path: root/drivers/media/usb/uvc/uvc_v4l2.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      uvc_v4l2.c  --  USB Video Class driver - V4L2 API
 *
 *      Copyright (C) 2005-2010
 *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 */

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

#include <media/v4l2-common.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-event.h>
#include <media/v4l2-ioctl.h>

#include "uvcvideo.h"

/* ------------------------------------------------------------------------
 * UVC ioctls
 */
static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
	struct uvc_xu_control_mapping *xmap)
{
	struct uvc_control_mapping *map;
	unsigned int size;
	int ret;

	map = kzalloc(sizeof(*map), GFP_KERNEL);
	if (map == NULL)
		return -ENOMEM;

	map->id = xmap->id;
	memcpy(map->name, xmap->name, sizeof(map->name));
	memcpy(map->entity, xmap->entity, sizeof(map->entity));
	map->selector = xmap->selector;
	map->size = xmap->size;
	map->offset = xmap->offset;
	map->v4l2_type = xmap->v4l2_type;
	map->data_type = xmap->data_type;

	switch (xmap->v4l2_type) {
	case V4L2_CTRL_TYPE_INTEGER:
	case V4L2_CTRL_TYPE_BOOLEAN:
	case V4L2_CTRL_TYPE_BUTTON:
		break;

	case V4L2_CTRL_TYPE_MENU:
		/* Prevent excessive memory consumption, as well as integer
		 * overflows.
		 */
		if (xmap->menu_count == 0 ||
		    xmap->menu_count > UVC_MAX_CONTROL_MENU_ENTRIES) {
			ret = -EINVAL;
			goto free_map;
		}

		size = xmap->menu_count * sizeof(*map->menu_info);
		map->menu_info = memdup_user(xmap->menu_info, size);
		if (IS_ERR(map->menu_info)) {
			ret = PTR_ERR(map->menu_info);
			goto free_map;
		}

		map->menu_count = xmap->menu_count;
		break;

	default:
		uvc_dbg(chain->dev, CONTROL,
			"Unsupported V4L2 control type %u\n", xmap->v4l2_type);
		ret = -ENOTTY;
		goto free_map;
	}

	ret = uvc_ctrl_add_mapping(chain, map);

	kfree(map->menu_info);
free_map:
	kfree(map);

	return ret;
}

/* ------------------------------------------------------------------------
 * V4L2 interface
 */

/*
 * Find the frame interval closest to the requested frame interval for the
 * given frame format and size. This should be done by the device as part of
 * the Video Probe and Commit negotiation, but some hardware don't implement
 * that feature.
 */
static u32 uvc_try_frame_interval(struct uvc_frame *frame, u32 interval)
{
	unsigned int i;

	if (frame->bFrameIntervalType) {
		u32 best = -1, dist;

		for (i = 0; i < frame->bFrameIntervalType; ++i) {
			dist = interval > frame->dwFrameInterval[i]
			     ? interval - frame->dwFrameInterval[i]
			     : frame->dwFrameInterval[i] - interval;

			if (dist > best)
				break;

			best = dist;
		}

		interval = frame->dwFrameInterval[i-1];
	} else {
		const u32 min = frame->dwFrameInterval[0];
		const u32 max = frame->dwFrameInterval[1];
		const u32 step = frame->dwFrameInterval[2];

		interval = min + (interval - min + step/2) / step * step;
		if (interval > max)
			interval = max;
	}

	return interval;
}

static u32 uvc_v4l2_get_bytesperline(const struct uvc_format *format,
	const struct uvc_frame *frame)
{
	switch (format->fcc) {
	case V4L2_PIX_FMT_NV12:
	case V4L2_PIX_FMT_YVU420:
	case V4L2_PIX_FMT_YUV420:
	case V4L2_PIX_FMT_M420:
		return frame->wWidth;

	default:
		return format->bpp * frame->wWidth / 8;
	}
}

static int uvc_v4l2_try_format(struct uvc_streaming *stream,
	struct v4l2_format *fmt, struct uvc_streaming_control *probe,
	struct uvc_format **uvc_format, struct uvc_frame **uvc_frame)
{
	struct uvc_format *format = NULL;
	struct uvc_frame *frame = NULL;
	u16 rw, rh;
	unsigned int d, maxd;
	unsigned int i;
	u32 interval;
	int ret = 0;
	u8 *fcc;

	if (fmt->type != stream->type)
		return -EINVAL;

	fcc = (u8 *)&fmt->fmt.pix.pixelformat;
	uvc_dbg(stream->dev, FORMAT, "Trying format 0x%08x (%c%c%c%c): %ux%u\n",
		fmt->fmt.pix.pixelformat,
		fcc[0], fcc[1], fcc[2], fcc[3],
		fmt->fmt.pix.width, fmt->fmt.pix.height);

	/* Check if the hardware supports the requested format, use the default
	 * format otherwise.
	 */
	for (i = 0; i < stream->nformats; ++i) {
		format = &stream->format[i];
		if (format->fcc == fmt->fmt.pix.pixelformat)
			break;
	}

	if (i == stream->nformats) {
		format = stream->def_format;
		fmt->fmt.pix.pixelformat = format->fcc;
	}

	/* Find the closest image size. The distance between image sizes is
	 * the size in pixels of the non-overlapping regions between the
	 * requested size and the frame-specified size.
	 */
	rw = fmt->fmt.pix.width;
	rh = fmt->fmt.pix.height;
	maxd = (unsigned int)-1;

	for (i = 0; i < format->nframes; ++i) {
		u16 w = format->frame[i].wWidth;
		u16 h = format->frame[i].wHeight;

		d = min(w, rw) * min(h, rh);
		d = w*h + rw*rh - 2*d;
		if (d < maxd) {
			maxd = d;
			frame = &format->frame[i];
		}

		if (maxd == 0)
			break;
	}

	if (frame == NULL) {
		uvc_dbg(stream->dev, FORMAT, "Unsupported size %ux%u\n",
			fmt->fmt.pix.width, fmt->fmt.pix.height);
		return -EINVAL;
	}

	/* Use the default frame interval. */
	interval = frame->dwDefaultFrameInterval;
	uvc_dbg(stream->dev, FORMAT,
		"Using default frame interval %u.%u us (%u.%u fps)\n",
		interval / 10, interval % 10, 10000000 / interval,
		(100000000 / interval) % 10);

	/* Set the format index, frame index and frame interval. */
	memset(probe, 0, sizeof(*probe));
	probe->bmHint = 1;	/* dwFrameInterval */
	probe->bFormatIndex = format->index;
	probe->bFrameIndex = frame->bFrameIndex;
	probe->dwFrameInterval = uvc_try_frame_interval(frame, interval);
	/* Some webcams stall the probe control set request when the
	 * dwMaxVideoFrameSize field is set to zero. The UVC specification
	 * clearly states that the field is read-only from t