Message-ID: <35dc0b00-0de4-f1b4-8d43-7efd181e7dbf@gmail.com>
Date:   Mon, 27 Feb 2023 10:38:51 -0800
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Subject: Re: [PATCH] soc: bcm: brcmstb: Remove bare-metal ARM suspend/resume
 code
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To:     "Guilherme G. Piccoli" <gpiccoli@igalia.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        linux-arm-kernel@vger.kernel.org
Cc:     drv@mailo.com, ssengar@microsoft.com,
        kumarpraveen@linux.microsoft.com, christophe.jaillet@wanadoo.fr,
        Broadcom internal kernel review list 
        <bcm-kernel-feedback-list@broadcom.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
        Arnd Bergmann <arnd@arndb.de>,
        Miaoqian Lin <linmq006@gmail.com>, Liang He <windhl@126.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Julia Lawall <Julia.Lawall@inria.fr>,
        open list <linux-kernel@vger.kernel.org>,
        "moderated list:BROADCOM BCM7XXX ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>
References: <20230224215249.239405-1-f.fainelli@gmail.com>
 <421678cb-6ec0-903c-a84b-c833f013815d@igalia.com>
From:   Florian Fainelli <f.fainelli@gmail.com>
In-Reply-To: <421678cb-6ec0-903c-a84b-c833f013815d@igalia.com>
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On 2/27/2023 10:36 AM, Guilherme G. Piccoli wrote:
> 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@gmail.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?

This is a bit of long story, but no, it is not necessary.
-- 
Florian