ip32-reset.c

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/*
 * 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 Keith M Wesolowski
 * Copyright (C) 2001 Paul Mundt
 * Copyright (C) 2003 Guido Guenther <[email protected]>
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/notifier.h>
#include <linux/delay.h>
#include <linux/ds17287rtc.h>
#include <linux/interrupt.h>
#include <linux/pm.h>

#include <asm/addrspace.h>
#include <asm/irq.h>
#include <asm/reboot.h>
#include <asm/wbflush.h>
#include <asm/ip32/mace.h>
#include <asm/ip32/crime.h>
#include <asm/ip32/ip32_ints.h>

#define POWERDOWN_TIMEOUT   120
/*
 * Blink frequency during reboot grace period and when panicked.
 */
#define POWERDOWN_FREQ      (HZ / 4)
#define PANIC_FREQ      (HZ / 8)

static struct timer_list power_timer, blink_timer, debounce_timer;
static int has_panicked, shuting_down;

static void ip32_machine_restart(char *command) __attribute__((noreturn));
static void ip32_machine_halt(void) __attribute__((noreturn));
static void ip32_machine_power_off(void) __attribute__((noreturn));

static void ip32_machine_restart(char *cmd)
{
    crime->control = CRIME_CONTROL_HARD_RESET;
    while (1);
}

static inline void ip32_machine_halt(void)
{
    ip32_machine_power_off();
}

static void ip32_machine_power_off(void)
{
    unsigned char reg_a, xctrl_a, xctrl_b;

    disable_irq(MACEISA_RTC_IRQ);
    reg_a = CMOS_READ(RTC_REG_A);

    /* setup for kickstart & wake-up (DS12287 Ref. Man. p. 19) */
    reg_a &= ~DS_REGA_DV2;
    reg_a |= DS_REGA_DV1;

    CMOS_WRITE(reg_a | DS_REGA_DV0, RTC_REG_A);
    wbflush();
    xctrl_b = CMOS_READ(DS_B1_XCTRL4B)
           | DS_XCTRL4B_ABE | DS_XCTRL4B_KFE;
    CMOS_WRITE(xctrl_b, DS_B1_XCTRL4B);
    xctrl_a = CMOS_READ(DS_B1_XCTRL4A) & ~DS_XCTRL4A_IFS;
    CMOS_WRITE(xctrl_a, DS_B1_XCTRL4A);
    wbflush();
    /* adios amigos... */
    CMOS_WRITE(xctrl_a | DS_XCTRL4A_PAB, DS_B1_XCTRL4A);
    CMOS_WRITE(reg_a, RTC_REG_A);
    wbflush();
    while (1);
}

static void power_timeout(unsigned long data)
{
    ip32_machine_power_off();
}

static void blink_timeout(unsigned long data)
{
    unsigned long led = mace->perif.ctrl.misc ^ MACEISA_LED_RED;
    mace->perif.ctrl.misc = led;
    mod_timer(&blink_timer, jiffies + data);
}

static void debounce(unsigned long data)
{
    unsigned char reg_a, reg_c, xctrl_a;

    reg_c = CMOS_READ(RTC_INTR_FLAGS);
    reg_a = CMOS_READ(RTC_REG_A);
    CMOS_WRITE(reg_a | DS_REGA_DV0, RTC_REG_A);
    wbflush();
    xctrl_a = CMOS_READ(DS_B1_XCTRL4A);
    if ((xctrl_a & DS_XCTRL4A_IFS) || (reg_c & RTC_IRQF )) {
        /* Interrupt still being sent. */
        debounce_timer.expires = jiffies + 50;
        add_timer(&debounce_timer);

        /* clear interrupt source */
        CMOS_WRITE(xctrl_a & ~DS_XCTRL4A_IFS, DS_B1_XCTRL4A);
        CMOS_WRITE(reg_a & ~DS_REGA_DV0, RTC_REG_A);
        return;
    }
    CMOS_WRITE(reg_a & ~DS_REGA_DV0, RTC_REG_A);

    if (has_panicked)
        ip32_machine_restart(NULL);

    enable_irq(MACEISA_RTC_IRQ);
}

static inline void ip32_power_button(void)
{
    if (has_panicked)
        return;

    if (shuting_down || kill_cad_pid(SIGINT, 1)) {
        /* No init process or button pressed twice.  */
        ip32_machine_power_off();
    }

    shuting_down = 1;
    blink_timer.data = POWERDOWN_FREQ;
    blink_timeout(POWERDOWN_FREQ);

    init_timer(&power_timer);
    power_timer.function = power_timeout;
    power_timer.expires = jiffies + POWERDOWN_TIMEOUT * HZ;
    add_timer(&power_timer);
}

static irqreturn_t ip32_rtc_int(int irq, void *dev_id)
{
    unsigned char reg_c;

    reg_c = CMOS_READ(RTC_INTR_FLAGS);
    if (!(reg_c & RTC_IRQF)) {
        printk(KERN_WARNING
            "%s: RTC IRQ without RTC_IRQF\n", __func__);
    }
    /* Wait until interrupt goes away */
    disable_irq_nosync(MACEISA_RTC_IRQ);
    init_timer(&debounce_timer);
    debounce_timer.function = debounce;
    debounce_timer.expires = jiffies + 50;
    add_timer(&debounce_timer);

    printk(KERN_DEBUG "Power button pressed\n");
    ip32_power_button();
    return IRQ_HANDLED;
}

static int panic_event(struct notifier_block *this, unsigned long event,
               void *ptr)
{
    unsigned long led;

    if (has_panicked)
        return NOTIFY_DONE;
    has_panicked = 1;

    /* turn off the green LED */
    led = mace->perif.ctrl.misc | MACEISA_LED_GREEN;
    mace->perif.ctrl.misc = led;

    blink_timer.data = PANIC_FREQ;
    blink_timeout(PANIC_FREQ);

    return NOTIFY_DONE;
}

static struct notifier_block panic_block = {
    .notifier_call = panic_event,
};

static __init int ip32_reboot_setup(void)
{
    /* turn on the green led only */
    unsigned long led = mace->perif.ctrl.misc;
    led |= MACEISA_LED_RED;
    led &= ~MACEISA_LED_GREEN;
    mace->perif.ctrl.misc = led;

    _machine_restart = ip32_machine_restart;
    _machine_halt = ip32_machine_halt;
    pm_power_off = ip32_machine_power_off;

    init_timer(&blink_timer);
    blink_timer.function = blink_timeout;
    atomic_notifier_chain_register(&panic_notifier_list, &panic_block);

    if (request_irq(MACEISA_RTC_IRQ, ip32_rtc_int, 0, "rtc", NULL))
        panic("Can't allocate MACEISA RTC IRQ");

    return 0;
}

subsys_initcall(ip32_reboot_setup);