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 #include <linux/completion.h>
  21
  22 #include <asm/cacheflush.h>
  23 #include <mach/omap4-common.h>
  24
  25 static DECLARE_COMPLETION(cpu_killed);
  26
  27 int platform_cpu_kill(unsigned int cpu)
  28 {
  29         return wait_for_completion_timeout(&cpu_killed, 5000);
  30 }
  31
  32 /*
  33  * platform-specific code to shutdown a CPU
  34  * Called with IRQs disabled
  35  */
  36 void platform_cpu_die(unsigned int cpu)
  37 {
  38         unsigned int this_cpu = hard_smp_processor_id();
  39
  40         if (cpu != this_cpu) {
  41                 pr_crit("platform_cpu_die running on %u, should be %u\n",
  42                            this_cpu, cpu);
  43                 BUG();
  44         }
  45         pr_notice("CPU%u: shutdown\n", cpu);
  46         complete(&cpu_killed);
  47         flush_cache_all();
  48         dsb();
  49
  50         /*
  51          * we're ready for shutdown now, so do it
  52          */
  53         if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0)
  54                 printk(KERN_CRIT "Secure clear status failed\n");
  55
  56         for (;;) {
  57                 /*
  58                  * Execute WFI
  59                  */
  60                 do_wfi();
  61
  62                 if (omap_read_auxcoreboot0() == cpu) {
  63                         /*
  64                          * OK, proper wakeup, we're done
  65                          */
  66                         break;
  67                 }
  68                 pr_debug("CPU%u: spurious wakeup call\n", cpu);
  69         }
  70 }
  71
  72 int platform_cpu_disable(unsigned int cpu)
  73 {
  74         /*
  75          * we don't allow CPU 0 to be shutdown (it is still too special
  76          * e.g. clock tick interrupts)
  77          */
  78         return cpu == 0 ? -EPERM : 0;
  79 }