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path: root/drivers/media/video/uvc/uvc_queue.c
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Diffstat (limited to 'drivers/media/video/uvc/uvc_queue.c')
-rw-r--r--drivers/media/video/uvc/uvc_queue.c76
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 32c18229863b..f14581bd707f 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

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