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f52ac8fe AZ |
1 | /* |
2 | * Watchdog driver for Cirrus Logic EP93xx family of devices. | |
3 | * | |
4 | * Copyright (c) 2004 Ray Lehtiniemi | |
5 | * Copyright (c) 2006 Tower Technologies | |
6 | * Based on ep93xx driver, bits from alim7101_wdt.c | |
7 | * | |
8 | * Authors: Ray Lehtiniemi <rayl@mail.com>, | |
9 | * Alessandro Zummo <a.zummo@towertech.it> | |
10 | * | |
11 | * This file is licensed under the terms of the GNU General Public | |
12 | * License version 2. This program is licensed "as is" without any | |
13 | * warranty of any kind, whether express or implied. | |
14 | * | |
15 | * This watchdog fires after 250msec, which is a too short interval | |
16 | * for us to rely on the user space daemon alone. So we ping the | |
17 | * wdt each ~200msec and eventually stop doing it if the user space | |
18 | * daemon dies. | |
19 | * | |
20 | * TODO: | |
21 | * | |
22 | * - Test last reset from watchdog status | |
23 | * - Add a few missing ioctls | |
24 | */ | |
25 | ||
26 | #include <linux/module.h> | |
27 | #include <linux/fs.h> | |
28 | #include <linux/miscdevice.h> | |
29 | #include <linux/watchdog.h> | |
30 | #include <linux/timer.h> | |
f339e2ac | 31 | #include <linux/uaccess.h> |
a09e64fb | 32 | #include <mach/hardware.h> |
f52ac8fe AZ |
33 | |
34 | #define WDT_VERSION "0.3" | |
35 | #define PFX "ep93xx_wdt: " | |
36 | ||
37 | /* default timeout (secs) */ | |
38 | #define WDT_TIMEOUT 30 | |
39 | ||
40 | static int nowayout = WATCHDOG_NOWAYOUT; | |
41 | static int timeout = WDT_TIMEOUT; | |
42 | ||
43 | static struct timer_list timer; | |
44 | static unsigned long next_heartbeat; | |
45 | static unsigned long wdt_status; | |
46 | static unsigned long boot_status; | |
47 | ||
48 | #define WDT_IN_USE 0 | |
49 | #define WDT_OK_TO_CLOSE 1 | |
50 | ||
51 | #define EP93XX_WDT_REG(x) (EP93XX_WATCHDOG_BASE + (x)) | |
52 | #define EP93XX_WDT_WATCHDOG EP93XX_WDT_REG(0x00) | |
53 | #define EP93XX_WDT_WDSTATUS EP93XX_WDT_REG(0x04) | |
54 | ||
55 | /* reset the wdt every ~200ms */ | |
56 | #define WDT_INTERVAL (HZ/5) | |
57 | ||
58 | static void wdt_enable(void) | |
59 | { | |
60 | __raw_writew(0xaaaa, EP93XX_WDT_WATCHDOG); | |
61 | } | |
62 | ||
63 | static void wdt_disable(void) | |
64 | { | |
65 | __raw_writew(0xaa55, EP93XX_WDT_WATCHDOG); | |
66 | } | |
67 | ||
68 | static inline void wdt_ping(void) | |
69 | { | |
70 | __raw_writew(0x5555, EP93XX_WDT_WATCHDOG); | |
71 | } | |
72 | ||
73 | static void wdt_startup(void) | |
74 | { | |
75 | next_heartbeat = jiffies + (timeout * HZ); | |
76 | ||
77 | wdt_enable(); | |
78 | mod_timer(&timer, jiffies + WDT_INTERVAL); | |
79 | } | |
80 | ||
81 | static void wdt_shutdown(void) | |
82 | { | |
83 | del_timer_sync(&timer); | |
84 | wdt_disable(); | |
85 | } | |
86 | ||
87 | static void wdt_keepalive(void) | |
88 | { | |
89 | /* user land ping */ | |
90 | next_heartbeat = jiffies + (timeout * HZ); | |
91 | } | |
92 | ||
93 | static int ep93xx_wdt_open(struct inode *inode, struct file *file) | |
94 | { | |
95 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) | |
96 | return -EBUSY; | |
97 | ||
98 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
99 | ||
100 | wdt_startup(); | |
101 | ||
102 | return nonseekable_open(inode, file); | |
103 | } | |
104 | ||
105 | static ssize_t | |
106 | ep93xx_wdt_write(struct file *file, const char __user *data, size_t len, | |
107 | loff_t *ppos) | |
108 | { | |
f52ac8fe AZ |
109 | if (len) { |
110 | if (!nowayout) { | |
111 | size_t i; | |
112 | ||
113 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
114 | ||
115 | for (i = 0; i != len; i++) { | |
116 | char c; | |
117 | ||
118 | if (get_user(c, data + i)) | |
119 | return -EFAULT; | |
120 | ||
121 | if (c == 'V') | |
122 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
123 | else | |
124 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
125 | } | |
126 | } | |
127 | wdt_keepalive(); | |
128 | } | |
129 | ||
130 | return len; | |
131 | } | |
132 | ||
133 | static struct watchdog_info ident = { | |
134 | .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE, | |
135 | .identity = "EP93xx Watchdog", | |
136 | }; | |
137 | ||
f339e2ac AC |
138 | static long ep93xx_wdt_ioctl(struct file *file, |
139 | unsigned int cmd, unsigned long arg) | |
f52ac8fe | 140 | { |
795b89d2 | 141 | int ret = -ENOTTY; |
f52ac8fe AZ |
142 | |
143 | switch (cmd) { | |
144 | case WDIOC_GETSUPPORT: | |
145 | ret = copy_to_user((struct watchdog_info __user *)arg, &ident, | |
146 | sizeof(ident)) ? -EFAULT : 0; | |
147 | break; | |
148 | ||
149 | case WDIOC_GETSTATUS: | |
150 | ret = put_user(0, (int __user *)arg); | |
151 | break; | |
152 | ||
153 | case WDIOC_GETBOOTSTATUS: | |
154 | ret = put_user(boot_status, (int __user *)arg); | |
155 | break; | |
156 | ||
f52ac8fe AZ |
157 | case WDIOC_KEEPALIVE: |
158 | wdt_keepalive(); | |
159 | ret = 0; | |
160 | break; | |
0c06090c WVS |
161 | |
162 | case WDIOC_GETTIMEOUT: | |
163 | /* actually, it is 0.250 seconds.... */ | |
164 | ret = put_user(1, (int __user *)arg); | |
165 | break; | |
f52ac8fe AZ |
166 | } |
167 | return ret; | |
168 | } | |
169 | ||
170 | static int ep93xx_wdt_release(struct inode *inode, struct file *file) | |
171 | { | |
172 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) | |
173 | wdt_shutdown(); | |
174 | else | |
f339e2ac AC |
175 | printk(KERN_CRIT PFX |
176 | "Device closed unexpectedly - timer will not stop\n"); | |
f52ac8fe AZ |
177 | |
178 | clear_bit(WDT_IN_USE, &wdt_status); | |
179 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
180 | ||
181 | return 0; | |
182 | } | |
183 | ||
62322d25 | 184 | static const struct file_operations ep93xx_wdt_fops = { |
f52ac8fe AZ |
185 | .owner = THIS_MODULE, |
186 | .write = ep93xx_wdt_write, | |
f339e2ac | 187 | .unlocked_ioctl = ep93xx_wdt_ioctl, |
f52ac8fe AZ |
188 | .open = ep93xx_wdt_open, |
189 | .release = ep93xx_wdt_release, | |
190 | }; | |
191 | ||
192 | static struct miscdevice ep93xx_wdt_miscdev = { | |
193 | .minor = WATCHDOG_MINOR, | |
194 | .name = "watchdog", | |
195 | .fops = &ep93xx_wdt_fops, | |
196 | }; | |
197 | ||
198 | static void ep93xx_timer_ping(unsigned long data) | |
199 | { | |
200 | if (time_before(jiffies, next_heartbeat)) | |
201 | wdt_ping(); | |
202 | ||
203 | /* Re-set the timer interval */ | |
204 | mod_timer(&timer, jiffies + WDT_INTERVAL); | |
205 | } | |
206 | ||
207 | static int __init ep93xx_wdt_init(void) | |
208 | { | |
209 | int err; | |
210 | ||
211 | err = misc_register(&ep93xx_wdt_miscdev); | |
212 | ||
213 | boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0; | |
214 | ||
215 | printk(KERN_INFO PFX "EP93XX watchdog, driver version " | |
216 | WDT_VERSION "%s\n", | |
217 | (__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08) | |
218 | ? " (nCS1 disable detected)" : ""); | |
219 | ||
220 | if (timeout < 1 || timeout > 3600) { | |
221 | timeout = WDT_TIMEOUT; | |
222 | printk(KERN_INFO PFX | |
223 | "timeout value must be 1<=x<=3600, using %d\n", | |
224 | timeout); | |
225 | } | |
226 | ||
227 | setup_timer(&timer, ep93xx_timer_ping, 1); | |
228 | return err; | |
229 | } | |
230 | ||
231 | static void __exit ep93xx_wdt_exit(void) | |
232 | { | |
233 | wdt_shutdown(); | |
234 | misc_deregister(&ep93xx_wdt_miscdev); | |
235 | } | |
236 | ||
237 | module_init(ep93xx_wdt_init); | |
238 | module_exit(ep93xx_wdt_exit); | |
239 | ||
240 | module_param(nowayout, int, 0); | |
241 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); | |
242 | ||
243 | module_param(timeout, int, 0); | |
f339e2ac AC |
244 | MODULE_PARM_DESC(timeout, |
245 | "Watchdog timeout in seconds. (1<=timeout<=3600, default=" | |
246 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
f52ac8fe AZ |
247 | |
248 | MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>," | |
249 | "Alessandro Zummo <a.zummo@towertech.it>"); | |
250 | MODULE_DESCRIPTION("EP93xx Watchdog"); | |
251 | MODULE_LICENSE("GPL"); | |
252 | MODULE_VERSION(WDT_VERSION); | |
253 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |