/*
   * arch/sh/kernel/smp.c
   *
   * SMP support for the SuperH processors.
   *

   * Copyright (C) 2002 - 2010 Paul Mundt

   * Copyright (C) 2006 - 2007 Akio Idehara

   *

   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.

   */

  #include <linux/err.h>

  #include <linux/cache.h>
  #include <linux/cpumask.h>
  #include <linux/delay.h>
  #include <linux/init.h>

  #include <linux/spinlock.h>

  #include <linux/mm.h>

  #include <linux/module.h>

  #include <linux/cpu.h>

  #include <linux/interrupt.h>

  #include <linux/sched.h>

  #include <linux/atomic.h>

  #include <asm/processor.h>
  #include <asm/system.h>
  #include <asm/mmu_context.h>
  #include <asm/smp.h>

  #include <asm/cacheflush.h>
  #include <asm/sections.h>

  int __cpu_number_map[NR_CPUS];		/* Map physical to logical */
  int __cpu_logical_map[NR_CPUS];		/* Map logical to physical */

  struct plat_smp_ops *mp_ops = NULL;

  /* State of each CPU */
  DEFINE_PER_CPU(int, cpu_state) = { 0 };

  void __cpuinit register_smp_ops(struct plat_smp_ops *ops)
  {
  	if (mp_ops)
  		printk(KERN_WARNING "Overriding previously set SMP ops
  ");
  
  	mp_ops = ops;
  }

  static inline void __cpuinit smp_store_cpu_info(unsigned int cpu)

  {

  	struct sh_cpuinfo *c = cpu_data + cpu;

  	memcpy(c, &boot_cpu_data, sizeof(struct sh_cpuinfo));

  	c->loops_per_jiffy = loops_per_jiffy;

  }
  
  void __init smp_prepare_cpus(unsigned int max_cpus)
  {
  	unsigned int cpu = smp_processor_id();

  	init_new_context(current, &init_mm);
  	current_thread_info()->cpu = cpu;

  	mp_ops->prepare_cpus(max_cpus);

  
  #ifndef CONFIG_HOTPLUG_CPU

  	init_cpu_present(&cpu_possible_map);

  #endif

  }

  void __init smp_prepare_boot_cpu(void)

  {
  	unsigned int cpu = smp_processor_id();

  	__cpu_number_map[0] = cpu;
  	__cpu_logical_map[0] = cpu;

  	set_cpu_online(cpu, true);
  	set_cpu_possible(cpu, true);

  
  	per_cpu(cpu_state, cpu) = CPU_ONLINE;

  }

  #ifdef CONFIG_HOTPLUG_CPU
  void native_cpu_die(unsigned int cpu)
  {
  	unsigned int i;
  
  	for (i = 0; i < 10; i++) {
  		smp_rmb();
  		if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
  			if (system_state == SYSTEM_RUNNING)
  				pr_info("CPU %u is now offline
  ", cpu);
  
  			return;
  		}
  
  		msleep(100);
  	}
  
  	pr_err("CPU %u didn't die...
  ", cpu);
  }
  
  int native_cpu_disable(unsigned int cpu)
  {
  	return cpu == 0 ? -EPERM : 0;
  }
  
  void play_dead_common(void)
  {
  	idle_task_exit();
  	irq_ctx_exit(raw_smp_processor_id());
  	mb();
  
  	__get_cpu_var(cpu_state) = CPU_DEAD;
  	local_irq_disable();
  }
  
  void native_play_dead(void)
  {
  	play_dead_common();
  }
  
  int __cpu_disable(void)
  {
  	unsigned int cpu = smp_processor_id();
  	struct task_struct *p;
  	int ret;
  
  	ret = mp_ops->cpu_disable(cpu);
  	if (ret)
  		return ret;
  
  	/*
  	 * Take this CPU offline.  Once we clear this, we can't return,
  	 * and we must not schedule until we're ready to give up the cpu.
  	 */
  	set_cpu_online(cpu, false);
  
  	/*
  	 * OK - migrate IRQs away from this CPU
  	 */
  	migrate_irqs();
  
  	/*
  	 * Stop the local timer for this CPU.
  	 */
  	local_timer_stop(cpu);
  
  	/*
  	 * Flush user cache and TLB mappings, and then remove this CPU
  	 * from the vm mask set of all processes.
  	 */
  	flush_cache_all();
  	local_flush_tlb_all();
  
  	read_lock(&tasklist_lock);
  	for_each_process(p)
  		if (p->mm)
  			cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
  	read_unlock(&tasklist_lock);
  
  	return 0;
  }
  #else /* ... !CONFIG_HOTPLUG_CPU */

  int native_cpu_disable(unsigned int cpu)

