Linux摄像头驱动学习之：（六）UVC-基本框架代码分析
仿照内核的自带UVC（usb video class）驱动程序写的一版简化驱动，仅供学习，实际项目开发中应该尽量使用内核自带的驱动，除非内核自带的驱动不支持此款硬件才需要自己写驱动。
下面就直接上代码了，要根据自己的设备信息修改相关配置参数。
#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" #define sheldon_UVC_URBS 3 /* 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 sheldon_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;
}; /*参考 drivers/media/video/uvc 下一系列代码*/ struct frame_desc {
int width;
int height;
}; /* 参考uvc_video_queue定义一些结构体 */
struct sheldon_uvc_buffer {
struct v4l2_buffer buf;
int state;
int vma_use_count; /* 表示是否已经被mmap */
wait_queue_head_t wait; /* APP要读某个缓冲区,如果无数据,在此休眠 */
struct list_head stream;
struct list_head irq;
}; struct sheldon_uvc_queue {
void *mem;
int count;
int buf_size;
struct sheldon_uvc_buffer buffer[]; struct urb *urb[];
char *urb_buffer[];
dma_addr_t urb_dma[];
unsigned int urb_size; struct list_head mainqueue; /* 供APP消费用 */
struct list_head irqqueue; /* 供底层驱动生产用 */
}; static struct sheldon_uvc_queue sheldon_uvc_queue; static struct video_device *sheldon_uvc_vdev;
static struct usb_device *sheldon_uvc_udev;
static int sheldon_uvc_bEndpointAddress = 0x82; //lsusb - 人工确定参数
static int sheldon_uvc_streaming_intf;
static int sheldon_uvc_control_intf;
static int sheldon_uvc_streaming_bAlternateSetting = ;
static struct v4l2_format sheldon_uvc_format;
static struct frame_desc framdesc[] = {{,},{,},{,}};//{{640, 480}, {352, 288}, {320, 240}, {176, 144}, {160, 120}};
static int frame_idx = ;
static int bBitsPerPixel = ; /* lsusb -v -d 0x1e4e: "bBitsPerPixel" */
static int uvc_version = 0x0100; /* lsusb -v -d 0x1e4e: bcdUVC */
static int wMaxPacketSize = ;
static int ProcessingUnitID = ; static struct sheldon_uvc_streaming_control sheldon_uvc_params; /* A2 参考 uvc_v4l2_do_ioctl */ /* sheldonUV_vidioc_querycap :用于判断是否为视频设备*/
static int sheldonUV_vidioc_querycap(struct file *file, void *priv,
struct v4l2_capability *cap)
{
//strcpy(cap->driver, "sheldonUV");
//strcpy(cap->card, "sheldonUV");
//cap->version = 0x0001;
//cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING; memset(cap, , sizeof *cap);
strcpy(cap->driver, "sheldonUV");
strcpy(cap->card, "sheldonUV"); cap->version = ;
cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING; return ;
} /* A3 列举支持哪种格式
* 参考: uvc_fmts 数组
*/
static int sheldonUV_vidioc_enum_fmt_vid_cap(struct file *file, void *priv,
struct v4l2_fmtdesc *f)
{
/* 人工查看描述符可知我们用的摄像头只支持1种格式 */
if (f->index >= )
return -EINVAL; /* 支持什么格式呢?
* 查看VideoStreaming Interface的描述符,
* 'Y''U''Y''V'
* 得到GUID为"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 ;
} /* A4 返回当前所使用的格式 */
static int sheldonUV_vidioc_get_fmt_vid_cap(struct file *file, void *priv,
struct v4l2_format *f)
{
memcpy(f, &sheldon_uvc_format, sizeof(sheldon_uvc_format));
return ();
} /* A5 测试驱动程序是否支持某种格式 ，强制设置为第一种格式
* 参考: uvc_v4l2_try_format
* sheldon_vivi_vidioc_try_fmt_vid_cap
*/ static int sheldonUV_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; /* 调整format的width, height,
* 计算bytesperline, sizeimage
*/ /* 人工查看描述符, 确定支持哪几种分辨率 */
f->fmt.pix.width = framdesc[frame_idx].width;
f->fmt.pix.height = framdesc[frame_idx].height;
f->fmt.pix.bytesperline =
(f->fmt.pix.width * bBitsPerPixel) >> ;
f->fmt.pix.sizeimage =
f->fmt.pix.height * f->fmt.pix.bytesperline; return ;
} /* A6 如果支持这种格式,则进行设置-参考 vivi_vidioc_s_fmt_vid_cap*/
static int sheldonUV_vidioc_set_fmt_vid_cap(struct file *file, void *priv,
struct v4l2_format *f)
{
int ret = sheldonUV_vidioc_try_fmt_vid_cap(file, NULL, f);
