Daniel Mentz | 94787a1 | 2013-05-29 21:12:04 -0700 | [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@lxorguk.ukuu.org.uk>, |
| 8 | * All Rights Reserved. |
| 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> |
| 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> |
| 31 | #include <linux/platform_device.h> |
| 32 | #include <linux/uaccess.h> |
| 33 | #include <linux/slab.h> |
| 34 | #include <linux/io.h> |
| 35 | |
| 36 | #include <asm/smp_twd.h> |
| 37 | |
| 38 | struct mpcore_wdt { |
| 39 | unsigned long timer_alive; |
| 40 | struct device *dev; |
| 41 | void __iomem *base; |
| 42 | int irq; |
| 43 | unsigned int perturb; |
| 44 | char expect_close; |
| 45 | }; |
| 46 | |
| 47 | static struct platform_device *mpcore_wdt_dev; |
| 48 | static DEFINE_SPINLOCK(wdt_lock); |
| 49 | |
| 50 | #define TIMER_MARGIN 60 |
| 51 | static int mpcore_margin = TIMER_MARGIN; |
| 52 | module_param(mpcore_margin, int, 0); |
| 53 | MODULE_PARM_DESC(mpcore_margin, |
| 54 | "MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default=" |
| 55 | __MODULE_STRING(TIMER_MARGIN) ")"); |
| 56 | |
| 57 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 58 | module_param(nowayout, int, 0); |
| 59 | MODULE_PARM_DESC(nowayout, |
| 60 | "Watchdog cannot be stopped once started (default=" |
| 61 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 62 | |
| 63 | #define ONLY_TESTING 0 |
| 64 | static int mpcore_noboot = ONLY_TESTING; |
| 65 | module_param(mpcore_noboot, int, 0); |
| 66 | MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, " |
| 67 | "set to 1 to ignore reboots, 0 to reboot (default=" |
| 68 | __MODULE_STRING(ONLY_TESTING) ")"); |
| 69 | |
| 70 | /* |
| 71 | * This is the interrupt handler. Note that we only use this |
| 72 | * in testing mode, so don't actually do a reboot here. |
| 73 | */ |
| 74 | static irqreturn_t mpcore_wdt_fire(int irq, void *arg) |
| 75 | { |
| 76 | struct mpcore_wdt *wdt = arg; |
| 77 | |
| 78 | /* Check it really was our interrupt */ |
| 79 | if (readl(wdt->base + TWD_WDOG_INTSTAT)) { |
| 80 | dev_printk(KERN_CRIT, wdt->dev, |
| 81 | "Triggered - Reboot ignored.\n"); |
| 82 | /* Clear the interrupt on the watchdog */ |
| 83 | writel(1, wdt->base + TWD_WDOG_INTSTAT); |
| 84 | return IRQ_HANDLED; |
| 85 | } |
| 86 | return IRQ_NONE; |
| 87 | } |
| 88 | |
| 89 | /* |
| 90 | * mpcore_wdt_keepalive - reload the timer |
| 91 | * |
| 92 | * Note that the spec says a DIFFERENT value must be written to the reload |
| 93 | * register each time. The "perturb" variable deals with this by adding 1 |
| 94 | * to the count every other time the function is called. |
| 95 | */ |
| 96 | static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt) |
| 97 | { |
| 98 | unsigned long count; |
| 99 | |
| 100 | spin_lock(&wdt_lock); |
| 101 | /* Assume prescale is set to 256 */ |
| 102 | count = __raw_readl(wdt->base + TWD_WDOG_COUNTER); |
| 103 | count = (0xFFFFFFFFU - count) * (HZ / 5); |
| 104 | count = (count / 256) * mpcore_margin; |
| 105 | |
| 106 | /* Reload the counter */ |
| 107 | writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD); |
| 108 | wdt->perturb = wdt->perturb ? 0 : 1; |
| 109 | spin_unlock(&wdt_lock); |
| 110 | } |
| 111 | |
| 112 | static void mpcore_wdt_stop(struct mpcore_wdt *wdt) |
| 113 | { |
| 114 | spin_lock(&wdt_lock); |
| 115 | writel(0x12345678, wdt->base + TWD_WDOG_DISABLE); |
| 116 | writel(0x87654321, wdt->base + TWD_WDOG_DISABLE); |
| 117 | writel(0x0, wdt->base + TWD_WDOG_CONTROL); |
| 118 | spin_unlock(&wdt_lock); |
