USB裝置驅動_WDS
1. usb_alloc_dev中的 bus_type 中指定了匹配函式,和uevent中的環境引數。 ====>不同的bus_type的匹配函式可能是不同的,uevent的
環境變數引數也可能是不同的。
2. 推薦《LINUX核心原始碼情景分析》,裡面講USB控制器原始碼講解的非常清晰。
3.當USB裝置插入的時候會呼叫 usb_driver 的probe(),當USB裝置拔出的時候會呼叫 disconnect()函式,和其它非支援熱插拔的有些不
不同。所以usb_driver結構體裡面至少要初始化id_table,probe,disconnect.
4.一個邏輯裝置使用一個介面標識,比如音效卡有錄音和播放音樂的功能,因此有兩個介面,兩個驅動,分別負責錄音和播放。
5.寫驅動時先參考別人的,然後搞出一個最簡單的框架,然後在逐漸豐滿它。
6.唯一的dev->devnum用作了構建pipe的引數,應該可以使USB知道通過這個pipe的資料是發給哪個裝置的。
int pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);
/*1<<30|(dev->devnum << 8) | (endpoint << 15) | 0x80*/
#define usb_rcvintpipe(dev, endpoint) ((PIPE_INTERRUPT << 30) | __create_pipe(dev, endpoint) | USB_DIR_IN)
7.中斷傳輸是USB主機控制器不斷地查詢,然後有資料了USB主機控制器就中斷CPU,然後回撥urb完成回撥函式。回撥函式類似中斷服務函式
一樣被呼叫。
8.若不明白滑鼠資料的含義,可以先把資料打印出來,然後移動/點選滑鼠對比檢視資料的含義。
10.# cat /dev/tty1 用來檢視串列埠列印。
11.# hexdump /dev/input0 檢視裝置節點接收到的原始的資料,測試是OK的
12.目的:把一個USB滑鼠用作鍵盤,參考drivers/hid/usbhid/usbmouse.c
測試:
1.make menuconfig去掉之前的mouse驅動。若不去掉核心會匹配上它。
-> Device Drivers
-> HID Devices
<> USB Human Interface Device (full HID) support
2.載入自己的驅動,插拔USB滑鼠測試。
實驗原始碼:
/* * drivers\hid\usbhid\usbmouse.c */ #include <linux/kernel.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/init.h> #include <linux/usb/input.h> #include <linux/hid.h> static struct input_dev *uk_dev; static char *usb_buf; static dma_addr_t usb_buf_phys; static int len; static struct urb *uk_urb; static struct usb_device_id usbmouse_as_key_id_table [] = { { USB_INTERFACE_INFO(USB_INTERFACE_CLASS_HID, USB_INTERFACE_SUBCLASS_BOOT, USB_INTERFACE_PROTOCOL_MOUSE) }, //{USB_DEVICE(0x1234,0x5678)}, { } /* Terminating entry */ }; static void usbmouse_as_key_irq(struct urb *urb) { static unsigned char pre_val; #if 0 int i; static int cnt = 0; printk("data cnt %d: ", ++cnt); for (i = 0; i < len; i++) { printk("%02x ", usb_buf[i]); } printk("\n"); #endif /* USB滑鼠資料含義 * data[0]: bit0-左鍵, 1-按下, 0-鬆開 * bit1-右鍵, 1-按下, 0-鬆開 * bit2-中鍵, 1-按下, 0-鬆開 * */ if ((pre_val & (1<<0)) != (usb_buf[0] & (1<<0))) { /* 左鍵發生了變化 */ input_event(uk_dev, EV_KEY, KEY_L, (usb_buf[0] & (1<<0)) ? 1 : 0); input_sync(uk_dev); } if ((pre_val & (1<<1)) != (usb_buf[0] & (1<<1))) { /* 右鍵發生了變化 */ input_event(uk_dev, EV_KEY, KEY_S, (usb_buf[0] & (1<<1)) ? 1 : 0); input_sync(uk_dev); } if ((pre_val & (1<<2)) != (usb_buf[0] & (1<<2))) { /* 中鍵發生了變化 */ input_event(uk_dev, EV_KEY, KEY_ENTER, (usb_buf[0] & (1<<2)) ? 1 : 0); input_sync(uk_dev); } pre_val = usb_buf[0]; /* 重新提交urb */ usb_submit_urb(uk_urb, GFP_KERNEL); } static int usbmouse_as_key_probe(struct usb_interface *intf, const struct usb_device_id *id) { struct usb_device *dev = interface_to_usbdev(intf); struct usb_host_interface *interface; struct usb_endpoint_descriptor *endpoint; int pipe; interface = intf->cur_altsetting; endpoint = &interface->endpoint[0].desc; /* a. 分配一個input_dev */ uk_dev = input_allocate_device(); /* b. 設定 */ /* b.1 能產生哪類事件 */ set_bit(EV_KEY, uk_dev->evbit); set_bit(EV_REP, uk_dev->evbit); /* b.2 能產生哪些事件 */ set_bit(KEY_L, uk_dev->keybit); set_bit(KEY_S, uk_dev->keybit); set_bit(KEY_ENTER, uk_dev->keybit); /* c. 註冊 */ input_register_device(uk_dev); /* d. 硬體相關操作 */ /* 資料傳輸3要素: 源,目的,長度 */ /* 源: USB裝置的某個端點 */ pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress); /* 長度: */ len = endpoint->wMaxPacketSize; /* 目的: */ usb_buf = usb_buffer_alloc(dev, len, GFP_ATOMIC, &usb_buf_phys); /* 使用"3要素" */ /* 分配usb request block */ uk_urb = usb_alloc_urb(0, GFP_KERNEL); /* 使用"3要素設定urb" */ usb_fill_int_urb(uk_urb, dev, pipe, usb_buf, len, usbmouse_as_key_irq, NULL, endpoint->bInterval); uk_urb->transfer_dma = usb_buf_phys; uk_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP; /* 使用URB */ usb_submit_urb(uk_urb, GFP_KERNEL); return 0; } static void usbmouse_as_key_disconnect(struct usb_interface *intf) { struct usb_device *dev = interface_to_usbdev(intf); //printk("disconnect usbmouse!\n"); usb_kill_urb(uk_urb); usb_free_urb(uk_urb); usb_buffer_free(dev, len, usb_buf, usb_buf_phys); input_unregister_device(uk_dev); input_free_device(uk_dev); } /* 1. 分配/設定usb_driver */ static struct usb_driver usbmouse_as_key_driver = { .name = "usbmouse_as_key_", .probe = usbmouse_as_key_probe, .disconnect = usbmouse_as_key_disconnect, .id_table = usbmouse_as_key_id_table, }; static int usbmouse_as_key_init(void) { /* 2. 註冊 */ usb_register(&usbmouse_as_key_driver); return 0; } static void usbmouse_as_key_exit(void) { usb_deregister(&usbmouse_as_key_driver); } module_init(usbmouse_as_key_init); module_exit(usbmouse_as_key_exit); MODULE_LICENSE("GPL");
參考核心中的usbmouse.c:
#include <linux/kernel.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/init.h> #include <linux/usb/input.h> #include <linux/hid.h> /* for apple IDs */ #ifdef CONFIG_USB_HID_MODULE #include "../hid-ids.h" #endif /* * Version Information */ #define DRIVER_VERSION "v1.6" #define DRIVER_AUTHOR "Vojtech Pavlik <[email protected]>" #define DRIVER_DESC "USB HID Boot Protocol mouse driver" MODULE_AUTHOR(DRIVER_AUTHOR); MODULE_DESCRIPTION(DRIVER_DESC); MODULE_LICENSE("GPL"); struct usb_mouse { char name[128]; /*儲存的是dev->manufacturer*/ char phys[64]; struct usb_device *usbdev; struct input_dev *dev; struct urb *irq; /*中斷urb,也就是輪詢滑鼠*/ signed char *data; /*儲存DMA地址對應的虛擬地址*/ dma_addr_t data_dma; /*儲存DMA地址*/ }; static void usb_mouse_irq(struct urb *urb) { struct usb_mouse *mouse = urb->context; signed char *data = mouse->data; struct input_dev *dev = mouse->dev; int status; switch (urb->status) { case 0: /* success */ break; case -ECONNRESET: /* unlink */ case -ENOENT: case -ESHUTDOWN: return; /* -EPIPE: should clear the halt */ default: /* error */ goto resubmit; } /*是把所有的座標上報一遍,按下和鬆開App都可以監聽到了。若是沒有任 何改變的話這個完成函式應該不會被呼叫的*/ input_report_key(dev, BTN_LEFT, data[0] & 0x01); /*滑鼠左鍵*/ input_report_key(dev, BTN_RIGHT, data[0] & 0x02); /*滑鼠右鍵*/ input_report_key(dev, BTN_MIDDLE, data[0] & 0x04); /*滑鼠中鍵*/ input_report_key(dev, BTN_SIDE, data[0] & 0x08); input_report_key(dev, BTN_EXTRA, data[0] & 0x10); input_report_rel(dev, REL_X, data[1]); input_report_rel(dev, REL_Y, data[2]); input_report_rel(dev, REL_WHEEL, data[3]); input_sync(dev); resubmit: /*open 輸入裝置節點的時候submit一次,之後每次urb完成後都重複submit已保持 一致處於工作狀態*/ status = usb_submit_urb (urb, GFP_ATOMIC); if (status) dev_err(&mouse->usbdev->dev, "can't resubmit intr, %s-%s/input0, status %d\n", mouse->usbdev->bus->bus_name, mouse->usbdev->devpath, status); } static int usb_mouse_open(struct input_dev *dev) { struct usb_mouse *mouse = input_get_drvdata(dev); /*probe中set進去的*/ mouse->irq->dev = mouse->usbdev; if (usb_submit_urb(mouse->irq, GFP_KERNEL)) return -EIO; return 0; } static void usb_mouse_close(struct input_dev *dev) { struct usb_mouse *mouse = input_get_drvdata(dev); usb_kill_urb(mouse->irq); } static int usb_mouse_probe(struct usb_interface *intf, const struct usb_device_id *id) { /*通過介面獲取usb_device結構體*/ struct usb_device *dev = interface_to_usbdev(intf); struct usb_host_interface *interface; struct usb_endpoint_descriptor *endpoint; struct usb_mouse *mouse; struct input_dev *input_dev; int pipe, maxp; int error = -ENOMEM; /*獲取當前設定的這個介面的描述*/ interface = intf->cur_altsetting; /* the currently active alternate setting */ /*進一步判斷是不是滑鼠,這裡認為滑鼠只有1個IN端點的*/ if (interface->desc.bNumEndpoints != 1) return -ENODEV; endpoint = &interface->endpoint[0].desc; /*只有1個端點,所以只能是endpoint[0]*/ if (!usb_endpoint_is_int_in(endpoint)) /*進一步判斷是不是中斷輸入端點,無論是主從裝置的端點名都是以host為參考起方向名字的*/ return -ENODEV; pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress); maxp = usb_maxpacket(dev, pipe, usb_pipeout(pipe)); /*傳參(dev, pipe, 0),返回:epd->wMaxPacketSize & USB_ENDPOINT_MAXP_MASK;*/ /*構建usb滑鼠這個裝置*/ mouse = kzalloc(sizeof(struct usb_mouse), GFP_KERNEL); input_dev = input_allocate_device(); if (!mouse || !input_dev) goto fail1; /*mouse->data中儲存虛擬地址,mouse->data_dma儲存DMA地址*/ mouse->data = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &mouse->data_dma); if (!mouse->data) goto fail1; /*看來host是在輪詢滑鼠讀取滑鼠中的資料*/ mouse->irq = usb_alloc_urb(0, GFP_KERNEL); if (!mouse->irq) goto fail2; mouse->usbdev = dev; mouse->dev = input_dev; if (dev->manufacturer) strlcpy(mouse->name, dev->manufacturer, sizeof(mouse->name)); if (dev->product) { if (dev->manufacturer) strlcat(mouse->name, " ", sizeof(mouse->name)); /*加一個空格*/ strlcat(mouse->name, dev->product, sizeof(mouse->name)); } if (!strlen(mouse->name)) /*如果這個usb裝置沒有指定manufacturer和product字元使用VID PID作為名字*/ snprintf(mouse->name, sizeof(mouse->name), "USB HIDBP Mouse %04x:%04x", le16_to_cpu(dev->descriptor.idVendor), le16_to_cpu(dev->descriptor.idProduct)); usb_make_path(dev, mouse->phys, sizeof(mouse->phys)); strlcat(mouse->phys, "/input0", sizeof(mouse->phys)); input_dev->name = mouse->name; input_dev->phys = mouse->phys; usb_to_input_id(dev, &input_dev->id); input_dev->dev.parent = &intf->dev; /*構建裝置在裝置樹中的層次結構*/ input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL); /*對於滑鼠有按鍵和滾輪和相對位移,所以是這兩個*/ /*左鍵 中鍵 右鍵*/ input_dev->keybit[BIT_WORD(BTN_MOUSE)] = BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_RIGHT) | BIT_MASK(BTN_MIDDLE); /*只有x和y方向,沒有z的*/ input_dev->relbit[0] = BIT_MASK(REL_X) | BIT_MASK(REL_Y); /*這兩個是什麼意思 ???? */ input_dev->keybit[BIT_WORD(BTN_MOUSE)] |= BIT_MASK(BTN_SIDE) | BIT_MASK(BTN_EXTRA); input_dev->relbit[0] |= BIT_MASK(REL_WHEEL); input_set_drvdata(input_dev, mouse); /*所有的輸入裝置都必須要提供這兩個函式*/ input_dev->open = usb_mouse_open; /*裡面僅僅提交了一個urb*/ input_dev->close = usb_mouse_close; /*裡面只做了kill urb的操作*/ /*完成回撥函式usb_mouse_irq,當USB主機控制器收到資料後會產生一箇中斷,然後usb_mouse_irq會被呼叫*/ usb_fill_int_urb(mouse->irq, dev, pipe, mouse->data, (maxp > 8 ? 8 : maxp), usb_mouse_irq, mouse, endpoint->bInterval); /*endpoint->bInterval: 這裡查詢的頻率是由裝置自己決定的*/ mouse->irq->transfer_dma = mouse->data_dma; /*上面usb_fill_int_urb中的賦值是傳給不使用DMA的transfer_buffer的*/ mouse->irq->transfer_flags |= URB_NO_TRANSFER_DMA_MAP; /* urb->transfer_dma valid on submit */ error = input_register_device(mouse->dev); if (error) goto fail3; /*為了登出時使用mouse結構*/ usb_set_intfdata(intf, mouse); return 0; fail3: usb_free_urb(mouse->irq); fail2: usb_free_coherent(dev, 8, mouse->data, mouse->data_dma); fail1: input_free_device(input_dev); kfree(mouse); return error; } static void usb_mouse_disconnect(struct usb_interface *intf) { struct usb_mouse *mouse = usb_get_intfdata (intf); usb_set_intfdata(intf, NULL); if (mouse) { usb_kill_urb(mouse->irq); input_unregister_device(mouse->dev); usb_free_urb(mouse->irq); usb_free_coherent(interface_to_usbdev(intf), 8, mouse->data, mouse->data_dma); kfree(mouse); } } static const struct usb_device_id usb_mouse_id_table[] = { /*表示只要介面的class是hid,子class是boot,協議是mouse,都可以支援*/ { USB_INTERFACE_INFO(USB_INTERFACE_CLASS_HID, USB_INTERFACE_SUBCLASS_BOOT, USB_INTERFACE_PROTOCOL_MOUSE) }, { USB_DEVICE(0x1234, 0x5678) }, /*I add it, 表示只支援這一款裝置*/ { } /* Terminating entry */ }; MODULE_DEVICE_TABLE (usb, usb_mouse_id_table); static struct usb_driver usb_mouse_driver = { .name = "usbmouse", .probe = usb_mouse_probe, .disconnect = usb_mouse_disconnect, .id_table = usb_mouse_id_table, }; module_usb_driver(usb_mouse_driver)