Messages in this thread | | | Date | Thu, 3 Feb 2022 10:47:13 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH 0/4] Broadcom STB PM PSCI extensions |
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On Fri, Jan 21, 2022 at 07:54:17PM -0800, Florian Fainelli wrote: > Hi all,
Hi Florian,
> This patch series contains the Broadcom STB PSCI extensions which adds > some additional functions on top of the existing standard PSCI interface > which is the reason for having the driver implement a custom > suspend_ops.
I *really* don't like the idea of having non-standard PSCI extensions, because it somewhat defeats the point of PSCI being a standard, and opens the door for the zoo of mechanisms we had on 32-bit.
I think this needs a fair amount more explanation and justification.
> These platforms have traditionally supported a mode that is akin to > ACPI's S2 with the CPU in WFI and all of the chip being clock gated > which is entered with "echo standby > /sys/power/state". Additional a > true suspend to DRAM as defined in ACPI by S3 is implemented with "echo > mem > /sys/power/state".
Why isn't a combination of CPU_SUSPEND and SYSTEM_SUSPEND sufficient here?
What specifically *can't* you do with standard PSCI calls?
> These platforms also may have an external Broadcom PMIC chip which can > cause the SoC to be powercycled assuming that we communicate that intent > via a vendor specific PSCI SYSTEM_RESET2. > > Since it is desirable to get any new functionality added to the kernel > to be loadable as a module as part of shipping said products in a Google > Kernel Image (GKI) environment, we need to export a couple of symbols from > drivers/firmware/psci/psci.c.
I really don't want to export the guts of psci.c.
Thanks, Mark.
> Thanks for your feedback. > > Florian Fainelli (4): > firmware: psci: Export a couple of suspend symbols > soc: bcm: brcmstb: Make legacy PM code depend on !ARM_PSCI_FW > soc: bcm: brcmstb: Added support for PSCI system suspend operations > Documentation: ABI: Document Broadcom STB PSCI firmware files > > .../ABI/testing/sysfs-firmware-brcmstb | 16 + > drivers/firmware/psci/psci.c | 9 +- > drivers/soc/bcm/brcmstb/Kconfig | 4 +- > drivers/soc/bcm/brcmstb/pm/Makefile | 3 + > drivers/soc/bcm/brcmstb/pm/pm-psci.c | 315 ++++++++++++++++++ > include/linux/psci.h | 2 + > include/linux/soc/brcmstb/brcmstb-smccc.h | 84 +++++ > 7 files changed, 430 insertions(+), 3 deletions(-) > create mode 100644 Documentation/ABI/testing/sysfs-firmware-brcmstb > create mode 100644 drivers/soc/bcm/brcmstb/pm/pm-psci.c > create mode 100644 include/linux/soc/brcmstb/brcmstb-smccc.h > > -- > 2.25.1 >
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