[media] v4l: move v4l2 core into a separate directory

Currently, the v4l2 core is mixed together with other non-core drivers.
Move them into a separate directory.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 1189 insertions, 0 deletions

diff --git a/drivers/media/v4l2-core/videobuf-core.c b/drivers/media/v4l2-core/videobuf-core.c
new file mode 100644
index 00000000000..bf7a326b1cd
--- /dev/null
+++ b/drivers/media/v4l2-core/videobuf-core.c
@@ -0,0 +1,1189 @@
+/*
+ * generic helper functions for handling video4linux capture buffers
+ *
+ * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
+ *
+ * Highly based on video-buf written originally by:
+ * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
+ * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
+ * (c) 2006 Ted Walther and John Sokol
+ *
+ * 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
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+
+#include <media/videobuf-core.h>
+
+#define MAGIC_BUFFER 0x20070728
+#define MAGIC_CHECK(is, should)						\
+	do {								\
+		if (unlikely((is) != (should))) {			\
+			printk(KERN_ERR					\
+				"magic mismatch: %x (expected %x)\n",	\
+					is, should);			\
+			BUG();						\
+		}							\
+	} while (0)
+
+static int debug;
+module_param(debug, int, 0644);
+
+MODULE_DESCRIPTION("helper module to manage video4linux buffers");
+MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
+MODULE_LICENSE("GPL");
+
+#define dprintk(level, fmt, arg...)					\
+	do {								\
+		if (debug >= level)					\
+			printk(KERN_DEBUG "vbuf: " fmt, ## arg);	\
+	} while (0)
+
+/* --------------------------------------------------------------------- */
+
+#define CALL(q, f, arg...)						\
+	((q->int_ops->f) ? q->int_ops->f(arg) : 0)
+
+struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q)
+{
+	struct videobuf_buffer *vb;
+
+	BUG_ON(q->msize < sizeof(*vb));
+
+	if (!q->int_ops || !q->int_ops->alloc_vb) {
+		printk(KERN_ERR "No specific ops defined!\n");
+		BUG();
+	}
+
+	vb = q->int_ops->alloc_vb(q->msize);
+	if (NULL != vb) {
+		init_waitqueue_head(&vb->done);
+		vb->magic = MAGIC_BUFFER;
+	}
+
+	return vb;
+}
+EXPORT_SYMBOL_GPL(videobuf_alloc_vb);
+
+static int is_state_active_or_queued(struct videobuf_queue *q, struct videobuf_buffer *vb)
+{
+	unsigned long flags;
+	bool rc;
+
+	spin_lock_irqsave(q->irqlock, flags);
+	rc = vb->state != VIDEOBUF_ACTIVE && vb->state != VIDEOBUF_QUEUED;
+	spin_unlock_irqrestore(q->irqlock, flags);
+	return rc;
+};
+
+int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
+		int non_blocking, int intr)
+{
+	bool is_ext_locked;
+	int ret = 0;
+
+	MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
+
+	if (non_blocking) {
+		if (is_state_active_or_queued(q, vb))
+			return 0;
+		return -EAGAIN;
+	}
+
+	is_ext_locked = q->ext_lock && mutex_is_locked(q->ext_lock);
+
+	/* Release vdev lock to prevent this wait from blocking outside access to
+	   the device. */
+	if (is_ext_locked)
+		mutex_unlock(q->ext_lock);
+	if (intr)
+		ret = wait_event_interruptible(vb->done, is_state_active_or_queued(q, vb));
+	else
+		wait_event(vb->done, is_state_active_or_queued(q, vb));
+	/* Relock */
+	if (is_ext_locked)
+		mutex_lock(q->ext_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(videobuf_waiton);
+
+int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
+		    struct v4l2_framebuffer *fbuf)
+{
+	MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	return CALL(q, iolock, q, vb, fbuf);
