pcwd.c

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/*
 * PC Watchdog Driver
 * by Ken Hollis ([e-mail])
 *
 * Permission granted from Simon Machell ([e-mail])
 * Written for the Linux Kernel, and GPLed by Ken Hollis
 *
 * 960107	Added request_region routines, modulized the whole thing.
 * 960108	Fixed end-of-file pointer (Thanks to Dan Hollis), added
 *		WD_TIMEOUT define.
 * 960216	Added eof marker on the file, and changed verbose messages.
 * 960716	Made functional and cosmetic changes to the source for
 *		inclusion in Linux 2.0.x kernels, thanks to Alan Cox.
 * 960717	Removed read/seek routines, replaced with ioctl.  Also, added
 *		check_region command due to Alan's suggestion.
 * 960821	Made changes to compile in newer 2.0.x kernels.  Added
 *		"cold reboot sense" entry.
 * 960825	Made a few changes to code, deleted some defines and made
 *		typedefs to replace them.  Made heartbeat reset only available
 *		via ioctl, and removed the write routine.
 * 960828	Added new items for PC Watchdog Rev.C card.
 * 960829	Changed around all of the IOCTLs, added new features,
 *		added watchdog disable/re-enable routines.  Added firmware
 *		version reporting.  Added read routine for temperature.
 *		Removed some extra defines, added an autodetect Revision
 *		routine.
 * 961006       Revised some documentation, fixed some cosmetic bugs.  Made
 *              drivers to panic the system if it's overheating at bootup.
 * 961118	Changed some verbiage on some of the output, tidied up
 *		code bits, and added compatibility to 2.1.x.
 * 970912       Enabled board on open and disable on close.
 * 971107	Took account of recent VFS changes (broke read).
 * 971210       Disable board on initialisation in case board already ticking.
 * 971222       Changed open/close for temperature handling
 *              Michael Meskes <[e-mail]>.
 * 980112       Used minor numbers from include/linux/miscdevice.h
 * 990403       Clear reset status after reading control status register in
 *              pcwd_showprevstate(). [Marc Boucher <[e-mail]>]
 * 990605	Made changes to code to support Firmware 1.22a, added
 *		fairly useless proc entry.
 * 990610	removed said useless proc code for the merge <alan>
 * 000403	Removed last traces of proc code. <davej>
 * 011214	Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT <[e-mail]>
 *              Added timeout module option to override default
 */

/*
 *	A bells and whistles driver is available from http://www.pcwd.de/
 *	More info available at http://www.berkprod.com/ or http://www.pcwatchdog.com/
 */

#include <linux/config.h>	/* For CONFIG_WATCHDOG_NOWAYOUT/... */
#include <linux/module.h>	/* For module specific items */
#include <linux/moduleparam.h>	/* For new moduleparam's */
#include <linux/types.h>	/* For standard types (like size_t) */
#include <linux/errno.h>	/* For the -ENODEV/... values */
#include <linux/kernel.h>	/* For printk/panic/... */
#include <linux/delay.h>	/* For mdelay function */
#include <linux/timer.h>	/* For timer related operations */
#include <linux/jiffies.h>	/* For jiffies stuff */
#include <linux/miscdevice.h>	/* For MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) */
#include <linux/watchdog.h>	/* For the watchdog specific items */
#include <linux/notifier.h>	/* For notifier support */
#include <linux/reboot.h>	/* For reboot_notifier stuff */
#include <linux/init.h>		/* For __init/__exit/... */
#include <linux/fs.h>		/* For file operations */
#include <linux/ioport.h>	/* For io-port access */
#include <linux/spinlock.h>	/* For spin_lock/spin_unlock/... */
#include <linux/sched.h>	/* TASK_INTERRUPTIBLE, set_current_state() and friends */
#include <linux/slab.h>		/* For kmalloc */

#include <asm/uaccess.h>	/* For copy_to_user/put_user/... */
#include <asm/io.h>		/* For inb/outb/... */

/* Module and version information */
#define WATCHDOG_VERSION "1.16"
#define WATCHDOG_DATE "03 Jan 2006"
#define WATCHDOG_DRIVER_NAME "ISA-PC Watchdog"
#define WATCHDOG_NAME "pcwd"
#define PFX WATCHDOG_NAME ": "
#define DRIVER_VERSION WATCHDOG_DRIVER_NAME " driver, v" WATCHDOG_VERSION " (" WATCHDOG_DATE ")\n"
#define WD_VER WATCHDOG_VERSION " (" WATCHDOG_DATE ")"

