[QUESTION] omap iommu: a generic IOMMU?

[Ming Lei]

Hi,

On Sun, Nov 13, 2011 at 9:37 PM, Ohad Ben-Cohen <ohad at wizery.com> wrote:
> Hello,
>
> On Sun, Nov 13, 2011 at 1:04 PM, Ming Lei <tom.leiming at gmail.com> wrote:
>> Just be curious, is it a generic IOMMU so that it can be used by all IO
>> peripherals in OMAP4?
>
> No, it's a dedicated iommu for the DSP and dual-M3 subsystems.

Thanks for your clarification.

>> From related source code[1] and OMAP4 TRM[2], looks like the omap iommu
>> only belongs to Cortex-M3 MPU subsystem inside OMAP4 chip, so I am wondering
>> why introduces the driver for arm v7 based linux kernel...
>
> Because we control the iommus from the A9 (which is running Linux..) :)

Could you give a use case about the usage of controlling the iommu from
the A9? Or the advantage of doing this?

I understand that the M3 and DSP can do this too, :-)

thanks,
-- 
Ming Lei