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 #include <mach/omap4-common.h>
  23
  24 int platform_cpu_kill(unsigned int cpu)
  25 {
  26         return 1;
  27 }
  28
  29 /*
  30  * platform-specific code to shutdown a CPU
  31  * Called with IRQs disabled
  32  */
  33 void platform_cpu_die(unsigned int cpu)
  34 {
  35         flush_cache_all();
  36         dsb();
  37
  38         /*
  39          * we're ready for shutdown now, so do it
  40          */
  41         if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0)
  42                 printk(KERN_CRIT "Secure clear status failed\n");
  43
  44         for (;;) {
  45                 /*
  46                  * Execute WFI
  47                  */
  48                 do_wfi();
  49
  50                 if (omap_read_auxcoreboot0() == cpu) {
  51                         /*
  52                          * OK, proper wakeup, we're done
  53                          */
  54                         break;
  55                 }
  56                 pr_debug("CPU%u: spurious wakeup call\n", cpu);
  57         }
  58 }
  59
  60 int platform_cpu_disable(unsigned int cpu)
  61 {
  62         /*
  63          * we don't allow CPU 0 to be shutdown (it is still too special
  64          * e.g. clock tick interrupts)
  65          */
  66         return cpu == 0 ? -EPERM : 0;
  67 }