发布:[03-1]_回顾与编写驱动框架,[03-2]_虚拟摄像头驱动编程_ioctl代码,[03-3]_虚拟摄像头驱动编程_buffer代码

IMX6ULL/doc_pic/13_V4L2/02_V4L2驱动程序框架.md

@@ -508,7 +508,3 @@ APP ioctl VIDIOC_DQBUF
 
 
 
-
-
-## 2. 从0编写一个虚拟的摄像头驱动
-

IMX6ULL/doc_pic/13_V4L2/03_从0编写一个虚拟摄像头驱动.md

@@ -0,0 +1,102 @@
+# 从0编写一个虚拟摄像头驱动 #
+
+参考资料：
+
+* 深入理解linux内核v4l2框架之videobuf2：https://blog.csdn.net/yyjsword/article/details/9243717
+* V4L2框架-videobuf2：https://blog.csdn.net/u013904227/article/details/81054611
+
+
+
+## 1. 回顾与编写程序框架
+
+本节视频对应的代码：
+
+```shell
+doc_and_source_for_drivers\
+	IMX6ULL\source\
+		13_V4L2\
+			06_virtual_driver\
+				01_virtual_driver_framework
+```
+
+
+
+参考《1.3.2 videobuffer2的3个ops》里面完整的注册流程。
+
+完整的注册流程(参考`drivers\media\usb\airspy\airspy.c`)：
+
+```shell
+static struct video_device airspy_template = {
+	.name                     = "AirSpy SDR",
+	.release                  = video_device_release_empty,
+	.fops                     = &airspy_fops,
+	.ioctl_ops                = &airspy_ioctl_ops,
+};
+
+/* 构造一个vb2_queue */
+	/* Init videobuf2 queue structure */
+	s->vb_queue.type = V4L2_BUF_TYPE_SDR_CAPTURE;
+	s->vb_queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
+	s->vb_queue.drv_priv = s;
+	s->vb_queue.buf_struct_size = sizeof(struct airspy_frame_buf);
+	s->vb_queue.ops = &airspy_vb2_ops;          // vb2_ops, 硬件相关的操作函数
+	s->vb_queue.mem_ops = &vb2_vmalloc_memops;  // vb2_mem_ops, 辅助结构体,用于mem ops(alloc、mmap)
+	s->vb_queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	ret = vb2_queue_init(&s->vb_queue);
+				q->buf_ops = &v4l2_buf_ops;    // vb2_buf_ops, 用于APP和驱动传递参数
+
+// 分配/设置video_device结构体
+s->vdev = airspy_template;
+s->vdev.queue = &s->vb_queue;    // 指向前面构造的vb2_queue
+
+// 初始化一个v4l2_device结构体(起辅助作用)
+/* Register the v4l2_device structure */
+s->v4l2_dev.release = airspy_video_release;
+ret = v4l2_device_register(&intf->dev, &s->v4l2_dev);
+
+// video_device和4l2_device建立联系
+s->vdev.v4l2_dev = &s->v4l2_dev;
+
+// 注册video_device结构体
+ret = video_register_device(&s->vdev, VFL_TYPE_SDR, -1);
+		__video_register_device
+			// 根据次设备号把video_device结构体放入数组
+			video_device[vdev->minor] = vdev;
+			
+			// 注册字符设备驱动程序
+			vdev->cdev->ops = &v4l2_fops;
+			vdev->cdev->owner = owner;
+			ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
+
+```
+
+
+
+## 2. 编写硬件相关代码
+
+本节视频对应的代码：
+
+```shell
+doc_and_source_for_drivers\
+	IMX6ULL\source\
+		13_V4L2\
+			06_virtual_driver\
+				02_virtual_driver_hardware
+```
+
+### 2.1 ioctl相关的代码
+
+
+
+### 2.2 buffer相关的代码
+
+
+
+### 2.3 数据传输
+
+
+
+## 3. 上机测试
+
+
+

IMX6ULL/source/13_V4L2/06_virtual_driver/01_virtual_driver_framework/virtual_video_drv.c

@@ -0,0 +1,128 @@
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-event.h>
+#include <media/videobuf2-v4l2.h>
+#include <media/videobuf2-vmalloc.h>
+
+static const struct v4l2_file_operations virtual_fops = {
+	.owner                    = THIS_MODULE,
+	.open                     = v4l2_fh_open,
+	.release                  = vb2_fop_release,
+	.read                     = vb2_fop_read,
+	.poll                     = vb2_fop_poll,
+	.mmap                     = vb2_fop_mmap,
+	.unlocked_ioctl           = video_ioctl2,
+};
+
+static const struct v4l2_ioctl_ops virtual_ioctl_ops = {
