1 files changed, 342 insertions, 0 deletions
diff --git a/drivers/watchdog/at91rm9200_wdt.c b/drivers/watchdog/at91rm9200_wdt.c
new file mode 100644
index 000000000..b45fc0aee
--- /dev/null
+++ b/drivers/watchdog/at91rm9200_wdt.c
@@ -0,0 +1,342 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Watchdog driver for Atmel AT91RM9200 (Thunder)
+ *
+ *  Copyright (C) 2003 SAN People (Pty) Ltd
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/atmel-st.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/uaccess.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#define WDT_DEFAULT_TIME	5	/* seconds */
+#define WDT_MAX_TIME		256	/* seconds */
+
+static int wdt_time = WDT_DEFAULT_TIME;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+static struct regmap *regmap_st;
+
+module_param(wdt_time, int, 0);
+MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
+				__MODULE_STRING(WDT_DEFAULT_TIME) ")");
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+		"Watchdog cannot be stopped once started (default="
+				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+#endif
+
+
+static unsigned long at91wdt_busy;
+
+/* ......................................................................... */
+
+static int at91rm9200_restart(struct notifier_block *this,
+					unsigned long mode, void *cmd)
+{
+	/*
+	 * Perform a hardware reset with the use of the Watchdog timer.
+	 */
+	regmap_write(regmap_st, AT91_ST_WDMR,
+		     AT91_ST_RSTEN | AT91_ST_EXTEN | 1);
+	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
+
+	mdelay(2000);
+
+	pr_emerg("Unable to restart system\n");
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block at91rm9200_restart_nb = {
+	.notifier_call = at91rm9200_restart,
+	.priority = 192,
+};
+
+/*
+ * Disable the watchdog.
+ */
+static inline void at91_wdt_stop(void)
+{
+	regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
+}
+
+/*
+ * Enable and reset the watchdog.
+ */
+static inline void at91_wdt_start(void)
+{
+	regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
+				(((65536 * wdt_time) >> 8) & AT91_ST_WDV));
+	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
+}
+
+/*
+ * Reload the watchdog timer.  (ie, pat the watchdog)
+ */
+static inline void at91_wdt_reload(void)
+{
+	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
+}
+
+/* ......................................................................... */
+
+/*
+ * Watchdog device is opened, and watchdog starts running.
+ */
+static int at91_wdt_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(0, &at91wdt_busy))
+		return -EBUSY;
+
+	at91_wdt_start();
+	return nonseekable_open(inode, file);
+}
+
+/*
+ * Close the watchdog device.
+ * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
+ *  disabled.
+ */
+static int at91_wdt_close(struct inode *inode, struct file *file)
+{
+	/* Disable the watchdog when file is closed */
+	if (!nowayout)
+		at91_wdt_stop();
+
+	clear_bit(0, &at91wdt_busy);
+	return 0;
+}
+
+/*
+ * Change the watchdog time interval.
+ */
+static int at91_wdt_settimeout(int new_time)
+{
+	/*
+	 * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
+	 *
+	 * Since WDV is a 16-bit counter, the maximum period is
+	 * 65536 / 256 = 256 seconds.
+	 */
+	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
+		return -EINVAL;
+
+	/* Set new watchdog time. It will be used when
+	   at91_wdt_start() is called. */
+	wdt_time = new_time;
+	return 0;
+}
+
+static const struct watchdog_info at91_wdt_info = {
+	.identity	= "at91 watchdog",
+	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+};
+
+/*
+ * Handle commands from user-space.
+ */
+static long at91_wdt_ioctl(struct file *file,
+					unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	int new_value;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		return copy_to_user(argp, &at91_wdt_info,
+				sizeof(at91_wdt_info)) ? -EFAULT : 0;
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+	case WDIOC_SETOPTIONS:
+		if (get_user(new_value, p))
+			return -EFAULT;
+		if (new_value & WDIOS_DISABLECARD)
+			at91_wdt_stop();
+		if (new_value & WDIOS_ENABLECARD)
+			at91_wdt_start();
+		return 0;
+	case WDIOC_KEEPALIVE:
+		at91_wdt_reload();	/* pat the watchdog */
+		return 0;
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_value, p))
+			return -EFAULT;
+		if (at91_wdt_settimeout(new_value))
+			return -EINVAL;
+		/* Enable new time value */
+		at91_wdt_start();
+		/* Return current value */
+		return put_user(wdt_time, p);
+	case WDIOC_GETTIMEOUT:
+		return put_user(wdt_time, p);
+	default:
+		return -ENOTTY;
+	}
+}
+
+/*
+ * Pat the watchdog whenever device is written to.
+ */
+static ssize_t at91_wdt_write(struct file *file, const char *data,
+						size_t len, loff_t *ppos)
+{
+	at91_wdt_reload();		/* pat the watchdog */
+	return len;
+}
+
+/* ......................................................................... */
+
+static const struct file_operations at91wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.unlocked_ioctl	= at91_wdt_ioctl,
+	.open		= at91_wdt_open,
+	.release	= at91_wdt_close,
+	.write		= at91_wdt_write,
+};
+
+static struct miscdevice at91wdt_miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= "watchdog",
+	.fops		= &at91wdt_fops,
+};
+
+static int at91wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device *parent;
+	int res;
+
+	if (at91wdt_miscdev.parent)
+		return -EBUSY;
+	at91wdt_miscdev.parent = &pdev->dev;
+
+	parent = dev->parent;
+	if (!parent) {
+		dev_err(dev, "no parent\n");
+		return -ENODEV;
+	}
+
+	regmap_st = syscon_node_to_regmap(parent->of_node);
+	if (IS_ERR(regmap_st))
+		return -ENODEV;
+
+	res = misc_register(&at91wdt_miscdev);
+	if (res)
+		return res;
+
+	res = register_restart_handler(&at91rm9200_restart_nb);
+	if (res)
+		dev_warn(dev, "failed to register restart handler\n");
+
+	pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
+		wdt_time, nowayout ? ", nowayout" : "");
+	return 0;
+}
+
+static int at91wdt_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int res;
+
+	res = unregister_restart_handler(&at91rm9200_restart_nb);
+	if (res)
+		dev_warn(dev, "failed to unregister restart handler\n");
+
+	misc_deregister(&at91wdt_miscdev);
+	at91wdt_miscdev.parent = NULL;
+
+	return res;
+}
+
+static void at91wdt_shutdown(struct platform_device *pdev)
+{
+	at91_wdt_stop();
+}
+
+#ifdef CONFIG_PM
+
+static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
+{
+	at91_wdt_stop();
+	return 0;
+}
+
+static int at91wdt_resume(struct platform_device *pdev)
+{
+	if (at91wdt_busy)
+		at91_wdt_start();
+	return 0;
+}
+
+#else
+#define at91wdt_suspend NULL
+#define at91wdt_resume	NULL
+#endif
+
+static const struct of_device_id at91_wdt_dt_ids[] = {
+	{ .compatible = "atmel,at91rm9200-wdt" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
+
+static struct platform_driver at91wdt_driver = {
+	.probe		= at91wdt_probe,
+	.remove		= at91wdt_remove,
+	.shutdown	= at91wdt_shutdown,
+	.suspend	= at91wdt_suspend,
+	.resume		= at91wdt_resume,
+	.driver		= {
+		.name	= "atmel_st_watchdog",
+		.of_match_table = at91_wdt_dt_ids,
+	},
+};
+
+static int __init at91_wdt_init(void)
+{
+	/* Check that the heartbeat value is within range;
+	   if not reset to the default */
+	if (at91_wdt_settimeout(wdt_time)) {
+		at91_wdt_settimeout(WDT_DEFAULT_TIME);
+		pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
+			wdt_time);
+	}
+
+	return platform_driver_register(&at91wdt_driver);
+}
+
+static void __exit at91_wdt_exit(void)
+{
+	platform_driver_unregister(&at91wdt_driver);
+}
+
+module_init(at91_wdt_init);
+module_exit(at91_wdt_exit);
+
+MODULE_AUTHOR("Andrew Victor");
+MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:atmel_st_watchdog");