Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Watchdog driver for Atmel AT91RM9200 (Thunder) |
| 3 | * |
| 4 | * Copyright (C) 2003 SAN People (Pty) Ltd |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | */ |
| 11 | |
Jiri Slaby | 1977f03 | 2007-10-18 23:40:25 -0700 | [diff] [blame] | 12 | #include <linux/bitops.h> |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 13 | #include <linux/errno.h> |
| 14 | #include <linux/fs.h> |
| 15 | #include <linux/init.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/miscdevice.h> |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/moduleparam.h> |
Andrew Victor | dfc7bd9 | 2006-05-21 15:32:59 +0200 | [diff] [blame] | 20 | #include <linux/platform_device.h> |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 21 | #include <linux/types.h> |
| 22 | #include <linux/watchdog.h> |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 23 | #include <linux/uaccess.h> |
Andrew Victor | 55d8bae | 2006-11-30 17:16:43 +0100 | [diff] [blame] | 24 | #include <asm/arch/at91_st.h> |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 25 | |
| 26 | |
Andrew Victor | dfc7bd9 | 2006-05-21 15:32:59 +0200 | [diff] [blame] | 27 | #define WDT_DEFAULT_TIME 5 /* seconds */ |
| 28 | #define WDT_MAX_TIME 256 /* seconds */ |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 29 | |
| 30 | static int wdt_time = WDT_DEFAULT_TIME; |
| 31 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 32 | |
| 33 | module_param(wdt_time, int, 0); |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 34 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
| 35 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 36 | |
Andrew Victor | dfc7bd9 | 2006-05-21 15:32:59 +0200 | [diff] [blame] | 37 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 38 | module_param(nowayout, int, 0); |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 39 | MODULE_PARM_DESC(nowayout, |
| 40 | "Watchdog cannot be stopped once started (default=" |
| 41 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
Andrew Victor | dfc7bd9 | 2006-05-21 15:32:59 +0200 | [diff] [blame] | 42 | #endif |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 43 | |
| 44 | |
| 45 | static unsigned long at91wdt_busy; |
| 46 | |
| 47 | /* ......................................................................... */ |
| 48 | |
| 49 | /* |
| 50 | * Disable the watchdog. |
| 51 | */ |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 52 | static inline void at91_wdt_stop(void) |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 53 | { |
| 54 | at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN); |
| 55 | } |
| 56 | |
| 57 | /* |
| 58 | * Enable and reset the watchdog. |
| 59 | */ |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 60 | static inline void at91_wdt_start(void) |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 61 | { |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 62 | at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | |
| 63 | (((65536 * wdt_time) >> 8) & AT91_ST_WDV)); |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 64 | at91_sys_write(AT91_ST_CR, AT91_ST_WDRST); |
| 65 | } |
| 66 | |
| 67 | /* |
| 68 | * Reload the watchdog timer. (ie, pat the watchdog) |
| 69 | */ |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 70 | static inline void at91_wdt_reload(void) |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 71 | { |
| 72 | at91_sys_write(AT91_ST_CR, AT91_ST_WDRST); |
| 73 | } |
| 74 | |
| 75 | /* ......................................................................... */ |
| 76 | |
| 77 | /* |
| 78 | * Watchdog device is opened, and watchdog starts running. |
| 79 | */ |
| 80 | static int at91_wdt_open(struct inode *inode, struct file *file) |
| 81 | { |
| 82 | if (test_and_set_bit(0, &at91wdt_busy)) |
| 83 | return -EBUSY; |
| 84 | |
| 85 | at91_wdt_start(); |
| 86 | return nonseekable_open(inode, file); |
| 87 | } |
| 88 | |
| 89 | /* |
| 90 | * Close the watchdog device. |
| 91 | * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also |
