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 <asm/hardware/gic.h>
  23
  24 #include <mach/omap4-common.h>
  25 #include <mach/omap-wakeupgen.h>
  26
  27 #include "powerdomain.h"
  28 #include "clockdomain.h"
  29
  30 int platform_cpu_kill(unsigned int cpu)
  31 {
  32         return 1;
  33 }
  34
  35 /*
  36  * platform-specific code to shutdown a CPU
  37  * Called with IRQs disabled
  38  */
  39 void platform_cpu_die(unsigned int cpu)
  40 {
  41         unsigned int this_cpu;
  42         static struct clockdomain *cpu1_clkdm;
  43
  44         if (!cpu1_clkdm)
  45                 cpu1_clkdm = clkdm_lookup("mpu1_clkdm");
  46
  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                 pr_err("Secure clear status failed\n");
  55
  56         for (;;) {
  57                 /*
  58                  * Enter into low power state
  59                  * clear all interrupt wakeup sources
  60                  */
  61                 omap_wakeupgen_irqmask_all(cpu, 1);
  62                 gic_cpu_disable();
  63                 omap4_enter_lowpower(cpu, PWRDM_POWER_OFF);
  64                 this_cpu = hard_smp_processor_id();
  65                 if (omap_read_auxcoreboot0() == this_cpu) {
  66                         /*
  67                          * OK, proper wakeup, we're done
  68                          */
  69                         omap_wakeupgen_irqmask_all(this_cpu, 0);
  70                         gic_cpu_enable();
  71
  72                         /* Restore clockdomain to hardware supervised */
  73                         clkdm_allow_idle(cpu1_clkdm);
  74                         break;
  75                 }
  76                 pr_debug("CPU%u: spurious wakeup call\n", cpu);
  77         }
  78 }
  79
  80 int platform_cpu_disable(unsigned int cpu)
  81 {
  82         /*
  83          * we don't allow CPU 0 to be shutdown (it is still too special
  84          * e.g. clock tick interrupts)
  85          */
  86         return cpu == 0 ? -EPERM : 0;
  87 }