linux下无线鼠标驱动执行流程

浏览数：67 / 时间：2015年06月20日

操作系统： debian 7.4(linux 3.2.54）

硬件：一个无线鼠标、一个有线鼠标

从淘宝上花了15块钱买了个无线鼠标，很好奇它的驱动程序是如何执行的。

首先执行下面命令来捕获uevent事件：

sudo udevadm monitor

然后插入和移除再插入无线鼠标的nano接收器(为了完整的查看信息才操作这么多次)，可以在控制台下查看到下面的信息：

$ sudo udevadm monitor
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent
KERNEL[22375.667072] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1 (usb)
KERNEL[22375.667421] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0 (usb)
KERNEL[22375.667470] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0006 (hid)
KERNEL[22375.668613] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9 (input)
KERNEL[22375.668769] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9/mouse0 (input)
KERNEL[22375.668899] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9/event0 (input)
KERNEL[22375.669151] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0006/hidraw/hidraw0 (hidraw)
UDEV  [22375.693845] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1 (usb)
UDEV  [22375.701112] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0 (usb)
UDEV  [22375.714647] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9 (input)
UDEV  [22375.716553] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9/mouse0 (input)
UDEV  [22375.719153] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0006 (hid)
UDEV  [22375.719712] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0006/hidraw/hidraw0 (hidraw)
UDEV  [22375.729434] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9/event0 (input)
KERNEL[22456.752414] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9/mouse0 (input)
UDEV  [22456.752961] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9/mouse0 (input)
KERNEL[22456.776217] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9/event0 (input)
UDEV  [22456.776626] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9/event0 (input)
KERNEL[22456.785326] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9 (input)
KERNEL[22456.785501] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0006/hidraw/hidraw0 (hidraw)
KERNEL[22456.785523] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0006 (hid)
KERNEL[22456.785541] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0 (usb)
KERNEL[22456.785616] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1 (usb)
UDEV  [22456.786670] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9 (input)
UDEV  [22456.786699] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0006/hidraw/hidraw0 (hidraw)
UDEV  [22456.786842] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0006 (hid)
UDEV  [22456.786940] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0 (usb)
UDEV  [22456.794130] remove   /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1 (usb）
KERNEL[22562.038737] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1 (usb)
KERNEL[22562.039577] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0 (usb)
KERNEL[22562.039748] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0007 (hid)
KERNEL[22562.040809] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input10 (input)
KERNEL[22562.040953] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input10/mouse0 (input)
KERNEL[22562.041206] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input10/event0 (input)
KERNEL[22562.041400] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0007/hidraw/hidraw0 (hidraw)
UDEV  [22562.070879] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1 (usb)
UDEV  [22562.077647] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0 (usb)
UDEV  [22562.084927] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0007 (hid)
UDEV  [22562.086144] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/0003:1D57:0016.0007/hidraw/hidraw0 (hidraw)
UDEV  [22562.089305] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input10 (input)
UDEV  [22562.089350] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input10/mouse0 (input)
UDEV  [22562.089384] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input10/event0 (input)

输出信息中add对应行是插入时候产生的uevent,remove对应行是移除nano接收器时产生的uevent。

最后一次插入时在/sys文件夹下添加了很多目录，可以用下面命令查看：

$ cat /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input10/mouse0/device/id/vendor
1d57
$ cat /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input10/mouse0/device/id/product
0016

这与lsusb命令获取的信息一致：

$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 1a40:0101 Terminus Technology Inc. 4-Port HUB
Bus 001 Device 010: ID 1d57:0016 Xenta 
Bus 002 Device 002: ID 046d:c05a Logitech, Inc. Optical Mouse M90
Bus 003 Device 002: ID 413c:2003 Dell Computer Corp. Keyboard
Bus 001 Device 007: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)

$ lsusb -s 001:010 -v

Bus 001 Device 010: ID 1d57:0016 Xenta 
Couldn‘t open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x1d57 Xenta
  idProduct          0x0016 
  bcdDevice           11.10
  iManufacturer           1 
  iProduct                2 
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           34
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      2 Mouse
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.10
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      65
         Report Descriptors: 
           ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval               2

这个nano接收器的vendorID和productID分别是0x1d57和0x0016。

执行dmesg查看插入nano接收器的输入信息：

 dmesg | tail -n 15
[22375.556155] usb 1-1.1: new full-speed USB device number 9 using ehci_hcd
[22375.666762] usb 1-1.1: New USB device found, idVendor=1d57, idProduct=0016
[22375.666769] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[22375.666773] usb 1-1.1: Product: HID Wireless Mouse
[22375.666777] usb 1-1.1: Manufacturer: HID Wireless Mouse
[22375.668566] input: HID Wireless Mouse HID Wireless Mouse as /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input9
[22375.668979] generic-usb 0003:1D57:0016.0006: input,hidraw0: USB HID v1.10 Mouse [HID Wireless Mouse HID Wireless Mouse] on usb-0000:00:1d.7-1.1/input0
[22456.751805] usb 1-1.1: USB disconnect, device number 9
[22561.928127] usb 1-1.1: new full-speed USB device number 10 using ehci_hcd
[22562.038482] usb 1-1.1: New USB device found, idVendor=1d57, idProduct=0016
[22562.038489] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[22562.038493] usb 1-1.1: Product: HID Wireless Mouse
[22562.038497] usb 1-1.1: Manufacturer: HID Wireless Mouse
[22562.040767] input: HID Wireless Mouse HID Wireless Mouse as /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/1-1.1:1.0/input/input10
[22562.041276] generic-usb 0003:1D57:0016.0007: input,hidraw0: USB HID v1.10 Mouse [HID Wireless Mouse HID Wireless Mouse] on usb-0000:00:1d.7-1.1/input0