if (ret < )
return ret; memcpy(&sheldon_uvc_format, f, sizeof(sheldon_uvc_format)); return ;// ret;
} static int sheldon_uvc_free_buffers(void)
{
if (sheldon_uvc_queue.mem)
{
vfree(sheldon_uvc_queue.mem);
memset(&sheldon_uvc_queue, , sizeof(sheldon_uvc_queue));
sheldon_uvc_queue.mem = NULL;
}
return ;
} /* A7 APP 调用该ioctl让驱动程分配若干个缓存，APP将从这些缓存中读到视频数据
* 参考: uvc_alloc_buffers
*/
static int sheldonUV_vidioc_reqbufs(struct file *file, void *priv,
struct v4l2_requestbuffers *p)
{
int nbuffers = p->count;
int bufsize = PAGE_ALIGN(sheldon_uvc_format.fmt.pix.sizeimage);
unsigned int i;
void *mem = NULL;
int ret; if ((ret = sheldon_uvc_free_buffers()) < )
goto done; /* Bail out if no buffers should be allocated. */
if (nbuffers == )
goto done; /* Decrement the number of buffers until allocation succeeds. */
for (; nbuffers > ; --nbuffers) {
mem = vmalloc_32(nbuffers * bufsize);
if (mem != NULL)
break;
} if (mem == NULL) {
ret = -ENOMEM;
goto done;
} /* 这些缓存是一次性作为一个整体来分配的 */
memset(&sheldon_uvc_queue, , sizeof(sheldon_uvc_queue)); INIT_LIST_HEAD(&sheldon_uvc_queue.mainqueue);
INIT_LIST_HEAD(&sheldon_uvc_queue.irqqueue); for (i = ; i < nbuffers; ++i) {
sheldon_uvc_queue.buffer[i].buf.index = i;
sheldon_uvc_queue.buffer[i].buf.m.offset = i * bufsize;
sheldon_uvc_queue.buffer[i].buf.length = sheldon_uvc_format.fmt.pix.sizeimage;
sheldon_uvc_queue.buffer[i].buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
sheldon_uvc_queue.buffer[i].buf.sequence = ;
sheldon_uvc_queue.buffer[i].buf.field = V4L2_FIELD_NONE;
sheldon_uvc_queue.buffer[i].buf.memory = V4L2_MEMORY_MMAP;
sheldon_uvc_queue.buffer[i].buf.flags = ;
sheldon_uvc_queue.buffer[i].state = VIDEOBUF_IDLE; //分配好后为空闲状态
init_waitqueue_head(&sheldon_uvc_queue.buffer[i].wait);
} sheldon_uvc_queue.mem = mem;
sheldon_uvc_queue.count = nbuffers;
sheldon_uvc_queue.buf_size = bufsize;
ret = nbuffers; done:
return ret;
} /*A8 查询buffer状态，获得偏移值,app可以调用mmap*/
static int sheldonUV_vidioc_querybuf(struct file *file, void *priv, struct v4l2_buffer *v4l2_buf)
{
int ret = ; if (v4l2_buf->index >= sheldon_uvc_queue.count) {
ret = -EINVAL;
goto done;
} memcpy(v4l2_buf, &sheldon_uvc_queue.buffer[v4l2_buf->index].buf, sizeof(*v4l2_buf)); /* 更新flags */
if (sheldon_uvc_queue.buffer[v4l2_buf->index].vma_use_count)
v4l2_buf->flags |= V4L2_BUF_FLAG_MAPPED; switch (sheldon_uvc_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 把缓冲区放入队列, 底层的硬件操作函数将会把数据放入这个队列的缓存
* 参考: uvc_queue_buffer
*/
static int sheldonUV_vidioc_qbuf(struct file *file, void *priv, struct v4l2_buffer *v4l2_buf)
{
struct sheldon_uvc_buffer *buf; /* 0. APP传入的v4l2_buf可能有问题, 要做判断 */ if (v4l2_buf->type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
v4l2_buf->memory != V4L2_MEMORY_MMAP) {
return -EINVAL;
} if (v4l2_buf->index >= sheldon_uvc_queue.count) {
return -EINVAL;
} buf = &sheldon_uvc_queue.buffer[v4l2_buf->index]; if (buf->state != VIDEOBUF_IDLE) {
return -EINVAL;
} /* 1. 修改状态 */
buf->state = VIDEOBUF_QUEUED;
buf->buf.bytesused = ; /* 2. 放入2个队列 */
/* 队列1: 供APP使用
* 当缓冲区没有数据时,放入mainqueue队列
* 当缓冲区有数据时, APP从mainqueue队列中取出
*/
list_add_tail(&buf->stream, &sheldon_uvc_queue.mainqueue); /* 队列2: 供产生数据的函数使用
* 当采集到数据时,从irqqueue队列中取出第1个缓冲区,存入数据
*/
list_add_tail(&buf->irq, &sheldon_uvc_queue.irqqueue); return ; } static void sheldon_uvc_print_streaming_params(struct sheldon_uvc_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);
} /* 参考: 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 sheldon_uvc_get_streaming_params(struct sheldon_uvc_streaming_control *ctrl)
