From: Mark Rutland <mark.rutland@arm.com> To: Florian Fainelli <f.fainelli@gmail.com> Cc: linux-arm-kernel@lists.infradead.org, "maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE" <bcm-kernel-feedback-list@broadcom.com>, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>, open list <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 0/4] Broadcom STB PM PSCI extensions Date: Thu, 3 Feb 2022 10:47:13 +0000 [thread overview] Message-ID: <YfuysSBnZbnMF4OC@FVFF77S0Q05N> (raw) In-Reply-To: <20220122035421.4086618-1-f.fainelli@gmail.com> 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 >
WARNING: multiple messages have this Message-ID (diff)
From: Mark Rutland <mark.rutland@arm.com> To: Florian Fainelli <f.fainelli@gmail.com> Cc: linux-arm-kernel@lists.infradead.org, "maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE" <bcm-kernel-feedback-list@broadcom.com>, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>, open list <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 0/4] Broadcom STB PM PSCI extensions Date: Thu, 3 Feb 2022 10:47:13 +0000 [thread overview] Message-ID: <YfuysSBnZbnMF4OC@FVFF77S0Q05N> (raw) In-Reply-To: <20220122035421.4086618-1-f.fainelli@gmail.com> 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 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-02-03 10:47 UTC|newest] Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-22 3:54 [PATCH 0/4] Broadcom STB PM PSCI extensions Florian Fainelli 2022-01-22 3:54 ` Florian Fainelli 2022-01-22 3:54 ` [PATCH 1/4] firmware: psci: Export a couple of suspend symbols Florian Fainelli 2022-01-22 3:54 ` Florian Fainelli 2022-01-22 12:22 ` kernel test robot 2022-01-22 12:22 ` kernel test robot 2022-01-22 3:54 ` [PATCH 2/4] soc: bcm: brcmstb: Make legacy PM code depend on !ARM_PSCI_FW Florian Fainelli 2022-01-22 3:54 ` Florian Fainelli 2022-01-22 3:54 ` [PATCH 3/4] soc: bcm: brcmstb: Added support for PSCI system suspend operations Florian Fainelli 2022-01-22 3:54 ` Florian Fainelli 2022-01-22 6:09 ` kernel test robot 2022-01-22 6:09 ` kernel test robot 2022-01-22 7:10 ` kernel test robot 2022-01-22 7:10 ` kernel test robot 2022-02-03 12:09 ` Mark Rutland 2022-02-03 12:09 ` Mark Rutland 2022-02-03 18:45 ` Florian Fainelli 2022-02-03 18:45 ` Florian Fainelli 2022-01-22 3:54 ` [PATCH 4/4] Documentation: ABI: Document Broadcom STB PSCI firmware files Florian Fainelli 2022-01-22 3:54 ` Florian Fainelli 2022-01-27 3:55 ` [PATCH 0/4] Broadcom STB PM PSCI extensions Florian Fainelli 2022-01-27 3:55 ` Florian Fainelli 2022-02-03 10:47 ` Mark Rutland [this message] 2022-02-03 10:47 ` Mark Rutland 2022-02-03 18:32 ` Florian Fainelli 2022-02-03 18:32 ` Florian Fainelli 2022-02-03 11:14 ` Sudeep Holla 2022-02-03 11:14 ` Sudeep Holla 2022-02-03 17:36 ` Florian Fainelli 2022-02-03 17:36 ` Florian Fainelli 2022-02-03 18:52 ` Sudeep Holla 2022-02-03 18:52 ` Sudeep Holla 2022-02-03 19:33 ` Florian Fainelli 2022-02-03 19:33 ` Florian Fainelli 2022-02-07 16:27 ` Sudeep Holla 2022-02-07 16:27 ` Sudeep Holla 2022-02-14 18:12 ` Florian Fainelli 2022-02-14 18:12 ` Florian Fainelli
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