只有最后7行输出信息与最后一次插入nano接收器有关。

下面获取当前linux的内核源码，我使用的是debian 7.4,使用下面命令查看内核信息：

host@debian:~/soft/mini2440/linux-2.6.32.2$ uname -a
Linux debian 3.2.0-4-686-pae #1 SMP Debian 3.2.54-2 i686 GNU/Linux

当前内核版本是linux 3.2.54, 因为我已经下载了3.2.57的内核，就直接使用该版本的内核源代码（这两个版本源码差别很小，我只是查看源代码，所以就不想重新下载了）。

如果没有内核源代码，可以参考我的博文《编译debian内核》下载内核源码。

内核源代码下载后，执行解压缩，然后进入该文件夹.

鼠标属于hid(human interface device)，而nano接收器使用了usb口，所以其对应驱动所在位置很可能是在drivers/hid或者drivers/usb下。

为了确保能找到所有相关代码，我在drivers文件夹执行搜索：

$ find drivers/ -name ‘*.[ch]‘ -exec grep -rnHi ‘full-speed‘ {} \; | grep USB
drivers/usb/usb-common.c:23:        [USB_SPEED_FULL] = "full-speed",

可以看到该行源代码位于usb_speed_string。在vim下执行"make cscope"、"cs add cscope.out"、"cs f s usb_speed_string"可以搜索到所有使用usb_speed_string的代码。

其中最可能相关联的是hub_port_init函数中调用usb_speed_string的代码。

而hub_port_init又被hub_port_connect_change函数所调用。

当前情况下是将nano接收器插入到usb口，确实满足port连接状况改变的情况。

继续查找信息，使用下面命令：

$ find drivers/ -name ‘*.[ch]‘ -exec grep -rnHi ‘idVendor=‘ {} \;
drivers/usb/core/hub.c:1783:    dev_info(&udev->dev, "New USB device found, idVendor=%04x, idProduct=%04x\n",

该行代码位于annouce_device函数，annouce_device函数内容如下：

1 static void announce_device(struct usb_device *udev)
1782 {
1783     dev_info(&udev->dev, "New USB device found, idVendor=%04x, idProduct=%04x\n",
1784         le16_to_cpu(udev->descriptor.idVendor),
1785         le16_to_cpu(udev->descriptor.idProduct));
1786     dev_info(&udev->dev,
1787         "New USB device strings: Mfr=%d, Product=%d, SerialNumber=%d\n",
1788         udev->descriptor.iManufacturer,
1789         udev->descriptor.iProduct,
1790         udev->descriptor.iSerialNumber);
1791     show_string(udev, "Product", udev->product);
1792     show_string(udev, "Manufacturer", udev->manufacturer);
1793     show_string(udev, "SerialNumber", udev->serial);
1794 }

而annouce_device被usb_new_device调用，usb_new_device又被hub_port_connect_change函数所调用。

倒数第二行的输出信息中不容易用grep搜索到，直接搜索最后一行输出信息中的"generic-usb":

$ find drivers/ -name ‘*.[ch]‘ -exec grep -rnHi ‘generic-usb‘ {} \; 
drivers/hid/usbhid/hid-core.c:1477:    .name = "generic-usb",

这行输出信息很可能是初始化hid(对应于hid_init函数）时得到的输出信息。

稍微整理一下代码的执行流程（参考《essential linux device drivers》）。

usb代码架构中包含有三个重要的组成部分:usbcore, usb host controller driver, usb client driver.

其中usb host controller driver是比较靠近内核的一部分功能，此处不需要考虑。

usbcore中创建了一个khubd线程（位于usb_hub_init函数中）监控端口（port）的状态，当端口(port)状态改变时，会调用hub_port_connect_change函数。

hub_port_connect_change中调用hub_port_init对port进行初始化（包括获取设备描述符，这样能得到所有该设备相关信息），

然后调用usb_new_device调用device_add添加新的usb设备（此处即nano接收器）。

device_add添加该设备(nano接收器）时,主要是创建设备和sysfs文件夹以及添加相应的设备驱动,

中间经过漫长的调用（具体执行过程比较复杂，我还没有好好分析）后会执行hid_bus_match对总线匹配，

匹配成功后执行hid_device_probe->hid_hw_start->hid_connect输出信息。

我手中还有个有线鼠标，插入该鼠标得到的输出信息如下：

[ 7029.876038] usb 2-2: new low-speed USB device number 3 using uhci_hcd
[ 7030.051078] usb 2-2: New USB device found, idVendor=046d, idProduct=c05a
[ 7030.051085] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 7030.051090] usb 2-2: Product: USB Optical Mouse
[ 7030.051093] usb 2-2: Manufacturer: Logitech
[ 7030.067358] input: Logitech USB Optical Mouse as /devices/pci0000:00/0000:00:1d.0/usb2/2-2/2-2:1.0/input/input7
[ 7030.067521] generic-usb 0003:046D:C05A.0004: input,hidraw0: USB HID v1.11 Mouse [Logitech USB Optical Mouse] on usb-0000:00:1d.0-2/input0