[media] uvcvideo: Add support for NOMMU arch

Add support to uvc driver for NOMMU arch including add function
uvc_queue_get_unmapped_area() and make some changes in uvc_queue_mmap().
So that uvc camera can be used on nommu arch like blackfin.

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 54 insertions, 1 deletions

diff --git a/drivers/media/video/uvc/uvc_queue.c b/drivers/media/video/uvc/uvc_queue.c
index f14581bd707f..109a06384a8f 100644
--- a/drivers/media/video/uvc/uvc_queue.c
+++ b/drivers/media/video/uvc/uvc_queue.c
@@ -424,7 +424,7 @@ int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
                         break;
         }
 
-        if (i == queue->count || size != queue->buf_size) {
+        if (i == queue->count || PAGE_ALIGN(size) != queue->buf_size) {
                 ret = -EINVAL;
                 goto done;
         }
@@ -436,6 +436,7 @@ int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
         vma->vm_flags |= VM_IO;
 
         addr = (unsigned long)queue->mem + buffer->buf.m.offset;
+#ifdef CONFIG_MMU
         while (size > 0) {
                 page = vmalloc_to_page((void *)addr);
                 if ((ret = vm_insert_page(vma, start, page)) < 0)
@@ -445,6 +446,7 @@ int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
                 addr += PAGE_SIZE;
                 size -= PAGE_SIZE;
         }
+#endif
 
         vma->vm_ops = &uvc_vm_ops;
         vma->vm_private_data = buffer;
@@ -488,6 +490,36 @@ done:
         return mask;
 }
 
+#ifndef CONFIG_MMU
+/*
+ * Get unmapped area.
+ *
+ * NO-MMU arch need this function to make mmap() work correctly.
+ */
+unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
+                unsigned long pgoff)
+{
+        struct uvc_buffer *buffer;
+        unsigned int i;
+        unsigned long ret;
+
+        mutex_lock(&queue->mutex);
+        for (i = 0; i < queue->count; ++i) {
+                buffer = &queue->buffer[i];
+                if ((buffer->buf.m.offset >> PAGE_SHIFT) == pgoff)
+                        break;
+        }
+        if (i == queue->count) {
+                ret = -EINVAL;
+                goto done;
+        }
+        ret = (unsigned long)queue->mem + buffer->buf.m.offset;
+done:
+        mutex_unlock(&queue->mutex);
+        return ret;
+}
+#endif
+
 /*
  * Enable or disable the video buffers queue.
  *
diff --git a/drivers/media/video/uvc/uvc_v4l2.c b/drivers/media/video/uvc/uvc_v4l2.c
index 6e8aad44c4bd..543a80395b7f 100644
--- a/drivers/media/video/uvc/uvc_v4l2.c
+++ b/drivers/media/video/uvc/uvc_v4l2.c
@@ -1114,6 +1114,20 @@ static unsigned int uvc_v4l2_poll(struct file *file, poll_table *wait)
         return uvc_queue_poll(&stream->queue, file, wait);
 }
 
+#ifndef CONFIG_MMU
+static unsigned long uvc_v4l2_get_unmapped_area(struct file *file,
+                unsigned long addr, unsigned long len, unsigned long pgoff,
+                unsigned long flags)
+{
+        struct uvc_fh *handle = file->private_data;
+        struct uvc_streaming *stream = handle->stream;
+
+        uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_get_unmapped_area\n");
+
+        return uvc_queue_get_unmapped_area(&stream->queue, pgoff);
+}
+#endif
+
 const struct v4l2_file_operations uvc_fops = {
         .owner          = THIS_MODULE,
         .open           = uvc_v4l2_open,
@@ -1122,5 +1136,8 @@ const struct v4l2_file_operations uvc_fops = {
         .read           = uvc_v4l2_read,
         .mmap           = uvc_v4l2_mmap,
         .poll           = uvc_v4l2_poll,
+#ifndef CONFIG_MMU
+        .get_unmapped_area = uvc_v4l2_get_unmapped_area,
+#endif
 };
 
diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h
index 38dd4e18a2ca..0275613c5f33 100644
--- a/drivers/media/video/uvc/uvcvideo.h
+++ b/drivers/media/video/uvc/uvcvideo.h
@@ -600,6 +600,10 @@ extern int uvc_queue_mmap(struct uvc_video_queue *queue,
                 struct vm_area_struct *vma);
 extern unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
                 struct file *file, poll_table *wait);
+#ifndef CONFIG_MMU
+extern unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
+                unsigned long pgoff);
+#endif
 extern int uvc_queue_allocated(struct uvc_video_queue *queue);
 static inline int uvc_queue_streaming(struct uvc_video_queue *queue)
 {