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Date:   Mon, 28 Nov 2022 13:59:30 +0000
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Subject: Re: [PATCH v3 06/20] iommu/mtk: Remove detach_dev callback
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To:     Jason Gunthorpe <jgg@nvidia.com>,
        Lu Baolu <baolu.lu@linux.intel.com>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Christoph Hellwig <hch@infradead.org>,
        Kevin Tian <kevin.tian@intel.com>,
        Will Deacon <will@kernel.org>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
        Hector Martin <marcan@marcan.st>,
        Sven Peter <sven@svenpeter.dev>,
        Rob Clark <robdclark@gmail.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
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        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Yong Wu <yong.wu@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Heiko Stuebner <heiko@sntech.de>,
        Matthew Rosato <mjrosato@linux.ibm.com>,
        Orson Zhai <orsonzhai@gmail.com>,
        Baolin Wang <baolin.wang@linux.alibaba.com>,
        Chunyan Zhang <zhang.lyra@gmail.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        iommu@lists.linux.dev, linux-kernel@vger.kernel.org
References: <20221128064648.1934720-1-baolu.lu@linux.intel.com>
 <20221128064648.1934720-7-baolu.lu@linux.intel.com>
 <Y4S8elzfzdTJGtyK@nvidia.com>
From:   Robin Murphy <robin.murphy@arm.com>
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On 2022-11-28 13:49, Jason Gunthorpe wrote:
> On Mon, Nov 28, 2022 at 02:46:34PM +0800, Lu Baolu wrote:
>> The IOMMU driver supports default domain, so the detach_dev op will never
>> be called. Remove it to avoid dead code.
>>
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>> ---
>>   drivers/iommu/mtk_iommu.c | 9 ---------
>>   1 file changed, 9 deletions(-)
> 
> I listed this driver as not supporting default domains:
> 
> https://lore.kernel.org/linux-iommu/20220516135741.GV1343366@nvidia.com/
> 
> ?
> 
> Has something changed? Did I get it wrong?

static struct iommu_domain *mtk_iommu_domain_alloc(unsigned type)
{
	struct mtk_iommu_domain *dom;

	if (type != IOMMU_DOMAIN_DMA && type != IOMMU_DOMAIN_UNMANAGED)
		return NULL;
...


This one runs on arm64, so has always supported default domains for 
iommu-dma to work.

Cheers,
Robin.