Re: [PATCH v2 1/2] [RFC] ARM: IOMMU: Tegra20: iommu_ops for GART driver

[Joerg Roedel <joerg.roedel@amd.com>]

On Thu, Dec 15, 2011 at 03:11:29PM +0200, Hiroshi DOYU wrote:
> Tegra 20 IOMMU H/W, GART (Graphics Address Relocation Table). This
> patch implements struct iommu_ops for GART for the upper IOMMU API.
> 
> This H/W module supports only single virtual address space(domain),
> and manages a single level 1-to-1 mapping H/W translation page table.
> 
> Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
> ---
>  drivers/iommu/Kconfig      |   11 +
>  drivers/iommu/Makefile     |    1 +
>  drivers/iommu/tegra-gart.c |  451 ++++++++++++++++++++++++++++++++++++++++++++

The code looks good in general. I think we need to extend the IOMMU-API
a little bit to better support GART IOMMUs. A user of the IOMMU-API
should be able to get the information about the iova-base and size of
the aperture for example. These extensions will be beneficial for
porting other GART-like driver to the IOMMU-API too.


	Joerg

-- 
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632