[PATCH 1/2] mmc: host: arasan: Add addition of-arasan quirks and add IOMMU support.

[Suman Tripathi]

Hi Arnd,

On Monday 15 December 2014 22:31:06 Suman Tripathi wrote:
> @@ -162,6 +206,16 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>                 goto clk_dis_ahb;
>         }
>
> +#if defined(CONFIG_IOMMU_SUPPORT)
> +       sdhci_arasan->domain = iommu_domain_alloc(&amba_bustype);
> +       if (!sdhci_arasan->domain) {
> +               dev_err(&pdev->dev, "Unable to allocate iommu domain\n");
> +               return PTR_ERR(sdhci_arasan->domain);
> +       }
> +
> +       iommu_attach_device(sdhci_arasan->domain, &pdev->dev);
> +#endif
> +
>

Device drivers should never care about the implementation details
of the iommu. Please change the code to use the regular dma_map_*
interfaces that will work both with and without IOMMU.

After refer to iommu binding , there is a service that allows "Remap
address space to allow devices to access physical memory ranges that
they otherwise wouldn't be capable of accessing." eg : 32-bit to 64
bit DMA .

So do we have any existing driver that uses this service ? Just asking
for suggestions.

On Tue, Dec 16, 2014 at 2:57 AM, Arnd Bergmann <arnd at arndb.de> wrote:
> On Monday 15 December 2014 22:31:06 Suman Tripathi wrote:
>> @@ -162,6 +206,16 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>>                 goto clk_dis_ahb;
>>         }
>>
>> +#if defined(CONFIG_IOMMU_SUPPORT)
>> +       sdhci_arasan->domain = iommu_domain_alloc(&amba_bustype);
>> +       if (!sdhci_arasan->domain) {
>> +               dev_err(&pdev->dev, "Unable to allocate iommu domain\n");
>> +               return PTR_ERR(sdhci_arasan->domain);
>> +       }
>> +
>> +       iommu_attach_device(sdhci_arasan->domain, &pdev->dev);
>> +#endif
>> +
>>
>
> Device drivers should never care about the implementation details
> of the iommu. Please change the code to use the regular dma_map_*
> interfaces that will work both with and without IOMMU.
>
>         Arnd



-- 
Thanks,
with regards,
Suman Tripathi
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