USB gadget: video class function driver

This USB video class function driver implements a video capture device from the
host's point of view. It creates a V4L2 output device on the gadget's side to
transfer data from a userspace application over USB.

The UVC-specific descriptors are passed by the gadget driver to the UVC
function driver, making them completely configurable without any modification
to the function's driver code.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 374 insertions, 0 deletions

diff --git a/drivers/usb/gadget/uvc_v4l2.c b/drivers/usb/gadget/uvc_v4l2.c
new file mode 100644
index 00000000000..a7989f29837
--- /dev/null
+++ b/drivers/usb/gadget/uvc_v4l2.c
@@ -0,0 +1,374 @@
+/*
+ *	uvc_v4l2.c  --  USB Video Class Gadget driver
+ *
+ *	Copyright (C) 2009-2010
+ *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
+ *
+ *	This program is free software; you can redistribute it and/or modify
+ *	it under the terms of the GNU General Public License as published by
+ *	the Free Software Foundation; either version 2 of the License, or
+ *	(at your option) any later version.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/version.h>
+#include <linux/videodev2.h>
+#include <linux/vmalloc.h>
+#include <linux/wait.h>
+
+#include <media/v4l2-dev.h>
+#include <media/v4l2-event.h>
+#include <media/v4l2-ioctl.h>
+
+#include "uvc.h"
+#include "uvc_queue.h"
+
+/* --------------------------------------------------------------------------
+ * Requests handling
+ */
+
+static int
+uvc_send_response(struct uvc_device *uvc, struct uvc_request_data *data)
+{
+	struct usb_composite_dev *cdev = uvc->func.config->cdev;
+	struct usb_request *req = uvc->control_req;
+
+	if (data->length < 0)
+		return usb_ep_set_halt(cdev->gadget->ep0);
+
+	req->length = min(uvc->event_length, data->length);
+	req->zero = data->length < uvc->event_length;
+	req->dma = DMA_ADDR_INVALID;
+
+	memcpy(req->buf, data->data, data->length);
+
+	return usb_ep_queue(cdev->gadget->ep0, req, GFP_KERNEL);
+}
+
+/* --------------------------------------------------------------------------
+ * V4L2
+ */
+
+struct uvc_format
+{
+	u8 bpp;
+	u32 fcc;
+};
+
+static struct uvc_format uvc_formats[] = {
+	{ 16, V4L2_PIX_FMT_YUYV  },
+	{ 0,  V4L2_PIX_FMT_MJPEG },
+};
+
+static int
+uvc_v4l2_get_format(struct uvc_video *video, struct v4l2_format *fmt)
+{
+	fmt->fmt.pix.pixelformat = video->fcc;
+	fmt->fmt.pix.width = video->width;
+	fmt->fmt.pix.height = video->height;
+	fmt->fmt.pix.field = V4L2_FIELD_NONE;
+	fmt->fmt.pix.bytesperline = video->bpp * video->width / 8;
+	fmt->fmt.pix.sizeimage = video->imagesize;
+	fmt->fmt.pix.colorspace = V4L2_COLORSPACE_SRGB;
+	fmt->fmt.pix.priv = 0;
+
+	return 0;
+}
+
+static int
+uvc_v4l2_set_format(struct uvc_video *video, struct v4l2_format *fmt)
+{
+	struct uvc_format *format;
+	unsigned int imagesize;
+	unsigned int bpl;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(uvc_formats); ++i) {
+		format = &uvc_formats[i];
+		if (format->fcc == fmt->fmt.pix.pixelformat)
+			break;
+	}
+
+	if (format == NULL || format->fcc != fmt->fmt.pix.pixelformat) {
+		printk(KERN_INFO "Unsupported format 0x%08x.\n",
+			fmt->fmt.pix.pixelformat);
+		return -EINVAL;
+	}
+
+	bpl = format->bpp * fmt->fmt.pix.width / 8;
+	imagesize = bpl ? bpl * fmt->fmt.pix.height : fmt->fmt.pix.sizeimage;
+
+	video->fcc = format->fcc;
+	video->bpp = format->bpp;
+	video->width = fmt->fmt.pix.width;
+	video->height = fmt->fmt.pix.height;
+	video->imagesize = imagesize;
+
+	fmt->fmt.pix.field = V4L2_FIELD_NONE;
+	fmt->fmt.pix.bytesperline = bpl;
+	fmt->fmt.pix.sizeimage = imagesize;
+	fmt->fmt.pix.colorspace = V4L2_COLORSPACE_SRGB;
+	fmt->fmt.pix.priv = 0;
+
+	return 0;
+}
+
+static int
+uvc_v4l2_open(struct file *file)
+{
+	struct video_device *vdev = video_devdata(file);
+	struct uvc_device *uvc = video_get_drvdata(vdev);
+	struct uvc_file_handle *handle;
+	int ret;
+
+	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
+	if (handle == NULL)
+		return -ENOMEM;
+
+	ret = v4l2_fh_init(&handle->vfh, vdev);
+	if (ret < 0)
+		goto error;
+
+	ret = v4l2_event_init(&handle->vfh);
+	if (ret < 0)
+		goto error;
+
+	ret = v4l2_event_alloc(&handle->vfh, 8);
+	if (ret < 0)
+		goto error;
+
+	v4l2_fh_add(&handle->vfh);
+
+	handle->device = &uvc->video;
+	file->private_data = &handle->vfh;
+
+	uvc_function_connect(uvc);
+	return 0;
+
+error:
+	v4l2_fh_exit(&handle->vfh);
+	return ret;
+}
+
+static int
+uvc_v4l2_release(struct file *file)
+{
+	struct video_device *vdev = video_devdata(file);
+	struct uvc_device *uvc = video_get_drvdata(vdev);
+	struct uvc_file_handle *handle = to_uvc_file_handle(file->private_data);
+	struct uvc_video *video = handle->device;
+
+	uvc_function_disconnect(uvc);
+
+	uvc_video_enable(video, 0);
+	mutex_lock(&video->queue.mutex);
+	if (uvc_free_buffers(&video->queue) < 0)
+		printk(KERN_ERR "uvc_v4l2_release: Unable to free "
+				"buffers.\n");
+	mutex_unlock(&video->queue.mutex);
+
+	file->private_data = NULL;
+	v4l2_fh_del(&handle->vfh);
+	v4l2_fh_exit(&handle->vfh);
+	kfree(handle);
+	return 0;
+}
+
+static long
+uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
+{
+	struct video_device *vdev = video_devdata(file);
+	struct uvc_device *uvc = video_get_drvdata(vdev);
+	struct uvc_file_handle *handle = to_uvc_file_handle(file->private_data);
+	struct usb_composite_dev *cdev = uvc->func.config->cdev;
+	struct uvc_video *video = &uvc->video;
+	int ret = 0;
+
+	switch (cmd) {
+	/* Query capabilities */
+	case VIDIOC_QUERYCAP:
+	{
+		struct v4l2_capability *cap = arg;
+
+		memset(cap, 0, sizeof *cap);
+		strncpy(cap->driver, "g_uvc", sizeof(cap->driver));
+		strncpy(cap->card, cdev->gadget->name, sizeof(cap->card));
+		strncpy(cap->bus_info, dev_name(&cdev->gadget->dev),
+			sizeof cap->bus_info);
+		cap->version = DRIVER_VERSION_NUMBER;
+		cap->capabilities = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
+		break;
+	}
+
+	/* Get & Set format */
+	case VIDIOC_G_FMT:
+	{
+		struct v4l2_format *fmt = arg;
+
+		if (fmt->type != video->queue.type)
+			return -EINVAL;
+
+		return uvc_v4l2_get_format(video, fmt);
+	}
+
+	case VIDIOC_S_FMT:
+	{
+		struct v4l2_format *fmt = arg;
+
+		if (fmt->type != video->queue.type)
+			return -EINVAL;
+
+		return uvc_v4l2_set_format(video, fmt);
+	}
+
+	/* Buffers & streaming */
+	case VIDIOC_REQBUFS:
+	{
+		struct v4l2_requestbuffers *rb = arg;
+
+		if (rb->type != video->queue.type ||
+		    rb->memory != V4L2_MEMORY_MMAP)
+			return -EINVAL;
+
+		ret = uvc_alloc_buffers(&video->queue, rb->count,
+					video->imagesize);
+		if (ret < 0)
+			return ret;
+
+		rb->count = ret;
+		ret = 0;
+		break;
+	}
+
+	case VIDIOC_QUERYBUF:
+	{
+		struct v4l2_buffer *buf = arg;
+
+		if (buf->type != video->queue.type)
+			return -EINVAL;
+
+		return uvc_query_buffer(&video->queue, buf);
+	}
+
+	case VIDIOC_QBUF:
+		if ((ret = uvc_queue_buffer(&video->queue, arg)) < 0)
+			return ret;
+
+		return uvc_video_pump(video);
+
+	case VIDIOC_DQBUF:
+		return uvc_dequeue_buffer(&video->queue, arg,
+			file->f_flags & O_NONBLOCK);
+
+	case VIDIOC_STREAMON:
+	{
+		int *type = arg;
+
+		if (*type != video->queue.type)
+			return -EINVAL;
+
+		return uvc_video_enable(video, 1);
+	}
+
+	case VIDIOC_STREAMOFF:
+	{
+		int *type = arg;
+
+		if (*type != video->queue.type)
+			return -EINVAL;
+
+		return uvc_video_enable(video, 0);
+	}
+
+	/* Events */
+        case VIDIOC_DQEVENT:
+	{
+		struct v4l2_event *event = arg;
+
+		ret = v4l2_event_dequeue(&handle->vfh, event,
+					 file->f_flags & O_NONBLOCK);
+		if (ret == 0 && event->type == UVC_EVENT_SETUP) {
+			struct uvc_event *uvc_event = (void *)&event->u.data;
+
+			/* Tell the complete callback to generate an event for
+			 * the next request that will be enqueued by
+			 * uvc_event_write.
+			 */
+			uvc->event_setup_out =
+				!(uvc_event->req.bRequestType & USB_DIR_IN);
+			uvc->event_length = uvc_event->req.wLength;
+		}
+
+		return ret;
+	}
+
+	case VIDIOC_SUBSCRIBE_EVENT:
+	{
+		struct v4l2_event_subscription *sub = arg;
+
+		if (sub->type < UVC_EVENT_FIRST || sub->type > UVC_EVENT_LAST)
+			return -EINVAL;
+
+		return v4l2_event_subscribe(&handle->vfh, arg);
+	}
+
+	case VIDIOC_UNSUBSCRIBE_EVENT:
+		return v4l2_event_unsubscribe(&handle->vfh, arg);
+
+	case UVCIOC_SEND_RESPONSE:
+		ret = uvc_send_response(uvc, arg);
+		break;
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+
+	return ret;
+}
+
+static long
+uvc_v4l2_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	return video_usercopy(file, cmd, arg, uvc_v4l2_do_ioctl);
+}
+
+static int
+uvc_v4l2_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct video_device *vdev = video_devdata(file);
+	struct uvc_device *uvc = video_get_drvdata(vdev);
+
+	return uvc_queue_mmap(&uvc->video.queue, vma);
+}
+
+static unsigned int
+uvc_v4l2_poll(struct file *file, poll_table *wait)
+{
+	struct video_device *vdev = video_devdata(file);
+	struct uvc_device *uvc = video_get_drvdata(vdev);
+	struct uvc_file_handle *handle = to_uvc_file_handle(file->private_data);
+	unsigned int mask = 0;
+
+	poll_wait(file, &handle->vfh.events->wait, wait);
+	if (v4l2_event_pending(&handle->vfh))
+		mask |= POLLPRI;
+
+	mask |= uvc_queue_poll(&uvc->video.queue, file, wait);
+
+	return mask;
+}
+
+struct v4l2_file_operations uvc_v4l2_fops = {
+	.owner		= THIS_MODULE,
+	.open		= uvc_v4l2_open,
+	.release	= uvc_v4l2_release,
+	.ioctl		= uvc_v4l2_ioctl,
+	.mmap		= uvc_v4l2_mmap,
+	.poll		= uvc_v4l2_poll,
+};
+