{
__u8 *data;
__u16 size;
int ret;
__u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
unsigned int pipe; size = uvc_version >= 0x0110 ? : ;
data = kmalloc(size, GFP_KERNEL);
if (data == NULL)
return -ENOMEM; pipe = (GET_CUR & 0x80) ? usb_rcvctrlpipe(sheldon_uvc_udev, )
: usb_sndctrlpipe(sheldon_uvc_udev, );
type |= (GET_CUR & 0x80) ? USB_DIR_IN : USB_DIR_OUT; ret = usb_control_msg(sheldon_uvc_udev, pipe, GET_CUR, type, VS_PROBE_CONTROL << ,
<< | sheldon_uvc_streaming_intf, data, size, ); if (ret < )
goto done; ctrl->bmHint = le16_to_cpup((__le16 *)&data[]);
ctrl->bFormatIndex = data[];
ctrl->bFrameIndex = data[];
ctrl->dwFrameInterval = le32_to_cpup((__le32 *)&data[]);
ctrl->wKeyFrameRate = le16_to_cpup((__le16 *)&data[]);
ctrl->wPFrameRate = le16_to_cpup((__le16 *)&data[]);
ctrl->wCompQuality = le16_to_cpup((__le16 *)&data[]);
ctrl->wCompWindowSize = le16_to_cpup((__le16 *)&data[]);
ctrl->wDelay = le16_to_cpup((__le16 *)&data[]);
ctrl->dwMaxVideoFrameSize = get_unaligned_le32(&data[]);
ctrl->dwMaxPayloadTransferSize = get_unaligned_le32(&data[]); if (size == ) {
ctrl->dwClockFrequency = get_unaligned_le32(&data[]);
ctrl->bmFramingInfo = data[];
ctrl->bPreferedVersion = data[];
ctrl->bMinVersion = data[];
ctrl->bMaxVersion = data[];
} else {
//ctrl->dwClockFrequency = video->dev->clock_frequency;
ctrl->bmFramingInfo = ;
ctrl->bPreferedVersion = ;
ctrl->bMinVersion = ;
ctrl->bMaxVersion = ;
} done:
kfree(data); return (ret < ) ? ret : ;
} /* 参考: uvc_v4l2_try_format ∕uvc_probe_video
* uvc_set_video_ctrl(video, probe, 1)
*/
static int sheldon_uvc_try_streaming_params(struct sheldon_uvc_streaming_control *ctrl)
{
__u8 *data;
__u16 size;
int ret;
__u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
unsigned int pipe; memset(ctrl, , sizeof *ctrl); ctrl->bmHint = ; /* dwFrameInterval */
ctrl->bFormatIndex = ;
ctrl->bFrameIndex = frame_idx + ;
ctrl->dwFrameInterval = ; size = uvc_version >= 0x0110 ? : ;
data = kzalloc(size, GFP_KERNEL); if (data == NULL)
return -ENOMEM; *(__le16 *)&data[] = cpu_to_le16(ctrl->bmHint);
data[] = ctrl->bFormatIndex;
data[] = ctrl->bFrameIndex;
*(__le32 *)&data[] = cpu_to_le32(ctrl->dwFrameInterval);
*(__le16 *)&data[] = cpu_to_le16(ctrl->wKeyFrameRate);
*(__le16 *)&data[] = cpu_to_le16(ctrl->wPFrameRate);
*(__le16 *)&data[] = cpu_to_le16(ctrl->wCompQuality);
*(__le16 *)&data[] = cpu_to_le16(ctrl->wCompWindowSize);
*(__le16 *)&data[] = cpu_to_le16(ctrl->wDelay);
put_unaligned_le32(ctrl->dwMaxVideoFrameSize, &data[]);
put_unaligned_le32(ctrl->dwMaxPayloadTransferSize, &data[]); if (size == ) {
put_unaligned_le32(ctrl->dwClockFrequency, &data[]);
data[] = ctrl->bmFramingInfo;
data[] = ctrl->bPreferedVersion;
data[] = ctrl->bMinVersion;
data[] = ctrl->bMaxVersion;
} pipe = (SET_CUR & 0x80) ? usb_rcvctrlpipe(sheldon_uvc_udev, )
: usb_sndctrlpipe(sheldon_uvc_udev, ); type |= (SET_CUR & 0x80) ? USB_DIR_IN : USB_DIR_OUT; ret = usb_control_msg(sheldon_uvc_udev, pipe, SET_CUR, type, VS_PROBE_CONTROL << ,
<< | sheldon_uvc_streaming_intf, data, size, ); kfree(data); return (ret < ) ? ret : ; } /* 参考: uvc_v4l2_try_format ∕uvc_probe_video
* uvc_set_video_ctrl(video, probe, 1)
*/
static int sheldon_uvc_set_streaming_params(struct sheldon_uvc_streaming_control *ctrl)
{
__u8 *data;
__u16 size;
int ret;
__u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
unsigned int pipe; size = uvc_version >= 0x0110 ? : ;
data = kzalloc(size, GFP_KERNEL);
