// SPDX-License-Identifier: GPL-2.0+
/*
* uvc_video.c -- USB Video Class Gadget driver
*
* Copyright (C) 2009-2010
* Laurent Pinchart ([email protected])
*/
#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"
/* --------------------------------------------------------------------------
* 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((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((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 = video->req_size;
unsigned int sg_left, part = 0;
unsigned int i;
int header_len;
sg = ureq->sgt.sgl;
sg_init_table(sg, ureq->sgt.nents);
/* Init the header. */
header_len = uvc_video_encode_header(video, buf, ureq->header,
video->req_size);
sg_set_buf(sg, ureq->header, header_len);
len -= header_len;
if (pending <= len)
len = pending;
req->length = (len == pending) ?
len + header_len : video->req_size;
/* Init the pending sgs with payload */
sg = sg_next(sg);
for_each_sg(sg, iter, ureq->sgt.nents - 1, i) {
if (!len || !buf->sg || !buf->sg->length)
break;
sg_left = buf->sg->length - buf->offset;
part = min_t(unsigned int, len, sg_left);
sg_set_page(iter, sg_page(buf->sg), part, buf->offset);
if (part == sg_left) {
buf->offset = 0;
buf->sg = sg_next(buf->sg);
} else {
buf->offset += part;
}
len -= part;
}
/* Assign the video data with header. */
req->buf = NULL;
req->sg = ureq->sgt.sgl;
req->num_sgs = i + 1;
req->length -= len;
video->queue.buf_used += req->length - header_len;
if (buf->bytesused == video->queue.buf_used || !buf->sg ||
video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE) {
video->queue.buf_used = 0;
buf->state = UVC_BUF_STATE_DONE;
buf->offset = 0;
list_del(&buf->queue);
video->fid ^= UVC_STREAM_FID;
ureq->last_buf = buf;
}
}
static void
uvc_video_encode_isoc(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 the header. */
ret = uvc_video_encode_header(video, buf, mem, len);
mem += ret;
len -= ret;
/* Process video data. */
ret = uvc_video_encode_data(video, buf, mem, len);
len -= ret;
req->length = video->req_size - len;
if (buf->bytesused == video->queue.buf_used ||
video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE) {
video->queue.buf_used = 0;
buf->state = UVC_BUF_STATE_DONE;
list_del(&buf->queue);
video->fid ^= UVC_STREAM_FID;
ureq->last_buf = buf;
}
}
/* --------------------------------------------------------------------------
* Request handling
*/
/*
* Callers must take care to hold req_lock when this function may be called
* from multiple threads. For example, when frames are streaming to the host.
*/
static void
uvc_video_free_request(struct uvc_request *ureq, struct usb_ep *ep)
{
sg_free_table(&ureq->sgt);
if (ureq->req && ep) {
usb_ep_free_request(ep, ureq->req);
ureq->req = NULL;
}
kfree(ureq->req_buffer);
ureq->req_buffer = NULL;
if (!list_empty(&ureq->list))
list_del_init(&ureq->list);
kfree(ureq);
}
static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
{
int ret;
ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
if (ret < 0) {
uvcg_err(&video->uvc->func, "Failed to queue request (%d).\n",
ret);
/* If the endpoint is disabled the descriptor may be NULL. */
if (video->ep->desc) {
/* Isochronous endpoints can't be halted. */
if (usb_endpoint_xfer_bulk(video->ep->desc))
usb_ep_set_halt(video->ep);
}
}
return ret;
}
/* This function must be called with video->req_lock held. */
static int uvcg_video_usb_req_queue(struct uvc_video *video,
struct usb_request *req, bool queue_to_ep)
{
bool is_bulk = video->max_payload_size;
struct list_head *list = NULL;
if (!video->is_enabled)
return -ENODEV;
if (queue_to_ep) {
struct uvc_request *ureq = req->context;
/*
* With USB3 handling more requests at a higher speed, we can't
* afford to generate an interrupt for every request. Decide to
* interrupt:
*
* - When no more requests are available in the free queue, as
* this may be our last chance to refill the endpoint's
* request queue.
*
* - When this is request is the last request for the video
* buffer, as we want to start sending the next video buffer
* ASAP in case it doesn't get started already in the next
* iteration of this loop.
*
* - Four times over the length of the requests queue (as
* indicated by video->uvc_num_requests), as a trade-off
* between latency and interrupt load.
*/
if (list_empty(&video->req_free) || ureq->last_buf ||
!(video->req_int_count %
DIV_ROUND_UP(video->uvc_num_requests, 4))) {
video->req_int_count = 0;
req->no_interrupt = 0;
} else {
req->no_interrupt = 1;
}
video->req_int_count++;
return uvcg_video_ep_queue(video, req);
}
/*
* If we're not queuing to the ep, for isoc we're queuing
* to the req_ready list, otherwise req_free.
*/
list = is_bulk ? &video->req_free : &video->req_ready;
list_add_tail(&req->list, list);
return 0;
}
/*
* Must only be called from uvcg_video_enable - since after that we only want to
* queue requests to the endpoint from the uvc_video_complete complete handler.
* This function is needed in order to 'kick start' the flow of requests from
* gadget driver to the usb controller.
*/
static void uvc_video_ep_queue_initial_requests(struct uvc_video *video)
{
struct usb_request *req = NULL;
unsigned long flags = 0;
unsigned int count = 0;
int ret = 0;
/*
* We only queue half of the free list since we still want to have
* some free usb_requests in the free list for the video_pump async_wq
* thread to encode uvc buffers into. Otherwise we could get into a
* situation where the free list does not have any usb requests to
* encode into - we always end up queueing 0 length requests to the
* end point.
*/
unsigned int half_list_size = video->uvc_num_requests / 2;
spin_lock_irqsave(&video->req_lock, flags);
/*
* Take these requests off the free list and queue them all to the
* endpoint. Since we queue 0 length requests with the req_lock held,
* there isn't any 'data' race involved here with the complete handler.
*/
while (count < half_list_size) {
req = list_first_entry(&video->req_free, struct usb_request,
list);
list_del(&req->list);
req->length = 0;
ret = uvcg_video_ep_queue(video, req);
if (ret < 0) {
uvcg_queue_cancel(&video->queue, 0);
break;
}
count++;
}
spin_unlock_irqrestore(&video->req_lock, flags);
}
static void
uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
{
struct uvc_request *ureq = req->context;
struct uvc_video *video = ureq->video;
struct uvc_video_queue *queue = &video->queue;
struct uvc_buffer *last_buf;
struct usb_request *to_queue = req;
unsigned long flags;
bool is_bulk = video->max_payload_size;
int ret = 0;
spin_lock_irqsave(&video->req_lock, flags);
if (!video->is_enabled) {
/*
* When is_enabled is false, uvcg_video_disable() ensures
* that in-flight uvc_buffers are returned, so we can
* safely call free_request without worrying about
* last_buf.
*/
uvc_video_free_request(ureq, ep);
spin_unlock_irqrestore(&video->req_lock, flags);
return;
}
last_buf = ureq->last_buf;
ureq->last_buf = NULL;
spin_unlock_irqrestore(&video->req_lock, flags);
switch (req->status) {
case 0:
break;
case -EXDEV:
uvcg_dbg(&video->uvc->func, "VS request missed xfer.\n");
if (req->length != 0)
queue->flags |= UVC_QUEUE_DROP_INCOMPLETE;
break;
case -ESHUTDOWN: /* disconnect from host. */
uvcg_dbg(&video->uvc->func, "VS request cancelled.\n");
uvcg_queue_cancel(queue, 1);
break;
default:
uvcg_warn(&video->uvc->func,
"VS request completed with status %d.\n",
req->status);
uvcg_queue_cancel(queue, 0);
}
if (last_buf) {
spin_lock_irqsave(&queue->irqlock, flags);
uvcg_complete_buffer(queue, last_buf);
spin_unlock_irqrestore(&queue->irqlock, flags);
}
spin_lock_irqsave(&video->req_lock, flags);
/*
* Video stream might have been disabled while we were
* processing the current usb_request. So make sure
* we're still streaming before queueing the usb_request
* back to req_free
*/
if (!video->is_enabled) {
uvc_video_free_request(ureq, ep);
spin_unlock_irqrestore(&video->req_lock, flags);
uvcg_queue_cancel(queue, 0);
return;
}
/*
* Here we check whether any request is available in the ready
* list. If it is, queue it to the ep and add the current
* usb_request to the req_free list - for video_pump to fill in.
* Otherwise, just use the current usb_request to queue a 0
* length request to the ep. Since we always add to the req_free
* list if we dequeue from the ready list, there will never
* be a situation where the req_free list is completely out of
* requests and cannot recover.
*/
to_queue->length = 0;
if (!list_empty(&video->req_ready)) {
to_queue = list_first_entry(&video->req_ready,
struct usb_request, list);
list_del(&to_queue->list);
list_add_tail(&req->list, &video->req_free);
/*
* Queue work to the wq as well since it is possible that a
* buffer may not have been completely encoded with the set of
* in-flight usb requests for whih the complete callbacks are
* firing.
* In that case, if we do not queue work to the worker thread,
* the buffer will never be marked as complete - and therefore
* not be returned to userpsace. As a result,
* dequeue -> queue -> dequeue flow of uvc buffers will not
* happen.
*/
queue_work(video->async_wq, &video->pump);
}
/*
* Queue to the endpoint. The actual queueing to ep will
* only happen on one thread - the async_wq for bulk endpoints
* and this thread for isoc endpoints.
*/
ret = uvcg_video_usb_req_queue(video, to_queue, !is_bulk);
if (ret < 0) {
/*
* Endpoint error, but the stream is still enabled.
* Put request back in req_free for it to be cleaned
* up later.
*/
list_add_tail(&to_queue->list, &video->req_free);
}
spin_unlock_irqrestore(&video->req_lock, flags);
}
static int
uvc_video_free_requests(struct uvc_video *video)
{
struct uvc_request *ureq, *temp;
list_for_each_entry_safe(ureq, temp, &video->ureqs, list)
uvc_video_free_request(ureq, video->ep);
INIT_LIST_HEAD(&video->ureqs);
INIT_LIST_HEAD(&video->req_free);
INIT_LIST_HEAD(&video->req_ready);
video->req_size = 0;
return 0;
}
static int
uvc_video_alloc_requests(struct uvc_video *video)
{
struct uvc_request *ureq;
unsigned int req_size;
unsigned int i;
int ret = -ENOMEM;
BUG_ON(video->req_size);
req_size = video->ep->maxpacket
* max_t(unsigned int, video->ep->maxburst, 1)
* (video->ep->mult);
for (i = 0; i < video->uvc_num_requests; i++) {
ureq = kzalloc(sizeof(struct uvc_request), GFP_KERNEL);
if (ureq == NULL)
goto error;
INIT_LIST_HEAD(&ureq->list);
list_add_tail(&ureq->list, &video->ureqs);
ureq->req_buffer = kmalloc(req_size, GFP_KERNEL);
if (ureq->req_buffer == NULL)
goto error;
ureq->req = usb_ep_alloc_request(video->ep, GFP_KERNEL);
if (ureq->req == NULL)
goto error;
ureq->req->buf = ureq->req_buffer;
ureq->req->length = 0;
ureq->req->complete = uvc_video_complete;
ureq->req->context = ureq;
ureq->video = video;
ureq->last_buf = NULL;
list_add_tail(&ureq->req->list, &video->req_free);
/* req_size/PAGE_SIZE + 1 for overruns and + 1 for header */
sg_alloc_table(&ureq->sgt,
DIV_ROUND_UP(req_size - UVCG_REQUEST_HEADER_LEN,
PAGE_SIZE) + 2, GFP_KERNEL);
}
video->req_size = req_size;
return 0;
error:
uvc_video_free_requests(video);
return ret;
}
/* --------------------------------------------------------------------------
* Video streaming
*/
/*
* uvcg_video_pump - Pump video data into the USB requests
*
* This function fills the available USB requests (listed in req_free) with
* video data from the queued buffers.
*/
static void uvcg_video_pump(struct work_struct *work)
{
struct uvc_video *video = container_of(work, struct uvc_video, pump);
struct uvc_video_queue *queue = &video->queue;
/* video->max_payload_size is only set when using bulk transfer */
bool is_bulk = video->max_payload_size;
struct usb_request *req = NULL;
struct uvc_buffer *buf;
unsigned long flags;
int ret = 0;
while (true) {
if (!video->ep->enabled)
return;
/*
* Check is_enabled and retrieve the first available USB
* request, protected by the request lock.
*/
spin_lock_irqsave(&video->req_lock, flags);
if (!video->is_enabled || list_empty(&video->req_free)) {
spin_unlock_irqrestore(&video->req_lock, flags);
return;
}
req = list_first_entry(&video->req_free, struct usb_request,
list);
list_del(&req->list);
spin_unlock_irqrestore(&video->req_lock, flags);
/*
* Retrieve the first available video buffer and fill the
* request, protected by the video queue irqlock.
*/
spin_lock_irqsave(&queue->irqlock, flags);
buf = uvcg_queue_head(queue);
if (!buf) {
/*
* Either the queue has been disconnected or no video buffer
* available for bulk transfer. Either way, stop processing
* further.
*/
spin_unlock_irqrestore(&queue->irqlock, flags);
break;
}
video->encode(req, video, buf);
spin_unlock_irqrestore(&queue->irqlock, flags);
spin_lock_irqsave(&video->req_lock, flags);
/* For bulk end points we queue from the worker thread
* since we would preferably not want to wait on requests
* to be ready, in the uvcg_video_complete() handler.
* For isoc endpoints we add the request to the ready list
* and only queue it to the endpoint from the complete handler.
*/
ret = uvcg_video_usb_req_queue(video, req, is_bulk);
spin_unlock_irqrestore(&video->req_lock, flags);
if (ret < 0) {
uvcg_queue_cancel(queue, 0);
break;
}
}
spin_lock_irqsave(&video->req_lock, flags);
if (video->is_enabled)
list_add_tail(&req->list, &video->req_free);
else
uvc_video_free_request(req->context, video->ep);
spin_unlock_irqrestore(&video->req_lock, flags);
}
/*
* Disable the video stream
*/
int
uvcg_video_disable(struct uvc_video *video)
{
unsigned long flags;
struct list_head inflight_bufs;
struct usb_request *req, *temp;
struct uvc_buffer *buf, *btemp;
struct uvc_request *ureq, *utemp;
if (video->ep == NULL) {
uvcg_info(&video->uvc->func,
"Video disable failed, device is uninitialized.\n");
return -ENODEV;
}
INIT_LIST_HEAD(&inflight_bufs);
spin_lock_irqsave(&video->req_lock, flags);
video->is_enabled = false;
/*
* Remove any in-flight buffers from the uvc_requests
* because we want to return them before cancelling the
* queue. This ensures that we aren't stuck waiting for
* all complete callbacks to come through before disabling
* vb2 queue.
*/
list_for_each_entry(ureq, &video->ureqs, list) {
if (ureq->last_buf) {
list_add_tail(&ureq->last_buf->queue, &inflight_bufs);
ureq->last_buf = NULL;
}
}
spin_unlock_irqrestore(&video->req_lock, flags);
cancel_work_sync(&video->pump);
uvcg_queue_cancel(&video->queue, 0);
spin_lock_irqsave(&video->req_lock, flags);
/*
* Remove all uvc_requests from ureqs with list_del_init
* This lets uvc_video_free_request correctly identify
* if the uvc_request is attached to a list or not when freeing
* memory.
*/
list_for_each_entry_safe(ureq, utemp, &video->ureqs, list)
list_del_init(&ureq->list);
list_for_each_entry_safe(req, temp, &video->req_free, list) {
list_del(&req->list);
uvc_video_free_request(req->context, video->ep);
}
list_for_each_entry_safe(req, temp, &video->req_ready, list) {
list_del(&req->list);
uvc_video_free_request(req->context, video->ep);
}
INIT_LIST_HEAD(&video->ureqs);
INIT_LIST_HEAD(&video->req_free);
INIT_LIST_HEAD(&video->req_ready);
video->req_size = 0;
spin_unlock_irqrestore(&video->req_lock, flags);
/*
* Return all the video buffers before disabling the queue.
*/
spin_lock_irqsave(&video->queue.irqlock, flags);
list_for_each_entry_safe(buf, btemp, &inflight_bufs, queue) {
list_del(&buf->queue);
uvcg_complete_buffer(&video->queue, buf);
}
spin_unlock_irqrestore(&video->queue.irqlock, flags);
uvcg_queue_enable(&video->queue, 0);
return 0;
}
/*
* Enable the video stream.
*/
int uvcg_video_enable(struct uvc_video *video)
{
int ret;
if (video->ep == NULL) {
uvcg_info(&video->uvc->func,
"Video enable failed, device is uninitialized.\n");
return -ENODEV;
}
/*
* Safe to access request related fields without req_lock because
* this is the only thread currently active, and no other
* request handling thread will become active until this function
* returns.
*/
video->is_enabled = true;
if ((ret = uvcg_queue_enable(&video->queue, 1)) < 0)
return ret;
if ((ret = uvc_video_alloc_requests(video)) < 0)
return ret;
if (video->max_payload_size) {
video->encode = uvc_video_encode_bulk;
video->payload_size = 0;
} else
video->encode = video->queue.use_sg ?
uvc_video_encode_isoc_sg : uvc_video_encode_isoc;
video->req_int_count = 0;
uvc_video_ep_queue_initial_requests(video);
queue_work(video->async_wq, &video->pump);
return ret;
}
/*
* Initialize the UVC video stream.
*/
int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
{
video->is_enabled = false;
INIT_LIST_HEAD(&video->ureqs);
INIT_LIST_HEAD(&video->req_free);
INIT_LIST_HEAD(&video->req_ready);
spin_lock_init(&video->req_lock);
INIT_WORK(&video->pump, uvcg_video_pump);
/* Allocate a work queue for asynchronous video pump handler. */
video->async_wq = alloc_workqueue("uvcgadget", WQ_UNBOUND | WQ_HIGHPRI, 0);
if (!video->async_wq)
return -EINVAL;
video->uvc = uvc;
video->fcc = V4L2_PIX_FMT_YUYV;
video->bpp = 16;
video->width = 320;
video->height = 240;
video->imagesize = 320 * 240 * 2;
/* Initialize the video buffers queue. */
uvcg_queue_init(&video->queue, uvc->v4l2_dev.dev->parent,
V4L2_BUF_TYPE_VIDEO_OUTPUT, &video->mutex);
return 0;
}
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