matthieu castet | 90074dc | 2009-06-05 18:57:18 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Watchdog driver for Broadcom BCM47XX |
| 3 | * |
| 4 | * Copyright (C) 2008 Aleksandar Radovanovic <biblbroks@sezampro.rs> |
| 5 | * Copyright (C) 2009 Matthieu CASTET <castet.matthieu@free.fr> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License |
| 9 | * as published by the Free Software Foundation; either version |
| 10 | * 2 of the License, or (at your option) any later version. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/bitops.h> |
| 14 | #include <linux/errno.h> |
| 15 | #include <linux/fs.h> |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/kernel.h> |
| 18 | #include <linux/miscdevice.h> |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/moduleparam.h> |
| 21 | #include <linux/reboot.h> |
| 22 | #include <linux/types.h> |
| 23 | #include <linux/uaccess.h> |
| 24 | #include <linux/watchdog.h> |
| 25 | #include <linux/timer.h> |
| 26 | #include <linux/jiffies.h> |
| 27 | #include <linux/ssb/ssb_embedded.h> |
| 28 | #include <asm/mach-bcm47xx/bcm47xx.h> |
| 29 | |
| 30 | #define DRV_NAME "bcm47xx_wdt" |
| 31 | |
| 32 | #define WDT_DEFAULT_TIME 30 /* seconds */ |
| 33 | #define WDT_MAX_TIME 255 /* seconds */ |
| 34 | |
| 35 | static int wdt_time = WDT_DEFAULT_TIME; |
| 36 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 37 | |
| 38 | module_param(wdt_time, int, 0); |
| 39 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
| 40 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); |
| 41 | |
| 42 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
| 43 | module_param(nowayout, int, 0); |
| 44 | MODULE_PARM_DESC(nowayout, |
| 45 | "Watchdog cannot be stopped once started (default=" |
| 46 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 47 | #endif |
| 48 | |
| 49 | static unsigned long bcm47xx_wdt_busy; |
| 50 | static char expect_release; |
| 51 | static struct timer_list wdt_timer; |
| 52 | static atomic_t ticks; |
| 53 | |
| 54 | static inline void bcm47xx_wdt_hw_start(void) |
| 55 | { |
| 56 | /* this is 2,5s on 100Mhz clock and 2s on 133 Mhz */ |
| 57 | ssb_watchdog_timer_set(&ssb_bcm47xx, 0xfffffff); |
| 58 | } |
| 59 | |
| 60 | static inline int bcm47xx_wdt_hw_stop(void) |
| 61 | { |
| 62 | return ssb_watchdog_timer_set(&ssb_bcm47xx, 0); |
| 63 | } |
| 64 | |
| 65 | static void bcm47xx_timer_tick(unsigned long unused) |
| 66 | { |
| 67 | if (!atomic_dec_and_test(&ticks)) { |
| 68 | bcm47xx_wdt_hw_start(); |
| 69 | mod_timer(&wdt_timer, jiffies + HZ); |
| 70 | } else { |
| 71 | printk(KERN_CRIT DRV_NAME "Watchdog will fire soon!!!\n"); |
| 72 | } |
| 73 | } |
| 74 | |
| 75 | static inline void bcm47xx_wdt_pet(void) |
| 76 | { |
| 77 | atomic_set(&ticks, wdt_time); |
| 78 | } |
| 79 | |
| 80 | static void bcm47xx_wdt_start(void) |
| 81 | { |
| 82 | bcm47xx_wdt_pet(); |
| 83 | bcm47xx_timer_tick(0); |
| 84 | } |
| 85 | |
