ARM: 7409/1: Do not call flush_cache_user_range with mmap_sem held
[linux/fpc-iii.git] / drivers / watchdog / geodewdt.c
blob9b49b125ad5a3a90bfbce7c5bdd07263822dfac8
1 /* Watchdog timer for machines with the CS5535/CS5536 companion chip
3 * Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
4 * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
13 #include <linux/module.h>
14 #include <linux/moduleparam.h>
15 #include <linux/types.h>
16 #include <linux/miscdevice.h>
17 #include <linux/watchdog.h>
18 #include <linux/fs.h>
19 #include <linux/platform_device.h>
20 #include <linux/reboot.h>
21 #include <linux/uaccess.h>
23 #include <linux/cs5535.h>
25 #define GEODEWDT_HZ 500
26 #define GEODEWDT_SCALE 6
27 #define GEODEWDT_MAX_SECONDS 131
29 #define WDT_FLAGS_OPEN 1
30 #define WDT_FLAGS_ORPHAN 2
32 #define DRV_NAME "geodewdt"
33 #define WATCHDOG_NAME "Geode GX/LX WDT"
34 #define WATCHDOG_TIMEOUT 60
36 static int timeout = WATCHDOG_TIMEOUT;
37 module_param(timeout, int, 0);
38 MODULE_PARM_DESC(timeout,
39 "Watchdog timeout in seconds. 1<= timeout <=131, default="
40 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
42 static int nowayout = WATCHDOG_NOWAYOUT;
43 module_param(nowayout, int, 0);
44 MODULE_PARM_DESC(nowayout,
45 "Watchdog cannot be stopped once started (default="
46 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
48 static struct platform_device *geodewdt_platform_device;
49 static unsigned long wdt_flags;
50 static struct cs5535_mfgpt_timer *wdt_timer;
51 static int safe_close;
53 static void geodewdt_ping(void)
55 /* Stop the counter */
56 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
58 /* Reset the counter */
59 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
61 /* Enable the counter */
62 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
65 static void geodewdt_disable(void)
67 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
68 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
71 static int geodewdt_set_heartbeat(int val)
73 if (val < 1 || val > GEODEWDT_MAX_SECONDS)
74 return -EINVAL;
76 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
77 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
78 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
79 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
81 timeout = val;
82 return 0;
85 static int geodewdt_open(struct inode *inode, struct file *file)
87 if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
88 return -EBUSY;
90 if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
91 __module_get(THIS_MODULE);
93 geodewdt_ping();
94 return nonseekable_open(inode, file);
97 static int geodewdt_release(struct inode *inode, struct file *file)
99 if (safe_close) {
100 geodewdt_disable();
101 module_put(THIS_MODULE);
102 } else {
103 printk(KERN_CRIT "Unexpected close - watchdog is not stopping.\n");
104 geodewdt_ping();
106 set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
109 clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
110 safe_close = 0;
111 return 0;
114 static ssize_t geodewdt_write(struct file *file, const char __user *data,
115 size_t len, loff_t *ppos)
117 if (len) {
118 if (!nowayout) {
119 size_t i;
120 safe_close = 0;
122 for (i = 0; i != len; i++) {
123 char c;
125 if (get_user(c, data + i))
126 return -EFAULT;
128 if (c == 'V')
129 safe_close = 1;
133 geodewdt_ping();
135 return len;
138 static long geodewdt_ioctl(struct file *file, unsigned int cmd,
139 unsigned long arg)
141 void __user *argp = (void __user *)arg;
142 int __user *p = argp;
143 int interval;
145 static const struct watchdog_info ident = {
146 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
147 | WDIOF_MAGICCLOSE,
148 .firmware_version = 1,
149 .identity = WATCHDOG_NAME,
152 switch (cmd) {
153 case WDIOC_GETSUPPORT:
154 return copy_to_user(argp, &ident,
155 sizeof(ident)) ? -EFAULT : 0;
156 break;
158 case WDIOC_GETSTATUS:
159 case WDIOC_GETBOOTSTATUS:
160 return put_user(0, p);
162 case WDIOC_SETOPTIONS:
164 int options, ret = -EINVAL;
166 if (get_user(options, p))
167 return -EFAULT;
169 if (options & WDIOS_DISABLECARD) {
170 geodewdt_disable();
171 ret = 0;
174 if (options & WDIOS_ENABLECARD) {
175 geodewdt_ping();
176 ret = 0;
179 return ret;
181 case WDIOC_KEEPALIVE:
182 geodewdt_ping();
183 return 0;
185 case WDIOC_SETTIMEOUT:
186 if (get_user(interval, p))
187 return -EFAULT;
189 if (geodewdt_set_heartbeat(interval))
190 return -EINVAL;
191 /* Fall through */
192 case WDIOC_GETTIMEOUT:
193 return put_user(timeout, p);
195 default:
196 return -ENOTTY;
199 return 0;
202 static const struct file_operations geodewdt_fops = {
203 .owner = THIS_MODULE,
204 .llseek = no_llseek,
205 .write = geodewdt_write,
206 .unlocked_ioctl = geodewdt_ioctl,
207 .open = geodewdt_open,
208 .release = geodewdt_release,
211 static struct miscdevice geodewdt_miscdev = {
212 .minor = WATCHDOG_MINOR,
213 .name = "watchdog",
214 .fops = &geodewdt_fops,
217 static int __devinit geodewdt_probe(struct platform_device *dev)
219 int ret;
221 wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
222 if (!wdt_timer) {
223 printk(KERN_ERR "geodewdt: No timers were available\n");
224 return -ENODEV;
227 /* Set up the timer */
229 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
230 GEODEWDT_SCALE | (3 << 8));
232 /* Set up comparator 2 to reset when the event fires */
233 cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
235 /* Set up the initial timeout */
237 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
238 timeout * GEODEWDT_HZ);
240 ret = misc_register(&geodewdt_miscdev);
242 return ret;
245 static int __devexit geodewdt_remove(struct platform_device *dev)
247 misc_deregister(&geodewdt_miscdev);
248 return 0;
251 static void geodewdt_shutdown(struct platform_device *dev)
253 geodewdt_disable();
256 static struct platform_driver geodewdt_driver = {
257 .probe = geodewdt_probe,
258 .remove = __devexit_p(geodewdt_remove),
259 .shutdown = geodewdt_shutdown,
260 .driver = {
261 .owner = THIS_MODULE,
262 .name = DRV_NAME,
266 static int __init geodewdt_init(void)
268 int ret;
270 ret = platform_driver_register(&geodewdt_driver);
271 if (ret)
272 return ret;
274 geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
275 -1, NULL, 0);
276 if (IS_ERR(geodewdt_platform_device)) {
277 ret = PTR_ERR(geodewdt_platform_device);
278 goto err;
281 return 0;
282 err:
283 platform_driver_unregister(&geodewdt_driver);
284 return ret;
287 static void __exit geodewdt_exit(void)
289 platform_device_unregister(geodewdt_platform_device);
290 platform_driver_unregister(&geodewdt_driver);
293 module_init(geodewdt_init);
294 module_exit(geodewdt_exit);
296 MODULE_AUTHOR("Advanced Micro Devices, Inc");
297 MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
298 MODULE_LICENSE("GPL");
299 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);