| 92 | * disabled. |
| 93 | */ |
| 94 | static int at91_wdt_close(struct inode *inode, struct file *file) |
| 95 | { |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 96 | /* Disable the watchdog when file is closed */ |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 97 | if (!nowayout) |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 98 | at91_wdt_stop(); |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 99 | |
| 100 | clear_bit(0, &at91wdt_busy); |
| 101 | return 0; |
| 102 | } |
| 103 | |
| 104 | /* |
| 105 | * Change the watchdog time interval. |
| 106 | */ |
| 107 | static int at91_wdt_settimeout(int new_time) |
| 108 | { |
| 109 | /* |
| 110 | * All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz |
| 111 | * |
| 112 | * Since WDV is a 16-bit counter, the maximum period is |
| 113 | * 65536 / 0.256 = 256 seconds. |
| 114 | */ |
| 115 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) |
| 116 | return -EINVAL; |
| 117 | |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 118 | /* Set new watchdog time. It will be used when |
| 119 | at91_wdt_start() is called. */ |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 120 | wdt_time = new_time; |
| 121 | return 0; |
| 122 | } |
| 123 | |
| 124 | static struct watchdog_info at91_wdt_info = { |
| 125 | .identity = "at91 watchdog", |
| 126 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, |
| 127 | }; |
| 128 | |
| 129 | /* |
| 130 | * Handle commands from user-space. |
| 131 | */ |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 132 | static long at91_wdt_ioct(struct file *file, |
| 133 | unsigned int cmd, unsigned long arg) |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 134 | { |
| 135 | void __user *argp = (void __user *)arg; |
| 136 | int __user *p = argp; |
| 137 | int new_value; |
| 138 | |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 139 | switch (cmd) { |
| 140 | case WDIOC_KEEPALIVE: |
| 141 | at91_wdt_reload(); /* pat the watchdog */ |
| 142 | return 0; |
| 143 | case WDIOC_GETSUPPORT: |
| 144 | return copy_to_user(argp, &at91_wdt_info, |
| 145 | sizeof(at91_wdt_info)) ? -EFAULT : 0; |
| 146 | case WDIOC_SETTIMEOUT: |
| 147 | if (get_user(new_value, p)) |
| 148 | return -EFAULT; |
| 149 | if (at91_wdt_settimeout(new_value)) |
| 150 | return -EINVAL; |
| 151 | /* Enable new time value */ |
| 152 | at91_wdt_start(); |
| 153 | /* Return current value */ |
| 154 | return put_user(wdt_time, p); |
| 155 | case WDIOC_GETTIMEOUT: |
| 156 | return put_user(wdt_time, p); |
| 157 | case WDIOC_GETSTATUS: |
| 158 | case WDIOC_GETBOOTSTATUS: |
| 159 | return put_user(0, p); |
| 160 | case WDIOC_SETOPTIONS: |
| 161 | if (get_user(new_value, p)) |
| 162 | return -EFAULT; |
| 163 | if (new_value & WDIOS_DISABLECARD) |
| 164 | at91_wdt_stop(); |
| 165 | if (new_value & WDIOS_ENABLECARD) |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 166 | at91_wdt_start(); |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 167 | return 0; |
| 168 | default: |
| 169 | return -ENOTTY; |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 170 | } |
| 171 | } |
| 172 | |
| 173 | /* |
| 174 | * Pat the watchdog whenever device is written to. |
| 175 | */ |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 176 | static ssize_t at91_wdt_write(struct file *file, const char *data, |
| 177 | size_t len, loff_t *ppos) |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 178 | { |
| 179 | at91_wdt_reload(); /* pat the watchdog */ |
| 180 | return len; |
| 181 | } |
| 182 | |
| 183 | /* ......................................................................... */ |
| 184 | |
Arjan van de Ven | 62322d2 | 2006-07-03 00:24:21 -0700 | [diff] [blame] | 185 | static const struct file_operations at91wdt_fops = { |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 186 | .owner = THIS_MODULE, |
| 187 | .llseek = no_llseek, |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 188 | .unlocked_ioctl = at91_wdt_ioctl, |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 189 | .open = at91_wdt_open, |
| 190 | .release = at91_wdt_close, |
| 191 | .write = at91_wdt_write, |
| 192 | }; |
| 193 | |
| 194 | static struct miscdevice at91wdt_miscdev = { |
| 195 | .minor = WATCHDOG_MINOR, |
| 196 | .name = "watchdog", |
| 197 | .fops = &at91wdt_fops, |
| 198 | }; |
| 199 | |
Andrew Victor | dfc7bd9 | 2006-05-21 15:32:59 +0200 | [diff] [blame] | 200 | static int __init at91wdt_probe(struct platform_device *pdev) |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 201 | { |
| 202 | int res; |
| 203 | |
Andrew Victor | e0b79e0 | 2006-12-04 15:56:18 +0200 | [diff] [blame] | 204 | if (at91wdt_miscdev.parent) |
Andrew Victor | dfc7bd9 | 2006-05-21 15:32:59 +0200 | [diff] [blame] | 205 | return -EBUSY; |
Andrew Victor | e0b79e0 | 2006-12-04 15:56:18 +0200 | [diff] [blame] | 206 | at91wdt_miscdev.parent = &pdev->dev; |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 207 | |
| 208 | res = misc_register(&at91wdt_miscdev); |
| 209 | if (res) |
| 210 | return res; |
| 211 | |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 212 | printk(KERN_INFO "AT91 Watchdog Timer enabled (%d seconds%s)\n", |
| 213 | wdt_time, nowayout ? ", nowayout" : ""); |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 214 | return 0; |
| 215 | } |
| 216 | |
Andrew Victor | dfc7bd9 | 2006-05-21 15:32:59 +0200 | [diff] [blame] | 217 | static int __exit at91wdt_remove(struct platform_device *pdev) |
| 218 | { |
| 219 | int res; |
| 220 | |
| 221 | res = misc_deregister(&at91wdt_miscdev); |
| 222 | if (!res) |
Andrew Victor | e0b79e0 | 2006-12-04 15:56:18 +0200 | [diff] [blame] | 223 | at91wdt_miscdev.parent = NULL; |
Andrew Victor | dfc7bd9 | 2006-05-21 15:32:59 +0200 | [diff] [blame] | 224 | |
| 225 | return res; |
| 226 | } |
| 227 | |
| 228 | static void at91wdt_shutdown(struct platform_device *pdev) |
| 229 | { |
| 230 | at91_wdt_stop(); |
| 231 | } |
| 232 | |
| 233 | #ifdef CONFIG_PM |
| 234 | |
| 235 | static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message) |
| 236 | { |
| 237 | at91_wdt_stop(); |
| 238 | return 0; |
| 239 | } |
| 240 | |
| 241 | static int at91wdt_resume(struct platform_device *pdev) |
| 242 | { |
| 243 | if (at91wdt_busy) |
| 244 | at91_wdt_start(); |
| 245 | return 0; |
| 246 | } |
| 247 | |
| 248 | #else |
| 249 | #define at91wdt_suspend NULL |
| 250 | #define at91wdt_resume NULL |
| 251 | #endif |
| 252 | |
| 253 | static struct platform_driver at91wdt_driver = { |
| 254 | .probe = at91wdt_probe, |
| 255 | .remove = __exit_p(at91wdt_remove), |
| 256 | .shutdown = at91wdt_shutdown, |
| 257 | .suspend = at91wdt_suspend, |
| 258 | .resume = at91wdt_resume, |
| 259 | .driver = { |
| 260 | .name = "at91_wdt", |
| 261 | .owner = THIS_MODULE, |
| 262 | }, |
| 263 | }; |
| 264 | |
| 265 | static int __init at91_wdt_init(void) |
| 266 | { |
Alan Cox | 2760600 | 2008-05-19 14:05:19 +0100 | [diff] [blame] | 267 | /* Check that the heartbeat value is within range; |
| 268 | if not reset to the default */ |
Andrew Victor | dfc7bd9 | 2006-05-21 15:32:59 +0200 | [diff] [blame] | 269 | if (at91_wdt_settimeout(wdt_time)) { |
| 270 | at91_wdt_settimeout(WDT_DEFAULT_TIME); |
| 271 | pr_info("at91_wdt: wdt_time value must be 1 <= wdt_time <= 256, using %d\n", wdt_time); |
| 272 | } |
| 273 | |
| 274 | return platform_driver_register(&at91wdt_driver); |
| 275 | } |
| 276 | |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 277 | static void __exit at91_wdt_exit(void) |
| 278 | { |
Andrew Victor | dfc7bd9 | 2006-05-21 15:32:59 +0200 | [diff] [blame] | 279 | platform_driver_unregister(&at91wdt_driver); |
Andrew Victor | 853807f | 2006-03-14 11:11:04 +0200 | [diff] [blame] | 280 | } |
| 281 | |
| 282 | module_init(at91_wdt_init); |
| 283 | module_exit(at91_wdt_exit); |
| 284 | |
| 285 | MODULE_AUTHOR("Andrew Victor"); |
| 286 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200"); |
| 287 | MODULE_LICENSE("GPL"); |
| 288 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
Kay Sievers | f37d193 | 2008-04-10 21:29:23 -0700 | [diff] [blame] | 289 | MODULE_ALIAS("platform:at91_wdt"); |