drm/prime: introduce sg->pages/addr arrays helper

the ttm drivers need this currently, in order to get fault handling
working and efficient.

It also allows addrs to be NULL for devices like udl.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Dave Airlie 2012-05-18 15:40:33 +01:00
parent 4d93914ae3
commit 51ab7ba267
2 changed files with 38 additions and 0 deletions

View file

@ -227,6 +227,42 @@ struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
}
EXPORT_SYMBOL(drm_prime_pages_to_sg);
/* export an sg table into an array of pages and addresses
this is currently required by the TTM driver in order to do correct fault
handling */
int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
dma_addr_t *addrs, int max_pages)
{
unsigned count;
struct scatterlist *sg;
struct page *page;
u32 len, offset;
int pg_index;
dma_addr_t addr;
pg_index = 0;
for_each_sg(sgt->sgl, sg, sgt->nents, count) {
len = sg->length;
offset = sg->offset;
page = sg_page(sg);
addr = sg_dma_address(sg);
while (len > 0) {
if (WARN_ON(pg_index >= max_pages))
return -1;
pages[pg_index] = page;
if (addrs)
addrs[pg_index] = addr;
page++;
addr += PAGE_SIZE;
len -= PAGE_SIZE;
pg_index++;
}
}
return 0;
}
EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
/* helper function to cleanup a GEM/prime object */
void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
{

View file

@ -1558,6 +1558,8 @@ extern int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
extern int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv);
extern int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
dma_addr_t *addrs, int max_pages);
extern struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages);
extern void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg);