cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

uvc_queue.c (9592B)


      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 *	uvc_queue.c  --  USB Video Class driver - Buffers management
      4 *
      5 *	Copyright (C) 2005-2010
      6 *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
      7 */
      8
      9#include <linux/atomic.h>
     10#include <linux/kernel.h>
     11#include <linux/mm.h>
     12#include <linux/list.h>
     13#include <linux/module.h>
     14#include <linux/usb.h>
     15#include <linux/videodev2.h>
     16#include <linux/vmalloc.h>
     17#include <linux/wait.h>
     18
     19#include <media/v4l2-common.h>
     20#include <media/videobuf2-dma-sg.h>
     21#include <media/videobuf2-vmalloc.h>
     22
     23#include "uvc.h"
     24
     25/* ------------------------------------------------------------------------
     26 * Video buffers queue management.
     27 *
     28 * Video queues is initialized by uvcg_queue_init(). The function performs
     29 * basic initialization of the uvc_video_queue struct and never fails.
     30 *
     31 * Video buffers are managed by videobuf2. The driver uses a mutex to protect
     32 * the videobuf2 queue operations by serializing calls to videobuf2 and a
     33 * spinlock to protect the IRQ queue that holds the buffers to be processed by
     34 * the driver.
     35 */
     36
     37/* -----------------------------------------------------------------------------
     38 * videobuf2 queue operations
     39 */
     40
     41static int uvc_queue_setup(struct vb2_queue *vq,
     42			   unsigned int *nbuffers, unsigned int *nplanes,
     43			   unsigned int sizes[], struct device *alloc_devs[])
     44{
     45	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
     46	struct uvc_video *video = container_of(queue, struct uvc_video, queue);
     47	struct usb_composite_dev *cdev = video->uvc->func.config->cdev;
     48
     49	if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
     50		*nbuffers = UVC_MAX_VIDEO_BUFFERS;
     51
     52	*nplanes = 1;
     53
     54	sizes[0] = video->imagesize;
     55
     56	if (cdev->gadget->speed < USB_SPEED_SUPER)
     57		video->uvc_num_requests = 4;
     58	else
     59		video->uvc_num_requests = 64;
     60
     61	return 0;
     62}
     63
     64static int uvc_buffer_prepare(struct vb2_buffer *vb)
     65{
     66	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
     67	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
     68	struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf);
     69
     70	if (vb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
     71	    vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
     72		uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
     73		return -EINVAL;
     74	}
     75
     76	if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
     77		return -ENODEV;
     78
     79	buf->state = UVC_BUF_STATE_QUEUED;
     80	if (queue->use_sg) {
     81		buf->sgt = vb2_dma_sg_plane_desc(vb, 0);
     82		buf->sg = buf->sgt->sgl;
     83	} else {
     84		buf->mem = vb2_plane_vaddr(vb, 0);
     85	}
     86	buf->length = vb2_plane_size(vb, 0);
     87	if (vb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
     88		buf->bytesused = 0;
     89	else
     90		buf->bytesused = vb2_get_plane_payload(vb, 0);
     91
     92	return 0;
     93}
     94
     95static void uvc_buffer_queue(struct vb2_buffer *vb)
     96{
     97	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
     98	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
     99	struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf);
    100	unsigned long flags;
    101
    102	spin_lock_irqsave(&queue->irqlock, flags);
    103
    104	if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
    105		list_add_tail(&buf->queue, &queue->irqqueue);
    106	} else {
    107		/* If the device is disconnected return the buffer to userspace
    108		 * directly. The next QBUF call will fail with -ENODEV.
