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

[Roedel, Joerg]

On Mon, Sep 26, 2011 at 03:09:58AM -0400, Ohad Ben-Cohen wrote:
> On Fri, Sep 23, 2011 at 6:45 PM, Joerg Roedel <joerg.roedel@xxxxxxx> wrote:
> > -       register_iommu(&omap_iommu_ops);
> > +       bus_set_iommu(&platform_bus_type, &omap_iommu_ops);
> 
> I'm not sure it makes a lot of sense to bind the iommu ops to the platform bus.
> 
> Unlike the pci bus, the platform bus is not really a hardware bus:
> it's some kind of a catch-all pseudo bus which is mostly used to to
> describe a collection of autonomous peripherals on an SoC.
> 
> As a result, IOMMU users on an SoC might actually not belong to the
> platform bus.

That is interesting. What bus do these IOMMU users you talk about belong
to?
Is it a seperate bus that originates from a platform device? 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.

Regards,

	Joerg

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