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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: Rob Clark <rob@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Rob Clark 2011-12-20 16:54:28 -06:00 committed by Greg Kroah-Hartman
parent c25b3c9a43
commit f3bc9d24cb
1 changed files with 30 additions and 0 deletions
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30
drivers/staging/omapdrm/omap_gem.c
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@ -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;
}