linux设备驱动(26)usb驱动-基本数据和api
usb驱动目录drivers/usb/
usb/serial：usb 串行设备驱动 （例如usb 3G卡、蓝牙等）；
usb/storage：usb 大储量磁盘驱动（u盘）；
usb/host：usb host usb主机控制器驱动（嵌入式otg：dwc_otg）；
usb/core：usb 核心一些处理代码，所有的驱动相关处理都在这里，也都注册到它里面。
usb/usb-skeleton.c：经典的usb客户驱动框架，可以参考。
1 主要数据结构体
1.1 usb device设备结构体
定义位于：include\linux\usb.h
1 struct usb_device { 2 int devnum;//设备号，是在USB总线的地址 3 char devpath[16];//用于消息的设备ID字符串 4 u32 route; 5 enum usb_device_state state;//设备状态：已配置、未连接等 6 enum usb_device_speed speed; 7 8 struct usb_tt *tt;//处理传输者信息；用于低速、全速设备和高速HUB 9 int ttport;//位于tt HUB的设备口 10 11 unsigned int toggle[2];//每个端点的占一位，表明端点的方向([0] = IN, [1] = OUT) 12 13 struct usb_device *parent;//上一级HUB指针 14 struct usb_bus *bus;//总线指针 15 struct usb_host_endpoint ep0;//端点0数据 16 17 struct device dev;//一般的设备接口数据结构 18 19 struct usb_device_descriptor descriptor;//USB设备描述符 20 struct usb_host_bos *bos; 21 struct usb_host_config *config;//设备的所有配置结构体,配置结构体里包含了配置描述符 22 23 struct usb_host_config *actconfig;/被激活的设备配置 24 struct usb_host_endpoint *ep_in[16];//输入端点数组 25 struct usb_host_endpoint *ep_out[16];//输出端点数组 26 char **rawdescriptors;//每个配置的raw描述符 27 28 unsigned short bus_mA;//可使用的总线电流 29 u8 portnum;//父端口号 30 u8 level;//USB HUB的层数 31 32 unsigned can_submit:1;//URB可被提交标志 33 unsigned persist_enabled:1;//USB_PERSIST使能标志 34 unsigned have_langid:1;//string_langid存在标志 35 unsigned authorized:1; 36 unsigned authenticated:1; 37 unsigned wusb:1;//无线USB标志 38 unsigned lpm_capable:1; 39 unsigned usb2_hw_lpm_capable:1; 40 unsigned usb2_hw_lpm_enabled:1; 41 unsigned usb3_lpm_enabled:1; 42 int string_langid;//字符串语言ID 43 44 /* static strings from the device */设备的静态字符串 45 char *product;//产品名 46 char *manufacturer;//厂商名 47 char *serial;//产品串号 48 49 struct list_head filelist;//此设备打开的usbfs文件 50 51 int maxchild;//（若为HUB）接口数 52 53 u32 quirks; 54 atomic_t urbnum;//这个设备所提交的URB计数 55 56 unsigned long active_duration;//激活后使用计时 57 58 #ifdef CONFIG_PM //电源管理相关 59 unsigned long connect_time; 60 61 unsigned do_remote_wakeup:1; 62 unsigned reset_resume:1; 63 unsigned port_is_suspended:1; 64 #endif 65 struct wusb_dev *wusb_dev; 66 int slot_id; 67 enum usb_device_removable removable; 68 struct usb3_lpm_parameters u1_params; 69 struct usb3_lpm_parameters u2_params; 70 unsigned lpm_disable_count; 71 }
1.2 usb driver结构体
代表usb接口驱动
1 struct usb_driver { 2 const char *name; 3 4 int (*probe) (struct usb_interface *intf, 5 const struct usb_device_id *id); 6 7 void (*disconnect) (struct usb_interface *intf); 8 9 int (*unlocked_ioctl) (struct usb_interface *intf, unsigned int code, 10 void *buf); 11 12 int (*suspend) (struct usb_interface *intf, pm_message_t message); 13 int (*resume) (struct usb_interface *intf); 14 int (*reset_resume)(struct usb_interface *intf); 15 16 int (*pre_reset)(struct usb_interface *intf); 17 int (*post_reset)(struct usb_interface *intf); 18 19 const struct usb_device_id *id_table; 20 21 struct usb_dynids dynids; 22 struct usbdrv_wrap drvwrap; 23 unsigned int no_dynamic_id:1; 24 unsigned int supports_autosuspend:1; 25 unsigned int disable_hub_initiated_lpm:1; 26 unsigned int soft_unbind:1; 27 }
1.3 usb设备驱动
代表usb设备驱动
1 struct usb_device_driver { 2 const char *name; 3 4 int (*probe) (struct usb_device *udev); 5 void (*disconnect) (struct usb_device *udev); 6 7 int (*suspend) (struct usb_device *udev, pm_message_t message); 8 int (*resume) (struct usb_device *udev, pm_message_t message); 9 struct usbdrv_wrap drvwrap; 10 unsigned int supports_autosuspend:1; 11 }
1.4 usb bus结构体
代表usb总线 。
1 struct usb_bus { 2 struct device *controller; /* host/master side hardware */ 3 int busnum; /* Bus number (in order of reg) */ 4 const char *bus_name; /* stable id (PCI slot_name etc) */ 5 u8 uses_dma; /* Does the host controller use DMA? */ 6 u8 uses_pio_for_control; /* 7 * Does the host controller use PIO 8 * for control transfers? 9 */ 10 u8 otg_port; /* 0, or number of OTG/HNP port */ 11 unsigned is_b_host:1; /* true during some HNP roleswitches */ 12 unsigned b_hnp_enable:1; /* OTG: did A-Host enable HNP? */ 13 unsigned no_stop_on_short:1; /* 14 * Quirk: some controllers don't stop 15 * the ep queue on a short transfer 16 * with the URB_SHORT_NOT_OK flag set. 17 */ 18 unsigned sg_tablesize; /* 0 or largest number of sg list entries */ 19 20 int devnum_next; /* Next open device number in 21 * round-robin allocation */ 22 23 struct usb_devmap devmap; /* device address allocation map */ 24 struct usb_device *root_hub; /* Root hub */ 25 struct usb_bus *hs_companion; /* Companion EHCI bus, if any */ 26 struct list_head bus_list; /* list of busses */ 27 28 int bandwidth_allocated; /* on this bus: how much of the time 29 * reserved for periodic (intr/iso) 30 * requests is used, on average? 31 * Units: microseconds/frame. 32 * Limits: Full/low speed reserve 90%, 33 * while high speed reserves 80%. 34 */ 35 int bandwidth_int_reqs; /* number of Interrupt requests */ 36 int bandwidth_isoc_reqs; /* number of Isoc. requests */ 37 38 unsigned resuming_ports; /* bit array: resuming root-hub ports */ 39 40 #if defined(CONFIG_USB_MON) || defined(CONFIG_USB_MON_MODULE) 41 struct mon_bus *mon_bus; /* non-null when associated */ 42 int monitored; /* non-zero when monitored */ 43 #endif 44 }
1.4 usb_interface 结构体
1 struct usb_interface { 2 /* array of alternate settings for this interface, 3 * stored in no particular order */ 4 struct usb_host_interface *altsetting; 5 6 struct usb_host_interface *cur_altsetting; /* the currently //当前使用的设置，usb_host_interface中desc成员就是usb接口描述符 7 * active alternate setting */ 8 unsigned num_altsetting; /* number of alternate settings */可选的设置数量 9 10 /* If there is an interface association descriptor then it will list 11 * the associated interfaces */ 12 struct usb_interface_assoc_descriptor *intf_assoc; 13 14 int minor; /* minor number this interface is//如果绑定到这个接口的 USB 驱动使用 USB 主设备号, 这个变量包含由 USB 核心分配给接口的次设备号. 这只在一个成功的调用 usb_register_dev后才有效 15 * bound to */ 16 enum usb_interface_condition condition; /* state of binding */ 17 unsigned sysfs_files_created:1; /* the sysfs attributes exist */ 18 unsigned ep_devs_created:1; /* endpoint "devices" exist */ 19 unsigned unregistering:1; /* unregistration is in progress */ 20 unsigned needs_remote_wakeup:1; /* driver requires remote wakeup */ 21 unsigned needs_altsetting0:1; /* switch to altsetting 0 is pending */ 22 unsigned needs_binding:1; /* needs delayed unbind/rebind */ 23 unsigned reset_running:1; 24 unsigned resetting_device:1; /* true: bandwidth alloc after reset */ 25 26 struct device dev; /* interface specific device info */ 27 struct device *usb_dev; 28 atomic_t pm_usage_cnt; /* usage counter for autosuspend */ 29 struct work_struct reset_ws; /* for resets in atomic context */ 30 }
1.5 usb_host_interface 结构体
具体到接口描述符，它当然就是描述接口本身的信息的。一个接口可以有多个设置，使用不同的设置，描述接口的信息会有些不同，所以接口描述符并没有放在struct usb_interface结构里，而是放在表示接口设置的struct usb_host_interface结构里。
1 struct usb_host_interface { 2 struct usb_interface_descriptor desc;//usb接口描述符 3 4 int extralen; 5 unsigned char *extra; /* Extra descriptors */ 6 7 /* array of desc.bNumEndpoint endpoints associated with this 8 * interface setting. these will be in no particular order. 9 */ 10 struct usb_host_endpoint *endpoint;//这个设置所使用的端点 11 12 char *string; /* iInterface string, if present */ 13 }
1.6 usb配置结构体
1 struct usb_host_config { 2 struct usb_config_descriptor desc;//usb配置结构体 3 4 char *string; /* iConfiguration string, if present */ 5 6 /* List of any Interface Association Descriptors in this 7 * configuration. */ 8 struct usb_interface_assoc_descriptor *intf_assoc[USB_MAXIADS]; 9 10 /* the interfaces associated with this configuration, 11 * stored in no particular order */ 12 struct usb_interface *interface[USB_MAXINTERFACES];//配置所包含的接口，这个数组的顺序未必是按照配置里接口号的顺序 13 14 /* Interface information available even when this is not the 15 * active configuration */ 16 struct usb_interface_cache *intf_cache[USB_MAXINTERFACES];//usb接口的缓存 17 18 unsigned char *extra; /* Extra descriptors */ 19 int extralen; 20 }
1.7 usb端点结构体
1 struct usb_host_endpoint {
2 struct usb_endpoint_descriptor desc;//usb端点描述符
3 struct usb_ss_ep_comp_descriptor ss_ep_comp;
4 struct list_head urb_list;//端点要处理的urb队列.urb是usb通信的主角，设备中的每个端点都可以处理一个urb队列.要想和你的usb通信，就得创建一个urb，并且为它赋好值，交给咱们的usb core，它会找到合适的host controller，从而进行具体的数据传输。
5 void *hcpriv;//这是提供给HCD（host controller driver）用的
6 struct ep_device *ep_dev; /* For sysfs info */
7
8 unsigned char *extra; /* Extra descriptors */
9 int extralen;
10 int enabled;
11 };
2 主要api
2.1 usb设备驱动注册函数
1 int usb_register_device_driver(struct usb_device_driver *new_udriver, 2 struct module *owner) 3 { 4 int retval = 0; 5 6 if (usb_disabled()) 7 return -ENODEV; 8 9 new_udriver->drvwrap.for_devices = 1;//此值为1表示设备驱动 10 new_udriver->drvwrap.driver.name = (char *) new_udriver->name; 11 new_udriver->drvwrap.driver.bus = &usb_bus_type; 12 new_udriver->drvwrap.driver.probe = usb_probe_device; 13 new_udriver->drvwrap.driver.remove = usb_unbind_device; 14 new_udriver->drvwrap.driver.owner = owner; 15 16 retval = driver_register(&new_udriver->drvwrap.driver); 17 18 if (!retval) 19 pr_info("%s: registered new device driver %s\n", 20 usbcore_name, new_udriver->name); 21 else 22 printk(KERN_ERR "%s: error %d registering device " 23 " driver %s\n", 24 usbcore_name, retval, new_udriver->name); 25 26 return retval; 27 }
2.2 usb接口驱动注册函数
定义位于：include\linux\usb.h和drivers\usb\core\driver.c
1 /* use a define to avoid include chaining to get THIS_MODULE & friends */ 2 #define usb_register(driver) \ 3 usb_register_driver(driver, THIS_MODULE, KBUILD_MODNAME) 4 5 int usb_register_driver(struct usb_driver *new_driver, struct module *owner, 6 const char *mod_name) 7 { 8 int retval = 0; 9 10 if (usb_disabled()) 11 return -ENODEV; 12 13 new_driver->drvwrap.for_devices = 0;//此值为0表示接口驱动 14 new_driver->drvwrap.driver.name = (char *) new_driver->name; 15 new_driver->drvwrap.driver.bus = &usb_bus_type; 16 new_driver->drvwrap.driver.probe = usb_probe_interface; 17 new_driver->drvwrap.driver.remove = usb_unbind_interface; 18 new_driver->drvwrap.driver.owner = owner; 19 new_driver->drvwrap.driver.mod_name = mod_name; 20 spin_lock_init(&new_driver->dynids.lock); 21 INIT_LIST_HEAD(&new_driver->dynids.list); 22 23 retval = driver_register(&new_driver->drvwrap.driver);//注册usb接口驱动 24 if (retval) 25 goto out; 26 27 retval = usb_create_newid_files(new_driver); 28 if (retval) 29 goto out_newid; 30 31 pr_info("%s: registered new interface driver %s\n", 32 usbcore_name, new_driver->name); 33 34 out: 35 return retval; 36 37 out_newid: 38 driver_unregister(&new_driver->drvwrap.driver); 39 40 printk(KERN_ERR "%s: error %d registering interface " 41 " driver %s\n", 42 usbcore_name, retval, new_driver->name); 43 goto out; 44 }
2.3 usb设备分配函数
1 struct usb_device *usb_alloc_dev(struct usb_device *parent, 2 struct usb_bus *bus, unsigned port1) 3 { 4 struct usb_device *dev; 5 struct usb_hcd *usb_hcd = bus_to_hcd(bus); 6 unsigned root_hub = 0; 7 8 dev = kzalloc(sizeof(*dev), GFP_KERNEL);//分配usb设备 9 if (!dev) 10 return NULL; 11 12 if (!usb_get_hcd(usb_hcd)) { 13 kfree(dev); 14 return NULL; 15 } 16 /* Root hubs aren't true devices, so don't allocate HCD resources */ 17 if (usb_hcd->driver->alloc_dev && parent && 18 !usb_hcd->driver->alloc_dev(usb_hcd, dev)) { 19 usb_put_hcd(bus_to_hcd(bus)); 20 kfree(dev); 21 return NULL; 22 } 23 24 device_initialize(&dev->dev);//初始化usb设备 25 dev->dev.bus = &usb_bus_type;//指定usb总线 26 dev->dev.type = &usb_device_type; 27 dev->dev.groups = usb_device_groups; 28 dev->dev.dma_mask = bus->controller->dma_mask; 29 set_dev_node(&dev->dev, dev_to_node(bus->controller)); 30 dev->state = USB_STATE_ATTACHED; 31 dev->lpm_disable_count = 1; 32 atomic_set(&dev->urbnum, 0); 33 34 INIT_LIST_HEAD(&dev->ep0.urb_list); 35 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE; 36 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT; 37 /* ep0 maxpacket comes later, from device descriptor */ 38 usb_enable_endpoint(dev, &dev->ep0, false); 39 dev->can_submit = 1; 40 41 /* Save readable and stable topology id, distinguishing devices 42 * by location for diagnostics, tools, driver model, etc. The 43 * string is a path along hub ports, from the root. Each device's 44 * dev->devpath will be stable until USB is re-cabled, and hubs 45 * are often labeled with these port numbers. The name isn't 46 * as stable: bus->busnum changes easily from modprobe order, 47 * cardbus or pci hotplugging, and so on. 48 */ 49 if (unlikely(!parent)) { 50 dev->devpath[0] = '0'; 51 dev->route = 0; 52 53 dev->dev.parent = bus->controller; 54 dev_set_name(&dev->dev, "usb%d", bus->busnum); 55 root_hub = 1; 56 } else { 57 /* match any labeling on the hubs; it's one-based */ 58 if (parent->devpath[0] == '0') { 59 snprintf(dev->devpath, sizeof dev->devpath, 60 "%d", port1); 61 /* Root ports are not counted in route string */ 62 dev->route = 0; 63 } else { 64 snprintf(dev->devpath, sizeof dev->devpath, 65 "%s.%d", parent->devpath, port1); 66 /* Route string assumes hubs have less than 16 ports */ 67 if (port1 < 15) 68 dev->route = parent->route + 69 (port1 << ((parent->level - 1)*4)); 70 else 71 dev->route = parent->route + 72 (15 << ((parent->level - 1)*4)); 73 } 74 75 dev->dev.parent = &parent->dev; 76 dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);//设置usb设备名字 77 78 /* hub driver sets up TT records */ 79 } 80 81 dev->portnum = port1; 82 dev->bus = bus; 83 dev->parent = parent; 84 INIT_LIST_HEAD(&dev->filelist); 85 86 #ifdef CONFIG_PM 87 pm_runtime_set_autosuspend_delay(&dev->dev, 88 usb_autosuspend_delay * 1000); 89 dev->connect_time = jiffies; 90 dev->active_duration = -jiffies; 91 #endif 92 if (root_hub) /* Root hub always ok [and always wired] */ 93 dev->authorized = 1; 94 else { 95 dev->authorized = usb_hcd->authorized_default; 96 dev->wusb = usb_bus_is_wusb(bus)? 1 : 0; 97 } 98 return dev; 99 }
2.4 usb初始化函数
包括usb 总线的初始化，usb驱动的注册。usb_init 定义位于：drivers\usb\core\usb.c
1 static int __init usb_init(void) 2 { 3 int retval; 4 if (nousb) { 5 pr_info("%s: USB support disabled\n", usbcore_name); 6 return 0; 7 } 8 usb_init_pool_max(); 9 10 retval = usb_debugfs_init(); 11 if (retval) 12 goto out; 13 14 usb_acpi_register(); 15 retval = bus_register(&usb_bus_type);//usb总线注册 16 if (retval) 17 goto bus_register_failed; 18 retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb); 19 if (retval) 20 goto bus_notifier_failed; 21 retval = usb_major_init(); 22 if (retval) 23 goto major_init_failed; 24 retval = usb_register(&usbfs_driver);//usb接口驱动注册 25 if (retval) 26 goto driver_register_failed; 27 retval = usb_devio_init(); 28 if (retval) 29 goto usb_devio_init_failed; 30 retval = usb_hub_init(); 31 if (retval) 32 goto hub_init_failed; 33 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);//usb设备驱动的注册 34 if (!retval) 35 goto out; 36 37 usb_hub_cleanup(); 38 hub_init_failed: 39 usb_devio_cleanup(); 40 usb_devio_init_failed: 41 usb_deregister(&usbfs_driver); 42 driver_register_failed: 43 usb_major_cleanup(); 44 major_init_failed: 45 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb); 46 bus_notifier_failed: 47 bus_unregister(&usb_bus_type); 48 bus_register_failed: 49 usb_acpi_unregister(); 50 usb_debugfs_cleanup(); 51 out: 52 return retval; 53 }
usb总线的定义初始化，位于drivers\usb\core\driver.c：
1 struct bus_type usb_bus_type = { 2 .name = "usb", 3 .match = usb_device_match, 4 .uevent = usb_uevent, 5 };
2.5 usb设备和驱动的匹配
1 static int usb_device_match(struct device *dev, struct device_driver *drv) 2 { 3 /* devices and interfaces are handled separately */ 4 if (is_usb_device(dev)) { 5 6 /* interface drivers never match devices */ 7 if (!is_usb_device_driver(drv))//接口驱动不需要，只有设备驱动 8 return 0; 9 10 /* TODO: Add real matching code *///匹配code没有实现 11 return 1; 12 13 } else if (is_usb_interface(dev)) {//判断是接口驱动，以下是usb接口驱动的匹配 14 struct usb_interface *intf; 15 struct usb_driver *usb_drv; 16 const struct usb_device_id *id; 17 18 /* device drivers never match interfaces */ 19 if (is_usb_device_driver(drv)) 20 return 0; 21 22 intf = to_usb_interface(dev); 23 usb_drv = to_usb_driver(drv); 24 25 id = usb_match_id(intf, usb_drv->id_table);//匹配usb驱动成员 26 if (id) 27 return 1; 28 29 id = usb_match_dynamic_id(intf, usb_drv); 30 if (id) 31 return 1; 32 } 33 34 return 0; 35 }
USB驱动的id_table的结构体为usb_device_id定义：
1 struct usb_device_id { 2 3 __u16 match_flags; //与usb设备匹配那种类型？比较类型的宏如下: 4 //USB_DEVICE_ID_MATCH_INT_INFO : 用于匹配设备的接口描述符的3个成员 5 //USB_DEVICE_ID_MATCH_DEV_INFO: 用于匹配设备描述符的3个成员 6 //USB_DEVICE_ID_MATCH_DEVICE_AND_VERSION: 用于匹配特定的USB设备的4个成员 7 //USB_DEVICE_ID_MATCH_DEVICE:用于匹配特定的USB设备的2个成员(idVendor和idProduct) 8 9 10 /* 以下4个用匹配描述特定的USB设备 */ 11 __u16 idVendor; //厂家ID 12 __u16 idProduct; //产品ID 13 __u16 bcdDevice_lo; //设备的低版本号 14 __u16 bcdDevice_hi; //设备的高版本号 15 16 /*以下3个就是用于比较设备描述符的*/ 17 __u8 bDeviceClass; //设备类 18 __u8 bDeviceSubClass; //设备子类 19 __u8 bDeviceProtocol; //设备协议 20 21 /* 以下3个就是用于比较设备的接口描述符的 */ 22 __u8 bInterfaceClass; //接口类型 23 __u8 bInterfaceSubClass; //接口子类型 24 __u8 bInterfaceProtocol; //接口所遵循的协议 25 26 /* not matched against */ 27 kernel_ulong_t driver_info; 28 };
https://www.cnblogs.com/lifexy/p/7631900.html
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