2. 程式人生 > >V4L2攝像頭驅動移植

V4L2攝像頭驅動移植

阿新 • • 發佈：2019-01-15

攝像頭驅動原始碼路徑：/drivers/media/video/uvc/uvc_v4l2.c   

配置攝像v4l2驅動

make menuconfig
 Device Drivers  --->     
<*> Multimedia support  ---> 
<*>   Video For Linux  
[*]   Video capture adapters  --->  
[*]   V4L USB devices  --->  

<*>   USB Video Class (UVC) 

一般都符合UVC規範，不用修改原始碼，除非是自己定製的攝像頭驅動，自己購買cmos攝像頭，然後加上dsp處理圖片，壓縮成MJPEG格式，為了讓視訊更加流暢，這也只需要修改很小部分的程式碼。

自己寫V4L2驅動：myuvc.c

#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/videodev2.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>
#include <linux/mm.h>
#include <asm/atomic.h>
#include <asm/unaligned.h>

#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/videobuf-core.h>

#include "uvcvideo.h"

/* 參考 drivers/media/video/uvc */

#define MYUVC_URBS 5

/* Values for bmHeaderInfo (Video and Still Image Payload Headers, 2.4.3.3) */
#define UVC_STREAM_EOH	(1 << 7)
#define UVC_STREAM_ERR	(1 << 6)
#define UVC_STREAM_STI	(1 << 5)
#define UVC_STREAM_RES	(1 << 4)
#define UVC_STREAM_SCR	(1 << 3)
#define UVC_STREAM_PTS	(1 << 2)
#define UVC_STREAM_EOF	(1 << 1)
#define UVC_STREAM_FID	(1 << 0)


struct myuvc_streaming_control {
	__u16 bmHint;
	__u8  bFormatIndex;
	__u8  bFrameIndex;
	__u32 dwFrameInterval;
	__u16 wKeyFrameRate;
	__u16 wPFrameRate;
	__u16 wCompQuality;
	__u16 wCompWindowSize;
	__u16 wDelay;
	__u32 dwMaxVideoFrameSize;
	__u32 dwMaxPayloadTransferSize;
	__u32 dwClockFrequency;
	__u8  bmFramingInfo;
	__u8  bPreferedVersion;
	__u8  bMinVersion;
	__u8  bMaxVersion;
};



struct frame_desc {
    int width;
    int height;
};

/* 參考uvc_video_queue定義一些結構體 */
struct myuvc_buffer {    
    struct v4l2_buffer buf;
    int state;
    int vma_use_count; /* 表示是否已經被mmap */
    wait_queue_head_t wait;  /* APP要讀某個緩衝區,如果無資料,在此休眠 */
	struct list_head stream;
	struct list_head irq;    
};

struct myuvc_queue {
    void *mem;
    int count;
    int buf_size;    
    struct myuvc_buffer buffer[32];

	struct urb *urb[32];
	char *urb_buffer[32];
	dma_addr_t urb_dma[32];
	unsigned int urb_size;

	struct list_head mainqueue;   /* 供APP消費用 */
	struct list_head irqqueue;    /* 供底層驅動生產用 */
};

static struct myuvc_queue myuvc_queue;

static struct video_device *myuvc_vdev;
static struct usb_device *myuvc_udev;
static int myuvc_bEndpointAddress = 0x81;
static int myuvc_streaming_intf;
static int myuvc_control_intf;
static int myuvc_streaming_bAlternateSetting = 8;
static struct v4l2_format myuvc_format;

static struct frame_desc frames[] = {{640, 480}, {352, 288}, {320, 240}, {176, 144}, {160, 120}};
static int frame_idx = 1;
static int bBitsPerPixel = 16; /* lsusb -v -d 0x1e4e:  "bBitsPerPixel" */
static int uvc_version = 0x0100; /* lsusb -v -d 0x1e4e: bcdUVC */

static int wMaxPacketSize = 1024;
static int ProcessingUnitID = 3;

static struct myuvc_streaming_control myuvc_params;


/* A2 參考 uvc_v4l2_do_ioctl */
static int myuvc_vidioc_querycap(struct file *file, void  *priv,
					struct v4l2_capability *cap)
{    
    memset(cap, 0, sizeof *cap);
    strcpy(cap->driver, "myuvc");
    strcpy(cap->card, "myuvc");
    cap->version = 1;
    
    cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
 
	return 0;
}

/* A3 列舉支援哪種格式
 * 參考: uvc_fmts 陣列
 */
static int myuvc_vidioc_enum_fmt_vid_cap(struct file *file, void  *priv,
					struct v4l2_fmtdesc *f)
{
    /* 人工檢視描述符可知我們用的攝像頭只支援1種格式 */
	if (f->index >= 1)
		return -EINVAL;

    /* 支援什麼格式呢?
     * 檢視VideoStreaming Interface的描述符,
     * 得到GUID為"59 55 59 32 00 00 10 00 80 00 00 aa 00 38 9b 71"
     */
	strcpy(f->description, "4:2:2, packed, YUYV");
	f->pixelformat = V4L2_PIX_FMT_YUYV;    
    
	return 0;
}

/* A4 返回當前所使用的格式 */
static int myuvc_vidioc_g_fmt_vid_cap(struct file *file, void *priv,
					struct v4l2_format *f)
{
    memcpy(f, &myuvc_format, sizeof(myuvc_format));
	return (0);
}

/* A5 測試驅動程式是否支援某種格式, 強制設定該格式 
 * 參考: uvc_v4l2_try_format
 *       myvivi_vidioc_try_fmt_vid_cap
 */
static int myuvc_vidioc_try_fmt_vid_cap(struct file *file, void *priv,
			struct v4l2_format *f)
{
    if (f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
    {
        return -EINVAL;
    }

    if (f->fmt.pix.pixelformat != V4L2_PIX_FMT_YUYV)
        return -EINVAL;
    
    /* 調整format的width, height, 
     * 計算bytesperline, sizeimage
     */

    /* 人工檢視描述符, 確定支援哪幾種解析度 */
    f->fmt.pix.width  = frames[frame_idx].width;
    f->fmt.pix.height = frames[frame_idx].height;
    
	f->fmt.pix.bytesperline =
		(f->fmt.pix.width * bBitsPerPixel) >> 3;
	f->fmt.pix.sizeimage =
		f->fmt.pix.height * f->fmt.pix.bytesperline;
    
    return 0;
}

/* A6 參考 myvivi_vidioc_s_fmt_vid_cap */
static int myuvc_vidioc_s_fmt_vid_cap(struct file *file, void *priv,
					struct v4l2_format *f)
{
	int ret = myuvc_vidioc_try_fmt_vid_cap(file, NULL, f);
	if (ret < 0)
		return ret;

    memcpy(&myuvc_format, f, sizeof(myuvc_format));
    
    return 0;
}

static int myuvc_free_buffers(void)
{
    if (myuvc_queue.mem)
    {
        vfree(myuvc_queue.mem);
        memset(&myuvc_queue, 0, sizeof(myuvc_queue));
        myuvc_queue.mem = NULL;
    }
    return 0;
}

/* A7 APP呼叫該ioctl讓驅動程式分配若干個快取, APP將從這些快取中讀到視訊資料 
 * 參考: uvc_alloc_buffers
 */
static int myuvc_vidioc_reqbufs(struct file *file, void *priv,
			  struct v4l2_requestbuffers *p)
{
    int nbuffers = p->count;
    int bufsize  = PAGE_ALIGN(myuvc_format.fmt.pix.sizeimage);
    unsigned int i;
    void *mem = NULL;
    int ret;

    if ((ret = myuvc_free_buffers()) < 0)
        goto done;

    /* Bail out if no buffers should be allocated. */
    if (nbuffers == 0)
        goto done;

    /* Decrement the number of buffers until allocation succeeds. */
    for (; nbuffers > 0; --nbuffers) {
        mem = vmalloc_32(nbuffers * bufsize);
        if (mem != NULL)
            break;
    }

    if (mem == NULL) {
        ret = -ENOMEM;
        goto done;
    }

    /* 這些快取是一次性作為一個整體來分配的 */
    memset(&myuvc_queue, 0, sizeof(myuvc_queue));

	INIT_LIST_HEAD(&myuvc_queue.mainqueue);
	INIT_LIST_HEAD(&myuvc_queue.irqqueue);

    for (i = 0; i < nbuffers; ++i) {
        myuvc_queue.buffer[i].buf.index = i;
        myuvc_queue.buffer[i].buf.m.offset = i * bufsize;
        myuvc_queue.buffer[i].buf.length = myuvc_format.fmt.pix.sizeimage;
        myuvc_queue.buffer[i].buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        myuvc_queue.buffer[i].buf.sequence = 0;
        myuvc_queue.buffer[i].buf.field = V4L2_FIELD_NONE;
        myuvc_queue.buffer[i].buf.memory = V4L2_MEMORY_MMAP;
        myuvc_queue.buffer[i].buf.flags = 0;
        myuvc_queue.buffer[i].state     = VIDEOBUF_IDLE;
        init_waitqueue_head(&myuvc_queue.buffer[i].wait);
    }

    myuvc_queue.mem = mem;
    myuvc_queue.count = nbuffers;
    myuvc_queue.buf_size = bufsize;
    ret = nbuffers;

done:
    return ret;
}

/* A8 查詢快取狀態, 比如地址資訊(APP可以用mmap進行對映) 
 * 參考 uvc_query_buffer
 */
static int myuvc_vidioc_querybuf(struct file *file, void *priv, struct v4l2_buffer *v4l2_buf)
{
    int ret = 0;
    
	if (v4l2_buf->index >= myuvc_queue.count) {
		ret = -EINVAL;
		goto done;
	}

    memcpy(v4l2_buf, &myuvc_queue.buffer[v4l2_buf->index].buf, sizeof(*v4l2_buf));

    /* 更新flags */
	if (myuvc_queue.buffer[v4l2_buf->index].vma_use_count)
		v4l2_buf->flags |= V4L2_BUF_FLAG_MAPPED;


	switch (myuvc_queue.buffer[v4l2_buf->index].state) {
    	case VIDEOBUF_ERROR:
    	case VIDEOBUF_DONE:
    		v4l2_buf->flags |= V4L2_BUF_FLAG_DONE;
    		break;
    	case VIDEOBUF_QUEUED:
    	case VIDEOBUF_ACTIVE:
    		v4l2_buf->flags |= V4L2_BUF_FLAG_QUEUED;
    		break;
    	case VIDEOBUF_IDLE:
    	default:
    		break;
	}

done:    
	return ret;
}

/* A10 把緩衝區放入佇列, 底層的硬體操作函式將會把資料放入這個佇列的快取 
 * 參考: uvc_queue_buffer
 */
static int myuvc_vidioc_qbuf(struct file *file, void *priv, struct v4l2_buffer *v4l2_buf)
{
    struct myuvc_buffer *buf;

    /* 0. APP傳入的v4l2_buf可能有問題, 要做判斷 */

	if (v4l2_buf->type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
	    v4l2_buf->memory != V4L2_MEMORY_MMAP) {
		return -EINVAL;
	}

	if (v4l2_buf->index >= myuvc_queue.count) {
		return -EINVAL;
	}

    buf = &myuvc_queue.buffer[v4l2_buf->index];

	if (buf->state != VIDEOBUF_IDLE) {
		return -EINVAL;
	}


    /* 1. 修改狀態 */
	buf->state = VIDEOBUF_QUEUED;
	buf->buf.bytesused = 0;

    /* 2. 放入2個佇列 */
    /* 佇列1: 供APP使用 
     * 當緩衝區沒有資料時,放入mainqueue佇列
     * 當緩衝區有資料時, APP從mainqueue佇列中取出
     */
	list_add_tail(&buf->stream, &myuvc_queue.mainqueue);

    /* 佇列2: 供產生資料的函式使用
     * 當採集到資料時,從irqqueue佇列中取出第1個緩衝區,存入資料
     */
	list_add_tail(&buf->irq, &myuvc_queue.irqqueue);
    
	return 0;
}

static void myuvc_print_streaming_params(struct myuvc_streaming_control *ctrl)
{
    printk("video params:\n");
    printk("bmHint                   = %d\n", ctrl->bmHint);
    printk("bFormatIndex             = %d\n", ctrl->bFormatIndex);
    printk("bFrameIndex              = %d\n", ctrl->bFrameIndex);
    printk("dwFrameInterval          = %d\n", ctrl->dwFrameInterval);
    printk("wKeyFrameRate            = %d\n", ctrl->wKeyFrameRate);
    printk("wPFrameRate              = %d\n", ctrl->wPFrameRate);
    printk("wCompQuality             = %d\n", ctrl->wCompQuality);
    printk("wCompWindowSize          = %d\n", ctrl->wCompWindowSize);
    printk("wDelay                   = %d\n", ctrl->wDelay);
    printk("dwMaxVideoFrameSize      = %d\n", ctrl->dwMaxVideoFrameSize);
    printk("dwMaxPayloadTransferSize = %d\n", ctrl->dwMaxPayloadTransferSize);
    printk("dwClockFrequency         = %d\n", ctrl->dwClockFrequency);
    printk("bmFramingInfo            = %d\n", ctrl->bmFramingInfo);
    printk("bPreferedVersion         = %d\n", ctrl->bPreferedVersion);
    printk("bMinVersion              = %d\n", ctrl->bMinVersion);
    printk("bMinVersion              = %d\n", ctrl->bMinVersion);
}


/* 參考: uvc_get_video_ctrl 
 (ret = uvc_get_video_ctrl(video, probe, 1, GET_CUR)) 
 static int uvc_get_video_ctrl(struct uvc_video_device *video,
     struct uvc_streaming_control *ctrl, int probe, __u8 query)
 */
static int myuvc_get_streaming_params(struct myuvc_streaming_control *ctrl)
{
	__u8 *data;
	__u16 size;
	int ret;
	__u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
	unsigned int pipe;

	size = uvc_version >= 0x0110 ? 34 : 26;
	data = kmalloc(size, GFP_KERNEL);
	if (data == NULL)
		return -ENOMEM;
   
	pipe = (GET_CUR & 0x80) ? usb_rcvctrlpipe(myuvc_udev, 0)
			      : usb_sndctrlpipe(myuvc_udev, 0);
	type |= (GET_CUR & 0x80) ? USB_DIR_IN : USB_DIR_OUT;

	ret = usb_control_msg(myuvc_udev, pipe, GET_CUR, type, VS_PROBE_CONTROL << 8,
			0 << 8 | myuvc_streaming_intf, data, size, 5000);

    if (ret < 0)
        goto done;

	ctrl->bmHint = le16_to_cpup((__le16 *)&data[0]);
	ctrl->bFormatIndex = data[2];
	ctrl->bFrameIndex = data[3];
	ctrl->dwFrameInterval = le32_to_cpup((__le32 *)&data[4]);
	ctrl->wKeyFrameRate = le16_to_cpup((__le16 *)&data[8]);
	ctrl->wPFrameRate = le16_to_cpup((__le16 *)&data[10]);
	ctrl->wCompQuality = le16_to_cpup((__le16 *)&data[12]);
	ctrl->wCompWindowSize = le16_to_cpup((__le16 *)&data[14]);
	ctrl->wDelay = le16_to_cpup((__le16 *)&data[16]);
	ctrl->dwMaxVideoFrameSize = get_unaligned_le32(&data[18]);
	ctrl->dwMaxPayloadTransferSize = get_unaligned_le32(&data[22]);

	if (size == 34) {
		ctrl->dwClockFrequency = get_unaligned_le32(&data[26]);
		ctrl->bmFramingInfo = data[30];
		ctrl->bPreferedVersion = data[31];
		ctrl->bMinVersion = data[32];
		ctrl->bMaxVersion = data[33];
	} else {
		//ctrl->dwClockFrequency = video->dev->clock_frequency;
		ctrl->bmFramingInfo = 0;
		ctrl->bPreferedVersion = 0;
		ctrl->bMinVersion = 0;
		ctrl->bMaxVersion = 0;
	}

done:
    kfree(data);
    
    return (ret < 0) ? ret : 0;
}

/* 參考: uvc_v4l2_try_format ∕uvc_probe_video 
 *       uvc_set_video_ctrl(video, probe, 1)
 */
static int myuvc_try_streaming_params(struct myuvc_streaming_control *ctrl)
{
    __u8 *data;
    __u16 size;
    int ret;
	__u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
	unsigned int pipe;
    
	memset(ctrl, 0, sizeof *ctrl);
    
	ctrl->bmHint = 1;	/* dwFrameInterval */
	ctrl->bFormatIndex = 1;
	ctrl->bFrameIndex  = frame_idx + 1;
	ctrl->dwFrameInterval = 333333;


    size = uvc_version >= 0x0110 ? 34 : 26;
    data = kzalloc(size, GFP_KERNEL);
    if (data == NULL)
        return -ENOMEM;

    *(__le16 *)&data[0] = cpu_to_le16(ctrl->bmHint);
    data[2] = ctrl->bFormatIndex;
    data[3] = ctrl->bFrameIndex;
    *(__le32 *)&data[4] = cpu_to_le32(ctrl->dwFrameInterval);
    *(__le16 *)&data[8] = cpu_to_le16(ctrl->wKeyFrameRate);
    *(__le16 *)&data[10] = cpu_to_le16(ctrl->wPFrameRate);
    *(__le16 *)&data[12] = cpu_to_le16(ctrl->wCompQuality);
    *(__le16 *)&data[14] = cpu_to_le16(ctrl->wCompWindowSize);
    *(__le16 *)&data[16] = cpu_to_le16(ctrl->wDelay);
    put_unaligned_le32(ctrl->dwMaxVideoFrameSize, &data[18]);
    put_unaligned_le32(ctrl->dwMaxPayloadTransferSize, &data[22]);

    if (size == 34) {
        put_unaligned_le32(ctrl->dwClockFrequency, &data[26]);
        data[30] = ctrl->bmFramingInfo;
        data[31] = ctrl->bPreferedVersion;
        data[32] = ctrl->bMinVersion;
        data[33] = ctrl->bMaxVersion;
    }

    pipe = (SET_CUR & 0x80) ? usb_rcvctrlpipe(myuvc_udev, 0)
                  : usb_sndctrlpipe(myuvc_udev, 0);
    type |= (SET_CUR & 0x80) ? USB_DIR_IN : USB_DIR_OUT;

    ret = usb_control_msg(myuvc_udev, pipe, SET_CUR, type, VS_PROBE_CONTROL << 8,
            0 << 8 | myuvc_streaming_intf, data, size, 5000);

    kfree(data);
    
    return (ret < 0) ? ret : 0;
    
