V4L/DVB (6251): Replace video-buf to a more generic approach

video-buf currently does two different tasks:

- Manages video buffers with a common code that allows
  implementing all the V4L2 different modes of buffering;

- Controls memory allocations

While the first task is generic, the second were written to support PCI DMA
Scatter/Gather needs. The original approach can't even work for those
video capture hardware that don't support scatter/gather.

I did one approach to make it more generic. While the approach worked
fine for vivi driver, it were not generic enough to handle USB needs.

This patch creates two different modules, one containing the generic
video buffer handling (videobuf-core) and another with PCI DMA S/G.
After this patch, it would be simpler to write an USB video-buf and a
non-SG DMA module.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
http://thread.gmane.org/gmane.comp.video.video4linux/34978/focus=34981
Reviewed-by: Ricardo Cerqueira <v4l@cerqueira.org>

1 files changed, 976 insertions, 0 deletions

diff --git a/drivers/media/video/videobuf-core.c b/drivers/media/video/videobuf-core.c
new file mode 100644
index 000000000000..256501384af7
--- /dev/null
+++ b/drivers/media/video/videobuf-core.c
@@ -0,0 +1,976 @@
+/*
+ * 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/slab.h>
+#include <linux/interrupt.h>
+
+#include <media/videobuf-core.h>
+
+#define MAGIC_BUFFER 0x20070728
+#define MAGIC_CHECK(is,should)	if (unlikely((is) != (should))) \
+	{ printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); BUG(); }
+
+static int debug = 0;
+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...)	if (debug >= level) \
+	printk(KERN_DEBUG "vbuf: " fmt , ## arg)
+
+/* --------------------------------------------------------------------- */
+
+#define CALL(q, f, arg...)						\
+	( (q->int_ops->f)? q->int_ops->f(arg) : 0)
+
+void* videobuf_alloc(struct videobuf_queue* q)
+{
+	struct videobuf_buffer *vb;
+
+	BUG_ON (q->msize<sizeof(*vb));
+
+	if (!q->int_ops || !q->int_ops->alloc) {
+		printk(KERN_ERR "No specific ops defined!\n");
+		BUG();
+	}
+
+	vb = q->int_ops->alloc(q->msize);
+
+	if (NULL != vb) {
+		init_waitqueue_head(&vb->done);
+		vb->magic     = MAGIC_BUFFER;
+	}
+
+	return vb;
+}
+
+int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr)
+{
+	int retval = 0;
+	DECLARE_WAITQUEUE(wait, current);
+
+	MAGIC_CHECK(vb->magic,MAGIC_BUFFER);
+	add_wait_queue(&vb->done, &wait);
+	while (vb->state == STATE_ACTIVE || vb->state == STATE_QUEUED) {
+		if (non_blocking) {
+			retval = -EAGAIN;
+			break;
+		}
+		set_current_state(intr  ? TASK_INTERRUPTIBLE
+					: TASK_UNINTERRUPTIBLE);
+		if (vb->state == STATE_ACTIVE || vb->state == STATE_QUEUED)
+			schedule();
+		set_current_state(TASK_RUNNING);
+		if (intr && signal_pending(current)) {
+			dprintk(1,"buffer waiton: -EINTR\n");
+			retval = -EINTR;
+			break;
+		}
+	}
+	remove_wait_queue(&vb->done, &wait);
+	return retval;
+}
+
+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);
+}
+
+/* --------------------------------------------------------------------- */
+
+
+void videobuf_queue_init(struct videobuf_queue* q,