+	.vidioc_querycap          = airspy_querycap,
+
+	.vidioc_enum_fmt_sdr_cap  = airspy_enum_fmt_sdr_cap,
+	.vidioc_g_fmt_sdr_cap     = airspy_g_fmt_sdr_cap,
+	.vidioc_s_fmt_sdr_cap     = airspy_s_fmt_sdr_cap,
+	.vidioc_try_fmt_sdr_cap   = airspy_try_fmt_sdr_cap,
+
+	.vidioc_reqbufs           = vb2_ioctl_reqbufs,
+	.vidioc_create_bufs       = vb2_ioctl_create_bufs,
+	.vidioc_prepare_buf       = vb2_ioctl_prepare_buf,
+	.vidioc_querybuf          = vb2_ioctl_querybuf,
+	.vidioc_qbuf              = vb2_ioctl_qbuf,
+	.vidioc_dqbuf             = vb2_ioctl_dqbuf,
+
+	.vidioc_streamon          = vb2_ioctl_streamon,
+	.vidioc_streamoff         = vb2_ioctl_streamoff,
+
+	.vidioc_g_tuner           = airspy_g_tuner,
+	.vidioc_s_tuner           = airspy_s_tuner,
+
+	.vidioc_g_frequency       = airspy_g_frequency,
+	.vidioc_s_frequency       = airspy_s_frequency,
+	.vidioc_enum_freq_bands   = airspy_enum_freq_bands,
+
+	.vidioc_subscribe_event   = v4l2_ctrl_subscribe_event,
+	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
+	.vidioc_log_status        = v4l2_ctrl_log_status,
+};
+
+static struct video_device g_vdev = {
+	.name                     = "100ask_virtual_video",
+	.release                  = video_device_release_empty,
+	.fops                     = &virtual_fops,
+	.ioctl_ops                = &virtual_ioctl_ops,
+};
+static struct v4l2_device g_v4l2_dev;
+
+static struct vb2_queue g_vb_queue;
+
+static const struct vb2_ops virtul_vb2_ops = {
+	.queue_setup            = airspy_queue_setup,
+	.buf_queue              = airspy_buf_queue,
+	.start_streaming        = airspy_start_streaming,
+	.stop_streaming         = airspy_stop_streaming,
+	.wait_prepare           = vb2_ops_wait_prepare,
+	.wait_finish            = vb2_ops_wait_finish,
+};
+
+
+static int virtual_video_drv_init(void)
+{
+    int ret;
+    
+    /* 分配/设置/注册video_device */
+
+    /* 设置
+     * 1. 函数调用(比如ioctl)
+     * 2. 队列/buffer的管理
+     */
+
+    g_vb_queue.type = V4L2_BUF_TYPE_SDR_CAPTURE;
+    g_vb_queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
+    g_vb_queue.drv_priv = NULL;
+    g_vb_queue.buf_struct_size = sizeof(struct airspy_frame_buf);
+    g_vb_queue.ops = &virtul_vb2_ops;
+    g_vb_queue.mem_ops = &vb2_vmalloc_memops;
+    g_vb_queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	ret = vb2_queue_init(&s->vb_queue);
+	if (ret) {
+		printk("Could not initialize vb2 queue\n");
+		return -1;;
+	}
+
+    g_vdev.queue = &g_vb_queue;     
+    g_vdev.queue->lock = &s->vb_queue_lock;
+
+	/* Register the v4l2_device structure(辅助作用) */
+	g_v4l2_dev.release = airspy_video_release;
+	ret = v4l2_device_register(NULL, &g_v4l2_dev);
+	if (ret) {
+		printk("Failed to register v4l2-device (%d)\n", ret);
+		return -1;
+	}
+	g_vdev.v4l2_dev = &g_v4l2_dev;
+	g_vdev.lock = &s->v4l2_lock;
+
+	ret = video_register_device(&g_vdev, VFL_TYPE_SDR, -1);
+	if (ret) {
+		printk("Failed to register as video device (%d)\n", ret);
+		return -1;
+	}
+    return 0;
+}
+
+static void virtual_video_drv_exit(void)
+{
+    /* 反注册/释放video_device */
+    v4l2_device_unregister(&g_v4l2_dev);
+    video_unregister_device(&g_vdev);
+}
+
+module_init(virtual_video_drv_init);
+module_exit(virtual_video_drv_exit);
+
