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Andres Salomon9b0fd112009-12-18 13:02:38 -05001/* Watchdog timer for machines with the CS5535/CS5536 companion chip
Jordan Crouse0b360862008-01-21 10:07:00 -07002 *
3 * Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
Andres Salomon9b0fd112009-12-18 13:02:38 -05004 * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk>
Jordan Crouse0b360862008-01-21 10:07:00 -07005 *
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.
10 */
11
Joe Perches27c766a2012-02-15 15:06:19 -080012#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
Jordan Crouse0b360862008-01-21 10:07:00 -070013
14#include <linux/module.h>
15#include <linux/moduleparam.h>
16#include <linux/types.h>
17#include <linux/miscdevice.h>
18#include <linux/watchdog.h>
19#include <linux/fs.h>
20#include <linux/platform_device.h>
21#include <linux/reboot.h>
Wim Van Sebroeck089ab072008-07-15 11:46:11 +000022#include <linux/uaccess.h>
Jordan Crouse0b360862008-01-21 10:07:00 -070023
Andres Salomon9b0fd112009-12-18 13:02:38 -050024#include <linux/cs5535.h>
Jordan Crouse0b360862008-01-21 10:07:00 -070025
26#define GEODEWDT_HZ 500
27#define GEODEWDT_SCALE 6
28#define GEODEWDT_MAX_SECONDS 131
29
30#define WDT_FLAGS_OPEN 1
31#define WDT_FLAGS_ORPHAN 2
32
33#define DRV_NAME "geodewdt"
34#define WATCHDOG_NAME "Geode GX/LX WDT"
35#define WATCHDOG_TIMEOUT 60
36
37static int timeout = WATCHDOG_TIMEOUT;
38module_param(timeout, int, 0);
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +000039MODULE_PARM_DESC(timeout,
40 "Watchdog timeout in seconds. 1<= timeout <=131, default="
41 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
Jordan Crouse0b360862008-01-21 10:07:00 -070042
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010043static bool nowayout = WATCHDOG_NOWAYOUT;
44module_param(nowayout, bool, 0);
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +000045MODULE_PARM_DESC(nowayout,
46 "Watchdog cannot be stopped once started (default="
47 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Jordan Crouse0b360862008-01-21 10:07:00 -070048
49static struct platform_device *geodewdt_platform_device;
50static unsigned long wdt_flags;
Andres Salomon9b0fd112009-12-18 13:02:38 -050051static struct cs5535_mfgpt_timer *wdt_timer;
Jordan Crouse0b360862008-01-21 10:07:00 -070052static int safe_close;
53
54static void geodewdt_ping(void)
55{
56 /* Stop the counter */
Andres Salomon9b0fd112009-12-18 13:02:38 -050057 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
Jordan Crouse0b360862008-01-21 10:07:00 -070058
59 /* Reset the counter */
Andres Salomon9b0fd112009-12-18 13:02:38 -050060 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
Jordan Crouse0b360862008-01-21 10:07:00 -070061
62 /* Enable the counter */
Andres Salomon9b0fd112009-12-18 13:02:38 -050063 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
Jordan Crouse0b360862008-01-21 10:07:00 -070064}
65
66static void geodewdt_disable(void)
67{
Andres Salomon9b0fd112009-12-18 13:02:38 -050068 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
69 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
Jordan Crouse0b360862008-01-21 10:07:00 -070070}
71
72static int geodewdt_set_heartbeat(int val)
73{
74 if (val < 1 || val > GEODEWDT_MAX_SECONDS)
75 return -EINVAL;
76
Andres Salomon9b0fd112009-12-18 13:02:38 -050077 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
78 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
79 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
80 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
Jordan Crouse0b360862008-01-21 10:07:00 -070081
82 timeout = val;
83 return 0;
84}
85
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +000086static int geodewdt_open(struct inode *inode, struct file *file)
Jordan Crouse0b360862008-01-21 10:07:00 -070087{
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +000088 if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
89 return -EBUSY;
Jordan Crouse0b360862008-01-21 10:07:00 -070090
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +000091 if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
92 __module_get(THIS_MODULE);
Jordan Crouse0b360862008-01-21 10:07:00 -070093
94 geodewdt_ping();
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +000095 return nonseekable_open(inode, file);
Jordan Crouse0b360862008-01-21 10:07:00 -070096}
97
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +000098static int geodewdt_release(struct inode *inode, struct file *file)
Jordan Crouse0b360862008-01-21 10:07:00 -070099{
100 if (safe_close) {
101 geodewdt_disable();
102 module_put(THIS_MODULE);
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000103 } else {
Joe Perches27c766a2012-02-15 15:06:19 -0800104 pr_crit("Unexpected close - watchdog is not stopping\n");
Jordan Crouse0b360862008-01-21 10:07:00 -0700105 geodewdt_ping();
106
107 set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
108 }
109
110 clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
111 safe_close = 0;
112 return 0;
113}
114
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000115static ssize_t geodewdt_write(struct file *file, const char __user *data,
116 size_t len, loff_t *ppos)
Jordan Crouse0b360862008-01-21 10:07:00 -0700117{
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000118 if (len) {
Jordan Crouse0b360862008-01-21 10:07:00 -0700119 if (!nowayout) {
120 size_t i;
121 safe_close = 0;
122
123 for (i = 0; i != len; i++) {
124 char c;
125
126 if (get_user(c, data + i))
127 return -EFAULT;
128
129 if (c == 'V')
130 safe_close = 1;
131 }
132 }
133
134 geodewdt_ping();
135 }
136 return len;
137}
138
Wim Van Sebroeck7275fc82008-09-18 12:26:15 +0000139static long geodewdt_ioctl(struct file *file, unsigned int cmd,
140 unsigned long arg)
Jordan Crouse0b360862008-01-21 10:07:00 -0700141{
142 void __user *argp = (void __user *)arg;
143 int __user *p = argp;
144 int interval;
145
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000146 static const struct watchdog_info ident = {
Jordan Crouse0b360862008-01-21 10:07:00 -0700147 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
148 | WDIOF_MAGICCLOSE,
149 .firmware_version = 1,
150 .identity = WATCHDOG_NAME,
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000151 };
Jordan Crouse0b360862008-01-21 10:07:00 -0700152
Wim Van Sebroeck5eb82492008-07-17 18:08:47 +0000153 switch (cmd) {
Jordan Crouse0b360862008-01-21 10:07:00 -0700154 case WDIOC_GETSUPPORT:
155 return copy_to_user(argp, &ident,
156 sizeof(ident)) ? -EFAULT : 0;
157 break;
158
159 case WDIOC_GETSTATUS:
160 case WDIOC_GETBOOTSTATUS:
161 return put_user(0, p);
162
Jordan Crouse0b360862008-01-21 10:07:00 -0700163 case WDIOC_SETOPTIONS:
164 {
165 int options, ret = -EINVAL;
166
167 if (get_user(options, p))
168 return -EFAULT;
169
170 if (options & WDIOS_DISABLECARD) {
171 geodewdt_disable();
172 ret = 0;
173 }
174
175 if (options & WDIOS_ENABLECARD) {
176 geodewdt_ping();
177 ret = 0;
178 }
179
180 return ret;
181 }
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000182 case WDIOC_KEEPALIVE:
183 geodewdt_ping();
184 return 0;
185
186 case WDIOC_SETTIMEOUT:
187 if (get_user(interval, p))
188 return -EFAULT;
189
190 if (geodewdt_set_heartbeat(interval))
191 return -EINVAL;
192 /* Fall through */
193 case WDIOC_GETTIMEOUT:
194 return put_user(timeout, p);
195
Jordan Crouse0b360862008-01-21 10:07:00 -0700196 default:
197 return -ENOTTY;
198 }
199
200 return 0;
201}
202
203static const struct file_operations geodewdt_fops = {
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000204 .owner = THIS_MODULE,
205 .llseek = no_llseek,
206 .write = geodewdt_write,
Wim Van Sebroeck7275fc82008-09-18 12:26:15 +0000207 .unlocked_ioctl = geodewdt_ioctl,
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000208 .open = geodewdt_open,
209 .release = geodewdt_release,
Jordan Crouse0b360862008-01-21 10:07:00 -0700210};
211
212static struct miscdevice geodewdt_miscdev = {
213 .minor = WATCHDOG_MINOR,
214 .name = "watchdog",
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000215 .fops = &geodewdt_fops,
Jordan Crouse0b360862008-01-21 10:07:00 -0700216};
217
Bill Pemberton2d991a12012-11-19 13:21:41 -0500218static int geodewdt_probe(struct platform_device *dev)
Jordan Crouse0b360862008-01-21 10:07:00 -0700219{
Andres Salomon9b0fd112009-12-18 13:02:38 -0500220 int ret;
Jordan Crouse0b360862008-01-21 10:07:00 -0700221
Andres Salomon9b0fd112009-12-18 13:02:38 -0500222 wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
223 if (!wdt_timer) {
Joe Perches27c766a2012-02-15 15:06:19 -0800224 pr_err("No timers were available\n");
Jordan Crouse0b360862008-01-21 10:07:00 -0700225 return -ENODEV;
226 }
227
Jordan Crouse0b360862008-01-21 10:07:00 -0700228 /* Set up the timer */
229
Andres Salomon9b0fd112009-12-18 13:02:38 -0500230 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
Jordan Crouse0b360862008-01-21 10:07:00 -0700231 GEODEWDT_SCALE | (3 << 8));
232
233 /* Set up comparator 2 to reset when the event fires */
Andres Salomon9b0fd112009-12-18 13:02:38 -0500234 cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
Jordan Crouse0b360862008-01-21 10:07:00 -0700235
236 /* Set up the initial timeout */
237
Andres Salomon9b0fd112009-12-18 13:02:38 -0500238 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
Jordan Crouse0b360862008-01-21 10:07:00 -0700239 timeout * GEODEWDT_HZ);
240
241 ret = misc_register(&geodewdt_miscdev);
242
243 return ret;
244}
245
Bill Pemberton4b12b892012-11-19 13:26:24 -0500246static int geodewdt_remove(struct platform_device *dev)
Jordan Crouse0b360862008-01-21 10:07:00 -0700247{
248 misc_deregister(&geodewdt_miscdev);
249 return 0;
250}
251
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000252static void geodewdt_shutdown(struct platform_device *dev)
Jordan Crouse0b360862008-01-21 10:07:00 -0700253{
254 geodewdt_disable();
255}
256
257static struct platform_driver geodewdt_driver = {
258 .probe = geodewdt_probe,
Bill Pemberton82268712012-11-19 13:21:12 -0500259 .remove = geodewdt_remove,
Jordan Crouse0b360862008-01-21 10:07:00 -0700260 .shutdown = geodewdt_shutdown,
261 .driver = {
262 .owner = THIS_MODULE,
263 .name = DRV_NAME,
264 },
265};
266
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000267static int __init geodewdt_init(void)
Jordan Crouse0b360862008-01-21 10:07:00 -0700268{
269 int ret;
270
271 ret = platform_driver_register(&geodewdt_driver);
272 if (ret)
273 return ret;
274
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +0000275 geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
276 -1, NULL, 0);
Jordan Crouse0b360862008-01-21 10:07:00 -0700277 if (IS_ERR(geodewdt_platform_device)) {
278 ret = PTR_ERR(geodewdt_platform_device);
279 goto err;
280 }
281
282 return 0;
283err:
284 platform_driver_unregister(&geodewdt_driver);
285 return ret;
286}
287
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000288static void __exit geodewdt_exit(void)
Jordan Crouse0b360862008-01-21 10:07:00 -0700289{
290 platform_device_unregister(geodewdt_platform_device);
291 platform_driver_unregister(&geodewdt_driver);
292}
293
294module_init(geodewdt_init);
295module_exit(geodewdt_exit);
296
297MODULE_AUTHOR("Advanced Micro Devices, Inc");
298MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
299MODULE_LICENSE("GPL");
300MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);