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/io.h>
  21
  22 #include "omap-wakeupgen.h"
  23 #include "common.h"
  24 #include "powerdomain.h"
  25
  26 /*
  27  * platform-specific code to shutdown a CPU
  28  * Called with IRQs disabled
  29  */
  30 void omap4_cpu_die(unsigned int cpu)
  31 {
  32         unsigned int boot_cpu = 0;
  33         void __iomem *base = omap_get_wakeupgen_base();
  34
  35         /*
  36          * we're ready for shutdown now, so do it
  37          */
  38         if (omap_secure_apis_support()) {
  39                 if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0)
  40                         pr_err("Secure clear status failed\n");
  41         } else {
  42                 writel_relaxed(0, base + OMAP_AUX_CORE_BOOT_0);
  43         }
  44
  45
  46         for (;;) {
  47                 /*
  48                  * Enter into low power state
  49                  */
  50                 omap4_hotplug_cpu(cpu, PWRDM_POWER_OFF);
  51
  52                 if (omap_secure_apis_support())
  53                         boot_cpu = omap_read_auxcoreboot0();
  54                 else
  55                         boot_cpu =
  56                                 readl_relaxed(base + OMAP_AUX_CORE_BOOT_0) >> 5;
  57
  58                 if (boot_cpu == smp_processor_id()) {
  59                         /*
  60                          * OK, proper wakeup, we're done
  61                          */
  62                         break;
  63                 }
  64                 pr_debug("CPU%u: spurious wakeup call\n", cpu);
  65         }
  66 }