[PATCH v5 1/1] iommu-api: Add map_sg/unmap_sg functions

[Rob Clark]

On Mon, Aug 11, 2014 at 9:51 PM, Hiroshi Doyu <hdoyu at nvidia.com> wrote:
> Hi Olav,
>
> Olav Haugan <ohaugan at codeaurora.org> writes:
>
>> @@ -93,6 +94,10 @@ enum iommu_attr {
>>   * @detach_dev: detach device from an iommu domain
>>   * @map: map a physically contiguous memory region to an iommu domain
>>   * @unmap: unmap a physically contiguous memory region from an iommu domain
>> + * @map_sg: map a scatter-gather list of physically contiguous memory chunks
>> + * to an iommu domain
>> + * @unmap_sg: unmap a scatter-gather list of physically contiguous memory
>> + * chunks from an iommu domain
>>   * @iova_to_phys: translate iova to physical address
>>   * @domain_has_cap: domain capabilities query
>>   * @add_device: add device to iommu grouping
>> @@ -110,6 +115,11 @@ struct iommu_ops {
>>                    phys_addr_t paddr, size_t size, int prot);
>>         size_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
>>                      size_t size);
>> +       int (*map_sg)(struct iommu_domain *domain, unsigned long iova,
>> +                       struct scatterlist *sg, unsigned int nents, int prot,
>> +                       unsigned long flags);
>> +       int (*unmap_sg)(struct iommu_domain *domain, unsigned long iova,
>> +                       size_t size, unsigned long flags);
>
> Do you have any exmaple/explanation for the above "flags"?
>
> Is this going to be used for iommu global/standard attribute or SoC
> spcific one?

iirc, one plan for 'flags' was some sort of DONT_FLUSH_TLB flag for
drivers which wanted to map/unmap N buffers with a single flush at the
end.  There might have been some other usages envisioned.

BR,
-R