[WATCHDOG] New SBC8360 watchdog driver (revised)

New SBC8360 watchdog driver patch

From: Ian E. Morgan <imorgan@webcon.ca>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@osdl.org>

1 files changed, 419 insertions, 0 deletions

diff --git a/drivers/char/watchdog/sbc8360.c b/drivers/char/watchdog/sbc8360.c
new file mode 100644
index 000000000000..06daf426d5b6
--- /dev/null
+++ b/drivers/char/watchdog/sbc8360.c
@@ -0,0 +1,419 @@
+/*
+ *	SBC8360 Watchdog driver
+ *
+ *	(c) Copyright 2005 Webcon, Inc.
+ *
+ *	Based on ib700wdt.c, which is based on advantechwdt.c which is based
+ *      on acquirewdt.c which is based on wdt.c.
+ *
+ *	(c) Copyright 2001 Charles Howes <chowes@vsol.net>
+ *
+ *      Based on advantechwdt.c which is based on acquirewdt.c which
+ *       is based on wdt.c.
+ *
+ *	(c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
+ *
+ *	Based on acquirewdt.c which is based on wdt.c.
+ *	Original copyright messages:
+ *
+ *	(c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
+ *				http://www.redhat.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.
+ *
+ *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
+ *	warranty for any of this software. This material is provided
+ *	"AS-IS" and at no charge.
+ *
+ *	(c) Copyright 1995    Alan Cox <alan@redhat.com>
+ *
+ *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
+ *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
+ *           Added timeout module option to override default
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/ioport.h>
+#include <linux/delay.h>
+#include <linux/notifier.h>
+#include <linux/fs.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/moduleparam.h>
+
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+static unsigned long sbc8360_is_open;
+static spinlock_t sbc8360_lock;
+static char expect_close;
+
+#define PFX "sbc8360: "
+
+/*
+ *
+ * Watchdog Timer Configuration
+ *
+ * The function of the watchdog timer is to reset the system automatically
+ * and is defined at I/O port 0120H and 0121H.  To enable the watchdog timer
+ * and allow the system to reset, write appropriate values from the table
+ * below to I/O port 0120H and 0121H.  To disable the timer, write a zero
+ * value to I/O port 0121H for the system to stop the watchdog function.
+ *
+ * The following describes how the timer should be programmed (according to
+ * the vendor documentation)
+ *
+ * Enabling Watchdog:
+ * MOV AX,000AH (enable, phase I)
+ * MOV DX,0120H
+ * OUT DX,AX
+ * MOV AX,000BH (enable, phase II)
+ * MOV DX,0120H
+ * OUT DX,AX
+ * MOV AX,000nH (set multiplier n, from 1-4)
+ * MOV DX,0120H
+ * OUT DX,AX
+ * MOV AX,000mH (set base timer m, from 0-F)
+ * MOV DX,0121H
+ * OUT DX,AX
+ *
+ * Reset timer:
+ * MOV AX,000mH (same as set base timer, above)
+ * MOV DX,0121H
+ * OUT DX,AX
+ *
+ * Disabling Watchdog:
+ * MOV AX,0000H (a zero value)
+ * MOV DX,0120H
+ * OUT DX,AX
+ *
+ * Watchdog timeout configuration values:
+ *		N
+ *	M |	1	2	3	4
