The patch makes drmAddBufs/drmMapBufs can handle buffers in video memory

The attached patch adds a new buffer type DRM_FB_BUFFER. It works like AGP
    memory but uses video memory.
From: austinyuan@viatech.com.cn (fd.o bug 1668) Signed-off-by: Dave Airlie
    <airlied@linux.ie>

1 files changed, 175 insertions, 3 deletions

diff --git a/linux/drm_bufs.h b/linux/drm_bufs.h
index 5058a1d3..03900d1b 100644
--- a/linux/drm_bufs.h
+++ b/linux/drm_bufs.h
@@ -993,6 +993,175 @@ int DRM(addbufs_sg)( struct inode *inode, struct file *filp,
 	return 0;
 }
 
+
+int DRM(addbufs_fb)( struct inode *inode, struct file *filp,
+		      unsigned int cmd, unsigned long arg )
+{
+	drm_file_t *priv = filp->private_data;
+	drm_device_t *dev = priv->dev;
+	drm_device_dma_t *dma = dev->dma;
+	drm_buf_desc_t request;
+	drm_buf_entry_t *entry;
+	drm_buf_t *buf;
+	unsigned long offset;
+	unsigned long agp_offset;
+	int count;
+	int order;
+	int size;
+	int alignment;
+	int page_order;
+	int total;
+	int byte_count;
+	int i;
+	drm_buf_t **temp_buflist;
+	drm_buf_desc_t __user *argp = (void __user *)arg;
+
+	if (!drm_core_check_feature(dev, DRIVER_FB_DMA)) return -EINVAL;
+    
+	if ( !dma ) return -EINVAL;
+
+	if ( copy_from_user( &request, argp,
+			     sizeof(request) ) )
+		return -EFAULT;
+
+	count = request.count;
+	order = DRM(order)( request.size );
+	size = 1 << order;
+
+	alignment  = (request.flags & _DRM_PAGE_ALIGN)
+		? PAGE_ALIGN(size) : size;
+	page_order = order - PAGE_SHIFT > 0 ? order - PAGE_SHIFT : 0;
+	total = PAGE_SIZE << page_order;
+
+	byte_count = 0;
+	agp_offset = request.agp_start;
+
+	DRM_DEBUG( "count:      %d\n",  count );
+	DRM_DEBUG( "order:      %d\n",  order );
+	DRM_DEBUG( "size:       %d\n",  size );
+	DRM_DEBUG( "agp_offset: %lu\n", agp_offset );
+	DRM_DEBUG( "alignment:  %d\n",  alignment );
+	DRM_DEBUG( "page_order: %d\n",  page_order );
+	DRM_DEBUG( "total:      %d\n",  total );
+
+	if ( order < DRM_MIN_ORDER || order > DRM_MAX_ORDER ) return -EINVAL;
+	if ( dev->queue_count ) return -EBUSY; /* Not while in use */
+
+	spin_lock( &dev->count_lock );
+	if ( dev->buf_use ) {
+		spin_unlock( &dev->count_lock );
+		return -EBUSY;
+	}
+	atomic_inc( &dev->buf_alloc );
+	spin_unlock( &dev->count_lock );
+
+	down( &dev->struct_sem );
+	entry = &dma->bufs[order];
+	if ( entry->buf_count ) {
+		up( &dev->struct_sem );
+		atomic_dec( &dev->buf_alloc );
+		return -ENOMEM; /* May only call once for each order */
+	}
+
+	if (count < 0 || count > 4096) {
+		up( &dev->struct_sem );
+		atomic_dec( &dev->buf_alloc );
+		return -EINVAL;
+	}
+
+	entry->buflist = DRM(alloc)( count * sizeof(*entry->buflist),
+				    DRM_MEM_BUFS );
+	if ( !entry->buflist ) {
+		up( &dev->struct_sem );
+		atomic_dec( &dev->buf_alloc );
+		return -ENOMEM;
+	}
+	memset( entry->buflist, 0, count * sizeof(*entry->buflist) );
+
+	entry->buf_size = size;
+	entry->page_order = page_order;
+
+	offset = 0;
+
+	while ( entry->buf_count < count ) {
+		buf          = &entry->buflist[entry->buf_count];
+		buf->idx     = dma->buf_count + entry->buf_count;
+		buf->total   = alignment;
+		buf->order   = order;
+		buf->used    = 0;
+
+		buf->offset  = (dma->byte_count + offset);
+		buf->bus_address = agp_offset + offset;
+		buf->address = (void *)(agp_offset + offset);
+		buf->next    = NULL;
+		buf->waiting = 0;
+		buf->pending = 0;
+		init_waitqueue_head( &buf->dma_wait );
+		buf->filp    = NULL;
+
+		buf->dev_priv_size = dev->dev_priv_size;
+		buf->dev_private = DRM(alloc)( buf->dev_priv_size,
+					       DRM_MEM_BUFS );
+		if(!buf->dev_private) {
+			/* Set count correctly so we free the proper amount. */
+			entry->buf_count = count;
+			DRM(cleanup_buf_error)(dev,entry);
+			up( &dev->struct_sem );
+			atomic_dec( &dev->buf_alloc );
+			return -ENOMEM;
+		}
+		memset( buf->dev_private, 0, buf->dev_priv_size );
+
+		DRM_DEBUG( "buffer %d @ %p\n",
+			   entry->buf_count, buf->address );
+
+		offset += alignment;
+		entry->buf_count++;
+		byte_count += PAGE_SIZE << page_order;
+	}
+
+	DRM_DEBUG( "byte_count: %d\n", byte_count );
+
+	temp_buflist = DRM(realloc)( dma->buflist,
+				     dma->buf_count * sizeof(*dma->buflist),
+				     (dma->buf_count + entry->buf_count)
+				     * sizeof(*dma->buflist),
+				     DRM_MEM_BUFS );
+	if(!temp_buflist) {
+		/* Free the entry because it isn't valid */
+		DRM(cleanup_buf_error)(dev,entry);
+		up( &dev->struct_sem );
+		atomic_dec( &dev->buf_alloc );
+		return -ENOMEM;
+	}
+	dma->buflist = temp_buflist;
+
+	for ( i = 0 ; i < entry->buf_count ; i++ ) {
+		dma->buflist[i + dma->buf_count] = &entry->buflist[i];
+	}
+
+	dma->buf_count += entry->buf_count;
+	dma->byte_count += byte_count;
+
+	DRM_DEBUG( "dma->buf_count : %d\n", dma->buf_count );
+	DRM_DEBUG( "entry->buf_count : %d\n", entry->buf_count );
+
+	up( &dev->struct_sem );
+
+	request.count = entry->buf_count;
+	request.size = size;
+
+	if ( copy_to_user( argp, &request, sizeof(request) ) )
+		return -EFAULT;
+
+	dma->flags = _DRM_DMA_USE_FB;
+
+	atomic_dec( &dev->buf_alloc );
+	return 0;
+}
+
+
+
 /**
  * Add buffers for DMA transfers (ioctl).
  *
@@ -1028,8 +1197,10 @@ int DRM(addbufs)( struct inode *inode, struct file *filp,
 #endif
 	if ( request.flags & _DRM_SG_BUFFER )
 		return DRM(addbufs_sg)( inode, filp, cmd, arg );
-	else
-		return DRM(addbufs_pci)( inode, filp, cmd, arg );
+        else if ( request.flags & _DRM_FB_BUFFER )
+            return DRM(addbufs_fb)( inode, filp, cmd, arg );
+        else
+            return DRM(addbufs_pci)( inode, filp, cmd, arg );
 }
 
 
@@ -1273,7 +1444,8 @@ int DRM(mapbufs)( struct inode *inode, struct file *filp,
 
 	if ( request.count >= dma->buf_count ) {
 		if ((drm_core_has_AGP(dev) && (dma->flags & _DRM_DMA_USE_AGP)) ||
-		    (drm_core_check_feature(dev, DRIVER_SG) && (dma->flags & _DRM_DMA_USE_SG))) {
+                    (drm_core_check_feature(dev, DRIVER_SG) && (dma->flags & _DRM_DMA_USE_SG)) ||
+                    (drm_core_check_feature(dev, DRIVER_FB_DMA) && (dma->flags & _DRM_DMA_USE_FB))) {
 			drm_map_t *map = dev->agp_buffer_map;
 
 			if ( !map ) {