2 files changed, 408 insertions, 0 deletions

diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c
index b856bd105d77..73f3b220b34a 100644
--- a/drivers/media/video/videobuf2-core.c
+++ b/drivers/media/video/videobuf2-core.c
@@ -453,6 +453,11 @@ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
 	unsigned long plane_sizes[VIDEO_MAX_PLANES];
 	int ret = 0;
 
+	if (q->fileio) {
+		dprintk(1, "reqbufs: file io in progress\n");
+		return -EBUSY;
+	}
+
 	if (req->memory != V4L2_MEMORY_MMAP
 			&& req->memory != V4L2_MEMORY_USERPTR) {
 		dprintk(1, "reqbufs: unsupported memory type\n");
@@ -824,6 +829,11 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
 	struct vb2_buffer *vb;
 	int ret = 0;
 
+	if (q->fileio) {
+		dprintk(1, "qbuf: file io in progress\n");
+		return -EBUSY;
+	}
+
 	if (b->type != q->type) {
 		dprintk(1, "qbuf: invalid buffer type\n");
 		return -EINVAL;
@@ -1028,6 +1038,11 @@ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)
 	struct vb2_buffer *vb = NULL;
 	int ret;
 
+	if (q->fileio) {
+		dprintk(1, "dqbuf: file io in progress\n");
+		return -EBUSY;
+	}
+
 	if (b->type != q->type) {
 		dprintk(1, "dqbuf: invalid buffer type\n");
 		return -EINVAL;
@@ -1087,6 +1102,11 @@ int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type)
 {
 	struct vb2_buffer *vb;
 
+	if (q->fileio) {
+		dprintk(1, "streamon: file io in progress\n");
+		return -EBUSY;
+	}
+
 	if (type != q->type) {
 		dprintk(1, "streamon: invalid stream type\n");
 		return -EINVAL;
@@ -1180,6 +1200,11 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
  */
 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)
 {
+	if (q->fileio) {
+		dprintk(1, "streamoff: file io in progress\n");
+		return -EBUSY;
+	}
+
 	if (type != q->type) {
 		dprintk(1, "streamoff: invalid stream type\n");
 		return -EINVAL;
@@ -1303,6 +1328,8 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
 }
 EXPORT_SYMBOL_GPL(vb2_mmap);
 
+static int __vb2_init_fileio(struct vb2_queue *q, int read);
+static int __vb2_cleanup_fileio(struct vb2_queue *q);
 
 /**
  * vb2_poll() - implements poll userspace operation
@@ -1323,9 +1350,30 @@ EXPORT_SYMBOL_GPL(vb2_mmap);
 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
 {
 	unsigned long flags;
+	unsigned int ret;
 	struct vb2_buffer *vb = NULL;
 
 	/*
+	 * Start file io emulator if streaming api has not been used yet.
+	 */
+	if (q->num_buffers == 0 && q->fileio == NULL) {
+		if (!V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_READ)) {
+			ret = __vb2_init_fileio(q, 1);
+			if (ret)
+				return ret;
+		}
+		if (V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_WRITE)) {
+			ret = __vb2_init_fileio(q, 0);
+			if (ret)
+				return ret;
+			/*
+			 * Write to OUTPUT queue can be done immediately.
+			 */
+			return POLLOUT | POLLWRNORM;
+		}
+	}
+
+	/*
 	 * There is nothing to wait for if no buffers have already been queued.
 	 */
 	if (list_empty(&q->queued_list))
@@ -1395,11 +1443,362 @@ EXPORT_SYMBOL_GPL(vb2_queue_init);
  */
 void vb2_queue_release(struct vb2_queue *q)
 {
+	__vb2_cleanup_fileio(q);
 	__vb2_queue_cancel(q);
 	__vb2_queue_free(q);
 }
 EXPORT_SYMBOL_GPL(vb2_queue_release);
 