if (data == NULL)
return -ENOMEM; *(__le16 *)&data[] = cpu_to_le16(ctrl->bmHint);
data[] = ctrl->bFormatIndex;
data[] = ctrl->bFrameIndex;
*(__le32 *)&data[] = cpu_to_le32(ctrl->dwFrameInterval);
*(__le16 *)&data[] = cpu_to_le16(ctrl->wKeyFrameRate);
*(__le16 *)&data[] = cpu_to_le16(ctrl->wPFrameRate);
*(__le16 *)&data[] = cpu_to_le16(ctrl->wCompQuality);
*(__le16 *)&data[] = cpu_to_le16(ctrl->wCompWindowSize);
*(__le16 *)&data[] = cpu_to_le16(ctrl->wDelay);
put_unaligned_le32(ctrl->dwMaxVideoFrameSize, &data[]);
put_unaligned_le32(ctrl->dwMaxPayloadTransferSize, &data[]); if (size == ) {
put_unaligned_le32(ctrl->dwClockFrequency, &data[]);
data[] = ctrl->bmFramingInfo;
data[] = ctrl->bPreferedVersion;
data[] = ctrl->bMinVersion;
data[] = ctrl->bMaxVersion;
} pipe = (SET_CUR & 0x80) ? usb_rcvctrlpipe(sheldon_uvc_udev, )
: usb_sndctrlpipe(sheldon_uvc_udev, );
type |= (SET_CUR & 0x80) ? USB_DIR_IN : USB_DIR_OUT; ret = usb_control_msg(sheldon_uvc_udev, pipe, SET_CUR, type, VS_COMMIT_CONTROL << ,
<< | sheldon_uvc_streaming_intf, data, size, ); kfree(data); return (ret < ) ? ret : ; } static void sheldon_uvc_uninit_urbs(void)
{
int i;
for (i = ; i < sheldon_UVC_URBS; ++i) {
if (sheldon_uvc_queue.urb_buffer[i])
{
usb_buffer_free(sheldon_uvc_udev, sheldon_uvc_queue.urb_size, sheldon_uvc_queue.urb_buffer[i], sheldon_uvc_queue.urb_dma[i]);
sheldon_uvc_queue.urb_buffer[i] = NULL;
} if (sheldon_uvc_queue.urb[i])
{
usb_free_urb(sheldon_uvc_queue.urb[i]);
sheldon_uvc_queue.urb[i] = NULL;
}
}
} /* 参考: uvc_video_complete / uvc_video_decode_isoc */
static void sheldon_uvc_video_complete(struct urb *urb)
{
u8 *src;
u8 *dest;
int ret, i;
int len;
int maxlen;
int nbytes;
struct sheldon_uvc_buffer *buf; switch (urb->status) {
case :
break; default:
printk("Non-zero status (%d) in video "
"completion handler.\n", urb->status);
return;
} /* 从irqqueue队列中取出第1个缓冲区 */
if (!list_empty(&sheldon_uvc_queue.irqqueue)) //如果队列不空
{
buf = list_first_entry(&sheldon_uvc_queue.irqqueue, struct sheldon_uvc_buffer, irq); for (i = ; i < urb->number_of_packets; ++i) {
if (urb->iso_frame_desc[i].status < ) {
printk("USB isochronous frame "
"lost (%d).\n", urb->iso_frame_desc[i].status);
continue;
} src = urb->transfer_buffer + urb->iso_frame_desc[i].offset; //源 dest = sheldon_uvc_queue.mem + buf->buf.m.offset + buf->buf.bytesused; //目的 len = urb->iso_frame_desc[i].actual_length; //整个数据长度
/* 判断数据是否有效 */
/* URB数据含义:
* data[0] : 头部长度
* data[1] : 错误状态
*/
if (len < || src[] < || src[] > len)
continue; /* Skip payloads marked with the error bit ("error frames"). */
if (src[] & UVC_STREAM_ERR) {
printk("Dropping payload (error bit set).\n");
continue;
} /* 除去头部后的数据长度 */
len -= src[]; /* 缓冲区最多还能存多少数据 */
maxlen = buf->buf.length - buf->buf.bytesused;
nbytes = min(len, maxlen); /* 复制数据 */
memcpy(dest, src + src[], nbytes);
buf->buf.bytesused += nbytes; /* 判断一帧数据是否已经全部接收到 */
if (len > maxlen) {
buf->state = VIDEOBUF_DONE;
} /* Mark the buffer as done if the EOF marker is set. */
if (src[] & UVC_STREAM_EOF && buf->buf.bytesused != ) {
printk("Frame complete (EOF found).\n");
if (len == )
printk("EOF in empty payload.\n");
buf->state = VIDEOBUF_DONE;
} } /* 当接收完一帧数据,
* 从irqqueue中删除这个缓冲区
* 唤醒等待数据的进程
*/
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)) < ) {
printk("Failed to resubmit video URB (%d).\n", ret);
}
} /* 参考: uvc_init_video_isoc */
static int sheldon_uvc_alloc_init_urbs(void)
{
u16 psize;
u32 size;
int npackets;
int i;
int j; struct urb *urb; psize = wMaxPacketSize; /* 实时传输端点一次能传输的最大字节数 */
size = sheldon_uvc_params.dwMaxVideoFrameSize; /* 一帧数据的最大长度 */
npackets = DIV_ROUND_UP(size, psize);
if (npackets > )
npackets = ; size = sheldon_uvc_queue.urb_size = psize * npackets; for (i = ; i < sheldon_UVC_URBS; ++i) {
/* 1. 分配usb_buffers */ sheldon_uvc_queue.urb_buffer[i] = usb_buffer_alloc(
sheldon_uvc_udev, size,
GFP_KERNEL | __GFP_NOWARN, &sheldon_uvc_queue.urb_dma[i]); //sheldon_uvc_queue.urb_dma[i]存放分配的物理地址 /* 2. 分配urb */
sheldon_uvc_queue.urb[i] = usb_alloc_urb(npackets, GFP_KERNEL); if (!sheldon_uvc_queue.urb_buffer[i] || !sheldon_uvc_queue.urb[i])
{
sheldon_uvc_uninit_urbs();
return -ENOMEM;
} } /* 3. 设置urb */
for (i = ; i < sheldon_UVC_URBS; ++i) {
urb = sheldon_uvc_queue.urb[i]; urb->dev = sheldon_uvc_udev;
urb->context = NULL;
urb->pipe = usb_rcvisocpipe(sheldon_uvc_udev,sheldon_uvc_bEndpointAddress);
urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
urb->interval = ;
urb->transfer_buffer = sheldon_uvc_queue.urb_buffer[i]; //分配的urb buffer
urb->transfer_dma = sheldon_uvc_queue.urb_dma[i]; //分配的urb 物理地址
urb->complete = sheldon_uvc_video_complete; //收完数据的中断处理函数
urb->number_of_packets = npackets; //要传输的数据次数
urb->transfer_buffer_length = size; //总共的数据量 for (j = ; j < npackets; ++j) {
urb->iso_frame_desc[j].offset = j * psize; //存放每次传输的数据
urb->iso_frame_desc[j].length = psize;
} } return ;
} /*打开视频流
* 参考: uvc_video_enable(video, 1):
* uvc_commit_video
* uvc_init_video
*/
static int sheldonUV_vidioc_streamon(struct file *file, void *priv, enum v4l2_buf_type i)
{
int ret; /* 1. 向USB摄像头设置参数: 比如使用哪个format, 使用这个format下的哪个frame(分辨率)
* 参考: uvc_set_video_ctrl / uvc_get_video_ctrl
* 1.1 根据一个结构体uvc_streaming_control设置数据包: 可以手工设置,也可以读出后再修改
* 1.2 调用usb_control_msg发出数据包
*/ /* a. 测试参数 */
ret = sheldon_uvc_try_streaming_params(&sheldon_uvc_params);
printk("sheldon_uvc_try_streaming_params ret = %d\n", ret); /* b. 取出参数 */
ret = sheldon_uvc_get_streaming_params(&sheldon_uvc_params);
printk("sheldon_uvc_get_streaming_params ret = %d\n", ret); /* c. 设置参数 */
ret = sheldon_uvc_set_streaming_params(&sheldon_uvc_params);
printk("sheldon_uvc_set_streaming_params ret = %d\n", ret); sheldon_uvc_print_streaming_params(&sheldon_uvc_params); /* d. 设置VideoStreaming Interface所使用的setting
* d.1 从sheldon_uvc_params确定带宽
* d.2 根据setting的endpoint能传输的wMaxPacketSize
* 找到能满足该带宽的setting
*/
/* 手工确定:
* bandwidth = sheldon_uvc_params.dwMaxPayloadTransferSize = 64
* 观察lsusb -v -d 0x1e4e:的结果:
* wMaxPacketSize 0x0080 1x128 bytes
* bAlternateSetting 6
*/
usb_set_interface(sheldon_uvc_udev, sheldon_uvc_streaming_intf, sheldon_uvc_streaming_bAlternateSetting); /* 2. 分配设置URB */
ret = sheldon_uvc_alloc_init_urbs();
if (ret)
printk("sheldon_uvc_alloc_init_urbs err : ret = %d\n", ret); /* 3. 提交URB以接收数据 */
for (i = ; i < sheldon_UVC_URBS; ++i) {
if ((ret = usb_submit_urb(sheldon_uvc_queue.urb[i], GFP_KERNEL)) < ) {
printk("Failed to submit URB %u (%d).\n", i, ret);
sheldon_uvc_uninit_urbs();
return ret;
}
} return ;
} /*底层的硬件操作函数取出队列的缓存*/
static int sheldonUV_vidioc_dqbuf(struct file *file, void *priv, struct v4l2_buffer *v4l2_buf)
{
/* APP发现数据就绪后, 从mainqueue里取出这个buffer */ struct sheldon_uvc_buffer *buf;
int ret = ; if (list_empty(&sheldon_uvc_queue.mainqueue)) {
ret = -EINVAL;
goto done;
} buf = list_first_entry(&sheldon_uvc_queue.mainqueue, struct sheldon_uvc_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 之前已经通过mmap映射了缓存, APP可以直接读数据
* A15 再次调用sheldonUV_vidioc_qbuf把缓存放入队列
* A16 poll...
*/ /* A17 停止-关闭视频流
* 参考 : uvc_video_enable(video, 0)
*/ static int sheldonUV_vidioc_streamoff(struct file *file, void *priv, enum v4l2_buf_type t)
{
struct urb *urb;
unsigned int i; /* 1. kill URB */
for (i = ; i < sheldon_UVC_URBS; ++i) {
if ((urb = sheldon_uvc_queue.urb[i]) == NULL)
continue;
usb_kill_urb(urb);
} /* 2. free URB */
sheldon_uvc_uninit_urbs(); /* 3. 设置VideoStreaming Interface为setting 0 */
usb_set_interface(sheldon_uvc_udev, sheldon_uvc_streaming_intf, ); return ;
} /*[下面几个函数实现属性设置]*/ /*
*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 sheldonUV_get_le_value(const __u8 *data)
{
int bits = ;
int offset = ;
__s32 value = ;
__u8 mask; data += offset / ;
offset &= ;
mask = ((1LL << bits) - ) << offset; for (; bits > ; data++) {
__u8 byte = *data & mask;
value |= offset > ? (byte >> offset) : (byte << (-offset));
bits -= - (offset > ? offset : );
offset -= ;
mask = ( << bits) - ;
} /* Sign-extend the value if needed. */
value |= -(value & ( << ( - ))); 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 sheldonUV_set_le_value(__s32 value, __u8 *data)
{
int bits = ;
int offset = ;
__u8 mask; data += offset / ;
offset &= ; for (; bits > ; data++) {
mask = ((1LL << bits) - ) << offset;
*data = (*data & ~mask) | ((value << offset) & mask);
value >>= offset ? offset : ;
bits -= - offset;
offset = ;
}
} /* 参考:uvc_query_v4l2_ctrl:调用VIDIOC_QUERYCTRL ioctl确定是否支持某个属性 */
int sheldonUV_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[]; if (ctrl->id != V4L2_CID_BRIGHTNESS)
return -EINVAL; memset(ctrl, , sizeof *ctrl);
ctrl->id = V4L2_CID_BRIGHTNESS;
ctrl->type = V4L2_CTRL_TYPE_INTEGER;
strcpy(ctrl->name, "sheldonUV_BRIGHTNESS");
ctrl->flags = ; pipe = usb_rcvctrlpipe(sheldon_uvc_udev, );
type |= USB_DIR_IN; /* 发起USB传输确定这些值 */
ret = usb_control_msg(sheldon_uvc_udev, pipe, GET_MIN, type, PU_BRIGHTNESS_CONTROL << ,
ProcessingUnitID << | sheldon_uvc_control_intf, data, , );
if (ret != )
return -EIO;
ctrl->minimum = sheldonUV_get_le_value(data); /* Note signedness */ ret = usb_control_msg(sheldon_uvc_udev, pipe, GET_MAX, type, PU_BRIGHTNESS_CONTROL << ,
ProcessingUnitID << | sheldon_uvc_control_intf, data, , );
if (ret != )
return -EIO;
ctrl->maximum = sheldonUV_get_le_value(data); /* Note signedness */ ret = usb_control_msg(sheldon_uvc_udev, pipe, GET_RES, type, PU_BRIGHTNESS_CONTROL << ,
ProcessingUnitID << | sheldon_uvc_control_intf, data, , );
if (ret != )
return -EIO;
ctrl->step = sheldonUV_get_le_value(data); /* Note signedness */ ret = usb_control_msg(sheldon_uvc_udev, pipe, GET_DEF, type, PU_BRIGHTNESS_CONTROL << ,
ProcessingUnitID << | sheldon_uvc_control_intf, data, , );
if (ret != )
return -EIO;
ctrl->default_value = sheldonUV_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 ;
} /* 参考 : uvc_ctrl_get : 获得属性 */
int sheldonUV_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[]; if (ctrl->id != V4L2_CID_BRIGHTNESS)
return -EINVAL; pipe = usb_rcvctrlpipe(sheldon_uvc_udev, );
type |= USB_DIR_IN; ret = usb_control_msg(sheldon_uvc_udev, pipe, GET_CUR, type, PU_BRIGHTNESS_CONTROL << ,
ProcessingUnitID << | sheldon_uvc_control_intf, data, , );
if (ret != )
return -EIO;
ctrl->value = sheldonUV_get_le_value(data); /* Note signedness */ return ;
