Date: Fri, 27 Nov 2015 13:02:03 +0100
From: Joerg Roedel <joro@8bytes.org>
To: Chen Feng <puck.chen@hisilicon.com>
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
        robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com,
        ijc+devicetree@hellion.org.uk, devicetree@vger.kernel.org,
        puck.chen@aliyun.com, w.f@huawei.com, xuwei5@hisilicon.com,
        guodong.xu@linaro.org, arnd@linaro.org, haojian.zhuang@linaro.org
Subject: Re: [PATCH V5 RESEND 2/3] iommu/hisilicon: Add hi6220-SoC smmu driver
Message-ID: <20151127120203.GI24300@8bytes.org>
References: <1447986309-47548-1-git-send-email-puck.chen@hisilicon.com>
 <1447986309-47548-3-git-send-email-puck.chen@hisilicon.com>
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On Fri, Nov 20, 2015 at 10:25:08AM +0800, Chen Feng wrote:
> +config HI6220_IOMMU
> +	bool "Hi6220 IOMMU Support"
> +	depends on ARM64
> +	select IOMMU_API
> +	select IOMMU_IOVA
> +	help
> +	  Enable IOMMU Driver for hi6220 SoC. The IOMMU API and IOMMU IOVA
> +	  is also selected.

The last sentence is of little help for the user. Better put the reasons
in here when a user should select this option.

> +	/*set axi id*/

Coding style nit: Please write these oneline comments with spaces, like
this:

	/* set axi id */

> +static int hi6220_smmu_attach_dev(struct iommu_domain *domain,
> +				  struct device *dev)
> +{
> +	dev->archdata.iommu = &iova_allocator;
> +
> +	return 0;
> +}
> +
> +static void hi6220_smmu_detach_dev(struct iommu_domain *domain,
> +				   struct device *dev)
> +{
> +	dev->archdata.iommu = NULL;
> +}

This basically means that this driver only supports one domain, right?
That is not compatible with the iommu-api requirements.

You need to create an iommu-group per smmu in your system and put all
devices translated by this smmu in that group. And then you must change
your code to allow attaching/detaching this iommu-group to different
domains.


	Joerg

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