path: root/drivers/usb/gadget/function/uvc_video.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *	uvc_video.c  --  USB Video Class Gadget driver
 *
 *	Copyright (C) 2009-2010
 *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/usb/video.h>
#include <linux/unaligned.h>

#include <media/v4l2-dev.h>

#include "uvc.h"
#include "uvc_queue.h"
#include "uvc_video.h"
#include "uvc_trace.h"

/* --------------------------------------------------------------------------
 * Video codecs
 */

static int
uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
		u8 *data, int len)
{
	struct uvc_device *uvc = container_of(video, struct uvc_device, video);
	struct usb_composite_dev *cdev = uvc->func.config->cdev;
	struct timespec64 ts = ns_to_timespec64(buf->buf.vb2_buf.timestamp);
	int pos = 2;

	data[1] = UVC_STREAM_EOH | video->fid;

	if (video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE)
		data[1] |= UVC_STREAM_ERR;

	if (video->queue.buf_used == 0 && ts.tv_sec) {
		/* dwClockFrequency is 48 MHz */
		u32 pts = ((u64)ts.tv_sec * USEC_PER_SEC + ts.tv_nsec / NSEC_PER_USEC) * 48;

		data[1] |= UVC_STREAM_PTS;
		put_unaligned_le32(pts, &data[pos]);
		pos += 4;
	}

	if (cdev->gadget->ops->get_frame) {
		u32 sof, stc;

		sof = usb_gadget_frame_number(cdev->gadget);
		ktime_get_ts64(&ts);
		stc = ((u64)ts.tv_sec * USEC_PER_SEC + ts.tv_nsec / NSEC_PER_USEC) * 48;

		data[1] |= UVC_STREAM_SCR;
		put_unaligned_le32(stc, &data[pos]);
		put_unaligned_le16(sof, &data[pos+4]);
		pos += 6;
	}

	data[0] = pos;

	if (buf->bytesused - video->queue.buf_used <= len - pos)
		data[1] |= UVC_STREAM_EOF;

	return pos;
}

static int
uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf,
		u8 *data, int len)
{
	struct uvc_video_queue *queue = &video->queue;
	unsigned int nbytes;
	void *mem;

	/* Copy video data to the USB buffer. */
	mem = buf->mem + queue->buf_used;
	nbytes = min_t(unsigned int, len, buf->bytesused - queue->buf_used);

	memcpy(data, mem, nbytes);
	queue->buf_used += nbytes;

	return nbytes;
}

static void
uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video,
		struct uvc_buffer *buf)
{
	void *mem = req->buf;
	struct uvc_request *ureq = req->context;
	int len = video->req_size;
	int ret;

	/* Add a header at the beginning of the payload. */
	if (video->payload_size == 0) {
		ret = uvc_video_encode_header(video, buf, mem, len);
		video->payload_size += ret;
		mem += ret;
		len -= ret;
	}

	/* Process video data. */
	len = min_t(int, video->max_payload_size - video->payload_size, len);
	ret = uvc_video_encode_data(video, buf, mem, len);

	video->payload_size += ret;
	len -= ret;

	req->length = video->req_size - len;
	req->zero = video->payload_size == video->max_payload_size;

	if (buf->bytesused == video->queue.buf_used) {
		video->queue.buf_used = 0;
		buf->state = UVC_BUF_STATE_DONE;
		list_del(&buf->queue);
		video->fid ^= UVC_STREAM_FID;
		ureq->last_buf = buf;

		video->payload_size = 0;
	}

	if (video->payload_size == video->max_payload_size ||
	    video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE ||
	    buf->bytesused == video->queue.buf_used)
		video->payload_size = 0;
}

static void
uvc_video_encode_isoc_sg(struct usb_request *req, struct uvc_video *video,
		struct uvc_buffer *buf)
{
	unsigned int pending = buf->bytesused - video->queue.buf_used;
	struct uvc_request *ureq = req->context;
	struct scatterlist *sg, *iter;
	unsigned int len = buf->req_payload_size;
	unsigned int sg_left, part = 0;
	unsigned int i;