+			 struct videobuf_queue_ops *ops,
+			 void *dev,
+			 spinlock_t *irqlock,
+			 enum v4l2_buf_type type,
+			 enum v4l2_field field,
+			 unsigned int msize,
+			 void *priv)
+{
+	memset(q,0,sizeof(*q));
+	q->irqlock = irqlock;
+	q->dev     = dev;
+	q->type    = type;
+	q->field   = field;
+	q->msize   = msize;
+	q->ops     = ops;
+	q->priv_data = priv;
+
+	/* 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);
+
+	mutex_init(&q->lock);
+	INIT_LIST_HEAD(&q->stream);
+}
+
+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 (CALL(q,is_mmapped,q->bufs[i])) {
+			dprintk(1,"busy: buffer #%d mapped\n",i);
+			return 1;
+		}
+		if (q->bufs[i]->state == STATE_QUEUED) {
+			dprintk(1,"busy: buffer #%d queued\n",i);
+			return 1;
+		}
+		if (q->bufs[i]->state == STATE_ACTIVE) {
+			dprintk(1,"busy: buffer #%d avtive\n",i);
+			return 1;
+		}
+	}
+	return 0;
+}
+
+void videobuf_queue_cancel(struct videobuf_queue *q)
+{
+	unsigned long flags=0;
+	int i;
+
+	/* remove queued buffers from list */
+	if (q->irqlock)
+		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 == STATE_QUEUED) {
+			list_del(&q->bufs[i]->queue);
+			q->bufs[i]->state = STATE_ERROR;
+		}
+	}
+	if (q->irqlock)
+		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);
+}
+
+/* --------------------------------------------------------------------- */
+
+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;
+}
+
+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 (CALL(q,is_mmapped,vb))
+		b->flags |= V4L2_BUF_FLAG_MAPPED;
+
+	switch (vb->state) {
+	case STATE_PREPARED:
+	case STATE_QUEUED:
+	case STATE_ACTIVE:
+		b->flags |= V4L2_BUF_FLAG_QUEUED;
+		break;
+	case STATE_DONE:
+	case STATE_ERROR:
+		b->flags |= V4L2_BUF_FLAG_DONE;
+		break;
+	case STATE_NEEDS_INIT:
+	case STATE_IDLE:
+		/* nothing */
+		break;
+	}
+
+	if (vb->input != UNSET) {
+		b->flags |= V4L2_BUF_FLAG_INPUT;
+		b->input  = vb->input;
+	}
+
+	b->field     = vb->field;
+	b->timestamp = vb->ts;
+	b->bytesused = vb->size;
+	b->sequence  = vb->field_count >> 1;
+}
+
+int videobuf_reqbufs(struct videobuf_queue *q,
+		 struct v4l2_requestbuffers *req)
+{
+	unsigned int size,count;
+	int retval;
+
+	if (req->type != q->type) {
+		dprintk(1,"reqbufs: queue type invalid\n");
+		return -EINVAL;
+	}
+	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;
+	}
+
+	if (q->streaming) {
+		dprintk(1,"reqbufs: streaming already exists\n");
+		return -EBUSY;
+	}
+	if (!list_empty(&q->stream)) {
+		dprintk(1,"reqbufs: stream running\n");
+		return -EBUSY;
+	}
+
+	mutex_lock(&q->lock);
+	count = req->count;
+	if (count > VIDEO_MAX_FRAME)
+		count = VIDEO_MAX_FRAME;
+	size = 0;
+	q->ops->buf_setup(q,&count,&size);
+	size = PAGE_ALIGN(size);
+	dprintk(1,"reqbufs: bufs=%d, size=0x%x [%d pages total]\n",
+		count, size, (count*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 = count;
+
+ done:
+	mutex_unlock(&q->lock);
+	return retval;
+}
+
+int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
+{
+	if (unlikely(b->type != q->type)) {
+		dprintk(1,"querybuf: Wrong type.\n");
+		return -EINVAL;
+	}
+	if (unlikely(b->index < 0 || b->index >= VIDEO_MAX_FRAME)) {
