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 "omap-wakeupgen.h"
  24
  25 #include "common.h"
  26
  27 #include "powerdomain.h"
  28
  29 /*
  30  * platform-specific code to shutdown a CPU
  31  * Called with IRQs disabled
  32  */
  33 void __ref omap4_cpu_die(unsigned int cpu)
  34 {
  35         unsigned int boot_cpu = 0;
  36         void __iomem *base = omap_get_wakeupgen_base();
  37
  38         flush_cache_all();
  39         dsb();
  40
  41         /*
  42          * we're ready for shutdown now, so do it
  43          */
  44         if (omap_secure_apis_support()) {
  45                 if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0)
  46                         pr_err("Secure clear status failed\n");
  47         } else {
  48                 __raw_writel(0, base + OMAP_AUX_CORE_BOOT_0);
  49         }
  50
  51
  52         for (;;) {
  53                 /*
  54                  * Enter into low power state
  55                  */
  56                 omap4_hotplug_cpu(cpu, PWRDM_POWER_OFF);
  57
  58                 if (omap_secure_apis_support())
  59                         boot_cpu = omap_read_auxcoreboot0();
  60                 else
  61                         boot_cpu =
  62                                 __raw_readl(base + OMAP_AUX_CORE_BOOT_0) >> 5;
  63
  64                 if (boot_cpu == smp_processor_id()) {
  65                         /*
  66                          * OK, proper wakeup, we're done
  67                          */
  68                         break;
  69                 }
  70                 pr_debug("CPU%u: spurious wakeup call\n", cpu);
  71         }
  72 }