  {
  	return -ENOSYS;
  }
  
  void native_cpu_die(unsigned int cpu)
  {
  	/* We said "no" in __cpu_disable */
  	BUG();
  }
  
  void native_play_dead(void)
  {
  	BUG();
  }
  #endif

  asmlinkage void __cpuinit start_secondary(void)

  {

  	unsigned int cpu = smp_processor_id();

  	struct mm_struct *mm = &init_mm;

  	enable_mmu();

  	atomic_inc(&mm->mm_count);
  	atomic_inc(&mm->mm_users);
  	current->active_mm = mm;

  	enter_lazy_tlb(mm, current);

  	local_flush_tlb_all();

  
  	per_cpu_trap_init();
  
  	preempt_disable();

  	notify_cpu_starting(cpu);

  	local_irq_enable();

  	/* Enable local timers */
  	local_timer_setup(cpu);

  	calibrate_delay();

  	smp_store_cpu_info(cpu);

  	set_cpu_online(cpu, true);

  	per_cpu(cpu_state, cpu) = CPU_ONLINE;

  	cpu_idle();

  }

  extern struct {
  	unsigned long sp;
  	unsigned long bss_start;
  	unsigned long bss_end;
  	void *start_kernel_fn;
  	void *cpu_init_fn;
  	void *thread_info;
  } stack_start;
  
  int __cpuinit __cpu_up(unsigned int cpu)

  {

  	struct task_struct *tsk;
  	unsigned long timeout;

  	tsk = cpu_data[cpu].idle;
  	if (!tsk) {
  		tsk = fork_idle(cpu);
  		if (IS_ERR(tsk)) {
  			pr_err("Failed forking idle task for cpu %d
  ", cpu);
  			return PTR_ERR(tsk);
  		}
  
  		cpu_data[cpu].idle = tsk;

  	}

  	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;

  	/* Fill in data in head.S for secondary cpus */
  	stack_start.sp = tsk->thread.sp;
  	stack_start.thread_info = tsk->stack;
  	stack_start.bss_start = 0; /* don't clear bss for secondary cpus */
  	stack_start.start_kernel_fn = start_secondary;

  	flush_icache_range((unsigned long)&stack_start,
  			   (unsigned long)&stack_start + sizeof(stack_start));
  	wmb();

  	mp_ops->start_cpu(cpu, (unsigned long)_stext);

  	timeout = jiffies + HZ;
  	while (time_before(jiffies, timeout)) {
  		if (cpu_online(cpu))
  			break;
  
  		udelay(10);

  		barrier();

  	}
  
  	if (cpu_online(cpu))
  		return 0;
  
  	return -ENOENT;

  }
  
  void __init smp_cpus_done(unsigned int max_cpus)
  {

  	unsigned long bogosum = 0;
  	int cpu;
  
  	for_each_online_cpu(cpu)
  		bogosum += cpu_data[cpu].loops_per_jiffy;
  
  	printk(KERN_INFO "SMP: Total of %d processors activated "
  	       "(%lu.%02lu BogoMIPS).
  ", num_online_cpus(),
  	       bogosum / (500000/HZ),
  	       (bogosum / (5000/HZ)) % 100);

  }
  
  void smp_send_reschedule(int cpu)
  {

  	mp_ops->send_ipi(cpu, SMP_MSG_RESCHEDULE);

  }

  void smp_send_stop(void)
  {

  	smp_call_function(stop_this_cpu, 0, 0);

  }

  void arch_send_call_function_ipi_mask(const struct cpumask *mask)

  {

  	int cpu;

  	for_each_cpu(cpu, mask)

  		mp_ops->send_ipi(cpu, SMP_MSG_FUNCTION);

  }

  void arch_send_call_function_single_ipi(int cpu)
  {

  	mp_ops->send_ipi(cpu, SMP_MSG_FUNCTION_SINGLE);

  }

  void smp_timer_broadcast(const struct cpumask *mask)

  {
  	int cpu;

  	for_each_cpu(cpu, mask)

  		mp_ops->send_ipi(cpu, SMP_MSG_TIMER);

  }
  
  static void ipi_timer(void)
  {
  	irq_enter();

  	local_timer_interrupt();

  	irq_exit();
  }

  void smp_message_recv(unsigned int msg)
  {
  	switch (msg) {
  	case SMP_MSG_FUNCTION:
  		generic_smp_call_function_interrupt();
  		break;
  	case SMP_MSG_RESCHEDULE:

  		scheduler_ipi();

  		break;
  	case SMP_MSG_FUNCTION_SINGLE:
  		generic_smp_call_function_single_interrupt();
  		break;

  	case SMP_MSG_TIMER:
  		ipi_timer();
  		break;

  	default:
  		printk(KERN_WARNING "SMP %d: %s(): unknown IPI %d
  ",
  		       smp_processor_id(), __func__, msg);
  		break;
  	}
  }

