i6300esb.c 12.4 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498
/*
 *	i6300esb:	Watchdog timer driver for Intel 6300ESB chipset
 *
 *	(c) Copyright 2004 Google Inc.
 *	(c) Copyright 2005 David Härdeman <david@2gen.com>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 *	based on i810-tco.c which is in turn based on softdog.c
 *
 *	The timer is implemented in the following I/O controller hubs:
 *	(See the intel documentation on http://developer.intel.com.)
 *	6300ESB chip : document number 300641-004
 *
 *  2004YYZZ Ross Biro
 *	Initial version 0.01
 *  2004YYZZ Ross Biro
 *	Version 0.02
 *  20050210 David Härdeman <david@2gen.com>
 *	Ported driver to kernel 2.6
 */

/*
 *      Includes, defines, variables, module parameters, ...
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/uaccess.h>
#include <linux/io.h>

/* Module and version information */
#define ESB_VERSION "0.05"
#define ESB_MODULE_NAME "i6300ESB timer"
#define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION

/* PCI configuration registers */
#define ESB_CONFIG_REG  0x60            /* Config register                   */
#define ESB_LOCK_REG    0x68            /* WDT lock register                 */

/* Memory mapped registers */
#define ESB_TIMER1_REG (BASEADDR + 0x00)/* Timer1 value after each reset     */
#define ESB_TIMER2_REG (BASEADDR + 0x04)/* Timer2 value after each reset     */
#define ESB_GINTSR_REG (BASEADDR + 0x08)/* General Interrupt Status Register */
#define ESB_RELOAD_REG (BASEADDR + 0x0c)/* Reload register                   */

/* Lock register bits */
#define ESB_WDT_FUNC    (0x01 << 2)   /* Watchdog functionality            */
#define ESB_WDT_ENABLE  (0x01 << 1)   /* Enable WDT                        */
#define ESB_WDT_LOCK    (0x01 << 0)   /* Lock (nowayout)                   */

/* Config register bits */
#define ESB_WDT_REBOOT  (0x01 << 5)   /* Enable reboot on timeout          */
#define ESB_WDT_FREQ    (0x01 << 2)   /* Decrement frequency               */
#define ESB_WDT_INTTYPE (0x03 << 0)   /* Interrupt type on timer1 timeout  */

/* Reload register bits */
#define ESB_WDT_TIMEOUT (0x01 << 9)    /* Watchdog timed out                */
#define ESB_WDT_RELOAD  (0x01 << 8)    /* prevent timeout                   */

/* Magic constants */
#define ESB_UNLOCK1     0x80            /* Step 1 to unlock reset registers  */
#define ESB_UNLOCK2     0x86            /* Step 2 to unlock reset registers  */

/* internal variables */
static void __iomem *BASEADDR;
static DEFINE_SPINLOCK(esb_lock); /* Guards the hardware */
static unsigned long timer_alive;
static struct pci_dev *esb_pci;
static unsigned short triggered; /* The status of the watchdog upon boot */
static char esb_expect_close;

/* We can only use 1 card due to the /dev/watchdog restriction */
static int cards_found;

/* module parameters */
/* 30 sec default heartbeat (1 < heartbeat < 2*1023) */
#define WATCHDOG_HEARTBEAT 30
static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
		"Watchdog heartbeat in seconds. (1<heartbeat<2046, default="
				__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");

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) ")");

/*
 * Some i6300ESB specific functions
 */

/*
 * Prepare for reloading the timer by unlocking the proper registers.
 * This is performed by first writing 0x80 followed by 0x86 to the
 * reload register. After this the appropriate registers can be written
 * to once before they need to be unlocked again.
 */
static inline void esb_unlock_registers(void)
{
	writew(ESB_UNLOCK1, ESB_RELOAD_REG);
	writew(ESB_UNLOCK2, ESB_RELOAD_REG);
}

static int esb_timer_start(void)
{
	u8 val;

	spin_lock(&esb_lock);
	esb_unlock_registers();
	writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
	/* Enable or Enable + Lock? */
	val = ESB_WDT_ENABLE | (nowayout ? ESB_WDT_LOCK : 0x00);
	pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
	spin_unlock(&esb_lock);
	return 0;
}

static int esb_timer_stop(void)
{
	u8 val;

	spin_lock(&esb_lock);
	/* First, reset timers as suggested by the docs */
	esb_unlock_registers();
	writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
	/* Then disable the WDT */
	pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
	pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
	spin_unlock(&esb_lock);

	/* Returns 0 if the timer was disabled, non-zero otherwise */
	return val & ESB_WDT_ENABLE;
}

static void esb_timer_keepalive(void)
{
	spin_lock(&esb_lock);
	esb_unlock_registers();
	writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
	/* FIXME: Do we need to flush anything here? */
	spin_unlock(&esb_lock);
}

static int esb_timer_set_heartbeat(int time)
{
	u32 val;

	if (time < 0x1 || time > (2 * 0x03ff))
		return -EINVAL;

	spin_lock(&esb_lock);

	/* We shift by 9, so if we are passed a value of 1 sec,
	 * val will be 1 << 9 = 512, then write that to two
	 * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
	 */
	val = time << 9;

	/* Write timer 1 */
	esb_unlock_registers();
	writel(val, ESB_TIMER1_REG);

	/* Write timer 2 */
	esb_unlock_registers();
	writel(val, ESB_TIMER2_REG);

	/* Reload */
	esb_unlock_registers();
	writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);

	/* FIXME: Do we need to flush everything out? */

	/* Done */
	heartbeat = time;
	spin_unlock(&esb_lock);
	return 0;
}

/*
 *	/dev/watchdog handling
 */

static int esb_open(struct inode *inode, struct file *file)
{
	/* /dev/watchdog can only be opened once */
	if (test_and_set_bit(0, &timer_alive))
		return -EBUSY;

	/* Reload and activate timer */
	esb_timer_start();

	return nonseekable_open(inode, file);
}

static int esb_release(struct inode *inode, struct file *file)
{
	/* Shut off the timer. */
	if (esb_expect_close == 42)
		esb_timer_stop();
	else {
		pr_crit("Unexpected close, not stopping watchdog!\n");
		esb_timer_keepalive();
	}
	clear_bit(0, &timer_alive);
	esb_expect_close = 0;
	return 0;
}

static ssize_t esb_write(struct file *file, const char __user *data,
			  size_t len, loff_t *ppos)
{
	/* See if we got the magic character 'V' and reload the timer */
	if (len) {
		if (!nowayout) {
			size_t i;

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

			/* scan to see whether or not we got the
			 * magic character */
			for (i = 0; i != len; i++) {
				char c;
				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					esb_expect_close = 42;
			}
		}

		/* someone wrote to us, we should reload the timer */
		esb_timer_keepalive();
	}
	return len;
}

static long esb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	int new_options, retval = -EINVAL;
	int new_heartbeat;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
		.options =		WDIOF_SETTIMEOUT |
					WDIOF_KEEPALIVEPING |
					WDIOF_MAGICCLOSE,
		.firmware_version =	0,
		.identity =		ESB_MODULE_NAME,
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ident,
					sizeof(ident)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
		return put_user(0, p);

	case WDIOC_GETBOOTSTATUS:
		return put_user(triggered, p);

	case WDIOC_SETOPTIONS:
	{
		if (get_user(new_options, p))
			return -EFAULT;

		if (new_options & WDIOS_DISABLECARD) {
			esb_timer_stop();
			retval = 0;
		}

		if (new_options & WDIOS_ENABLECARD) {
			esb_timer_start();
			retval = 0;
		}
		return retval;
	}
	case WDIOC_KEEPALIVE:
		esb_timer_keepalive();
		return 0;

	case WDIOC_SETTIMEOUT:
	{
		if (get_user(new_heartbeat, p))
			return -EFAULT;
		if (esb_timer_set_heartbeat(new_heartbeat))
			return -EINVAL;
		esb_timer_keepalive();
		/* Fall */
	}
	case WDIOC_GETTIMEOUT:
		return put_user(heartbeat, p);
	default:
		return -ENOTTY;
	}
}

/*
 *      Kernel Interfaces
 */

static const struct file_operations esb_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = esb_write,
	.unlocked_ioctl = esb_ioctl,
	.open = esb_open,
	.release = esb_release,
};

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

/*
 * Data for PCI driver interface
 */
static const struct pci_device_id esb_pci_tbl[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
	{ 0, },                 /* End of list */
};
MODULE_DEVICE_TABLE(pci, esb_pci_tbl);

/*
 *      Init & exit routines
 */

static unsigned char esb_getdevice(struct pci_dev *pdev)
{
	if (pci_enable_device(pdev)) {
		pr_err("failed to enable device\n");
		goto err_devput;
	}

	if (pci_request_region(pdev, 0, ESB_MODULE_NAME)) {
		pr_err("failed to request region\n");
		goto err_disable;
	}

	BASEADDR = pci_ioremap_bar(pdev, 0);
	if (BASEADDR == NULL) {
		/* Something's wrong here, BASEADDR has to be set */
		pr_err("failed to get BASEADDR\n");
		goto err_release;
	}

	/* Done */
	esb_pci = pdev;
	return 1;

err_release:
	pci_release_region(pdev, 0);
err_disable:
	pci_disable_device(pdev);
err_devput:
	return 0;
}

static void esb_initdevice(void)
{
	u8 val1;
	u16 val2;

	/*
	 * Config register:
	 * Bit    5 : 0 = Enable WDT_OUTPUT
	 * Bit    2 : 0 = set the timer frequency to the PCI clock
	 * divided by 2^15 (approx 1KHz).
	 * Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
	 * The watchdog has two timers, it can be setup so that the
	 * expiry of timer1 results in an interrupt and the expiry of
	 * timer2 results in a reboot. We set it to not generate
	 * any interrupts as there is not much we can do with it
	 * right now.
	 */
	pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);

	/* Check that the WDT isn't already locked */
	pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
	if (val1 & ESB_WDT_LOCK)
		pr_warn("nowayout already set\n");

	/* Set the timer to watchdog mode and disable it for now */
	pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);

	/* Check if the watchdog was previously triggered */
	esb_unlock_registers();
	val2 = readw(ESB_RELOAD_REG);
	if (val2 & ESB_WDT_TIMEOUT)
		triggered = WDIOF_CARDRESET;

	/* Reset WDT_TIMEOUT flag and timers */
	esb_unlock_registers();
	writew((ESB_WDT_TIMEOUT | ESB_WDT_RELOAD), ESB_RELOAD_REG);

	/* And set the correct timeout value */
	esb_timer_set_heartbeat(heartbeat);
}

static int esb_probe(struct pci_dev *pdev,
		const struct pci_device_id *ent)
{
	int ret;

	cards_found++;
	if (cards_found == 1)
		pr_info("Intel 6300ESB WatchDog Timer Driver v%s\n",
			ESB_VERSION);

	if (cards_found > 1) {
		pr_err("This driver only supports 1 device\n");
		return -ENODEV;
	}

	/* Check whether or not the hardware watchdog is there */
	if (!esb_getdevice(pdev) || esb_pci == NULL)
		return -ENODEV;

	/* Check that the heartbeat value is within it's range;
	   if not reset to the default */
	if (heartbeat < 0x1 || heartbeat > 2 * 0x03ff) {
		heartbeat = WATCHDOG_HEARTBEAT;
		pr_info("heartbeat value must be 1<heartbeat<2046, using %d\n",
			heartbeat);
	}

	/* Initialize the watchdog and make sure it does not run */
	esb_initdevice();

	/* Register the watchdog so that userspace has access to it */
	ret = misc_register(&esb_miscdev);
	if (ret != 0) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       WATCHDOG_MINOR, ret);
		goto err_unmap;
	}
	pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
		BASEADDR, heartbeat, nowayout);
	return 0;

err_unmap:
	iounmap(BASEADDR);
	pci_release_region(esb_pci, 0);
	pci_disable_device(esb_pci);
	esb_pci = NULL;
	return ret;
}

static void esb_remove(struct pci_dev *pdev)
{
	/* Stop the timer before we leave */
	if (!nowayout)
		esb_timer_stop();

	/* Deregister */
	misc_deregister(&esb_miscdev);
	iounmap(BASEADDR);
	pci_release_region(esb_pci, 0);
	pci_disable_device(esb_pci);
	esb_pci = NULL;
}

static void esb_shutdown(struct pci_dev *pdev)
{
	esb_timer_stop();
}

static struct pci_driver esb_driver = {
	.name		= ESB_MODULE_NAME,
	.id_table	= esb_pci_tbl,
	.probe          = esb_probe,
	.remove         = esb_remove,
	.shutdown       = esb_shutdown,
};

module_pci_driver(esb_driver);

MODULE_AUTHOR("Ross Biro and David Härdeman");
MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
MODULE_LICENSE("GPL");