Jordan Crouse | 0b36086 | 2008-01-21 10:07:00 -0700 | [diff] [blame^] | 1 | /* Watchdog timer for the Geode GX/LX with the CS5535/CS5536 companion chip |
| 2 | * |
| 3 | * Copyright (C) 2006-2007, Advanced Micro Devices, Inc. |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU General Public License |
| 7 | * as published by the Free Software Foundation; either version |
| 8 | * 2 of the License, or (at your option) any later version. |
| 9 | */ |
| 10 | |
| 11 | |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/moduleparam.h> |
| 14 | #include <linux/types.h> |
| 15 | #include <linux/miscdevice.h> |
| 16 | #include <linux/watchdog.h> |
| 17 | #include <linux/fs.h> |
| 18 | #include <linux/platform_device.h> |
| 19 | #include <linux/reboot.h> |
| 20 | |
| 21 | #include <asm/uaccess.h> |
| 22 | #include <asm/geode.h> |
| 23 | |
| 24 | #define GEODEWDT_HZ 500 |
| 25 | #define GEODEWDT_SCALE 6 |
| 26 | #define GEODEWDT_MAX_SECONDS 131 |
| 27 | |
| 28 | #define WDT_FLAGS_OPEN 1 |
| 29 | #define WDT_FLAGS_ORPHAN 2 |
| 30 | |
| 31 | #define DRV_NAME "geodewdt" |
| 32 | #define WATCHDOG_NAME "Geode GX/LX WDT" |
| 33 | #define WATCHDOG_TIMEOUT 60 |
| 34 | |
| 35 | static int timeout = WATCHDOG_TIMEOUT; |
| 36 | module_param(timeout, int, 0); |
| 37 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=131, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) "."); |
| 38 | |
| 39 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 40 | module_param(nowayout, int, 0); |
| 41 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 42 | |
| 43 | static struct platform_device *geodewdt_platform_device; |
| 44 | static unsigned long wdt_flags; |
| 45 | static int wdt_timer; |
| 46 | static int safe_close; |
| 47 | |
| 48 | static void geodewdt_ping(void) |
| 49 | { |
| 50 | /* Stop the counter */ |
| 51 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); |
| 52 | |
| 53 | /* Reset the counter */ |
| 54 | geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); |
| 55 | |
| 56 | /* Enable the counter */ |
| 57 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN); |
| 58 | } |
| 59 | |
| 60 | static void geodewdt_disable(void) |
| 61 | { |
| 62 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); |
| 63 | geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); |
| 64 | } |
| 65 | |
| 66 | static int geodewdt_set_heartbeat(int val) |
| 67 | { |
| 68 | if (val < 1 || val > GEODEWDT_MAX_SECONDS) |
| 69 | return -EINVAL; |
| 70 | |
| 71 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); |
| 72 | geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ); |
| 73 | geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); |
| 74 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN); |
| 75 | |
| 76 | timeout = val; |
| 77 | return 0; |
| 78 | } |
| 79 | |
| 80 | static int |
| 81 | geodewdt_open(struct inode *inode, struct file *file) |
| 82 | { |
| 83 | if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags)) |
| 84 | return -EBUSY; |
| 85 | |
| 86 | if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags)) |
| 87 | __module_get(THIS_MODULE); |
| 88 | |
| 89 | geodewdt_ping(); |
| 90 | return nonseekable_open(inode, file); |
| 91 | } |
| 92 | |
| 93 | static int |
| 94 | geodewdt_release(struct inode *inode, struct file *file) |
| 95 | { |
| 96 | if (safe_close) { |
| 97 | geodewdt_disable(); |
| 98 | module_put(THIS_MODULE); |
| 99 | } |
| 100 | else { |
| 101 | printk(KERN_CRIT "Unexpected close - watchdog is not stopping.\n"); |
| 102 | geodewdt_ping(); |
| 103 | |
| 104 | set_bit(WDT_FLAGS_ORPHAN, &wdt_flags); |
| 105 | } |
| 106 | |
| 107 | clear_bit(WDT_FLAGS_OPEN, &wdt_flags); |
| 108 | safe_close = 0; |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | static ssize_t |
| 113 | geodewdt_write(struct file *file, const char __user *data, size_t len, |
| 114 | loff_t *ppos) |
| 115 | { |
| 116 | if(len) { |
| 117 | if (!nowayout) { |
| 118 | size_t i; |
| 119 | safe_close = 0; |
| 120 | |
| 121 | for (i = 0; i != len; i++) { |
| 122 | char c; |
| 123 | |
| 124 | if (get_user(c, data + i)) |
| 125 | return -EFAULT; |
| 126 | |
| 127 | if (c == 'V') |
| 128 | safe_close = 1; |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | geodewdt_ping(); |
| 133 | } |
| 134 | return len; |
| 135 | } |
| 136 | |
| 137 | static int |
| 138 | geodewdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, |
| 139 | unsigned long arg) |
| 140 | { |
| 141 | void __user *argp = (void __user *)arg; |
| 142 | int __user *p = argp; |
| 143 | int interval; |
| 144 | |
| 145 | static struct watchdog_info ident = { |