+}
+EXPORT_SYMBOL_GPL(videobuf_iolock);
+
+void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
+			      struct videobuf_buffer *buf)
+{
+	if (q->int_ops->vaddr)
+		return q->int_ops->vaddr(buf);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(videobuf_queue_to_vaddr);
+
+/* --------------------------------------------------------------------- */
+
+
+void videobuf_queue_core_init(struct videobuf_queue *q,
+			 const struct videobuf_queue_ops *ops,
+			 struct device *dev,
+			 spinlock_t *irqlock,
+			 enum v4l2_buf_type type,
+			 enum v4l2_field field,
+			 unsigned int msize,
+			 void *priv,
+			 struct videobuf_qtype_ops *int_ops,
+			 struct mutex *ext_lock)
+{
+	BUG_ON(!q);
+	memset(q, 0, sizeof(*q));
+	q->irqlock   = irqlock;
+	q->ext_lock  = ext_lock;
+	q->dev       = dev;
+	q->type      = type;
+	q->field     = field;
+	q->msize     = msize;
+	q->ops       = ops;
+	q->priv_data = priv;
+	q->int_ops   = int_ops;
+
+	/* All buffer operations are mandatory */
+	BUG_ON(!q->ops->buf_setup);
+	BUG_ON(!q->ops->buf_prepare);
+	BUG_ON(!q->ops->buf_queue);
+	BUG_ON(!q->ops->buf_release);
+
+	/* Lock is mandatory for queue_cancel to work */
+	BUG_ON(!irqlock);
+
+	/* Having implementations for abstract methods are mandatory */
+	BUG_ON(!q->int_ops);
+
+	mutex_init(&q->vb_lock);
+	init_waitqueue_head(&q->wait);
+	INIT_LIST_HEAD(&q->stream);
+}
+EXPORT_SYMBOL_GPL(videobuf_queue_core_init);
+
+/* Locking: Only usage in bttv unsafe find way to remove */
+int videobuf_queue_is_busy(struct videobuf_queue *q)
+{
+	int i;
+
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	if (q->streaming) {
+		dprintk(1, "busy: streaming active\n");
+		return 1;
+	}
+	if (q->reading) {
+		dprintk(1, "busy: pending read #1\n");
+		return 1;
+	}
+	if (q->read_buf) {
+		dprintk(1, "busy: pending read #2\n");
+		return 1;
+	}
+	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+		if (NULL == q->bufs[i])
+			continue;
+		if (q->bufs[i]->map) {
+			dprintk(1, "busy: buffer #%d mapped\n", i);
+			return 1;
+		}
+		if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
+			dprintk(1, "busy: buffer #%d queued\n", i);
+			return 1;
+		}
+		if (q->bufs[i]->state == VIDEOBUF_ACTIVE) {
+			dprintk(1, "busy: buffer #%d avtive\n", i);
+			return 1;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(videobuf_queue_is_busy);
+
+/**
+ * __videobuf_free() - free all the buffers and their control structures
+ *
+ * This function can only be called if streaming/reading is off, i.e. no buffers
+ * are under control of the driver.
+ */
+/* Locking: Caller holds q->vb_lock */
+static int __videobuf_free(struct videobuf_queue *q)
+{
+	int i;
+
+	dprintk(1, "%s\n", __func__);
+	if (!q)
+		return 0;
+
+	if (q->streaming || q->reading) {
+		dprintk(1, "Cannot free buffers when streaming or reading\n");
+		return -EBUSY;
+	}
+
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	for (i = 0; i < VIDEO_MAX_FRAME; i++)
+		if (q->bufs[i] && q->bufs[i]->map) {
+			dprintk(1, "Cannot free mmapped buffers\n");
+			return -EBUSY;
+		}
+
+	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+		if (NULL == q->bufs[i])
+			continue;
+		q->ops->buf_release(q, q->bufs[i]);
+		kfree(q->bufs[i]);
+		q->bufs[i] = NULL;
+	}
+
+	return 0;
+}
+
+/* Locking: Caller holds q->vb_lock */
+void videobuf_queue_cancel(struct videobuf_queue *q)
+{
+	unsigned long flags = 0;
+	int i;
+
+	q->streaming = 0;
+	q->reading  = 0;
+	wake_up_interruptible_sync(&q->wait);
+
+	/* remove queued buffers from list */
+	spin_lock_irqsave(q->irqlock, flags);
+	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+		if (NULL == q->bufs[i])
+			continue;
+		if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
+			list_del(&q->bufs[i]->queue);
+			q->bufs[i]->state = VIDEOBUF_ERROR;
+			wake_up_all(&q->bufs[i]->done);
+		}
+	}
+	spin_unlock_irqrestore(q->irqlock, flags);
+
+	/* free all buffers + clear queue */
+	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+		if (NULL == q->bufs[i])
+			continue;
+		q->ops->buf_release(q, q->bufs[i]);
+	}
+	INIT_LIST_HEAD(&q->stream);
+}
+EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
+
+/* --------------------------------------------------------------------- */
+
+/* Locking: Caller holds q->vb_lock */
+enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
+{
+	enum v4l2_field field = q->field;
+
+	BUG_ON(V4L2_FIELD_ANY == field);
+
+	if (V4L2_FIELD_ALTERNATE == field) {
+		if (V4L2_FIELD_TOP == q->last) {
+			field   = V4L2_FIELD_BOTTOM;
+			q->last = V4L2_FIELD_BOTTOM;
+		} else {
+			field   = V4L2_FIELD_TOP;
+			q->last = V4L2_FIELD_TOP;
+		}
+	}
+	return field;
+}
+EXPORT_SYMBOL_GPL(videobuf_next_field);
+
+/* Locking: Caller holds q->vb_lock */
+static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
+			    struct videobuf_buffer *vb, enum v4l2_buf_type type)
+{
+	MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	b->index    = vb->i;
+	b->type     = type;
+
+	b->memory   = vb->memory;
+	switch (b->memory) {
+	case V4L2_MEMORY_MMAP:
+		b->m.offset  = vb->boff;
+		b->length    = vb->bsize;
+		break;
+	case V4L2_MEMORY_USERPTR:
+		b->m.userptr = vb->baddr;
+		b->length    = vb->bsize;
+		break;
+	case V4L2_MEMORY_OVERLAY:
+		b->m.offset  = vb->boff;
+		break;
+	}
+
+	b->flags    = 0;
+	if (vb->map)
+		b->flags |= V4L2_BUF_FLAG_MAPPED;
+
+	switch (vb->state) {
+	case VIDEOBUF_PREPARED:
+	case VIDEOBUF_QUEUED:
+	case VIDEOBUF_ACTIVE:
+		b->flags |= V4L2_BUF_FLAG_QUEUED;
+		break;
+	case VIDEOBUF_ERROR:
+		b->flags |= V4L2_BUF_FLAG_ERROR;
+		/* fall through */
+	case VIDEOBUF_DONE:
+		b->flags |= V4L2_BUF_FLAG_DONE;
+		break;
+	case VIDEOBUF_NEEDS_INIT:
+	case VIDEOBUF_IDLE:
+		/* nothing */
+		break;
+	}
+
+	b->field     = vb->field;
+	b->timestamp = vb->ts;
+	b->bytesused = vb->size;
+	b->sequence  = vb->field_count >> 1;
+}
+
+int videobuf_mmap_free(struct videobuf_queue *q)
+{
+	int ret;
+	videobuf_queue_lock(q);
+	ret = __videobuf_free(q);
+	videobuf_queue_unlock(q);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(videobuf_mmap_free);
+
+/* Locking: Caller holds q->vb_lock */
+int __videobuf_mmap_setup(struct videobuf_queue *q,
+			unsigned int bcount, unsigned int bsize,
+			enum v4l2_memory memory)
+{
+	unsigned int i;
+	int err;
+
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	err = __videobuf_free(q);
+	if (0 != err)
+		return err;
+
+	/* Allocate and initialize buffers */
+	for (i = 0; i < bcount; i++) {
+		q->bufs[i] = videobuf_alloc_vb(q);
+
+		if (NULL == q->bufs[i])
+			break;
+
+		q->bufs[i]->i      = i;
+		q->bufs[i]->memory = memory;
+		q->bufs[i]->bsize  = bsize;
+		switch (memory) {
+		case V4L2_MEMORY_MMAP:
+			q->bufs[i]->boff = PAGE_ALIGN(bsize) * i;
+			break;
+		case V4L2_MEMORY_USERPTR:
+		case V4L2_MEMORY_OVERLAY:
+			/* nothing */
+			break;
+		}
+	}
+
+	if (!i)
+		return -ENOMEM;
+
