Re: [PATCH v2] ARM: npcm: Add CPU hotplug callbacks for kexec support

[William Kennington]

On Thu, Nov 2, 2023 at 3:10 AM William A. Kennington III
<william@xxxxxxxxxxxxxxx> wrote:
>
> From: Brian Ma <chma0@xxxxxxxxxxx>
>
> Add callbacks required for kexec to function. The NPCM7xx does
> not expose controls for powering down CPU cores, so just wait in idle
> loop.
>
> Signed-off-by: Brian Ma <chma0@xxxxxxxxxxx>
> Signed-off-by: William A. Kennington III <william@xxxxxxxxxxxxxxx>
> ---
>  arch/arm/mach-npcm/platsmp.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
>
> diff --git a/arch/arm/mach-npcm/platsmp.c b/arch/arm/mach-npcm/platsmp.c
> index 41891d3aa124..6cc7b5894f08 100644
> --- a/arch/arm/mach-npcm/platsmp.c
> +++ b/arch/arm/mach-npcm/platsmp.c
> @@ -69,10 +69,27 @@ static void __init npcm7xx_smp_prepare_cpus(unsigned int max_cpus)
>
>         iounmap(scu_base);
>  }
> +#ifdef CONFIG_HOTPLUG_CPU
> +static void npcm7xx_cpu_die(unsigned int cpu)
> +{
> +       while (1)
> +               cpu_do_idle();
> +}
> +
> +static int npcm7xx_cpu_kill(unsigned int l_cpu)
> +{
> +       return 1;
> +}
> +#endif
> +
>
>  static struct smp_operations npcm7xx_smp_ops __initdata = {
>         .smp_prepare_cpus = npcm7xx_smp_prepare_cpus,
>         .smp_boot_secondary = npcm7xx_smp_boot_secondary,
> +#ifdef CONFIG_HOTPLUG_CPU
> +       .cpu_die                        = npcm7xx_cpu_die,
> +       .cpu_kill                       = npcm7xx_cpu_kill,
> +#endif
>  };
>
>  CPU_METHOD_OF_DECLARE(npcm7xx_smp, "nuvoton,npcm750-smp", &npcm7xx_smp_ops);
> --
> 2.42.0.820.g83a721a137-goog
>'

Mind taking another look? This should be updated accordingly.