/*
 * It should be noted that PCWD_REVISION_B was removed because A and B
 * are essentially the same types of card, with the exception that B
 * has temperature reporting.  Since I didn't receive a Rev.B card,
 * the Rev.B card is not supported.  (It's a good thing too, as they
 * are no longer in production.)
 */
#define	PCWD_REVISION_A		1
#define	PCWD_REVISION_C		2

/*
 * These are the defines that describe the control status bits for the
 * PCI-PC Watchdog card.
*/
/* Port 1 : Control Status #1 for the PC Watchdog card, revision A. */
#define WD_WDRST                0x01	/* Previously reset state */
#define WD_T110                 0x02	/* Temperature overheat sense */
#define WD_HRTBT                0x04	/* Heartbeat sense */
#define WD_RLY2                 0x08	/* External relay triggered */
#define WD_SRLY2                0x80	/* Software external relay triggered */
/* Port 1 : Control Status #1 for the PC Watchdog card, revision C. */
#define WD_REVC_WTRP            0x01	/* Watchdog Trip status */
#define WD_REVC_HRBT            0x02	/* Watchdog Heartbeat */
#define WD_REVC_TTRP            0x04	/* Temperature Trip status */
/* Port 2 : Control Status #2 */
#define WD_WDIS			0x10	/* Watchdog Disabled */
#define WD_ENTP			0x20	/* Watchdog Enable Temperature Trip */
#define WD_SSEL			0x40	/* Watchdog Switch Select (1:SW1 <-> 0:SW2) */
#define WD_WCMD			0x80	/* Watchdog Command Mode */

/* max. time we give an ISA watchdog card to process a command */
/* 500ms for each 4 bit response (according to spec.) */
#define ISA_COMMAND_TIMEOUT     1000

/* Watchdog's internal commands */
#define CMD_ISA_IDLE			0x00
#define CMD_ISA_VERSION_INTEGER		0x01
#define CMD_ISA_VERSION_TENTH		0x02
#define CMD_ISA_VERSION_HUNDRETH	0x03
#define CMD_ISA_VERSION_MINOR		0x04
#define CMD_ISA_SWITCH_SETTINGS		0x05
#define CMD_ISA_DELAY_TIME_2SECS	0x0A
#define CMD_ISA_DELAY_TIME_4SECS	0x0B
#define CMD_ISA_DELAY_TIME_8SECS	0x0C

/*
 * We are using an kernel timer to do the pinging of the watchdog
 * every ~500ms. We try to set the internal heartbeat of the
 * watchdog to 2 ms.
 */

#define WDT_INTERVAL (HZ/2+1)

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

/* internal variables */
static atomic_t open_allowed = ATOMIC_INIT(1);
static char expect_close;
static int temp_panic;
static struct {				/* this is private data for each ISA-PC watchdog card */
	int revision;			/* The card's revision */
	int supports_temp;		/* Wether or not the card has a temperature device */
	int command_mode;		/* Wether or not the card is in command mode */
	int boot_status;		/* The card's boot status */
	int io_addr;			/* The cards I/O address */
	spinlock_t io_lock;		/* the lock for io operations */
	struct timer_list timer;	/* The timer that pings the watchdog */
	unsigned long next_heartbeat;	/* the next_heartbeat for the timer */
} pcwd_private;

/* module parameters */
#define WATCHDOG_HEARTBEAT 60		/* 60 sec default heartbeat */
static int heartbeat = WATCHDOG_HEARTBEAT;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<=heartbeat<=7200, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");

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

/*
 *	Internal functions
 */

static int send_isa_command(int cmd)
{
	int i;
	int control_status;
	int port0, last_port0;	/* Double read for stabilising */

	/* The WCMD bit must be 1 and the command is only 4 bits in size */
	control_status = (cmd & 0x0F) | WD_WCMD;
	outb_p(control_status, pcwd_private.io_addr + 2);
	udelay(ISA_COMMAND_TIMEOUT);

	port0 = inb_p(pcwd_private.io_addr);
	for (i = 0; i < 25; ++i) {
		last_port0 = port0;
		port0 = inb_p(pcwd_private.io_addr);

		if (port0 == last_port0)
			break;	/* Data is stable */

		udelay (250);
	}

	return port0;
}

static int set_command_mode(void)
{
	int i, found=0, count=0;

	/* Set the card into command mode */
	spin_lock(&pcwd_private.io_lock);
	while ((!found) && (count < 3)) {
		i = send_isa_command(CMD_ISA_IDLE);

		if (i == 0x00)
			found = 1;
		else if (i == 0xF3) {
			/* Card does not like what we've done to it */
			outb_p(0x00, pcwd_private.io_addr + 2);
			udelay(1200);	/* Spec says wait 1ms */
			outb_p(0x00, pcwd_private.io_addr + 2);
			udelay(ISA_COMMAND_TIMEOUT);
		}
		count++;
	}
	spin_unlock(&pcwd_private.io_lock);
	pcwd_private.command_mode = found;

	return(found);
}

static void unset_command_mode(void)
{
	/* Set the card into normal mode */
	spin_lock(&pcwd_private.io_lock);
	outb_p(0x00, pcwd_private.io_addr + 2);
	udelay(ISA_COMMAND_TIMEOUT);
	spin_unlock(&pcwd_private.io_lock);

	pcwd_private.command_mode = 0;
}

static inline void pcwd_check_temperature_support(void)
{
	if (inb(pcwd_private.io_addr) != 0xF0)
		pcwd_private.supports_temp = 1;
}

static inline char *get_firmware(void)
{
	int one, ten, hund, minor;
	char *ret;

	ret = kmalloc(6, GFP_KERNEL);
	if(ret == NULL)
		return NULL;

	if (set_command_mode()) {
		one = send_isa_command(CMD_ISA_VERSION_INTEGER);
		ten = send_isa_command(CMD_ISA_VERSION_TENTH);
		hund = send_isa_command(CMD_ISA_VERSION_HUNDRETH);
		minor = send_isa_command(CMD_ISA_VERSION_MINOR);
		sprintf(ret, "%c.%c%c%c", one, ten, hund, minor);
	}
	else
		sprintf(ret, "ERROR");

	unset_command_mode();
	return(ret);
}

static inline int pcwd_get_option_switches(void)
{
	int option_switches=0;

	if (set_command_mode()) {
		/* Get switch settings */
		option_switches = send_isa_command(CMD_ISA_SWITCH_SETTINGS);
	}

	unset_command_mode();
	return(option_switches);
}

static void pcwd_show_card_info(void)
{
	char *firmware;
	int option_switches;

	/* Get some extra info from the hardware (in command/debug/diag mode) */
	if (pcwd_private.revision == PCWD_REVISION_A)
		printk(KERN_INFO PFX "ISA-PC Watchdog (REV.A) detected at port 0x%04x\n", pcwd_private.io_addr);
	else if (pcwd_private.revision == PCWD_REVISION_C) {
		firmware = get_firmware();
		printk(KERN_INFO PFX "ISA-PC Watchdog (REV.C) detected at port 0x%04x (Firmware version: %s)\n",
			pcwd_private.io_addr, firmware);
		kfree(firmware);
		option_switches = pcwd_get_option_switches();
		printk(KERN_INFO PFX "Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
			option_switches,
			((option_switches & 0x10) ? "ON" : "OFF"),
			((option_switches & 0x08) ? "ON" : "OFF"));

		/* Reprogram internal heartbeat to 2 seconds */
		if (set_command_mode()) {
			send_isa_command(CMD_ISA_DELAY_TIME_2SECS);
			unset_command_mode();
		}
	}

	if (pcwd_private.supports_temp)
		printk(KERN_INFO PFX "Temperature Option Detected\n");

	if (pcwd_private.boot_status & WDIOF_CARDRESET)
		printk(KERN_INFO PFX "Previous reboot was caused by the card\n");

	if (pcwd_private.boot_status & WDIOF_OVERHEAT) {
		printk(KERN_EMERG PFX "Card senses a CPU Overheat. Panicking!\n");
		printk(KERN_EMERG PFX "CPU Overheat\n");
	}

	if (pcwd_private.boot_status == 0)
		printk(KERN_INFO PFX "No previous trip detected - Cold boot or reset\n");
}

static void pcwd_timer_ping(unsigned long data)
{
	int wdrst_stat;

	/* If we got a heartbeat pulse within the WDT_INTERVAL
	 * we agree to ping the WDT */
	if(time_before(jiffies, pcwd_private.next_heartbeat)) {
		/* Ping the watchdog */
		spin_lock(&pcwd_private.io_lock);
		if (pcwd_private.revision == PCWD_REVISION_A) {
			/*  Rev A cards are reset by setting the WD_WDRST bit in register 1 */
			wdrst_stat = inb_p(pcwd_private.io_addr);
			wdrst_stat &= 0x0F;
			wdrst_stat |= WD_WDRST;

			outb_p(wdrst_stat, pcwd_private.io_addr + 1);
		} else {
			/* Re-trigger watchdog by writing to port 0 */
			outb_p(0x00, pcwd_private.io_addr);
		}

		/* Re-set the timer interval */
		mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);

		spin_unlock(&pcwd_private.io_lock);
	} else {
		printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
	}
}

static int pcwd_start(void)
{
	int stat_reg;

	pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);

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

	/* Enable the port */
	if (pcwd_private.revision == PCWD_REVISION_C) {
		spin_lock(&pcwd_private.io_lock);
		outb_p(0x00, pcwd_private.io_addr + 3);
		udelay(ISA_COMMAND_TIMEOUT);
		stat_reg = inb_p(pcwd_private.io_addr + 2);
		spin_unlock(&pcwd_private.io_lock);
		if (stat_reg & WD_WDIS) {
			printk(KERN_INFO PFX "Could not start watchdog\n");
			return -EIO;
		}
	}
	return 0;
}

static int pcwd_stop(void)
{
	int stat_reg;

	/* Stop the timer */
	del_timer(&pcwd_private.timer);

	/*  Disable the board  */
	if (pcwd_private.revision == PCWD_REVISION_C) {
		spin_lock(&pcwd_private.io_lock);
		outb_p(0xA5, pcwd_private.io_addr + 3);
		udelay(ISA_COMMAND_TIMEOUT);
		outb_p(0xA5, pcwd_private.io_addr + 3);
		udelay(ISA_COMMAND_TIMEOUT);
		stat_reg = inb_p(pcwd_private.io_addr + 2);
		spin_unlock(&pcwd_private.io_lock);
		if ((stat_reg & WD_WDIS) == 0) {
			printk(KERN_INFO PFX "Could not stop watchdog\n");
			return -EIO;
		}
	}
	return 0;
}

static int pcwd_keepalive(void)
{
	/* user land ping */
	pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
	return 0;
}

static int pcwd_set_heartbeat(int t)
{
	if ((t < 2) || (t > 7200)) /* arbitrary upper limit */
		return -EINVAL;

	heartbeat = t;
	return 0;
}

static int pcwd_get_status(int *status)
{
	int card_status;

	*status=0;
	spin_lock(&pcwd_private.io_lock);
	if (pcwd_private.revision == PCWD_REVISION_A)
		/* Rev A cards return status information from
		 * the base register, which is used for the
		 * temperature in other cards. */
		card_status = inb(pcwd_private.io_addr);
	else {
		/* Rev C cards return card status in the base
		 * address + 1 register. And use different bits
		 * to indicate a card initiated reset, and an
		 * over-temperature condition. And the reboot
		 * status can be reset. */
		card_status = inb(pcwd_private.io_addr + 1);
	}
	spin_unlock(&pcwd_private.io_lock);

	if (pcwd_private.revision == PCWD_REVISION_A) {
		if (card_status & WD_WDRST)
			*status |= WDIOF_CARDRESET;

		if (card_status & WD_T110) {
			*status |= WDIOF_OVERHEAT;
			if (temp_panic) {
				printk (KERN_INFO PFX "Temperature overheat trip!\n");
				kernel_power_off();
			}
		}
	} else {
		if (card_status & WD_REVC_WTRP)
			*status |= WDIOF_CARDRESET;

		if (card_status & WD_REVC_TTRP) {
			*status |= WDIOF_OVERHEAT;
			if (temp_panic) {
				printk (KERN_INFO PFX "Temperature overheat trip!\n");
				kernel_power_off();
			}
		}
	}

	return 0;
}

static int pcwd_clear_status(void)
{
	if (pcwd_private.revision == PCWD_REVISION_C) {
		spin_lock(&pcwd_private.io_lock);
		outb_p(0x00, pcwd_private.io_addr + 1); /* clear reset status */
		spin_unlock(&pcwd_private.io_lock);
	}
	return 0;
}

static int pcwd_get_temperature(int *temperature)
{
	/* check that port 0 gives temperature info and no command results */