels, or in general any panel * with a proprietary parallel connector. * * - DRM_MODE_ENCODER_TVDAC for TV output (Composite, S-Video, * Component, SCART). * * - DRM_MODE_ENCODER_VIRTUAL for virtual machine displays * * - DRM_MODE_ENCODER_DSI for panels connected using the DSI serial bus. * * - DRM_MODE_ENCODER_DPI for panels connected using the DPI parallel * bus. * * - DRM_MODE_ENCODER_DPMST for special fake encoders used to allow * mutliple DP MST streams to share one physical encoder. */ int encoder_type; /** * @index: Position inside the mode_config.list, can be used as an array * index. It is invariant over the lifetime of the encoder. */ unsigned index; /** * @possible_crtcs: Bitmask of potential CRTC bindings, using * drm_crtc_index() as the index into the bitfield. The driver must set * the bits for all &drm_crtc objects this encoder can be connected to * before calling drm_encoder_init(). * * In reality almost every driver gets this wrong. * * Note that since CRTC objects can't be hotplugged the assigned indices * are stable and hence known before registering all objects. */ uint32_t possible_crtcs; /** * @possible_clones: Bitmask of potential sibling encoders for cloning, * using drm_encoder_index() as the index into the bitfield. The driver * must set the bits for all &drm_encoder objects which can clone a * &drm_crtc together with this encoder before calling * drm_encoder_init(). Drivers should set the bit representing the * encoder itself, too. Cloning bits should be set such that when two * encoders can be used in a cloned configuration, they both should have * each another bits set. * * In reality almost every driver gets this wrong. * * Note that since encoder objects can't be hotplugged the assigned indices * are stable and hence known before registering all objects. */ uint32_t possible_clones; /** * @crtc: Currently bound CRTC, only really meaningful for non-atomic * drivers. Atomic drivers should instead check * &drm_connector_state.crtc. */ struct drm_crtc *crtc; struct drm_bridge *bridge; const struct drm_encoder_funcs *funcs; const struct drm_encoder_helper_funcs *helper_private; }; - encoder_type :: static const struct drm_prop_enum_list drm_encoder_enum_list[] = { { DRM_MODE_ENCODER_NONE, "None" }, { DRM_MODE_ENCODER_DAC, "DAC" }, { DRM_MODE_ENCODER_TMDS, "TMDS" }, { DRM_MODE_ENCODER_LVDS, "LVDS" }, { DRM_MODE_ENCODER_TVDAC, "TV" }, { DRM_MODE_ENCODER_VIRTUAL, "Virtual" }, { DRM_MODE_ENCODER_DSI, "DSI" }, { DRM_MODE_ENCODER_DPMST, "DP MST" }, { DRM_MODE_ENCODER_DPI, "DPI" }, }; - struct drm_encoder_funcs :: struct drm_encoder_funcs { /** * @reset: * * Reset encoder hardware and software state to off. This function isn't * called by the core directly, only through drm_mode_config_reset(). * It's not a helper hook only for historical reasons. */ void (*reset)(struct drm_encoder *encoder); /** * @destroy: * * Clean up encoder resources. This is only called at driver unload time * through drm_mode_config_cleanup() since an encoder cannot be * hotplugged in DRM. */ void (*destroy)(struct drm_encoder *encoder); /** * @late_register: * * This optional hook can be used to register additional userspace * interfaces attached to the encoder like debugfs interfaces. * It is called late in the driver load sequence from drm_dev_register(). * Everything added from this callback should be unregistered in * the early_unregister callback. * * Returns: * * 0 on success, or a negative error code on failure. */ int (*late_register)(struct drm_encoder *encoder); /** * @early_unregister: * * This optional hook should be used to unregister the additional * userspace interfaces attached to the encoder from * @late_register. It is called from drm_dev_unregister(), * early in the driver unload sequence to disable userspace access * before data structures are torndown. */ void (*early_unregister)(struct drm_encoder *encoder); }; - drm_encoder_helper_funcs :: struct drm_encoder_helper_funcs { /** * @dpms: * * Callback to control power levels on the encoder. If the mode passed in * is unsupported, the provider must use the next lowest power level. * This is used by the legacy encoder helpers to implement DPMS * functionality in drm_helper_connector_dpms(). * * This callback is also used to disable an encoder by calling it with * DRM_MODE_DPMS_OFF if the @disable hook isn't used. * * This callback is used by the legacy CRTC helpers. Atomic helpers * also support using this hook for enabling and disabling an encoder to * facilitate transitions to atomic, but it is deprecated. Instead * @enable and @disable should be used. */ void (*dpms)(struct drm_encoder *encoder, int mode); /** * @mode_valid: * * This callback is used to check if a specific mode is valid in this * encoder. This should be implemented if the encoder has some sort * of restriction in the modes it can display. For example, a given * encoder may be responsible to set a clock value. If the clock can * not produce all the values for the available modes then this callback * can be used to restrict the number of modes to only the ones that * can be displayed. * * This hook is used by the probe helpers to filter the mode list in * drm_helper_probe_single_connector_modes(), and it is used by the * atomic helpers to validate modes supplied by userspace in * drm_atomic_helper_check_modeset(). * * This function is optional. * * NOTE: * * Since this function is both called from the check phase of an atomic * commit, and the mode validation in the probe paths it is not allowed * to look at anything else but the passed-in mode, and validate it * against configuration-invariant hardward constraints. Any further * limits which depend upon the configuration can only be checked in * @mode_fixup or @atomic_check. * * RETURNS: * * drm_mode_status Enum */ enum drm_mode_status (*mode_valid)(struct drm_encoder *crtc, const struct drm_display_mode *mode); /** * @mode_fixup: * * This callback is used to validate and adjust a mode. The parameter * mode is the display mode that should be fed to the next element in * the display chain, either the final &drm_connector or a &drm_bridge. * The parameter adjusted_mode is the input mode the encoder requires. It * can be modified by this callback and does not need to match mode. See * also &drm_crtc_state.adjusted_mode for more details. * * This function is used by both legacy CRTC helpers and atomic helpers. * This hook is optional. * * NOTE: * * This function is called in the check phase of atomic modesets, which * can be aborted for any reason (including on userspace's request to * just check whether a configuration would be possible). Atomic drivers * MUST NOT touch any persistent state (hardware or software) or data * structures except the passed in adjusted_mode parameter. * * This is in contrast to the legacy CRTC helpers where this was * allowed. * * Atomic drivers which need to inspect and adjust more state should * instead use the @atomic_check callback. If @atomic_check is used, * this hook isn't called since @atomic_check allows a strict superset * of the functionality of @mode_fixup. * * Also beware that userspace can request its own custom modes, neither * core nor helpers filter modes to the list of probe modes reported by * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure * that modes are filtered consistently put any encoder constraints and * limits checks into @mode_valid. * * RETURNS: * * True if an acceptable configuration is possible, false if the modeset * operation should be rejected. */ bool (*mode_fixup)(struct drm_encoder *encoder, const struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode); /** * @prepare: * * This callback should prepare the encoder for a subsequent modeset, * which in practice means the driver should disable the encoder if it * is running. Most drivers ended up implementing this by calling their * @dpms hook with DRM_MODE_DPMS_OFF. * * This callback is used by the legacy CRTC helpers. Atomic helpers * also support using this hook for disabling an encoder to facilitate * transitions to atomic, but it is deprecated. Instead @disable should * be used. */ void (*prepare)(struct drm_encoder *encoder); /** * @commit: * * This callback should commit the new mode on the encoder after a modeset, * which in practice means the driver should enable the encoder. Most * drivers ended up implementing this by calling their @dpms hook with * DRM_MODE_DPMS_ON. * * This callback is used by the legacy CRTC helpers. Atomic helpers * also support using this hook for enabling an encoder to facilitate * transitions to atomic, but it is deprecated. Instead @enable should * be used. */ void (*commit)(struct drm_encoder *encoder); /** * @mode_set: * * This callback is used to update the display mode of an encoder. * * Note that the display pipe is completely off when this function is * called. Drivers which need hardware to be running before they program * the