minigbm: add drv_bo_flush

As an optimization, we would like to separate buffer flush/writeback
and unmap. This patch adds the appropriate entry point in our
internal driver API. Overall, the proposed flow is:

	- drv_bo_map(..) creates a mapping and associated metadata
	- drv_bo_flush(..) writes memory from any cache or temporary
          buffer back to memory
        - drv_bo_unmap(..) flushes, and frees the mapping and
	  associated metadata.

The drv_bo_flush function just does some sanity checks on
the map data at this point, but otherwise is a no-op.

BUG=chromium:764871
TEST=gbmtest, mmap_test -g on eve

Change-Id: If306f066a76bc5e0943c1170e2d6933fa5630eff
Reviewed-on: https://chromium-review.googlesource.com/668218
Commit-Ready: Gurchetan Singh <gurchetansingh@chromium.org>
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/drv.h b/drv.h
index e4678a1..f9a7a87 100644
--- a/drv.h
+++ b/drv.h
@@ -113,7 +113,9 @@ struct bo *drv_bo_import(struct driver *drv, struct drv_import_fd_data *data);
 void *drv_bo_map(struct bo *bo, uint32_t x, uint32_t y, uint32_t width, uint32_t height,
 		 uint32_t flags, struct map_info **map_data, size_t plane);
 
-int drv_bo_unmap(struct bo *bo, struct map_info *map_data);
+int drv_bo_unmap(struct bo *bo, struct map_info *data);
+
+int drv_bo_flush(struct bo *bo, struct map_info *data);
 
 uint32_t drv_bo_get_width(struct bo *bo);