linux-kernel - Re: [PATCH] soc: bcm: brcmstb: Remove bare-metal ARM suspend/resume code

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Message-ID: <421678cb-6ec0-903c-a84b-c833f013815d@igalia.com>
Date:   Mon, 27 Feb 2023 15:36:05 -0300
From:   "Guilherme G. Piccoli" <gpiccoli@...lia.com>
To:     Florian Fainelli <f.fainelli@...il.com>,
        linux-arm-kernel@...r.kernel.org
Cc:     drv@...lo.com, ssengar@...rosoft.com,
        kumarpraveen@...ux.microsoft.com, christophe.jaillet@...adoo.fr,
        Broadcom internal kernel review list 
        <bcm-kernel-feedback-list@...adcom.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        Miaoqian Lin <linmq006@...il.com>, Liang He <windhl@....com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Julia Lawall <Julia.Lawall@...ia.fr>,
        open list <linux-kernel@...r.kernel.org>,
        "moderated list:BROADCOM BCM7XXX ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] soc: bcm: brcmstb: Remove bare-metal ARM suspend/resume
 code

On 24/02/2023 18:52, Florian Fainelli wrote:
> Since 2018 these platforms have supported entry via the ARM Trusted
> Firmware using the standard PSCI SYSTEM_SUSPEND function calls. Remove
> this legacy code.
> 
> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
> [...]
> -/*
> - * The AON is a small domain in the SoC that can retain its state across
> - * various system wide sleep states and specific reset conditions; the
> - * AON DATA RAM is a small RAM of a few words (< 1KB) which can store
> - * persistent information across such events.
> - *
> - * The purpose of the below panic notifier is to help with notifying
> - * the bootloader that a panic occurred and so that it should try its
> - * best to preserve the DRAM contents holding that buffer for recovery
> - * by the kernel as opposed to wiping out DRAM clean again.
> - *
> - * Reference: comment from Florian Fainelli, at
> - * https://lore.kernel.org/lkml/781cafb0-8d06-8b56-907a-5175c2da196a@gmail.com
> - */
> -static int brcmstb_pm_panic_notify(struct notifier_block *nb,
> -		unsigned long action, void *data)
> -{
> -	writel_relaxed(BRCMSTB_PANIC_MAGIC, ctrl.aon_sram + AON_REG_PANIC);
> -
> -	return NOTIFY_DONE;
> [...]

Hi Florian, thanks for the clean-up!

I'm curious with the above panic notifier - is it not necessary when
PSCI is used?

Cheers,


Guilherme