[PATCH 1/7] drm/prime: introduce sg->pages/addr arrays helper

[Alex Deucher]

On Tue, May 22, 2012 at 8:49 AM, Dave Airlie <airlied at gmail.com> wrote:
> From: Dave Airlie <airlied at redhat.com>
>
> 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.
>
> Signed-off-by: Dave Airlie <airlied at redhat.com>

Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/drm_prime.c |   36 ++++++++++++++++++++++++++++++++++++
>  include/drm/drmP.h          |    2 ++
>  2 files changed, 38 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index 1bdf2b5..20dbf2c 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -227,6 +227,42 @@ out:
>  }
>  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)
>  {
> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index 15d9179..31ad880 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -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);
>
> --
> 1.7.6
>
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