arch/arm/mach-shmobile/platsmp-scu.c

   1 /*
   2  * SMP support for SoCs with SCU covered by mach-shmobile
   3  *
   4  * Copyright (C) 2013  Magnus Damm
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/delay.h>
  11 #include <linux/init.h>
  12 #include <linux/io.h>
  13 #include <linux/smp.h>
  14 #include <asm/cacheflush.h>
  15 #include <asm/smp_plat.h>
  16 #include <asm/smp_scu.h>
  17 #include <mach/common.h>
  18
  19 void __init shmobile_smp_scu_prepare_cpus(unsigned int max_cpus)
  20 {
  21         /* install boot code shared by all CPUs */
  22         shmobile_boot_fn = virt_to_phys(shmobile_smp_boot);
  23         shmobile_boot_arg = MPIDR_HWID_BITMASK;
  24
  25         /* enable SCU and cache coherency on booting CPU */
  26         scu_enable(shmobile_scu_base);
  27         scu_power_mode(shmobile_scu_base, SCU_PM_NORMAL);
  28 }
  29
  30 int shmobile_smp_scu_boot_secondary(unsigned int cpu, struct task_struct *idle)
  31 {
  32         /* For this particular CPU register SCU boot vector */
  33         shmobile_smp_hook(cpu, virt_to_phys(shmobile_boot_scu),
  34                           (unsigned long)shmobile_scu_base);
  35         return 0;
  36 }
  37
  38 #ifdef CONFIG_HOTPLUG_CPU
  39 void shmobile_smp_scu_cpu_die(unsigned int cpu)
  40 {
  41         /* For this particular CPU deregister boot vector */
  42         shmobile_smp_hook(cpu, 0, 0);
  43
  44         dsb();
  45         flush_cache_all();
  46
  47         /* disable cache coherency */
  48         scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);
  49
  50         /* jump to shared mach-shmobile sleep / reset code */
  51         shmobile_smp_sleep();
  52 }
  53
  54 static int shmobile_smp_scu_psr_core_disabled(int cpu)
  55 {
  56         unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);
  57
  58         if ((__raw_readl(shmobile_scu_base + 8) & mask) == mask)
  59                 return 1;
  60
  61         return 0;
  62 }
  63
  64 int shmobile_smp_scu_cpu_kill(unsigned int cpu)
  65 {
  66         int k;
  67
  68         /* this function is running on another CPU than the offline target,
  69          * here we need wait for shutdown code in platform_cpu_die() to
  70          * finish before asking SoC-specific code to power off the CPU core.
  71          */
  72         for (k = 0; k < 1000; k++) {
  73                 if (shmobile_smp_scu_psr_core_disabled(cpu))
  74                         return 1;
  75
  76                 mdelay(1);
  77         }
  78
  79         return 0;
  80 }
  81 #endif