diff options
Diffstat (limited to 'v4l2.h')
| -rw-r--r-- | v4l2.h | 25 |
1 files changed, 22 insertions, 3 deletions
@@ -147,9 +147,10 @@ int v4l2_set_crop(struct v4l2_device *dev, struct v4l2_rect *rect); * will be stored in the @dev::nbufs field. * * When @memtype is set to V4L2_MEMORY_MMAP the buffers are allocated by the - * driver and mapped to userspace. When @memtype is set to V4L2_MEMORY_USERPTR - * the driver only allocates buffer objects and relies on the application to - * provide memory storage for video frames. + * driver. They can then be mapped to userspace by calling v4l2_mmap_buffers(). + * When @memtype is set to V4L2_MEMORY_USERPTR the driver only allocates buffer + * objects and relies on the application to provide memory storage for video + * frames. * * Return 0 on success or a negative error code on failure. */ @@ -172,6 +173,24 @@ int v4l2_alloc_buffers(struct v4l2_device *dev, enum v4l2_memory memtype, int v4l2_free_buffers(struct v4l2_device *dev); /* + * v4l2_mmap_buffers - Map buffers to application memory space + * @dev: Device instance + * + * Map all the buffers previously allocated by v4l2_alloc_buffers() to the + * application memory space. The buffer memory can be accessed through the mem + * field of each entry in the @dev::buffers array. + * + * Buffers will be automatically unmapped when freed with v4l2_free_buffers(). + * + * This function can only be called when buffers have been allocated with the + * memory type set to V4L2_MEMORY_MMAP. If the memory type is different, or if + * no buffers have been allocated, it will return -EINVAL. + * + * Return 0 on success or a negative error code on failure. + */ +int v4l2_mmap_buffers(struct v4l2_device *dev); + +/* * v4l2_queue_buffer - Queue a buffer for video capture/output * @dev: Device instance * @buffer: Buffer to be queued |