linux-kernel - Re: [RFC 0/2] Add workaround for core wake-up on IPI for i.MX8MQ

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Message-ID: <02ed2f06-7873-72a1-5610-961efaca28ac@posteo.de>
Date:   Wed, 30 Oct 2019 08:33:44 +0100
From:   Martin Kepplinger <martink@...teo.de>
To:     Abel Vesa <abelvesa@...il.com>, Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <marc.zyngier@....com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Bai Ping <ping.bai@....com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Leonard Crestez <leonard.crestez@....com>
Cc:     devicetree@...r.kernel.org, Carlo Caione <ccaione@...libre.com>,
        NXP Linux Team <linux-imx@....com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC 0/2] Add workaround for core wake-up on IPI for i.MX8MQ

On 30.10.19 07:11, Martin Kepplinger wrote:
> On 23.06.19 13:47, Martin Kepplinger wrote:
>> On 10.06.19 14:13, Abel Vesa wrote:
>>> This is another alternative for the RFC:
>>> https://lkml.org/lkml/2019/3/27/545
>>>
>>> This new workaround proposal is a little bit more hacky but more contained
>>> since everything is done within the irq-imx-gpcv2 driver.
>>>
>>> Basically, it 'hijacks' the registered gic_raise_softirq __smp_cross_call
>>> handler and registers instead a wrapper which calls in the 'hijacked' 
>>> handler, after that calling into EL3 which will take care of the actual
>>> wake up. This time, instead of expanding the PSCI ABI, we use a new vendor SIP.
>>>
>>> I also have the patches ready for TF-A but I'll hold on to them until I see if
>>> this has a chance of getting in.
>>
> 
> Hi Abel,
> 
> Running this workaround doesn't seem to work anymore on 5.4-rcX. Linux
> doesn't boot, with ATF unchanged (includes your workaround changes). I
> can try to add more details to this...
> 

When I run this change instead:
https://source.puri.sm/Librem5/linux-next/commit/e59807ae0e236512761b751abc84a9b129d7fcda
(again, with the same ATF) Linux 5.4 boots, but simply doesn't load a
cpuidle driver (cpu-sleep; and cpuidle in /sys/devices/system/cpu/cpu0).

Still, since this is starting with 5.4-rcX, my previous questions stay
the same :)

thanks,
                                      martin