| 146 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
| 147 | | WDIOF_MAGICCLOSE, |
| 148 | .firmware_version = 1, |
| 149 | .identity = WATCHDOG_NAME, |
| 150 | }; |
| 151 | |
| 152 | switch(cmd) { |
| 153 | case WDIOC_GETSUPPORT: |
| 154 | return copy_to_user(argp, &ident, |
| 155 | sizeof(ident)) ? -EFAULT : 0; |
| 156 | break; |
| 157 | |
| 158 | case WDIOC_GETSTATUS: |
| 159 | case WDIOC_GETBOOTSTATUS: |
| 160 | return put_user(0, p); |
| 161 | |
| 162 | case WDIOC_KEEPALIVE: |
| 163 | geodewdt_ping(); |
| 164 | return 0; |
| 165 | |
| 166 | case WDIOC_SETTIMEOUT: |
| 167 | if (get_user(interval, p)) |
| 168 | return -EFAULT; |
| 169 | |
| 170 | if (geodewdt_set_heartbeat(interval)) |
| 171 | return -EINVAL; |
| 172 | |
| 173 | /* Fall through */ |
| 174 | |
| 175 | case WDIOC_GETTIMEOUT: |
| 176 | return put_user(timeout, p); |
| 177 | |
| 178 | case WDIOC_SETOPTIONS: |
| 179 | { |
| 180 | int options, ret = -EINVAL; |
| 181 | |
| 182 | if (get_user(options, p)) |
| 183 | return -EFAULT; |
| 184 | |
| 185 | if (options & WDIOS_DISABLECARD) { |
| 186 | geodewdt_disable(); |
| 187 | ret = 0; |
| 188 | } |
| 189 | |
| 190 | if (options & WDIOS_ENABLECARD) { |
| 191 | geodewdt_ping(); |
| 192 | ret = 0; |
| 193 | } |
| 194 | |
| 195 | return ret; |
| 196 | } |
| 197 | default: |
| 198 | return -ENOTTY; |
| 199 | } |
| 200 | |
| 201 | return 0; |
| 202 | } |
| 203 | |
| 204 | static const struct file_operations geodewdt_fops = { |
| 205 | .owner = THIS_MODULE, |
| 206 | .llseek = no_llseek, |
| 207 | .write = geodewdt_write, |
| 208 | .ioctl = geodewdt_ioctl, |
| 209 | .open = geodewdt_open, |
| 210 | .release = geodewdt_release, |
| 211 | }; |
| 212 | |
| 213 | static struct miscdevice geodewdt_miscdev = { |
| 214 | .minor = WATCHDOG_MINOR, |
| 215 | .name = "watchdog", |
| 216 | .fops = &geodewdt_fops |
| 217 | }; |
| 218 | |
| 219 | static int __devinit |
| 220 | geodewdt_probe(struct platform_device *dev) |
| 221 | { |
| 222 | int ret, timer; |
| 223 | |
| 224 | timer = geode_mfgpt_alloc_timer(MFGPT_TIMER_ANY, |
| 225 | MFGPT_DOMAIN_WORKING, THIS_MODULE); |
| 226 | |
| 227 | if (timer == -1) { |
| 228 | printk(KERN_ERR "geodewdt: No timers were available\n"); |
| 229 | return -ENODEV; |
| 230 | } |
| 231 | |
| 232 | wdt_timer = timer; |
| 233 | |
| 234 | /* Set up the timer */ |
| 235 | |
| 236 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, |
| 237 | GEODEWDT_SCALE | (3 << 8)); |
| 238 | |
| 239 | /* Set up comparator 2 to reset when the event fires */ |
| 240 | geode_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1); |
| 241 | |
| 242 | /* Set up the initial timeout */ |
| 243 | |
| 244 | geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, |
| 245 | timeout * GEODEWDT_HZ); |
| 246 | |
| 247 | ret = misc_register(&geodewdt_miscdev); |
| 248 | |
| 249 | return ret; |
| 250 | } |
| 251 | |
| 252 | static int __devexit |
| 253 | geodewdt_remove(struct platform_device *dev) |
| 254 | { |
| 255 | misc_deregister(&geodewdt_miscdev); |
| 256 | return 0; |
| 257 | } |
| 258 | |
| 259 | static void |
| 260 | geodewdt_shutdown(struct platform_device *dev) |
| 261 | { |
| 262 | geodewdt_disable(); |
| 263 | } |
| 264 | |
| 265 | static struct platform_driver geodewdt_driver = { |
| 266 | .probe = geodewdt_probe, |
| 267 | .remove = __devexit_p(geodewdt_remove), |
| 268 | .shutdown = geodewdt_shutdown, |
| 269 | .driver = { |
| 270 | .owner = THIS_MODULE, |
| 271 | .name = DRV_NAME, |
| 272 | }, |
| 273 | }; |
| 274 | |
| 275 | static int __init |
| 276 | geodewdt_init(void) |
| 277 | { |
| 278 | int ret; |
| 279 | |
| 280 | ret = platform_driver_register(&geodewdt_driver); |
| 281 | if (ret) |
| 282 | return ret; |
| 283 | |
| 284 | geodewdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0); |
| 285 | if (IS_ERR(geodewdt_platform_device)) { |
| 286 | ret = PTR_ERR(geodewdt_platform_device); |
| 287 | goto err; |
| 288 | } |
| 289 | |
| 290 | return 0; |
| 291 | err: |
| 292 | platform_driver_unregister(&geodewdt_driver); |
| 293 | return ret; |
| 294 | } |
| 295 | |
| 296 | static void __exit |
| 297 | geodewdt_exit(void) |
| 298 | { |
| 299 | platform_device_unregister(geodewdt_platform_device); |
| 300 | platform_driver_unregister(&geodewdt_driver); |
| 301 | } |
| 302 | |
| 303 | module_init(geodewdt_init); |
| 304 | module_exit(geodewdt_exit); |
| 305 | |
| 306 | MODULE_AUTHOR("Advanced Micro Devices, Inc"); |
| 307 | MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver"); |
| 308 | MODULE_LICENSE("GPL"); |
| 309 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |