[PATCH 1/2] omap: iommu: make iva2 iommu selectable

[Felipe Contreras]

On Mon, Oct 11, 2010 at 6:54 PM, Guzman Lugo, Fernando
<fernando.lugo at ti.com> wrote:
>> Once the iommu migration works (haven't managed to get it
>> working myself), and it has been merged into mainline, then
>> we can think about enabling it unconditionally. In the
>> meantime, enabling unconditionally would break the
>> tidspbridge that is in staging (mainline).
>
> What is the problem enabling unconditionally?
>
> The iva2 iommu does not start working until you call iommu_get.
> So if for some reason you are using the dspbridge with custom
> Iommu implementation it should not cause any collision with
> Iommu module.

Read the code below (omap_iommu_init), the resources are registered so
nobody else can use them. This caused problems multiple times inside
Nokia, which is what motivated to write the patch in the first
place[1].

[1] http://thread.gmane.org/gmane.linux.ports.arm.kernel/58302/focus=58305

-- 
Felipe Contreras