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Message-ID: <CANgGJDpJX+ji1U3SN+2Q21FyckFQhmwb-Z2Qcx4-+GQ2ijmfCg@mail.gmail.com>
Date: Fri, 9 Feb 2024 14:52:20 +0000
From: Alexey Klimov <alexey.klimov@...aro.org>
To: Peter Griffin <peter.griffin@...aro.org>
Cc: arnd@...db.de, krzysztof.kozlowski@...aro.org, linux@...ck-us.net,
wim@...ux-watchdog.org, alim.akhtar@...sung.com, jaewon02.kim@...sung.com,
semen.protsenko@...aro.org, kernel-team@...roid.com, tudor.ambarus@...aro.org,
andre.draszik@...aro.org, saravanak@...gle.com, willmcvicker@...gle.com,
linux-fsd@...la.com, linux-watchdog@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH v4 1/2] soc: samsung: exynos-pmu: Add regmap support for
SoCs that protect PMU regs
On Thu, 8 Feb 2024 at 16:21, Peter Griffin <peter.griffin@...aro.org> wrote:
>
> Some Exynos based SoCs like Tensor gs101 protect the PMU registers for
> security hardening reasons so that they are only write accessible in el3
> via an SMC call.
>
> As most Exynos drivers that need to write PMU registers currently obtain a
> regmap via syscon (phys, pinctrl, watchdog). Support for the above usecase
> is implemented in this driver using a custom regmap similar to syscon to
> handle the SMC call. Platforms that don't secure PMU registers, get a mmio
> regmap like before. As regmaps abstract out the underlying register access
> changes to the leaf drivers are minimal.
>
> A new API exynos_get_pmu_regmap_by_phandle() is provided for leaf drivers
> that currently use syscon_regmap_lookup_by_phandle(). This also handles
> deferred probing.
>
> Signed-off-by: Peter Griffin <peter.griffin@...aro.org>
Tested-by: Alexey Klimov <alexey.klimov@...aro.org>
Apparently it seems tested-by should be provided for both patches. This was
also tested on odroid xu3 and I also have WIP code that depends on this
SMC-based regmap. No issues are observed and behaves as expected.
> ---
> Changes since v3:
> - Fix PMUALIVE_MASK
> - Add TENSOR_ prefix
> - clear SET_BITS bits on each loop iteration
> - change set_bit to set_bits in func name
> - Fix some alignment
> - Add missing return on dev_err_probe
> - Reduce indentation in loop
I no longer see the compilation warning related to struct device_node declared
inside parameter list with v4, I guess one line change addition in exynos-pmu.h
does the job.
Thank you!
BR,
Alexey
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