}


/* 參考: uvc_v4l2_try_format ∕uvc_probe_video 
 *       uvc_set_video_ctrl(video, probe, 1)
 */
static int myuvc_set_streaming_params(struct myuvc_streaming_control *ctrl)
{
    __u8 *data;
    __u16 size;
    int ret;
	__u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
	unsigned int pipe;
    
    size = uvc_version >= 0x0110 ? 34 : 26;
    data = kzalloc(size, GFP_KERNEL);
    if (data == NULL)
        return -ENOMEM;

    *(__le16 *)&data[0] = cpu_to_le16(ctrl->bmHint);
    data[2] = ctrl->bFormatIndex;
    data[3] = ctrl->bFrameIndex;
    *(__le32 *)&data[4] = cpu_to_le32(ctrl->dwFrameInterval);
    *(__le16 *)&data[8] = cpu_to_le16(ctrl->wKeyFrameRate);
    *(__le16 *)&data[10] = cpu_to_le16(ctrl->wPFrameRate);
    *(__le16 *)&data[12] = cpu_to_le16(ctrl->wCompQuality);
    *(__le16 *)&data[14] = cpu_to_le16(ctrl->wCompWindowSize);
    *(__le16 *)&data[16] = cpu_to_le16(ctrl->wDelay);
    put_unaligned_le32(ctrl->dwMaxVideoFrameSize, &data[18]);
    put_unaligned_le32(ctrl->dwMaxPayloadTransferSize, &data[22]);

    if (size == 34) {
        put_unaligned_le32(ctrl->dwClockFrequency, &data[26]);
        data[30] = ctrl->bmFramingInfo;
        data[31] = ctrl->bPreferedVersion;
        data[32] = ctrl->bMinVersion;
        data[33] = ctrl->bMaxVersion;
    }

    pipe = (SET_CUR & 0x80) ? usb_rcvctrlpipe(myuvc_udev, 0)
                  : usb_sndctrlpipe(myuvc_udev, 0);
    type |= (SET_CUR & 0x80) ? USB_DIR_IN : USB_DIR_OUT;

    ret = usb_control_msg(myuvc_udev, pipe, SET_CUR, type, VS_COMMIT_CONTROL << 8,
            0 << 8 | myuvc_streaming_intf, data, size, 5000);

    kfree(data);
    
    return (ret < 0) ? ret : 0;
    
}

static void myuvc_uninit_urbs(void)
{
    int i;
    for (i = 0; i < MYUVC_URBS; ++i) {
        if (myuvc_queue.urb_buffer[i])
        {
            usb_buffer_free(myuvc_udev, myuvc_queue.urb_size, myuvc_queue.urb_buffer[i], myuvc_queue.urb_dma[i]);
            myuvc_queue.urb_buffer[i] = NULL;
        }

        if (myuvc_queue.urb[i])
        {
            usb_free_urb(myuvc_queue.urb[i]);
            myuvc_queue.urb[i] = NULL;
        }
    }
}

/* 參考: uvc_video_complete / uvc_video_decode_isoc */
static void myuvc_video_complete(struct urb *urb)
{
	u8 *src;
    u8 *dest;
	int ret, i;
    int len;
    int maxlen;
    int nbytes;
    struct myuvc_buffer *buf;
    
	switch (urb->status) {
	case 0:
		break;

	default:
		printk("Non-zero status (%d) in video "
			"completion handler.\n", urb->status);
		return;
	}

    /* 從irqqueue佇列中取出第1個緩衝區 */
	if (!list_empty(&myuvc_queue.irqqueue))
	{
		buf = list_first_entry(&myuvc_queue.irqqueue, struct myuvc_buffer, irq);
    

    	for (i = 0; i < urb->number_of_packets; ++i) {
    		if (urb->iso_frame_desc[i].status < 0) {
    			printk("USB isochronous frame "
    				"lost (%d).\n", urb->iso_frame_desc[i].status);
    			continue;
    		}

            src  = urb->transfer_buffer + urb->iso_frame_desc[i].offset;

            dest = myuvc_queue.mem + buf->buf.m.offset + buf->buf.bytesused;

            len = urb->iso_frame_desc[i].actual_length;
            /* 判斷資料是否有效 */
            /* URB資料含義:
             * data[0] : 頭部長度
             * data[1] : 錯誤狀態
             */
            if (len < 2 || src[0] < 2 || src[0] > len)
                continue;
            
            /* Skip payloads marked with the error bit ("error frames"). */
            if (src[1] & UVC_STREAM_ERR) {
                printk("Dropping payload (error bit set).\n");
                continue;
            }

            /* 除去頭部後的資料長度 */
            len -= src[0];

            /* 緩衝區最多還能存多少資料 */
            maxlen = buf->buf.length - buf->buf.bytesused;
            nbytes = min(len, maxlen);

            /* 複製資料 */
            memcpy(dest, src + src[0], nbytes);
            buf->buf.bytesused += nbytes;

            /* 判斷一幀資料是否已經全部接收到 */
            if (len > maxlen) {
                buf->state = VIDEOBUF_DONE;
            }
            
            /* Mark the buffer as done if the EOF marker is set. */
            if (src[1] & UVC_STREAM_EOF && buf->buf.bytesused != 0) {
                printk("Frame complete (EOF found).\n");
                if (len == 0)
                    printk("EOF in empty payload.\n");
                buf->state = VIDEOBUF_DONE;
            }

    	}

        /* 當接收完一幀資料, 
         * 從irqqueue中刪除這個緩衝區
         * 喚醒等待資料的程序 
         */
        if (buf->state == VIDEOBUF_DONE ||
            buf->state == VIDEOBUF_ERROR)
        {
            list_del(&buf->irq);
            wake_up(&buf->wait);
        }
	}

    /* 再次提交URB */
	if ((ret = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
		printk("Failed to resubmit video URB (%d).\n", ret);
	}
}

/* 參考: uvc_init_video_isoc */
static int myuvc_alloc_init_urbs(void)
{
	u16 psize;
	u32 size;
    int npackets;
    int i;
    int j;

    struct urb *urb;

	psize = wMaxPacketSize; /* 實時傳輸端點一次能傳輸的最大位元組數 */
	size  = myuvc_params.dwMaxVideoFrameSize;  /* 一幀資料的最大長度 */
    npackets = DIV_ROUND_UP(size, psize);
    if (npackets > 32)
        npackets = 32;

    size = myuvc_queue.urb_size = psize * npackets;
    
    for (i = 0; i < MYUVC_URBS; ++i) {
        /* 1. 分配usb_buffers */
        
        myuvc_queue.urb_buffer[i] = usb_buffer_alloc(
            myuvc_udev, size,
            GFP_KERNEL | __GFP_NOWARN, &myuvc_queue.urb_dma[i]);

        /* 2. 分配urb */
		myuvc_queue.urb[i] = usb_alloc_urb(npackets, GFP_KERNEL);

        if (!myuvc_queue.urb_buffer[i] || !myuvc_queue.urb[i])
        {
            myuvc_uninit_urbs();
            return -ENOMEM;
        }

    }


    /* 3. 設定urb */
    for (i = 0; i < MYUVC_URBS; ++i) {
        urb = myuvc_queue.urb[i];
        
        urb->dev = myuvc_udev;
        urb->context = NULL;
        urb->pipe = usb_rcvisocpipe(myuvc_udev,myuvc_bEndpointAddress);
        urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
        urb->interval = 1;
        urb->transfer_buffer = myuvc_queue.urb_buffer[i];
        urb->transfer_dma = myuvc_queue.urb_dma[i];
        urb->complete = myuvc_video_complete;
        urb->number_of_packets = npackets;
        urb->transfer_buffer_length = size;
        
        for (j = 0; j < npackets; ++j) {
            urb->iso_frame_desc[j].offset = j * psize;
            urb->iso_frame_desc[j].length = psize;
        }
    
    }
    
    return 0;
}

/* A11 啟動傳輸 
 * 參考: uvc_video_enable(video, 1):
 *           uvc_commit_video
 *           uvc_init_video
 */
static int myuvc_vidioc_streamon(struct file *file, void *priv, enum v4l2_buf_type i)
{
    int ret;
    
    /* 1. 向USB攝像頭設定引數: 比如使用哪個format, 使用這個format下的哪個frame(解析度) 
     * 參考: uvc_set_video_ctrl / uvc_get_video_ctrl
     * 1.1 根據一個結構體uvc_streaming_control設定資料包: 可以手工設定,也可以讀出後再修改
     * 1.2 呼叫usb_control_msg發出資料包
     */

    /* a. 測試引數 */
    ret = myuvc_try_streaming_params(&myuvc_params);
    printk("myuvc_try_streaming_params ret = %d\n", ret);

    /* b. 取出引數 */
    ret = myuvc_get_streaming_params(&myuvc_params);
    printk("myuvc_get_streaming_params ret = %d\n", ret);

    /* c. 設定引數 */
    ret = myuvc_set_streaming_params(&myuvc_params);
    printk("myuvc_set_streaming_params ret = %d\n", ret);
    
    myuvc_print_streaming_params(&myuvc_params);

    /* d. 設定VideoStreaming Interface所使用的setting
     * d.1 從myuvc_params確定頻寬
     * d.2 根據setting的endpoint能傳輸的wMaxPacketSize
     *     找到能滿足該頻寬的setting
     */
    /* 手工確定:
     * bandwidth = myuvc_params.dwMaxPayloadTransferSize = 1024
     * 觀察lsusb -v -d 0x1e4e:的結果:
     *                wMaxPacketSize     0x0400  1x 1024 bytes
     * bAlternateSetting       8
     */
    usb_set_interface(myuvc_udev, myuvc_streaming_intf, myuvc_streaming_bAlternateSetting);
    
