RE: [PATCH 02/10] Driver core: Add iommu_ops to bus_type

Sethi Varun-B16395
2011-09-12T11:40:15Z

> -----Original Message-----
> From: kvm-owner@vger.kernel.org [mailto:kvm-owner@vger.kernel.org] On
> Behalf Of Joerg Roedel
> Sent: Thursday, September 08, 2011 2:12 PM
> To: Greg KH
> Cc: Joerg Roedel; iommu@lists.linux-foundation.org; Alex Williamson; Ohad
> Ben-Cohen; David Woodhouse; David Brown; kvm@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH 02/10] Driver core: Add iommu_ops to bus_type
>
> On Wed, Sep 07, 2011 at 12:44:45PM -0700, Greg KH wrote:
> > On Wed, Sep 07, 2011 at 09:19:19PM +0200, Joerg Roedel wrote:
> > > Hi Greg,
> > >
> > > the bus_set_iommu() function will be called by the IOMMU driver.
> > > There can be different drivers for the same bus, depending on the
> > > hardware. On PCI for example, there can be the Intel or the AMD
> > > IOMMU driver that implement the iommu-api and that register for that
> bus.
> >
> > Why are you pushing this down into the driver core? What other busses
> > becides PCI use/need this?
>
> Currently it is the platform_bus besides pci. The pci iommus are on x86
> and ia64 while all arm iommus use the platform_bus (by 'iommus' I only
> mean those implementing the iommu-api). Currently there are two drivers
> for arm iommus in /drivers/iommu.
>
We too have an IOMMU on Freescale Socs (Power core based) sitting on the platform bus
and are looking at integrating it with the linux IOMMU API.

-Varun