1 /*
2 * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
3 *
4 * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
5 * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
6 *
7 * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
8 * Author: Deepak Saxena <dsaxena@plexity.net>
9 * Copyright 2004 (c) MontaVista, Software, Inc.
10 *
11 * which again was based on sa1100 driver,
12 * Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
13 *
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License version 2 as published
16 * by the Free Software Foundation.
17 *
18 */
19
20 #include <linux/bitops.h>
21 #include <linux/errno.h>
22 #include <linux/fs.h>
23 #include <linux/init.h>
24 #include <linux/kernel.h>
25 #include <linux/miscdevice.h>
26 #include <linux/module.h>
27 #include <linux/moduleparam.h>
28 #include <linux/platform_device.h>
29 #include <linux/types.h>
30 #include <linux/watchdog.h>
31 #include <linux/clk.h>
32 #include <linux/err.h>
33
34 #include <asm/mach-ath79/ath79.h>
35 #include <asm/mach-ath79/ar71xx_regs.h>
36
37 #define DRIVER_NAME "ath79-wdt"
38
39 #define WDT_TIMEOUT 15 /* seconds */
40
41 #define WDOG_CTRL_LAST_RESET BIT(31)
42 #define WDOG_CTRL_ACTION_MASK 3
43 #define WDOG_CTRL_ACTION_NONE 0 /* no action */
44 #define WDOG_CTRL_ACTION_GPI 1 /* general purpose interrupt */
45 #define WDOG_CTRL_ACTION_NMI 2 /* NMI */
46 #define WDOG_CTRL_ACTION_FCR 3 /* full chip reset */
47
48 static int nowayout = WATCHDOG_NOWAYOUT;
49 module_param(nowayout, int, 0);
50 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
51 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
52
53 static int timeout = WDT_TIMEOUT;
54 module_param(timeout, int, 0);
55 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
56 "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");
57
58 static unsigned long wdt_flags;
59
60 #define WDT_FLAGS_BUSY 0
61 #define WDT_FLAGS_EXPECT_CLOSE 1
62
63 static struct clk *wdt_clk;
64 static unsigned long wdt_freq;
65 static int boot_status;
66 static int max_timeout;
67
ath79_wdt_keepalive(void)68 static inline void ath79_wdt_keepalive(void)
69 {
70 ath79_reset_wr(AR71XX_RESET_REG_WDOG, wdt_freq * timeout);
71 }
72
ath79_wdt_enable(void)73 static inline void ath79_wdt_enable(void)
74 {
75 ath79_wdt_keepalive();
76 ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR);
77 }
78
ath79_wdt_disable(void)79 static inline void ath79_wdt_disable(void)
80 {
81 ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE);
82 }
83
ath79_wdt_set_timeout(int val)84 static int ath79_wdt_set_timeout(int val)
85 {
86 if (val < 1 || val > max_timeout)
87 return -EINVAL;
88
89 timeout = val;
90 ath79_wdt_keepalive();
91
92 return 0;
93 }
94
ath79_wdt_open(struct inode * inode,struct file * file)95 static int ath79_wdt_open(struct inode *inode, struct file *file)
96 {
97 if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
98 return -EBUSY;
99
100 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
101 ath79_wdt_enable();
102
103 return nonseekable_open(inode, file);
104 }
105
ath79_wdt_release(struct inode * inode,struct file * file)106 static int ath79_wdt_release(struct inode *inode, struct file *file)
107 {
108 if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
109 ath79_wdt_disable();
110 else {
111 pr_crit(DRIVER_NAME ": device closed unexpectedly, "
112 "watchdog timer will not stop!\n");
113 ath79_wdt_keepalive();
114 }
115
116 clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
117 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
118
119 return 0;
120 }
121
ath79_wdt_write(struct file * file,const char * data,size_t len,loff_t * ppos)122 static ssize_t ath79_wdt_write(struct file *file, const char *data,
123 size_t len, loff_t *ppos)
124 {
125 if (len) {
126 if (!nowayout) {
127 size_t i;
128
129 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
130
131 for (i = 0; i != len; i++) {
132 char c;
133
134 if (get_user(c, data + i))
135 return -EFAULT;
136
137 if (c == 'V')
138 set_bit(WDT_FLAGS_EXPECT_CLOSE,
139 &wdt_flags);