+	dprintk(1, "mmap setup: %d buffers, %d bytes each\n", i, bsize);
+
+	return i;
+}
+EXPORT_SYMBOL_GPL(__videobuf_mmap_setup);
+
+int videobuf_mmap_setup(struct videobuf_queue *q,
+			unsigned int bcount, unsigned int bsize,
+			enum v4l2_memory memory)
+{
+	int ret;
+	videobuf_queue_lock(q);
+	ret = __videobuf_mmap_setup(q, bcount, bsize, memory);
+	videobuf_queue_unlock(q);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
+
+int videobuf_reqbufs(struct videobuf_queue *q,
+		 struct v4l2_requestbuffers *req)
+{
+	unsigned int size, count;
+	int retval;
+
+	if (req->count < 1) {
+		dprintk(1, "reqbufs: count invalid (%d)\n", req->count);
+		return -EINVAL;
+	}
+
+	if (req->memory != V4L2_MEMORY_MMAP     &&
+	    req->memory != V4L2_MEMORY_USERPTR  &&
+	    req->memory != V4L2_MEMORY_OVERLAY) {
+		dprintk(1, "reqbufs: memory type invalid\n");
+		return -EINVAL;
+	}
+
+	videobuf_queue_lock(q);
+	if (req->type != q->type) {
+		dprintk(1, "reqbufs: queue type invalid\n");
+		retval = -EINVAL;
+		goto done;
+	}
+
+	if (q->streaming) {
+		dprintk(1, "reqbufs: streaming already exists\n");
+		retval = -EBUSY;
+		goto done;
+	}
+	if (!list_empty(&q->stream)) {
+		dprintk(1, "reqbufs: stream running\n");
+		retval = -EBUSY;
+		goto done;
+	}
+
+	count = req->count;
+	if (count > VIDEO_MAX_FRAME)
+		count = VIDEO_MAX_FRAME;
+	size = 0;
+	q->ops->buf_setup(q, &count, &size);
+	dprintk(1, "reqbufs: bufs=%d, size=0x%x [%u pages total]\n",
+		count, size,
+		(unsigned int)((count * PAGE_ALIGN(size)) >> PAGE_SHIFT));
+
+	retval = __videobuf_mmap_setup(q, count, size, req->memory);
+	if (retval < 0) {
+		dprintk(1, "reqbufs: mmap setup returned %d\n", retval);
+		goto done;
+	}
+
+	req->count = retval;
+	retval = 0;
+
+ done:
+	videobuf_queue_unlock(q);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(videobuf_reqbufs);
+
+int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
+{
+	int ret = -EINVAL;
+
+	videobuf_queue_lock(q);
+	if (unlikely(b->type != q->type)) {
+		dprintk(1, "querybuf: Wrong type.\n");
+		goto done;
+	}
+	if (unlikely(b->index >= VIDEO_MAX_FRAME)) {
+		dprintk(1, "querybuf: index out of range.\n");
+		goto done;
+	}
+	if (unlikely(NULL == q->bufs[b->index])) {
+		dprintk(1, "querybuf: buffer is null.\n");
+		goto done;
+	}
+
+	videobuf_status(q, b, q->bufs[b->index], q->type);
+
+	ret = 0;
+done:
+	videobuf_queue_unlock(q);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(videobuf_querybuf);
+
+int videobuf_qbuf(struct videobuf_queue *q, struct v4l2_buffer *b)
+{
+	struct videobuf_buffer *buf;
+	enum v4l2_field field;
+	unsigned long flags = 0;
+	int retval;
+
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	if (b->memory == V4L2_MEMORY_MMAP)
+		down_read(&current->mm->mmap_sem);
+
+	videobuf_queue_lock(q);
+	retval = -EBUSY;
+	if (q->reading) {
+		dprintk(1, "qbuf: Reading running...\n");
+		goto done;
+	}
+	retval = -EINVAL;
+	if (b->type != q->type) {
+		dprintk(1, "qbuf: Wrong type.\n");
+		goto done;
+	}
+	if (b->index >= VIDEO_MAX_FRAME) {
+		dprintk(1, "qbuf: index out of range.\n");
+		goto done;
+	}
+	buf = q->bufs[b->index];
+	if (NULL == buf) {
+		dprintk(1, "qbuf: buffer is null.\n");
+		goto done;
+	}
+	MAGIC_CHECK(buf->magic, MAGIC_BUFFER);
+	if (buf->memory != b->memory) {
+		dprintk(1, "qbuf: memory type is wrong.\n");
+		goto done;
+	}
+	if (buf->state != VIDEOBUF_NEEDS_INIT && buf->state != VIDEOBUF_IDLE) {
+		dprintk(1, "qbuf: buffer is already queued or active.\n");
