linux-kernel - Re: [PATCH] ARM: dt: check MPIDR on MP devices built without SMP

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Message-ID: <e2487ea8-67d0-b850-af63-683dff498275@gmx.net>
Date:   Thu, 3 Oct 2019 19:28:33 +0200
From:   Stefan Wahren <wahrenst@....net>
To:     Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        linux-kernel@...r.kernel.org
Cc:     "kernelci.org bot" <bot@...nelci.org>,
        Russell King <linux@...linux.org.uk>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] ARM: dt: check MPIDR on MP devices built without SMP

Am 02.10.19 um 13:45 schrieb Nicolas Saenz Julienne:
> Currently, in arm_dt_init_cpu_maps(), the hwid of the boot CPU is read
> from MPIDR on SMP devices and set to 0 for non SMP. This value is then
> matched with the DT cpu nodes' reg property in order to find the boot
> CPU in DT.
>
> On MP devices build without SMP the cpu DT node contains the expected
> MPIDR yet the hwid is set to 0. With this the function fails to match
> the cpus and uses the default CPU logical map. Making it impossible to
> get the CPU's DT node further down the line. This causes issues with
> cpufreq-dt, as it triggers warnings when not finding a suitable DT node
> on CPU0.
>
> Change the way we choose whether to get MPIDR or not. Instead of
> depending on SMP check the number of CPUs defined in DT. Anything > 1
> means MPIDR will be available.
>
> This was seen on a Raspberry Pi 2 build with bcm2835_defconfig.
>
> Reported-by: "kernelci.org bot" <bot@...nelci.org>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@...e.de>
> ---

Tested-by: Stefan Wahren <wahrenst@....net>

Thanks