diff options
Diffstat (limited to 'drivers/media/video/uvc/uvc_queue.c')
-rw-r--r-- | drivers/media/video/uvc/uvc_queue.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/drivers/media/video/uvc/uvc_queue.c b/drivers/media/video/uvc/uvc_queue.c index 32c1822..f14581b 100644 --- a/drivers/media/video/uvc/uvc_queue.c +++ b/drivers/media/video/uvc/uvc_queue.c @@ -380,6 +380,82 @@ done: } /* + * VMA operations. + */ +static void uvc_vm_open(struct vm_area_struct *vma) +{ + struct uvc_buffer *buffer = vma->vm_private_data; + buffer->vma_use_count++; +} + +static void uvc_vm_close(struct vm_area_struct *vma) +{ + struct uvc_buffer *buffer = vma->vm_private_data; + buffer->vma_use_count--; +} + +static const struct vm_operations_struct uvc_vm_ops = { + .open = uvc_vm_open, + .close = uvc_vm_close, +}; + +/* + * Memory-map a video buffer. + * + * This function implements video buffers memory mapping and is intended to be + * used by the device mmap handler. + */ +int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma) +{ + struct uvc_buffer *uninitialized_var(buffer); + struct page *page; + unsigned long addr, start, size; + unsigned int i; + int ret = 0; + + start = vma->vm_start; + size = vma->vm_end - vma->vm_start; + + mutex_lock(&queue->mutex); + + for (i = 0; i < queue->count; ++i) { + buffer = &queue->buffer[i]; + if ((buffer->buf.m.offset >> PAGE_SHIFT) == vma->vm_pgoff) + break; + } + + if (i == queue->count || size != queue->buf_size) { + ret = -EINVAL; + goto done; + } + + /* + * VM_IO marks the area as being an mmaped region for I/O to a + * device. It also prevents the region from being core dumped. + */ + vma->vm_flags |= VM_IO; + + addr = (unsigned long)queue->mem + buffer->buf.m.offset; + while (size > 0) { + page = vmalloc_to_page((void *)addr); + if ((ret = vm_insert_page(vma, start, page)) < 0) + goto done; + + start += PAGE_SIZE; + addr += PAGE_SIZE; + size -= PAGE_SIZE; + } + + vma->vm_ops = &uvc_vm_ops; + vma->vm_private_data = buffer; + uvc_vm_open(vma); + +done: + mutex_unlock(&queue->mutex); + return ret; +} + +/* * Poll the video queue. * * This function implements video queue polling and is intended to be used by |