linux-kernel - Re: [PATCH v3 5/6] soc: apple: Add RTKit IPC library

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Message-Id: <c4a9d56e-571b-4ec4-8833-c1e438666264@www.fastmail.com>
Date:   Wed, 27 Apr 2022 17:31:06 +0200
From:   "Sven Peter" <sven@...npeter.dev>
To:     "Arnd Bergmann" <arnd@...db.de>
Cc:     "Hector Martin" <marcan@...can.st>,
        "Alyssa Rosenzweig" <alyssa@...enzweig.io>,
        "Rob Herring" <robh+dt@...nel.org>,
        "Krzysztof Kozlowski" <krzk+dt@...nel.org>,
        "Keith Busch" <kbusch@...nel.org>, "axboe@...com" <axboe@...com>,
        "hch@....de" <hch@....de>, "sagi@...mberg.me" <sagi@...mberg.me>,
        "Marc Zyngier" <maz@...nel.org>, "Janne Grunau" <j@...nau.net>,
        DTML <devicetree@...r.kernel.org>,
        "Linux ARM" <linux-arm-kernel@...ts.infradead.org>,
        "Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
        linux-nvme@...ts.infradead.org
Subject: Re: [PATCH v3 5/6] soc: apple: Add RTKit IPC library



On Tue, Apr 26, 2022, at 23:01, Arnd Bergmann wrote:
> On Tue, Apr 26, 2022 at 10:15 PM Sven Peter <sven@...npeter.dev> wrote:
>>
>> Apple SoCs such as the M1 come with multiple embedded co-processors
>> running proprietary firmware. Communication with those is established
>> over a simple mailbox using the RTKit IPC protocol.
>>
>> This cannot be implement inside the mailbox subsystem since on top
>> of communication over channels we also need support for starting,
>> hibernating and resetting these co-processors. We also need to
>> handle shared memory allocations differently depending on the
>> co-processor and don't want to split that across multiple drivers.
>>
>> Signed-off-by: Sven Peter <sven@...npeter.dev>
>
> Reviewed-by: Arnd Bergmann <arnd@...db.de>
>

thanks!

>> +bool apple_rtkit_is_running(struct apple_rtkit *rtk)
>> +{
>> +       if (rtk->crashed)
>> +               return false;
>> +       if ((rtk->iop_power_state & 0xff) != APPLE_RTKIT_PWR_STATE_ON)
>> +               return false;
>> +       if ((rtk->ap_power_state & 0xff) != APPLE_RTKIT_PWR_STATE_ON)
>> +               return false;
>> +       return true;
>> +}
>> +EXPORT_SYMBOL_GPL(apple_rtkit_is_running);
>> +
>> +bool apple_rtkit_is_crashed(struct apple_rtkit *rtk)
>> +{
>> +       return rtk->crashed;
>> +}
>> +EXPORT_SYMBOL_GPL(apple_rtkit_is_crashed);
>
> I noticed that you use EXPORT_SYMBOL_GPL() here, but a more permissive
> EXPORT_SYMBOL() in the SART driver. Is that intentional?

No idea why I used both but it wasn't intentional. I'll change all exports
to EXPORT_SYMBOL_GPL.

>
>> +
>> +#if IS_ENABLED(CONFIG_APPLE_RTKIT)
>> +
>
> Same comment about the #if as for the SART driver: I'd prefer it without the
> conditional compilation.

Ok, will remove those #ifs as well.


Sven