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- // 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 stream_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");
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