[PATCH v4 05/12] memory: Add NVIDIA Tegra memory controller support

Thierry Reding thierry.reding at gmail.com
Thu Oct 30 07:56:56 PDT 2014


On Thu, Oct 30, 2014 at 03:47:59PM +0200, Terje Bergström wrote:
> On 30.10.2014 15:35, Alexandre Courbot wrote:
> > Great, thanks for confirming!
> > 
> > Thierry, how do you want to address this? We could change the register
> > for the GPU group, or (maybe preferable if we want to reflect the actual
> > hardware state) add the GPUB group. I don't know if that would be easy
> > though since we would have the problem of the gpusrd and gpuswr clients
> > ownership (seems like they would belong to both groups?)
> 
> gpusrd and gpuswr are client IDs for GPU reads and writes on MC. GPU and
> GPUB are SW group IDs for SMMU. There's no 1:1 or hierarchical mapping.

Since the GPU client ID is effectively useless for purposes of IOMMU
translation I'd lean towards just keeping the existing TEGRA_SWGROUP_GPU
and update the register to point to MC_SMMU_GPUB_ASID_0.

Thierry
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