    109		 */
    110		buf->state = UVC_BUF_STATE_ERROR;
    111		vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
    112	}
    113
    114	spin_unlock_irqrestore(&queue->irqlock, flags);
    115}
    116
    117static const struct vb2_ops uvc_queue_qops = {
    118	.queue_setup = uvc_queue_setup,
    119	.buf_prepare = uvc_buffer_prepare,
    120	.buf_queue = uvc_buffer_queue,
    121	.wait_prepare = vb2_ops_wait_prepare,
    122	.wait_finish = vb2_ops_wait_finish,
    123};
    124
    125int uvcg_queue_init(struct uvc_video_queue *queue, struct device *dev, enum v4l2_buf_type type,
    126		    struct mutex *lock)
    127{
    128	struct uvc_video *video = container_of(queue, struct uvc_video, queue);
    129	struct usb_composite_dev *cdev = video->uvc->func.config->cdev;
    130	int ret;
    131
    132	queue->queue.type = type;
    133	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
    134	queue->queue.drv_priv = queue;
    135	queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
    136	queue->queue.ops = &uvc_queue_qops;
    137	queue->queue.lock = lock;
    138	if (cdev->gadget->sg_supported) {
    139		queue->queue.mem_ops = &vb2_dma_sg_memops;
    140		queue->use_sg = 1;
    141	} else {
    142		queue->queue.mem_ops = &vb2_vmalloc_memops;
    143	}
    144
    145	queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY
    146				     | V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
    147	queue->queue.dev = dev;
    148
    149	ret = vb2_queue_init(&queue->queue);
    150	if (ret)
    151		return ret;
    152
    153	spin_lock_init(&queue->irqlock);
    154	INIT_LIST_HEAD(&queue->irqqueue);
    155	queue->flags = 0;
    156
    157	return 0;
    158}
    159
    160/*
    161 * Free the video buffers.
    162 */
    163void uvcg_free_buffers(struct uvc_video_queue *queue)
    164{
    165	vb2_queue_release(&queue->queue);
    166}
    167
    168/*
    169 * Allocate the video buffers.
    170 */
    171int uvcg_alloc_buffers(struct uvc_video_queue *queue,
    172			      struct v4l2_requestbuffers *rb)
    173{
    174	int ret;
    175
    176	ret = vb2_reqbufs(&queue->queue, rb);
    177
    178	return ret ? ret : rb->count;
    179}
    180
    181int uvcg_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
    182{
    183	return vb2_querybuf(&queue->queue, buf);
    184}
    185
    186int uvcg_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
    187{
    188	return vb2_qbuf(&queue->queue, NULL, buf);
    189}
    190
    191/*
    192 * Dequeue a video buffer. If nonblocking is false, block until a buffer is
    193 * available.
    194 */
    195int uvcg_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
    196			int nonblocking)
    197{
    198	return vb2_dqbuf(&queue->queue, buf, nonblocking);
    199}
    200
    201/*
    202 * Poll the video queue.
    203 *
    204 * This function implements video queue polling and is intended to be used by
    205 * the device poll handler.
    206 */
    207__poll_t uvcg_queue_poll(struct uvc_video_queue *queue, struct file *file,
    208			     poll_table *wait)
    209{
    210	return vb2_poll(&queue->queue, file, wait);
    211}
    212
    213int uvcg_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
    214{
    215	return vb2_mmap(&queue->queue, vma);
    216}
    217
    218#ifndef CONFIG_MMU
    219/*
    220 * Get unmapped area.
    221 *
    222 * NO-MMU arch need this function to make mmap() work correctly.
    223 */
    224unsigned long uvcg_queue_get_unmapped_area(struct uvc_video_queue *queue,
    225					   unsigned long pgoff)
    226{
    227	return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
    228}
    229#endif
    230
    231/*
    232 * Cancel the video buffers queue.
    233 *
    234 * Cancelling the queue marks all buffers on the irq queue as erroneous,
    235 * wakes them up and removes them from the queue.
    236 *
    237 * If the disconnect parameter is set, further calls to uvc_queue_buffer will
    238 * fail with -ENODEV.
    239 *
    240 * This function acquires the irq spinlock and can be called from interrupt
    241 * context.
