Re: [PATCHv4 4/4] iommu: create new api to set valid da range

[Hiroshi DOYU]

From: ext Felipe Contreras <felipe.contreras@xxxxxxxxx>
Subject: Re: [PATCHv4 4/4] iommu: create new api to set valid da range
Date: Wed, 20 Oct 2010 10:58:16 +0200

> On Wed, Oct 20, 2010 at 11:45 AM, Hiroshi DOYU <Hiroshi.DOYU@xxxxxxxxx> wrote:
>> From: "ext felipe.contreras@xxxxxxxxx" <felipe.contreras@xxxxxxxxx>
>> Subject: Re: [PATCHv4 4/4] iommu: create new api to set valid da range
>> Date: Wed, 20 Oct 2010 10:35:50 +0200
>>
>>> On Wed, Oct 20, 2010 at 5:48 AM, Fernando Guzman Lugo <x0095840@xxxxxx> wrote:
>>>> Some IOMMUs cannot use the whole 0x0 - 0xFFFFFFFF range.
>>>> With this new API the valid range can be set.
>>>>
>>>> Signed-off-by: Fernando Guzman Lugo <x0095840@xxxxxx>
>>>
>>> I don't see the point in having an API. It could be done through
>>> platform data, and the usage of 0xFFFFF000 instead of ULONG_MAX is
>>> independent of this.
>>
>> Using platform data is better, but why dropping da_end?
> 
> Because it's always 0xFFFFF000. Do you know of any instance where
>it's not?

We should try to avoid forcing unnecessary limitations and
dependencies. The usage of device virtual address space range depends
on dsp(coprocessor) side S/W implimentation or configuration.
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