140 }
141 }
142
143 ath79_wdt_keepalive();
144 }
145
146 return len;
147 }
148
149 static const struct watchdog_info ath79_wdt_info = {
150 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
151 WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
152 .firmware_version = 0,
153 .identity = "ATH79 watchdog",
154 };
155
ath79_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)156 static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
157 unsigned long arg)
158 {
159 void __user *argp = (void __user *)arg;
160 int __user *p = argp;
161 int err;
162 int t;
163
164 switch (cmd) {
165 case WDIOC_GETSUPPORT:
166 err = copy_to_user(argp, &ath79_wdt_info,
167 sizeof(ath79_wdt_info)) ? -EFAULT : 0;
168 break;
169
170 case WDIOC_GETSTATUS:
171 err = put_user(0, p);
172 break;
173
174 case WDIOC_GETBOOTSTATUS:
175 err = put_user(boot_status, p);
176 break;
177
178 case WDIOC_KEEPALIVE:
179 ath79_wdt_keepalive();
180 err = 0;
181 break;
182
183 case WDIOC_SETTIMEOUT:
184 err = get_user(t, p);
185 if (err)
186 break;
187
188 err = ath79_wdt_set_timeout(t);
189 if (err)
190 break;
191
192 /* fallthrough */
193 case WDIOC_GETTIMEOUT:
194 err = put_user(timeout, p);
195 break;
196
197 default:
198 err = -ENOTTY;
199 break;
200 }
201
202 return err;
203 }
204
205 static const struct file_operations ath79_wdt_fops = {
206 .owner = THIS_MODULE,
207 .llseek = no_llseek,
208 .write = ath79_wdt_write,
209 .unlocked_ioctl = ath79_wdt_ioctl,
210 .open = ath79_wdt_open,
211 .release = ath79_wdt_release,
212 };
213
214 static struct miscdevice ath79_wdt_miscdev = {
215 .minor = WATCHDOG_MINOR,
216 .name = "watchdog",
217 .fops = &ath79_wdt_fops,
218 };
219
ath79_wdt_probe(struct platform_device * pdev)220 static int __devinit ath79_wdt_probe(struct platform_device *pdev)
221 {
222 u32 ctrl;
223 int err;
224
225 wdt_clk = clk_get(&pdev->dev, "wdt");
226 if (IS_ERR(wdt_clk))
227 return PTR_ERR(wdt_clk);
228
229 err = clk_enable(wdt_clk);
230 if (err)
231 goto err_clk_put;
232
233 wdt_freq = clk_get_rate(wdt_clk);
234 if (!wdt_freq) {
235 err = -EINVAL;
236 goto err_clk_disable;
237 }
238
239 max_timeout = (0xfffffffful / wdt_freq);
240 if (timeout < 1 || timeout > max_timeout) {
241 timeout = max_timeout;
242 dev_info(&pdev->dev,
243 "timeout value must be 0 < timeout < %d, using %d\n",
244 max_timeout, timeout);
245 }
246
247 ctrl = ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
248 boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;
249
250 err = misc_register(&ath79_wdt_miscdev);
251 if (err) {
252 dev_err(&pdev->dev,
253 "unable to register misc device, err=%d\n", err);
254 goto err_clk_disable;
255 }
256
257 return 0;
258
259 err_clk_disable:
260 clk_disable(wdt_clk);
261 err_clk_put:
262 clk_put(wdt_clk);
263 return err;
264 }
265
ath79_wdt_remove(struct platform_device * pdev)266 static int __devexit ath79_wdt_remove(struct platform_device *pdev)
267 {
268 misc_deregister(&ath79_wdt_miscdev);
269 clk_disable(wdt_clk);
270 clk_put(wdt_clk);
271 return 0;
272 }
273
ath97_wdt_shutdown(struct platform_device * pdev)274 static void ath97_wdt_shutdown(struct platform_device *pdev)
275 {
276 ath79_wdt_disable();
277 }
278
279 static struct platform_driver ath79_wdt_driver = {
280 .remove = __devexit_p(ath79_wdt_remove),
281 .shutdown = ath97_wdt_shutdown,
282 .driver = {
283 .name = DRIVER_NAME,
284 .owner = THIS_MODULE,
285 },
286 };
287
ath79_wdt_init(void)288 static int __init ath79_wdt_init(void)
289 {
290 return platform_driver_probe(&ath79_wdt_driver, ath79_wdt_probe);
291 }
292 module_init(ath79_wdt_init);
293
ath79_wdt_exit(void)294 static void __exit ath79_wdt_exit(void)
295 {
296 platform_driver_unregister(&ath79_wdt_driver);
297 }
298 module_exit(ath79_wdt_exit);
299
300 MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
301 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
302 MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
303 MODULE_LICENSE("GPL v2");
304 MODULE_ALIAS("platform:" DRIVER_NAME);
305 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
306