/* * FIXME: add wdrtas_get_status and wdrtas_get_boot_status as soon as * RTAS calls are available */ /* * RTAS watchdog driver * * (C) Copyright IBM Corp. 2005 * device driver to exploit watchdog RTAS functions * * Authors : Utz Bacher <utz.bacher@de.ibm.com> * * 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, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/fs.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/miscdevice.h> #include <linux/module.h> #include <linux/notifier.h> #include <linux/reboot.h> #include <linux/types.h> #include <linux/watchdog.h> #include <linux/uaccess.h> #include <asm/rtas.h> #define WDRTAS_MAGIC_CHAR 42 #define WDRTAS_SUPPORTED_MASK (WDIOF_SETTIMEOUT | \ WDIOF_MAGICCLOSE) MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>"); MODULE_DESCRIPTION("RTAS watchdog driver"); MODULE_LICENSE("GPL"); static bool wdrtas_nowayout = WATCHDOG_NOWAYOUT; static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0); static char wdrtas_expect_close; static int wdrtas_interval; #define WDRTAS_THERMAL_SENSOR 3 static int wdrtas_token_get_sensor_state; #define WDRTAS_SURVEILLANCE_IND 9000 static int wdrtas_token_set_indicator; #define WDRTAS_SP_SPI 28 static int wdrtas_token_get_sp; static int wdrtas_token_event_scan; #define WDRTAS_DEFAULT_INTERVAL 300 #define WDRTAS_LOGBUFFER_LEN 128 static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN]; /*** watchdog access functions */ /** * wdrtas_set_interval - sets the watchdog interval * @interval: new interval * * returns 0 on success, <0 on failures * * wdrtas_set_interval sets the watchdog keepalive interval by calling the * RTAS function set-indicator (surveillance). The unit of interval is * seconds. */ static int wdrtas_set_interval(int interval) { long result; static int print_msg = 10; /* rtas uses minutes */ interval = (interval + 59) / 60; result = rtas_call(wdrtas_token_set_indicator, 3, 1, NULL, WDRTAS_SURVEILLANCE_IND, 0, interval); if (result < 0 && print_msg) { pr_err("setting the watchdog to %i timeout failed: %li\n", interval, result); print_msg--; } return result; } #define WDRTAS_SP_SPI_LEN 4 /** * wdrtas_get_interval - returns the current watchdog interval * @fallback_value: value (in seconds) to use, if the RTAS call fails * * returns the interval * * wdrtas_get_interval returns the current watchdog keepalive interval * as reported by the RTAS function ibm,get-system-parameter. The unit * of the return value is seconds. */ static int wdrtas_get_interval(int fallback_value) { long result; char value[WDRTAS_SP_SPI_LEN]; spin_lock(&rtas_data_buf_lock); memset(rtas_data_buf, 0, WDRTAS_SP_SPI_LEN); result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL, WDRTAS_SP_SPI, __pa(rtas_data_buf), WDRTAS_SP_SPI_LEN); memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN); spin_unlock(&rtas_data_buf_lock); if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) { pr_warn("could not get sp_spi watchdog timeout (%li). Continuing\n", result); return fallback_value; } /* rtas uses minutes */ return ((int)value[2]) * 60; } /** * wdrtas_timer_start - starts watchdog * * wdrtas_timer_start starts the watchdog by calling the RTAS function * set-interval (surveillance) */ static void wdrtas_timer_start(void) { wdrtas_set_interval(wdrtas_interval); } /** * wdrtas_timer_stop - stops watchdog * * wdrtas_timer_stop stops the watchdog timer by calling the RTAS function * set-interval (surveillance) */ static void wdrtas_timer_stop(void) { wdrtas_set_interval(0); } /** * wdrtas_timer_keepalive - resets watchdog timer to keep system alive * * wdrtas_timer_keepalive restarts the watchdog timer by calling the * RTAS function event-scan and repeats these calls as long as there are * events available. All events will be dumped. */ static void wdrtas_timer_keepalive(void) { long result; do { result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL, RTAS_EVENT_SCAN_ALL_EVENTS, 0, (void *)__pa(wdrtas_logbuffer), WDRTAS_LOGBUFFER_LEN); if (result < 0) pr_err("event-scan failed: %li\n", result); if (result == 0) print_hex_dump(KERN_INFO, "dumping event, data: ", DUMP_PREFIX_OFFSET, 16, 1, wdrtas_logbuffer, WDRTAS_LOGBUFFER_LEN, false); } while (result == 0); } /** * wdrtas_get_temperature - returns current temperature * * returns temperature or <0 on failures * * wdrtas_get_temperature returns the current temperature in Fahrenheit. It * uses the RTAS call get-sensor-state, token 3 to do so */ static int wdrtas_get_temperature(void) { int result; int temperature = 0; result = rtas_get_sensor(WDRTAS_THERMAL_SENSOR, 0, &temperature); if (result < 0) pr_warn("reading the thermal sensor failed: %i\n", result); else temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */ return temperature; } /** * wdrtas_get_status - returns the status of the watchdog * * returns a bitmask of defines WDIOF_... as defined in * include/linux/watchdog.h */ static int wdrtas_get_status(void) { return 0; /* TODO */ } /** * wdrtas_get_boot_status - returns the reason for the last boot * * returns a bitmask of defines WDIOF_... as defined in * include/linux/watchdog.h, indicating why the watchdog rebooted the system */ static int wdrtas_get_boot_status(void) { return 0; /* TODO */ } /*** watchdog API and operations stuff */ /* wdrtas_write - called when watchdog device is written to * @file: file structure * @buf: user buffer with data * @len: amount to data written * @ppos: position in file * * returns the number of successfully processed characters, which is always * the number of bytes passed to this function * * wdrtas_write processes all the data given to it and looks for the magic * character 'V'. This character allows the watchdog device to be closed * properly. */ static ssize_t wdrtas_write(struct file *file, const char __user *buf, size_t len, loff_t *ppos) { int i; char c; if (!len) goto out; if (!wdrtas_nowayout) { wdrtas_expect_close = 0; /* look for 'V' */ for (i = 0; i < len; i++) { if (get_user(c, buf + i)) return -EFAULT; /* allow to close device */ if (c == 'V') wdrtas_expect_close = WDRTAS_MAGIC_CHAR; } } wdrtas_timer_keepalive(); out: return len; } /** * wdrtas_ioctl - ioctl function for the watchdog device * @file: file structure * @cmd: command for ioctl * @arg: argument pointer * * returns 0 on success, <0 on failure * * wdrtas_ioctl implements the watchdog API ioctls */ static long wdrtas_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int __user *argp = (void __user *)arg; int i; static const struct watchdog_info wdinfo = { .options = WDRTAS_SUPPORTED_MASK, .firmware_version = 0, .identity = "wdrtas", }; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user(argp, &wdinfo, sizeof(wdinfo))) return -EFAULT; return 0; case WDIOC_GETSTATUS: i = wdrtas_get_status(); return put_user(i, argp); case WDIOC_GETBOOTSTATUS: i = wdrtas_get_boot_status(); return put_user(i, argp); case WDIOC_GETTEMP: if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) return -EOPNOTSUPP; i = wdrtas_get_temperature(); return put_user(i, argp); case WDIOC_SETOPTIONS: if (get_user(i, argp)) return -EFAULT; if (i & WDIOS_DISABLECARD) wdrtas_timer_stop(); if (i & WDIOS_ENABLECARD) { wdrtas_timer_keepalive(); wdrtas_timer_start(); } /* not implemented. Done by H8 if (i & WDIOS_TEMPPANIC) { } */ return 0; case WDIOC_KEEPALIVE: wdrtas_timer_keepalive(); return 0; case WDIOC_SETTIMEOUT: if (get_user(i, argp)) return -EFAULT; if (wdrtas_set_interval(i)) return -EINVAL; wdrtas_timer_keepalive(); if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) wdrtas_interval = i; else wdrtas_interval = wdrtas_get_interval(i); /* fallthrough */ case WDIOC_GETTIMEOUT: return put_user(wdrtas_interval, argp); default: return -ENOTTY; } } /** * wdrtas_open - open function of watchdog device * @inode: inode structure * @file: file structure * * returns 0 on success, -EBUSY if the file has been opened already, <0 on * other failures * * function called when watchdog device is opened */ static int wdrtas_open(struct inode *inode, struct file *file) { /* only open once */ if (atomic_inc_return(&wdrtas_miscdev_open) > 1) { atomic_dec(&wdrtas_miscdev_open); return -EBUSY; } wdrtas_timer_start(); wdrtas_timer_keepalive(); return nonseekable_open(inode, file); } /** * wdrtas_close - close function of watchdog device * @inode: inode structure * @file: file structure * * returns 0 on success * * close function. Always succeeds */ static int wdrtas_close(struct inode *inode, struct file *file) { /* only stop watchdog, if this was announced using 'V' before */ if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR) wdrtas_timer_stop(); else { pr_warn("got unexpected close. Watchdog not stopped.\n"); wdrtas_timer_keepalive(); } wdrtas_expect_close = 0; atomic_dec(&wdrtas_miscdev_open); return 0; } /** * wdrtas_temp_read - gives back the temperature in fahrenheit * @file: file structure * @buf: user buffer * @count: number of bytes to be read * @ppos: position in file * * returns always 1 or -EFAULT in case of user space copy failures, <0 on * other failures * * wdrtas_temp_read gives the temperature to the users by copying this * value as one byte into the user space buffer. The unit is Fahrenheit... */ static ssize_t wdrtas_temp_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { int temperature = 0; temperature = wdrtas_get_temperature(); if (temperature < 0) return temperature; if (copy_to_user(buf, &temperature, 1)) return -EFAULT; return 1; } /** * wdrtas_temp_open - open function of temperature device * @inode: inode structure * @file: file structure * * returns 0 on success, <0 on failure * * function called when temperature device is opened */ static int wdrtas_temp_open(struct inode *inode, struct file *file) { return nonseekable_open(inode, file); } /** * wdrtas_temp_close - close function of temperature device * @inode: inode structure * @file: file structure * * returns 0 on success * * close function. Always succeeds */ static int wdrtas_temp_close(struct inode *inode, struct file *file) { return 0; } /** * wdrtas_reboot - reboot notifier function * @nb: notifier block structure * @code: reboot code * @ptr: unused * * returns NOTIFY_DONE * * wdrtas_reboot stops the watchdog in case of a reboot */ static int wdrtas_reboot(struct notifier_block *this, unsigned long code, void *ptr) { if (code == SYS_DOWN || code == SYS_HALT) wdrtas_timer_stop(); return NOTIFY_DONE; } /*** initialization stuff */ static const struct file_operations wdrtas_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = wdrtas_write, .unlocked_ioctl = wdrtas_ioctl, .open = wdrtas_open, .release = wdrtas_close, }; static struct miscdevice wdrtas_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &wdrtas_fops, }; static const struct file_operations wdrtas_temp_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .read = wdrtas_temp_read, .open = wdrtas_temp_open, .release = wdrtas_temp_close, }; static struct miscdevice wdrtas_tempdev = { .minor = TEMP_MINOR, .name = "temperature", .fops = &wdrtas_temp_fops, }; static struct notifier_block wdrtas_notifier = { .notifier_call = wdrtas_reboot, }; /** * wdrtas_get_tokens - reads in RTAS tokens * * returns 0 on success, <0 on failure * * wdrtas_get_tokens reads in the tokens for the RTAS calls used in * this watchdog driver. It tolerates, if "get-sensor-state" and * "ibm,get-system-parameter" are not available. */ static int wdrtas_get_tokens(void) { wdrtas_token_get_sensor_state = rtas_token("get-sensor-state"); if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) { pr_warn("couldn't get token for get-sensor-state. Trying to continue without temperature support.\n"); } wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter"); if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) { pr_warn("couldn't get token for ibm,get-system-parameter. Trying to continue with a default timeout value of %i seconds.\n", WDRTAS_DEFAULT_INTERVAL); } wdrtas_token_set_indicator = rtas_token("set-indicator"); if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) { pr_err("couldn't get token for set-indicator. Terminating watchdog code.\n"); return -EIO; } wdrtas_token_event_scan = rtas_token("event-scan"); if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) { pr_err("couldn't get token for event-scan. Terminating watchdog code.\n"); return -EIO; } return 0; } /** * wdrtas_unregister_devs - unregisters the misc dev handlers * * wdrtas_register_devs unregisters the watchdog and temperature watchdog * misc devs */ static void wdrtas_unregister_devs(void) { misc_deregister(&wdrtas_miscdev); if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) misc_deregister(&wdrtas_tempdev); } /** * wdrtas_register_devs - registers the misc dev handlers * * returns 0 on success, <0 on failure * * wdrtas_register_devs registers the watchdog and temperature watchdog * misc devs */ static int wdrtas_register_devs(void) { int result; result = misc_register(&wdrtas_miscdev); if (result) { pr_err("couldn't register watchdog misc device. Terminating watchdog code.\n"); return result; } if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) { result = misc_register(&wdrtas_tempdev); if (result) { pr_warn("couldn't register watchdog temperature misc device. Continuing without temperature support.\n"); wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE; } } return 0; } /** * wdrtas_init - init function of the watchdog driver * * returns 0 on success, <0 on failure * * registers the file handlers and the reboot notifier */ static int __init wdrtas_init(void) { if (wdrtas_get_tokens()) return -ENODEV; if (wdrtas_register_devs()) return -ENODEV; if (register_reboot_notifier(&wdrtas_notifier)) { pr_err("could not register reboot notifier. Terminating watchdog code.\n"); wdrtas_unregister_devs(); return -ENODEV; } if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) wdrtas_interval = WDRTAS_DEFAULT_INTERVAL; else wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL); return 0; } /** * wdrtas_exit - exit function of the watchdog driver * * unregisters the file handlers and the reboot notifier */ static void __exit wdrtas_exit(void) { if (!wdrtas_nowayout) wdrtas_timer_stop(); wdrtas_unregister_devs(); unregister_reboot_notifier(&wdrtas_notifier); } module_init(wdrtas_init); module_exit(wdrtas_exit);