+		goto done;
+	}
+
+	switch (b->memory) {
+	case V4L2_MEMORY_MMAP:
+		if (0 == buf->baddr) {
+			dprintk(1, "qbuf: mmap requested "
+				   "but buffer addr is zero!\n");
+			goto done;
+		}
+		if (q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT
+		    || q->type == V4L2_BUF_TYPE_VBI_OUTPUT
+		    || q->type == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT) {
+			buf->size = b->bytesused;
+			buf->field = b->field;
+			buf->ts = b->timestamp;
+		}
+		break;
+	case V4L2_MEMORY_USERPTR:
+		if (b->length < buf->bsize) {
+			dprintk(1, "qbuf: buffer length is not enough\n");
+			goto done;
+		}
+		if (VIDEOBUF_NEEDS_INIT != buf->state &&
+		    buf->baddr != b->m.userptr)
+			q->ops->buf_release(q, buf);
+		buf->baddr = b->m.userptr;
+		break;
+	case V4L2_MEMORY_OVERLAY:
+		buf->boff = b->m.offset;
+		break;
+	default:
+		dprintk(1, "qbuf: wrong memory type\n");
+		goto done;
+	}
+
+	dprintk(1, "qbuf: requesting next field\n");
+	field = videobuf_next_field(q);
+	retval = q->ops->buf_prepare(q, buf, field);
+	if (0 != retval) {
+		dprintk(1, "qbuf: buffer_prepare returned %d\n", retval);
+		goto done;
+	}
+
+	list_add_tail(&buf->stream, &q->stream);
+	if (q->streaming) {
+		spin_lock_irqsave(q->irqlock, flags);
+		q->ops->buf_queue(q, buf);
+		spin_unlock_irqrestore(q->irqlock, flags);
+	}
+	dprintk(1, "qbuf: succeeded\n");
+	retval = 0;
+	wake_up_interruptible_sync(&q->wait);
+
+done:
+	videobuf_queue_unlock(q);
+
+	if (b->memory == V4L2_MEMORY_MMAP)
+		up_read(&current->mm->mmap_sem);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(videobuf_qbuf);
+
+/* Locking: Caller holds q->vb_lock */
+static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock)
+{
+	int retval;
+
+checks:
+	if (!q->streaming) {
+		dprintk(1, "next_buffer: Not streaming\n");
+		retval = -EINVAL;
+		goto done;
+	}
+
+	if (list_empty(&q->stream)) {
+		if (noblock) {
+			retval = -EAGAIN;
+			dprintk(2, "next_buffer: no buffers to dequeue\n");
+			goto done;
+		} else {
+			dprintk(2, "next_buffer: waiting on buffer\n");
+
+			/* Drop lock to avoid deadlock with qbuf */
+			videobuf_queue_unlock(q);
+
+			/* Checking list_empty and streaming is safe without
+			 * locks because we goto checks to validate while
+			 * holding locks before proceeding */
+			retval = wait_event_interruptible(q->wait,
+				!list_empty(&q->stream) || !q->streaming);
+			videobuf_queue_lock(q);
+
+			if (retval)
+				goto done;
+
+			goto checks;
+		}
+	}
+
+	retval = 0;
+
+done:
+	return retval;
+}
+
+/* Locking: Caller holds q->vb_lock */
+static int stream_next_buffer(struct videobuf_queue *q,
+			struct videobuf_buffer **vb, int nonblocking)
+{
+	int retval;
+	struct videobuf_buffer *buf = NULL;
+
+	retval = stream_next_buffer_check_queue(q, nonblocking);
+	if (retval)
+		goto done;
+
+	buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
+	retval = videobuf_waiton(q, buf, nonblocking, 1);
+	if (retval < 0)
+		goto done;
+
+	*vb = buf;
+done:
+	return retval;
+}
+
+int videobuf_dqbuf(struct videobuf_queue *q,
+		   struct v4l2_buffer *b, int nonblocking)
+{
+	struct videobuf_buffer *buf = NULL;
+	int retval;
+
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	memset(b, 0, sizeof(*b));
+	videobuf_queue_lock(q);
+
+	retval = stream_next_buffer(q, &buf, nonblocking);
+	if (retval < 0) {
+		dprintk(1, "dqbuf: next_buffer error: %i\n", retval);
+		goto done;
+	}
+
+	switch (buf->state) {
+	case VIDEOBUF_ERROR:
+		dprintk(1, "dqbuf: state is error\n");
+		break;
+	case VIDEOBUF_DONE:
+		dprintk(1, "dqbuf: state is done\n");
+		break;
+	default:
+		dprintk(1, "dqbuf: state invalid\n");
+		retval = -EINVAL;
+		goto done;
+	}
+	CALL(q, sync, q, buf);
+	videobuf_status(q, b, buf, q->type);
+	list_del(&buf->stream);
+	buf->state = VIDEOBUF_IDLE;
+	b->flags &= ~V4L2_BUF_FLAG_DONE;
+done:
+	videobuf_queue_unlock(q);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(videobuf_dqbuf);
+
+int videobuf_streamon(struct videobuf_queue *q)
+{
+	struct videobuf_buffer *buf;
+	unsigned long flags = 0;
+	int retval;
+
+	videobuf_queue_lock(q);
+	retval = -EBUSY;
+	if (q->reading)
+		goto done;
+	retval = 0;
+	if (q->streaming)
+		goto done;
+	q->streaming = 1;
+	spin_lock_irqsave(q->irqlock, flags);
+	list_for_each_entry(buf, &q->stream, stream)
+		if (buf->state == VIDEOBUF_PREPARED)
+			q->ops->buf_queue(q, buf);
+	spin_unlock_irqrestore(q->irqlock, flags);
+
+	wake_up_interruptible_sync(&q->wait);
+done:
+	videobuf_queue_unlock(q);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(videobuf_streamon);
+
+/* Locking: Caller holds q->vb_lock */
+static int __videobuf_streamoff(struct videobuf_queue *q)
+{
+	if (!q->streaming)
+		return -EINVAL;
+
+	videobuf_queue_cancel(q);
+
+	return 0;
+}
+
+int videobuf_streamoff(struct videobuf_queue *q)
+{
+	int retval;
+
+	videobuf_queue_lock(q);
+	retval = __videobuf_streamoff(q);
+	videobuf_queue_unlock(q);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(videobuf_streamoff);
+
+/* Locking: Caller holds q->vb_lock */
+static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
+				      char __user *data,
+				      size_t count, loff_t *ppos)
+{
+	enum v4l2_field field;
+	unsigned long flags = 0;
+	int retval;
+
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	/* setup stuff */
+	q->read_buf = videobuf_alloc_vb(q);
+	if (NULL == q->read_buf)
+		return -ENOMEM;
+
+	q->read_buf->memory = V4L2_MEMORY_USERPTR;
+	q->read_buf->baddr  = (unsigned long)data;
+	q->read_buf->bsize  = count;
+
+	field = videobuf_next_field(q);
+	retval = q->ops->buf_prepare(q, q->read_buf, field);
+	if (0 != retval)
+		goto done;
+
+	/* start capture & wait */
+	spin_lock_irqsave(q->irqlock, flags);
+	q->ops->buf_queue(q, q->read_buf);
+	spin_unlock_irqrestore(q->irqlock, flags);
+	retval = videobuf_waiton(q, q->read_buf, 0, 0);
+	if (0 == retval) {
+		CALL(q, sync, q, q->read_buf);
+		if (VIDEOBUF_ERROR == q->read_buf->state)
+			retval = -EIO;
+		else
+			retval = q->read_buf->size;
+	}
+
+done:
+	/* cleanup */
+	q->ops->buf_release(q, q->read_buf);
+	kfree(q->read_buf);
+	q->read_buf = NULL;
+	return retval;
+}
+
+static int __videobuf_copy_to_user(struct videobuf_queue *q,
+				   struct videobuf_buffer *buf,
+				   char __user *data, size_t count,
+				   int nonblocking)
+{
+	void *vaddr = CALL(q, vaddr, buf);
+
+	/* copy to userspace */
+	if (count > buf->size - q->read_off)
+		count = buf->size - q->read_off;
+
+	if (copy_to_user(data, vaddr + q->read_off, count))
+		return -EFAULT;
+
+	return count;
+}
+
+static int __videobuf_copy_stream(struct videobuf_queue *q,
+				  struct videobuf_buffer *buf,
+				  char __user *data, size_t count, size_t pos,
+				  int vbihack, int nonblocking)
+{
+	unsigned int *fc = CALL(q, vaddr, buf);
+
+	if (vbihack) {
+		/* dirty, undocumented hack -- pass the frame counter
+			* within the last four bytes of each vbi data block.
+			* We need that one to maintain backward compatibility
+			* to all vbi decoding software out there ... */
+		fc += (buf->size >> 2) - 1;
+		*fc = buf->field_count >> 1;
+		dprintk(1, "vbihack: %d\n", *fc);
+	}
+
+	/* copy stuff using the common method */
+	count = __videobuf_copy_to_user(q, buf, data, count, nonblocking);
+
+	if ((count == -EFAULT) && (pos == 0))
+		return -EFAULT;
+
+	return count;
+}
+
+ssize_t videobuf_read_one(struct videobuf_queue *q,
+			  char __user *data, size_t count, loff_t *ppos,
+			  int nonblocking)
+{
+	enum v4l2_field field;
+	unsigned long flags = 0;
+	unsigned size = 0, nbufs = 1;
+	int retval;
+
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	videobuf_queue_lock(q);
+
+	q->ops->buf_setup(q, &nbufs, &size);
+
+	if (NULL == q->read_buf  &&
+	    count >= size        &&
+	    !nonblocking) {
+		retval = videobuf_read_zerocopy(q, data, count, ppos);
+		if (retval >= 0  ||  retval == -EIO)
+			/* ok, all done */
+			goto done;
+		/* fallback to kernel bounce buffer on failures */
+	}
+
+	if (NULL == q->read_buf) {
+		/* need to capture a new frame */
+		retval = -ENOMEM;
+		q->read_buf = videobuf_alloc_vb(q);
+
+		dprintk(1, "video alloc=0x%p\n", q->read_buf);
+		if (NULL == q->read_buf)
+			goto done;
+		q->read_buf->memory = V4L2_MEMORY_USERPTR;
+		q->read_buf->bsize = count; /* preferred size */
+		field = videobuf_next_field(q);
+		retval = q->ops->buf_prepare(q, q->read_buf, field);
+
+		if (0 != retval) {
+			kfree(q->read_buf);
+			q->read_buf = NULL;
+			goto done;
+		}
+
+		spin_lock_irqsave(q->irqlock, flags);
+		q->ops->buf_queue(q, q->read_buf);
+		spin_unlock_irqrestore(q->irqlock, flags);
+
+		q->read_off = 0;
+	}
+
+	/* wait until capture is done */
+	retval = videobuf_waiton(q, q->read_buf, nonblocking, 1);
+	if (0 != retval)
+		goto done;
+
+	CALL(q, sync, q, q->read_buf);
+
+	if (VIDEOBUF_ERROR == q->read_buf->state) {
+		/* catch I/O errors */
+		q->ops->buf_release(q, q->read_buf);
+		kfree(q->read_buf);
+		q->read_buf = NULL;
+		retval = -EIO;
+		goto done;
+	}
+
+	/* Copy to userspace */
+	retval = __videobuf_copy_to_user(q, q->read_buf, data, count, nonblocking);
+	if (retval < 0)
+		goto done;
+
+	q->read_off += retval;
+	if (q->read_off == q->read_buf->size) {
+		/* all data copied, cleanup */
+		q->ops->buf_release(q, q->read_buf);
+		kfree(q->read_buf);
+		q->read_buf = NULL;
+	}
+
+done:
+	videobuf_queue_unlock(q);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(videobuf_read_one);
+
+/* Locking: Caller holds q->vb_lock */
+static int __videobuf_read_start(struct videobuf_queue *q)
+{
+	enum v4l2_field field;
+	unsigned long flags = 0;
+	unsigned int count = 0, size = 0;
+	int err, i;
+
+	q->ops->buf_setup(q, &count, &size);
+	if (count < 2)
+		count = 2;
+	if (count > VIDEO_MAX_FRAME)
+		count = VIDEO_MAX_FRAME;
+	size = PAGE_ALIGN(size);
+
+	err = __videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
+	if (err < 0)
+		return err;
+
+	count = err;
+
+	for (i = 0; i < count; i++) {
+		field = videobuf_next_field(q);
+		err = q->ops->buf_prepare(q, q->bufs[i], field);
+		if (err)
+			return err;
+		list_add_tail(&q->bufs[i]->stream, &q->stream);
+	}
+	spin_lock_irqsave(q->irqlock, flags);
+	for (i = 0; i < count; i++)
+		q->ops->buf_queue(q, q->bufs[i]);
+	spin_unlock_irqrestore(q->irqlock, flags);
+	q->reading = 1;
+	return 0;
+}
+
+static void __videobuf_read_stop(struct videobuf_queue *q)
+{
+	int i;
+
+	videobuf_queue_cancel(q);
+	__videobuf_free(q);
+	INIT_LIST_HEAD(&q->stream);
+	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+		if (NULL == q->bufs[i])
+			continue;
+		kfree(q->bufs[i]);
+		q->bufs[i] = NULL;
+	}
+	q->read_buf = NULL;
+}
+
+int videobuf_read_start(struct videobuf_queue *q)
+{
+	int rc;
+
+	videobuf_queue_lock(q);
+	rc = __videobuf_read_start(q);
+	videobuf_queue_unlock(q);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(videobuf_read_start);
+
+void videobuf_read_stop(struct videobuf_queue *q)
+{
+	videobuf_queue_lock(q);
+	__videobuf_read_stop(q);
