connector代码分析 ======================= drm_connector结构体 --------------------- :: struct drm_connector { /** @dev: parent DRM device */ struct drm_device *dev; /** @kdev: kernel device for sysfs attributes */ struct device *kdev; /** @attr: sysfs attributes */ struct device_attribute *attr; /** * @head: * * List of all connectors on a @dev, linked from * &drm_mode_config.connector_list. Protected by * &drm_mode_config.connector_list_lock, but please only use * &drm_connector_list_iter to walk this list. */ struct list_head head; /** @base: base KMS object */ struct drm_mode_object base; /** @name: human readable name, can be overwritten by the driver */ char *name; /** * @mutex: Lock for general connector state, but currently only protects * @registered. Most of the connector state is still protected by * &drm_mode_config.mutex. */ struct mutex mutex; /** * @index: Compacted connector index, which matches the position inside * the mode_config.list for drivers not supporting hot-add/removing. Can * be used as an array index. It is invariant over the lifetime of the * connector. */ unsigned index; /** * @connector_type: * one of the DRM_MODE_CONNECTOR_ types from drm_mode.h */ int connector_type; /** @connector_type_id: index into connector type enum */ int connector_type_id; /** * @interlace_allowed: * Can this connector handle interlaced modes? Only used by * drm_helper_probe_single_connector_modes() for mode filtering. */ bool interlace_allowed; /** * @doublescan_allowed: * Can this connector handle doublescan? Only used by * drm_helper_probe_single_connector_modes() for mode filtering. */ bool doublescan_allowed; /** * @stereo_allowed: * Can this connector handle stereo modes? Only used by * drm_helper_probe_single_connector_modes() for mode filtering. */ bool stereo_allowed; /** * @ycbcr_420_allowed : This bool indicates if this connector is * capable of handling YCBCR 420 output. While parsing the EDID * blocks it's very helpful to know if the source is capable of * handling YCBCR 420 outputs. */ bool ycbcr_420_allowed; /** * @registration_state: Is this connector initializing, exposed * (registered) with userspace, or unregistered? * * Protected by @mutex. */ enum drm_connector_registration_state registration_state; /** * @modes: * Modes available on this connector (from fill_modes() + user). * Protected by &drm_mode_config.mutex. */ struct list_head modes; /** * @status: * One of the drm_connector_status enums (connected, not, or unknown). * Protected by &drm_mode_config.mutex. */ enum drm_connector_status status; /** * @probed_modes: * These are modes added by probing with DDC or the BIOS, before * filtering is applied. Used by the probe helpers. Protected by * &drm_mode_config.mutex. */ struct list_head probed_modes; /** * @display_info: Display information is filled from EDID information * when a display is detected. For non hot-pluggable displays such as * flat panels in embedded systems, the driver should initialize the * &drm_display_info.width_mm and &drm_display_info.height_mm fields * with the physical size of the display. * * Protected by &drm_mode_config.mutex. */ struct drm_display_info display_info; /** @funcs: connector control functions */ const struct drm_connector_funcs *funcs; /** * @edid_blob_ptr: DRM property containing EDID if present. Protected by * &drm_mode_config.mutex. This should be updated only by calling * drm_connector_update_edid_property(). */ struct drm_property_blob *edid_blob_ptr; /** @properties: property tracking for this connector */ struct drm_object_properties properties; /** * @scaling_mode_property: Optional atomic property to control the * upscaling. See drm_connector_attach_content_protection_property(). */ struct drm_property *scaling_mode_property; /** * @vrr_capable_property: Optional property to help userspace * query hardware support for variable refresh rate on a connector. * connector. Drivers can add the property to a connector by * calling drm_connector_attach_vrr_capable_property(). * * This should be updated only by calling * drm_connector_set_vrr_capable_property(). */ struct drm_property *vrr_capable_property; /** * @colorspace_property: Connector property to set the suitable * colorspace supported by the sink. */ struct drm_property *colorspace_property; /** * @path_blob_ptr: * * DRM blob property data for the DP MST path property. This should only * be updated by calling drm_connector_set_path_property(). */ struct drm_property_blob *path_blob_ptr; /** * @max_bpc_property: Default connector