+		dprintk(1,"querybuf: index out of range.\n");
+		return -EINVAL;
+	}
+	if (unlikely(NULL == q->bufs[b->index])) {
+		dprintk(1,"querybuf: buffer is null.\n");
+		return -EINVAL;
+	}
+	videobuf_status(q,b,q->bufs[b->index],q->type);
+	return 0;
+}
+
+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);
+
+	mutex_lock(&q->lock);
+	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 < 0 || 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 != STATE_NEEDS_INIT && buf->state != STATE_IDLE) {
+		dprintk(1,"qbuf: buffer is already queued or active.\n");
+		goto done;
+	}
+
+	if (b->flags & V4L2_BUF_FLAG_INPUT) {
+		if (b->input >= q->inputs) {
+			dprintk(1,"qbuf: wrong input.\n");
+			goto done;
+		}
+		buf->input = b->input;
+	} else {
+		buf->input = UNSET;
+	}
+
+	switch (b->memory) {
+	case V4L2_MEMORY_MMAP:
+		if (0 == buf->baddr) {
+			dprintk(1,"qbuf: mmap requested but buffer addr is zero!\n");
+			goto done;
+		}
+		break;
+	case V4L2_MEMORY_USERPTR:
+		if (b->length < buf->bsize) {
+			dprintk(1,"qbuf: buffer length is not enough\n");
+			goto done;
+		}
+		if (STATE_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) {
+		if (q->irqlock)
+			spin_lock_irqsave(q->irqlock,flags);
+		q->ops->buf_queue(q,buf);
+		if (q->irqlock)
+			spin_unlock_irqrestore(q->irqlock,flags);
+	}
+	dprintk(1,"qbuf: succeded\n");
+	retval = 0;
+
+ done:
+	mutex_unlock(&q->lock);
+	return retval;
+}
+
+int videobuf_dqbuf(struct videobuf_queue *q,
+	       struct v4l2_buffer *b, int nonblocking)
+{
+	struct videobuf_buffer *buf;
+	int retval;
+
+	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+	mutex_lock(&q->lock);
+	retval = -EBUSY;
+	if (q->reading) {
+		dprintk(1,"dqbuf: Reading running...\n");
+		goto done;
+	}
+	retval = -EINVAL;
+	if (b->type != q->type) {
+		dprintk(1,"dqbuf: Wrong type.\n");
+		goto done;
+	}
+	if (list_empty(&q->stream)) {
+		dprintk(1,"dqbuf: stream running\n");
+		goto done;
+	}
+	buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
+	retval = videobuf_waiton(buf, nonblocking, 1);
+	if (retval < 0) {
+		dprintk(1,"dqbuf: waiton returned %d\n",retval);
+		goto done;
+	}
+	switch (buf->state) {
+	case STATE_ERROR:
+		dprintk(1,"dqbuf: state is error\n");
+		retval = -EIO;
+		CALL(q,sync,q, buf);
+		buf->state = STATE_IDLE;
+		break;
+	case STATE_DONE:
+		dprintk(1,"dqbuf: state is done\n");
+		CALL(q,sync,q, buf);
+		buf->state = STATE_IDLE;
+		break;
+	default:
+		dprintk(1,"dqbuf: state invalid\n");
+		retval = -EINVAL;
+		goto done;
+	}
+	list_del(&buf->stream);
+	memset(b,0,sizeof(*b));
+	videobuf_status(q,b,buf,q->type);
+
+ done:
+	mutex_unlock(&q->lock);
+	return retval;
+}
+
+int videobuf_streamon(struct videobuf_queue *q)
+{
+	struct videobuf_buffer *buf;
+	struct list_head *list;
+	unsigned long flags=0;
+	int retval;
+
+	mutex_lock(&q->lock);
+	retval = -EBUSY;
+	if (q->reading)
+		goto done;
+	retval = 0;
+	if (q->streaming)
+		goto done;
+	q->streaming = 1;
+	if (q->irqlock)
+		spin_lock_irqsave(q->irqlock,flags);
+	list_for_each(list,&q->stream) {
+		buf = list_entry(list, struct videobuf_buffer, stream);
+		if (buf->state == STATE_PREPARED)
+			q->ops->buf_queue(q,buf);
