/*
 *	linux/arch/alpha/kernel/smp.c
 *
 *      2001-07-09 Phil Ezolt (Phillip.Ezolt@compaq.com)
 *            Renamed modified smp_call_function to smp_call_function_on_cpu()
 *            Created an function that conforms to the old calling convention
 *            of smp_call_function().
 *
 *            This is helpful for DCPI.
 *
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/irq.h>
#include <linux/cache.h>
#include <linux/profile.h>
#include <linux/bitops.h>
#include <linux/cpu.h>

#include <asm/hwrpb.h>
#include <asm/ptrace.h>
#include <linux/atomic.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>

#include "proto.h"
#include "irq_impl.h"


#define DEBUG_SMP 0
#if DEBUG_SMP
#define DBGS(args)	printk args
#else
#define DBGS(args)
#endif

/* A collection of per-processor data.  */
struct cpuinfo_alpha cpu_data[NR_CPUS];
EXPORT_SYMBOL(cpu_data);

/* A collection of single bit ipi messages.  */
static struct {
	unsigned long bits ____cacheline_aligned;
} ipi_data[NR_CPUS] __cacheline_aligned;

enum ipi_message_type {
	IPI_RESCHEDULE,
	IPI_CALL_FUNC,
	IPI_CALL_FUNC_SINGLE,
	IPI_CPU_STOP,
};

/* Set to a secondary's cpuid when it comes online.  */
static int smp_secondary_alive = 0;

int smp_num_probed;		/* Internal processor count */
int smp_num_cpus = 1;		/* Number that came online.  */
EXPORT_SYMBOL(smp_num_cpus);

/*
 * Called by both boot and secondaries to move global data into
 *  per-processor storage.
 */
static inline void __init
smp_store_cpu_info(int cpuid)
{
	cpu_data[cpuid].loops_per_jiffy = loops_per_jiffy;
	cpu_data[cpuid].last_asn = ASN_FIRST_VERSION;
	cpu_data[cpuid].need_new_asn = 0;
	cpu_data[cpuid].asn_lock = 0;
}

/*
 * Ideally sets up per-cpu profiling hooks.  Doesn't do much now...
 */
static inline void __init
smp_setup_percpu_timer(int cpuid)
{
	cpu_data[cpuid].prof_counter = 1;
	cpu_data[cpuid].prof_multiplier = 1;
}

static void __init
wait_boot_cpu_to_stop(int cpuid)
{
	unsigned long stop = jiffies + 10*HZ;

	while (time_before(jiffies, stop)) {
	        if (!smp_secondary_alive)
			return;
		barrier();
	}

	printk("wait_boot_cpu_to_stop: FAILED on CPU %d, hanging now\n", cpuid);
	for (;;)
		barrier();
}

/*
 * Where secondaries begin a life of C.
 */
void __cpuinit
smp_callin(void)
{
	int cpuid = hard_smp_processor_id();

	if (cpu_online(cpuid)) {
		printk("??, cpu 0x%x already present??\n", cpuid);
		BUG();
	}
	set_cpu_online(cpuid, true);

	/* Turn on machine checks.  */
	wrmces(7);

	/* Set trap vectors.  */
	trap_init();

	/* Set interrupt vector.  */
	wrent(entInt, 0);

	/* Get our local ticker going. */
	smp_setup_percpu_timer(cpuid);

	/* Call platform-specific callin, if specified */
	if (alpha_mv.smp_callin) alpha_mv.smp_callin();

	/* All kernel threads share the same mm context.  */
	atomic_inc(&init_mm.mm_count);
	current->active_mm = &init_mm;

	/* inform the notifiers about the new cpu */
	notify_cpu_starting(cpuid);

	/* Must have completely accurate bogos.  */
	local_irq_enable();

	/* Wait boot CPU to stop with irq enabled before running
	   calibrate_delay. */
	wait_boot_cpu_to_stop(cpuid);
	mb();
	calibrate_delay();

	smp_store_cpu_info(cpuid);
	/* Allow master to continue only after we written loops_per_jiffy.  */
	wmb();
	smp_secondary_alive = 1;

	DBGS(("smp_callin: commencing CPU %d current %p active_mm %p\n",
	      cpuid, current, current->active_mm));