+	videobuf_queue_unlock(q);
+}
+EXPORT_SYMBOL_GPL(videobuf_read_stop);
+
+void videobuf_stop(struct videobuf_queue *q)
+{
+	videobuf_queue_lock(q);
+
+	if (q->streaming)
+		__videobuf_streamoff(q);
+
+	if (q->reading)
+		__videobuf_read_stop(q);
+
+	videobuf_queue_unlock(q);
+}
+EXPORT_SYMBOL_GPL(videobuf_stop);
+
+ssize_t videobuf_read_stream(struct videobuf_queue *q,
+			     char __user *data, size_t count, loff_t *ppos,
+			     int vbihack, int nonblocking)
+{
+	int rc, retval;
+	unsigned long flags = 0;
+
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	dprintk(2, "%s\n", __func__);
+	videobuf_queue_lock(q);
+	retval = -EBUSY;
+	if (q->streaming)
+		goto done;
+	if (!q->reading) {
+		retval = __videobuf_read_start(q);
+		if (retval < 0)
+			goto done;
+	}
+
+	retval = 0;
+	while (count > 0) {
+		/* get / wait for data */
+		if (NULL == q->read_buf) {
+			q->read_buf = list_entry(q->stream.next,
+						 struct videobuf_buffer,
+						 stream);
+			list_del(&q->read_buf->stream);
+			q->read_off = 0;
+		}
+		rc = videobuf_waiton(q, q->read_buf, nonblocking, 1);
+		if (rc < 0) {
+			if (0 == retval)
+				retval = rc;
+			break;
+		}
+
+		if (q->read_buf->state == VIDEOBUF_DONE) {
+			rc = __videobuf_copy_stream(q, q->read_buf, data + retval, count,
+					retval, vbihack, nonblocking);
+			if (rc < 0) {
+				retval = rc;
+				break;
+			}
+			retval      += rc;
+			count       -= rc;
+			q->read_off += rc;
+		} else {
+			/* some error */
+			q->read_off = q->read_buf->size;
+			if (0 == retval)
+				retval = -EIO;
+		}
+
+		/* requeue buffer when done with copying */
+		if (q->read_off == q->read_buf->size) {
+			list_add_tail(&q->read_buf->stream,
+				      &q->stream);
+			spin_lock_irqsave(q->irqlock, flags);
+			q->ops->buf_queue(q, q->read_buf);
+			spin_unlock_irqrestore(q->irqlock, flags);
+			q->read_buf = NULL;
+		}
+		if (retval < 0)
+			break;
+	}
+
+done:
+	videobuf_queue_unlock(q);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(videobuf_read_stream);
+
+unsigned int videobuf_poll_stream(struct file *file,
+				  struct videobuf_queue *q,
+				  poll_table *wait)
+{
+	unsigned long req_events = poll_requested_events(wait);
+	struct videobuf_buffer *buf = NULL;
+	unsigned int rc = 0;
+
+	videobuf_queue_lock(q);
+	if (q->streaming) {
+		if (!list_empty(&q->stream))
+			buf = list_entry(q->stream.next,
+					 struct videobuf_buffer, stream);
+	} else if (req_events & (POLLIN | POLLRDNORM)) {
+		if (!q->reading)
+			__videobuf_read_start(q);
+		if (!q->reading) {
+			rc = POLLERR;
+		} else if (NULL == q->read_buf) {
+			q->read_buf = list_entry(q->stream.next,
+						 struct videobuf_buffer,
+						 stream);
+			list_del(&q->read_buf->stream);
+			q->read_off = 0;
+		}
+		buf = q->read_buf;
+	}
+	if (!buf)
+		rc = POLLERR;
+
+	if (0 == rc) {
+		poll_wait(file, &buf->done, wait);
+		if (buf->state == VIDEOBUF_DONE ||
+		    buf->state == VIDEOBUF_ERROR) {
+			switch (q->type) {
+			case V4L2_BUF_TYPE_VIDEO_OUTPUT:
+			case V4L2_BUF_TYPE_VBI_OUTPUT:
+			case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
+				rc = POLLOUT | POLLWRNORM;
+				break;
+			default:
+				rc = POLLIN | POLLRDNORM;
+				break;
+			}
+		}
+	}
+	videobuf_queue_unlock(q);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(videobuf_poll_stream);
+
+int videobuf_mmap_mapper(struct videobuf_queue *q, struct vm_area_struct *vma)
+{
+	int rc = -EINVAL;
+	int i;
+
+	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
+
+	if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED)) {
+		dprintk(1, "mmap appl bug: PROT_WRITE and MAP_SHARED are required\n");
+		return -EINVAL;
+	}
+
+	videobuf_queue_lock(q);
+	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+		struct videobuf_buffer *buf = q->bufs[i];
+
+		if (buf && buf->memory == V4L2_MEMORY_MMAP &&
+				buf->boff == (vma->vm_pgoff << PAGE_SHIFT)) {
+			rc = CALL(q, mmap_mapper, q, buf, vma);
+			break;
+		}
+	}
+	videobuf_queue_unlock(q);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);