Re: [PATCH 08/10] iommu/omap: Use bus_set_iommu instead ofregister_iommu

From: Roedel, Joerg
Date: Tue Sep 27 2011 - 07:00:41 EST


On Mon, Sep 26, 2011 at 08:29:04AM -0400, Ohad Ben-Cohen wrote:
> On Mon, Sep 26, 2011 at 3:22 PM, Roedel, Joerg <Joerg.Roedel@xxxxxxx> wrote:
> > That is interesting. What bus do these IOMMU users you talk about belong
> > to?
>
> E.g., virtio devices (which today originates from a platform device)
> or even rpmsg users (which originates from the former virtio devices).
>
> > Is it a seperate bus that originates from a platform device?
>
> Yes.
>
> > in that
> > case the situation sounds a little bit like with USB on x86. The usb
> > controlers are PCI devices and DMA handles are allocated using the
> > pci_dev of the controler and not the usb_device.
>
> Yeah, sounds very similar.

The question is, of course, if the IOMMU on the platform device can
identify single devices on the bus that originates from it? That would
be an important difference to the PCI->USB case.

Joerg

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