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Commit f3bc9d24 authored by Rob Clark's avatar Rob Clark Committed by Greg Kroah-Hartman
Browse files

drm/omap: GEM, deal with cache 



Uncached/writecombine buffers need to be clean before creating uc/wc
userspace mappings, lest dirty cache lines fall down and corrupt the
contents of the buffer.

Signed-off-by: default avatarRob Clark <rob@ti.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent c25b3c9a

drivers/staging/omapdrm/omap_gem.c

+30 −0
Original line number Diff line number Diff line
@@ -84,6 +84,9 @@ struct omap_gem_object { 
	 */

	struct page **pages;



	/** addresses corresponding to pages in above array */

	dma_addr_t *addrs;



	/**

	 * Virtual address, if mapped.

	 */
@@ -208,6 +211,19 @@ static int omap_gem_attach_pages(struct drm_gem_object *obj) 
		return PTR_ERR(pages);

	}



	/* for non-cached buffers, ensure the new pages are clean because

	 * DSS, GPU, etc. are not cache coherent:

	 */

	if (omap_obj->flags & (OMAP_BO_WC|OMAP_BO_UNCACHED)) {

		int i, npages = obj->size >> PAGE_SHIFT;

		dma_addr_t *addrs = kmalloc(npages * sizeof(addrs), GFP_KERNEL);

		for (i = 0; i < npages; i++) {

			addrs[i] = dma_map_page(obj->dev->dev, pages[i],

					0, PAGE_SIZE, DMA_BIDIRECTIONAL);

		}

		omap_obj->addrs = addrs;

	}



	omap_obj->pages = pages;

	return 0;

}
@@ -216,6 +232,20 @@ static int omap_gem_attach_pages(struct drm_gem_object *obj) 
static void omap_gem_detach_pages(struct drm_gem_object *obj)

{

	struct omap_gem_object *omap_obj = to_omap_bo(obj);



	/* for non-cached buffers, ensure the new pages are clean because

	 * DSS, GPU, etc. are not cache coherent:

	 */

	if (omap_obj->flags & (OMAP_BO_WC|OMAP_BO_UNCACHED)) {

		int i, npages = obj->size >> PAGE_SHIFT;

		for (i = 0; i < npages; i++) {

			dma_unmap_page(obj->dev->dev, omap_obj->addrs[i],

					PAGE_SIZE, DMA_BIDIRECTIONAL);

		}

		kfree(omap_obj->addrs);

		omap_obj->addrs = NULL;

	}



	_drm_gem_put_pages(obj, omap_obj->pages, true, false);

	omap_obj->pages = NULL;

}