Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ] 
  1 /* -*- mode: c; c-basic-offset: 8 -*- */
  2 
  3 /* Copyright (C) 2001
  4  *
  5  * Author: J.E.J.Bottomley@HansenPartnership.com
  6  *
  7  * linux/arch/i386/kernel/voyager_thread.c
  8  *
  9  * This module provides the machine status monitor thread for the
 10  * voyager architecture.  This allows us to monitor the machine
 11  * environment (temp, voltage, fan function) and the front panel and
 12  * internal UPS.  If a fault is detected, this thread takes corrective
 13  * action (usually just informing init)
 14  * */
 15 
 16 #include <linux/module.h>
 17 #include <linux/config.h>
 18 #include <linux/mm.h>
 19 #include <linux/kernel_stat.h>
 20 #include <linux/delay.h>
 21 #include <linux/mc146818rtc.h>
 22 #include <linux/smp_lock.h>
 23 #include <linux/init.h>
 24 #include <linux/bootmem.h>
 25 #include <linux/kmod.h>
 26 #include <linux/completion.h>
 27 #include <linux/sched.h>
 28 #include <asm/desc.h>
 29 #include <asm/voyager.h>
 30 #include <asm/vic.h>
 31 #include <asm/mtrr.h>
 32 #include <asm/msr.h>
 33 
 34 #include <linux/irq.h>
 35 
 36 #define THREAD_NAME "kvoyagerd"
 37 
 38 /* external variables */
 39 int kvoyagerd_running = 0;
 40 DECLARE_MUTEX_LOCKED(kvoyagerd_sem);
 41 
 42 static int thread(void *);
 43 
 44 static __u8 set_timeout = 0;
 45 
 46 /* Start the machine monitor thread.  Return 1 if OK, 0 if fail */
 47 static int __init
 48 voyager_thread_start(void)
 49 {
 50         if(kernel_thread(thread, NULL, CLONE_KERNEL) < 0) {
 51                 /* This is serious, but not fatal */
 52                 printk(KERN_ERR "Voyager: Failed to create system monitor thread!!!\n");
 53                 return 1;
 54         }
 55         return 0;
 56 }
 57 
 58 static int
 59 execute(const char *string)
 60 {
 61         int ret;
 62 
 63         char *envp[] = {
 64                 "HOME=/",
 65                 "TERM=linux",
 66                 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
 67                 NULL,
 68         };
 69         char *argv[] = {
 70                 "/bin/bash",
 71                 "-c",
 72                 (char *)string,
 73                 NULL,
 74         };
 75 
 76         if ((ret = call_usermodehelper(argv[0], argv, envp, 1)) != 0) {
 77                 printk(KERN_ERR "Voyager failed to run \"%s\": %i\n",
 78                        string, ret);
 79         }
 80         return ret;
 81 }
 82 
 83 static void
 84 check_from_kernel(void)
 85 {
 86         if(voyager_status.switch_off) {
 87                 
 88                 /* FIXME: This should be configureable via proc */
 89                 execute("umask 600; echo 0 > /etc/initrunlvl; kill -HUP 1");
 90         } else if(voyager_status.power_fail) {
 91                 VDEBUG(("Voyager daemon detected AC power failure\n"));
 92                 
 93                 /* FIXME: This should be configureable via proc */
 94                 execute("umask 600; echo F > /etc/powerstatus; kill -PWR 1");
 95                 set_timeout = 1;
 96         }
 97 }
 98 
 99 static void
100 check_continuing_condition(void)
101 {
102         if(voyager_status.power_fail) {
103                 __u8 data;
104                 voyager_cat_psi(VOYAGER_PSI_SUBREAD, 
105                                 VOYAGER_PSI_AC_FAIL_REG, &data);
106                 if((data & 0x1f) == 0) {
107                         /* all power restored */
108                         printk(KERN_NOTICE "VOYAGER AC power restored, cancelling shutdown\n");
109                         /* FIXME: should be user configureable */
110                         execute("umask 600; echo O > /etc/powerstatus; kill -PWR 1");
111                         set_timeout = 0;
112                 }
113         }
114 }
115 
116 static void
117 wakeup(unsigned long unused)
118 {
119         up(&kvoyagerd_sem);
120 }
121 
122 static int
123 thread(void *unused)
124 {
125         struct timer_list wakeup_timer;
126 
127         kvoyagerd_running = 1;
128 
129         reparent_to_init();
130         daemonize(THREAD_NAME);
131 
132         set_timeout = 0;
133 
134         init_timer(&wakeup_timer);
135 
136         sigfillset(&current->blocked);
137         current->signal->tty = NULL;
138 
139         printk(KERN_NOTICE "Voyager starting monitor thread\n");
140 
141         for(;;) {
142                 down_interruptible(&kvoyagerd_sem);
143                 VDEBUG(("Voyager Daemon awoken\n"));
144                 if(voyager_status.request_from_kernel == 0) {
145                         /* probably awoken from timeout */
146                         check_continuing_condition();
147                 } else {
148                         check_from_kernel();
149                         voyager_status.request_from_kernel = 0;
150                 }
151                 if(set_timeout) {
152                         del_timer(&wakeup_timer);
153                         wakeup_timer.expires = HZ + jiffies;
154                         wakeup_timer.function = wakeup;
155                         add_timer(&wakeup_timer);
156                 }
157         }
158 }
159 
160 static void __exit
161 voyager_thread_stop(void)
162 {
163         /* FIXME: do nothing at the moment */
164 }
165 
166 module_init(voyager_thread_start);
167 //module_exit(voyager_thread_stop);
168
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