Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Watchdog driver for the mpcore watchdog timer |
| 3 | * |
| 4 | * (c) Copyright 2004 ARM Limited |
| 5 | * |
| 6 | * Based on the SoftDog driver: |
| 7 | * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. |
| 8 | * http://www.redhat.com |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or |
| 11 | * modify it under the terms of the GNU General Public License |
| 12 | * as published by the Free Software Foundation; either version |
| 13 | * 2 of the License, or (at your option) any later version. |
| 14 | * |
| 15 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
| 16 | * warranty for any of this software. This material is provided |
| 17 | * "AS-IS" and at no charge. |
| 18 | * |
| 19 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> |
| 20 | * |
| 21 | */ |
| 22 | #include <linux/module.h> |
| 23 | #include <linux/moduleparam.h> |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 24 | #include <linux/types.h> |
| 25 | #include <linux/miscdevice.h> |
| 26 | #include <linux/watchdog.h> |
| 27 | #include <linux/fs.h> |
| 28 | #include <linux/reboot.h> |
| 29 | #include <linux/init.h> |
| 30 | #include <linux/interrupt.h> |
Russell King | d052d1b | 2005-10-29 19:07:23 +0100 | [diff] [blame] | 31 | #include <linux/platform_device.h> |
Russell King | ad4162f | 2005-09-14 09:56:38 +0100 | [diff] [blame] | 32 | |
| 33 | #include <asm/hardware/arm_twd.h> |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 34 | #include <asm/uaccess.h> |
| 35 | |
| 36 | struct mpcore_wdt { |
| 37 | unsigned long timer_alive; |
| 38 | struct device *dev; |
| 39 | void __iomem *base; |
| 40 | int irq; |
| 41 | unsigned int perturb; |
| 42 | char expect_close; |
| 43 | }; |
| 44 | |
| 45 | static struct platform_device *mpcore_wdt_dev; |
| 46 | |
| 47 | extern unsigned int mpcore_timer_rate; |
| 48 | |
| 49 | #define TIMER_MARGIN 60 |
| 50 | static int mpcore_margin = TIMER_MARGIN; |
| 51 | module_param(mpcore_margin, int, 0); |
| 52 | MODULE_PARM_DESC(mpcore_margin, "MPcore timer margin in seconds. (0<mpcore_margin<65536, default=" __MODULE_STRING(TIMER_MARGIN) ")"); |
| 53 | |
| 54 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 55 | module_param(nowayout, int, 0); |
| 56 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 57 | |
| 58 | #define ONLY_TESTING 0 |
| 59 | static int mpcore_noboot = ONLY_TESTING; |
| 60 | module_param(mpcore_noboot, int, 0); |
| 61 | MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, set to 1 to ignore reboots, 0 to reboot (default=" __MODULE_STRING(ONLY_TESTING) ")"); |
| 62 | |
| 63 | /* |
| 64 | * This is the interrupt handler. Note that we only use this |
| 65 | * in testing mode, so don't actually do a reboot here. |
| 66 | */ |
| 67 | static irqreturn_t mpcore_wdt_fire(int irq, void *arg, struct pt_regs *regs) |
| 68 | { |
| 69 | struct mpcore_wdt *wdt = arg; |
| 70 | |
| 71 | /* Check it really was our interrupt */ |
| 72 | if (readl(wdt->base + TWD_WDOG_INTSTAT)) { |
| 73 | dev_printk(KERN_CRIT, wdt->dev, "Triggered - Reboot ignored.\n"); |
| 74 | |
| 75 | /* Clear the interrupt on the watchdog */ |
| 76 | writel(1, wdt->base + TWD_WDOG_INTSTAT); |
| 77 | |
| 78 | return IRQ_HANDLED; |
| 79 | } |
| 80 | |
| 81 | return IRQ_NONE; |
| 82 | } |
| 83 | |
| 84 | /* |
| 85 | * mpcore_wdt_keepalive - reload the timer |
| 86 | * |
| 87 | * Note that the spec says a DIFFERENT value must be written to the reload |
| 88 | * register each time. The "perturb" variable deals with this by adding 1 |
| 89 | * to the count every other time the function is called. |
| 90 | */ |
| 91 | static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt) |
| 92 | { |
| 93 | unsigned int count; |
| 94 | |
| 95 | /* Assume prescale is set to 256 */ |
| 96 | count = (mpcore_timer_rate / 256) * mpcore_margin; |
| 97 | |
| 98 | /* Reload the counter */ |