+/**
+ * struct vb2_fileio_buf - buffer context used by file io emulator
+ *
+ * vb2 provides a compatibility layer and emulator of file io (read and
+ * write) calls on top of streaming API. This structure is used for
+ * tracking context related to the buffers.
+ */
+struct vb2_fileio_buf {
+	void *vaddr;
+	unsigned int size;
+	unsigned int pos;
+	unsigned int queued:1;
+};
+
+/**
+ * struct vb2_fileio_data - queue context used by file io emulator
+ *
+ * vb2 provides a compatibility layer and emulator of file io (read and
+ * write) calls on top of streaming API. For proper operation it required
+ * this structure to save the driver state between each call of the read
+ * or write function.
+ */
+struct vb2_fileio_data {
+	struct v4l2_requestbuffers req;
+	struct v4l2_buffer b;
+	struct vb2_fileio_buf bufs[VIDEO_MAX_FRAME];
+	unsigned int index;
+	unsigned int q_count;
+	unsigned int dq_count;
+	unsigned int flags;
+};
+
+/**
+ * __vb2_init_fileio() - initialize file io emulator
+ * @q:		videobuf2 queue
+ * @read:	mode selector (1 means read, 0 means write)
+ */
+static int __vb2_init_fileio(struct vb2_queue *q, int read)
+{
+	struct vb2_fileio_data *fileio;
+	int i, ret;
+	unsigned int count = 0;
+
+	/*
+	 * Sanity check
+	 */
+	if ((read && !(q->io_modes & VB2_READ)) ||
+	   (!read && !(q->io_modes & VB2_WRITE)))
+		BUG();
+
+	/*
+	 * Check if device supports mapping buffers to kernel virtual space.
+	 */
+	if (!q->mem_ops->vaddr)
+		return -EBUSY;
+
+	/*
+	 * Check if streaming api has not been already activated.
+	 */
+	if (q->streaming || q->num_buffers > 0)
+		return -EBUSY;
+
+	/*
+	 * Start with count 1, driver can increase it in queue_setup()
+	 */
+	count = 1;
+
+	dprintk(3, "setting up file io: mode %s, count %d, flags %08x\n",
+		(read) ? "read" : "write", count, q->io_flags);
+
+	fileio = kzalloc(sizeof(struct vb2_fileio_data), GFP_KERNEL);
+	if (fileio == NULL)
+		return -ENOMEM;
+
+	fileio->flags = q->io_flags;
+
+	/*
+	 * Request buffers and use MMAP type to force driver
+	 * to allocate buffers by itself.
+	 */
+	fileio->req.count = count;
+	fileio->req.memory = V4L2_MEMORY_MMAP;
+	fileio->req.type = q->type;
+	ret = vb2_reqbufs(q, &fileio->req);
+	if (ret)
+		goto err_kfree;
+
+	/*
+	 * Check if plane_count is correct
+	 * (multiplane buffers are not supported).
+	 */
+	if (q->bufs[0]->num_planes != 1) {
+		fileio->req.count = 0;
+		ret = -EBUSY;
+		goto err_reqbufs;
+	}
+
+	/*
+	 * Get kernel address of each buffer.
+	 */
+	for (i = 0; i < q->num_buffers; i++) {
+		fileio->bufs[i].vaddr = vb2_plane_vaddr(q->bufs[i], 0);
+		if (fileio->bufs[i].vaddr == NULL)
+			goto err_reqbufs;
+		fileio->bufs[i].size = vb2_plane_size(q->bufs[i], 0);
+	}
+
+	/*
+	 * Read mode requires pre queuing of all buffers.
+	 */
+	if (read) {
+		/*
+		 * Queue all buffers.
+		 */
+		for (i = 0; i < q->num_buffers; i++) {
+			struct v4l2_buffer *b = &fileio->b;
+			memset(b, 0, sizeof(*b));
+			b->type = q->type;
+			b->memory = q->memory;
+			b->index = i;
+			ret = vb2_qbuf(q, b);
+			if (ret)
+				goto err_reqbufs;
+			fileio->bufs[i].queued = 1;
+		}
+
+		/*
+		 * Start streaming.
+		 */
+		ret = vb2_streamon(q, q->type);
+		if (ret)
+			goto err_reqbufs;
+	}
+
+	q->fileio = fileio;
+
+	return ret;
+
+err_reqbufs:
+	vb2_reqbufs(q, &fileio->req);
+
+err_kfree:
+	kfree(fileio);
+	return ret;
+}
+
+/**
+ * __vb2_cleanup_fileio() - free resourced used by file io emulator
+ * @q:		videobuf2 queue
+ */
+static int __vb2_cleanup_fileio(struct vb2_queue *q)
+{
+	struct vb2_fileio_data *fileio = q->fileio;
+
+	if (fileio) {
+		/*
+		 * Hack fileio context to enable direct calls to vb2 ioctl
+		 * interface.
+		 */
+		q->fileio = NULL;
+
+		vb2_streamoff(q, q->type);
+		fileio->req.count = 0;
+		vb2_reqbufs(q, &fileio->req);
+		kfree(fileio);
+		dprintk(3, "file io emulator closed\n");
+	}
+	return 0;
+}
+
+/**
+ * __vb2_perform_fileio() - perform a single file io (read or write) operation
+ * @q:		videobuf2 queue
+ * @data:	pointed to target userspace buffer
+ * @count:	number of bytes to read or write
+ * @ppos:	file handle position tracking pointer
+ * @nonblock:	mode selector (1 means blocking calls, 0 means nonblocking)
+ * @read:	access mode selector (1 means read, 0 means write)
+ */
+static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_t count,
+		loff_t *ppos, int nonblock, int read)
+{
+	struct vb2_fileio_data *fileio;
+	struct vb2_fileio_buf *buf;
+	int ret, index;
+
+	dprintk(3, "file io: mode %s, offset %ld, count %ld, %sblocking\n",
+		read ? "read" : "write", (long)*ppos, count,
+		nonblock ? "non" : "");
+
+	if (!data)
+		return -EINVAL;
+
+	/*
+	 * Initialize emulator on first call.
+	 */
+	if (!q->fileio) {
+		ret = __vb2_init_fileio(q, read);
+		dprintk(3, "file io: vb2_init_fileio result: %d\n", ret);
+		if (ret)
+			return ret;
+	}
+	fileio = q->fileio;
+
+	/*
+	 * Hack fileio context to enable direct calls to vb2 ioctl interface.
+	 * The pointer will be restored before returning from this function.
+	 */
+	q->fileio = NULL;
+
+	index = fileio->index;
+	buf = &fileio->bufs[index];
+
+	/*
+	 * Check if we need to dequeue the buffer.
+	 */
+	if (buf->queued) {
+		struct vb2_buffer *vb;
+
+		/*
+		 * Call vb2_dqbuf to get buffer back.
+		 */
+		memset(&fileio->b, 0, sizeof(fileio->b));
+		fileio->b.type = q->type;
+		fileio->b.memory = q->memory;
+		fileio->b.index = index;
+		ret = vb2_dqbuf(q, &fileio->b, nonblock);
+		dprintk(5, "file io: vb2_dqbuf result: %d\n", ret);
+		if (ret)
+			goto end;
+		fileio->dq_count += 1;
+
+		/*
+		 * Get number of bytes filled by the driver
+		 */
+		vb = q->bufs[index];
+		buf->size = vb2_get_plane_payload(vb, 0);
+		buf->queued = 0;
+	}
+
+	/*
+	 * Limit count on last few bytes of the buffer.
+	 */
+	if (buf->pos + count > buf->size) {
+		count = buf->size - buf->pos;
+		dprintk(5, "reducing read count: %ld\n", count);
+	}
+
+	/*
+	 * Transfer data to userspace.
+	 */
+	dprintk(3, "file io: copying %ld bytes - buffer %d, offset %u\n",
+		count, index, buf->pos);
+	if (read)
+		ret = copy_to_user(data, buf->vaddr + buf->pos, count);
+	else
+		ret = copy_from_user(buf->vaddr + buf->pos, data, count);
+	if (ret) {
+		dprintk(3, "file io: error copying data\n");
+		ret = -EFAULT;
+		goto end;
+	}
+
+	/*
+	 * Update counters.
+	 */
+	buf->pos += count;
+	*ppos += count;
+
+	/*
+	 * Queue next buffer if required.
+	 */
+	if (buf->pos == buf->size ||
+	   (!read && (fileio->flags & VB2_FILEIO_WRITE_IMMEDIATELY))) {
+		/*
+		 * Check if this is the last buffer to read.
+		 */
+		if (read && (fileio->flags & VB2_FILEIO_READ_ONCE) &&
+		    fileio->dq_count == 1) {
+			dprintk(3, "file io: read limit reached\n");
+			/*
+			 * Restore fileio pointer and release the context.
+			 */
+			q->fileio = fileio;
+			return __vb2_cleanup_fileio(q);
+		}
+
+		/*
+		 * Call vb2_qbuf and give buffer to the driver.
+		 */
+		memset(&fileio->b, 0, sizeof(fileio->b));
+		fileio->b.type = q->type;
+		fileio->b.memory = q->memory;
+		fileio->b.index = index;
+		fileio->b.bytesused = buf->pos;
+		ret = vb2_qbuf(q, &fileio->b);
+		dprintk(5, "file io: vb2_dbuf result: %d\n", ret);
+		if (ret)
+			goto end;
+
+		/*
+		 * Buffer has been queued, update the status
+		 */
+		buf->pos = 0;
+		buf->queued = 1;
+		buf->size = q->bufs[0]->v4l2_planes[0].length;
+		fileio->q_count += 1;
+
+		/*
+		 * Switch to the next buffer
+		 */
+		fileio->index = (index + 1) % q->num_buffers;
+
+		/*
+		 * Start streaming if required.
+		 */
+		if (!read && !q->streaming) {
+			ret = vb2_streamon(q, q->type);
+			if (ret)
+				goto end;
+		}
+	}
+
+	/*
+	 * Return proper number of bytes processed.
+	 */
+	if (ret == 0)
+		ret = count;
+end:
+	/*
+	 * Restore the fileio context and block vb2 ioctl interface.
+	 */
+	q->fileio = fileio;
+	return ret;
+}
+
+size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
+		loff_t *ppos, int nonblocking)
+{
+	return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 1);
+}
+EXPORT_SYMBOL_GPL(vb2_read);
+
+size_t vb2_write(struct vb2_queue *q, char __user *data, size_t count,
+		loff_t *ppos, int nonblocking)
+{
+	return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 0);
+}
+EXPORT_SYMBOL_GPL(vb2_write);
+
 MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2");
 MODULE_AUTHOR("Pawel Osciak, Marek Szyprowski");
 MODULE_LICENSE("GPL");
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 1dafac05ce1a..0d71fc5efc46 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -18,6 +18,7 @@
 #include <linux/videodev2.h>
 
