Re: [PATCH v3 2/7] drm/ttm: Add ttm_kmap_obj_to_dma_buf_map() for type conversion

["Christian König" <christian.koenig@amd.com>]

Am 29.09.20 um 17:14 schrieb Thomas Zimmermann:
> The new helper ttm_kmap_obj_to_dma_buf() extracts address and location
> from and instance of TTM's kmap_obj and initializes struct dma_buf_map
> with these values. Helpful for TTM-based drivers.

We could completely drop that if we use the same structure inside TTM as 
well.

Additional to that which driver is going to use this?

Regards,
Christian.

>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>   include/drm/ttm/ttm_bo_api.h | 24 ++++++++++++++++++++++++
>   include/linux/dma-buf-map.h  | 20 ++++++++++++++++++++
>   2 files changed, 44 insertions(+)
>
> diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
> index c96a25d571c8..62d89f05a801 100644
> --- a/include/drm/ttm/ttm_bo_api.h
> +++ b/include/drm/ttm/ttm_bo_api.h
> @@ -34,6 +34,7 @@
>   #include <drm/drm_gem.h>
>   #include <drm/drm_hashtab.h>
>   #include <drm/drm_vma_manager.h>
> +#include <linux/dma-buf-map.h>
>   #include <linux/kref.h>
>   #include <linux/list.h>
>   #include <linux/wait.h>
> @@ -486,6 +487,29 @@ static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map,
>   	return map->virtual;
>   }
>   
> +/**
> + * ttm_kmap_obj_to_dma_buf_map
> + *
> + * @kmap: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap.
> + * @map: Returns the mapping as struct dma_buf_map
> + *
> + * Converts struct ttm_bo_kmap_obj to struct dma_buf_map. If the memory
> + * is not mapped, the returned mapping is initialized to NULL.
> + */
> +static inline void ttm_kmap_obj_to_dma_buf_map(struct ttm_bo_kmap_obj *kmap,
> +					       struct dma_buf_map *map)
> +{
> +	bool is_iomem;
> +	void *vaddr = ttm_kmap_obj_virtual(kmap, &is_iomem);
> +
> +	if (!vaddr)
> +		dma_buf_map_clear(map);
> +	else if (is_iomem)
> +		dma_buf_map_set_vaddr_iomem(map, (void __force __iomem *)vaddr);
> +	else
> +		dma_buf_map_set_vaddr(map, vaddr);
> +}
> +
>   /**
>    * ttm_bo_kmap
>    *
> diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
> index fd1aba545fdf..2e8bbecb5091 100644
> --- a/include/linux/dma-buf-map.h
> +++ b/include/linux/dma-buf-map.h
> @@ -45,6 +45,12 @@
>    *
>    *	dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
>    *
> + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
> + *
> + * .. code-block:: c
> + *
> + *	dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
> + *
>    * Test if a mapping is valid with either dma_buf_map_is_set() or
>    * dma_buf_map_is_null().
>    *
> @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct dma_buf_map *map, void *vaddr)
>   	map->is_iomem = false;
>   }
>   
> +/**
> + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to an address in I/O memory
> + * @map:		The dma-buf mapping structure
> + * @vaddr_iomem:	An I/O-memory address
> + *
> + * Sets the address and the I/O-memory flag.
> + */
> +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
> +					       void __iomem *vaddr_iomem)
> +{
> +	map->vaddr_iomem = vaddr_iomem;
> +	map->is_iomem = true;
> +}
> +
>   /**
>    * dma_buf_map_is_equal - Compares two dma-buf mapping structures for equality
>    * @lhs:	The dma-buf mapping structure