} /* 参考: uvc_ctrl_set/uvc_ctrl_commit : 设置属性*/
int sheldonUV_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[]; if (ctrl->id != V4L2_CID_BRIGHTNESS)
return -EINVAL; sheldonUV_set_le_value(ctrl->value, data); pipe = usb_sndctrlpipe(sheldon_uvc_udev, );
type |= USB_DIR_OUT; ret = usb_control_msg(sheldon_uvc_udev, pipe, SET_CUR, type, PU_BRIGHTNESS_CONTROL << ,
ProcessingUnitID << | sheldon_uvc_control_intf, data, , );
if (ret != )
return -EIO; return ;
} static const struct v4l2_ioctl_ops sheldonUV_ioctl_ops = {
// 表示它是一个摄像头设备
.vidioc_querycap = sheldonUV_vidioc_querycap, /* 用于列举、获得、测试、设置摄像头的数据的格式 */
.vidioc_enum_fmt_vid_cap = sheldonUV_vidioc_enum_fmt_vid_cap,
.vidioc_g_fmt_vid_cap = sheldonUV_vidioc_get_fmt_vid_cap,
.vidioc_try_fmt_vid_cap = sheldonUV_vidioc_try_fmt_vid_cap,
.vidioc_s_fmt_vid_cap = sheldonUV_vidioc_set_fmt_vid_cap, /* 缓冲区操作: 申请/查询/放入队列/取出队列 */
.vidioc_reqbufs = sheldonUV_vidioc_reqbufs,
.vidioc_querybuf = sheldonUV_vidioc_querybuf,
.vidioc_qbuf = sheldonUV_vidioc_qbuf,
.vidioc_dqbuf = sheldonUV_vidioc_dqbuf, /* 查询/获得/设置属性 */
.vidioc_queryctrl = sheldonUV_vidioc_queryctrl,
.vidioc_g_ctrl = sheldonUV_vidioc_g_ctrl,
.vidioc_s_ctrl = sheldonUV_vidioc_s_ctrl, // 启动/停止
.vidioc_streamon = sheldonUV_vidioc_streamon,
.vidioc_streamoff = sheldonUV_vidioc_streamoff,
}; static int sheldonUV_open(struct file *file)
{
/* 队列操作2: 初始化 */
/* videobuf_queue_vmalloc_init(&sheldonUV_vb_vidqueue, &sheldonUV_video_qops,
NULL, &sheldonUV_queue_slock, V4L2_BUF_TYPE_VIDEO_CAPTURE, V4L2_FIELD_INTERLACED,
sizeof(struct videobuf_buffer), NULL); // 倒数第2个参数是buffer的头部大小 sheldonUV_timer.expires = jiffies + 1;
add_timer(&sheldonUV_timer);
*/
return ;
} static void sheldon_uvc_vm_open(struct vm_area_struct *vma)
{
struct sheldon_uvc_buffer *buffer = vma->vm_private_data;
buffer->vma_use_count++;
} static void sheldon_uvc_vm_close(struct vm_area_struct *vma)
{
struct sheldon_uvc_buffer *buffer = vma->vm_private_data;
buffer->vma_use_count--;
} static struct vm_operations_struct sheldon_uvc_vm_ops = {
.open = sheldon_uvc_vm_open,
.close = sheldon_uvc_vm_close,
}; /*映射->应用程序空间,之后app可以直接操作这块
* 参考: uvc_v4l2_mmap
*/
static int sheldonUV_mmap(struct file *file, struct vm_area_struct *vma)
{
struct sheldon_uvc_buffer *buffer;
struct page *page;
unsigned long addr, start, size;
unsigned int i;
int ret = ; start = vma->vm_start;
size = vma->vm_end - vma->vm_start; /* 应用程序调用mmap函数时, 会传入offset参数
* 根据这个offset找出指定的缓冲区
*/
for (i = ; i < sheldon_uvc_queue.count; ++i) {
buffer = &sheldon_uvc_queue.buffer[i];
if ((buffer->buf.m.offset >> PAGE_SHIFT) == vma->vm_pgoff)
break;
} if (i == sheldon_uvc_queue.count || size != sheldon_uvc_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; /* 根据虚拟地址找到缓冲区对应的page构体 */
addr = (unsigned long)sheldon_uvc_queue.mem + buffer->buf.m.offset;
while (size > ) {
page = vmalloc_to_page((void *)addr); /* 把此page映射到APP对应的虚拟地址上面 */
if ((ret = vm_insert_page(vma, start, page)) < )
goto done; start += PAGE_SIZE;
addr += PAGE_SIZE;
size -= PAGE_SIZE;
} vma->vm_ops = &sheldon_uvc_vm_ops;
vma->vm_private_data = buffer;
sheldon_uvc_vm_open(vma); done:
return ret;
} /*APP 调用POLL/select确定缓存数据是否就绪*/
static unsigned int sheldonUV_poll(struct file *file, struct poll_table_struct *wait)
{
struct sheldon_uvc_buffer *buf;
unsigned int mask = ; /* 从mainqueuq中取出第1个缓冲区 */ /*判断它的状态, 如果未就绪, 休眠 */ if (list_empty(&sheldon_uvc_queue.mainqueue)) {
mask |= POLLERR;
goto done;
} buf = list_first_entry(&sheldon_uvc_queue.mainqueue, struct sheldon_uvc_buffer, stream); poll_wait(file, &buf->wait, wait);
if (buf->state == VIDEOBUF_DONE ||
buf->state == VIDEOBUF_ERROR)
mask |= POLLIN | POLLRDNORM; done:
return mask;
} static int sheldonUV_close(struct file *file)
{
//del_timer(&sheldonUV_timer);
//videobuf_stop(&sheldonUV_vb_vidqueue);
//videobuf_mmap_free(&sheldonUV_vb_vidqueue); return ;
} static const struct v4l2_file_operations sheldonUV_fops = {
.owner = THIS_MODULE,
.open = sheldonUV_open,
.release = sheldonUV_close,
.mmap = sheldonUV_mmap,
.ioctl = video_ioctl2, /* V4L2 ioctl handler -> sheldonUV_ioctl_ops*/
.poll = sheldonUV_poll,
}; static void sheldonUV_release(struct video_device *vdev)
{
} //probe处理函数，有匹配usb设备时调用
static int sheldon_uvc_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
static int cnt; //根据interface结构体获得usb_devce结构体，其中包含了设备描述符
struct usb_device *dev = interface_to_usbdev(intf);
//此处需要定义一个描述符结构体
struct usb_device_descriptor *descriptor = &dev->descriptor;
//从usb_device结构体中获得配置描述符相关信息
struct usb_host_config *host_config;
struct usb_config_descriptor *config;
//定义接口联合体描述符结构体,获得 IAD 接口
struct usb_interface_assoc_descriptor *assoc_desc;
//接口描述符
struct usb_interface_descriptor *interface;
//端点描述符
struct usb_endpoint_descriptor *endpoint;
//定义接口设置信息结构体
//struct usb_interface_descriptor *idesc; int i, j ,k ,l ,m;
unsigned char *buffer;
int buflen; int desc_len;
//int desc_cnt; sheldon_uvc_udev = dev; printk("sheldn_uvc_probe : cnt = %d\n", cnt++); if (cnt == )
{
sheldon_uvc_control_intf = intf->cur_altsetting->desc.bInterfaceNumber;
}
else if(cnt == )
{
sheldon_uvc_streaming_intf = intf->cur_altsetting->desc.bInterfaceNumber;
} if (cnt == )
{
/*1.分配一个video_device结构体*/
sheldon_uvc_vdev = video_device_alloc();
/*2.设置*/
/* 2.1 */
sheldon_uvc_vdev->release = sheldonUV_release; /* 2.2 */
sheldon_uvc_vdev->fops = &sheldonUV_fops; /* 2.3 */
sheldon_uvc_vdev->ioctl_ops = &sheldonUV_ioctl_ops;
/*3.注册*/
video_register_device(sheldon_uvc_vdev ,VFL_TYPE_GRABBER, -);
} return ;
} //disconnect函数，设备断开时调用
static void sheldon_uvc_disconnect(struct usb_interface *intf)
{
static int cnt;
printk("sheldon_uvc_disconnect : cnt = %d\n",cnt++); if (cnt == )
{
video_unregister_device(sheldon_uvc_vdev);
video_device_release(sheldon_uvc_vdev);
} } //支持的设备类型信息
static struct usb_device_id sheldon_uvc_ids[] = {
/* Generic USB Video Class */
{ USB_INTERFACE_INFO(USB_CLASS_VIDEO, , ) },/*1-视频控制接口*/
{ USB_INTERFACE_INFO(USB_CLASS_VIDEO, , ) },/*2-视频流控制接口(被1包含)*/
{}
}; //1.分配usb_driver结构体
//2.设置 static struct usb_driver sheldon_uvc_driver = {
.name = "sheldon_UV",
.probe = sheldon_uvc_probe,
.disconnect = sheldon_uvc_disconnect,
.id_table = sheldon_uvc_ids,
}; static int sheldon_uvc_init(void)
{
//3.注册
printk("sheldon_uvc_init ~\n");
usb_register(&sheldon_uvc_driver);
return ;
} static void sheldon_uvc_exit(void)
{
printk("sheldon_uvc_exit ~\n");
usb_deregister(&sheldon_uvc_driver);
} module_init(sheldon_uvc_init);
module_exit(sheldon_uvc_exit);
MODULE_LICENSE("GPL");
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