1 files changed, 490 insertions, 0 deletions
diff --git a/drivers/watchdog/shwdt.c b/drivers/watchdog/shwdt.c
new file mode 100644
index 00000000..93958a77
--- /dev/null
+++ b/drivers/watchdog/shwdt.c
@@ -0,0 +1,490 @@
+/*
+ * drivers/watchdog/shwdt.c
+ *
+ * Watchdog driver for integrated watchdog in the SuperH processors.
+ *
+ * Copyright (C) 2001 - 2010  Paul Mundt <lethal@linux-sh.org>
+ *
+ * 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.
+ *
+ * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
+ *     Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
+ *
+ * 19-Apr-2002 Rob Radez <rob@osinvestor.com>
+ *     Added expect close support, made emulated timeout runtime changeable
+ *     general cleanups, add some ioctls
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/reboot.h>
+#include <linux/notifier.h>
+#include <linux/ioport.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <asm/watchdog.h>
+
+#define DRV_NAME "sh-wdt"
+
+/*
+ * Default clock division ratio is 5.25 msecs. For an additional table of
+ * values, consult the asm-sh/watchdog.h. Overload this at module load
+ * time.
+ *
+ * In order for this to work reliably we need to have HZ set to 1000 or
+ * something quite higher than 100 (or we need a proper high-res timer
+ * implementation that will deal with this properly), otherwise the 10ms
+ * resolution of a jiffy is enough to trigger the overflow. For things like
+ * the SH-4 and SH-5, this isn't necessarily that big of a problem, though
+ * for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely
+ * necssary.
+ *
+ * As a result of this timing problem, the only modes that are particularly
+ * feasible are the 4096 and the 2048 divisors, which yield 5.25 and 2.62ms
+ * overflow periods respectively.
+ *
+ * Also, since we can't really expect userspace to be responsive enough
+ * before the overflow happens, we maintain two separate timers .. One in
+ * the kernel for clearing out WOVF every 2ms or so (again, this depends on
+ * HZ == 1000), and another for monitoring userspace writes to the WDT device.
+ *
+ * As such, we currently use a configurable heartbeat interval which defaults
+ * to 30s. In this case, the userspace daemon is only responsible for periodic
+ * writes to the device before the next heartbeat is scheduled. If the daemon
+ * misses its deadline, the kernel timer will allow the WDT to overflow.
+ */
+static int clock_division_ratio = WTCSR_CKS_4096;
+#define next_ping_period(cks)	(jiffies + msecs_to_jiffies(cks - 4))
+
+static const struct watchdog_info sh_wdt_info;
+static struct platform_device *sh_wdt_dev;
+static DEFINE_SPINLOCK(shwdt_lock);
+
+#define WATCHDOG_HEARTBEAT 30			/* 30 sec default heartbeat */
+static int heartbeat = WATCHDOG_HEARTBEAT;	/* in seconds */
+static bool nowayout = WATCHDOG_NOWAYOUT;
+static unsigned long next_heartbeat;
+
+struct sh_wdt {
+	void __iomem		*base;
+	struct device		*dev;
+
+	struct timer_list	timer;
+
+	unsigned long		enabled;
+	char			expect_close;
+};
+
+static void sh_wdt_start(struct sh_wdt *wdt)
+{
+	unsigned long flags;
+	u8 csr;
+
+	spin_lock_irqsave(&shwdt_lock, flags);
+
+	next_heartbeat = jiffies + (heartbeat * HZ);
+	mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
+
+	csr = sh_wdt_read_csr();
+	csr |= WTCSR_WT | clock_division_ratio;
+	sh_wdt_write_csr(csr);
+
+	sh_wdt_write_cnt(0);
+
+	/*
+	 * These processors have a bit of an inconsistent initialization
+	 * process.. starting with SH-3, RSTS was moved to WTCSR, and the
+	 * RSTCSR register was removed.
+	 *
+	 * On the SH-2 however, in addition with bits being in different
+	 * locations, we must deal with RSTCSR outright..
+	 */
+	csr = sh_wdt_read_csr();
+	csr |= WTCSR_TME;
+	csr &= ~WTCSR_RSTS;
+	sh_wdt_write_csr(csr);
+
+#ifdef CONFIG_CPU_SH2
+	csr = sh_wdt_read_rstcsr();
+	csr &= ~RSTCSR_RSTS;
+	sh_wdt_write_rstcsr(csr);
+#endif
+	spin_unlock_irqrestore(&shwdt_lock, flags);
+}
+
+static void sh_wdt_stop(struct sh_wdt *wdt)
+{
+	unsigned long flags;
+	u8 csr;
+
+	spin_lock_irqsave(&shwdt_lock, flags);
+
+	del_timer(&wdt->timer);
+
+	csr = sh_wdt_read_csr();
+	csr &= ~WTCSR_TME;
+	sh_wdt_write_csr(csr);
+
+	spin_unlock_irqrestore(&shwdt_lock, flags);
+}
+
+static inline void sh_wdt_keepalive(struct sh_wdt *wdt)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&shwdt_lock, flags);
+	next_heartbeat = jiffies + (heartbeat * HZ);
+	spin_unlock_irqrestore(&shwdt_lock, flags);
+}
+
+static int sh_wdt_set_heartbeat(int t)
+{
+	unsigned long flags;
+
+	if (unlikely(t < 1 || t > 3600)) /* arbitrary upper limit */
+		return -EINVAL;
+
+	spin_lock_irqsave(&shwdt_lock, flags);
+	heartbeat = t;
+	spin_unlock_irqrestore(&shwdt_lock, flags);
+	return 0;
+}
+
+static void sh_wdt_ping(unsigned long data)
+{
+	struct sh_wdt *wdt = (struct sh_wdt *)data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&shwdt_lock, flags);
+	if (time_before(jiffies, next_heartbeat)) {
+		u8 csr;
+
+		csr = sh_wdt_read_csr();
+		csr &= ~WTCSR_IOVF;
+		sh_wdt_write_csr(csr);
+
+		sh_wdt_write_cnt(0);
+
+		mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
+	} else
+		dev_warn(wdt->dev, "Heartbeat lost! Will not ping "
+		         "the watchdog\n");
+	spin_unlock_irqrestore(&shwdt_lock, flags);
+}
+
+static int sh_wdt_open(struct inode *inode, struct file *file)
+{
+	struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev);
+
+	if (test_and_set_bit(0, &wdt->enabled))
+		return -EBUSY;
+	if (nowayout)
+		__module_get(THIS_MODULE);
+
+	file->private_data = wdt;
+
+	sh_wdt_start(wdt);
+
+	return nonseekable_open(inode, file);
+}
+
+static int sh_wdt_close(struct inode *inode, struct file *file)
+{
+	struct sh_wdt *wdt = file->private_data;
+
+	if (wdt->expect_close == 42) {
+		sh_wdt_stop(wdt);
+	} else {
+		dev_crit(wdt->dev, "Unexpected close, not "
+		         "stopping watchdog!\n");
+		sh_wdt_keepalive(wdt);
+	}
+
+	clear_bit(0, &wdt->enabled);
+	wdt->expect_close = 0;
+
+	return 0;
+}
+
+static ssize_t sh_wdt_write(struct file *file, const char *buf,
+			    size_t count, loff_t *ppos)
+{
+	struct sh_wdt *wdt = file->private_data;
+
+	if (count) {
+		if (!nowayout) {
+			size_t i;
+
+			wdt->expect_close = 0;
+
+			for (i = 0; i != count; i++) {
+				char c;
+				if (get_user(c, buf + i))
+					return -EFAULT;
+				if (c == 'V')
+					wdt->expect_close = 42;
+			}
+		}
+		sh_wdt_keepalive(wdt);
+	}
+
+	return count;
+}
+
+static long sh_wdt_ioctl(struct file *file, unsigned int cmd,
+							unsigned long arg)
+{
+	struct sh_wdt *wdt = file->private_data;
+	int new_heartbeat;
+	int options, retval = -EINVAL;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		return copy_to_user((struct watchdog_info *)arg,
+			  &sh_wdt_info, sizeof(sh_wdt_info)) ? -EFAULT : 0;
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, (int *)arg);
+	case WDIOC_SETOPTIONS:
+		if (get_user(options, (int *)arg))
+			return -EFAULT;
+
+		if (options & WDIOS_DISABLECARD) {
+			sh_wdt_stop(wdt);
+			retval = 0;
+		}
+
+		if (options & WDIOS_ENABLECARD) {
+			sh_wdt_start(wdt);
+			retval = 0;
+		}
+
+		return retval;
+	case WDIOC_KEEPALIVE:
+		sh_wdt_keepalive(wdt);
+		return 0;
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_heartbeat, (int *)arg))
+			return -EFAULT;
+
+		if (sh_wdt_set_heartbeat(new_heartbeat))
+			return -EINVAL;
+
+		sh_wdt_keepalive(wdt);
+		/* Fall */
+	case WDIOC_GETTIMEOUT:
+		return put_user(heartbeat, (int *)arg);
+	default:
+		return -ENOTTY;
+	}
+	return 0;
+}
+
+static int sh_wdt_notify_sys(struct notifier_block *this,
+			     unsigned long code, void *unused)
+{
+	struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev);
+
+	if (code == SYS_DOWN || code == SYS_HALT)
+		sh_wdt_stop(wdt);
+
+	return NOTIFY_DONE;
+}
+
+static const struct file_operations sh_wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.write		= sh_wdt_write,
+	.unlocked_ioctl	= sh_wdt_ioctl,
+	.open		= sh_wdt_open,
+	.release	= sh_wdt_close,
+};
+
+static const struct watchdog_info sh_wdt_info = {
+	.options		= WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
+				  WDIOF_MAGICCLOSE,
+	.firmware_version	= 1,
+	.identity		= "SH WDT",
+};
+
+static struct notifier_block sh_wdt_notifier = {
+	.notifier_call		= sh_wdt_notify_sys,
+};
+
+static struct miscdevice sh_wdt_miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= "watchdog",
+	.fops		= &sh_wdt_fops,
+};
+
+static int __devinit sh_wdt_probe(struct platform_device *pdev)
+{
+	struct sh_wdt *wdt;
+	struct resource *res;
+	int rc;
+
+	/*
+	 * As this driver only covers the global watchdog case, reject
+	 * any attempts to register per-CPU watchdogs.
+	 */
+	if (pdev->id != -1)
+		return -EINVAL;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (unlikely(!res))
+		return -EINVAL;
+
+	if (!devm_request_mem_region(&pdev->dev, res->start,
+				     resource_size(res), DRV_NAME))
+		return -EBUSY;
+
+	wdt = devm_kzalloc(&pdev->dev, sizeof(struct sh_wdt), GFP_KERNEL);
+	if (unlikely(!wdt)) {
+		rc = -ENOMEM;
+		goto out_release;
+	}
+
+	wdt->dev = &pdev->dev;
+
+	wdt->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+	if (unlikely(!wdt->base)) {
+		rc = -ENXIO;
+		goto out_err;
+	}
+
+	rc = register_reboot_notifier(&sh_wdt_notifier);
+	if (unlikely(rc)) {
+		dev_err(&pdev->dev,
+			"Can't register reboot notifier (err=%d)\n", rc);
+		goto out_unmap;
+	}
+
+	sh_wdt_miscdev.parent = wdt->dev;
+
+	rc = misc_register(&sh_wdt_miscdev);
+	if (unlikely(rc)) {
+		dev_err(&pdev->dev,
+			"Can't register miscdev on minor=%d (err=%d)\n",
+						sh_wdt_miscdev.minor, rc);
+		goto out_unreg;
+	}
+
+	init_timer(&wdt->timer);
+	wdt->timer.function	= sh_wdt_ping;
+	wdt->timer.data		= (unsigned long)wdt;
+	wdt->timer.expires	= next_ping_period(clock_division_ratio);
+
+	platform_set_drvdata(pdev, wdt);
+	sh_wdt_dev = pdev;
+
+	dev_info(&pdev->dev, "initialized.\n");
+
+	return 0;
+
+out_unreg:
+	unregister_reboot_notifier(&sh_wdt_notifier);
+out_unmap:
+	devm_iounmap(&pdev->dev, wdt->base);
+out_err:
+	devm_kfree(&pdev->dev, wdt);
+out_release:
+	devm_release_mem_region(&pdev->dev, res->start, resource_size(res));
+
+	return rc;
+}
+
+static int __devexit sh_wdt_remove(struct platform_device *pdev)
+{
+	struct sh_wdt *wdt = platform_get_drvdata(pdev);
+	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	platform_set_drvdata(pdev, NULL);
+
+	misc_deregister(&sh_wdt_miscdev);
+
+	sh_wdt_dev = NULL;
+
+	unregister_reboot_notifier(&sh_wdt_notifier);
+	devm_release_mem_region(&pdev->dev, res->start, resource_size(res));
+	devm_iounmap(&pdev->dev, wdt->base);
+	devm_kfree(&pdev->dev, wdt);
+
+	return 0;
+}
+
+static struct platform_driver sh_wdt_driver = {
+	.driver		= {
+		.name	= DRV_NAME,
+		.owner	= THIS_MODULE,
+	},
+
+	.probe	= sh_wdt_probe,
+	.remove	= __devexit_p(sh_wdt_remove),
+};
+
+static int __init sh_wdt_init(void)
+{
+	int rc;
+
+	if (unlikely(clock_division_ratio < 0x5 ||
+		     clock_division_ratio > 0x7)) {
+		clock_division_ratio = WTCSR_CKS_4096;
+
+		pr_info("divisor must be 0x5<=x<=0x7, using %d\n",
+			clock_division_ratio);
+	}
+
+	rc = sh_wdt_set_heartbeat(heartbeat);
+	if (unlikely(rc)) {
+		heartbeat = WATCHDOG_HEARTBEAT;
+
+		pr_info("heartbeat value must be 1<=x<=3600, using %d\n",
+			heartbeat);
+	}
+
+	pr_info("configured with heartbeat=%d sec (nowayout=%d)\n",
+		heartbeat, nowayout);
+
+	return platform_driver_register(&sh_wdt_driver);
+}
+
+static void __exit sh_wdt_exit(void)
+{
+	platform_driver_unregister(&sh_wdt_driver);
+}
+module_init(sh_wdt_init);
+module_exit(sh_wdt_exit);
+
+MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
+MODULE_DESCRIPTION("SuperH watchdog driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+
+module_param(clock_division_ratio, int, 0);
+MODULE_PARM_DESC(clock_division_ratio,
+	"Clock division ratio. Valid ranges are from 0x5 (1.31ms) "
+	"to 0x7 (5.25ms). (default=" __MODULE_STRING(WTCSR_CKS_4096) ")");
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+	"Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default="
+				__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+	"Watchdog cannot be stopped once started (default="
+				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");