| 86 | static void bcm47xx_wdt_pause(void) |
| 87 | { |
| 88 | del_timer_sync(&wdt_timer); |
| 89 | bcm47xx_wdt_hw_stop(); |
| 90 | } |
| 91 | |
| 92 | static void bcm47xx_wdt_stop(void) |
| 93 | { |
| 94 | bcm47xx_wdt_pause(); |
| 95 | } |
| 96 | |
| 97 | static int bcm47xx_wdt_settimeout(int new_time) |
| 98 | { |
| 99 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) |
| 100 | return -EINVAL; |
| 101 | |
| 102 | wdt_time = new_time; |
| 103 | return 0; |
| 104 | } |
| 105 | |
| 106 | static int bcm47xx_wdt_open(struct inode *inode, struct file *file) |
| 107 | { |
| 108 | if (test_and_set_bit(0, &bcm47xx_wdt_busy)) |
| 109 | return -EBUSY; |
| 110 | |
| 111 | bcm47xx_wdt_start(); |
| 112 | return nonseekable_open(inode, file); |
| 113 | } |
| 114 | |
| 115 | static int bcm47xx_wdt_release(struct inode *inode, struct file *file) |
| 116 | { |
| 117 | if (expect_release == 42) { |
| 118 | bcm47xx_wdt_stop(); |
| 119 | } else { |
| 120 | printk(KERN_CRIT DRV_NAME |
| 121 | ": Unexpected close, not stopping watchdog!\n"); |
| 122 | bcm47xx_wdt_start(); |
| 123 | } |
| 124 | |
| 125 | clear_bit(0, &bcm47xx_wdt_busy); |
| 126 | expect_release = 0; |
| 127 | return 0; |
| 128 | } |
| 129 | |
| 130 | static ssize_t bcm47xx_wdt_write(struct file *file, const char __user *data, |
| 131 | size_t len, loff_t *ppos) |
| 132 | { |
| 133 | if (len) { |
| 134 | if (!nowayout) { |
| 135 | size_t i; |
| 136 | |
| 137 | expect_release = 0; |
| 138 | |
| 139 | for (i = 0; i != len; i++) { |
| 140 | char c; |
| 141 | if (get_user(c, data + i)) |
| 142 | return -EFAULT; |
| 143 | if (c == 'V') |
| 144 | expect_release = 42; |
| 145 | } |
| 146 | } |
| 147 | bcm47xx_wdt_pet(); |
| 148 | } |
| 149 | return len; |
| 150 | } |
| 151 | |
| 152 | static struct watchdog_info bcm47xx_wdt_info = { |
| 153 | .identity = DRV_NAME, |
| 154 | .options = WDIOF_SETTIMEOUT | |
| 155 | WDIOF_KEEPALIVEPING | |
| 156 | WDIOF_MAGICCLOSE, |
| 157 | }; |
| 158 | |
| 159 | static long bcm47xx_wdt_ioctl(struct file *file, |
| 160 | unsigned int cmd, unsigned long arg) |
| 161 | { |
| 162 | void __user *argp = (void __user *)arg; |
| 163 | int __user *p = argp; |
| 164 | int new_value, retval = -EINVAL;; |
| 165 | |
| 166 | switch (cmd) { |
| 167 | case WDIOC_GETSUPPORT: |
| 168 | return copy_to_user(argp, &bcm47xx_wdt_info, |
| 169 | sizeof(bcm47xx_wdt_info)) ? -EFAULT : 0; |
| 170 | |
| 171 | case WDIOC_GETSTATUS: |
| 172 | case WDIOC_GETBOOTSTATUS: |
| 173 | return put_user(0, p); |
| 174 | |
| 175 | case WDIOC_SETOPTIONS: |
| 176 | if (get_user(new_value, p)) |
| 177 | return -EFAULT; |
| 178 | |
| 179 | if (new_value & WDIOS_DISABLECARD) { |
| 180 | bcm47xx_wdt_stop(); |
| 181 | retval = 0; |
| 182 | } |
| 183 | |
| 184 | if (new_value & WDIOS_ENABLECARD) { |
| 185 | bcm47xx_wdt_start(); |
| 186 | retval = 0; |
| 187 | } |
| 188 | |
| 189 | return retval; |
| 190 | |
| 191 | case WDIOC_KEEPALIVE: |
| 192 | bcm47xx_wdt_pet(); |
| 193 | return 0; |
| 194 | |
| 195 | case WDIOC_SETTIMEOUT: |
| 196 | if (get_user(new_value, p)) |
| 197 | return -EFAULT; |
| 198 | |
| 199 | if (bcm47xx_wdt_settimeout(new_value)) |
| 200 | return -EINVAL; |
| 201 | |
| 202 | bcm47xx_wdt_pet(); |
| 203 | |
| 204 | case WDIOC_GETTIMEOUT: |
| 205 | return put_user(wdt_time, p); |
| 206 | |
| 207 | default: |
| 208 | return -ENOTTY; |
| 209 | } |
| 210 | } |
| 211 | |
| 212 | static int bcm47xx_wdt_notify_sys(struct notifier_block *this, |
| 213 | unsigned long code, void *unused) |
| 214 | { |
| 215 | if (code == SYS_DOWN || code == SYS_HALT) |
| 216 | bcm47xx_wdt_stop(); |
| 217 | return NOTIFY_DONE; |
| 218 | } |
| 219 | |
| 220 | static const struct file_operations bcm47xx_wdt_fops = { |
| 221 | .owner = THIS_MODULE, |
| 222 | .llseek = no_llseek, |
| 223 | .unlocked_ioctl = bcm47xx_wdt_ioctl, |
| 224 | .open = bcm47xx_wdt_open, |
| 225 | .release = bcm47xx_wdt_release, |
| 226 | .write = bcm47xx_wdt_write, |
| 227 | }; |
| 228 | |
| 229 | static struct miscdevice bcm47xx_wdt_miscdev = { |
| 230 | .minor = WATCHDOG_MINOR, |
| 231 | .name = "watchdog", |
| 232 | .fops = &bcm47xx_wdt_fops, |
| 233 | }; |
| 234 | |
| 235 | static struct notifier_block bcm47xx_wdt_notifier = { |
| 236 | .notifier_call = bcm47xx_wdt_notify_sys, |
| 237 | }; |
| 238 | |
| 239 | static int __init bcm47xx_wdt_init(void) |
| 240 | { |
| 241 | int ret; |
| 242 | |
| 243 | if (bcm47xx_wdt_hw_stop() < 0) |
| 244 | return -ENODEV; |
| 245 | |
| 246 | setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L); |
| 247 | |
| 248 | if (bcm47xx_wdt_settimeout(wdt_time)) { |
| 249 | bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME); |
| 250 | printk(KERN_INFO DRV_NAME ": " |
| 251 | "wdt_time value must be 0 < wdt_time < %d, using %d\n", |
| 252 | (WDT_MAX_TIME + 1), wdt_time); |
| 253 | } |
| 254 | |
| 255 | ret = register_reboot_notifier(&bcm47xx_wdt_notifier); |
| 256 | if (ret) |
| 257 | return ret; |
| 258 | |
| 259 | ret = misc_register(&bcm47xx_wdt_miscdev); |
| 260 | if (ret) { |
| 261 | unregister_reboot_notifier(&bcm47xx_wdt_notifier); |
| 262 | return ret; |
| 263 | } |
| 264 | |
| 265 | printk(KERN_INFO "BCM47xx Watchdog Timer enabled (%d seconds%s)\n", |
| 266 | wdt_time, nowayout ? ", nowayout" : ""); |
| 267 | return 0; |
| 268 | } |
| 269 | |
| 270 | static void __exit bcm47xx_wdt_exit(void) |
| 271 | { |
| 272 | if (!nowayout) |
| 273 | bcm47xx_wdt_stop(); |
| 274 | |
| 275 | misc_deregister(&bcm47xx_wdt_miscdev); |
| 276 | |
| 277 | unregister_reboot_notifier(&bcm47xx_wdt_notifier); |
| 278 | } |
| 279 | |
| 280 | module_init(bcm47xx_wdt_init); |
| 281 | module_exit(bcm47xx_wdt_exit); |
| 282 | |
| 283 | MODULE_AUTHOR("Aleksandar Radovanovic"); |
| 284 | MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx"); |
| 285 | MODULE_LICENSE("GPL"); |
| 286 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |