Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 1 | /* |
| 2 | * watchdog_core.c |
| 3 | * |
| 4 | * (c) Copyright 2008-2011 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
| 5 | * All Rights Reserved. |
| 6 | * |
| 7 | * (c) Copyright 2008-2011 Wim Van Sebroeck <wim@iguana.be>. |
| 8 | * |
| 9 | * This source code is part of the generic code that can be used |
| 10 | * by all the watchdog timer drivers. |
| 11 | * |
| 12 | * Based on source code of the following authors: |
| 13 | * Matt Domsch <Matt_Domsch@dell.com>, |
| 14 | * Rob Radez <rob@osinvestor.com>, |
| 15 | * Rusty Lynch <rusty@linux.co.intel.com> |
| 16 | * Satyam Sharma <satyam@infradead.org> |
| 17 | * Randy Dunlap <randy.dunlap@oracle.com> |
| 18 | * |
| 19 | * This program is free software; you can redistribute it and/or |
| 20 | * modify it under the terms of the GNU General Public License |
| 21 | * as published by the Free Software Foundation; either version |
| 22 | * 2 of the License, or (at your option) any later version. |
| 23 | * |
| 24 | * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. |
| 25 | * admit liability nor provide warranty for any of this software. |
| 26 | * This material is provided "AS-IS" and at no charge. |
| 27 | */ |
| 28 | |
| 29 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 30 | |
| 31 | #include <linux/module.h> /* For EXPORT_SYMBOL/module stuff/... */ |
| 32 | #include <linux/types.h> /* For standard types */ |
| 33 | #include <linux/errno.h> /* For the -ENODEV/... values */ |
| 34 | #include <linux/kernel.h> /* For printk/panic/... */ |
| 35 | #include <linux/watchdog.h> /* For watchdog specific items */ |
| 36 | #include <linux/init.h> /* For __init/__exit/... */ |
Alan Cox | 45f5fed | 2012-05-10 21:48:59 +0200 | [diff] [blame] | 37 | #include <linux/idr.h> /* For ida_* macros */ |
Alan Cox | d6b469d | 2012-05-11 12:00:20 +0200 | [diff] [blame] | 38 | #include <linux/err.h> /* For IS_ERR macros */ |
Fabio Porcedda | 3048253 | 2013-01-08 11:04:10 +0100 | [diff] [blame] | 39 | #include <linux/of.h> /* For of_get_timeout_sec */ |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 40 | |
Wim Van Sebroeck | 6cfb5aa | 2012-05-21 15:31:06 +0200 | [diff] [blame] | 41 | #include "watchdog_core.h" /* For watchdog_dev_register/... */ |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 42 | |
Alan Cox | 45f5fed | 2012-05-10 21:48:59 +0200 | [diff] [blame] | 43 | static DEFINE_IDA(watchdog_ida); |
Alan Cox | d6b469d | 2012-05-11 12:00:20 +0200 | [diff] [blame] | 44 | static struct class *watchdog_class; |
Alan Cox | 45f5fed | 2012-05-10 21:48:59 +0200 | [diff] [blame] | 45 | |
Fabio Porcedda | 3048253 | 2013-01-08 11:04:10 +0100 | [diff] [blame] | 46 | static void watchdog_check_min_max_timeout(struct watchdog_device *wdd) |
| 47 | { |
| 48 | /* |
| 49 | * Check that we have valid min and max timeout values, if |
| 50 | * not reset them both to 0 (=not used or unknown) |
| 51 | */ |
| 52 | if (wdd->min_timeout > wdd->max_timeout) { |
| 53 | pr_info("Invalid min and max timeout values, resetting to 0!\n"); |
| 54 | wdd->min_timeout = 0; |
| 55 | wdd->max_timeout = 0; |
| 56 | } |
| 57 | } |
| 58 | |
| 59 | /** |
| 60 | * watchdog_init_timeout() - initialize the timeout field |
| 61 | * @timeout_parm: timeout module parameter |
| 62 | * @dev: Device that stores the timeout-sec property |
| 63 | * |
| 64 | * Initialize the timeout field of the watchdog_device struct with either the |
| 65 | * timeout module parameter (if it is valid value) or the timeout-sec property |
| 66 | * (only if it is a valid value and the timeout_parm is out of bounds). |
| 67 | * If none of them are valid then we keep the old value (which should normally |
| 68 | * be the default timeout value. |
| 69 | * |
| 70 | * A zero is returned on success and -EINVAL for failure. |
| 71 | */ |
| 72 | int watchdog_init_timeout(struct watchdog_device *wdd, |
| 73 | unsigned int timeout_parm, struct device *dev) |
| 74 | { |
| 75 | unsigned int t = 0; |
| 76 | int ret = 0; |
| 77 | |
| 78 | watchdog_check_min_max_timeout(wdd); |
| 79 | |
Sachin Kamat | 6ffcff9 | 2013-10-28 14:17:17 +0530 | [diff] [blame] | 80 | /* try to get the timeout module parameter first */ |
Doug Anderson | 2c34d59 | 2013-11-26 10:22:52 -0800 | [diff] [blame] | 81 | if (!watchdog_timeout_invalid(wdd, timeout_parm) && timeout_parm) { |
Fabio Porcedda | 3048253 | 2013-01-08 11:04:10 +0100 | [diff] [blame] | 82 | wdd->timeout = timeout_parm; |
| 83 | return ret; |
| 84 | } |
| 85 | if (timeout_parm) |
| 86 | ret = -EINVAL; |
| 87 | |
| 88 | /* try to get the timeout_sec property */ |
| 89 | if (dev == NULL || dev->of_node == NULL) |
| 90 | return ret; |
| 91 | of_property_read_u32(dev->of_node, "timeout-sec", &t); |
Doug Anderson | 2c34d59 | 2013-11-26 10:22:52 -0800 | [diff] [blame] | 92 | if (!watchdog_timeout_invalid(wdd, t) && t) |
Fabio Porcedda | 3048253 | 2013-01-08 11:04:10 +0100 | [diff] [blame] | 93 | wdd->timeout = t; |
| 94 | else |
| 95 | ret = -EINVAL; |
| 96 | |
| 97 | return ret; |
| 98 | } |
| 99 | EXPORT_SYMBOL_GPL(watchdog_init_timeout); |
| 100 | |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 101 | /** |
| 102 | * watchdog_register_device() - register a watchdog device |
| 103 | * @wdd: watchdog device |
| 104 | * |
| 105 | * Register a watchdog device with the kernel so that the |
| 106 | * watchdog timer can be accessed from userspace. |
| 107 | * |
| 108 | * A zero is returned on success and a negative errno code for |
| 109 | * failure. |
| 110 | */ |
| 111 | int watchdog_register_device(struct watchdog_device *wdd) |
| 112 | { |
Alan Cox | d6b469d | 2012-05-11 12:00:20 +0200 | [diff] [blame] | 113 | int ret, id, devno; |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 114 | |
| 115 | if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL) |
| 116 | return -EINVAL; |
| 117 | |
| 118 | /* Mandatory operations need to be supported */ |
| 119 | if (wdd->ops->start == NULL || wdd->ops->stop == NULL) |
| 120 | return -EINVAL; |
| 121 | |
Fabio Porcedda | 3048253 | 2013-01-08 11:04:10 +0100 | [diff] [blame] | 122 | watchdog_check_min_max_timeout(wdd); |
Wim Van Sebroeck | 3f43f68 | 2011-07-22 19:00:16 +0000 | [diff] [blame] | 123 | |
| 124 | /* |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 125 | * Note: now that all watchdog_device data has been verified, we |
| 126 | * will not check this anymore in other functions. If data gets |
| 127 | * corrupted in a later stage then we expect a kernel panic! |
| 128 | */ |
| 129 | |
Hans de Goede | f4e9c82 | 2012-05-22 11:40:26 +0200 | [diff] [blame] | 130 | mutex_init(&wdd->lock); |
Alan Cox | 45f5fed | 2012-05-10 21:48:59 +0200 | [diff] [blame] | 131 | id = ida_simple_get(&watchdog_ida, 0, MAX_DOGS, GFP_KERNEL); |
| 132 | if (id < 0) |
| 133 | return id; |
| 134 | wdd->id = id; |
| 135 | |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 136 | ret = watchdog_dev_register(wdd); |
| 137 | if (ret) { |
Alan Cox | 45f5fed | 2012-05-10 21:48:59 +0200 | [diff] [blame] | 138 | ida_simple_remove(&watchdog_ida, id); |
| 139 | if (!(id == 0 && ret == -EBUSY)) |
| 140 | return ret; |
| 141 | |
| 142 | /* Retry in case a legacy watchdog module exists */ |
| 143 | id = ida_simple_get(&watchdog_ida, 1, MAX_DOGS, GFP_KERNEL); |
| 144 | if (id < 0) |
| 145 | return id; |
| 146 | wdd->id = id; |
| 147 | |
| 148 | ret = watchdog_dev_register(wdd); |
| 149 | if (ret) { |
| 150 | ida_simple_remove(&watchdog_ida, id); |
| 151 | return ret; |
| 152 | } |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 153 | } |
| 154 | |
Alan Cox | d6b469d | 2012-05-11 12:00:20 +0200 | [diff] [blame] | 155 | devno = wdd->cdev.dev; |
| 156 | wdd->dev = device_create(watchdog_class, wdd->parent, devno, |
| 157 | NULL, "watchdog%d", wdd->id); |
| 158 | if (IS_ERR(wdd->dev)) { |
| 159 | watchdog_dev_unregister(wdd); |
| 160 | ida_simple_remove(&watchdog_ida, id); |
| 161 | ret = PTR_ERR(wdd->dev); |
| 162 | return ret; |
| 163 | } |
| 164 | |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 165 | return 0; |
| 166 | } |
| 167 | EXPORT_SYMBOL_GPL(watchdog_register_device); |
| 168 | |
| 169 | /** |
| 170 | * watchdog_unregister_device() - unregister a watchdog device |
| 171 | * @wdd: watchdog device to unregister |
| 172 | * |
| 173 | * Unregister a watchdog device that was previously successfully |
| 174 | * registered with watchdog_register_device(). |
| 175 | */ |
| 176 | void watchdog_unregister_device(struct watchdog_device *wdd) |
| 177 | { |
| 178 | int ret; |
Wei Yongjun | b232a70 | 2012-09-10 12:41:15 +0800 | [diff] [blame] | 179 | int devno; |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 180 | |
| 181 | if (wdd == NULL) |
| 182 | return; |
| 183 | |
Wei Yongjun | b232a70 | 2012-09-10 12:41:15 +0800 | [diff] [blame] | 184 | devno = wdd->cdev.dev; |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 185 | ret = watchdog_dev_unregister(wdd); |
| 186 | if (ret) |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 187 | pr_err("error unregistering /dev/watchdog (err=%d)\n", ret); |
Alan Cox | d6b469d | 2012-05-11 12:00:20 +0200 | [diff] [blame] | 188 | device_destroy(watchdog_class, devno); |
Alan Cox | 45f5fed | 2012-05-10 21:48:59 +0200 | [diff] [blame] | 189 | ida_simple_remove(&watchdog_ida, wdd->id); |
Alan Cox | d6b469d | 2012-05-11 12:00:20 +0200 | [diff] [blame] | 190 | wdd->dev = NULL; |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 191 | } |
| 192 | EXPORT_SYMBOL_GPL(watchdog_unregister_device); |
| 193 | |
Alan Cox | 45f5fed | 2012-05-10 21:48:59 +0200 | [diff] [blame] | 194 | static int __init watchdog_init(void) |
| 195 | { |
Alan Cox | d6b469d | 2012-05-11 12:00:20 +0200 | [diff] [blame] | 196 | int err; |
| 197 | |
| 198 | watchdog_class = class_create(THIS_MODULE, "watchdog"); |
| 199 | if (IS_ERR(watchdog_class)) { |
| 200 | pr_err("couldn't create class\n"); |
| 201 | return PTR_ERR(watchdog_class); |
| 202 | } |
| 203 | |
| 204 | err = watchdog_dev_init(); |
| 205 | if (err < 0) { |
| 206 | class_destroy(watchdog_class); |
| 207 | return err; |
| 208 | } |
| 209 | |
| 210 | return 0; |
Alan Cox | 45f5fed | 2012-05-10 21:48:59 +0200 | [diff] [blame] | 211 | } |
| 212 | |
| 213 | static void __exit watchdog_exit(void) |
| 214 | { |
| 215 | watchdog_dev_exit(); |
Alan Cox | d6b469d | 2012-05-11 12:00:20 +0200 | [diff] [blame] | 216 | class_destroy(watchdog_class); |
Alan Cox | 45f5fed | 2012-05-10 21:48:59 +0200 | [diff] [blame] | 217 | ida_destroy(&watchdog_ida); |
| 218 | } |
| 219 | |
| 220 | subsys_initcall(watchdog_init); |
| 221 | module_exit(watchdog_exit); |
| 222 | |
Wim Van Sebroeck | 4331604 | 2011-07-22 18:55:18 +0000 | [diff] [blame] | 223 | MODULE_AUTHOR("Alan Cox <alan@lxorguk.ukuu.org.uk>"); |
| 224 | MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>"); |
| 225 | MODULE_DESCRIPTION("WatchDog Timer Driver Core"); |
| 226 | MODULE_LICENSE("GPL"); |