From: Joerg Roedel <joro@8bytes.org>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org,
Jon Hunter <jonathanh@nvidia.com>
Subject: Re: [PATCH] iommu: Do not probe devices on IOMMU-less busses
Date: Wed, 13 May 2020 10:42:50 +0200 [thread overview]
Message-ID: <20200513084250.GC9820@8bytes.org> (raw)
In-Reply-To: <20200511161000.3853342-1-thierry.reding@gmail.com>
On Mon, May 11, 2020 at 06:10:00PM +0200, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
>
> The host1x bus implemented on Tegra SoCs is primarily an abstraction to
> create logical device from multiple platform devices. Since the devices
> in such a setup are typically hierarchical, DMA setup still needs to be
> done so that DMA masks can be properly inherited, but we don't actually
> want to attach the host1x logical devices to any IOMMU. The platform
> devices that make up the logical device are responsible for memory bus
> transactions, so it is them that will need to be attached to the IOMMU.
>
> Add a check to __iommu_probe_device() that aborts IOMMU setup early for
> busses that don't have the IOMMU operations pointer set since they will
> cause a crash otherwise.
>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
> Note that this is probably also required for the BCMA bus implemented in
> drivers/bcma/main.c since no IOMMU operations are ever assigned to that
> either.
>
> drivers/iommu/iommu.c | 3 +++
> 1 file changed, 3 insertions(+)
Applied, thanks.
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prev parent reply other threads:[~2020-05-13 8:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 16:10 [PATCH] iommu: Do not probe devices on IOMMU-less busses Thierry Reding
2020-05-13 8:42 ` Joerg Roedel [this message]
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