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 <asm/cacheflush.h>
  23 #include <mach/omap-wakeupgen.h>
  24
  25 #include "common.h"
  26
  27 #include "powerdomain.h"
  28
  29 int platform_cpu_kill(unsigned int cpu)
  30 {
  31         return 1;
  32 }
  33
  34 /*
  35  * platform-specific code to shutdown a CPU
  36  * Called with IRQs disabled
  37  */
  38 void __ref platform_cpu_die(unsigned int cpu)
  39 {
  40         unsigned int boot_cpu = 0;
  41         void __iomem *base = omap_get_wakeupgen_base();
  42
  43         flush_cache_all();
  44         dsb();
  45
  46         /*
  47          * we're ready for shutdown now, so do it
  48          */
  49         if (omap_secure_apis_support()) {
  50                 if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0)
  51                         pr_err("Secure clear status failed\n");
  52         } else {
  53                 __raw_writel(0, base + OMAP_AUX_CORE_BOOT_0);
  54         }
  55
  56
  57         for (;;) {
  58                 /*
  59                  * Enter into low power state
  60                  */
  61                 omap4_hotplug_cpu(cpu, PWRDM_POWER_OFF);
  62
  63                 if (omap_secure_apis_support())
  64                         boot_cpu = omap_read_auxcoreboot0();
  65                 else
  66                         boot_cpu =
  67                                 __raw_readl(base + OMAP_AUX_CORE_BOOT_0) >> 5;
  68
  69                 if (boot_cpu == smp_processor_id()) {
  70                         /*
  71                          * OK, proper wakeup, we're done
  72                          */
  73                         break;
  74                 }
  75                 pr_debug("CPU%u: spurious wakeup call\n", cpu);
  76         }
  77 }
  78
  79 int platform_cpu_disable(unsigned int cpu)
  80 {
  81         /*
  82          * we don't allow CPU 0 to be shutdown (it is still too special
  83          * e.g. clock tick interrupts)
  84          */
  85         return cpu == 0 ? -EPERM : 0;
  86 }