alim7101_wdt.c 10.9 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449
/*
 *	ALi M7101 PMU Computer Watchdog Timer driver
 *
 *	Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net>
 *	and the Cobalt kernel WDT timer driver by Tim Hockin
 *	                                      <thockin@cobaltnet.com>
 *
 *	(c)2002 Steve Hill <steve@navaho.co.uk>
 *
 *  This WDT driver is different from most other Linux WDT
 *  drivers in that the driver will ping the watchdog by itself,
 *  because this particular WDT has a very short timeout (1.6
 *  seconds) and it would be insane to count on any userspace
 *  daemon always getting scheduled within that time frame.
 *
 *  Additions:
 *   Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs
 *                  found on very old cobalt hardware.
 *                  -- Mike Waychison <michael.waychison@sun.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/io.h>
#include <linux/uaccess.h>


#define WDT_ENABLE 0x9C
#define WDT_DISABLE 0x8C

#define ALI_7101_WDT    0x92
#define ALI_7101_GPIO   0x7D
#define ALI_7101_GPIO_O 0x7E
#define ALI_WDT_ARM     0x01

/*
 * We're going to use a 1 second timeout.
 * If we reset the watchdog every ~250ms we should be safe.  */

#define WDT_INTERVAL (HZ/4+1)

/*
 * We must not require too good response from the userspace daemon.
 * Here we require the userspace daemon to send us a heartbeat
 * char to /dev/watchdog every 30 seconds.
 */

#define WATCHDOG_TIMEOUT 30            /* 30 sec default timeout */
/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
static int timeout = WATCHDOG_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
		"Watchdog timeout in seconds. (1<=timeout<=3600, default="
				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");

static int use_gpio; /* Use the pic (for a1d revision alim7101) */
module_param(use_gpio, int, 0);
MODULE_PARM_DESC(use_gpio,
		"Use the gpio watchdog (required by old cobalt boards).");

static void wdt_timer_ping(unsigned long);
static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1);
static unsigned long next_heartbeat;
static unsigned long wdt_is_open;
static char wdt_expect_close;
static struct pci_dev *alim7101_pmu;

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
		"Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

/*
 *	Whack the dog
 */

static void wdt_timer_ping(unsigned long data)
{
	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
	 * we agree to ping the WDT
	 */
	char tmp;

	if (time_before(jiffies, next_heartbeat)) {
		/* Ping the WDT (this is actually a disarm/arm sequence) */
		pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
		pci_write_config_byte(alim7101_pmu,
					ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
		pci_write_config_byte(alim7101_pmu,
					ALI_7101_WDT, (tmp | ALI_WDT_ARM));
		if (use_gpio) {
			pci_read_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, &tmp);
			pci_write_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, tmp | 0x20);
			pci_write_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, tmp & ~0x20);
		}
	} else {
		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
	}
	/* Re-set the timer interval */
	mod_timer(&timer, jiffies + WDT_INTERVAL);
}

/*
 * Utility routines
 */

static void wdt_change(int writeval)
{
	char tmp;

	pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
	if (writeval == WDT_ENABLE) {
		pci_write_config_byte(alim7101_pmu,
					ALI_7101_WDT, (tmp | ALI_WDT_ARM));
		if (use_gpio) {
			pci_read_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, &tmp);
			pci_write_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, tmp & ~0x20);
		}

	} else {
		pci_write_config_byte(alim7101_pmu,
					ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
		if (use_gpio) {
			pci_read_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, &tmp);
			pci_write_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, tmp | 0x20);
		}
	}
}

static void wdt_startup(void)
{
	next_heartbeat = jiffies + (timeout * HZ);

	/* We must enable before we kick off the timer in case the timer
	   occurs as we ping it */

	wdt_change(WDT_ENABLE);

	/* Start the timer */
	mod_timer(&timer, jiffies + WDT_INTERVAL);

	pr_info("Watchdog timer is now enabled\n");
}

static void wdt_turnoff(void)
{
	/* Stop the timer */
	del_timer_sync(&timer);
	wdt_change(WDT_DISABLE);
	pr_info("Watchdog timer is now disabled...\n");
}

static void wdt_keepalive(void)
{
	/* user land ping */
	next_heartbeat = jiffies + (timeout * HZ);
}

/*
 * /dev/watchdog handling
 */

static ssize_t fop_write(struct file *file, const char __user *buf,
						size_t count, loff_t *ppos)
{
	/* See if we got the magic character 'V' and reload the timer */
	if (count) {
		if (!nowayout) {
			size_t ofs;

			/* note: just in case someone wrote the magic character
			 * five months ago... */
			wdt_expect_close = 0;

			/* now scan */
			for (ofs = 0; ofs != count; ofs++) {
				char c;
				if (get_user(c, buf + ofs))
					return -EFAULT;
				if (c == 'V')
					wdt_expect_close = 42;
			}
		}
		/* someone wrote to us, we should restart timer */
		wdt_keepalive();
	}
	return count;
}

static int fop_open(struct inode *inode, struct file *file)
{
	/* Just in case we're already talking to someone... */
	if (test_and_set_bit(0, &wdt_is_open))
		return -EBUSY;
	/* Good, fire up the show */
	wdt_startup();
	return nonseekable_open(inode, file);
}

static int fop_close(struct inode *inode, struct file *file)
{
	if (wdt_expect_close == 42)
		wdt_turnoff();
	else {
		/* wim: shouldn't there be a: del_timer(&timer); */
		pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
	}
	clear_bit(0, &wdt_is_open);
	wdt_expect_close = 0;
	return 0;
}

static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
							| WDIOF_MAGICCLOSE,
		.firmware_version = 1,
		.identity = "ALiM7101",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);
	case WDIOC_SETOPTIONS:
	{
		int new_options, retval = -EINVAL;

		if (get_user(new_options, p))
			return -EFAULT;
		if (new_options & WDIOS_DISABLECARD) {
			wdt_turnoff();
			retval = 0;
		}
		if (new_options & WDIOS_ENABLECARD) {
			wdt_startup();
			retval = 0;
		}
		return retval;
	}
	case WDIOC_KEEPALIVE:
		wdt_keepalive();
		return 0;
	case WDIOC_SETTIMEOUT:
	{
		int new_timeout;

		if (get_user(new_timeout, p))
			return -EFAULT;
		/* arbitrary upper limit */
		if (new_timeout < 1 || new_timeout > 3600)
			return -EINVAL;
		timeout = new_timeout;
		wdt_keepalive();
		/* Fall through */
	}
	case WDIOC_GETTIMEOUT:
		return put_user(timeout, p);
	default:
		return -ENOTTY;
	}
}

static const struct file_operations wdt_fops = {
	.owner		=	THIS_MODULE,
	.llseek		=	no_llseek,
	.write		=	fop_write,
	.open		=	fop_open,
	.release	=	fop_close,
	.unlocked_ioctl	=	fop_ioctl,
};

static struct miscdevice wdt_miscdev = {
	.minor	=	WATCHDOG_MINOR,
	.name	=	"watchdog",
	.fops	=	&wdt_fops,
};

static int wdt_restart_handle(struct notifier_block *this, unsigned long mode,
			      void *cmd)
{
	/*
	 * Cobalt devices have no way of rebooting themselves other
	 * than getting the watchdog to pull reset, so we restart the
	 * watchdog on reboot with no heartbeat.
	 */
	wdt_change(WDT_ENABLE);

	/* loop until the watchdog fires */
	while (true)
		;

	return NOTIFY_DONE;
}

static struct notifier_block wdt_restart_handler = {
	.notifier_call = wdt_restart_handle,
	.priority = 128,
};

/*
 *	Notifier for system down
 */

static int wdt_notify_sys(struct notifier_block *this,
					unsigned long code, void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		wdt_turnoff();

	return NOTIFY_DONE;
}

/*
 *	The WDT needs to learn about soft shutdowns in order to
 *	turn the timebomb registers off.
 */

static struct notifier_block wdt_notifier = {
	.notifier_call = wdt_notify_sys,
};

static void __exit alim7101_wdt_unload(void)
{
	wdt_turnoff();
	/* Deregister */
	misc_deregister(&wdt_miscdev);
	unregister_reboot_notifier(&wdt_notifier);
	unregister_restart_handler(&wdt_restart_handler);
	pci_dev_put(alim7101_pmu);
}

static int __init alim7101_wdt_init(void)
{
	int rc = -EBUSY;
	struct pci_dev *ali1543_south;
	char tmp;

	pr_info("Steve Hill <steve@navaho.co.uk>\n");
	alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
		NULL);
	if (!alim7101_pmu) {
		pr_info("ALi M7101 PMU not present - WDT not set\n");
		return -EBUSY;
	}

	/* Set the WDT in the PMU to 1 second */
	pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);

	ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
		NULL);
	if (!ali1543_south) {
		pr_info("ALi 1543 South-Bridge not present - WDT not set\n");
		goto err_out;
	}
	pci_read_config_byte(ali1543_south, 0x5e, &tmp);
	pci_dev_put(ali1543_south);
	if ((tmp & 0x1e) == 0x00) {
		if (!use_gpio) {
			pr_info("Detected old alim7101 revision 'a1d'.  If this is a cobalt board, set the 'use_gpio' module parameter.\n");
			goto err_out;
		}
		nowayout = 1;
	} else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
		pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
		goto err_out;
	}

	if (timeout < 1 || timeout > 3600) {
		/* arbitrary upper limit */
		timeout = WATCHDOG_TIMEOUT;
		pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
			timeout);
	}

	rc = register_reboot_notifier(&wdt_notifier);
	if (rc) {
		pr_err("cannot register reboot notifier (err=%d)\n", rc);
		goto err_out;
	}

	rc = register_restart_handler(&wdt_restart_handler);
	if (rc) {
		pr_err("cannot register restart handler (err=%d)\n", rc);
		goto err_out_reboot;
	}

	rc = misc_register(&wdt_miscdev);
	if (rc) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       wdt_miscdev.minor, rc);
		goto err_out_restart;
	}

	if (nowayout)
		__module_get(THIS_MODULE);

	pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
		timeout, nowayout);
	return 0;

err_out_restart:
	unregister_restart_handler(&wdt_restart_handler);
err_out_reboot:
	unregister_reboot_notifier(&wdt_notifier);
err_out:
	pci_dev_put(alim7101_pmu);
	return rc;
}

module_init(alim7101_wdt_init);
module_exit(alim7101_wdt_unload);

static const struct pci_device_id alim7101_pci_tbl[] __used = {
	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
	{ }
};

MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);

MODULE_AUTHOR("Steve Hill");
MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
MODULE_LICENSE("GPL");