linux-kernel - Re: [PATCH 0/4] Broadcom STB PM PSCI extensions

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Message-ID: <c7b80842-1e30-8a25-933c-da8658a91287@gmail.com>
Date:   Wed, 26 Jan 2022 19:55:09 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     "maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE" 
        <bcm-kernel-feedback-list@...adcom.com>,
        Mark Rutland <mark.rutland@....com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 0/4] Broadcom STB PM PSCI extensions



On 1/21/2022 7:54 PM, Florian Fainelli wrote:
> Hi all,
> 
> 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.
> 
> 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".
> 
> 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.
> 
> Thanks for your feedback.

I will be sending a v2 addressing the kbuild robot failures reported but 
would prefer to get some feedback first so it can be addressed 
simultaneously. Thanks!

> 
> 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
> 

-- 
Florian