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SubjectRe: [PATCH] keystone: psci: adds cpu_die implementation
Hi,

On Thu, Jun 25, 2015 at 03:02:50PM +0100, Vitaly Andrianov wrote:
> This commit add cpu_die implementation using psci api

I don't understand. If you have a PSCI implementation, it should be
sufficient to have a PSCI node (and enable-method) in your DT, and the
generic code will be used. Nothing should be required in your board
code.

You should also use CPU_ON to bring secondaries online rather than
mixing up PSCI and platform-specific mechanisms.

>
> Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
> ---
> arch/arm/mach-keystone/platsmp.c | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/arch/arm/mach-keystone/platsmp.c b/arch/arm/mach-keystone/platsmp.c
> index 5f46a7c..2c40cc0 100644
> --- a/arch/arm/mach-keystone/platsmp.c
> +++ b/arch/arm/mach-keystone/platsmp.c
> @@ -20,6 +20,7 @@
> #include <asm/prom.h>
> #include <asm/tlbflush.h>
> #include <asm/pgtable.h>
> +#include <asm/psci.h>
>
> #include "keystone.h"
>
> @@ -51,7 +52,38 @@ static inline void __cpuinit keystone_smp_secondary_initmem(unsigned int cpu)
> {}
> #endif
>
> +
> +#ifdef CONFIG_HOTPLUG_CPU
> +static void keystone_cpu_die(unsigned int cpu)
> +{
> +#ifdef CONFIG_ARM_PSCI
> + struct psci_power_state pwr_state = {0, 0, 0};
> +
> + pr_info("keystone_cpu_die(%d) from %d using PSCI\n", cpu,
> + smp_processor_id());
> +
> + if (psci_ops.cpu_off)
> + psci_ops.cpu_off(pwr_state);
> +#else
> + /*
> + * We may want to add here a direct smc call to monitor
> + * if the kernel doesn't support PSCI API
> + */
> +#endif

You should determine this from your DT. Your FW/bootloader can patch in
the relevant nodes and properties when support is present, so the
presence of such nodes should guarantee that PSCI is available.

> +
> + /*
> + * we shouldn't come here. But in case something went
> + * wrong the code below prevents kernel from crush
> + */
> + while (1)
> + cpu_do_idle();

This will make kexec appear to work, yet it won't.

Thanks,
Mark.

> +}
> +#endif
> +
> struct smp_operations keystone_smp_ops __initdata = {
> .smp_boot_secondary = keystone_smp_boot_secondary,
> .smp_secondary_init = keystone_smp_secondary_initmem,
> +#ifdef CONFIG_HOTPLUG_CPU
> + .cpu_die = keystone_cpu_die,
> +#endif
> };
> --
> 1.9.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>


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