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Date:   Tue, 29 Sep 2020 22:39:31 -0700
From:   Nicolin Chen <nicoleotsuka@gmail.com>
To:     Dmitry Osipenko <digetx@gmail.com>
Cc:     thierry.reding@gmail.com, joro@8bytes.org, krzk@kernel.org,
        vdumpa@nvidia.com, jonathanh@nvidia.com,
        linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] iommu/tegra-smmu: Rework .probe_device and
 .attach_dev
Message-ID: <20200930053930.GD31821@Asurada-Nvidia>
References: <20200930003013.31289-1-nicoleotsuka@gmail.com>
 <20200930003013.31289-3-nicoleotsuka@gmail.com>
 <03710107-b6ad-5256-4550-09c610d0fded@gmail.com>
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On Wed, Sep 30, 2020 at 08:24:02AM +0300, Dmitry Osipenko wrote:
> 30.09.2020 03:30, Nicolin Chen пишет:
> > +	/*
> > +	 * IOMMU core allows -ENODEV return to carry on. So bypass any call
> > +	 * from bus_set_iommu() during tegra_smmu_probe(), as a device will
> > +	 * call in again via of_iommu_configure when fwspec is prepared.
> > +	 */
> > +	if (!mc->smmu || !fwspec || fwspec->ops != &tegra_smmu_ops)
> >  		return ERR_PTR(-ENODEV);
> 
> The !mc->smmu can't be true.

Are you sure? I have removed the "mc->smmu = smmu" in probe() with
this change. So the only time "mc->smmu == !NULL" is after probe()
of SMMU driver is returned. As my comments says, tegra_smmu_probe()
calls in this function via bus_set_iommu(), so mc->smmu can be NULL
in this case.