| 99 | writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD); |
| 100 | |
| 101 | wdt->perturb = wdt->perturb ? 0 : 1; |
| 102 | } |
| 103 | |
| 104 | static void mpcore_wdt_stop(struct mpcore_wdt *wdt) |
| 105 | { |
| 106 | writel(0x12345678, wdt->base + TWD_WDOG_DISABLE); |
| 107 | writel(0x87654321, wdt->base + TWD_WDOG_DISABLE); |
| 108 | writel(0x0, wdt->base + TWD_WDOG_CONTROL); |
| 109 | } |
| 110 | |
| 111 | static void mpcore_wdt_start(struct mpcore_wdt *wdt) |
| 112 | { |
| 113 | dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n"); |
| 114 | |
| 115 | /* This loads the count register but does NOT start the count yet */ |
| 116 | mpcore_wdt_keepalive(wdt); |
| 117 | |
| 118 | if (mpcore_noboot) { |
| 119 | /* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */ |
| 120 | writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL); |
| 121 | } else { |
| 122 | /* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */ |
| 123 | writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL); |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | static int mpcore_wdt_set_heartbeat(int t) |
| 128 | { |
| 129 | if (t < 0x0001 || t > 0xFFFF) |
| 130 | return -EINVAL; |
| 131 | |
| 132 | mpcore_margin = t; |
| 133 | return 0; |
| 134 | } |
| 135 | |
| 136 | /* |
| 137 | * /dev/watchdog handling |
| 138 | */ |
| 139 | static int mpcore_wdt_open(struct inode *inode, struct file *file) |
| 140 | { |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 141 | struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_dev); |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 142 | |
| 143 | if (test_and_set_bit(0, &wdt->timer_alive)) |
| 144 | return -EBUSY; |
| 145 | |
| 146 | if (nowayout) |
| 147 | __module_get(THIS_MODULE); |
| 148 | |
| 149 | file->private_data = wdt; |
| 150 | |
| 151 | /* |
| 152 | * Activate timer |
| 153 | */ |
| 154 | mpcore_wdt_start(wdt); |
| 155 | |
| 156 | return nonseekable_open(inode, file); |
| 157 | } |
| 158 | |
| 159 | static int mpcore_wdt_release(struct inode *inode, struct file *file) |
| 160 | { |
| 161 | struct mpcore_wdt *wdt = file->private_data; |
| 162 | |
| 163 | /* |
| 164 | * Shut off the timer. |
| 165 | * Lock it in if it's a module and we set nowayout |
| 166 | */ |
| 167 | if (wdt->expect_close == 42) { |
| 168 | mpcore_wdt_stop(wdt); |
| 169 | } else { |
| 170 | dev_printk(KERN_CRIT, wdt->dev, "unexpected close, not stopping watchdog!\n"); |
| 171 | mpcore_wdt_keepalive(wdt); |
| 172 | } |
| 173 | clear_bit(0, &wdt->timer_alive); |
| 174 | wdt->expect_close = 0; |
| 175 | return 0; |
| 176 | } |
| 177 | |
| 178 | static ssize_t mpcore_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) |
| 179 | { |
| 180 | struct mpcore_wdt *wdt = file->private_data; |
| 181 | |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 182 | /* |
| 183 | * Refresh the timer. |
| 184 | */ |
| 185 | if (len) { |
| 186 | if (!nowayout) { |
| 187 | size_t i; |
| 188 | |
| 189 | /* In case it was set long ago */ |
| 190 | wdt->expect_close = 0; |
| 191 | |
| 192 | for (i = 0; i != len; i++) { |
| 193 | char c; |
| 194 | |
| 195 | if (get_user(c, data + i)) |
| 196 | return -EFAULT; |
| 197 | if (c == 'V') |
| 198 | wdt->expect_close = 42; |
| 199 | } |
| 200 | } |
| 201 | mpcore_wdt_keepalive(wdt); |
| 202 | } |
| 203 | return len; |
| 204 | } |
| 205 | |
| 206 | static struct watchdog_info ident = { |
| 207 | .options = WDIOF_SETTIMEOUT | |
| 208 | WDIOF_KEEPALIVEPING | |
| 209 | WDIOF_MAGICCLOSE, |
| 210 | .identity = "MPcore Watchdog", |
| 211 | }; |
| 212 | |
| 213 | static int mpcore_wdt_ioctl(struct inode *inode, struct file *file, |
| 214 | unsigned int cmd, unsigned long arg) |
| 215 | { |
| 216 | struct mpcore_wdt *wdt = file->private_data; |
| 217 | int ret; |
| 218 | union { |
| 219 | struct watchdog_info ident; |
| 220 | int i; |
| 221 | } uarg; |
| 222 | |
| 223 | if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg)) |
| 224 | return -ENOIOCTLCMD; |
| 225 | |
| 226 | if (_IOC_DIR(cmd) & _IOC_WRITE) { |
| 227 | ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd)); |
| 228 | if (ret) |
| 229 | return -EFAULT; |
| 230 | } |
| 231 | |
| 232 | switch (cmd) { |
| 233 | case WDIOC_GETSUPPORT: |
| 234 | uarg.ident = ident; |
| 235 | ret = 0; |
| 236 | break; |
| 237 | |
| 238 | case WDIOC_SETOPTIONS: |
| 239 | ret = -EINVAL; |
| 240 | if (uarg.i & WDIOS_DISABLECARD) { |
| 241 | mpcore_wdt_stop(wdt); |
| 242 | ret = 0; |
| 243 | } |
| 244 | if (uarg.i & WDIOS_ENABLECARD) { |
| 245 | mpcore_wdt_start(wdt); |
| 246 | ret = 0; |
| 247 | } |
| 248 | break; |
| 249 | |
| 250 | case WDIOC_GETSTATUS: |
| 251 | case WDIOC_GETBOOTSTATUS: |
| 252 | uarg.i = 0; |
| 253 | ret = 0; |
| 254 | break; |
| 255 | |
| 256 | case WDIOC_KEEPALIVE: |
| 257 | mpcore_wdt_keepalive(wdt); |
| 258 | ret = 0; |
| 259 | break; |
| 260 | |
| 261 | case WDIOC_SETTIMEOUT: |
| 262 | ret = mpcore_wdt_set_heartbeat(uarg.i); |
| 263 | if (ret) |
| 264 | break; |
| 265 | |
| 266 | mpcore_wdt_keepalive(wdt); |
| 267 | /* Fall */ |
| 268 | case WDIOC_GETTIMEOUT: |
| 269 | uarg.i = mpcore_margin; |
| 270 | ret = 0; |
| 271 | break; |
| 272 | |
| 273 | default: |
| 274 | return -ENOIOCTLCMD; |
| 275 | } |
| 276 | |
| 277 | if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) { |
| 278 | ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd)); |
| 279 | if (ret) |
| 280 | ret = -EFAULT; |
| 281 | } |
| 282 | return ret; |
| 283 | } |
| 284 | |
| 285 | /* |
| 286 | * System shutdown handler. Turn off the watchdog if we're |
| 287 | * restarting or halting the system. |
| 288 | */ |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 289 | static void mpcore_wdt_shutdown(struct platform_device *dev) |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 290 | { |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 291 | struct mpcore_wdt *wdt = platform_get_drvdata(dev); |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 292 | |
| 293 | if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT) |
| 294 | mpcore_wdt_stop(wdt); |
| 295 | } |
| 296 | |
| 297 | /* |
| 298 | * Kernel Interfaces |
| 299 | */ |
| 300 | static struct file_operations mpcore_wdt_fops = { |
| 301 | .owner = THIS_MODULE, |
| 302 | .llseek = no_llseek, |
| 303 | .write = mpcore_wdt_write, |
| 304 | .ioctl = mpcore_wdt_ioctl, |
| 305 | .open = mpcore_wdt_open, |
| 306 | .release = mpcore_wdt_release, |
| 307 | }; |
| 308 | |
| 309 | static struct miscdevice mpcore_wdt_miscdev = { |
| 310 | .minor = WATCHDOG_MINOR, |
| 311 | .name = "watchdog", |
| 312 | .fops = &mpcore_wdt_fops, |
| 313 | }; |
| 314 | |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 315 | static int __devinit mpcore_wdt_probe(struct platform_device *dev) |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 316 | { |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 317 | struct mpcore_wdt *wdt; |
| 318 | struct resource *res; |
| 319 | int ret; |
| 320 | |
| 321 | /* We only accept one device, and it must have an id of -1 */ |
| 322 | if (dev->id != -1) |
| 323 | return -ENODEV; |
| 324 | |
| 325 | res = platform_get_resource(dev, IORESOURCE_MEM, 0); |
| 326 | if (!res) { |
| 327 | ret = -ENODEV; |
| 328 | goto err_out; |
| 329 | } |
| 330 | |
| 331 | wdt = kmalloc(sizeof(struct mpcore_wdt), GFP_KERNEL); |
| 332 | if (!wdt) { |
| 333 | ret = -ENOMEM; |
| 334 | goto err_out; |
| 335 | } |
| 336 | memset(wdt, 0, sizeof(struct mpcore_wdt)); |
| 337 | |
| 338 | wdt->dev = &dev->dev; |
| 339 | wdt->irq = platform_get_irq(dev, 0); |
David Vrabel | 4894473 | 2006-01-19 17:56:29 +0000 | [diff] [blame] | 340 | if (wdt->irq < 0) { |
| 341 | ret = -ENXIO; |
| 342 | goto err_free; |
| 343 | } |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 344 | wdt->base = ioremap(res->start, res->end - res->start + 1); |
| 345 | if (!wdt->base) { |
| 346 | ret = -ENOMEM; |
| 347 | goto err_free; |
| 348 | } |
| 349 | |
| 350 | mpcore_wdt_miscdev.dev = &dev->dev; |
| 351 | ret = misc_register(&mpcore_wdt_miscdev); |
| 352 | if (ret) { |
| 353 | dev_printk(KERN_ERR, _dev, "cannot register miscdev on minor=%d (err=%d)\n", |
| 354 | WATCHDOG_MINOR, ret); |
| 355 | goto err_misc; |
| 356 | } |
| 357 | |
Thomas Gleixner | 0f2ed4c | 2006-07-01 19:29:33 -0700 | [diff] [blame^] | 358 | ret = request_irq(wdt->irq, mpcore_wdt_fire, IRQF_DISABLED, "mpcore_wdt", wdt); |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 359 | if (ret) { |
| 360 | dev_printk(KERN_ERR, _dev, "cannot register IRQ%d for watchdog\n", wdt->irq); |
| 361 | goto err_irq; |
| 362 | } |
| 363 | |
| 364 | mpcore_wdt_stop(wdt); |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 365 | platform_set_drvdata(&dev->dev, wdt); |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 366 | mpcore_wdt_dev = dev; |
| 367 | |
| 368 | return 0; |
| 369 | |
| 370 | err_irq: |
| 371 | misc_deregister(&mpcore_wdt_miscdev); |
| 372 | err_misc: |
| 373 | iounmap(wdt->base); |
| 374 | err_free: |
| 375 | kfree(wdt); |
| 376 | err_out: |
| 377 | return ret; |
| 378 | } |
| 379 | |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 380 | static int __devexit mpcore_wdt_remove(struct platform_device *dev) |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 381 | { |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 382 | struct mpcore_wdt *wdt = platform_get_drvdata(dev); |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 383 | |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 384 | platform_set_drvdata(dev, NULL); |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 385 | |
| 386 | misc_deregister(&mpcore_wdt_miscdev); |
| 387 | |
| 388 | mpcore_wdt_dev = NULL; |
| 389 | |
| 390 | free_irq(wdt->irq, wdt); |
| 391 | iounmap(wdt->base); |
| 392 | kfree(wdt); |
| 393 | return 0; |
| 394 | } |
| 395 | |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 396 | static struct platform_driver mpcore_wdt_driver = { |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 397 | .probe = mpcore_wdt_probe, |
| 398 | .remove = __devexit_p(mpcore_wdt_remove), |
| 399 | .shutdown = mpcore_wdt_shutdown, |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 400 | .driver = { |
| 401 | .owner = THIS_MODULE, |
| 402 | .name = "mpcore_wdt", |
| 403 | }, |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 404 | }; |
| 405 | |
| 406 | static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n"; |
| 407 | |
| 408 | static int __init mpcore_wdt_init(void) |
| 409 | { |
| 410 | /* |
| 411 | * Check that the margin value is within it's range; |
| 412 | * if not reset to the default |
| 413 | */ |
| 414 | if (mpcore_wdt_set_heartbeat(mpcore_margin)) { |
| 415 | mpcore_wdt_set_heartbeat(TIMER_MARGIN); |
| 416 | printk(KERN_INFO "mpcore_margin value must be 0<mpcore_margin<65536, using %d\n", |
| 417 | TIMER_MARGIN); |
| 418 | } |
| 419 | |
| 420 | printk(banner, mpcore_noboot, mpcore_margin, nowayout); |
| 421 | |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 422 | return platform_driver_register(&mpcore_wdt_driver); |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 423 | } |
| 424 | |
| 425 | static void __exit mpcore_wdt_exit(void) |
| 426 | { |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 427 | platform_driver_unregister(&mpcore_wdt_driver); |
Russell King | b9d36b8 | 2005-09-12 22:56:56 +0100 | [diff] [blame] | 428 | } |
| 429 | |
| 430 | module_init(mpcore_wdt_init); |
| 431 | module_exit(mpcore_wdt_exit); |
| 432 | |
| 433 | MODULE_AUTHOR("ARM Limited"); |
| 434 | MODULE_DESCRIPTION("MPcore Watchdog Device Driver"); |
| 435 | MODULE_LICENSE("GPL"); |
| 436 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |