1 files changed, 696 insertions, 0 deletions

diff --git a/drivers/char/watchdog/wdrtas.c b/drivers/char/watchdog/wdrtas.c
new file mode 100644
index 000000000000..619e2ffca33f
--- /dev/null
+++ b/drivers/char/watchdog/wdrtas.c
@@ -0,0 +1,696 @@
+/*
+ * 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.
+ */
+
+#include <linux/config.h>
+#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 <asm/rtas.h>
+#include <asm/uaccess.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");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS_MISCDEV(TEMP_MINOR);
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+static int wdrtas_nowayout = 1;
+#else
+static int wdrtas_nowayout = 0;
+#endif
+
+static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0);
+static char wdrtas_expect_close = 0;
+
+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) ) {
+                printk(KERN_ERR "wdrtas: setting the watchdog to %i "
+                       "timeout failed: %li\n", interval, result);
+                print_msg--;
+        }
+
+        return result;
+}
+
+/**
+ * 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[4];
+
+        result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL,
+                           WDRTAS_SP_SPI, (void *)__pa(&value), 4);
+        if ( (value[0] != 0) || (value[1] != 2) || (value[3] != 0) ||
+             (result < 0) ) {
+                printk(KERN_WARNING "wdrtas: 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_log_scanned_event - logs an event we received during keepalive
+ *
+ * wdrtas_log_scanned_event prints a message to the log buffer dumping
+ * the results of the last event-scan call
+ */
+static void
+wdrtas_log_scanned_event(void)
+{
+        int i;
+
+        for (i = 0; i < WDRTAS_LOGBUFFER_LEN; i += 16)
+                printk(KERN_INFO "wdrtas: dumping event (line %i/%i), data = "
+                       "%02x %02x %02x %02x  %02x %02x %02x %02x   "
+                       "%02x %02x %02x %02x  %02x %02x %02x %02x\n",
+                       (i / 16) + 1, (WDRTAS_LOGBUFFER_LEN / 16),
+                       wdrtas_logbuffer[i + 0], wdrtas_logbuffer[i + 1], 
+                       wdrtas_logbuffer[i + 2], wdrtas_logbuffer[i + 3], 
+                       wdrtas_logbuffer[i + 4], wdrtas_logbuffer[i + 5], 
+                       wdrtas_logbuffer[i + 6], wdrtas_logbuffer[i + 7], 
+                       wdrtas_logbuffer[i + 8], wdrtas_logbuffer[i + 9], 
+                       wdrtas_logbuffer[i + 10], wdrtas_logbuffer[i + 11], 
+                       wdrtas_logbuffer[i + 12], wdrtas_logbuffer[i + 13], 
+                       wdrtas_logbuffer[i + 14], wdrtas_logbuffer[i + 15]);
+}
+
+/**
+ * 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)
+                        printk(KERN_ERR "wdrtas: event-scan failed: %li\n",
+                               result);
+                if (result == 0)
+                        wdrtas_log_scanned_event();
+        } 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)
+{
+        long result;
+        int temperature = 0;
+
+        result = rtas_call(wdrtas_token_get_sensor_state, 2, 2,
+                           (void *)__pa(&temperature),
+                           WDRTAS_THERMAL_SENSOR, 0);
+
+        if (result < 0)
+                printk(KERN_WARNING "wdrtas: reading the thermal sensor "
+                       "faild: %li\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
+ * @inode: inode structure
+ * @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 int
+wdrtas_ioctl(struct inode *inode, struct file *file,
+             unsigned int cmd, unsigned long arg)
+{
+        int __user *argp = (void *)arg;
+        int i;
+        static 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();
+                }
+                if (i & WDIOS_TEMPPANIC) {
+                        /* not implemented. Done by H8 */
+                }
+                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 -ENOIOCTLCMD;
+        }
+}
+
+/**
+ * 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 {
+                printk(KERN_WARNING "wdrtas: 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 struct file_operations wdrtas_fops = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .write          = wdrtas_write,
+        .ioctl          = wdrtas_ioctl,
+        .open           = wdrtas_open,
+        .release        = wdrtas_close,
+};
+
+static struct miscdevice wdrtas_miscdev = {
+        .minor =        WATCHDOG_MINOR,
+        .name =         "watchdog",
+        .fops =         &wdrtas_fops,
+};
+
+static 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 succes, <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) {
+                printk(KERN_WARNING "wdrtas: 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) {
+                printk(KERN_WARNING "wdrtas: 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) {
+                printk(KERN_ERR "wdrtas: 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) {
+                printk(KERN_ERR "wdrtas: 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 succes, <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) {
+                printk(KERN_ERR "wdrtas: 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) {
+                        printk(KERN_WARNING "wdrtas: 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 succes, <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)) {
+                printk(KERN_ERR "wdrtas: 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);