Initial import

1 files changed, 434 insertions, 0 deletions

diff --git a/drivers/watchdog/sc520_wdt.c b/drivers/watchdog/sc520_wdt.c
new file mode 100644
index 000000000..1cfd3f6a1
--- /dev/null
+++ b/drivers/watchdog/sc520_wdt.c
@@ -0,0 +1,434 @@
+/*
+ *	AMD Elan SC520 processor Watchdog Timer driver
+ *
+ *	Based on acquirewdt.c by Alan Cox,
+ *	     and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
+ *
+ *	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.
+ *
+ *	The authors do NOT admit liability nor provide warranty for
+ *	any of this software. This material is provided "AS-IS" in
+ *	the hope that it may be useful for others.
+ *
+ *	(c) Copyright 2001    Scott Jennings <linuxdrivers@oro.net>
+ *           9/27 - 2001      [Initial release]
+ *
+ *	Additional fixes Alan Cox
+ *	-	Fixed formatting
+ *	-	Removed debug printks
+ *	-	Fixed SMP built kernel deadlock
+ *	-	Switched to private locks not lock_kernel
+ *	-	Used ioremap/writew/readw
+ *	-	Added NOWAYOUT support
+ *	4/12 - 2002 Changes by Rob Radez <rob@osinvestor.com>
+ *	-	Change comments
+ *	-	Eliminate fop_llseek
+ *	-	Change CONFIG_WATCHDOG_NOWAYOUT semantics
+ *	-	Add KERN_* tags to printks
+ *	-	fix possible wdt_is_open race
+ *	-	Report proper capabilities in watchdog_info
+ *	-	Add WDIOC_{GETSTATUS, GETBOOTSTATUS, SETTIMEOUT,
+ *		GETTIMEOUT, SETOPTIONS} ioctls
+ *	09/8 - 2003 Changes by Wim Van Sebroeck <wim@iguana.be>
+ *	-	cleanup of trailing spaces
+ *	-	added extra printk's for startup problems
+ *	-	use module_param
+ *	-	made timeout (the emulated heartbeat) a module_param
+ *	-	made the keepalive ping an internal subroutine
+ *	3/27 - 2004 Changes by Sean Young <sean@mess.org>
+ *	-	set MMCR_BASE to 0xfffef000
+ *	-	CBAR does not need to be read
+ *	-	removed debugging printks
+ *
+ *  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.
+ *
+ *  This driver uses memory mapped IO, and spinlock.
+ */
+
+#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/fs.h>
+#include <linux/ioport.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+
+
+/*
+ * The AMD Elan SC520 timeout value is 492us times a power of 2 (0-7)
+ *
+ *   0: 492us    2: 1.01s    4: 4.03s   6: 16.22s
+ *   1: 503ms    3: 2.01s    5: 8.05s   7: 32.21s
+ *
+ * We will program the SC520 watchdog for a timeout of 2.01s.
+ * 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 bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+		"Watchdog cannot be stopped once started (default="
+				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+/*
+ * AMD Elan SC520 - Watchdog Timer Registers
+ */
+#define MMCR_BASE	0xfffef000	/* The default base address */
+#define OFFS_WDTMRCTL	0xCB0	/* Watchdog Timer Control Register */
+
+/* WDT Control Register bit definitions */
+#define WDT_EXP_SEL_01	0x0001	/* [01] Time-out = 496 us (with 33 Mhz clk). */
+#define WDT_EXP_SEL_02	0x0002	/* [02] Time-out = 508 ms (with 33 Mhz clk). */
+#define WDT_EXP_SEL_03	0x0004	/* [03] Time-out = 1.02 s (with 33 Mhz clk). */
+#define WDT_EXP_SEL_04	0x0008	/* [04] Time-out = 2.03 s (with 33 Mhz clk). */
+#define WDT_EXP_SEL_05	0x0010	/* [05] Time-out = 4.07 s (with 33 Mhz clk). */
+#define WDT_EXP_SEL_06	0x0020	/* [06] Time-out = 8.13 s (with 33 Mhz clk). */
+#define WDT_EXP_SEL_07	0x0040	/* [07] Time-out = 16.27s (with 33 Mhz clk). */
+#define WDT_EXP_SEL_08	0x0080	/* [08] Time-out = 32.54s (with 33 Mhz clk). */
+#define WDT_IRQ_FLG	0x1000	/* [12] Interrupt Request Flag */
+#define WDT_WRST_ENB	0x4000	/* [14] Watchdog Timer Reset Enable */
+#define WDT_ENB		0x8000	/* [15] Watchdog Timer Enable */
+
+static __u16 __iomem *wdtmrctl;
+
+static void wdt_timer_ping(unsigned long);
+static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
+static unsigned long next_heartbeat;
+static unsigned long wdt_is_open;
+static char wdt_expect_close;
+static DEFINE_SPINLOCK(wdt_spinlock);
+
+/*
+ *	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
+	 */
+	if (time_before(jiffies, next_heartbeat)) {
+		/* Ping the WDT */
+		spin_lock(&wdt_spinlock);
+		writew(0xAAAA, wdtmrctl);
+		writew(0x5555, wdtmrctl);
+		spin_unlock(&wdt_spinlock);
+
+		/* Re-set the timer interval */
+		mod_timer(&timer, jiffies + WDT_INTERVAL);
+	} else
+		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
+}
+
+/*
+ *	Utility routines
+ */
+
+static void wdt_config(int writeval)
+{
+	unsigned long flags;
+
+	/* buy some time (ping) */
+	spin_lock_irqsave(&wdt_spinlock, flags);
+	readw(wdtmrctl);	/* ensure write synchronization */
+	writew(0xAAAA, wdtmrctl);
+	writew(0x5555, wdtmrctl);
+	/* unlock WDT = make WDT configuration register writable one time */
+	writew(0x3333, wdtmrctl);
+	writew(0xCCCC, wdtmrctl);
+	/* write WDT configuration register */
+	writew(writeval, wdtmrctl);
+	spin_unlock_irqrestore(&wdt_spinlock, flags);
+}
+
+static int wdt_startup(void)
+{
+	next_heartbeat = jiffies + (timeout * HZ);
+
+	/* Start the timer */
+	mod_timer(&timer, jiffies + WDT_INTERVAL);
+
+	/* Start the watchdog */
+	wdt_config(WDT_ENB | WDT_WRST_ENB | WDT_EXP_SEL_04);
+
+	pr_info("Watchdog timer is now enabled\n");
+	return 0;
+}
+
+static int wdt_turnoff(void)
+{
+	/* Stop the timer */
+	del_timer(&timer);
+
+	/* Stop the watchdog */
+	wdt_config(0);
+
+	pr_info("Watchdog timer is now disabled...\n");
+	return 0;
+}
+
+static int wdt_keepalive(void)
+{
+	/* user land ping */
+	next_heartbeat = jiffies + (timeout * HZ);
+	return 0;
+}
+
+static int wdt_set_heartbeat(int t)
+{
+	if ((t < 1) || (t > 3600))	/* arbitrary upper limit */
+		return -EINVAL;
+
+	timeout = t;
+	return 0;
+}
+
+/*
+ *	/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;
+			}
+		}
+
+		/* Well, anyhow someone wrote to us, we should
+		   return that favour */
+		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;
+	if (nowayout)
+		__module_get(THIS_MODULE);
+
+	/* 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 {
+		pr_crit("Unexpected close, not stopping watchdog!\n");
+		wdt_keepalive();
+	}
+	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 = "SC520",
+	};
+
+	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;
+
+		if (wdt_set_heartbeat(new_timeout))
+			return -EINVAL;
+
+		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,
+};
+
+/*
+ *	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 sc520_wdt_unload(void)
+{
+	if (!nowayout)
+		wdt_turnoff();
+
+	/* Deregister */
+	misc_deregister(&wdt_miscdev);
+	unregister_reboot_notifier(&wdt_notifier);
+	iounmap(wdtmrctl);
+}
+
+static int __init sc520_wdt_init(void)
+{
+	int rc = -EBUSY;
+
+	/* Check that the timeout value is within it's range ;
+	   if not reset to the default */
+	if (wdt_set_heartbeat(timeout)) {
+		wdt_set_heartbeat(WATCHDOG_TIMEOUT);
+		pr_info("timeout value must be 1 <= timeout <= 3600, using %d\n",
+			WATCHDOG_TIMEOUT);
+	}
+
+	wdtmrctl = ioremap(MMCR_BASE + OFFS_WDTMRCTL, 2);
+	if (!wdtmrctl) {
+		pr_err("Unable to remap memory\n");
+		rc = -ENOMEM;
+		goto err_out_region2;
+	}
+
+	rc = register_reboot_notifier(&wdt_notifier);
+	if (rc) {
+		pr_err("cannot register reboot notifier (err=%d)\n", rc);
+		goto err_out_ioremap;
+	}
+
+	rc = misc_register(&wdt_miscdev);
+	if (rc) {
+		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
+		       WATCHDOG_MINOR, rc);
+		goto err_out_notifier;
+	}
+
+	pr_info("WDT driver for SC520 initialised. timeout=%d sec (nowayout=%d)\n",
+		timeout, nowayout);
+
+	return 0;
+
+err_out_notifier:
+	unregister_reboot_notifier(&wdt_notifier);
+err_out_ioremap:
+	iounmap(wdtmrctl);
+err_out_region2:
+	return rc;
+}
+
+module_init(sc520_wdt_init);
+module_exit(sc520_wdt_unload);
+
+MODULE_AUTHOR("Scott and Bill Jennings");
+MODULE_DESCRIPTION(
+	"Driver for watchdog timer in AMD \"Elan\" SC520 uProcessor");
+MODULE_LICENSE("GPL");