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Date:   Thu, 9 Apr 2020 16:30:59 +0200
From:   Joerg Roedel <joro@8bytes.org>
To:     Marek Szyprowski <m.szyprowski@samsung.com>
Cc:     Will Deacon <will@kernel.org>, Robin Murphy <robin.murphy@arm.com>,
        Kukjin Kim <kgene@kernel.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        David Woodhouse <dwmw2@infradead.org>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Rob Clark <robdclark@gmail.com>,
        Heiko Stuebner <heiko@sntech.de>,
        Gerald Schaefer <gerald.schaefer@de.ibm.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
        linux-samsung-soc@vger.kernel.org, linux-arm-msm@vger.kernel.org,
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        linux-tegra@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
        Joerg Roedel <jroedel@suse.de>
Subject: Re: [PATCH] iommu/exynos: Get rid of 'struct exynos_iommu_owner'
 exynos_iommu_owner
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Hi Marek,

On Thu, Apr 09, 2020 at 03:58:00PM +0200, Marek Szyprowski wrote:
> The main problem after your conversion is the fact that ->probe_device() 
> is called very early, before any other platform device (thus IOMMU 
> controller) is is probed. It doesn't handle EPROBE_DEFER too.

I don't quite understand why probe_device() is called too early, as it
is called at the same time add_device() was called before. But anyway,
I have seen a similar problem on OMAP. If the SYSMMU for a master is not
probed yet when probe_device() is called, it can just return -ENODEV and
in your driver you just call but_iommu_probe() when a new SYSMMU got
initialized to re-probe uninitialized masters on the bus. This patch-set
contains a change to export bus_iommu_probe() for exactly that reason.

What do you think?

Regards,

	Joerg