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path: root/drivers/usb/gadget/function/uvc_queue.c
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Diffstat (limited to 'drivers/usb/gadget/function/uvc_queue.c')
-rw-r--r--drivers/usb/gadget/function/uvc_queue.c407
1 files changed, 407 insertions, 0 deletions
diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c
new file mode 100644
index 000000000000..1c29bc954db9
--- /dev/null
+++ b/drivers/usb/gadget/function/uvc_queue.c
@@ -0,0 +1,407 @@
+/*
+ * uvc_queue.c -- USB Video Class driver - Buffers management
+ *
+ * Copyright (C) 2005-2010
+ * 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/atomic.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/videodev2.h>
+#include <linux/vmalloc.h>
+#include <linux/wait.h>
+
+#include <media/v4l2-common.h>
+#include <media/videobuf2-vmalloc.h>
+
+#include "uvc.h"
+
+/* ------------------------------------------------------------------------
+ * Video buffers queue management.
+ *
+ * Video queues is initialized by uvc_queue_init(). The function performs
+ * basic initialization of the uvc_video_queue struct and never fails.
+ *
+ * Video buffers are managed by videobuf2. The driver uses a mutex to protect
+ * the videobuf2 queue operations by serializing calls to videobuf2 and a
+ * spinlock to protect the IRQ queue that holds the buffers to be processed by
+ * the driver.
+ */
+
+/* -----------------------------------------------------------------------------
+ * videobuf2 queue operations
+ */
+
+static int uvc_queue_setup(struct vb2_queue *vq, const struct v4l2_format *fmt,
+ unsigned int *nbuffers, unsigned int *nplanes,
+ unsigned int sizes[], void *alloc_ctxs[])
+{
+ struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
+ struct uvc_video *video = container_of(queue, struct uvc_video, queue);
+
+ if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
+ *nbuffers = UVC_MAX_VIDEO_BUFFERS;
+
+ *nplanes = 1;
+
+ sizes[0] = video->imagesize;
+
+ return 0;
+}
+
+static int uvc_buffer_prepare(struct vb2_buffer *vb)
+{
+ struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
+ struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
+
+ if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
+ vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
+ uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
+ return -EINVAL;
+ }
+
+ if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
+ return -ENODEV;
+
+ buf->state = UVC_BUF_STATE_QUEUED;
+ buf->mem = vb2_plane_vaddr(vb, 0);
+ buf->length = vb2_plane_size(vb, 0);
+ if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
+ buf->bytesused = 0;
+ else
+ buf->bytesused = vb2_get_plane_payload(vb, 0);
+
+ return 0;
+}
+
+static void uvc_buffer_queue(struct vb2_buffer *vb)
+{
+ struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
+ struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
+ unsigned long flags;
+
+ spin_lock_irqsave(&queue->irqlock, flags);
+
+ if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
+ list_add_tail(&buf->queue, &queue->irqqueue);
+ } else {
+ /* If the device is disconnected return the buffer to userspace
+ * directly. The next QBUF call will fail with -ENODEV.
+ */
+ buf->state = UVC_BUF_STATE_ERROR;
+ vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
+ }
+
+ spin_unlock_irqrestore(&queue->irqlock, flags);
+}
+
+static void uvc_wait_prepare(struct vb2_queue *vq)
+{
+ struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
+
+ mutex_unlock(&queue->mutex);
+}
+
+static void uvc_wait_finish(struct vb2_queue *vq)
+{
+ struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
+
+ mutex_lock(&queue->mutex);
+}
+
+static struct vb2_ops uvc_queue_qops = {
+ .queue_setup = uvc_queue_setup,
+ .buf_prepare = uvc_buffer_prepare,
+ .buf_queue = uvc_buffer_queue,
+ .wait_prepare = uvc_wait_prepare,
+ .wait_finish = uvc_wait_finish,
+};
+
+static int uvc_queue_init(struct uvc_video_queue *queue,
+ enum v4l2_buf_type type)
+{
+ int ret;
+
+ queue->queue.type = type;
+ queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
+ queue->queue.drv_priv = queue;
+ queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
+ queue->queue.ops = &uvc_queue_qops;
+ queue->queue.mem_ops = &vb2_vmalloc_memops;
+ queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC
+ | V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
+ ret = vb2_queue_init(&queue->queue);
+ if (ret)
+ return ret;
+
+ mutex_init(&queue->mutex);
+ spin_lock_init(&queue->irqlock);
+ INIT_LIST_HEAD(&queue->irqqueue);
+ queue->flags = 0;
+
+ return 0;
+}
+
+/*
+ * Free the video buffers.
+ */
+static void uvc_free_buffers(struct uvc_video_queue *queue)
+{
+ mutex_lock(&queue->mutex);
+ vb2_queue_release(&queue->queue);
+ mutex_unlock(&queue->mutex);
+}
+
+/*
+ * Allocate the video buffers.
+ */
+static int uvc_alloc_buffers(struct uvc_video_queue *queue,
+ struct v4l2_requestbuffers *rb)
+{
+ int ret;
+
+ mutex_lock(&queue->mutex);
+ ret = vb2_reqbufs(&queue->queue, rb);
+ mutex_unlock(&queue->mutex);
+
+ return ret ? ret : rb->count;
+}
+
+static int uvc_query_buffer(struct uvc_video_queue *queue,
+ struct v4l2_buffer *buf)
+{
+ int ret;
+
+ mutex_lock(&queue->mutex);
+ ret = vb2_querybuf(&queue->queue, buf);
+ mutex_unlock(&queue->mutex);
+
+ return ret;
+}
+
+static int uvc_queue_buffer(struct uvc_video_queue *queue,
+ struct v4l2_buffer *buf)
+{
+ unsigned long flags;
+ int ret;
+
+ mutex_lock(&queue->mutex);
+ ret = vb2_qbuf(&queue->queue, buf);
+ if (ret < 0)
+ goto done;
+
+ spin_lock_irqsave(&queue->irqlock, flags);
+ ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
+ queue->flags &= ~UVC_QUEUE_PAUSED;
+ spin_unlock_irqrestore(&queue->irqlock, flags);
+
+done:
+ mutex_unlock(&queue->mutex);
+ return ret;
+}
+
+/*
+ * Dequeue a video buffer. If nonblocking is false, block until a buffer is
+ * available.
+ */
+static int uvc_dequeue_buffer(struct uvc_video_queue *queue,
+ struct v4l2_buffer *buf, int nonblocking)
+{
+ int ret;
+
+ mutex_lock(&queue->mutex);
+ ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
+ mutex_unlock(&queue->mutex);
+
+ return ret;
+}
+
+/*
+ * Poll the video queue.
+ *
+ * This function implements video queue polling and is intended to be used by
+ * the device poll handler.
+ */
+static unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
+ struct file *file, poll_table *wait)
+{
+ unsigned int ret;
+
+ mutex_lock(&queue->mutex);
+ ret = vb2_poll(&queue->queue, file, wait);
+ mutex_unlock(&queue->mutex);
+
+ return ret;
+}
+
+static int uvc_queue_mmap(struct uvc_video_queue *queue,
+ struct vm_area_struct *vma)
+{
+ int ret;
+
+ mutex_lock(&queue->mutex);
+ ret = vb2_mmap(&queue->queue, vma);
+ mutex_unlock(&queue->mutex);
+
+ return ret;
+}
+
+#ifndef CONFIG_MMU
+/*
+ * Get unmapped area.
+ *
+ * NO-MMU arch need this function to make mmap() work correctly.
+ */
+static unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
+ unsigned long pgoff)
+{
+ unsigned long ret;
+
+ mutex_lock(&queue->mutex);
+ ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
+ mutex_unlock(&queue->mutex);
+ return ret;
+}
+#endif
+
+/*
+ * Cancel the video buffers queue.
+ *
+ * Cancelling the queue marks all buffers on the irq queue as erroneous,
+ * wakes them up and removes them from the queue.