+MODULE_LICENSE("GPL");
+
+

IMX6ULL/source/13_V4L2/06_virtual_driver/02_virtual_driver_hardware/virtual_video_drv.c

@@ -0,0 +1,227 @@
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-event.h>
+#include <media/videobuf2-v4l2.h>
+#include <media/videobuf2-vmalloc.h>
+
+static struct list_head g_queued_bufs;
+
+/* intermediate buffers with raw data from the USB device */
+struct virtual_frame_buf {
+	/* common v4l buffer stuff -- must be first */
+	struct vb2_v4l2_buffer vb;
+	struct list_head list;
+};
+
+static int virtual_querycap(struct file *file, void *fh,
+		struct v4l2_capability *cap)
+{
+	strlcpy(cap->driver, "100ask_virtual_video", sizeof(cap->driver));
+	strlcpy(cap->card, "no-card", sizeof(cap->card));
+	cap->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING | V4L2_CAP_READWRITE ;
+	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
+
+	return 0;
+}
+
+static int virtual_enum_fmt_cap(struct file *file, void *priv,
+        struct v4l2_fmtdesc *f)
+{
+    if (f->index > 0)
+        return -EINVAL;
+
+    strlcpy(f->description, "100ask motion jpeg", sizeof(f->description));
+    f->pixelformat = V4L2_PIX_FMT_MJPEG;
+
+    return 0;
+}
+
+        
+static int virtual_s_fmt_cap(struct file *file, void *priv,
+        struct v4l2_format *f)
+{
+    /* 分辨用户传入的参数是否可用
+     * 如果不可用, 给APP提供最接近的、硬件支持的参数
+     */
+
+    if (f.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+        return -EINVAL;
+    if (f.fmt.pix.pixelformat != V4L2_PIX_FMT_MJPEG)
+        return -EINVAL;
+    
+    f.fmt.pix.width = 800;
+    f.fmt.pix.height = 600;
+
+    return 0;
+}
+
+static int virtual_enum_framesizes(struct file *file, void *fh,
+                     struct v4l2_frmsizeenum *fsize)
+{
+    if (fsize->index > 0)
+        return -EINVAL;
+
+    fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
+    fsize->discrete.width = 800;
+    fsize->discrete.height = 600;
+    return 0;
+}
+
+
+static const struct v4l2_file_operations virtual_fops = {
+	.owner                    = THIS_MODULE,
+	.open                     = v4l2_fh_open,
+	.release                  = vb2_fop_release,
+	.read                     = vb2_fop_read,
+	.poll                     = vb2_fop_poll,
+	.mmap                     = vb2_fop_mmap,
+	.unlocked_ioctl           = video_ioctl2,
+};
+
+static const struct v4l2_ioctl_ops virtual_ioctl_ops = {
+	.vidioc_querycap          = virtual_querycap,
+
+	.vidioc_enum_fmt_vid_cap  = virtual_enum_fmt_cap,
+	.vidioc_s_fmt_vid_cap     = virtual_s_fmt_cap,
+	.vidioc_enum_framesizes   = virtual_enum_framesizes,
+
+	.vidioc_reqbufs           = vb2_ioctl_reqbufs,
+	.vidioc_create_bufs       = vb2_ioctl_create_bufs,
+	.vidioc_prepare_buf       = vb2_ioctl_prepare_buf,
+	.vidioc_querybuf          = vb2_ioctl_querybuf,
+	.vidioc_qbuf              = vb2_ioctl_qbuf,
+	.vidioc_dqbuf             = vb2_ioctl_dqbuf,
+
+	.vidioc_streamon          = vb2_ioctl_streamon,
+	.vidioc_streamoff         = vb2_ioctl_streamoff,
+};
+
+static struct video_device g_vdev = {
+	.name                     = "100ask_virtual_video",
+	.release                  = video_device_release_empty,
+	.fops                     = &virtual_fops,
+	.ioctl_ops                = &virtual_ioctl_ops,
+};
+static struct v4l2_device g_v4l2_dev;
+
+static struct vb2_queue g_vb_queue;
+
+/* Videobuf2 operations */
+static int virtual_queue_setup(struct vb2_queue *vq,
+		unsigned int *nbuffers,
+		unsigned int *nplanes, unsigned int sizes[], struct device *alloc_devs[])
+{
+    /* 假装:至少需要8个buffer, 每个buffer只有1个plane */
+
+	/* Need at least 8 buffers */
+	if (vq->num_buffers + *nbuffers < 8)
+		*nbuffers = 8 - vq->num_buffers;
+	*nplanes = 1;
+	sizes[0] = PAGE_ALIGN(800*600*2);
+
+	return 0;
+}
+
+        
+static void virtual_buf_queue(struct vb2_buffer *vb)
+{
+
+    /* 把这个buffer告诉硬件相关的驱动程序 */
+
+    struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
+    struct virtual_frame_buf *buf =
+            container_of(vbuf, struct virtual_frame_buf, vb);
+    unsigned long flags;
+
+    //spin_lock_irqsave(&s->queued_bufs_lock, flags);
+    list_add_tail(&buf->list, &g_queued_bufs);
+    //spin_unlock_irqrestore(&s->queued_bufs_lock, flags);
+}
+
+static int virtual_start_streaming(struct vb2_queue *vq, unsigned int count)
+{
+    /* 启动硬件传输 */
+    return 0;
+}
+
+static void virtual_stop_streaming(struct vb2_queue *vq)
+{
+    /* 停止硬件传输 */
+}
+
+
+static const struct vb2_ops virtul_vb2_ops = {
+	.queue_setup            = virtual_queue_setup,
+	.buf_queue              = virtual_buf_queue,
+	.start_streaming        = virtual_start_streaming,
+	.stop_streaming         = virtual_stop_streaming,
+	.wait_prepare           = vb2_ops_wait_prepare,
+	.wait_finish            = vb2_ops_wait_finish,
+};
+
+
+static int virtual_video_drv_init(void)
+{
+    int ret;
+    
+    /* 分配/设置/注册video_device */
+
+    /* 设置
+     * 1. 函数调用(比如ioctl)
+     * 2. 队列/buffer的管理
+     */
+
+    g_vb_queue.type = V4L2_BUF_TYPE_SDR_CAPTURE;
+    g_vb_queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
+    g_vb_queue.drv_priv = NULL;
+    g_vb_queue.buf_struct_size = sizeof(struct virtual_frame_buf);  /* 分配vb时, 分配的空间大小为buf_struct_size */
+    g_vb_queue.ops = &virtul_vb2_ops;
+    g_vb_queue.mem_ops = &vb2_vmalloc_memops;
+    g_vb_queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	ret = vb2_queue_init(&s->vb_queue);
+	if (ret) {
+		printk("Could not initialize vb2 queue\n");
+		return -1;;
+	}
+
+    g_vdev.queue = &g_vb_queue;     
+    g_vdev.queue->lock = &s->vb_queue_lock;
+
+	/* Register the v4l2_device structure(辅助作用) */
+	g_v4l2_dev.release = airspy_video_release;
+	ret = v4l2_device_register(NULL, &g_v4l2_dev);
+	if (ret) {
+		printk("Failed to register v4l2-device (%d)\n", ret);
+		return -1;
+	}
+	g_vdev.v4l2_dev = &g_v4l2_dev;
+	g_vdev.lock = &s->v4l2_lock;
+
+	ret = video_register_device(&g_vdev, VFL_TYPE_SDR, -1);
+	if (ret) {
+		printk("Failed to register as video device (%d)\n", ret);
+		return -1;
+	}
+
+	INIT_LIST_HEAD(&g_queued_bufs);
+    
+    return 0;
+}
+
+static void virtual_video_drv_exit(void)
+{
+    /* 反注册/释放video_device */
+    v4l2_device_unregister(&g_v4l2_dev);
+    video_unregister_device(&g_vdev);
+}
+
+module_init(virtual_video_drv_init);
+module_exit(virtual_video_drv_exit);
+
+MODULE_LICENSE("GPL");
+
+

README.md

@@ -809,6 +809,14 @@ git clone https://e.coding.net/weidongshan/linux/doc_and_source_for_drivers.git
   [02-5]_videobuffer2情景分析
   ```
 
+* 2023.09.04 发布"摄像头驱动"
+
+  ```shell
+  [03-1]_回顾与编写驱动框架
+  [03-2]_虚拟摄像头驱动编程_ioctl代码
+  [03-3]_虚拟摄像头驱动编程_buffer代码
+  ```
+
   
 
 

STM32MP157/doc_pic/13_V4L2/02_V4L2驱动程序框架.md

@@ -508,7 +508,3 @@ APP ioctl VIDIOC_DQBUF
 
 
 
-
-
-## 2. 从0编写一个虚拟的摄像头驱动
-

STM32MP157/doc_pic/13_V4L2/03_从0编写一个虚拟摄像头驱动.md

@@ -0,0 +1,102 @@
+# 从0编写一个虚拟摄像头驱动 #
+
+参考资料：
+
+* 深入理解linux内核v4l2框架之videobuf2：https://blog.csdn.net/yyjsword/article/details/9243717
+* V4L2框架-videobuf2：https://blog.csdn.net/u013904227/article/details/81054611
+
+
+
+## 1. 回顾与编写程序框架
+
+本节视频对应的代码：
+
+```shell
+doc_and_source_for_drivers\
+	IMX6ULL\source\
+		13_V4L2\
+			06_virtual_driver\
+				01_virtual_driver_framework
+```
+
+
+
+参考《1.3.2 videobuffer2的3个ops》里面完整的注册流程。
+
+完整的注册流程(参考`drivers\media\usb\airspy\airspy.c`)：
+
+```shell
+static struct video_device airspy_template = {
+	.name                     = "AirSpy SDR",
+	.release                  = video_device_release_empty,
+	.fops                     = &airspy_fops,
+	.ioctl_ops                = &airspy_ioctl_ops,
+};
+
+/* 构造一个vb2_queue */
+	/* Init videobuf2 queue structure */
+	s->vb_queue.type = V4L2_BUF_TYPE_SDR_CAPTURE;
+	s->vb_queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
+	s->vb_queue.drv_priv = s;
+	s->vb_queue.buf_struct_size = sizeof(struct airspy_frame_buf);
+	s->vb_queue.ops = &airspy_vb2_ops;          // vb2_ops, 硬件相关的操作函数
+	s->vb_queue.mem_ops = &vb2_vmalloc_memops;  // vb2_mem_ops, 辅助结构体,用于mem ops(alloc、mmap)
+	s->vb_queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	ret = vb2_queue_init(&s->vb_queue);
+				q->buf_ops = &v4l2_buf_ops;    // vb2_buf_ops, 用于APP和驱动传递参数
+
+// 分配/设置video_device结构体
+s->vdev = airspy_template;
+s->vdev.queue = &s->vb_queue;    // 指向前面构造的vb2_queue
+
+// 初始化一个v4l2_device结构体(起辅助作用)
+/* Register the v4l2_device structure */
+s->v4l2_dev.release = airspy_video_release;
+ret = v4l2_device_register(&intf->dev, &s->v4l2_dev);
+
+// video_device和4l2_device建立联系
+s->vdev.v4l2_dev = &s->v4l2_dev;
+
+// 注册video_device结构体
+ret = video_register_device(&s->vdev, VFL_TYPE_SDR, -1);
+		__video_register_device
+			// 根据次设备号把video_device结构体放入数组
+			video_device[vdev->minor] = vdev;
+			
+			// 注册字符设备驱动程序
+			vdev->cdev->ops = &v4l2_fops;
+			vdev->cdev->owner = owner;
+			ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
+
+```
+
+
+
+## 2. 编写硬件相关代码
+
+本节视频对应的代码：
+
+```shell
+doc_and_source_for_drivers\
+	IMX6ULL\source\
+		13_V4L2\
+			06_virtual_driver\
+				02_virtual_driver_hardware
+```
+
+### 2.1 ioctl相关的代码
+
+
+
+### 2.2 buffer相关的代码
+
+
+
+### 2.3 数据传输
+
+
+
+## 3. 上机测试
+
+
+

STM32MP157/source/A7/13_V4L2/06_virtual_driver/01_virtual_driver_framework/virtual_video_drv.c

@@ -0,0 +1,128 @@
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-event.h>
+#include <media/videobuf2-v4l2.h>
+#include <media/videobuf2-vmalloc.h>
+
+static const struct v4l2_file_operations virtual_fops = {
+	.owner                    = THIS_MODULE,
+	.open                     = v4l2_fh_open,
+	.release                  = vb2_fop_release,
+	.read                     = vb2_fop_read,
+	.poll                     = vb2_fop_poll,
+	.mmap                     = vb2_fop_mmap,
+	.unlocked_ioctl           = video_ioctl2,
+};
+
+static const struct v4l2_ioctl_ops virtual_ioctl_ops = {
+	.vidioc_querycap          = airspy_querycap,
+
+	.vidioc_enum_fmt_sdr_cap  = airspy_enum_fmt_sdr_cap,
+	.vidioc_g_fmt_sdr_cap     = airspy_g_fmt_sdr_cap,
+	.vidioc_s_fmt_sdr_cap     = airspy_s_fmt_sdr_cap,
+	.vidioc_try_fmt_sdr_cap   = airspy_try_fmt_sdr_cap,
+
+	.vidioc_reqbufs           = vb2_ioctl_reqbufs,
+	.vidioc_create_bufs       = vb2_ioctl_create_bufs,
+	.vidioc_prepare_buf       = vb2_ioctl_prepare_buf,
+	.vidioc_querybuf          = vb2_ioctl_querybuf,
+	.vidioc_qbuf              = vb2_ioctl_qbuf,
+	.vidioc_dqbuf             = vb2_ioctl_dqbuf,
+
+	.vidioc_streamon          = vb2_ioctl_streamon,
+	.vidioc_streamoff         = vb2_ioctl_streamoff,
+
+	.vidioc_g_tuner           = airspy_g_tuner,
+	.vidioc_s_tuner           = airspy_s_tuner,
+
+	.vidioc_g_frequency       = airspy_g_frequency,
+	.vidioc_s_frequency       = airspy_s_frequency,
+	.vidioc_enum_freq_bands   = airspy_enum_freq_bands,
+
+	.vidioc_subscribe_event   = v4l2_ctrl_subscribe_event,
+	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
+	.vidioc_log_status        = v4l2_ctrl_log_status,
+};
+
+static struct video_device g_vdev = {
+	.name                     = "100ask_virtual_video",
+	.release                  = video_device_release_empty,
+	.fops                     = &virtual_fops,
+	.ioctl_ops                = &virtual_ioctl_ops,
+};
+static struct v4l2_device g_v4l2_dev;
+
+static struct vb2_queue g_vb_queue;
+
+static const struct vb2_ops virtul_vb2_ops = {
+	.queue_setup            = airspy_queue_setup,
+	.buf_queue              = airspy_buf_queue,
+	.start_streaming        = airspy_start_streaming,
+	.stop_streaming         = airspy_stop_streaming,
+	.wait_prepare           = vb2_ops_wait_prepare,
+	.wait_finish            = vb2_ops_wait_finish,
+};
+
+
+static int virtual_video_drv_init(void)
+{
+    int ret;
+    
+    /* 分配/设置/注册video_device */
+
+    /* 设置
+     * 1. 函数调用(比如ioctl)
+     * 2. 队列/buffer的管理
+     */
+
+    g_vb_queue.type = V4L2_BUF_TYPE_SDR_CAPTURE;
+    g_vb_queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
+    g_vb_queue.drv_priv = NULL;
+    g_vb_queue.buf_struct_size = sizeof(struct airspy_frame_buf);
+    g_vb_queue.ops = &virtul_vb2_ops;
+    g_vb_queue.mem_ops = &vb2_vmalloc_memops;
+    g_vb_queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	ret = vb2_queue_init(&s->vb_queue);
+	if (ret) {
+		printk("Could not initialize vb2 queue\n");
+		return -1;;
+	}
+
+    g_vdev.queue = &g_vb_queue;     
+    g_vdev.queue->lock = &s->vb_queue_lock;
+
+	/* Register the v4l2_device structure(辅助作用) */
+	g_v4l2_dev.release = airspy_video_release;
+	ret = v4l2_device_register(NULL, &g_v4l2_dev);
+	if (ret) {
+		printk("Failed to register v4l2-device (%d)\n", ret);
+		return -1;
+	}
+	g_vdev.v4l2_dev = &g_v4l2_dev;
+	g_vdev.lock = &s->v4l2_lock;
+
+	ret = video_register_device(&g_vdev, VFL_TYPE_SDR, -1);
+	if (ret) {
+		printk("Failed to register as video device (%d)\n", ret);
+		return -1;
+	}
+    return 0;
+}
+
+static void virtual_video_drv_exit(void)
+{
+    /* 反注册/释放video_device */
+    v4l2_device_unregister(&g_v4l2_dev);