    /* 2. 分配設定URB */
    ret = myuvc_alloc_init_urbs();
    if (ret)
        printk("myuvc_alloc_init_urbs err : ret = %d\n", ret);

    /* 3. 提交URB以接收資料 */
	for (i = 0; i < MYUVC_URBS; ++i) {
		if ((ret = usb_submit_urb(myuvc_queue.urb[i], GFP_KERNEL)) < 0) {
			printk("Failed to submit URB %u (%d).\n", i, ret);
			myuvc_uninit_urbs();
			return ret;
		}
	}
    
	return 0;
}

/* A13 APP通過poll/select確定有資料後, 把快取從佇列中取出來
 * 參考: uvc_dequeue_buffer
 */
static int myuvc_vidioc_dqbuf(struct file *file, void *priv, struct v4l2_buffer *v4l2_buf)
{
    /* APP發現數據就緒後, 從mainqueue裡取出這個buffer */

    struct myuvc_buffer *buf;
    int ret = 0;

	if (list_empty(&myuvc_queue.mainqueue)) {
		ret = -EINVAL;
		goto done;
	}
    
	buf = list_first_entry(&myuvc_queue.mainqueue, struct myuvc_buffer, stream);

	switch (buf->state) {
	case VIDEOBUF_ERROR:
		ret = -EIO;
	case VIDEOBUF_DONE:
		buf->state = VIDEOBUF_IDLE;
		break;

	case VIDEOBUF_IDLE:
	case VIDEOBUF_QUEUED:
	case VIDEOBUF_ACTIVE:
	default:
		ret = -EINVAL;
		goto done;
	}

	list_del(&buf->stream);

done:
	return ret;
}

/*
 * A14 之前已經通過mmap映射了快取, APP可以直接讀資料
 * A15 再次呼叫myuvc_vidioc_qbuf把快取放入佇列
 * A16 poll...
 */

/* A17 停止 
 * 參考 : uvc_video_enable(video, 0)
 */
static int myuvc_vidioc_streamoff(struct file *file, void *priv, enum v4l2_buf_type t)
{
	struct urb *urb;
	unsigned int i;

    /* 1. kill URB */
	for (i = 0; i < MYUVC_URBS; ++i) {
		if ((urb = myuvc_queue.urb[i]) == NULL)
			continue;
		usb_kill_urb(urb);
	}

    /* 2. free URB */
    myuvc_uninit_urbs();

    /* 3. 設定VideoStreaming Interface為setting 0 */
    usb_set_interface(myuvc_udev, myuvc_streaming_intf, 0);
    
    return 0;
}

    /* Control handling */


/* Extract the bit string specified by mapping->offset and mapping->size
 * from the little-endian data stored at 'data' and return the result as
 * a signed 32bit integer. Sign extension will be performed if the mapping
 * references a signed data type.
 */
static __s32 myuvc_get_le_value(const __u8 *data)
{
    int bits = 16;
    int offset = 0;
    __s32 value = 0;
    __u8 mask;

    data += offset / 8;
    offset &= 7;
    mask = ((1LL << bits) - 1) << offset;

    for (; bits > 0; data++) {
        __u8 byte = *data & mask;
        value |= offset > 0 ? (byte >> offset) : (byte << (-offset));
        bits -= 8 - (offset > 0 ? offset : 0);
        offset -= 8;
        mask = (1 << bits) - 1;
    }

    /* Sign-extend the value if needed. */
    value |= -(value & (1 << (16 - 1)));

    return value;
}

/* Set the bit string specified by mapping->offset and mapping->size
 * in the little-endian data stored at 'data' to the value 'value'.
 */
static void myuvc_set_le_value(__s32 value, __u8 *data)
{
	int bits = 16;
	int offset = 0;
	__u8 mask;

	data += offset / 8;
	offset &= 7;

	for (; bits > 0; data++) {
		mask = ((1LL << bits) - 1) << offset;
		*data = (*data & ~mask) | ((value << offset) & mask);
		value >>= offset ? offset : 8;
		bits -= 8 - offset;
		offset = 0;
	}
}
    


/* 參考:uvc_query_v4l2_ctrl */    
int myuvc_vidioc_queryctrl (struct file *file, void *fh,
                struct v4l2_queryctrl *ctrl)
{
	__u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
	unsigned int pipe;
    int ret;
    u8 data[2];

    if (ctrl->id != V4L2_CID_BRIGHTNESS)
        return -EINVAL;
    
	memset(ctrl, 0, sizeof *ctrl);
	ctrl->id   = V4L2_CID_BRIGHTNESS;
	ctrl->type = V4L2_CTRL_TYPE_INTEGER;
	strcpy(ctrl->name, "MyUVC_BRIGHTNESS");
	ctrl->flags = 0;

	pipe = usb_rcvctrlpipe(myuvc_udev, 0);
	type |= USB_DIR_IN;

    /* 發起USB傳輸確定這些值 */
	ret = usb_control_msg(myuvc_udev, pipe, GET_MIN, type, PU_BRIGHTNESS_CONTROL << 8,
			ProcessingUnitID << 8 | myuvc_control_intf, data, 2, 5000);
    if (ret != 2)
        return -EIO;
	ctrl->minimum = myuvc_get_le_value(data);	/* Note signedness */


	ret = usb_control_msg(myuvc_udev, pipe, GET_MAX, type,  PU_BRIGHTNESS_CONTROL << 8,
			ProcessingUnitID << 8 | myuvc_control_intf, data, 2, 5000);
    if (ret != 2)
        return -EIO;
	ctrl->maximum = myuvc_get_le_value(data);	/* Note signedness */

	ret = usb_control_msg(myuvc_udev, pipe, GET_RES, type, PU_BRIGHTNESS_CONTROL << 8,
			 ProcessingUnitID << 8 | myuvc_control_intf, data, 2, 5000);
    if (ret != 2)
        return -EIO;
	ctrl->step = myuvc_get_le_value(data);	/* Note signedness */

	ret = usb_control_msg(myuvc_udev, pipe, GET_DEF, type, PU_BRIGHTNESS_CONTROL << 8,
			ProcessingUnitID << 8 | myuvc_control_intf, data, 2, 5000);
    if (ret != 2)
        return -EIO;
	ctrl->default_value = myuvc_get_le_value(data);	/* Note signedness */

    printk("Brightness: min =%d, max = %d, step = %d, default = %d\n", ctrl->minimum, ctrl->maximum, ctrl->step, ctrl->default_value);
    
    return 0;
}

/* 參考 : uvc_ctrl_get */
int myuvc_vidioc_g_ctrl (struct file *file, void *fh,
                struct v4l2_control *ctrl)
{
	__u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
	unsigned int pipe;
    int ret;
    u8 data[2];
    
    if (ctrl->id != V4L2_CID_BRIGHTNESS)
        return -EINVAL;

	pipe = usb_rcvctrlpipe(myuvc_udev, 0);
	type |= USB_DIR_IN;

	ret = usb_control_msg(myuvc_udev, pipe, GET_CUR, type, PU_BRIGHTNESS_CONTROL << 8,
			ProcessingUnitID << 8 | myuvc_control_intf, data, 2, 5000);
    if (ret != 2)
        return -EIO;
	ctrl->value = myuvc_get_le_value(data);	/* Note signedness */
    
    return 0;
}

/* 參考: uvc_ctrl_set/uvc_ctrl_commit */
int myuvc_vidioc_s_ctrl (struct file *file, void *fh,
                struct v4l2_control *ctrl)
{
    __u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
    unsigned int pipe;
    int ret;
    u8 data[2];
    
    if (ctrl->id != V4L2_CID_BRIGHTNESS)
        return -EINVAL;

    myuvc_set_le_value(ctrl->value, data);

    pipe = usb_sndctrlpipe(myuvc_udev, 0);
    type |= USB_DIR_OUT;

    ret = usb_control_msg(myuvc_udev, pipe, SET_CUR, type, PU_BRIGHTNESS_CONTROL << 8,
            ProcessingUnitID  << 8 | myuvc_control_intf, data, 2, 5000);
    if (ret != 2)
        return -EIO;
    
    return 0;
}



static const struct v4l2_ioctl_ops myuvc_ioctl_ops = {
        // 表示它是一個攝像頭裝置
        .vidioc_querycap      = myuvc_vidioc_querycap,

        /* 用於列舉、獲得、測試、設定攝像頭的資料的格式 */
        .vidioc_enum_fmt_vid_cap  = myuvc_vidioc_enum_fmt_vid_cap,
        .vidioc_g_fmt_vid_cap     = myuvc_vidioc_g_fmt_vid_cap,
        .vidioc_try_fmt_vid_cap   = myuvc_vidioc_try_fmt_vid_cap,
        .vidioc_s_fmt_vid_cap     = myuvc_vidioc_s_fmt_vid_cap,
        
        /* 緩衝區操作: 申請/查詢/放入佇列/取出佇列 */
        .vidioc_reqbufs       = myuvc_vidioc_reqbufs,
        .vidioc_querybuf      = myuvc_vidioc_querybuf,
        .vidioc_qbuf          = myuvc_vidioc_qbuf,
        .vidioc_dqbuf         = myuvc_vidioc_dqbuf,

        /* 查詢/獲得/設定屬性 */
        .vidioc_queryctrl     = myuvc_vidioc_queryctrl,
        .vidioc_g_ctrl        = myuvc_vidioc_g_ctrl,
        .vidioc_s_ctrl        = myuvc_vidioc_s_ctrl,
        
        // 啟動/停止
        .vidioc_streamon      = myuvc_vidioc_streamon,
        .vidioc_streamoff     = myuvc_vidioc_streamoff,   
};

/* A1 */
static int myuvc_open(struct file *file)
{
	return 0;
}

static void myuvc_vm_open(struct vm_area_struct *vma)
{
	struct myuvc_buffer *buffer = vma->vm_private_data;
	buffer->vma_use_count++;
}

static void myuvc_vm_close(struct vm_area_struct *vma)
{
	struct myuvc_buffer *buffer = vma->vm_private_data;
	buffer->vma_use_count--;
}

static struct vm_operations_struct myuvc_vm_ops = {
	.open		= myuvc_vm_open,
	.close		= myuvc_vm_close,
};


/* A9 把快取對映到APP的空間,以後APP就可以直接操作這塊快取 
 * 參考: uvc_v4l2_mmap
 */
static int myuvc_mmap(struct file *file, struct vm_area_struct *vma)
{
    struct myuvc_buffer *buffer;
    struct page *page;
    unsigned long addr, start, size;
    unsigned int i;
    int ret = 0;

    start = vma->vm_start;
    size = vma->vm_end - vma->vm_start;

    /* 應用程式呼叫mmap函式時, 會傳入offset引數
     * 根據這個offset找出指定的緩衝區
     */
    for (i = 0; i < myuvc_queue.count; ++i) {
        buffer = &myuvc_queue.buffer[i];
        if ((buffer->buf.m.offset >> PAGE_SHIFT) == vma->vm_pgoff)
            break;
    }

    if (i == myuvc_queue.count || size != myuvc_queue.buf_size) {
        ret = -EINVAL;
        goto done;
    }

    /*
     * VM_IO marks the area as being an mmaped region for I/O to a
     * device. It also prevents the region from being core dumped.
     */
    vma->vm_flags |= VM_IO;

    /* 根據虛擬地址找到緩衝區對應的page構體 */
    addr = (unsigned long)myuvc_queue.mem + buffer->buf.m.offset;
    while (size > 0) {
        page = vmalloc_to_page((void *)addr);

        /* 把page和APP傳入的虛擬地址掛構 */
        if ((ret = vm_insert_page(vma, start, page)) < 0)
            goto done;

        start += PAGE_SIZE;
        addr += PAGE_SIZE;
        size -= PAGE_SIZE;
    }

    vma->vm_ops = &myuvc_vm_ops;
    vma->vm_private_data = buffer;
    myuvc_vm_open(vma);

done:
    return ret;
}

/* A12 APP呼叫POLL/select來確定快取是否就緒(有資料) 
 * 參考 : uvc_v4l2_poll
 */
static unsigned int myuvc_poll(struct file *file, struct poll_table_struct *wait)
{
	struct myuvc_buffer *buf;
	unsigned int mask = 0;
    
    /* 從mainqueuq中取出第1個緩衝區 */

    /*判斷它的狀態, 如果未就緒, 休眠 */

    if (list_empty(&myuvc_queue.mainqueue)) {
        mask |= POLLERR;
        goto done;
    }
    
    buf = list_first_entry(&myuvc_queue.mainqueue, struct myuvc_buffer, stream);

    poll_wait(file, &buf->wait, wait);
    if (buf->state == VIDEOBUF_DONE ||
        buf->state == VIDEOBUF_ERROR)
        mask |= POLLIN | POLLRDNORM;
    
done:
    return mask;
}

/* A18 關閉 */
static int myuvc_close(struct file *file)
{
    
	return 0;
}

static const struct v4l2_file_operations myuvc_fops = {
	.owner		= THIS_MODULE,
    .open       = myuvc_open,
    .release    = myuvc_close,
    .mmap       = myuvc_mmap,
    .ioctl      = video_ioctl2, /* V4L2 ioctl handler */
    .poll       = myuvc_poll,
};

static void myuvc_release(struct video_device *vdev)
{
}


static int myuvc_probe(struct usb_interface *intf,
		     const struct usb_device_id *id)
{
    static int cnt = 0;
	struct usb_device *dev = interface_to_usbdev(intf);

    myuvc_udev = dev;

    printk("myuvc_probe : cnt = %d\n", cnt++);

    if (cnt == 1)
    {
        myuvc_control_intf = intf->cur_altsetting->desc.bInterfaceNumber;
    }
    else if (cnt == 2)
    {
        myuvc_streaming_intf = intf->cur_altsetting->desc.bInterfaceNumber;
    }

    if (cnt == 2)
    {
        /* 1. 分配一個video_device結構體 */
        myuvc_vdev = video_device_alloc();

        /* 2. 設定 */
        /* 2.1 */
        myuvc_vdev->release = myuvc_release;
        
        /* 2.2 */
        myuvc_vdev->fops    = &myuvc_fops;
        
        /* 2.3 */
        myuvc_vdev->ioctl_ops = &myuvc_ioctl_ops;

        /* 3. 註冊 */
        video_register_device(myuvc_vdev, VFL_TYPE_GRABBER, -1);
    }
    
    
    return 0;
}

static void myuvc_disconnect(struct usb_interface *intf)
{
    static int cnt = 0;
    printk("myuvc_disconnect : cnt = %d\n", cnt++);

    if (cnt == 2)
    {
        video_unregister_device(myuvc_vdev);
        video_device_release(myuvc_vdev);
    }
    
}

static struct usb_device_id myuvc_ids[] = {
	/* Generic USB Video Class */
	{ USB_INTERFACE_INFO(USB_CLASS_VIDEO, 1, 0) },  /* VideoControl Interface */
    { USB_INTERFACE_INFO(USB_CLASS_VIDEO, 2, 0) },  /* VideoStreaming Interface */
	{}
};

/* 1. 分配usb_driver */
/* 2. 設定 */
static struct usb_driver myuvc_driver = {
    .name       = "myuvc",
    .probe      = myuvc_probe,
    .disconnect = myuvc_disconnect,
    .id_table   = myuvc_ids,
};

static int myuvc_init(void)
{
    /* 3. 註冊 */
    usb_register(&myuvc_driver);
    return 0;
}

static void myuvc_exit(void)
{
    usb_deregister(&myuvc_driver);
}

module_init(myuvc_init);
module_exit(myuvc_exit);

MODULE_LICENSE("GPL");

uvcvideo.h
#ifndef _USB_VIDEO_H_
#define _USB_VIDEO_H_

#include <linux/kernel.h>
#include <linux/videodev2.h>

/*
 * Dynamic controls
 */

/* Data types for UVC control data */
#define UVC_CTRL_DATA_TYPE_RAW		0
#define UVC_CTRL_DATA_TYPE_SIGNED	1
#define UVC_CTRL_DATA_TYPE_UNSIGNED	2
#define UVC_CTRL_DATA_TYPE_BOOLEAN	3
#define UVC_CTRL_DATA_TYPE_ENUM		4
#define UVC_CTRL_DATA_TYPE_BITMASK	5

/* Control flags */
#define UVC_CONTROL_SET_CUR	(1 << 0)
#define UVC_CONTROL_GET_CUR	(1 << 1)
#define UVC_CONTROL_GET_MIN	(1 << 2)
#define UVC_CONTROL_GET_MAX	(1 << 3)
#define UVC_CONTROL_GET_RES	(1 << 4)
#define UVC_CONTROL_GET_DEF	(1 << 5)
/* Control should be saved at suspend and restored at resume. */
#define UVC_CONTROL_RESTORE	(1 << 6)
/* Control can be updated by the camera. */
#define UVC_CONTROL_AUTO_UPDATE	(1 << 7)

#define UVC_CONTROL_GET_RANGE	(UVC_CONTROL_GET_CUR | UVC_CONTROL_GET_MIN | \
				 UVC_CONTROL_GET_MAX | UVC_CONTROL_GET_RES | \
				 UVC_CONTROL_GET_DEF)

struct uvc_xu_control_info {
	__u8 entity[16];
	__u8 index;
	__u8 selector;
	__u16 size;
	__u32 flags;
};

struct uvc_xu_control_mapping {
	__u32 id;
	__u8 name[32];
	__u8 entity[16];
	__u8 selector;

	__u8 size;
	__u8 offset;
	enum v4l2_ctrl_type v4l2_type;
	__u32 data_type;
};

struct uvc_xu_control {
	__u8 unit;
	__u8 selector;
	__u16 size;
	__u8 __user *data;
};

#define UVCIOC_CTRL_ADD		_IOW('U', 1, struct uvc_xu_control_info)
#define UVCIOC_CTRL_MAP		_IOWR('U', 2, struct uvc_xu_control_mapping)
#define UVCIOC_CTRL_GET		_IOWR('U', 3, struct uvc_xu_control)
#define UVCIOC_CTRL_SET		_IOW('U', 4, struct uvc_xu_control)

#ifdef __KERNEL__

#include <linux/poll.h>

/* --------------------------------------------------------------------------
 * UVC constants
 */

#define SC_UNDEFINED			0x00
#define SC_VIDEOCONTROL			0x01
#define SC_VIDEOSTREAMING		0x02
#define SC_VIDEO_INTERFACE_COLLECTION	0x03

