arch/arm/mach-omap2/omap-hotplug.c

   1 /*
   2  * OMAP4 SMP cpu-hotplug support
   3  *
   4  * Copyright (C) 2010 Texas Instruments, Inc.
   5  * Author:
   6  *      Santosh Shilimkar <santosh.shilimkar@ti.com>
   7  *
   8  * Platform file needed for the OMAP4 SMP. This file is based on arm
   9  * realview smp platform.
  10  * Copyright (c) 2002 ARM Limited.
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/errno.h>
  19 #include <linux/smp.h>
  20
  21 #include <asm/cacheflush.h>
  22
  23 #include "common.h"
  24
  25 #include "powerdomain.h"
  26
  27 int platform_cpu_kill(unsigned int cpu)
  28 {
  29         return 1;
  30 }
  31
  32 /*
  33  * platform-specific code to shutdown a CPU
  34  * Called with IRQs disabled
  35  */
  36 void __ref platform_cpu_die(unsigned int cpu)
  37 {
  38         unsigned int this_cpu;
  39
  40         flush_cache_all();
  41         dsb();
  42
  43         /*
  44          * we're ready for shutdown now, so do it
  45          */
  46         if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0)
  47                 pr_err("Secure clear status failed\n");
  48
  49         for (;;) {
  50                 /*
  51                  * Enter into low power state
  52                  */
  53                 omap4_hotplug_cpu(cpu, PWRDM_POWER_OFF);
  54                 this_cpu = smp_processor_id();
  55                 if (omap_read_auxcoreboot0() == this_cpu) {
  56                         /*
  57                          * OK, proper wakeup, we're done
  58                          */
  59                         break;
  60                 }
  61                 pr_debug("CPU%u: spurious wakeup call\n", cpu);
  62         }
  63 }
  64
  65 int platform_cpu_disable(unsigned int cpu)
  66 {
  67         /*
  68          * we don't allow CPU 0 to be shutdown (it is still too special
  69          * e.g. clock tick interrupts)
  70          */
  71         return cpu == 0 ? -EPERM : 0;
  72 }