root/arch/x86/mach-voyager/voyager_thread.c

DEFINITIONS

1. execute
2. check_from_kernel
3. check_continuing_condition
4. thread
5. voyager_thread_start
6. voyager_thread_stop

/* -*- mode: c; c-basic-offset: 8 -*- */

/* Copyright (C) 2001
 *
 * Author: J.E.J.Bottomley@HansenPartnership.com
 *
 * This module provides the machine status monitor thread for the
 * voyager architecture.  This allows us to monitor the machine
 * environment (temp, voltage, fan function) and the front panel and
 * internal UPS.  If a fault is detected, this thread takes corrective
 * action (usually just informing init)
 * */

#include <linux/module.h>
#include <linux/mm.h>
#include <linux/kernel_stat.h>
#include <linux/delay.h>
#include <linux/mc146818rtc.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/kmod.h>
#include <linux/completion.h>
#include <linux/sched.h>
#include <linux/kthread.h>
#include <asm/desc.h>
#include <asm/voyager.h>
#include <asm/vic.h>
#include <asm/mtrr.h>
#include <asm/msr.h>

struct task_struct *voyager_thread;
static __u8 set_timeout;

static int execute(const char *string)
{
        int ret;

        char *envp[] = {
                "HOME=/",
                "TERM=linux",
                "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
                NULL,
        };
        char *argv[] = {
                "/bin/bash",
                "-c",
                (char *)string,
                NULL,
        };

        if ((ret =
             call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC)) != 0) {
                printk(KERN_ERR "Voyager failed to run \"%s\": %i\n", string,
                       ret);
        }
        return ret;
}

static void check_from_kernel(void)
{
        if (voyager_status.switch_off) {

                /* FIXME: This should be configurable via proc */
                execute("umask 600; echo 0 > /etc/initrunlvl; kill -HUP 1");
        } else if (voyager_status.power_fail) {
                VDEBUG(("Voyager daemon detected AC power failure\n"));

                /* FIXME: This should be configureable via proc */
                execute("umask 600; echo F > /etc/powerstatus; kill -PWR 1");
                set_timeout = 1;
        }
}

static void check_continuing_condition(void)
{
        if (voyager_status.power_fail) {
                __u8 data;
                voyager_cat_psi(VOYAGER_PSI_SUBREAD,
                                VOYAGER_PSI_AC_FAIL_REG, &data);
                if ((data & 0x1f) == 0) {
                        /* all power restored */
                        printk(KERN_NOTICE
                               "VOYAGER AC power restored, cancelling shutdown\n");
                        /* FIXME: should be user configureable */
                        execute
                            ("umask 600; echo O > /etc/powerstatus; kill -PWR 1");
                        set_timeout = 0;
                }
        }
}

static int thread(void *unused)
{
        printk(KERN_NOTICE "Voyager starting monitor thread\n");

        for (;;) {
                set_current_state(TASK_INTERRUPTIBLE);
                schedule_timeout(set_timeout ? HZ : MAX_SCHEDULE_TIMEOUT);

                VDEBUG(("Voyager Daemon awoken\n"));
                if (voyager_status.request_from_kernel == 0) {
                        /* probably awoken from timeout */
                        check_continuing_condition();
                } else {
                        check_from_kernel();
                        voyager_status.request_from_kernel = 0;
                }
        }
}

static int __init voyager_thread_start(void)
{
        voyager_thread = kthread_run(thread, NULL, "kvoyagerd");
        if (IS_ERR(voyager_thread)) {
                printk(KERN_ERR
                       "Voyager: Failed to create system monitor thread.\n");
                return PTR_ERR(voyager_thread);
        }
        return 0;
}

static void __exit voyager_thread_stop(void)
{
        kthread_stop(voyager_thread);
}

module_init(voyager_thread_start);
module_exit(voyager_thread_stop);