arch/arm/mach-prima2/hotplug.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * CPU hotplug support for CSR Marco dual-core SMP SoCs
   4  *
   5  * Copyright (c) 2012 Cambridge Silicon Radio Limited, a CSR plc group company.
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/errno.h>
  10 #include <linux/smp.h>
  11
  12 #include <asm/smp_plat.h>
  13 #include "common.h"
  14
  15 static inline void platform_do_lowpower(unsigned int cpu)
  16 {
  17         /* we put the platform to just WFI */
  18         for (;;) {
  19                 __asm__ __volatile__("dsb\n\t" "wfi\n\t"
  20                         : : : "memory");
  21                 if (prima2_pen_release == cpu_logical_map(cpu)) {
  22                         /*
  23                          * OK, proper wakeup, we're done
  24                          */
  25                         break;
  26                 }
  27         }
  28 }
  29
  30 /*
  31  * platform-specific code to shutdown a CPU
  32  *
  33  * Called with IRQs disabled
  34  */
  35 void sirfsoc_cpu_die(unsigned int cpu)
  36 {
  37         platform_do_lowpower(cpu);
  38 }