| 119 | } |
| 120 | |
| 121 | static void mpcore_wdt_start(struct mpcore_wdt *wdt) |
| 122 | { |
| 123 | dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n"); |
| 124 | |
| 125 | /* This loads the count register but does NOT start the count yet */ |
| 126 | mpcore_wdt_keepalive(wdt); |
| 127 | |
| 128 | if (mpcore_noboot) { |
| 129 | /* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */ |
| 130 | writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL); |
| 131 | } else { |
| 132 | /* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */ |
| 133 | writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL); |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | static int mpcore_wdt_set_heartbeat(int t) |
| 138 | { |
| 139 | if (t < 0x0001 || t > 0xFFFF) |
| 140 | return -EINVAL; |
| 141 | |
| 142 | mpcore_margin = t; |
| 143 | return 0; |
| 144 | } |
| 145 | |
| 146 | /* |
| 147 | * /dev/watchdog handling |
| 148 | */ |
| 149 | static int mpcore_wdt_open(struct inode *inode, struct file *file) |
| 150 | { |
| 151 | struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_dev); |
| 152 | |
| 153 | if (test_and_set_bit(0, &wdt->timer_alive)) |
| 154 | return -EBUSY; |
| 155 | |
| 156 | if (nowayout) |
| 157 | __module_get(THIS_MODULE); |
| 158 | |
| 159 | file->private_data = wdt; |
| 160 | |
| 161 | /* |
| 162 | * Activate timer |
| 163 | */ |
| 164 | mpcore_wdt_start(wdt); |
| 165 | |
| 166 | return nonseekable_open(inode, file); |
| 167 | } |
| 168 | |
| 169 | static int mpcore_wdt_release(struct inode *inode, struct file *file) |
| 170 | { |
| 171 | struct mpcore_wdt *wdt = file->private_data; |
| 172 | |
| 173 | /* |
| 174 | * Shut off the timer. |
| 175 | * Lock it in if it's a module and we set nowayout |
| 176 | */ |
| 177 | if (wdt->expect_close == 42) |
| 178 | mpcore_wdt_stop(wdt); |
| 179 | else { |
| 180 | dev_printk(KERN_CRIT, wdt->dev, |
| 181 | "unexpected close, not stopping watchdog!\n"); |
| 182 | mpcore_wdt_keepalive(wdt); |
| 183 | } |
| 184 | clear_bit(0, &wdt->timer_alive); |
| 185 | wdt->expect_close = 0; |
| 186 | return 0; |
| 187 | } |
| 188 | |
| 189 | static ssize_t mpcore_wdt_write(struct file *file, const char *data, |
| 190 | size_t len, loff_t *ppos) |
| 191 | { |
| 192 | struct mpcore_wdt *wdt = file->private_data; |
| 193 | |
| 194 | /* |
| 195 | * Refresh the timer. |
| 196 | */ |
| 197 | if (len) { |
| 198 | if (!nowayout) { |
| 199 | size_t i; |
| 200 | |
| 201 | /* In case it was set long ago */ |
| 202 | wdt->expect_close = 0; |
| 203 | |
| 204 | for (i = 0; i != len; i++) { |
| 205 | char c; |
| 206 | |
| 207 | if (get_user(c, data + i)) |
| 208 | return -EFAULT; |
| 209 | if (c == 'V') |
| 210 | wdt->expect_close = 42; |
| 211 | } |
| 212 | } |
| 213 | mpcore_wdt_keepalive(wdt); |
| 214 | } |
| 215 | return len; |
| 216 | } |
| 217 | |
| 218 | static const struct watchdog_info ident = { |
| 219 | .options = WDIOF_SETTIMEOUT | |
| 220 | WDIOF_KEEPALIVEPING | |
| 221 | WDIOF_MAGICCLOSE, |
| 222 | .identity = "MPcore Watchdog", |
| 223 | }; |
| 224 | |
| 225 | static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd, |
| 226 | unsigned long arg) |
| 227 | { |
| 228 | struct mpcore_wdt *wdt = file->private_data; |
| 229 | int ret; |
| 230 | union { |
| 231 | struct watchdog_info ident; |
| 232 | int i; |
| 233 | } uarg; |
| 234 | |
| 235 | if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg)) |
| 236 | return -ENOTTY; |
| 237 | |
| 238 | if (_IOC_DIR(cmd) & _IOC_WRITE) { |
| 239 | ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd)); |
| 240 | if (ret) |
| 241 | return -EFAULT; |
| 242 | } |
| 243 | |
| 244 | switch (cmd) { |
| 245 | case WDIOC_GETSUPPORT: |
| 246 | uarg.ident = ident; |
| 247 | ret = 0; |
| 248 | break; |
| 249 | |
| 250 | case WDIOC_GETSTATUS: |
| 251 | case WDIOC_GETBOOTSTATUS: |
| 252 | uarg.i = 0; |
| 253 | ret = 0; |
| 254 | break; |
| 255 | |
| 256 | case WDIOC_SETOPTIONS: |
| 257 | ret = -EINVAL; |
| 258 | if (uarg.i & WDIOS_DISABLECARD) { |
| 259 | mpcore_wdt_stop(wdt); |
| 260 | ret = 0; |
| 261 | } |
| 262 | if (uarg.i & WDIOS_ENABLECARD) { |
| 263 | mpcore_wdt_start(wdt); |
| 264 | ret = 0; |
| 265 | } |
| 266 | break; |
| 267 | |
| 268 | case WDIOC_KEEPALIVE: |
| 269 | mpcore_wdt_keepalive(wdt); |
| 270 | ret = 0; |
| 271 | break; |
| 272 | |
| 273 | case WDIOC_SETTIMEOUT: |
| 274 | ret = mpcore_wdt_set_heartbeat(uarg.i); |
| 275 | if (ret) |
| 276 | break; |
| 277 | |
| 278 | mpcore_wdt_keepalive(wdt); |
| 279 | /* Fall */ |
| 280 | case WDIOC_GETTIMEOUT: |
| 281 | uarg.i = mpcore_margin; |
| 282 | ret = 0; |
| 283 | break; |
| 284 | |
| 285 | default: |
| 286 | return -ENOTTY; |
| 287 | } |
| 288 | |
| 289 | if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) { |
| 290 | ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd)); |
| 291 | if (ret) |
| 292 | ret = -EFAULT; |
| 293 | } |
| 294 | return ret; |
| 295 | } |
| 296 | |
| 297 | /* |
| 298 | * System shutdown handler. Turn off the watchdog if we're |
| 299 | * restarting or halting the system. |
| 300 | */ |
| 301 | static void mpcore_wdt_shutdown(struct platform_device *dev) |
| 302 | { |
| 303 | struct mpcore_wdt *wdt = platform_get_drvdata(dev); |
| 304 | |
| 305 | if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT) |
| 306 | mpcore_wdt_stop(wdt); |
| 307 | } |
| 308 | |
| 309 | /* |
| 310 | * Kernel Interfaces |
| 311 | */ |
| 312 | static const struct file_operations mpcore_wdt_fops = { |
| 313 | .owner = THIS_MODULE, |
| 314 | .llseek = no_llseek, |
| 315 | .write = mpcore_wdt_write, |
| 316 | .unlocked_ioctl = mpcore_wdt_ioctl, |
| 317 | .open = mpcore_wdt_open, |
| 318 | .release = mpcore_wdt_release, |
| 319 | }; |
| 320 | |
| 321 | static struct miscdevice mpcore_wdt_miscdev = { |
| 322 | .minor = WATCHDOG_MINOR, |
| 323 | .name = "watchdog", |
| 324 | .fops = &mpcore_wdt_fops, |
| 325 | }; |
| 326 | |
| 327 | static int __devinit mpcore_wdt_probe(struct platform_device *dev) |
| 328 | { |
| 329 | struct mpcore_wdt *wdt; |
| 330 | struct resource *res; |
| 331 | int ret; |
| 332 | |
| 333 | /* We only accept one device, and it must have an id of -1 */ |
| 334 | if (dev->id != -1) |
| 335 | return -ENODEV; |
| 336 | |
| 337 | res = platform_get_resource(dev, IORESOURCE_MEM, 0); |
| 338 | if (!res) { |
| 339 | ret = -ENODEV; |
| 340 | goto err_out; |
| 341 | } |
| 342 | |
| 343 | wdt = kzalloc(sizeof(struct mpcore_wdt), GFP_KERNEL); |
| 344 | if (!wdt) { |
| 345 | ret = -ENOMEM; |
| 346 | goto err_out; |
| 347 | } |
| 348 | |
| 349 | wdt->dev = &dev->dev; |
| 350 | wdt->irq = platform_get_irq(dev, 0); |
| 351 | if (wdt->irq < 0) { |
| 352 | ret = -ENXIO; |
| 353 | goto err_free; |
| 354 | } |
| 355 | wdt->base = ioremap(res->start, resource_size(res)); |
| 356 | if (!wdt->base) { |
| 357 | ret = -ENOMEM; |
| 358 | goto err_free; |
| 359 | } |
| 360 | |
| 361 | mpcore_wdt_miscdev.parent = &dev->dev; |
| 362 | ret = misc_register(&mpcore_wdt_miscdev); |
| 363 | if (ret) { |
| 364 | dev_printk(KERN_ERR, wdt->dev, |
| 365 | "cannot register miscdev on minor=%d (err=%d)\n", |
| 366 | WATCHDOG_MINOR, ret); |
| 367 | goto err_misc; |
| 368 | } |
| 369 | |
| 370 | ret = request_irq(wdt->irq, mpcore_wdt_fire, 0, "mpcore_wdt", wdt); |
| 371 | if (ret) { |
| 372 | dev_printk(KERN_ERR, wdt->dev, |
| 373 | "cannot register IRQ%d for watchdog\n", wdt->irq); |
| 374 | goto err_irq; |
| 375 | } |
| 376 | |
| 377 | mpcore_wdt_stop(wdt); |
| 378 | platform_set_drvdata(dev, wdt); |
| 379 | mpcore_wdt_dev = dev; |
| 380 | |
| 381 | return 0; |
| 382 | |
| 383 | err_irq: |
| 384 | misc_deregister(&mpcore_wdt_miscdev); |
| 385 | err_misc: |
| 386 | iounmap(wdt->base); |
| 387 | err_free: |
| 388 | kfree(wdt); |
| 389 | err_out: |
| 390 | return ret; |
| 391 | } |
| 392 | |
| 393 | static int __devexit mpcore_wdt_remove(struct platform_device *dev) |
| 394 | { |
| 395 | struct mpcore_wdt *wdt = platform_get_drvdata(dev); |
| 396 | |
| 397 | platform_set_drvdata(dev, NULL); |
| 398 | |
| 399 | misc_deregister(&mpcore_wdt_miscdev); |
| 400 | |
| 401 | mpcore_wdt_dev = NULL; |
| 402 | |
| 403 | free_irq(wdt->irq, wdt); |
| 404 | iounmap(wdt->base); |
| 405 | kfree(wdt); |
| 406 | return 0; |
| 407 | } |
| 408 | |
| 409 | #ifdef CONFIG_PM |
| 410 | static int mpcore_wdt_suspend(struct platform_device *dev, pm_message_t msg) |
| 411 | { |
| 412 | struct mpcore_wdt *wdt = platform_get_drvdata(dev); |
| 413 | mpcore_wdt_stop(wdt); /* Turn the WDT off */ |
| 414 | return 0; |
| 415 | } |
| 416 | |
| 417 | static int mpcore_wdt_resume(struct platform_device *dev) |
| 418 | { |
| 419 | struct mpcore_wdt *wdt = platform_get_drvdata(dev); |
| 420 | /* re-activate timer */ |
| 421 | if (test_bit(0, &wdt->timer_alive)) |
| 422 | mpcore_wdt_start(wdt); |
| 423 | return 0; |
| 424 | } |
| 425 | #else |
| 426 | #define mpcore_wdt_suspend NULL |
| 427 | #define mpcore_wdt_resume NULL |
| 428 | #endif |
| 429 | |
| 430 | /* work with hotplug and coldplug */ |
| 431 | MODULE_ALIAS("platform:mpcore_wdt"); |
| 432 | |
| 433 | static struct platform_driver mpcore_wdt_driver = { |
| 434 | .probe = mpcore_wdt_probe, |
| 435 | .remove = __devexit_p(mpcore_wdt_remove), |
| 436 | .suspend = mpcore_wdt_suspend, |
| 437 | .resume = mpcore_wdt_resume, |
| 438 | .shutdown = mpcore_wdt_shutdown, |
| 439 | .driver = { |
| 440 | .owner = THIS_MODULE, |
| 441 | .name = "mpcore_wdt", |
| 442 | }, |
| 443 | }; |
| 444 | |
| 445 | static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. " |
| 446 | "mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n"; |
| 447 | |
| 448 | static int __init mpcore_wdt_init(void) |
| 449 | { |
| 450 | /* |
| 451 | * Check that the margin value is within it's range; |
| 452 | * if not reset to the default |
| 453 | */ |
| 454 | if (mpcore_wdt_set_heartbeat(mpcore_margin)) { |
| 455 | mpcore_wdt_set_heartbeat(TIMER_MARGIN); |
| 456 | printk(KERN_INFO "mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n", |
| 457 | TIMER_MARGIN); |
| 458 | } |
| 459 | |
| 460 | printk(banner, mpcore_noboot, mpcore_margin, nowayout); |
| 461 | |
| 462 | return platform_driver_register(&mpcore_wdt_driver); |
| 463 | } |
| 464 | |
| 465 | static void __exit mpcore_wdt_exit(void) |
| 466 | { |
| 467 | platform_driver_unregister(&mpcore_wdt_driver); |
| 468 | } |
| 469 | |
| 470 | module_init(mpcore_wdt_init); |
| 471 | module_exit(mpcore_wdt_exit); |
| 472 | |
| 473 | MODULE_AUTHOR("ARM Limited"); |
| 474 | MODULE_DESCRIPTION("MPcore Watchdog Device Driver"); |
| 475 | MODULE_LICENSE("GPL"); |
| 476 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |