/*
   * SMP support for SoCs with SCU covered by mach-shmobile
   *
   * Copyright (C) 2013  Magnus Damm
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */

  #include <linux/cpu.h>

  #include <linux/delay.h>

  #include <linux/init.h>
  #include <linux/io.h>
  #include <linux/smp.h>

  #include <asm/cacheflush.h>

  #include <asm/smp_plat.h>
  #include <asm/smp_scu.h>

  #include "common.h"

  static int shmobile_smp_scu_notifier_call(struct notifier_block *nfb,
  					  unsigned long action, void *hcpu)
  {
  	unsigned int cpu = (long)hcpu;
  
  	switch (action) {
  	case CPU_UP_PREPARE:
  		/* For this particular CPU register SCU SMP boot vector */
  		shmobile_smp_hook(cpu, virt_to_phys(shmobile_boot_scu),
  				  (unsigned long)shmobile_scu_base);
  		break;
  	};
  
  	return NOTIFY_OK;
  }
  
  static struct notifier_block shmobile_smp_scu_notifier = {
  	.notifier_call = shmobile_smp_scu_notifier_call,
  };

  void __init shmobile_smp_scu_prepare_cpus(unsigned int max_cpus)
  {

  	/* install boot code shared by all CPUs */
  	shmobile_boot_fn = virt_to_phys(shmobile_smp_boot);
  	shmobile_boot_arg = MPIDR_HWID_BITMASK;

  
  	/* enable SCU and cache coherency on booting CPU */
  	scu_enable(shmobile_scu_base);
  	scu_power_mode(shmobile_scu_base, SCU_PM_NORMAL);

  
  	/* Use CPU notifier for reset vector control */
  	register_cpu_notifier(&shmobile_smp_scu_notifier);

  }

  #ifdef CONFIG_HOTPLUG_CPU
  void shmobile_smp_scu_cpu_die(unsigned int cpu)
  {

  	/* For this particular CPU deregister boot vector */
  	shmobile_smp_hook(cpu, 0, 0);

  	dsb();
  	flush_cache_all();
  
  	/* disable cache coherency */
  	scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);

  	/* jump to shared mach-shmobile sleep / reset code */
  	shmobile_smp_sleep();

  }
  
  static int shmobile_smp_scu_psr_core_disabled(int cpu)
  {
  	unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);
  
  	if ((__raw_readl(shmobile_scu_base + 8) & mask) == mask)
  		return 1;
  
  	return 0;
  }
  
  int shmobile_smp_scu_cpu_kill(unsigned int cpu)
  {
  	int k;
  
  	/* this function is running on another CPU than the offline target,
  	 * here we need wait for shutdown code in platform_cpu_die() to
  	 * finish before asking SoC-specific code to power off the CPU core.
  	 */
  	for (k = 0; k < 1000; k++) {
  		if (shmobile_smp_scu_psr_core_disabled(cpu))
  			return 1;
  
  		mdelay(1);
  	}
  
  	return 0;
  }
  #endif