From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33432C433F5 for ; Thu, 3 Feb 2022 10:47:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241811AbiBCKrX (ORCPT ); Thu, 3 Feb 2022 05:47:23 -0500 Received: from foss.arm.com ([217.140.110.172]:38186 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230516AbiBCKrW (ORCPT ); Thu, 3 Feb 2022 05:47:22 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3FD98113E; Thu, 3 Feb 2022 02:47:22 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.89.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 434513F774; Thu, 3 Feb 2022 02:47:21 -0800 (PST) Date: Thu, 3 Feb 2022 10:47:13 +0000 From: Mark Rutland To: Florian Fainelli Cc: linux-arm-kernel@lists.infradead.org, "maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE" , Lorenzo Pieralisi , open list Subject: Re: [PATCH 0/4] Broadcom STB PM PSCI extensions Message-ID: References: <20220122035421.4086618-1-f.fainelli@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220122035421.4086618-1-f.fainelli@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 >