+	}
+	if (q->irqlock)
+		spin_unlock_irqrestore(q->irqlock,flags);
+
+ done:
+	mutex_unlock(&q->lock);
+	return retval;
+}
+
+int videobuf_streamoff(struct videobuf_queue *q)
+{
+	int retval = -EINVAL;
+
+	mutex_lock(&q->lock);
+	if (!q->streaming)
+		goto done;
+	videobuf_queue_cancel(q);
+	q->streaming = 0;
+	retval = 0;
+
+ done:
+	mutex_unlock(&q->lock);
+	return retval;
+}
+
+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(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 */
+	if (q->irqlock)
+		spin_lock_irqsave(q->irqlock,flags);
+	q->ops->buf_queue(q,q->read_buf);
+	if (q->irqlock)
+		spin_unlock_irqrestore(q->irqlock,flags);
+	retval = videobuf_waiton(q->read_buf,0,0);
+	if (0 == retval) {
+		CALL(q,sync,q,q->read_buf);
+		if (STATE_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;
+}
+
+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, nbufs;
+	int retval;
+
+	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+	mutex_lock(&q->lock);
+
+	nbufs = 1; size = 0;
+	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(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;
+		}
+		if (q->irqlock)
+			spin_lock_irqsave(q->irqlock,flags);
+
+		q->ops->buf_queue(q,q->read_buf);
+		if (q->irqlock)
+			spin_unlock_irqrestore(q->irqlock,flags);
+		q->read_off = 0;
+	}
+
+	/* wait until capture is done */
+	retval = videobuf_waiton(q->read_buf, nonblocking, 1);
+	if (0 != retval)
+		goto done;
+
+	CALL(q,sync,q,q->read_buf);
+
+	if (STATE_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=CALL(q,copy_to_user,q,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:
+	mutex_unlock(&q->lock);
+	return retval;
+}
+
+int videobuf_read_start(struct videobuf_queue *q)
+{
+	enum v4l2_field field;
+	unsigned long flags=0;
+	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)
+		return 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);
+	}
+	if (q->irqlock)
+		spin_lock_irqsave(q->irqlock,flags);
+	for (i = 0; i < count; i++)
+		q->ops->buf_queue(q,q->bufs[i]);
+	if (q->irqlock)
+		spin_unlock_irqrestore(q->irqlock,flags);
+	q->reading = 1;
+	return 0;
+}
+
+void videobuf_read_stop(struct videobuf_queue *q)
+{
+	int i;
+
+	videobuf_queue_cancel(q);
+	videobuf_mmap_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;
+	q->reading  = 0;
+}
+
+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",__FUNCTION__);
+	mutex_lock(&q->lock);
+	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->read_buf, nonblocking, 1);
+		if (rc < 0) {
+			if (0 == retval)
+				retval = rc;
+			break;
+		}
+
+		if (q->read_buf->state == STATE_DONE) {
+			rc = CALL (q,copy_stream, q, data, 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);
+			if (q->irqlock)
+				spin_lock_irqsave(q->irqlock,flags);
+			q->ops->buf_queue(q,q->read_buf);
+			if (q->irqlock)
+				spin_unlock_irqrestore(q->irqlock,flags);
+			q->read_buf = NULL;
+		}
+		if (retval < 0)
+			break;
+	}
+
+ done:
+	mutex_unlock(&q->lock);
+	return retval;
+}
+
+unsigned int videobuf_poll_stream(struct file *file,
+				  struct videobuf_queue *q,
+				  poll_table *wait)
+{
+	struct videobuf_buffer *buf = NULL;
+	unsigned int rc = 0;
