/*
 * 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.
 *
 * Copyright (C) 2001, 06 by Ralf Baechle (ralf@linux-mips.org)
 * Copyright (C) 2001 MIPS Technologies, Inc.
 */
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/pm.h>
#include <linux/types.h>
#include <linux/reboot.h>
#include <linux/delay.h>

#include <asm/compiler.h>
#include <asm/idle.h>
#include <asm/mipsregs.h>
#include <asm/reboot.h>

/*
 * Urgs ...  Too many MIPS machines to handle this in a generic way.
 * So handle all using function pointers to machine specific
 * functions.
 */
void (*_machine_restart)(char *command);
void (*_machine_halt)(void);
void (*pm_power_off)(void);

EXPORT_SYMBOL(pm_power_off);

static void machine_hang(void)
{
        /*
         * We're hanging the system so we don't want to be interrupted anymore.
         * Any interrupt handlers that ran would at best be useless & at worst
         * go awry because the system isn't in a functional state.
         */
        local_irq_disable();

        /*
         * Mask all interrupts, giving us a better chance of remaining in the
         * low power wait state.
         */
        clear_c0_status(ST0_IM);

        while (true) {
                if (cpu_has_mips_r) {
                        /*
                         * We know that the wait instruction is supported so
                         * make use of it directly, leaving interrupts
                         * disabled.
                         */
                        asm volatile(
                                ".set   push\n\t"
                                ".set   " MIPS_ISA_ARCH_LEVEL "\n\t"
                                "wait\n\t"
                                ".set   pop");
                } else if (cpu_wait) {
                        /*
                         * Try the cpu_wait() callback. This isn't ideal since
                         * it'll re-enable interrupts, but that ought to be
                         * harmless given that they're all masked.
                         */
                        cpu_wait();
                        local_irq_disable();
                } else {
                        /*
                         * We're going to burn some power running round the
                         * loop, but we don't really have a choice. This isn't
                         * a path we should expect to run for long during
                         * typical use anyway.
                         */
                }

                /*
                 * In most modern MIPS CPUs interrupts will cause the wait
                 * instruction to graduate even when disabled, and in some
                 * cases even when masked. In order to prevent a timer
                 * interrupt from continuously taking us out of the low power
                 * wait state, we clear any pending timer interrupt here.
                 */
                if (cpu_has_counter)
                        write_c0_compare(0);
        }
}

void machine_restart(char *command)
{
        if (_machine_restart)
                _machine_restart(command);

#ifdef CONFIG_SMP
        preempt_disable();
        smp_send_stop();
#endif
        do_kernel_restart(command);
        mdelay(1000);
        pr_emerg("Reboot failed -- System halted\n");
        machine_hang();
}

void machine_halt(void)
{
        if (_machine_halt)
                _machine_halt();

#ifdef CONFIG_SMP
        preempt_disable();
        smp_send_stop();
#endif
        machine_hang();
}

void machine_power_off(void)
{
        do_kernel_power_off();

#ifdef CONFIG_SMP
        preempt_disable();
        smp_send_stop();
#endif
        machine_hang();
}