On Wed, Feb 4, 2015 at 1:54 PM, Olav Haugan <[email protected]> wrote:
> Adding Mitch H. and Rob Clark.
>

The current upstream msm-iommu isn't actually used by anything,
afaict.. it lacks support for DT based platforms.  So this is fine by
me.

Acked-by: Rob Clark <[email protected]>


>
> On 2/3/2015 11:58 PM, Thierry Reding wrote:
>>
>> From: Thierry Reding <[email protected]>
>>
>> The MSM IOMMU driver unconditionally calls bus_set_iommu(), which is a
>> very stupid thing to do on multi-platform kernels. While marking the
>> driver BROKEN may seem a little extreme, there is no other way to make
>> the driver skip initialization. One of the problems is that it doesn't
>> have devicetree binding documentation and the driver doesn't contain a
>> struct of_device_id table either, so no way to check that it is indeed
>> valid to set up the IOMMU operations for this driver.
>>
>> This fixes a problem on Tegra20 where the DRM driver will try to use the
>> obviously non-existent MSM IOMMU.
>>
>> Marking the driver BROKEN shouldn't do any harm, since there aren't any
>> users currently. There is no struct of_device_id table, so the device
>> can't be instantiated from device tree, and I couldn't find any code
>> that would instantiate a matching platform_device either, so the driver
>> is effectively unused.
>>
>> Reported-by: Nicolas Chauvet <[email protected]>
>> Cc: David Brown <[email protected]>
>> Cc: Daniel Walker <[email protected]>
>> Cc: Bryan Huntsman <[email protected]>
>> Cc: Olav Haugan <[email protected]>
>> Signed-off-by: Thierry Reding <[email protected]>
>> ---
>>   drivers/iommu/Kconfig | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
>> index 325188eef1c1..0f70bc1fce65 100644
>> --- a/drivers/iommu/Kconfig
>> +++ b/drivers/iommu/Kconfig
>> @@ -31,6 +31,7 @@ config FSL_PAMU
>>   config MSM_IOMMU
>>         bool "MSM IOMMU Support"
>>         depends on ARCH_MSM8X60 || ARCH_MSM8960
>> +       depends on BROKEN
>>         select IOMMU_API
>>         help
>>           Support for the IOMMUs found on certain Qualcomm SOCs.
>>
>
>
> .Olav
>
> --
> Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
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