/* * Watchdog driver for Atmel AT91RM9200 (Thunder) * * Copyright (C) 2003 SAN People (Pty) Ltd * * 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. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/bitops.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/miscdevice.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/platform_device.h> #include <linux/types.h> #include <linux/watchdog.h> #include <linux/uaccess.h> #include <linux/of.h> #include <linux/of_device.h> #include <mach/at91_st.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; 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; /* ......................................................................... */ /* * Disable the watchdog. */ static inline void at91_wdt_stop(void) { at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN); } /* * Enable and reset the watchdog. */ static inline void at91_wdt_start(void) { at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | (((65536 * wdt_time) >> 8) & AT91_ST_WDV)); at91_st_write(AT91_ST_CR, AT91_ST_WDRST); } /* * Reload the watchdog timer. (ie, pat the watchdog) */ static inline void at91_wdt_reload(void) { at91_st_write(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) { int res; if (at91wdt_miscdev.parent) return -EBUSY; at91wdt_miscdev.parent = &pdev->dev; res = misc_register(&at91wdt_miscdev); if (res) return res; pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n", wdt_time, nowayout ? ", nowayout" : ""); return 0; } static int at91wdt_remove(struct platform_device *pdev) { int res; res = misc_deregister(&at91wdt_miscdev); if (!res) 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 = "at91_wdt", .owner = THIS_MODULE, .of_match_table = of_match_ptr(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_MISCDEV(WATCHDOG_MINOR); MODULE_ALIAS("platform:at91_wdt");