Re: [Linaro-acpi] [PATCH v3 3/3] ARM: Check if a CPU has gone offline

On Thu, Mar 27, 2014 at 4:23 PM, Ashwin Chaugule ashwin.chaugule@linaro.org wrote:

PSCIv0.2 adds a new function called AFFINITY_INFO, which can be used to query if a specified CPU has actually gone offline. Calling this function via cpu_kill ensures that a CPU has quiesced after a call to cpu_die.

Signed-off-by: Ashwin Chaugule ashwin.chaugule@linaro.org

One minor nit, but otherwise:

Reviewed-by: Rob Herring robh@kernel.org

---

arch/arm/kernel/psci_smp.c | 21 +++++++++++++++++++++ include/uapi/linux/psci.h | 5 +++++ 2 files changed, 26 insertions(+)

diff --git a/arch/arm/kernel/psci_smp.c b/arch/arm/kernel/psci_smp.c index 570a48c..4c1adf9 100644 --- a/arch/arm/kernel/psci_smp.c +++ b/arch/arm/kernel/psci_smp.c @@ -16,6 +16,7 @@ #include <linux/init.h> #include <linux/smp.h> #include <linux/of.h> +#include <uapi/linux/psci.h>

#include <asm/psci.h> #include <asm/smp_plat.h> @@ -66,6 +67,25 @@ void __ref psci_cpu_die(unsigned int cpu) /* We should never return */ panic("psci: cpu %d failed to shutdown\n", cpu); }

+int __ref psci_cpu_kill(unsigned int cpu) +{

•   int err;
  

•   if (!psci_ops.affinity_info)
  

•           return 1;
  

•   err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
  

•   if (err != PSCI_AFFINITY_INFO_RET_OFF) {
  

•           pr_err("psci: Cannot kill CPU:%d, psci ret val: %d\n",
  

•                           cpu, err);
  

•           /* Make platform_cpu_kill() fail. */
  

•           return 0;
  

•   }
  

•   return err;
  

I think this should just be "return 1;" PSCI_AFFINITY_INFO_RET_OFF happens to match, but it's really different meanings.

+}

#endif

bool __init psci_smp_available(void) @@ -78,5 +98,6 @@ struct smp_operations __initdata psci_smp_ops = { .smp_boot_secondary = psci_boot_secondary, #ifdef CONFIG_HOTPLUG_CPU .cpu_die = psci_cpu_die,

•   .cpu_kill               = psci_cpu_kill,
  

#endif }; diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h index c523051..2c177f5 100644 --- a/include/uapi/linux/psci.h +++ b/include/uapi/linux/psci.h @@ -37,4 +37,9 @@ #define PSCI_RET_EINVAL -2 #define PSCI_RET_EPERM -3

+/* Return values from the PSCI_ID_AFFINITY_INFO Function. */ +#define PSCI_AFFINITY_INFO_RET_ON 0 +#define PSCI_AFFINITY_INFO_RET_OFF 1 +#define PSCI_AFFINITY_INFO_RET_ON_PENDING 2

#endif /* _UAPI_LINUX_PSCI_H */

1.8.3.2