+    video_unregister_device(&g_vdev);
+}
+
+module_init(virtual_video_drv_init);
+module_exit(virtual_video_drv_exit);
+
+MODULE_LICENSE("GPL");
+
+

STM32MP157/source/A7/13_V4L2/06_virtual_driver/02_virtual_driver_hardware/virtual_video_drv.c

@@ -0,0 +1,227 @@
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-event.h>
+#include <media/videobuf2-v4l2.h>
+#include <media/videobuf2-vmalloc.h>
+
+static struct list_head g_queued_bufs;
+
+/* intermediate buffers with raw data from the USB device */
+struct virtual_frame_buf {
+	/* common v4l buffer stuff -- must be first */
+	struct vb2_v4l2_buffer vb;
+	struct list_head list;
+};
+
+static int virtual_querycap(struct file *file, void *fh,
+		struct v4l2_capability *cap)
+{
+	strlcpy(cap->driver, "100ask_virtual_video", sizeof(cap->driver));
+	strlcpy(cap->card, "no-card", sizeof(cap->card));
+	cap->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING | V4L2_CAP_READWRITE ;
+	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
+
+	return 0;
+}
+
+static int virtual_enum_fmt_cap(struct file *file, void *priv,
+        struct v4l2_fmtdesc *f)
+{
+    if (f->index > 0)
+        return -EINVAL;
+
+    strlcpy(f->description, "100ask motion jpeg", sizeof(f->description));
+    f->pixelformat = V4L2_PIX_FMT_MJPEG;
+
+    return 0;
+}
+
+        
+static int virtual_s_fmt_cap(struct file *file, void *priv,
+        struct v4l2_format *f)
+{
+    /* 分辨用户传入的参数是否可用
+     * 如果不可用, 给APP提供最接近的、硬件支持的参数
+     */
+
+    if (f.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+        return -EINVAL;
+    if (f.fmt.pix.pixelformat != V4L2_PIX_FMT_MJPEG)
+        return -EINVAL;
+    
+    f.fmt.pix.width = 800;
+    f.fmt.pix.height = 600;
+
+    return 0;
+}
+
+static int virtual_enum_framesizes(struct file *file, void *fh,
+                     struct v4l2_frmsizeenum *fsize)
+{
+    if (fsize->index > 0)
+        return -EINVAL;
+
+    fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
+    fsize->discrete.width = 800;
+    fsize->discrete.height = 600;
+    return 0;
+}
+
+
+static const struct v4l2_file_operations virtual_fops = {
+	.owner                    = THIS_MODULE,
+	.open                     = v4l2_fh_open,
+	.release                  = vb2_fop_release,
+	.read                     = vb2_fop_read,
+	.poll                     = vb2_fop_poll,
+	.mmap                     = vb2_fop_mmap,
+	.unlocked_ioctl           = video_ioctl2,
+};
+
+static const struct v4l2_ioctl_ops virtual_ioctl_ops = {
+	.vidioc_querycap          = virtual_querycap,
+
+	.vidioc_enum_fmt_vid_cap  = virtual_enum_fmt_cap,
+	.vidioc_s_fmt_vid_cap     = virtual_s_fmt_cap,
+	.vidioc_enum_framesizes   = virtual_enum_framesizes,
+
+	.vidioc_reqbufs           = vb2_ioctl_reqbufs,
+	.vidioc_create_bufs       = vb2_ioctl_create_bufs,
+	.vidioc_prepare_buf       = vb2_ioctl_prepare_buf,
+	.vidioc_querybuf          = vb2_ioctl_querybuf,
+	.vidioc_qbuf              = vb2_ioctl_qbuf,
+	.vidioc_dqbuf             = vb2_ioctl_dqbuf,
+
+	.vidioc_streamon          = vb2_ioctl_streamon,
+	.vidioc_streamoff         = vb2_ioctl_streamoff,
+};
+
+static struct video_device g_vdev = {
+	.name                     = "100ask_virtual_video",
+	.release                  = video_device_release_empty,
+	.fops                     = &virtual_fops,
+	.ioctl_ops                = &virtual_ioctl_ops,
+};
+static struct v4l2_device g_v4l2_dev;
+
+static struct vb2_queue g_vb_queue;
+
+/* Videobuf2 operations */
+static int virtual_queue_setup(struct vb2_queue *vq,
+		unsigned int *nbuffers,
+		unsigned int *nplanes, unsigned int sizes[], struct device *alloc_devs[])
+{
+    /* 假装:至少需要8个buffer, 每个buffer只有1个plane */
+
+	/* Need at least 8 buffers */
+	if (vq->num_buffers + *nbuffers < 8)
+		*nbuffers = 8 - vq->num_buffers;
+	*nplanes = 1;
+	sizes[0] = PAGE_ALIGN(800*600*2);
+
+	return 0;
+}
+
+        
+static void virtual_buf_queue(struct vb2_buffer *vb)
+{
+
+    /* 把这个buffer告诉硬件相关的驱动程序 */
+
+    struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
+    struct virtual_frame_buf *buf =
+            container_of(vbuf, struct virtual_frame_buf, vb);
+    unsigned long flags;
+
+    //spin_lock_irqsave(&s->queued_bufs_lock, flags);
+    list_add_tail(&buf->list, &g_queued_bufs);
+    //spin_unlock_irqrestore(&s->queued_bufs_lock, flags);
+}
+
+static int virtual_start_streaming(struct vb2_queue *vq, unsigned int count)
+{
+    /* 启动硬件传输 */
+    return 0;
+}
+
+static void virtual_stop_streaming(struct vb2_queue *vq)
+{
+    /* 停止硬件传输 */
+}
+
+
+static const struct vb2_ops virtul_vb2_ops = {
+	.queue_setup            = virtual_queue_setup,
+	.buf_queue              = virtual_buf_queue,
+	.start_streaming        = virtual_start_streaming,
+	.stop_streaming         = virtual_stop_streaming,
+	.wait_prepare           = vb2_ops_wait_prepare,
+	.wait_finish            = vb2_ops_wait_finish,
+};
+
+
+static int virtual_video_drv_init(void)
+{
+    int ret;
+    
+    /* 分配/设置/注册video_device */
+
+    /* 设置
+     * 1. 函数调用(比如ioctl)
+     * 2. 队列/buffer的管理
+     */
+
+    g_vb_queue.type = V4L2_BUF_TYPE_SDR_CAPTURE;
+    g_vb_queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
+    g_vb_queue.drv_priv = NULL;
+    g_vb_queue.buf_struct_size = sizeof(struct virtual_frame_buf);  /* 分配vb时, 分配的空间大小为buf_struct_size */
+    g_vb_queue.ops = &virtul_vb2_ops;
+    g_vb_queue.mem_ops = &vb2_vmalloc_memops;
+    g_vb_queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	ret = vb2_queue_init(&s->vb_queue);
+	if (ret) {
+		printk("Could not initialize vb2 queue\n");
+		return -1;;
+	}
+
+    g_vdev.queue = &g_vb_queue;     
+    g_vdev.queue->lock = &s->vb_queue_lock;
+
+	/* Register the v4l2_device structure(辅助作用) */
+	g_v4l2_dev.release = airspy_video_release;
+	ret = v4l2_device_register(NULL, &g_v4l2_dev);
+	if (ret) {
+		printk("Failed to register v4l2-device (%d)\n", ret);
+		return -1;
+	}
+	g_vdev.v4l2_dev = &g_v4l2_dev;
+	g_vdev.lock = &s->v4l2_lock;
+
+	ret = video_register_device(&g_vdev, VFL_TYPE_SDR, -1);
+	if (ret) {
+		printk("Failed to register as video device (%d)\n", ret);
+		return -1;
+	}
+
+	INIT_LIST_HEAD(&g_queued_bufs);
+    
+    return 0;
+}
+
+static void virtual_video_drv_exit(void)
+{
+    /* 反注册/释放video_device */
+    v4l2_device_unregister(&g_v4l2_dev);
+    video_unregister_device(&g_vdev);
+}
+
+module_init(virtual_video_drv_init);
+module_exit(virtual_video_drv_exit);
+
+MODULE_LICENSE("GPL");
+
+