    242 */
    243void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect)
    244{
    245	struct uvc_buffer *buf;
    246	unsigned long flags;
    247
    248	spin_lock_irqsave(&queue->irqlock, flags);
    249	while (!list_empty(&queue->irqqueue)) {
    250		buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
    251				       queue);
    252		list_del(&buf->queue);
    253		buf->state = UVC_BUF_STATE_ERROR;
    254		vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_ERROR);
    255	}
    256	queue->buf_used = 0;
    257
    258	/* This must be protected by the irqlock spinlock to avoid race
    259	 * conditions between uvc_queue_buffer and the disconnection event that
    260	 * could result in an interruptible wait in uvc_dequeue_buffer. Do not
    261	 * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
    262	 * state outside the queue code.
    263	 */
    264	if (disconnect)
    265		queue->flags |= UVC_QUEUE_DISCONNECTED;
    266	spin_unlock_irqrestore(&queue->irqlock, flags);
    267}
    268
    269/*
    270 * Enable or disable the video buffers queue.
    271 *
    272 * The queue must be enabled before starting video acquisition and must be
    273 * disabled after stopping it. This ensures that the video buffers queue
    274 * state can be properly initialized before buffers are accessed from the
    275 * interrupt handler.
    276 *
    277 * Enabling the video queue initializes parameters (such as sequence number,
    278 * sync pattern, ...). If the queue is already enabled, return -EBUSY.
    279 *
    280 * Disabling the video queue cancels the queue and removes all buffers from
    281 * the main queue.
    282 *
    283 * This function can't be called from interrupt context. Use
    284 * uvcg_queue_cancel() instead.
    285 */
    286int uvcg_queue_enable(struct uvc_video_queue *queue, int enable)
    287{
    288	unsigned long flags;
    289	int ret = 0;
    290
    291	if (enable) {
    292		ret = vb2_streamon(&queue->queue, queue->queue.type);
    293		if (ret < 0)
    294			return ret;
    295
    296		queue->sequence = 0;
    297		queue->buf_used = 0;
    298	} else {
    299		ret = vb2_streamoff(&queue->queue, queue->queue.type);
    300		if (ret < 0)
    301			return ret;
    302
    303		spin_lock_irqsave(&queue->irqlock, flags);
    304		INIT_LIST_HEAD(&queue->irqqueue);
    305
    306		/*
    307		 * FIXME: We need to clear the DISCONNECTED flag to ensure that
    308		 * applications will be able to queue buffers for the next
    309		 * streaming run. However, clearing it here doesn't guarantee
    310		 * that the device will be reconnected in the meantime.
    311		 */
    312		queue->flags &= ~UVC_QUEUE_DISCONNECTED;
    313		spin_unlock_irqrestore(&queue->irqlock, flags);
    314	}
    315
    316	return ret;
    317}
    318
    319/* called with &queue_irqlock held.. */
    320void uvcg_complete_buffer(struct uvc_video_queue *queue,
    321					  struct uvc_buffer *buf)
    322{
    323	if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
    324	     buf->length != buf->bytesused) {
    325		buf->state = UVC_BUF_STATE_QUEUED;
    326		vb2_set_plane_payload(&buf->buf.vb2_buf, 0, 0);
    327		return;
    328	}
    329
    330	buf->buf.field = V4L2_FIELD_NONE;
    331	buf->buf.sequence = queue->sequence++;
    332	buf->buf.vb2_buf.timestamp = ktime_get_ns();
    333
    334	vb2_set_plane_payload(&buf->buf.vb2_buf, 0, buf->bytesused);
    335	vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_DONE);
    336}
    337
    338struct uvc_buffer *uvcg_queue_head(struct uvc_video_queue *queue)
    339{
    340	struct uvc_buffer *buf = NULL;
    341
    342	if (!list_empty(&queue->irqqueue))
    343		buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
    344				       queue);
    345
    346	return buf;
    347}
    348