Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Intel 21285 watchdog driver |
| 3 | * Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998 |
| 4 | * |
| 5 | * based on |
| 6 | * |
| 7 | * SoftDog 0.05: A Software Watchdog Device |
| 8 | * |
| 9 | * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or |
| 12 | * modify it under the terms of the GNU General Public License |
| 13 | * as published by the Free Software Foundation; either version |
| 14 | * 2 of the License, or (at your option) any later version. |
| 15 | * |
| 16 | */ |
| 17 | |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/moduleparam.h> |
| 20 | #include <linux/types.h> |
| 21 | #include <linux/kernel.h> |
| 22 | #include <linux/fs.h> |
| 23 | #include <linux/mm.h> |
| 24 | #include <linux/miscdevice.h> |
| 25 | #include <linux/watchdog.h> |
| 26 | #include <linux/reboot.h> |
| 27 | #include <linux/init.h> |
| 28 | #include <linux/interrupt.h> |
| 29 | |
| 30 | #include <asm/irq.h> |
| 31 | #include <asm/uaccess.h> |
| 32 | #include <asm/hardware.h> |
| 33 | #include <asm/mach-types.h> |
| 34 | #include <asm/hardware/dec21285.h> |
| 35 | |
| 36 | /* |
| 37 | * Define this to stop the watchdog actually rebooting the machine. |
| 38 | */ |
| 39 | #undef ONLY_TESTING |
| 40 | |
| 41 | static unsigned int soft_margin = 60; /* in seconds */ |
| 42 | static unsigned int reload; |
| 43 | static unsigned long timer_alive; |
| 44 | |
| 45 | #ifdef ONLY_TESTING |
| 46 | /* |
| 47 | * If the timer expires.. |
| 48 | */ |
| 49 | static void watchdog_fire(int irq, void *dev_id, struct pt_regs *regs) |
| 50 | { |
| 51 | printk(KERN_CRIT "Watchdog: Would Reboot.\n"); |
| 52 | *CSR_TIMER4_CNTL = 0; |
| 53 | *CSR_TIMER4_CLR = 0; |
| 54 | } |
| 55 | #endif |
| 56 | |
| 57 | /* |
| 58 | * Refresh the timer. |
| 59 | */ |
| 60 | static void watchdog_ping(void) |
| 61 | { |
| 62 | *CSR_TIMER4_LOAD = reload; |
| 63 | } |
| 64 | |
| 65 | /* |
| 66 | * Allow only one person to hold it open |
| 67 | */ |
| 68 | static int watchdog_open(struct inode *inode, struct file *file) |
| 69 | { |
| 70 | int ret; |
| 71 | |
| 72 | if (*CSR_SA110_CNTL & (1 << 13)) |
| 73 | return -EBUSY; |
| 74 | |
| 75 | if (test_and_set_bit(1, &timer_alive)) |
| 76 | return -EBUSY; |
| 77 | |
| 78 | reload = soft_margin * (mem_fclk_21285 / 256); |
| 79 | |
| 80 | *CSR_TIMER4_CLR = 0; |
| 81 | watchdog_ping(); |
| 82 | *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD |
| 83 | | TIMER_CNTL_DIV256; |
| 84 | |
| 85 | #ifdef ONLY_TESTING |
| 86 | ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL); |
| 87 | if (ret) { |
| 88 | *CSR_TIMER4_CNTL = 0; |
| 89 | clear_bit(1, &timer_alive); |
| 90 | } |
| 91 | #else |
| 92 | /* |
| 93 | * Setting this bit is irreversible; once enabled, there is |
| 94 | * no way to disable the watchdog. |
| 95 | */ |
| 96 | *CSR_SA110_CNTL |= 1 << 13; |
| 97 | |
| 98 | ret = 0; |
| 99 | #endif |
| 100 | nonseekable_open(inode, file); |
| 101 | return ret; |
| 102 | } |
| 103 | |
| 104 | /* |
| 105 | * Shut off the timer. |
| 106 | * Note: if we really have enabled the watchdog, there |
| 107 | * is no way to turn off. |
| 108 | */ |
| 109 | static int watchdog_release(struct inode *inode, struct file *file) |
| 110 | { |
| 111 | #ifdef ONLY_TESTING |
| 112 | free_irq(IRQ_TIMER4, NULL); |
| 113 | clear_bit(1, &timer_alive); |
| 114 | #endif |
| 115 | return 0; |
| 116 | } |
| 117 | |
| 118 | static ssize_t |
| 119 | watchdog_write(struct file *file, const char *data, size_t len, loff_t *ppos) |
| 120 | { |
| 121 | /* |
| 122 | * Refresh the timer. |
| 123 | */ |
| 124 | if (len) |
| 125 | watchdog_ping(); |
| 126 | |
| 127 | return len; |
| 128 | } |
| 129 | |
| 130 | static struct watchdog_info ident = { |
| 131 | .options = WDIOF_SETTIMEOUT, |
| 132 | .identity = "Footbridge Watchdog", |
| 133 | }; |
| 134 | |
| 135 | static int |
| 136 | watchdog_ioctl(struct inode *inode, struct file *file, unsigned int cmd, |
| 137 | unsigned long arg) |
| 138 | { |
| 139 | unsigned int new_margin; |
| 140 | int ret = -ENOIOCTLCMD; |
| 141 | |
| 142 | switch(cmd) { |
| 143 | case WDIOC_GETSUPPORT: |
| 144 | ret = 0; |
| 145 | if (copy_to_user((void *)arg, &ident, sizeof(ident))) |
| 146 | ret = -EFAULT; |
| 147 | break; |
| 148 | |
| 149 | case WDIOC_GETSTATUS: |
| 150 | case WDIOC_GETBOOTSTATUS: |
| 151 | ret = put_user(0,(int *)arg); |
| 152 | break; |
| 153 | |
| 154 | case WDIOC_KEEPALIVE: |
| 155 | watchdog_ping(); |
| 156 | ret = 0; |
| 157 | break; |
| 158 | |
| 159 | case WDIOC_SETTIMEOUT: |
| 160 | ret = get_user(new_margin, (int *)arg); |
| 161 | if (ret) |
| 162 | break; |
| 163 | |
| 164 | /* Arbitrary, can't find the card's limits */ |
| 165 | if (new_margin < 0 || new_margin > 60) { |
| 166 | ret = -EINVAL; |
| 167 | break; |
| 168 | } |
| 169 | |
| 170 | soft_margin = new_margin; |
| 171 | reload = soft_margin * (mem_fclk_21285 / 256); |
| 172 | watchdog_ping(); |
| 173 | /* Fall */ |
| 174 | case WDIOC_GETTIMEOUT: |
| 175 | ret = put_user(soft_margin, (int *)arg); |
| 176 | break; |
| 177 | } |
| 178 | return ret; |
| 179 | } |
| 180 | |
Arjan van de Ven | 62322d2 | 2006-07-03 00:24:21 -0700 | [diff] [blame] | 181 | static const struct file_operations watchdog_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | .owner = THIS_MODULE, |
| 183 | .llseek = no_llseek, |
| 184 | .write = watchdog_write, |
| 185 | .ioctl = watchdog_ioctl, |
| 186 | .open = watchdog_open, |
| 187 | .release = watchdog_release, |
| 188 | }; |
| 189 | |
| 190 | static struct miscdevice watchdog_miscdev = { |
| 191 | .minor = WATCHDOG_MINOR, |
| 192 | .name = "watchdog", |
| 193 | .fops = &watchdog_fops, |
| 194 | }; |
| 195 | |
| 196 | static int __init footbridge_watchdog_init(void) |
| 197 | { |
| 198 | int retval; |
| 199 | |
| 200 | if (machine_is_netwinder()) |
| 201 | return -ENODEV; |
| 202 | |
| 203 | retval = misc_register(&watchdog_miscdev); |
| 204 | if (retval < 0) |
| 205 | return retval; |
| 206 | |
| 207 | printk("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n", |
| 208 | soft_margin); |
| 209 | |
| 210 | if (machine_is_cats()) |
| 211 | printk("Warning: Watchdog reset may not work on this machine.\n"); |
| 212 | return 0; |
| 213 | } |
| 214 | |
| 215 | static void __exit footbridge_watchdog_exit(void) |
| 216 | { |
| 217 | misc_deregister(&watchdog_miscdev); |
| 218 | } |
| 219 | |
| 220 | MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>"); |
| 221 | MODULE_DESCRIPTION("Footbridge watchdog driver"); |
| 222 | MODULE_LICENSE("GPL"); |
| 223 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
| 224 | |
| 225 | module_param(soft_margin, int, 0); |
| 226 | MODULE_PARM_DESC(soft_margin,"Watchdog timeout in seconds"); |
| 227 | |
| 228 | module_init(footbridge_watchdog_init); |
| 229 | module_exit(footbridge_watchdog_exit); |