+
+	mutex_lock(&q->lock);
+	if (q->streaming) {
+		if (!list_empty(&q->stream))
+			buf = list_entry(q->stream.next,
+					 struct videobuf_buffer, stream);
+	} else {
+		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 == STATE_DONE ||
+		    buf->state == STATE_ERROR)
+			rc = POLLIN|POLLRDNORM;
+	}
+	mutex_unlock(&q->lock);
+	return rc;
+}
+
+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_mmap_free(q);
+	if (0 != err)
+		return err;
+
+	/* Allocate and initialize buffers */
+	for (i = 0; i < bcount; i++) {
+		q->bufs[i] = videobuf_alloc(q);
+
+		q->bufs[i]->i      = i;
+		q->bufs[i]->input  = UNSET;
+		q->bufs[i]->memory = memory;
+		q->bufs[i]->bsize  = bsize;
+		switch (memory) {
+		case V4L2_MEMORY_MMAP:
+			q->bufs[i]->boff  = bsize * i;
+			break;
+		case V4L2_MEMORY_USERPTR:
+		case V4L2_MEMORY_OVERLAY:
+			/* nothing */
+			break;
+		}
+	}
+
+	dprintk(1,"mmap setup: %d buffers, %d bytes each\n",
+		bcount,bsize);
+
+	return 0;
+}
+
+int videobuf_mmap_free(struct videobuf_queue *q)
+{
+	int i;
+	int rc;
+
+	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+	rc  = CALL(q,mmap_free,q);
+	if (rc<0)
+		return rc;
+
+	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 rc;
+}
+
+int videobuf_mmap_mapper(struct videobuf_queue *q,
+			 struct vm_area_struct *vma)
+{
+	int retval;
+
+	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+	mutex_lock(&q->lock);
+	retval=CALL(q,mmap_mapper,q,vma);
+	mutex_unlock(&q->lock);
+
+	return retval;
+}
+
+#ifdef CONFIG_VIDEO_V4L1_COMPAT
+int videobuf_cgmbuf(struct videobuf_queue *q,
+		    struct video_mbuf *mbuf, int count)
+{
+	struct v4l2_requestbuffers req;
+	int rc,i;
+
+	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
+
+	memset(&req,0,sizeof(req));
+	req.type   = q->type;
+	req.count  = count;
+	req.memory = V4L2_MEMORY_MMAP;
+	rc = videobuf_reqbufs(q,&req);
+	if (rc < 0)
+		return rc;
+
+	mbuf->frames = req.count;
+	mbuf->size   = 0;
+	for (i = 0; i < mbuf->frames; i++) {
+		mbuf->offsets[i]  = q->bufs[i]->boff;
+		mbuf->size       += q->bufs[i]->bsize;
+	}
+
+	return 0;
+}
+#endif
+
+/* --------------------------------------------------------------------- */
+
+EXPORT_SYMBOL_GPL(videobuf_waiton);
+EXPORT_SYMBOL_GPL(videobuf_iolock);
+
+EXPORT_SYMBOL_GPL(videobuf_alloc);
+
+EXPORT_SYMBOL_GPL(videobuf_queue_init);
+EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
+EXPORT_SYMBOL_GPL(videobuf_queue_is_busy);
+
+EXPORT_SYMBOL_GPL(videobuf_next_field);
+EXPORT_SYMBOL_GPL(videobuf_reqbufs);
+EXPORT_SYMBOL_GPL(videobuf_querybuf);
+EXPORT_SYMBOL_GPL(videobuf_qbuf);
+EXPORT_SYMBOL_GPL(videobuf_dqbuf);
+EXPORT_SYMBOL_GPL(videobuf_cgmbuf);
+EXPORT_SYMBOL_GPL(videobuf_streamon);
+EXPORT_SYMBOL_GPL(videobuf_streamoff);
+
+EXPORT_SYMBOL_GPL(videobuf_read_start);
+EXPORT_SYMBOL_GPL(videobuf_read_stop);
+EXPORT_SYMBOL_GPL(videobuf_read_stream);
+EXPORT_SYMBOL_GPL(videobuf_read_one);
+EXPORT_SYMBOL_GPL(videobuf_poll_stream);
+
+EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
+EXPORT_SYMBOL_GPL(videobuf_mmap_free);
+EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);
+
+/*
+ * Local variables:
+ * c-basic-offset: 8
+ * End:
+ */