new display mode (because they implement runtime PM) should not * use this hook, because the helper library calls it only once and not * every time the display pipeline is suspend using either DPMS or the * new "ACTIVE" property. Such drivers should instead move all their * encoder setup into the @enable callback. * * This callback is used both by the legacy CRTC helpers and the atomic * modeset helpers. It is optional in the atomic helpers. * * NOTE: * * If the driver uses the atomic modeset helpers and needs to inspect * the connector state or connector display info during mode setting, * @atomic_mode_set can be used instead. */ void (*mode_set)(struct drm_encoder *encoder, struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode); /** * @atomic_mode_set: * * This callback is used to update the display mode of an encoder. * * Note that the display pipe is completely off when this function is * called. Drivers which need hardware to be running before they program * the new display mode (because they implement runtime PM) should not * use this hook, because the helper library calls it only once and not * every time the display pipeline is suspended using either DPMS or the * new "ACTIVE" property. Such drivers should instead move all their * encoder setup into the @enable callback. * * This callback is used by the atomic modeset helpers in place of the * @mode_set callback, if set by the driver. It is optional and should * be used instead of @mode_set if the driver needs to inspect the * connector state or display info, since there is no direct way to * go from the encoder to the current connector. */ void (*atomic_mode_set)(struct drm_encoder *encoder, struct drm_crtc_state *crtc_state, struct drm_connector_state *conn_state); /** * @get_crtc: * * This callback is used by the legacy CRTC helpers to work around * deficiencies in its own book-keeping. * * Do not use, use atomic helpers instead, which get the book keeping * right. * * FIXME: * * Currently only nouveau is using this, and as soon as nouveau is * atomic we can ditch this hook. */ struct drm_crtc *(*get_crtc)(struct drm_encoder *encoder); /** * @detect: * * This callback can be used by drivers who want to do detection on the * encoder object instead of in connector functions. * * It is not used by any helper and therefore has purely driver-specific * semantics. New drivers shouldn't use this and instead just implement * their own private callbacks. * * FIXME: * * This should just be converted into a pile of driver vfuncs. * Currently radeon, amdgpu and nouveau are using it. */ enum drm_connector_status (*detect)(struct drm_encoder *encoder, struct drm_connector *connector); /** * @atomic_disable: * * This callback should be used to disable the encoder. With the atomic * drivers it is called before this encoder's CRTC has been shut off * using their own &drm_crtc_helper_funcs.atomic_disable hook. If that * sequence is too simple drivers can just add their own driver private * encoder hooks and call them from CRTC's callback by looping over all * encoders connected to it using for_each_encoder_on_crtc(). * * This callback is a variant of @disable that provides the atomic state * to the driver. If @atomic_disable is implemented, @disable is not * called by the helpers. * * This hook is only used by atomic helpers. Atomic drivers don't need * to implement it if there's no need to disable anything at the encoder * level. To ensure that runtime PM handling (using either DPMS or the * new "ACTIVE" property) works @atomic_disable must be the inverse of * @atomic_enable. */ void (*atomic_disable)(struct drm_encoder *encoder, struct drm_atomic_state *state); /** * @atomic_enable: * * This callback should be used to enable the encoder. It is called * after this encoder's CRTC has been enabled using their own * &drm_crtc_helper_funcs.atomic_enable hook. If that sequence is * too simple drivers can just add their own driver private encoder * hooks and call them from CRTC's callback by looping over all encoders * connected to it using for_each_encoder_on_crtc(). * * This callback is a variant of @enable that provides the atomic state * to the driver. If @atomic_enable is implemented, @enable is not * called by the helpers. * * This hook is only used by atomic helpers, it is the opposite of * @atomic_disable. Atomic drivers don't need to implement it if there's * no need to enable anything at the encoder level. To ensure that * runtime