+ *
+ * If the disconnect parameter is set, further calls to uvc_queue_buffer will
+ * fail with -ENODEV.
+ *
+ * This function acquires the irq spinlock and can be called from interrupt
+ * context.
+ */
+static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
+{
+ struct uvc_buffer *buf;
+ unsigned long flags;
+
+ spin_lock_irqsave(&queue->irqlock, flags);
+ while (!list_empty(&queue->irqqueue)) {
+ buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
+ queue);
+ list_del(&buf->queue);
+ buf->state = UVC_BUF_STATE_ERROR;
+ vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
+ }
+ /* This must be protected by the irqlock spinlock to avoid race
+ * conditions between uvc_queue_buffer and the disconnection event that
+ * could result in an interruptible wait in uvc_dequeue_buffer. Do not
+ * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
+ * state outside the queue code.
+ */
+ if (disconnect)
+ queue->flags |= UVC_QUEUE_DISCONNECTED;
+ spin_unlock_irqrestore(&queue->irqlock, flags);
+}
+
+/*
+ * Enable or disable the video buffers queue.
+ *
+ * The queue must be enabled before starting video acquisition and must be
+ * disabled after stopping it. This ensures that the video buffers queue
+ * state can be properly initialized before buffers are accessed from the
+ * interrupt handler.
+ *
+ * Enabling the video queue initializes parameters (such as sequence number,
+ * sync pattern, ...). If the queue is already enabled, return -EBUSY.
+ *
+ * Disabling the video queue cancels the queue and removes all buffers from
+ * the main queue.
+ *
+ * This function can't be called from interrupt context. Use
+ * uvc_queue_cancel() instead.
+ */
+static int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
+{
+ unsigned long flags;
+ int ret = 0;
+
+ mutex_lock(&queue->mutex);
+ if (enable) {
+ ret = vb2_streamon(&queue->queue, queue->queue.type);
+ if (ret < 0)
+ goto done;
+
+ queue->sequence = 0;
+ queue->buf_used = 0;
+ } else {
+ ret = vb2_streamoff(&queue->queue, queue->queue.type);
+ if (ret < 0)
+ goto done;
+
+ spin_lock_irqsave(&queue->irqlock, flags);
+ INIT_LIST_HEAD(&queue->irqqueue);
+
+ /*
+ * FIXME: We need to clear the DISCONNECTED flag to ensure that
+ * applications will be able to queue buffers for the next
+ * streaming run. However, clearing it here doesn't guarantee
+ * that the device will be reconnected in the meantime.
+ */
+ queue->flags &= ~UVC_QUEUE_DISCONNECTED;
+ spin_unlock_irqrestore(&queue->irqlock, flags);
+ }
+
+done:
+ mutex_unlock(&queue->mutex);
+ return ret;
+}
+
+/* called with &queue_irqlock held.. */
+static struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
+ struct uvc_buffer *buf)
+{
+ struct uvc_buffer *nextbuf;
+
+ if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
+ buf->length != buf->bytesused) {
+ buf->state = UVC_BUF_STATE_QUEUED;
+ vb2_set_plane_payload(&buf->buf, 0, 0);
+ return buf;
+ }
+
+ list_del(&buf->queue);
+ if (!list_empty(&queue->irqqueue))
+ nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
+ queue);
+ else
+ nextbuf = NULL;
+
+ buf->buf.v4l2_buf.field = V4L2_FIELD_NONE;
+ buf->buf.v4l2_buf.sequence = queue->sequence++;
+ v4l2_get_timestamp(&buf->buf.v4l2_buf.timestamp);
+
+ vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
+ vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
+
+ return nextbuf;
+}
+
+static struct uvc_buffer *uvc_queue_head(struct uvc_video_queue *queue)
+{
+ struct uvc_buffer *buf = NULL;
+
+ if (!list_empty(&queue->irqqueue))
+ buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
+ queue);
+ else
+ queue->flags |= UVC_QUEUE_PAUSED;
+
+ return buf;
+}
+