[PATCH linux-next tag: next-20210322] ARM: aspeed: Add CPU hotplug callbacks for kexec support

[Bruce Mitchell]

On 3/22/2021 08:57, Bruce Mitchell wrote:
> These callbacks are required for kexec to function. The AST2600 does not
> expose any controls for powering down it's CPU cores, so we borrow the
> approach taken from socfpga and wait in the idle loop.
> 
> Author: Joel Stanley <joel at jms.id.au>
> 
> Signed-off-by: Bruce Mitchell <bruce.mitchell at linux.vnet.ibm.com>
> ---
>   arch/arm/mach-aspeed/platsmp.c | 20 ++++++++++++++++++++
>   1 file changed, 20 insertions(+)
> 
> diff --git a/arch/arm/mach-aspeed/platsmp.c b/arch/arm/mach-aspeed/platsmp.c
> index 2324becf7991..1ae3ff5a9701 100644
> --- a/arch/arm/mach-aspeed/platsmp.c
> +++ b/arch/arm/mach-aspeed/platsmp.c
> @@ -7,6 +7,8 @@
>   #include <linux/of.h>
>   #include <linux/smp.h>
> 
> +#include <asm/proc-fns.h>
> +
>   #define BOOT_ADDR	0x00
>   #define BOOT_SIG	0x04
> 
> @@ -53,9 +55,27 @@ static void __init aspeed_g6_smp_prepare_cpus(unsigned int max_cpus)
>   	iounmap(base);
>   }
> 
> +#ifdef CONFIG_HOTPLUG_CPU
> +static void aspeed_g6_cpu_die(unsigned int cpu)
> +{
> +        /* Do WFI. If we wake up early, go back into WFI */
> +        while (1)
> +                cpu_do_idle();
> +}
> +
> +static int aspeed_g6_cpu_kill(unsigned int cpu)
> +{
> +        return 1;
> +}
> +#endif
> +
>   static const struct smp_operations aspeed_smp_ops __initconst = {
>   	.smp_prepare_cpus	= aspeed_g6_smp_prepare_cpus,
>   	.smp_boot_secondary	= aspeed_g6_boot_secondary,
> +#ifdef CONFIG_HOTPLUG_CPU
> +	.cpu_die		= aspeed_g6_cpu_die,
> +	.cpu_kill		= aspeed_g6_cpu_kill,
> +#endif
>   };
> 
>   CPU_METHOD_OF_DECLARE(aspeed_smp, "aspeed,ast2600-smp", &aspeed_smp_ops);
> 

Adding Andrew Jeffery and Eddie James to the CC list.

-- 
Bruce