| /* |
| * 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/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/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; |
| |
| /* ......................................................................... */ |
| |
| /* |
| * 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 (!regmap_st) |
| return -ENODEV; |
| |
| 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 = "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"); |