  /* Not really SMP stuff ... */
  int setup_profiling_timer(unsigned int multiplier)
  {
  	return 0;
  }

  static void flush_tlb_all_ipi(void *info)
  {
  	local_flush_tlb_all();
  }
  
  void flush_tlb_all(void)
  {

  	on_each_cpu(flush_tlb_all_ipi, 0, 1);

  }
  
  static void flush_tlb_mm_ipi(void *mm)
  {
  	local_flush_tlb_mm((struct mm_struct *)mm);
  }
  
  /*
   * The following tlb flush calls are invoked when old translations are
   * being torn down, or pte attributes are changing. For single threaded
   * address spaces, a new context is obtained on the current cpu, and tlb
   * context on other cpus are invalidated to force a new context allocation
   * at switch_mm time, should the mm ever be used on other cpus. For
   * multithreaded address spaces, intercpu interrupts have to be sent.
   * Another case where intercpu interrupts are required is when the target
   * mm might be active on another cpu (eg debuggers doing the flushes on
   * behalf of debugees, kswapd stealing pages from another process etc).
   * Kanoj 07/00.
   */

  void flush_tlb_mm(struct mm_struct *mm)
  {
  	preempt_disable();
  
  	if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {

  		smp_call_function(flush_tlb_mm_ipi, (void *)mm, 1);

  	} else {
  		int i;
  		for (i = 0; i < num_online_cpus(); i++)
  			if (smp_processor_id() != i)
  				cpu_context(i, mm) = 0;
  	}
  	local_flush_tlb_mm(mm);
  
  	preempt_enable();
  }
  
  struct flush_tlb_data {
  	struct vm_area_struct *vma;
  	unsigned long addr1;
  	unsigned long addr2;
  };
  
  static void flush_tlb_range_ipi(void *info)
  {
  	struct flush_tlb_data *fd = (struct flush_tlb_data *)info;
  
  	local_flush_tlb_range(fd->vma, fd->addr1, fd->addr2);
  }
  
  void flush_tlb_range(struct vm_area_struct *vma,
  		     unsigned long start, unsigned long end)
  {
  	struct mm_struct *mm = vma->vm_mm;
  
  	preempt_disable();
  	if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
  		struct flush_tlb_data fd;
  
  		fd.vma = vma;
  		fd.addr1 = start;
  		fd.addr2 = end;

  		smp_call_function(flush_tlb_range_ipi, (void *)&fd, 1);

  	} else {
  		int i;
  		for (i = 0; i < num_online_cpus(); i++)
  			if (smp_processor_id() != i)
  				cpu_context(i, mm) = 0;
  	}
  	local_flush_tlb_range(vma, start, end);
  	preempt_enable();
  }
  
  static void flush_tlb_kernel_range_ipi(void *info)
  {
  	struct flush_tlb_data *fd = (struct flush_tlb_data *)info;
  
  	local_flush_tlb_kernel_range(fd->addr1, fd->addr2);
  }
  
  void flush_tlb_kernel_range(unsigned long start, unsigned long end)
  {
  	struct flush_tlb_data fd;
  
  	fd.addr1 = start;
  	fd.addr2 = end;

  	on_each_cpu(flush_tlb_kernel_range_ipi, (void *)&fd, 1);

  }
  
  static void flush_tlb_page_ipi(void *info)
  {
  	struct flush_tlb_data *fd = (struct flush_tlb_data *)info;
  
  	local_flush_tlb_page(fd->vma, fd->addr1);
  }
  
  void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
  {
  	preempt_disable();
  	if ((atomic_read(&vma->vm_mm->mm_users) != 1) ||
  	    (current->mm != vma->vm_mm)) {
  		struct flush_tlb_data fd;
  
  		fd.vma = vma;
  		fd.addr1 = page;

  		smp_call_function(flush_tlb_page_ipi, (void *)&fd, 1);

  	} else {
  		int i;
  		for (i = 0; i < num_online_cpus(); i++)
  			if (smp_processor_id() != i)
  				cpu_context(i, vma->vm_mm) = 0;
  	}
  	local_flush_tlb_page(vma, page);
  	preempt_enable();
  }
  
  static void flush_tlb_one_ipi(void *info)
  {
  	struct flush_tlb_data *fd = (struct flush_tlb_data *)info;
  	local_flush_tlb_one(fd->addr1, fd->addr2);
  }
  
  void flush_tlb_one(unsigned long asid, unsigned long vaddr)
  {
  	struct flush_tlb_data fd;
  
  	fd.addr1 = asid;
  	fd.addr2 = vaddr;

  	smp_call_function(flush_tlb_one_ipi, (void *)&fd, 1);

  	local_flush_tlb_one(asid, vaddr);
  }