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

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

Hi Christian

Am 29.09.20 um 17:35 schrieb Christian König:
> 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?

As Daniel mentioned, it's in patch 3. The TTM-based drivers will
retrieve the pointer via this function.

I do want to see all that being more tightly integrated into TTM, but
not in this series. This one is about fixing the bochs-on-sparc64
problem for good. Patch 7 adds an update to TTM to the DRM TODO list.

Best regards
Thomas

> 
> Regards,
> Christian.
> 
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
>> ---
>>   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
> 
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-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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