Re: [PATCH V3 0/3] memory: tegra: Restore MC state on system resume

Jon Hunter
2026-05-01T10:29:59Z

On 30/04/2026 10:51, Ashish Mhetre wrote:
> The tegra-mc platform driver does not register any dev_pm_ops, so the
> SoC-specific ->resume() is never invoked (e.g. tegra186_mc_resume) on
> system wake. On Tegra186 and later this means MC client Stream-ID
> override registers are not reprogrammed, and clients behind the ARM
> SMMU fault on the first DMA after resume.
>
> Patch 1 makes the SoC-level ->resume() callback return void, since the
> sole implementation never fails. This simplifies the wrapper added in
> the next patch.
>
> Patch 2 registers a dev_pm_ops on the tegra-mc driver and routes the
> system resume callback into mc->soc->ops->resume() so the existing SID
> restore path runs again on wake.
>
> Patch 3 factors the existing intmask programming out of
> tegra_mc_probe() into a helper and reuses it from the resume path so
> the MC interrupt mask state, which is also lost across SC7, is
> restored on wake too.
>
> Changes in V3:
> - New patch 1 to change the SoC ->resume() callback return type from
> int to void, so the wrapper in patch 2 does not need to deal with
> an err value that is always 0. (Jon Hunter)
> - Patches 2 and 3 simplified accordingly, no other functional change.
>
> Changes in V2:
> - Split the original single patch into two - register the PM ops and
> reprogram the MC interrupt masks on resume.
>
> Ashish Mhetre (3):
> memory: tegra: Make ->resume() callback return void
> memory: tegra: Wire up system sleep PM ops
> memory: tegra: Restore MC interrupt masks on resume
>
> drivers/memory/tegra/mc.c | 37 ++++++++++++++++++++++++++-------
> drivers/memory/tegra/tegra186.c | 4 +---
> include/soc/tegra/mc.h | 2 +-
> 3 files changed, 32 insertions(+), 11 deletions(-)
>

For the series ...

Reviewed-by: Jon Hunter <jonathanh@nvidia.com>

Thanks!
Jon

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