[deliverable/linux.git] / drivers / watchdog / i6300esb.c

/*
 *	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");
Commit	Line	Data
	1	/*
	2	* i6300esb: Watchdog timer driver for Intel 6300ESB chipset
	3	*
	4	* (c) Copyright 2004 Google Inc.
	5	* (c) Copyright 2005 David Härdeman <david@2gen.com>
	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License
	9	* as published by the Free Software Foundation; either version
	10	* 2 of the License, or (at your option) any later version.
	11	*
	12	* based on i810-tco.c which is in turn based on softdog.c
	13	*
	14	* The timer is implemented in the following I/O controller hubs:
	15	* (See the intel documentation on http://developer.intel.com.)
	16	* 6300ESB chip : document number 300641-004
	17	*
	18	* 2004YYZZ Ross Biro
	19	* Initial version 0.01
	20	* 2004YYZZ Ross Biro
	21	* Version 0.02
	22	* 20050210 David Härdeman <david@2gen.com>
	23	* Ported driver to kernel 2.6
	24	*/
	25
	26	/*
	27	* Includes, defines, variables, module parameters, ...
	28	*/
	29
	30	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	31
	32	#include <linux/module.h>
	33	#include <linux/types.h>
	34	#include <linux/kernel.h>
	35	#include <linux/fs.h>
	36	#include <linux/mm.h>
	37	#include <linux/miscdevice.h>
	38	#include <linux/watchdog.h>
	39	#include <linux/pci.h>
	40	#include <linux/ioport.h>
	41	#include <linux/uaccess.h>
	42	#include <linux/io.h>
	43
	44	/* Module and version information */
	45	#define ESB_VERSION "0.05"
	46	#define ESB_MODULE_NAME "i6300ESB timer"
	47	#define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
	48
	49	/* PCI configuration registers */
	50	#define ESB_CONFIG_REG 0x60 /* Config register */
	51	#define ESB_LOCK_REG 0x68 /* WDT lock register */
	52
	53	/* Memory mapped registers */
	54	#define ESB_TIMER1_REG (BASEADDR + 0x00)/* Timer1 value after each reset */
	55	#define ESB_TIMER2_REG (BASEADDR + 0x04)/* Timer2 value after each reset */
	56	#define ESB_GINTSR_REG (BASEADDR + 0x08)/* General Interrupt Status Register */
	57	#define ESB_RELOAD_REG (BASEADDR + 0x0c)/* Reload register */
	58
	59	/* Lock register bits */
	60	#define ESB_WDT_FUNC (0x01 << 2) /* Watchdog functionality */
	61	#define ESB_WDT_ENABLE (0x01 << 1) /* Enable WDT */
	62	#define ESB_WDT_LOCK (0x01 << 0) /* Lock (nowayout) */
	63
	64	/* Config register bits */
	65	#define ESB_WDT_REBOOT (0x01 << 5) /* Enable reboot on timeout */
	66	#define ESB_WDT_FREQ (0x01 << 2) /* Decrement frequency */
	67	#define ESB_WDT_INTTYPE (0x03 << 0) /* Interrupt type on timer1 timeout */
	68
	69	/* Reload register bits */
	70	#define ESB_WDT_TIMEOUT (0x01 << 9) /* Watchdog timed out */
	71	#define ESB_WDT_RELOAD (0x01 << 8) /* prevent timeout */
	72
	73	/* Magic constants */
	74	#define ESB_UNLOCK1 0x80 /* Step 1 to unlock reset registers */
	75	#define ESB_UNLOCK2 0x86 /* Step 2 to unlock reset registers */
	76
	77	/* internal variables */
	78	static void __iomem *BASEADDR;
	79	static DEFINE_SPINLOCK(esb_lock); /* Guards the hardware */
	80	static unsigned long timer_alive;
	81	static struct pci_dev *esb_pci;
	82	static unsigned short triggered; /* The status of the watchdog upon boot */
	83	static char esb_expect_close;
	84
	85	/* We can only use 1 card due to the /dev/watchdog restriction */
	86	static int cards_found;
	87
	88	/* module parameters */
	89	/* 30 sec default heartbeat (1 < heartbeat < 21023) /
	90	#define WATCHDOG_HEARTBEAT 30
	91	static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
	92	module_param(heartbeat, int, 0);
	93	MODULE_PARM_DESC(heartbeat,
	94	"Watchdog heartbeat in seconds. (1<heartbeat<2046, default="
	95	__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
	96
	97	static bool nowayout = WATCHDOG_NOWAYOUT;
	98	module_param(nowayout, bool, 0);
	99	MODULE_PARM_DESC(nowayout,
	100	"Watchdog cannot be stopped once started (default="
	101	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	102
	103	/*
	104	* Some i6300ESB specific functions
	105	*/
	106
	107	/*
	108	* Prepare for reloading the timer by unlocking the proper registers.
	109	* This is performed by first writing 0x80 followed by 0x86 to the
	110	* reload register. After this the appropriate registers can be written
	111	* to once before they need to be unlocked again.
	112	*/
	113	static inline void esb_unlock_registers(void)
	114	{
	115	writew(ESB_UNLOCK1, ESB_RELOAD_REG);
	116	writew(ESB_UNLOCK2, ESB_RELOAD_REG);
	117	}
	118
	119	static int esb_timer_start(void)
	120	{
	121	u8 val;
	122
	123	spin_lock(&esb_lock);
	124	esb_unlock_registers();
	125	writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
	126	/* Enable or Enable + Lock? */
	127	val = ESB_WDT_ENABLE \| (nowayout ? ESB_WDT_LOCK : 0x00);
	128	pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
	129	spin_unlock(&esb_lock);
	130	return 0;
	131	}
	132
	133	static int esb_timer_stop(void)
	134	{
	135	u8 val;
	136
	137	spin_lock(&esb_lock);
	138	/* First, reset timers as suggested by the docs */
	139	esb_unlock_registers();
	140	writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
	141	/* Then disable the WDT */
	142	pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
	143	pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
	144	spin_unlock(&esb_lock);
	145
	146	/* Returns 0 if the timer was disabled, non-zero otherwise */
	147	return val & ESB_WDT_ENABLE;
	148	}
	149
	150	static void esb_timer_keepalive(void)
	151	{
	152	spin_lock(&esb_lock);
	153	esb_unlock_registers();
	154	writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
	155	/* FIXME: Do we need to flush anything here? */
	156	spin_unlock(&esb_lock);
	157	}
	158
	159	static int esb_timer_set_heartbeat(int time)
	160	{
	161	u32 val;
	162
	163	if (time < 0x1 \|\| time > (2 * 0x03ff))
	164	return -EINVAL;
	165
	166	spin_lock(&esb_lock);
	167
	168	/* We shift by 9, so if we are passed a value of 1 sec,
	169	* val will be 1 << 9 = 512, then write that to two
	170	* timers => 2 * 512 = 1024 (which is decremented at 1KHz)
	171	*/
	172	val = time << 9;
	173
	174	/* Write timer 1 */
	175	esb_unlock_registers();
	176	writel(val, ESB_TIMER1_REG);
	177
	178	/* Write timer 2 */
	179	esb_unlock_registers();
	180	writel(val, ESB_TIMER2_REG);
	181
	182	/* Reload */
	183	esb_unlock_registers();
	184	writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
	185
	186	/* FIXME: Do we need to flush everything out? */
	187
	188	/* Done */
	189	heartbeat = time;
	190	spin_unlock(&esb_lock);
	191	return 0;
	192	}
	193
	194	/*
	195	* /dev/watchdog handling
	196	*/
	197
	198	static int esb_open(struct inode inode, struct file file)
	199	{
	200	/* /dev/watchdog can only be opened once */
	201	if (test_and_set_bit(0, &timer_alive))
	202	return -EBUSY;
	203
	204	/* Reload and activate timer */
	205	esb_timer_start();
	206
	207	return nonseekable_open(inode, file);
	208	}
	209
	210	static int esb_release(struct inode inode, struct file file)
	211	{
	212	/* Shut off the timer. */
	213	if (esb_expect_close == 42)
	214	esb_timer_stop();
	215	else {
	216	pr_crit("Unexpected close, not stopping watchdog!\n");
	217	esb_timer_keepalive();
	218	}
	219	clear_bit(0, &timer_alive);
	220	esb_expect_close = 0;
	221	return 0;
	222	}
	223
	224	static ssize_t esb_write(struct file file, const char __user data,
	225	size_t len, loff_t *ppos)
	226	{
	227	/* See if we got the magic character 'V' and reload the timer */
	228	if (len) {
	229	if (!nowayout) {
	230	size_t i;
	231
	232	/* note: just in case someone wrote the magic character
	233	* five months ago... */
	234	esb_expect_close = 0;
	235
	236	/* scan to see whether or not we got the
	237	* magic character */
	238	for (i = 0; i != len; i++) {
	239	char c;
	240	if (get_user(c, data + i))
	241	return -EFAULT;
	242	if (c == 'V')
	243	esb_expect_close = 42;
	244	}
	245	}
	246
	247	/* someone wrote to us, we should reload the timer */
	248	esb_timer_keepalive();
	249	}
	250	return len;
	251	}
	252
	253	static long esb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	254	{
	255	int new_options, retval = -EINVAL;
	256	int new_heartbeat;
	257	void __user argp = (void __user )arg;
	258	int __user *p = argp;
	259	static const struct watchdog_info ident = {
	260	.options = WDIOF_SETTIMEOUT \|
	261	WDIOF_KEEPALIVEPING \|
	262	WDIOF_MAGICCLOSE,
	263	.firmware_version = 0,
	264	.identity = ESB_MODULE_NAME,
	265	};
	266
	267	switch (cmd) {
	268	case WDIOC_GETSUPPORT:
	269	return copy_to_user(argp, &ident,
	270	sizeof(ident)) ? -EFAULT : 0;
	271
	272	case WDIOC_GETSTATUS:
	273	return put_user(0, p);
	274
	275	case WDIOC_GETBOOTSTATUS:
	276	return put_user(triggered, p);
	277
	278	case WDIOC_SETOPTIONS:
	279	{
	280	if (get_user(new_options, p))
	281	return -EFAULT;
	282
	283	if (new_options & WDIOS_DISABLECARD) {
	284	esb_timer_stop();
	285	retval = 0;
	286	}
	287
	288	if (new_options & WDIOS_ENABLECARD) {
	289	esb_timer_start();
	290	retval = 0;
	291	}
	292	return retval;
	293	}
	294	case WDIOC_KEEPALIVE:
	295	esb_timer_keepalive();
	296	return 0;
	297
	298	case WDIOC_SETTIMEOUT:
	299	{
	300	if (get_user(new_heartbeat, p))
	301	return -EFAULT;
	302	if (esb_timer_set_heartbeat(new_heartbeat))
	303	return -EINVAL;
	304	esb_timer_keepalive();
	305	/* Fall */
	306	}
	307	case WDIOC_GETTIMEOUT:
	308	return put_user(heartbeat, p);
	309	default:
	310	return -ENOTTY;
	311	}
	312	}
	313
	314	/*
	315	* Kernel Interfaces
	316	*/
	317
	318	static const struct file_operations esb_fops = {
	319	.owner = THIS_MODULE,
	320	.llseek = no_llseek,
	321	.write = esb_write,
	322	.unlocked_ioctl = esb_ioctl,
	323	.open = esb_open,
	324	.release = esb_release,
	325	};
	326
	327	static struct miscdevice esb_miscdev = {
	328	.minor = WATCHDOG_MINOR,
	329	.name = "watchdog",
	330	.fops = &esb_fops,
	331	};
	332
	333	/*
	334	* Data for PCI driver interface
	335	*/
	336	static const struct pci_device_id esb_pci_tbl[] = {
	337	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
	338	{ 0, }, /* End of list */
	339	};
	340	MODULE_DEVICE_TABLE(pci, esb_pci_tbl);
	341
	342	/*
	343	* Init & exit routines
	344	*/
	345
	346	static unsigned char esb_getdevice(struct pci_dev *pdev)
	347	{
	348	if (pci_enable_device(pdev)) {
	349	pr_err("failed to enable device\n");
	350	goto err_devput;
	351	}
	352
	353	if (pci_request_region(pdev, 0, ESB_MODULE_NAME)) {
	354	pr_err("failed to request region\n");
	355	goto err_disable;
	356	}
	357
	358	BASEADDR = pci_ioremap_bar(pdev, 0);
	359	if (BASEADDR == NULL) {
	360	/* Something's wrong here, BASEADDR has to be set */
	361	pr_err("failed to get BASEADDR\n");
	362	goto err_release;
	363	}
	364
	365	/* Done */
	366	esb_pci = pdev;
	367	return 1;
	368
	369	err_release:
	370	pci_release_region(pdev, 0);
	371	err_disable:
	372	pci_disable_device(pdev);
	373	err_devput:
	374	return 0;
	375	}
	376
	377	static void esb_initdevice(void)
	378	{
	379	u8 val1;
	380	u16 val2;
	381
	382	/*
	383	* Config register:
	384	* Bit 5 : 0 = Enable WDT_OUTPUT
	385	* Bit 2 : 0 = set the timer frequency to the PCI clock
	386	* divided by 2^15 (approx 1KHz).
	387	* Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
	388	* The watchdog has two timers, it can be setup so that the
	389	* expiry of timer1 results in an interrupt and the expiry of
	390	* timer2 results in a reboot. We set it to not generate
	391	* any interrupts as there is not much we can do with it
	392	* right now.
	393	*/
	394	pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
	395
	396	/* Check that the WDT isn't already locked */
	397	pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
	398	if (val1 & ESB_WDT_LOCK)
	399	pr_warn("nowayout already set\n");
	400
	401	/* Set the timer to watchdog mode and disable it for now */
	402	pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
	403
	404	/* Check if the watchdog was previously triggered */
	405	esb_unlock_registers();
	406	val2 = readw(ESB_RELOAD_REG);
	407	if (val2 & ESB_WDT_TIMEOUT)
	408	triggered = WDIOF_CARDRESET;
	409
	410	/* Reset WDT_TIMEOUT flag and timers */
	411	esb_unlock_registers();
	412	writew((ESB_WDT_TIMEOUT \| ESB_WDT_RELOAD), ESB_RELOAD_REG);
	413
	414	/* And set the correct timeout value */
	415	esb_timer_set_heartbeat(heartbeat);
	416	}
	417
	418	static int esb_probe(struct pci_dev *pdev,
	419	const struct pci_device_id *ent)
	420	{
	421	int ret;
	422
	423	cards_found++;
	424	if (cards_found == 1)
	425	pr_info("Intel 6300ESB WatchDog Timer Driver v%s\n",
	426	ESB_VERSION);
	427
	428	if (cards_found > 1) {
	429	pr_err("This driver only supports 1 device\n");
	430	return -ENODEV;
	431	}
	432
	433	/* Check whether or not the hardware watchdog is there */
	434	if (!esb_getdevice(pdev) \|\| esb_pci == NULL)
	435	return -ENODEV;
	436
	437	/* Check that the heartbeat value is within it's range;
	438	if not reset to the default */
	439	if (heartbeat < 0x1 \|\| heartbeat > 2 * 0x03ff) {
	440	heartbeat = WATCHDOG_HEARTBEAT;
	441	pr_info("heartbeat value must be 1<heartbeat<2046, using %d\n",
	442	heartbeat);
	443	}
	444
	445	/* Initialize the watchdog and make sure it does not run */
	446	esb_initdevice();
	447
	448	/* Register the watchdog so that userspace has access to it */
	449	ret = misc_register(&esb_miscdev);
	450	if (ret != 0) {
	451	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
	452	WATCHDOG_MINOR, ret);
	453	goto err_unmap;
	454	}
	455	pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
	456	BASEADDR, heartbeat, nowayout);
	457	return 0;
	458
	459	err_unmap:
	460	iounmap(BASEADDR);
	461	pci_release_region(esb_pci, 0);
	462	pci_disable_device(esb_pci);
	463	esb_pci = NULL;
	464	return ret;
	465	}
	466
	467	static void esb_remove(struct pci_dev *pdev)
	468	{
	469	/* Stop the timer before we leave */
	470	if (!nowayout)
	471	esb_timer_stop();
	472
	473	/* Deregister */
	474	misc_deregister(&esb_miscdev);
	475	iounmap(BASEADDR);
	476	pci_release_region(esb_pci, 0);
	477	pci_disable_device(esb_pci);
	478	esb_pci = NULL;
	479	}
	480
	481	static void esb_shutdown(struct pci_dev *pdev)
	482	{
	483	esb_timer_stop();
	484	}
	485
	486	static struct pci_driver esb_driver = {
	487	.name = ESB_MODULE_NAME,
	488	.id_table = esb_pci_tbl,
	489	.probe = esb_probe,
	490	.remove = esb_remove,
	491	.shutdown = esb_shutdown,
	492	};
	493
	494	module_pci_driver(esb_driver);
	495
	496	MODULE_AUTHOR("Ross Biro and David Härdeman");
	497	MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
	498	MODULE_LICENSE("GPL");