USB设备驱动_WDS

/*
 * 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鼠标数据含义
     * data[0]: bit0-左键, 1-按下, 0-松开
     *          bit1-右键, 1-按下, 0-松开
     *          bit2-中键, 1-按下, 0-松开 
     *
     */
    if ((pre_val & (1<<0)) != (usb_buf[0] & (1<<0)))
    {
        /* 左键发生了变化 */
        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)))
    {
        /* 右键发生了变化 */
        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)))
    {
        /* 中键发生了变化 */
        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. 分配一个input_dev */
    uk_dev = input_allocate_device();
    
    /* b. 设置 */
    /* b.1 能产生哪类事件 */
    set_bit(EV_KEY, uk_dev->evbit);
    set_bit(EV_REP, uk_dev->evbit);
    
    /* b.2 能产生哪些事件 */
    set_bit(KEY_L, uk_dev->keybit);
    set_bit(KEY_S, uk_dev->keybit);
    set_bit(KEY_ENTER, uk_dev->keybit);
    
    /* c. 注册 */
    input_register_device(uk_dev);
    
    /* d. 硬件相关操作 */
    /* 数据传输3要素: 源,目的,长度 */
    /* 源: USB设备的某个端点 */
    pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);

    /* 长度: */
    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要素设置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/设置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. 注册 */
    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");

#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 <vojtech@ucw.cz>"
#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]; /*存储的是dev->manufacturer*/
    char phys[64];
    struct usb_device *usbdev;
    struct input_dev *dev;
    struct urb *irq; /*中断urb，也就是轮询鼠标*/

    signed char *data; /*存储DMA地址对应的虚拟地址*/
    dma_addr_t data_dma; /*存储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;
    }

    /*是把所有的坐标上报一遍，按下和松开App都可以监听到了。若是没有任
    何改变的话这个完成函数应该不会被调用的*/
    input_report_key(dev, BTN_LEFT,   data[0] & 0x01); /*鼠标左键*/
    input_report_key(dev, BTN_RIGHT,  data[0] & 0x02); /*鼠标右键*/
    input_report_key(dev, BTN_MIDDLE, data[0] & 0x04); /*鼠标中键*/
    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 输入设备节点的时候submit一次，之后每次urb完成后都重复submit已保持
    一致处于工作状态*/
    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进去的*/

    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)
{
    /*通过接口获取usb_device结构体*/
    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;

    /*获取当前设置的这个接口的描述*/
    interface = intf->cur_altsetting; /* the currently  active alternate setting */

    /*进一步判断是不是鼠标，这里认为鼠标只有1个IN端点的*/
    if (interface->desc.bNumEndpoints != 1)
        return -ENODEV;

    endpoint = &interface->endpoint[0].desc; /*只有1个端点，所以只能是endpoint[0]*/
    if (!usb_endpoint_is_int_in(endpoint)) /*进一步判断是不是中断输入端点,无论是主从设备的端点名都是以host为参考起方向名字的*/
        return -ENODEV;

    pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);
    maxp = usb_maxpacket(dev, pipe, usb_pipeout(pipe)); /*传参(dev, pipe, 0),返回:epd->wMaxPacketSize & USB_ENDPOINT_MAXP_MASK;*/

    /*构建usb鼠标这个设备*/
    mouse = kzalloc(sizeof(struct usb_mouse), GFP_KERNEL);
    input_dev = input_allocate_device();
    if (!mouse || !input_dev)
        goto fail1;

    /*mouse->data中存储虚拟地址，mouse->data_dma存储DMA地址*/
    mouse->data = usb_alloc_coherent(dev, 8, GFP_ATOMIC, &mouse->data_dma);
    if (!mouse->data)
        goto fail1;

    /*看来host是在轮询鼠标读取鼠标中的数据*/
    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)); /*加一个空格*/
        strlcat(mouse->name, dev->product, sizeof(mouse->name));
    }

    if (!strlen(mouse->name))  /*如果这个usb设备没有指定manufacturer和product字符使用VID PID作为名字*/
        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;  /*构建设备在设备树中的层次结构*/

    input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL); /*对于鼠标有按键和滚轮和相对位移，所以是这两个*/
    /*左键 中键 右键*/
    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，没有z的*/
    input_dev->relbit[0] = BIT_MASK(REL_X) | BIT_MASK(REL_Y);
    /*这两个是什么意思 ???? */
    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);

    /*所有的输入设备都必须要提供这两个函数*/
    input_dev->open = usb_mouse_open; /*里面仅仅提交了一个urb*/
    input_dev->close = usb_mouse_close; /*里面只做了kill urb的操作*/

    /*完成回调函数usb_mouse_irq,当USB主机控制器收到数据后会产生一个中断，然后usb_mouse_irq会被调用*/
    usb_fill_int_urb(mouse->irq, dev, pipe, mouse->data,
             (maxp > 8 ? 8 : maxp),
             usb_mouse_irq, mouse, endpoint->bInterval); /*endpoint->bInterval: 这里查询的频率是由设备自己决定的*/
    mouse->irq->transfer_dma = mouse->data_dma; /*上面usb_fill_int_urb中的赋值是传给不使用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;

    /*为了注销时使用mouse结构*/
    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[] = {
    /*表示只要接口的class是hid,子class是boot,协议是mouse，都可以支持*/
    { USB_INTERFACE_INFO(USB_INTERFACE_CLASS_HID, USB_INTERFACE_SUBCLASS_BOOT, USB_INTERFACE_PROTOCOL_MOUSE) },
    { USB_DEVICE(0x1234, 0x5678) }, /*I add it, 表示只支持这一款设备*/
    { }    /* 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)