diff options
Diffstat (limited to 'kernel/drivers/watchdog/at91rm9200_wdt.c')
| -rw-r--r-- | kernel/drivers/watchdog/at91rm9200_wdt.c | 346 |
1 files changed, 346 insertions, 0 deletions
diff --git a/kernel/drivers/watchdog/at91rm9200_wdt.c b/kernel/drivers/watchdog/at91rm9200_wdt.c new file mode 100644 index 000000000..41cecb557 --- /dev/null +++ b/kernel/drivers/watchdog/at91rm9200_wdt.c @@ -0,0 +1,346 @@ +/* + * 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/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 (!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"); + + 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"); |