property for the max bpc to be * driven out of the connector. */ struct drm_property *max_bpc_property; #define DRM_CONNECTOR_POLL_HPD (1 << 0) #define DRM_CONNECTOR_POLL_CONNECT (1 << 1) #define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2) /** * @polled: * * Connector polling mode, a combination of * * DRM_CONNECTOR_POLL_HPD * The connector generates hotplug events and doesn't need to be * periodically polled. The CONNECT and DISCONNECT flags must not * be set together with the HPD flag. * * DRM_CONNECTOR_POLL_CONNECT * Periodically poll the connector for connection. * * DRM_CONNECTOR_POLL_DISCONNECT * Periodically poll the connector for disconnection, without * causing flickering even when the connector is in use. DACs should * rarely do this without a lot of testing. * * Set to 0 for connectors that don't support connection status * discovery. */ uint8_t polled; /** * @dpms: Current dpms state. For legacy drivers the * &drm_connector_funcs.dpms callback must update this. For atomic * drivers, this is handled by the core atomic code, and drivers must * only take &drm_crtc_state.active into account. */ int dpms; /** @helper_private: mid-layer private data */ const struct drm_connector_helper_funcs *helper_private; /** @cmdline_mode: mode line parsed from the kernel cmdline for this connector */ struct drm_cmdline_mode cmdline_mode; /** @force: a DRM_FORCE_ state for forced mode sets */ enum drm_connector_force force; /** @override_edid: has the EDID been overwritten through debugfs for testing? */ bool override_edid; #define DRM_CONNECTOR_MAX_ENCODER 3 /** * @encoder_ids: Valid encoders for this connector. Please only use * drm_connector_for_each_possible_encoder() to enumerate these. */ uint32_t encoder_ids[DRM_CONNECTOR_MAX_ENCODER]; /** * @encoder: Currently bound encoder driving this connector, if any. * Only really meaningful for non-atomic drivers. Atomic drivers should * instead look at &drm_connector_state.best_encoder, and in case they * need the CRTC driving this output, &drm_connector_state.crtc. */ struct drm_encoder *encoder; #define MAX_ELD_BYTES 128 /** @eld: EDID-like data, if present */ uint8_t eld[MAX_ELD_BYTES]; /** @latency_present: AV delay info from ELD, if found */ bool latency_present[2]; /** * @video_latency: Video latency info from ELD, if found. * [0]: progressive, [1]: interlaced */ int video_latency[2]; /** * @audio_latency: audio latency info from ELD, if found * [0]: progressive, [1]: interlaced */ int audio_latency[2]; /** * @ddc: associated ddc adapter. * A connector usually has its associated ddc adapter. If a driver uses * this field, then an appropriate symbolic link is created in connector * sysfs directory to make it easy for the user to tell which i2c * adapter is for a particular display. * * The field should be set by calling drm_connector_init_with_ddc(). */ struct i2c_adapter *ddc; /** * @null_edid_counter: track sinks that give us all zeros for the EDID. * Needed to workaround some HW bugs where we get all 0s */ int null_edid_counter; /** @bad_edid_counter: track sinks that give us an EDID with invalid checksum */ unsigned bad_edid_counter; /** * @edid_corrupt: Indicates whether the last read EDID was corrupt. Used * in Displayport compliance testing - Displayport Link CTS Core 1.2 * rev1.1 4.2.2.6 */ bool edid_corrupt; /** @debugfs_entry: debugfs directory for this connector */ struct dentry *debugfs_entry; /** * @state: * * Current atomic state for this connector. * * This is protected by &drm_mode_config.connection_mutex. Note that * nonblocking atomic commits access the current connector state without * taking locks. Either by going through the &struct drm_atomic_state * pointers, see for_each_oldnew_connector_in_state(), * for_each_old_connector_in_state() and * for_each_new_connector_in_state(). Or through careful ordering of * atomic commit operations as implemented in the atomic helpers, see * &struct drm_crtc_commit. */ struct drm_connector_state *state; /* DisplayID bits. FIXME: Extract into a substruct? */ /** * @tile_blob_ptr: * * DRM blob property data for the tile property (used mostly by DP MST). * This is meant for screens which are driven through separate display * pipelines represented by &drm_crtc, which might not be running with * genlocked clocks. For tiled panels which are genlocked, like * dual-link LVDS or dual-link DSI, the driver should try to not expose * the tiling and virtualize both &drm_crtc and &drm_plane if needed. * * This should only be updated by calling * drm_connector_set_tile_property(). */ struct drm_property_blob *tile_blob_ptr; /** @has_tile: is this connector connected to a tiled monitor */ bool has_tile; /** @tile_group: tile group for the connected monitor */ struct drm_tile_group *tile_group; /** @tile_is_single_monitor: whether the tile is one monitor housing */ bool tile_is_single_monitor; /** @num_h_tile: number of horizontal tiles in the tile group */ /** @num_v_tile: number of vertical tiles in the tile group */ uint8_t num_h_tile, num_v_tile; /** @tile_h_loc: horizontal location of this tile */ /** @tile_v_loc: vertical location of this tile */ uint8_t tile_h_loc, tile_v_loc; /** @tile_h_size: horizontal size of this tile. */ /** @tile_v_size: vertical size of this tile. */ uint16_t tile_h_size, tile_v_size; /** * @free_node: * * List used only by &drm_connector_list_iter to be able to clean up a * connector from any context, in conjunction with * &drm_mode_config.connector_free_work. */ struct llist_node free_node; /** @hdr_sink_metadata: HDR Metadata Information read from sink */ struct hdr_sink_metadata hdr_sink_metadata; }; drm_connector的主要初始化接口为 ``drm_connector_init`` - drm_connector_init :: int drm_connector_init(struct drm_device *dev, struct drm_connector *connector, const struct drm_connector_funcs *funcs, int connector_type) { //获取drm_mode_config结构体，一个drm设备只有一个struct drm_mode_config结构体 //里面配置了一些参数 struct drm_mode_config *config = &dev->mode_config; int ret; //获取connector_ida，后面会分配 struct ida *connector_ida = &drm_connector_enum_list[connector_type].ida; WARN_ON(drm_drv_uses_atomic_modeset(dev) && (!funcs->atomic_destroy_state || !funcs->atomic_duplicate_state)); //生成类型为DRM_MODE_OBJECT_CONNECTOR的struct drm_mode_object结构体 //connector->base.id会在用户态接口drmModeGetResources调用时，作为connector_id返回用户态 //后续用户态可以通过connector_id，调用drmModeGetConnector找到drm_connector，并获取相关参数 ret = __drm_mode_object_add(dev, &connector->base, DRM_MODE_OBJECT_CONNECTOR, false, drm_connector_free); if (ret) return ret; //得到properties connector->base.properties = &connector->properties; connector->dev = dev; connector->funcs = funcs; //生成drm_mode_config的connector_ida并作为该connector的index索引 /* connector index is used with 32bit bitmasks */ ret = ida_simple_get(&config->connector_ida, 0, 32, GFP_KERNEL); if (ret < 0) { DRM_DEBUG_KMS("Failed to allocate %s connector index: %d\n", drm_connector_enum_list[connector_type].name, ret); goto out_put; } connector->index = ret; ret = 0; //生成该connector的type的connector_ida connector->connector_type = connector_type; connector->connector_type_id = ida_simple_get(connector_ida, 1, 0, GFP_KERNEL); if (connector->connector_type_id < 0) { ret = connector->connector_type_id; goto out_put_id; } //初始化connector名称及链表，mutex等 connector->name = kasprintf(GFP_KERNEL, "%s-%d", drm_connector_enum_list[connector_type].name, connector->connector_type_id); if (!connector->name) { ret = -ENOMEM; goto out_put_type_id; } INIT_LIST_HEAD(&connector->probed_modes); INIT_LIST_HEAD(&connector->modes); mutex_init(&connector->mutex); connector->edid_blob_ptr = NULL; connector->tile_blob_ptr = NULL; connector->status = connector_status_unknown; connector->display_info.panel_orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN; drm_connector_get_cmdline_mode(connector); /* We should add connectors at the end to avoid upsetting the connector * index too much. */ spin_lock_irq(&config->connector_list_lock); list_add_tail(&connector->head, &config->connector_list); config->num_connector++; spin_unlock_irq(&config->connector_list_lock); if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL && connector_type != DRM_MODE_CONNECTOR_WRITEBACK) drm_connector_attach_edid_property(connector); drm_object_attach_property(&connector->base, config->dpms_property, 0); drm_object_attach_property(&connector->base, config->link_status_property, 0); drm_object_attach_property(&connector->base, config->non_desktop_property, 0); drm_object_attach_property(&connector->base, config->tile_property, 0); if (drm_core_check_feature(dev, DRIVER_ATOMIC)) { drm_object_attach_property(&connector->base, config->prop_crtc_id, 0); } connector->debugfs_entry = NULL; out_put_type_id: if (ret) ida_simple_remove(connector_ida, connector->connector_type_id); out_put_id: if (ret) ida_simple_remove(&config->connector_ida, connector->index); out_put: if (ret) drm_mode_object_unregister(dev, &connector->base); return ret; } 用户态操作 ----------------- - 用户态获取connector_id逻辑 :: //用户态 drmModeGetResources drmIoctl(fd, DRM_IOCTL_MODE_GETRESOURCES, &res) //res.crtc_id_ptr指向设备的所有crtc_id //内核态 DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETRESOURCES, drm_mode_getresources, 0) drm_mode_getresources drm_connector_list_iter_begin(dev, &conn_iter) drm_for_each_connector_iter(connector, &conn_iter) //遍历connector put_user(connector->base.id, connector_id + count) //拷贝id到用户态 drm_connector_list_iter_end(&conn_iter) - 用户态根据connector_id获取drm_connector :: //用户态 drmModeGetConnector() conn.connector_id = connector_id drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, &conn) //内核态 DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCONNECTOR, drm_mode_getconnector, 0) drm_mode_getconnector connector = drm_connector_lookup(dev, file_priv, out_resp->connector_id) //根据用户态传进来的id和type mo = drm_mode_object_find(dev, file_priv, id, DRM_MODE_OBJECT_CONNECTOR) return obj_to_connector(mo) - base.properties 记录connector的属性(如CRTC_ID/EDID/等),这些属性首先在drm_mode_create_standard_properties创建初始化并保存在 dev->mode_config中 :: //以CRTC_ID属性为例 drm_mode_config_init drmm_mode_config_init drm_mode_create_standard_properties //创建名称为DRTC_ID的属性 prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC, "CRTC_ID", DRM_MDOE_OBJECT_CRTC) //创建属性 drm_property_create //将该property保存在mode_config的property_list链表 list_add_tail(&property->head, &dev->mode_config.property_list) //保存到mode_config.prop_crtc_id中 dev->mode_config.prop_crtc_id = prop - properties的获取 :: //用户态 drmModeObjectGetProperties //通过connector_id以及DRM_MODE_OBJECT_CONNECTOR获取其属性 drmIoctl(fd, DRM_IOCTL_MODE_OBJ_GETPROPERTIES, &properties) //内核态 DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_GETPROPERTIES, drm_mode_obj_get_properties_ioctl, 0) //根据obj_id(connector_id)和obj_type(DRM_MODE_OBJECT_CONNECTOR)获取connector的drm_mode_object实例obj obj = drm_mode_object_find(dev, file_priv, arg->obj_id, arg->obj_type) //遍历connector->base.properties并拷贝到用户态 //这里仅拷贝了properties的id和value，并没有拷贝名称 drm_mode_object_get_properties(obj, file_priv->atomic, arg->props_ptr, arg->prop_values_ptr, ...) //上述获取的是connector的所有属性id, value, 如果要获取特定名称的属性，还需如下操作 //用户态 drmModeGetProperty drmIoctl(fd, DRM_IOCTL_MODE_GETPROPERTY, &prop) //内核态 DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPERTY, drm_mode_getproperty_ioctl, 0) connector初始化 ------------------- 以下代码基于renesas rcar平台分析 :: //rcar-du/rcar_lvds.c static int rcar_lvds_attach(struct drm_bridge *bridge) { struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge); struct drm_connector *connector = &lvds->connector; struct drm_encoder *encoder = bridge->encoder; int ret; /* If we have a next bridge just attach it. */ if (lvds->next_bridge) return drm_bridge_attach(bridge->encoder, lvds->next_bridge, bridge); /* Otherwise if we have a panel, create a connector. */ if (!lvds->panel) return 0; ret = drm_connector_init(bridge->dev, connector, &rcar_lvds_conn_funcs, DRM_MODE_CONNECTOR_LVDS); if (ret < 0) return ret; drm_connector_helper_add(connector, &rcar_lvds_conn_helper_funcs); ret = drm_connector_attach_encoder(connector, encoder); if (ret < 0) return ret; return drm_panel_attach(lvds->panel, connector); } static const struct drm_bridge_funcs rcar_lvds_bridge_ops = { .attach = rcar_lvds_attach, .detach = rcar_lvds_detach, .enable = rcar_lvds_enable, .disable = rcar_lvds_disable, .mode_fixup = rcar_lvds_mode_fixup, .mode_set = rcar_lvds_mode_set, }; static int rcar_lvds_probe(struct platform_device *pdev) { const struct soc_device_attribute *attr; struct rcar_lvds *lvds; struct resource *mem; int ret; lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL); if (lvds == NULL) return -ENOMEM; platform_set_drvdata(pdev, lvds); lvds->dev = &pdev->dev; lvds->info = of_device_get_match_data(&pdev->dev); attr = soc_device_match(lvds_quirk_matches); if (attr) lvds->info = attr->data; ret = rcar_lvds_parse_dt(lvds); if (ret < 0) return ret; lvds->bridge.driver_private = lvds; lvds->bridge.funcs = &rcar_lvds_bridge_ops; lvds->bridge.of_node = pdev->dev.of_node; mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); lvds->mmio = devm_ioremap_resource(&pdev->dev, mem); if (IS_ERR(lvds->mmio)) return PTR_ERR(lvds->mmio); ret = rcar_lvds_get_clocks(lvds); if (ret < 0) return ret; lvds->rstc = devm_reset_control_get(&pdev->dev, NULL); if (IS_ERR(lvds->rstc)) { dev_err(&pdev->dev, "failed to get cpg reset\n"); return PTR_ERR(lvds->rstc); } drm_bridge_add(&lvds->bridge); return 0; } static struct platform_driver rcar_lvds_platform_driver = { .probe = rcar_lvds_probe, .remove = rcar_lvds_remove, .driver = { .name = "rcar-lvds", .of_match_table = rcar_lvds_of_table, }, };