PM handling works @atomic_enable must be the inverse of * @atomic_disable. */ void (*atomic_enable)(struct drm_encoder *encoder, struct drm_atomic_state *state); /** * @disable: * * This callback should be used to disable the encoder. With the atomic * drivers it is called before this encoder's CRTC has been shut off * using their own &drm_crtc_helper_funcs.disable hook. If that * sequence is too simple drivers can just add their own driver private * encoder hooks and call them from CRTC's callback by looping over all * encoders connected to it using for_each_encoder_on_crtc(). * * This hook is used both by legacy CRTC helpers and atomic helpers. * Atomic drivers don't need to implement it if there's no need to * disable anything at the encoder level. To ensure that runtime PM * handling (using either DPMS or the new "ACTIVE" property) works * @disable must be the inverse of @enable for atomic drivers. * * For atomic drivers also consider @atomic_disable and save yourself * from having to read the NOTE below! * * NOTE: * * With legacy CRTC helpers there's a big semantic difference between * @disable and other hooks (like @prepare or @dpms) used to shut down a * encoder: @disable is only called when also logically disabling the * display pipeline and needs to release any resources acquired in * @mode_set (like shared PLLs, or again release pinned framebuffers). * * Therefore @disable must be the inverse of @mode_set plus @commit for * drivers still using legacy CRTC helpers, which is different from the * rules under atomic. */ void (*disable)(struct drm_encoder *encoder); /** * @enable: * * This callback should be used to enable the encoder. With the atomic * drivers it is called after this encoder's CRTC has been enabled using * their own &drm_crtc_helper_funcs.enable hook. If that sequence is * too simple drivers can just add their own driver private encoder * hooks and call them from CRTC's callback by looping over all encoders * connected to it using for_each_encoder_on_crtc(). * * This hook is only used by atomic helpers, it is the opposite of * @disable. Atomic drivers don't need to implement it if there's no * need to enable anything at the encoder level. To ensure that * runtime PM handling (using either DPMS or the new "ACTIVE" property) * works @enable must be the inverse of @disable for atomic drivers. */ void (*enable)(struct drm_encoder *encoder); /** * @atomic_check: * * This callback is used to validate encoder state for atomic drivers. * Since the encoder is the object connecting the CRTC and connector it * gets passed both states, to be able to validate interactions and * update the CRTC to match what the encoder needs for the requested * connector. * * Since this provides a strict superset of the functionality of * @mode_fixup (the requested and adjusted modes are both available * through the passed in &struct drm_crtc_state) @mode_fixup is not * called when @atomic_check is implemented. * * This function is used by the atomic helpers, but it is optional. * * NOTE: * * This function is called in the check phase of an atomic update. The * driver is not allowed to change anything outside of the free-standing * state objects passed-in or assembled in the overall &drm_atomic_state * update tracking structure. * * Also beware that userspace can request its own custom modes, neither * core nor helpers filter modes to the list of probe modes reported by * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure * that modes are filtered consistently put any encoder constraints and * limits checks into @mode_valid. * * RETURNS: * * 0 on success, -EINVAL if the state or the transition can't be * supported, -ENOMEM on memory allocation failure and -EDEADLK if an * attempt to obtain another state object ran into a &drm_modeset_lock * deadlock. */ int (*atomic_check)(struct drm_encoder *encoder, struct drm_crtc_state *crtc_state, struct drm_connector_state *conn_state); }; drm_encoder_init -------------------- :: int drm_encoder_init(struct drm_device *dev, struct drm_encoder *encoder, const struct drm_encoder_funcs *funcs, int encoder_type, const char *name, ...) { int ret; /* encoder index is used with 32bit bitmasks */ if (WARN_ON(dev->mode_config.num_encoder >= 32)) return -EINVAL; //与connector类似，生成一个类型为DRM_MODE_OBJECT_ENCODER的struct drm_mode_object结构体 ret = drm_mode_object_add(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER); if (ret) return ret; //初始化encoder成员变量 encoder->dev = dev; encoder->encoder_type = encoder_type; encoder->funcs = funcs; if (name) { va_list ap; va_start(ap, name); encoder->name = kvasprintf(GFP_KERNEL, name, ap); va_end(ap); } else { encoder->name = kasprintf(GFP_KERNEL, "%s-%d", drm_encoder_enum_list[encoder_type].name, encoder->base.id); } if (!encoder->name) { ret = -ENOMEM; goto out_put; } //将encoder加入到结构体struct drm_mode_config的encoder链表中 list_add_tail(&encoder->head, &dev->mode_config.encoder_list); encoder->index = dev->mode_config.num_encoder++; out_put: if (ret) drm_mode_object_unregister(dev, &encoder->base); return ret; } - drm_mode_getencoder :: int drm_mode_getencoder(struct drm_device *dev, void *data, struct drm_file *file_priv) { struct drm_mode_get_encoder *enc_resp = data; struct drm_encoder *encoder; struct drm_crtc *crtc; if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; //根据传入的id找到encoder encoder = drm_encoder_find(dev, file_priv, enc_resp->encoder_id); if (!encoder) return -ENOENT; drm_modeset_lock(&dev->mode_config.connection_mutex, NULL); //找到encoder适配的crtc crtc = drm_encoder_get_crtc(encoder); if (crtc && drm_lease_held(file_priv, crtc->base.id)) enc_resp->crtc_id = crtc->base.id; else enc_resp->crtc_id = 0; drm_modeset_unlock(&dev->mode_config.connection_mutex); enc_resp->encoder_type = encoder->encoder_type; enc_resp->encoder_id = encoder->base.id; enc_resp->possible_crtcs = drm_lease_filter_crtcs(file_priv, encoder->possible_crtcs); enc_resp->possible_clones = encoder->possible_clones; return 0; } rcar_du_encoder_init ------------------------- :: //drivers/gpu/drm/rcar-du/rcar_du_encoder.c int rcar_du_encoder_init(struct rcar_du_device *rcdu, enum rcar_du_output output, struct device_node *enc_node) { struct rcar_du_encoder *renc; struct drm_encoder *encoder; struct drm_bridge *bridge; int ret; renc = devm_kzalloc(rcdu->dev, sizeof(*renc), GFP_KERNEL); if (renc == NULL) return -ENOMEM; rcdu->encoders[output] = renc; renc->output = output; encoder = rcar_encoder_to_drm_encoder(renc); dev_dbg(rcdu->dev, "initializing encoder %pOF for output %u\n", enc_node, output); /* * Locate the DRM bridge from the DT node. For the DPAD outputs, if the * DT node has a single port, assume that it describes a panel and * create a panel bridge. */ if ((output == RCAR_DU_OUTPUT_DPAD0 || output == RCAR_DU_OUTPUT_DPAD1) && rcar_du_encoder_count_ports(enc_node) == 1) { struct drm_panel *panel = of_drm_find_panel(enc_node); if (IS_ERR(panel)) { ret = PTR_ERR(panel); goto done; } bridge = devm_drm_panel_bridge_add(rcdu->dev, panel, DRM_MODE_CONNECTOR_DPI); if (IS_ERR(bridge)) { ret = PTR_ERR(bridge); goto done; } } else { bridge = of_drm_find_bridge(enc_node); if (!bridge) { if (output == RCAR_DU_OUTPUT_HDMI0 || output == RCAR_DU_OUTPUT_HDMI1) { #if IS_ENABLED(CONFIG_DRM_RCAR_DW_HDMI) ret = -EPROBE_DEFER; #else ret = 0; #endif goto done; } else if (output == RCAR_DU_OUTPUT_LVDS0 || output == RCAR_DU_OUTPUT_LVDS1) { #if IS_ENABLED(CONFIG_DRM_RCAR_LVDS) ret = -EPROBE_DEFER; #else ret = 0; #endif goto done; } else if (output == RCAR_DU_OUTPUT_MIPI_DSI0 || output == RCAR_DU_OUTPUT_MIPI_DSI1) { #if IS_ENABLED(CONFIG_DRM_RCAR_MIPI_DSI) ret = -EPROBE_DEFER; #else ret = 0; #endif goto done; } else { ret = -EPROBE_DEFER; goto done; } } if (output == RCAR_DU_OUTPUT_LVDS0 || output == RCAR_DU_OUTPUT_LVDS1) rcdu->lvds[output - RCAR_DU_OUTPUT_LVDS0] = bridge; } /* * On Gen3 skip the LVDS1 output if the LVDS1 encoder is used as a * companion for LVDS0 in dual-link mode. */ if (rcdu->info->gen >= 3 && output == RCAR_DU_OUTPUT_LVDS1) { if (rcar_lvds_dual_link(bridge)) { ret = -ENOLINK; goto done; } } renc->bridge = bridge; ret = drm_encoder_init(rcdu->ddev, encoder, &encoder_funcs, DRM_MODE_ENCODER_NONE, NULL); if (ret < 0) goto done; drm_encoder_helper_add(encoder, &encoder_helper_funcs); /* * Attach the bridge to the encoder. The bridge will create the * connector. */ ret = drm_bridge_attach(encoder, bridge, NULL); if (ret) { drm_encoder_cleanup(encoder); return ret; } done: if (ret < 0) { if (encoder->name) encoder->funcs->destroy(encoder); devm_kfree(rcdu->dev, renc); } return ret; } - 调用关系 :: rcar_du_probe |-- rcar_du_modeset_init |---|---drm_mode_config_init |---rcar_du_properties_init |---drm_vblank_init |---rcar_du_planes_init |---rcar_du_vsps_init |---rcar_du_crtc_create |---rcar_du_encoders_init | |---rcar_du_encoders_init_one | |---rcar_du_encoder_init |---rcar_du_writeback_init |---drm_dev_register |---drm_fbdev_generic_setup