Re: [PATCH AUTOSEL 5.5 219/542] ARM: OMAP2+: use separate IOMMU pdata to fix DRA7 IPU1 boot

[Sasha Levin]

On Fri, Feb 14, 2020 at 12:34:58PM -0600, Suman Anna wrote:
> Hi Sasha,
>
> On 2/14/20 9:43 AM, Sasha Levin wrote:
> > From: Suman Anna <s-anna@xxxxxx>
> >
> > [ Upstream commit 4601832f40501efc3c2fd264a5a69bd1ac17d520 ]
> >
> > The IPU1 MMU has been using common IOMMU pdata quirks defined and
> > used by all IPU IOMMU devices on OMAP4 and beyond. Separate out the
> > pdata for IPU1 MMU with the additional .set_pwrdm_constraint ops
> > plugged in, so that the IPU1 power domain can be restricted to ON
> > state during the boot and active period of the IPU1 remote processor.
> > This eliminates the pre-conditions for the IPU1 boot issue as
> > described in commit afe518400bdb ("iommu/omap: fix boot issue on
> > remoteprocs with AMMU/Unicache").
> >
> > NOTE:
> > 1. RET is not a valid target power domain state on DRA7 platforms,
> >    and IPU power domain is normally programmed for OFF. The IPU1
> >    still fails to boot though, and an unclearable l3_noc error is
> >    thrown currently on 4.14 kernel without this fix. This behavior
> >    is slightly different from previous 4.9 LTS kernel.
> > 2. The fix is currently applied only to IPU1 on DRA7xx SoC, as the
> >    other affected processors on OMAP4/OMAP5/DRA7 are in domains
> >    that are not entering RET. IPU2 on DRA7 is in CORE power domain
> >    which is only programmed for ON power state. The fix can be easily
> >    scaled if these domains do hit RET in the future.
> > 3. The issue was not seen on current DRA7 platforms if any of the
> >    DSP remote processors were booted and using one of the GPTimers
> >    5, 6, 7 or 8 on previous 4.9 LTS kernel. This was due to the
> >    errata fix for i874 implemented in commit 1cbabcb9807e ("ARM:
> >    DRA7: clockdomain: Implement timer workaround for errata i874")
> >    which keeps the IPU1 power domain from entering RET when the
> >    timers are active. But the timer workaround did not make any
> >    difference on 4.14 kernel, and an l3_noc error was seen still
> >    without this fix.
> >
> > Signed-off-by: Suman Anna <s-anna@xxxxxx>
> > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
>
> And drop this one as well, since mainline doesn't yet boot
> the processors, so this is not needed for stable queue.

Now dropped, thank you.

--
Thanks,
Sasha