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hotplug.c

/*
 * Copyright (C) STMicroelectronics 2009
 * Copyright (C) ST-Ericsson SA 2010
 *
 * License Terms: GNU General Public License v2
 *    Based on ARM realview platform
 *
 * Author: Sundar Iyer <sundar.iyer@stericsson.com>
 *
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/smp.h>

#include <asm/cacheflush.h>

extern volatile int pen_release;

static inline void platform_do_lowpower(unsigned int cpu)
{
      flush_cache_all();

      /* we put the platform to just WFI */
      for (;;) {
            __asm__ __volatile__("dsb\n\t" "wfi\n\t"
                        : : : "memory");
            if (pen_release == cpu) {
                  /*
                   * OK, proper wakeup, we're done
                   */
                  break;
            }
      }
}

int platform_cpu_kill(unsigned int cpu)
{
      return 1;
}

/*
 * platform-specific code to shutdown a CPU
 *
 * Called with IRQs disabled
 */
void platform_cpu_die(unsigned int cpu)
{
      /* directly enter low power state, skipping secure registers */
      platform_do_lowpower(cpu);
}

int platform_cpu_disable(unsigned int cpu)
{
      /*
       * we don't allow CPU 0 to be shutdown (it is still too special
       * e.g. clock tick interrupts)
       */
      return cpu == 0 ? -EPERM : 0;
}

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