 struct vb2_alloc_ctx;
+struct vb2_fileio_data;
 
 /**
  * struct vb2_mem_ops - memory handling/memory allocator operations
@@ -54,6 +55,7 @@ struct vb2_alloc_ctx;
  *
  * Required ops for USERPTR types: get_userptr, put_userptr.
  * Required ops for MMAP types: alloc, put, num_users, mmap.
+ * Required ops for read/write access types: alloc, put, num_users, vaddr
  */
 struct vb2_mem_ops {
 	void		*(*alloc)(void *alloc_ctx, unsigned long size);
@@ -249,6 +251,7 @@ struct vb2_ops {
  * @done_wq:	waitqueue for processes waiting for buffers ready to be dequeued
  * @alloc_ctx:	memory type/allocator-specific contexts for each plane
  * @streaming:	current streaming state
+ * @fileio:	file io emulator internal data, used only if emulator is active
  */
 struct vb2_queue {
 	enum v4l2_buf_type		type;
@@ -275,6 +278,8 @@ struct vb2_queue {
 	void				*alloc_ctx[VIDEO_MAX_PLANES];
 
 	unsigned int			streaming:1;
+
+	struct vb2_fileio_data		*fileio;
 };
 
 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
@@ -298,6 +303,10 @@ int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
 
 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
+size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
+		loff_t *ppos, int nonblock);
+size_t vb2_write(struct vb2_queue *q, char __user *data, size_t count,
+		loff_t *ppos, int nonblock);
 
 /**
  * vb2_is_streaming() - return streaming status of the queue