+ *	--|----------------------------------
+ *	0 |	0.5s	5s	50s	100s
+ *	1 |	1s	10s	100s	200s
+ *	2 |	1.5s	15s	150s	300s
+ *	3 |	2s	20s	200s	400s
+ *	4 |	2.5s	25s	250s	500s
+ *	5 |	3s	30s	300s	600s
+ *	6 |	3.5s	35s	350s	700s
+ *	7 |	4s	40s	400s	800s
+ *	8 |	4.5s	45s	450s	900s
+ *	9 |	5s	50s	500s	1000s
+ *	A |	5.5s	55s	550s	1100s
+ *	B |	6s	60s	600s	1200s
+ *	C |	6.5s	65s	650s	1300s
+ *	D |	7s	70s	700s	1400s
+ *	E |	7.5s	75s	750s	1500s
+ *	F |	8s	80s 	800s 	1600s
+ *
+ * Another way to say the same things is:
+ *  For N=1, Timeout = (M+1) * 0.5s
+ *  For N=2, Timeout = (M+1) * 5s
+ *  For N=3, Timeout = (M+1) * 50s
+ *  For N=4, Timeout = (M+1) * 100s
+ *
+ */
+
+static int wd_times[64][2] = {
+	{0, 1},			/* 0  = 0.5s */
+	{1, 1},			/* 1  = 1s   */
+	{2, 1},			/* 2  = 1.5s */
+	{3, 1},			/* 3  = 2s   */
+	{4, 1},			/* 4  = 2.5s */
+	{5, 1},			/* 5  = 3s   */
+	{6, 1},			/* 6  = 3.5s */
+	{7, 1},			/* 7  = 4s   */
+	{8, 1},			/* 8  = 4.5s */
+	{9, 1},			/* 9  = 5s   */
+	{0xA, 1},		/* 10 = 5.5s */
+	{0xB, 1},		/* 11 = 6s   */
+	{0xC, 1},		/* 12 = 6.5s */
+	{0xD, 1},		/* 13 = 7s   */
+	{0xE, 1},		/* 14 = 7.5s */
+	{0xF, 1},		/* 15 = 8s   */
+	{0, 2},			/* 16 = 5s  */
+	{1, 2},			/* 17 = 10s */
+	{2, 2},			/* 18 = 15s */
+	{3, 2},			/* 19 = 20s */
+	{4, 2},			/* 20 = 25s */
+	{5, 2},			/* 21 = 30s */
+	{6, 2},			/* 22 = 35s */
+	{7, 2},			/* 23 = 40s */
+	{8, 2},			/* 24 = 45s */
+	{9, 2},			/* 25 = 50s */
+	{0xA, 2},		/* 26 = 55s */
+	{0xB, 2},		/* 27 = 60s */
+	{0xC, 2},		/* 28 = 65s */
+	{0xD, 2},		/* 29 = 70s */
+	{0xE, 2},		/* 30 = 75s */
+	{0xF, 2},		/* 31 = 80s */
+	{0, 3},			/* 32 = 50s  */
+	{1, 3},			/* 33 = 100s */
+	{2, 3},			/* 34 = 150s */
+	{3, 3},			/* 35 = 200s */
+	{4, 3},			/* 36 = 250s */
+	{5, 3},			/* 37 = 300s */
+	{6, 3},			/* 38 = 350s */
+	{7, 3},			/* 39 = 400s */
+	{8, 3},			/* 40 = 450s */
+	{9, 3},			/* 41 = 500s */
+	{0xA, 3},		/* 42 = 550s */
+	{0xB, 3},		/* 43 = 600s */
+	{0xC, 3},		/* 44 = 650s */
+	{0xD, 3},		/* 45 = 700s */
+	{0xE, 3},		/* 46 = 750s */
+	{0xF, 3},		/* 47 = 800s */
+	{0, 4},			/* 48 = 100s */
+	{1, 4},			/* 49 = 200s */
+	{2, 4},			/* 50 = 300s */
+	{3, 4},			/* 51 = 400s */
+	{4, 4},			/* 52 = 500s */
+	{5, 4},			/* 53 = 600s */
+	{6, 4},			/* 54 = 700s */
+	{7, 4},			/* 55 = 800s */
+	{8, 4},			/* 56 = 900s */
+	{9, 4},			/* 57 = 1000s */
+	{0xA, 4},		/* 58 = 1100s */
+	{0xB, 4},		/* 59 = 1200s */
+	{0xC, 4},		/* 60 = 1300s */
+	{0xD, 4},		/* 61 = 1400s */
+	{0xE, 4},		/* 62 = 1500s */
+	{0xF, 4}		/* 63 = 1600s */
+};
+
+#define SBC8360_ENABLE 0x120
+#define SBC8360_BASETIME 0x121
+
+static int timeout = 27;
+static int wd_margin = 0xB;
+static int wd_multiplier = 2;
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+static int nowayout = 1;
+#else
+static int nowayout = 0;
+#endif
+
+module_param(timeout, int, 27);
+MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))");
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout,
+		 "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
+
+/*
+ *	Kernel methods.
+ */
+
+/* Activate and pre-configure watchdog */
+static void sbc8360_activate(void)
+{
+	/* Enable the watchdog */
+	outb(0x0A, SBC8360_ENABLE);
+	msleep_interruptible(100);
+	outb(0x0B, SBC8360_ENABLE);
+	msleep_interruptible(100);
+	/* Set timeout multiplier */
+	outb(wd_multiplier, SBC8360_ENABLE);
+	msleep_interruptible(100);
+	/* Nothing happens until first sbc8360_ping() */
+}
+
+/* Kernel pings watchdog */
+static void sbc8360_ping(void)
+{
+	/* Write the base timer register */
+	outb(wd_margin, SBC8360_BASETIME);
+}
+
+/* Userspace pings kernel driver, or requests clean close */
+static ssize_t sbc8360_write(struct file *file, const char __user * buf,
+			     size_t count, loff_t * ppos)
+{
+	if (count) {
+		if (!nowayout) {
+			size_t i;
+
+			/* In case it was set long ago */
+			expect_close = 0;
+
+			for (i = 0; i != count; i++) {
+				char c;
+				if (get_user(c, buf + i))
+					return -EFAULT;
+				if (c == 'V')
+					expect_close = 42;
+			}
+		}
+		sbc8360_ping();
+	}
+	return count;
+}
+
+static int sbc8360_open(struct inode *inode, struct file *file)
+{
+	spin_lock(&sbc8360_lock);
+	if (test_and_set_bit(0, &sbc8360_is_open)) {
+		spin_unlock(&sbc8360_lock);
+		return -EBUSY;
+	}
+	if (nowayout)
+		__module_get(THIS_MODULE);
+
+	/* Activate and ping once to start the countdown */
+	spin_unlock(&sbc8360_lock);
+	sbc8360_activate();
+	sbc8360_ping();
+	return nonseekable_open(inode, file);
+}
+
+static int sbc8360_close(struct inode *inode, struct file *file)
+{
+	spin_lock(&sbc8360_lock);
+	if (expect_close == 42)
+		outb(0, SBC8360_ENABLE);
+	else
+		printk(KERN_CRIT PFX
+		       "SBC8360 device closed unexpectedly.  SBC8360 will not stop!\n");
+
+	clear_bit(0, &sbc8360_is_open);
+	expect_close = 0;
+	spin_unlock(&sbc8360_lock);
+	return 0;
+}
+
+/*
+ *	Notifier for system down
+ */
+
+static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code,
+			      void *unused)
+{
+	if (code == SYS_DOWN || code == SYS_HALT) {
+		/* Disable the SBC8360 Watchdog */
+		outb(0, SBC8360_ENABLE);
+	}
+	return NOTIFY_DONE;
+}
+
+/*
+ *	Kernel Interfaces
+ */
+
+static struct file_operations sbc8360_fops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.write = sbc8360_write,
+	.open = sbc8360_open,
+	.release = sbc8360_close,
+};
+
+static struct miscdevice sbc8360_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name = "watchdog",
+	.fops = &sbc8360_fops,
+};
+
+/*
+ *	The SBC8360 needs to learn about soft shutdowns in order to
+ *	turn the timebomb registers off.
+ */
+
+static struct notifier_block sbc8360_notifier = {
+	.notifier_call = sbc8360_notify_sys,
+};
+
+static int __init sbc8360_init(void)
+{
+	int res;
+	unsigned long int mseconds = 60000;
+
+	spin_lock_init(&sbc8360_lock);
+	res = misc_register(&sbc8360_miscdev);
+	if (res) {
+		printk(KERN_ERR PFX "failed to register misc device\n");
+		goto out_nomisc;
+	}
+
+	if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) {
+		printk(KERN_ERR PFX "ENABLE method I/O %X is not available.\n",
+		       SBC8360_ENABLE);
+		res = -EIO;
+		goto out_noenablereg;
+	}
+	if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) {
+		printk(KERN_ERR PFX
+		       "BASETIME method I/O %X is not available.\n",
+		       SBC8360_BASETIME);
+		res = -EIO;
+		goto out_nobasetimereg;
+	}
+
+	res = register_reboot_notifier(&sbc8360_notifier);
+	if (res) {
+		printk(KERN_ERR PFX "Failed to register reboot notifier.\n");
+		goto out_noreboot;
+	}
+
+	if (timeout < 0 || timeout > 63) {
+		printk(KERN_ERR PFX "Invalid timeout index (must be 0-63).\n");
+		res = -EINVAL;
+		goto out_noreboot;
+	}
+
+	wd_margin = wd_times[timeout][0];
+	wd_multiplier = wd_times[timeout][1];
+
+	if (wd_multiplier == 1)
+		mseconds = (wd_margin + 1) * 500;
+	else if (wd_multiplier == 2)
+		mseconds = (wd_margin + 1) * 5000;
+	else if (wd_multiplier == 3)
+		mseconds = (wd_margin + 1) * 50000;
+	else if (wd_multiplier == 4)
+		mseconds = (wd_margin + 1) * 100000;
+
+	/* My kingdom for the ability to print "0.5 seconds" in the kernel! */
+	printk(KERN_INFO PFX "Timeout set at %ld ms.\n", mseconds);
+
+	return 0;
+
+      out_noreboot:
+	release_region(SBC8360_ENABLE, 1);
+	release_region(SBC8360_BASETIME, 1);
+      out_noenablereg:
+      out_nobasetimereg:
+	misc_deregister(&sbc8360_miscdev);
+      out_nomisc:
+	return res;
+}
+
+static void __exit sbc8360_exit(void)
+{
+	misc_deregister(&sbc8360_miscdev);
+	unregister_reboot_notifier(&sbc8360_notifier);
+	release_region(SBC8360_ENABLE, 1);
+	release_region(SBC8360_BASETIME, 1);
+}
+
+module_init(sbc8360_init);
+module_exit(sbc8360_exit);
+
+MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>");
+MODULE_DESCRIPTION("SBC8360 watchdog driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+
+/* end of sbc8360.c */