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From: Joerg Roedel <joro@8bytes.org>
Newsgroups: linux.kernel
Subject: Re: [PATCH 2/5] iommu/omap: Permanently keep iommu_dev pointer in  arch_data
Date: Fri, 07 Apr 2017 16:40:02 +0200
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Hi Suman,

On Mon, Apr 03, 2017 at 03:35:46PM -0500, Suman Anna wrote:
> > +	iommu = platform_get_drvdata(pdev);
> > +	if (!iommu) {
> > +		of_node_put(np);
> > +		return -EINVAL;
> > +	}
> 
> This change is causing the issues. OMAP IOMMU driver is not probed yet,
> but this gets called during the driver's init function in
> bus_set_iommu() and bus's iommu_ops gets set to NULL. The add_device
> today is used to add the linking to an IOMMU device (currently name
> primarily to support the legacy non-DT mode which is no longer an issue,
> but a dev pointer can be used instead here, and the real enabling is
> done during the domain's attach_dev callback.

Yeah, okay. Solving this problem requires more sophisticated handling in
the iommu core code, which is not implemented yet.

I drop this patch for now and do the device-linking and group-handling
in attach_dev. This makes iommu-groups on omap useless for now, but it
is a start.


	Joerg