linux/drivers/usb/gadget/uvc_v4l2.c
Hans Verkuil f1e393de38 [media] v4l2-event/ctrls/fh: allocate events per fh and per type instead of just per-fh
The driver had to decide how many events to allocate when the v4l2_fh struct
was created. It was possible to add more events afterwards, but there was no
way to ensure that you wouldn't miss important events if the event queue
would fill up for that filehandle.

In addition, once there were no more free events, any new events were simply
dropped on the floor.

For the control event in particular this made life very difficult since
control status/value changes could just be missed if the number of allocated
events and the speed at which the application read events was too low to keep
up with the number of generated events. The application would have no idea
what the latest state was for a control since it could have missed the latest
control change.

So this patch makes some major changes in how events are allocated. Instead
of allocating events per-filehandle they are now allocated when subscribing an
event. So for that particular event type N events (determined by the driver)
are allocated. Those events are reserved for that particular event type.
This ensures that you will not miss events for a particular type altogether.

In addition, if there are N events in use and a new event is raised, then
the oldest event is dropped and the new one is added. So the latest event
is always available.

This can be further improved by adding the ability to merge the state of
two events together, ensuring that no data is lost at all. This will be
added in the next patch.

This also makes it possible to allow the user to determine the number of
events that will be allocated. This is not implemented at the moment, but
would be trivial.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-07-27 17:53:31 -03:00

358 lines
8.1 KiB
C

/*
* 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 (i == ARRAY_SIZE(uvc_formats)) {
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;
handle = kzalloc(sizeof(*handle), GFP_KERNEL);
if (handle == NULL)
return -ENOMEM;
v4l2_fh_init(&handle->vfh, vdev);
v4l2_fh_add(&handle->vfh);
handle->device = &uvc->video;
file->private_data = &handle->vfh;
uvc_function_connect(uvc);
return 0;
}
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, 2);
}
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.wait, wait);
if (v4l2_event_pending(&handle->vfh))
mask |= POLLPRI;
mask |= uvc_queue_poll(&uvc->video.queue, file, wait);
return mask;
}
static 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,
};