[PATCH v2 14/22] iommu/tegra: smmu: Register platform_device to IOMMU dynamically

[Hiroshi Doyu]

Stephen Warren <swarren at wwwdotorg.org> wrote @ Thu, 18 Jul 2013 22:17:21 +0200:

> On 07/05/2013 04:44 AM, Hiroshi Doyu wrote:
> > Register platform_devices to IOMMU dynamically via
> > ops->{add,remove}_device().
> 
> > diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> 
> > +/*
> > + * ASID[0] for the system default
> > + * ASID[1] for PPCS, which has SDMMC
> 
> I have no idea what PPCS is. The patch description for 21/22 implies
> much more than SDMMC is "in PPCS"...

"PPCS" is all AHB bus children/(client).

> > + * ASID[2][3].. open for drivers, first come, first served.
> > + */
> > +enum {
> > +	SYSTEM_DEFAULT,
> > +	SYSTEM_PROTECTED,
> > +};
> 
> Why hard-code this mapping? Can't devices be assigned to ASIDs based on
> a DT property? I assume there's nothing in the SMMU HW that requires
> specific ASIDs to be used?

Right. Where should those policy be passed, board DT files?

> I don't see anything in this series which implements the "open for
> drivers" part of the description for ASID 2/3/...

I expect that some smart HW(host1x) will use AS[2/3] for their smarter usage.