#define PC_PROTOCOL_UNDEFINED		0x00

#define CS_UNDEFINED			0x20
#define CS_DEVICE			0x21
#define CS_CONFIGURATION		0x22
#define CS_STRING			0x23
#define CS_INTERFACE			0x24
#define CS_ENDPOINT			0x25

/* VideoControl class specific interface descriptor */
#define VC_DESCRIPTOR_UNDEFINED		0x00
#define VC_HEADER			0x01
#define VC_INPUT_TERMINAL		0x02
#define VC_OUTPUT_TERMINAL		0x03
#define VC_SELECTOR_UNIT		0x04
#define VC_PROCESSING_UNIT		0x05
#define VC_EXTENSION_UNIT		0x06

/* VideoStreaming class specific interface descriptor */
#define VS_UNDEFINED			0x00
#define VS_INPUT_HEADER			0x01
#define VS_OUTPUT_HEADER		0x02
#define VS_STILL_IMAGE_FRAME		0x03
#define VS_FORMAT_UNCOMPRESSED		0x04
#define VS_FRAME_UNCOMPRESSED		0x05
#define VS_FORMAT_MJPEG			0x06
#define VS_FRAME_MJPEG			0x07
#define VS_FORMAT_MPEG2TS		0x0a
#define VS_FORMAT_DV			0x0c
#define VS_COLORFORMAT			0x0d
#define VS_FORMAT_FRAME_BASED		0x10
#define VS_FRAME_FRAME_BASED		0x11
#define VS_FORMAT_STREAM_BASED		0x12

/* Endpoint type */
#define EP_UNDEFINED			0x00
#define EP_GENERAL			0x01
#define EP_ENDPOINT			0x02
#define EP_INTERRUPT			0x03

/* Request codes */
#define RC_UNDEFINED			0x00
#define SET_CUR				0x01
#define GET_CUR				0x81
#define GET_MIN				0x82
#define GET_MAX				0x83
#define GET_RES				0x84
#define GET_LEN				0x85
#define GET_INFO			0x86
#define GET_DEF				0x87

/* VideoControl interface controls */
#define VC_CONTROL_UNDEFINED		0x00
#define VC_VIDEO_POWER_MODE_CONTROL	0x01
#define VC_REQUEST_ERROR_CODE_CONTROL	0x02

/* Terminal controls */
#define TE_CONTROL_UNDEFINED		0x00

/* Selector Unit controls */
#define SU_CONTROL_UNDEFINED		0x00
#define SU_INPUT_SELECT_CONTROL		0x01

/* Camera Terminal controls */
#define CT_CONTROL_UNDEFINED				0x00
#define CT_SCANNING_MODE_CONTROL			0x01
#define CT_AE_MODE_CONTROL				0x02
#define CT_AE_PRIORITY_CONTROL				0x03
#define CT_EXPOSURE_TIME_ABSOLUTE_CONTROL		0x04
#define CT_EXPOSURE_TIME_RELATIVE_CONTROL		0x05
#define CT_FOCUS_ABSOLUTE_CONTROL			0x06
#define CT_FOCUS_RELATIVE_CONTROL			0x07
#define CT_FOCUS_AUTO_CONTROL				0x08
#define CT_IRIS_ABSOLUTE_CONTROL			0x09
#define CT_IRIS_RELATIVE_CONTROL			0x0a
#define CT_ZOOM_ABSOLUTE_CONTROL			0x0b
#define CT_ZOOM_RELATIVE_CONTROL			0x0c
#define CT_PANTILT_ABSOLUTE_CONTROL			0x0d
#define CT_PANTILT_RELATIVE_CONTROL			0x0e
#define CT_ROLL_ABSOLUTE_CONTROL			0x0f
#define CT_ROLL_RELATIVE_CONTROL			0x10
#define CT_PRIVACY_CONTROL				0x11

/* Processing Unit controls */
#define PU_CONTROL_UNDEFINED				0x00
#define PU_BACKLIGHT_COMPENSATION_CONTROL		0x01
#define PU_BRIGHTNESS_CONTROL				0x02
#define PU_CONTRAST_CONTROL				0x03
#define PU_GAIN_CONTROL					0x04
#define PU_POWER_LINE_FREQUENCY_CONTROL			0x05
#define PU_HUE_CONTROL					0x06
#define PU_SATURATION_CONTROL				0x07
#define PU_SHARPNESS_CONTROL				0x08
#define PU_GAMMA_CONTROL				0x09
#define PU_WHITE_BALANCE_TEMPERATURE_CONTROL		0x0a
#define PU_WHITE_BALANCE_TEMPERATURE_AUTO_CONTROL	0x0b
#define PU_WHITE_BALANCE_COMPONENT_CONTROL		0x0c
#define PU_WHITE_BALANCE_COMPONENT_AUTO_CONTROL		0x0d
#define PU_DIGITAL_MULTIPLIER_CONTROL			0x0e
#define PU_DIGITAL_MULTIPLIER_LIMIT_CONTROL		0x0f
#define PU_HUE_AUTO_CONTROL				0x10
#define PU_ANALOG_VIDEO_STANDARD_CONTROL		0x11
#define PU_ANALOG_LOCK_STATUS_CONTROL			0x12

#define LXU_MOTOR_PANTILT_RELATIVE_CONTROL		0x01
#define LXU_MOTOR_PANTILT_RESET_CONTROL			0x02
#define LXU_MOTOR_FOCUS_MOTOR_CONTROL			0x03

/* VideoStreaming interface controls */
#define VS_CONTROL_UNDEFINED		0x00
#define VS_PROBE_CONTROL		0x01
#define VS_COMMIT_CONTROL		0x02
#define VS_STILL_PROBE_CONTROL		0x03
#define VS_STILL_COMMIT_CONTROL		0x04
#define VS_STILL_IMAGE_TRIGGER_CONTROL	0x05
#define VS_STREAM_ERROR_CODE_CONTROL	0x06
#define VS_GENERATE_KEY_FRAME_CONTROL	0x07
#define VS_UPDATE_FRAME_SEGMENT_CONTROL	0x08
#define VS_SYNC_DELAY_CONTROL		0x09

#define TT_VENDOR_SPECIFIC		0x0100
#define TT_STREAMING			0x0101

/* Input Terminal types */
#define ITT_VENDOR_SPECIFIC		0x0200
#define ITT_CAMERA			0x0201
#define ITT_MEDIA_TRANSPORT_INPUT	0x0202

/* Output Terminal types */
#define OTT_VENDOR_SPECIFIC		0x0300
#define OTT_DISPLAY			0x0301
#define OTT_MEDIA_TRANSPORT_OUTPUT	0x0302

/* External Terminal types */
#define EXTERNAL_VENDOR_SPECIFIC	0x0400
#define COMPOSITE_CONNECTOR		0x0401
#define SVIDEO_CONNECTOR		0x0402
#define COMPONENT_CONNECTOR		0x0403

#define UVC_TERM_INPUT			0x0000
#define UVC_TERM_OUTPUT			0x8000

#define UVC_ENTITY_TYPE(entity)		((entity)->type & 0x7fff)
#define UVC_ENTITY_IS_UNIT(entity)	(((entity)->type & 0xff00) == 0)
#define UVC_ENTITY_IS_TERM(entity)	(((entity)->type & 0xff00) != 0)
#define UVC_ENTITY_IS_ITERM(entity) \
	(((entity)->type & 0x8000) == UVC_TERM_INPUT)
#define UVC_ENTITY_IS_OTERM(entity) \
	(((entity)->type & 0x8000) == UVC_TERM_OUTPUT)

#define UVC_STATUS_TYPE_CONTROL		1
#define UVC_STATUS_TYPE_STREAMING	2

/* ------------------------------------------------------------------------
 * GUIDs
 */
#define UVC_GUID_UVC_CAMERA \
	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
	 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01}
#define UVC_GUID_UVC_OUTPUT \
	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
	 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02}
#define UVC_GUID_UVC_MEDIA_TRANSPORT_INPUT \
	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
	 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03}
#define UVC_GUID_UVC_PROCESSING \
	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
	 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01}
#define UVC_GUID_UVC_SELECTOR \
	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
	 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02}

#define UVC_GUID_LOGITECH_DEV_INFO \
	{0x82, 0x06, 0x61, 0x63, 0x70, 0x50, 0xab, 0x49, \
	 0xb8, 0xcc, 0xb3, 0x85, 0x5e, 0x8d, 0x22, 0x1e}
#define UVC_GUID_LOGITECH_USER_HW \
	{0x82, 0x06, 0x61, 0x63, 0x70, 0x50, 0xab, 0x49, \
	 0xb8, 0xcc, 0xb3, 0x85, 0x5e, 0x8d, 0x22, 0x1f}
#define UVC_GUID_LOGITECH_VIDEO \
	{0x82, 0x06, 0x61, 0x63, 0x70, 0x50, 0xab, 0x49, \
	 0xb8, 0xcc, 0xb3, 0x85, 0x5e, 0x8d, 0x22, 0x50}
#define UVC_GUID_LOGITECH_MOTOR \
	{0x82, 0x06, 0x61, 0x63, 0x70, 0x50, 0xab, 0x49, \
	 0xb8, 0xcc, 0xb3, 0x85, 0x5e, 0x8d, 0x22, 0x56}

#define UVC_GUID_FORMAT_MJPEG \
	{ 'M',  'J',  'P',  'G', 0x00, 0x00, 0x10, 0x00, \
	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
#define UVC_GUID_FORMAT_YUY2 \
	{ 'Y',  'U',  'Y',  '2', 0x00, 0x00, 0x10, 0x00, \
	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
#define UVC_GUID_FORMAT_NV12 \
	{ 'N',  'V',  '1',  '2', 0x00, 0x00, 0x10, 0x00, \
	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
#define UVC_GUID_FORMAT_YV12 \
	{ 'Y',  'V',  '1',  '2', 0x00, 0x00, 0x10, 0x00, \
	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
#define UVC_GUID_FORMAT_I420 \
	{ 'I',  '4',  '2',  '0', 0x00, 0x00, 0x10, 0x00, \
	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
#define UVC_GUID_FORMAT_UYVY \
	{ 'U',  'Y',  'V',  'Y', 0x00, 0x00, 0x10, 0x00, \
	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
#define UVC_GUID_FORMAT_Y800 \
	{ 'Y',  '8',  '0',  '0', 0x00, 0x00, 0x10, 0x00, \
	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
#define UVC_GUID_FORMAT_BY8 \
	{ 'B',  'Y',  '8',  ' ', 0x00, 0x00, 0x10, 0x00, \
	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}


/* ------------------------------------------------------------------------
 * Driver specific constants.
 */

#define DRIVER_VERSION_NUMBER	KERNEL_VERSION(0, 1, 0)

/* Number of isochronous URBs. */
#define UVC_URBS		5
/* Maximum number of packets per URB. */
#define UVC_MAX_PACKETS		32
/* Maximum number of video buffers. */
#define UVC_MAX_VIDEO_BUFFERS	32
/* Maximum status buffer size in bytes of interrupt URB. */
#define UVC_MAX_STATUS_SIZE	16

#define UVC_CTRL_CONTROL_TIMEOUT	300
#define UVC_CTRL_STREAMING_TIMEOUT	3000

/* Devices quirks */
#define UVC_QUIRK_STATUS_INTERVAL	0x00000001
#define UVC_QUIRK_PROBE_MINMAX		0x00000002
#define UVC_QUIRK_PROBE_EXTRAFIELDS	0x00000004
#define UVC_QUIRK_BUILTIN_ISIGHT	0x00000008
#define UVC_QUIRK_STREAM_NO_FID		0x00000010
#define UVC_QUIRK_IGNORE_SELECTOR_UNIT	0x00000020
#define UVC_QUIRK_FIX_BANDWIDTH		0x00000080

/* Format flags */
#define UVC_FMT_FLAG_COMPRESSED		0x00000001
#define UVC_FMT_FLAG_STREAM		0x00000002

/* ------------------------------------------------------------------------
 * Structures.
 */

struct uvc_device;

/* TODO: Put the most frequently accessed fields at the beginning of
 * structures to maximize cache efficiency.
 */
struct uvc_streaming_control {
	__u16 bmHint;
	__u8  bFormatIndex;
	__u8  bFrameIndex;
	__u32 dwFrameInterval;
	__u16 wKeyFrameRate;
	__u16 wPFrameRate;
	__u16 wCompQuality;
	__u16 wCompWindowSize;
	__u16 wDelay;
	__u32 dwMaxVideoFrameSize;
	__u32 dwMaxPayloadTransferSize;
	__u32 dwClockFrequency;
	__u8  bmFramingInfo;
	__u8  bPreferedVersion;
	__u8  bMinVersion;
	__u8  bMaxVersion;
};

struct uvc_menu_info {
	__u32 value;
	__u8 name[32];
};

struct uvc_control_info {
	struct list_head list;
	struct list_head mappings;

	__u8 entity[16];
	__u8 index;
	__u8 selector;

	__u16 size;
	__u32 flags;
};

struct uvc_control_mapping {
	struct list_head list;

	struct uvc_control_info *ctrl;

	__u32 id;
	__u8 name[32];
	__u8 entity[16];
	__u8 selector;

	__u8 size;
	__u8 offset;
	enum v4l2_ctrl_type v4l2_type;
	__u32 data_type;

	struct uvc_menu_info *menu_info;
	__u32 menu_count;

	__s32 (*get) (struct uvc_control_mapping *mapping, __u8 query,
		      const __u8 *data);
	void (*set) (struct uvc_control_mapping *mapping, __s32 value,
		     __u8 *data);
};

struct uvc_control {
	struct uvc_entity *entity;
	struct uvc_control_info *info;

	__u8 index;	/* Used to match the uvc_control entry with a
			   uvc_control_info. */
	__u8 dirty : 1,
	     loaded : 1,
	     modified : 1;

	__u8 *data;
};

struct uvc_format_desc {
	char *name;
	__u8 guid[16];
	__u32 fcc;
};

/* The term 'entity' refers to both UVC units and UVC terminals.
 *
 * The type field is either the terminal type (wTerminalType in the terminal
 * descriptor), or the unit type (bDescriptorSubtype in the unit descriptor).
 * As the bDescriptorSubtype field is one byte long, the type value will
 * always have a null MSB for units. All terminal types defined by the UVC
 * specification have a non-null MSB, so it is safe to use the MSB to
 * differentiate between units and terminals as long as the descriptor parsing
 * code makes sure terminal types have a non-null MSB.
 *
 * For terminals, the type's most significant bit stores the terminal
 * direction (either UVC_TERM_INPUT or UVC_TERM_OUTPUT). The type field should
 * always be accessed with the UVC_ENTITY_* macros and never directly.
 */

struct uvc_entity {
	struct list_head list;		/* Entity as part of a UVC device. */
	struct list_head chain;		/* Entity as part of a video device
					 * chain. */
	__u8 id;
	__u16 type;
	char name[64];

	union {
		struct {
			__u16 wObjectiveFocalLengthMin;
			__u16 wObjectiveFocalLengthMax;
			__u16 wOcularFocalLength;
			__u8  bControlSize;
			__u8  *bmControls;
		} camera;

		struct {
			__u8  bControlSize;
			__u8  *bmControls;
			__u8  bTransportModeSize;
			__u8  *bmTransportModes;
		} media;

		struct {
			__u8  bSourceID;
		} output;

		struct {
			__u8  bSourceID;
			__u16 wMaxMultiplier;
			__u8  bControlSize;
			__u8  *bmControls;
			__u8  bmVideoStandards;
		} processing;

		struct {
			__u8  bNrInPins;
			__u8  *baSourceID;
		} selector;

		struct {
			__u8  guidExtensionCode[16];
			__u8  bNumControls;
			__u8  bNrInPins;
			__u8  *baSourceID;
			__u8  bControlSize;
			__u8  *bmControls;
			__u8  *bmControlsType;
		} extension;
	};

	unsigned int ncontrols;
	struct uvc_control *controls;
};

struct uvc_frame {
	__u8  bFrameIndex;
	__u8  bmCapabilities;
	__u16 wWidth;
	__u16 wHeight;
	__u32 dwMinBitRate;
	__u32 dwMaxBitRate;
	__u32 dwMaxVideoFrameBufferSize;
	__u8  bFrameIntervalType;
	__u32 dwDefaultFrameInterval;
	__u32 *dwFrameInterval;
};

struct uvc_format {
	__u8 type;
	__u8 index;
	__u8 bpp;
	__u8 colorspace;
	__u32 fcc;
	__u32 flags;

	char name[32];

	unsigned int nframes;
	struct uvc_frame *frame;
};

struct uvc_streaming_header {
	__u8 bNumFormats;
	__u8 bEndpointAddress;
	__u8 bTerminalLink;
	__u8 bControlSize;
	__u8 *bmaControls;
	/* The following fields are used by input headers only. */
	__u8 bmInfo;
	__u8 bStillCaptureMethod;
	__u8 bTriggerSupport;
	__u8 bTriggerUsage;
};

struct uvc_streaming {
	struct list_head list;

	struct usb_interface *intf;
	int intfnum;
	__u16 maxpsize;

	struct uvc_streaming_header header;
	enum v4l2_buf_type type;

	unsigned int nformats;
	struct uvc_format *format;

	struct uvc_streaming_control ctrl;
	struct uvc_format *cur_format;
	struct uvc_frame *cur_frame;

	struct mutex mutex;
};

enum uvc_buffer_state {
	UVC_BUF_STATE_IDLE	= 0,
	UVC_BUF_STATE_QUEUED	= 1,
	UVC_BUF_STATE_ACTIVE	= 2,
	UVC_BUF_STATE_DONE	= 3,
	UVC_BUF_STATE_ERROR	= 4,
};

struct uvc_buffer {
	unsigned long vma_use_count;
	struct list_head stream;

	/* Touched by interrupt handler. */
	struct v4l2_buffer buf;
	struct list_head queue;
	wait_queue_head_t wait;
	enum uvc_buffer_state state;
};

#define UVC_QUEUE_STREAMING		(1 << 0)
#define UVC_QUEUE_DISCONNECTED		(1 << 1)
#define UVC_QUEUE_DROP_INCOMPLETE	(1 << 2)

struct uvc_video_queue {
	enum v4l2_buf_type type;

	void *mem;
	unsigned int flags;
	__u32 sequence;

	unsigned int count;
	unsigned int buf_size;
	unsigned int buf_used;
	struct uvc_buffer buffer[UVC_MAX_VIDEO_BUFFERS];
	struct mutex mutex;	/* protects buffers and mainqueue */
	spinlock_t irqlock;	/* protects irqqueue */

	struct list_head mainqueue;
	struct list_head irqqueue;
};

struct uvc_video_device {
	struct uvc_device *dev;
	struct video_device *vdev;
	atomic_t active;
	unsigned int frozen : 1;

	struct list_head iterms;		/* Input terminals */
	struct uvc_entity *oterm;		/* Output terminal */
	struct uvc_entity *sterm;		/* USB streaming terminal */
	struct uvc_entity *processing;
	struct uvc_entity *selector;
	struct list_head extensions;
	struct mutex ctrl_mutex;

	struct uvc_video_queue queue;

	/* Video streaming object, must always be non-NULL. */
	struct uvc_streaming *streaming;

	void (*decode) (struct urb *urb, struct uvc_video_device *video,
			struct uvc_buffer *buf);

	/* Context data used by the bulk completion handler. */
	struct {
		__u8 header[256];
		unsigned int header_size;
		int skip_payload;
		__u32 payload_size;
		__u32 max_payload_size;
	} bulk;

	struct urb *urb[UVC_URBS];
	char *urb_buffer[UVC_URBS];
	dma_addr_t urb_dma[UVC_URBS];
	unsigned int urb_size;

	__u8 last_fid;
};

enum uvc_device_state {
	UVC_DEV_DISCONNECTED = 1,
};

struct uvc_device {
	struct usb_device *udev;
	struct usb_interface *intf;
	unsigned long warnings;
	__u32 quirks;
	int intfnum;
	char name[32];

	enum uvc_device_state state;
	struct kref kref;
	struct list_head list;
	atomic_t users;

	/* Video control interface */
	__u16 uvc_version;
	__u32 clock_frequency;

	struct list_head entities;

	struct uvc_video_device video;

	/* Status Interrupt Endpoint */
	struct usb_host_endpoint *int_ep;
	struct urb *int_urb;
	__u8 *status;
	struct input_dev *input;
	char input_phys[64];

	/* Video Streaming interfaces */
	struct list_head streaming;
};

enum uvc_handle_state {
	UVC_HANDLE_PASSIVE	= 0,
	UVC_HANDLE_ACTIVE	= 1,
};

struct uvc_fh {
	struct uvc_video_device *device;
	enum uvc_handle_state state;
};

struct uvc_driver {
	struct usb_driver driver;

	struct mutex open_mutex;	/* protects from open/disconnect race */

	struct list_head devices;	/* struct uvc_device list */
	struct list_head controls;	/* struct uvc_control_info list */
	struct mutex ctrl_mutex;	/* protects controls and devices
					   lists */
};

/* ------------------------------------------------------------------------
 * Debugging, printing and logging
 */

#define UVC_TRACE_PROBE		(1 << 0)
#define UVC_TRACE_DESCR		(1 << 1)
#define UVC_TRACE_CONTROL	(1 << 2)
#define UVC_TRACE_FORMAT	(1 << 3)
#define UVC_TRACE_CAPTURE	(1 << 4)
#define UVC_TRACE_CALLS		(1 << 5)
#define UVC_TRACE_IOCTL		(1 << 6)
#define UVC_TRACE_FRAME		(1 << 7)
#define UVC_TRACE_SUSPEND	(1 << 8)
#define UVC_TRACE_STATUS	(1 << 9)

#define UVC_WARN_MINMAX		0
#define UVC_WARN_PROBE_DEF	1

extern unsigned int uvc_no_drop_param;
extern unsigned int uvc_trace_param;
extern unsigned int uvc_timeout_param;

#define uvc_trace(flag, msg...) \
	do { \
		if (uvc_trace_param & flag) \
			printk(KERN_DEBUG "uvcvideo: " msg); \
	} while (0)

#define uvc_warn_once(dev, warn, msg...) \
	do { \
		if (!test_and_set_bit(warn, &dev->warnings)) \
			printk(KERN_INFO "uvcvideo: " msg); \
	} while (0)

#define uvc_printk(level, msg...) \
	printk(level "uvcvideo: " msg)

#define UVC_GUID_FORMAT "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-" \
			"%02x%02x%02x%02x%02x%02x"
#define UVC_GUID_ARGS(guid) \
	(guid)[3],  (guid)[2],  (guid)[1],  (guid)[0], \
	(guid)[5],  (guid)[4], \
	(guid)[7],  (guid)[6], \
	(guid)[8],  (guid)[9], \
	(guid)[10], (guid)[11], (guid)[12], \
	(guid)[13], (guid)[14], (guid)[15]

/* --------------------------------------------------------------------------
 * Internal functions.
 */

/* Core driver */
extern struct uvc_driver uvc_driver;
extern void uvc_delete(struct kref *kref);

/* Video buffers queue management. */
extern void uvc_queue_init(struct uvc_video_queue *queue,
		enum v4l2_buf_type type);
extern int uvc_alloc_buffers(struct uvc_video_queue *queue,
		unsigned int nbuffers, unsigned int buflength);
extern int uvc_free_buffers(struct uvc_video_queue *queue);
extern int uvc_query_buffer(struct uvc_video_queue *queue,
		struct v4l2_buffer *v4l2_buf);
extern int uvc_queue_buffer(struct uvc_video_queue *queue,
		struct v4l2_buffer *v4l2_buf);
extern int uvc_dequeue_buffer(struct uvc_video_queue *queue,
		struct v4l2_buffer *v4l2_buf, int nonblocking);
extern int uvc_queue_enable(struct uvc_video_queue *queue, int enable);
extern void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect);
extern struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
		struct uvc_buffer *buf);
extern unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
		struct file *file, poll_table *wait);
extern int uvc_queue_allocated(struct uvc_video_queue *queue);
static inline int uvc_queue_streaming(struct uvc_video_queue *queue)
{
	return queue->flags & UVC_QUEUE_STREAMING;
}

/* V4L2 interface */
extern const struct v4l2_file_operations uvc_fops;

/* Video */
extern int uvc_video_init(struct uvc_video_device *video);
extern int uvc_video_suspend(struct uvc_video_device *video);
extern int uvc_video_resume(struct uvc_video_device *video);
extern int uvc_video_enable(struct uvc_video_device *video, int enable);
extern int uvc_probe_video(struct uvc_video_device *video,
		struct uvc_streaming_control *probe);
extern int uvc_commit_video(struct uvc_video_device *video,
		struct uvc_streaming_control *ctrl);
extern int uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
		__u8 intfnum, __u8 cs, void *data, __u16 size);

/* Status */
extern int uvc_status_init(struct uvc_device *dev);
extern void uvc_status_cleanup(struct uvc_device *dev);
extern int uvc_status_start(struct uvc_device *dev);
extern void uvc_status_stop(struct uvc_device *dev);
extern int uvc_status_suspend(struct uvc_device *dev);
extern int uvc_status_resume(struct uvc_device *dev);

/* Controls */
extern struct uvc_control *uvc_find_control(struct uvc_video_device *video,
		__u32 v4l2_id, struct uvc_control_mapping **mapping);
extern int uvc_query_v4l2_ctrl(struct uvc_video_device *video,
		struct v4l2_queryctrl *v4l2_ctrl);

extern int uvc_ctrl_add_info(struct uvc_control_info *info);
extern int uvc_ctrl_add_mapping(struct uvc_control_mapping *mapping);
extern int uvc_ctrl_init_device(struct uvc_device *dev);
extern void uvc_ctrl_cleanup_device(struct uvc_device *dev);
extern int uvc_ctrl_resume_device(struct uvc_device *dev);
extern void uvc_ctrl_init(void);

extern int uvc_ctrl_begin(struct uvc_video_device *video);
extern int __uvc_ctrl_commit(struct uvc_video_device *video, int rollback);
static inline int uvc_ctrl_commit(struct uvc_video_device *video)
{
	return __uvc_ctrl_commit(video, 0);
}
static inline int uvc_ctrl_rollback(struct uvc_video_device *video)
{
	return __uvc_ctrl_commit(video, 1);
}

extern int uvc_ctrl_get(struct uvc_video_device *video,
		struct v4l2_ext_control *xctrl);
extern int uvc_ctrl_set(struct uvc_video_device *video,
		struct v4l2_ext_control *xctrl);

extern int uvc_xu_ctrl_query(struct uvc_video_device *video,
		struct uvc_xu_control *ctrl, int set);

/* Utility functions */
extern void uvc_simplify_fraction(uint32_t *numerator, uint32_t *denominator,
		unsigned int n_terms, unsigned int threshold);
extern uint32_t uvc_fraction_to_interval(uint32_t numerator,
		uint32_t denominator);
extern struct usb_host_endpoint *uvc_find_endpoint(
		struct usb_host_interface *alts, __u8 epaddr);

/* Quirks support */
void uvc_video_decode_isight(struct urb *urb, struct uvc_video_device *video,
		struct uvc_buffer *buf);

#endif /* __KERNEL__ */

#endif


Makefile:

KERN_DIR = /usr/src/linux-headers-2.6.31-14-generic

all:
	make -C $(KERN_DIR) M=`pwd` modules 

clean:
	make -C $(KERN_DIR) M=`pwd` modules clean
	rm -rf modules.order

obj-m	+= myuvc.o


驅動移植好了，插上攝像頭，執行lsusb就可以看到攝像頭資料，或者在 ls /dev/video0 就是攝像頭驅動的裝置節點，下面我講解開發過程可以選擇的應用程式。

Servfox，Spcaview和luvcview。這三個都可以實現的，我也寫了一個應用程式來測試攝像頭資料，是在LCD上顯示攝像頭資料，首先需要移植好LCD驅動程式。

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