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Subject: Re: [PATCH] iommu: SUN50I_IOMMU should depend on HAS_DMA
To:     Joerg Roedel <joro@8bytes.org>
Cc:     Geert Uytterhoeven <geert@linux-m68k.org>,
        Maxime Ripard <maxime@cerno.tech>,
        iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
References: <20200629121146.24011-1-geert@linux-m68k.org>
 <c2047394-ea6e-3bc3-4bf0-a732237dbeca@arm.com>
 <20200630100947.GL28824@8bytes.org>
From:   Robin Murphy <robin.murphy@arm.com>
Message-ID: <e66478ff-1df0-8f3a-b164-76a430eca58b@arm.com>
Date:   Tue, 30 Jun 2020 11:49:06 +0100
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On 2020-06-30 11:09, Joerg Roedel wrote:
> On Mon, Jun 29, 2020 at 05:29:36PM +0100, Robin Murphy wrote:
>> On 2020-06-29 13:11, Geert Uytterhoeven wrote:
>>> If NO_DMA=y (e.g. Sun-3 all{mod,yes}-config):
>>>
>>>       drivers/iommu/dma-iommu.o: In function `iommu_dma_mmap':
>>>       dma-iommu.c:(.text+0x92e): undefined reference to `dma_pgprot'
>>>
>>> IOMMU_DMA must not be selected, unless HAS_DMA=y.
>>
>> Wait, no, IOMMU_DMA should not be selected by drivers at all - it's for arch
>> code to choose.
> 
> Okay, but that is a different fix, right? I queued this patch for v5.8
> for now.

If the driver didn't select IOMMU_DMA (completely unnecessarily, I might 
add), there wouldn't be any problem to fix in the first place ;)

Robin.