1 /*
2 * Watchdog driver for the SA11x0/PXA2xx
3 *
4 * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
5 * Based on SoftDog driver by Alan Cox <alan@redhat.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Neither Oleg Drokin nor iXcelerator.com admit liability nor provide
13 * warranty for any of this software. This material is provided
14 * "AS-IS" and at no charge.
15 *
16 * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
17 *
18 * 27/11/2000 Initial release
19 */
20 #include <linux/config.h>
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/types.h>
24 #include <linux/kernel.h>
25 #include <linux/fs.h>
26 #include <linux/miscdevice.h>
27 #include <linux/watchdog.h>
28 #include <linux/init.h>
29
30 #ifdef CONFIG_ARCH_PXA
31 #include <asm/arch/pxa-regs.h>
32 #endif
33
34 #include <asm/hardware.h>
35 #include <asm/bitops.h>
36 #include <asm/uaccess.h>
37
38 #define OSCR_FREQ 3686400
39 #define SA1100_CLOSE_MAGIC (0x5afc4453)
40
41 static unsigned long sa1100wdt_users;
42 static int expect_close;
43 static int pre_margin;
44 static int boot_status;
45 #ifdef CONFIG_WATCHDOG_NOWAYOUT
46 static int nowayout = 1;
47 #else
48 static int nowayout = 0;
49 #endif
50
51 /*
52 * Allow only one person to hold it open
53 */
54 static int sa1100dog_open(struct inode *inode, struct file *file)
55 {
56 nonseekable_open(inode, file);
57 if (test_and_set_bit(1,&sa1100wdt_users))
58 return -EBUSY;
59
60 /* Activate SA1100 Watchdog timer */
61 OSMR3 = OSCR + pre_margin;
62 OSSR = OSSR_M3;
63 OWER = OWER_WME;
64 OIER |= OIER_E3;
65 return 0;
66 }
67
68 /*
69 * Shut off the timer.
70 * Lock it in if it's a module and we defined ...NOWAYOUT
71 * Oddly, the watchdog can only be enabled, but we can turn off
72 * the interrupt, which appears to prevent the watchdog timing out.
73 */
74 static int sa1100dog_release(struct inode *inode, struct file *file)
75 {
76 OSMR3 = OSCR + pre_margin;
77
78 if (expect_close == SA1100_CLOSE_MAGIC) {
79 OIER &= ~OIER_E3;
80 } else {
81 printk(KERN_CRIT "WATCHDOG: WDT device closed unexpectedly. WDT will not stop!\n");
82 }
83
84 clear_bit(1, &sa1100wdt_users);
85 expect_close = 0;
86
87 return 0;
88 }
89
90 static ssize_t sa1100dog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
91 {
92 if (len) {
93 if (!nowayout) {
94 size_t i;
95
96 expect_close = 0;
97
98 for (i = 0; i != len; i++) {
99 char c;
100
101 if (get_user(c, data + i))
102 return -EFAULT;
103 if (c == 'V')
104 expect_close = SA1100_CLOSE_MAGIC;
105 }
106 }
107 /* Refresh OSMR3 timer. */
108 OSMR3 = OSCR + pre_margin;
109 }
110
111 return len;
112 }
113
114 static struct watchdog_info ident = {
115 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
116 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
117 .identity = "SA1100 Watchdog",
118 };
119
120 static int sa1100dog_ioctl(struct inode *inode, struct file *file,
121 unsigned int cmd, unsigned long arg)
122 {
123 int ret = -ENOIOCTLCMD;
124 int time;
125
126 switch (cmd) {
127 case WDIOC_GETSUPPORT:
128 ret = copy_to_user((struct watchdog_info *)arg, &ident,
129 sizeof(ident)) ? -EFAULT : 0;
130 break;
131
132 case WDIOC_GETSTATUS:
133 ret = put_user(0, (int *)arg);
134 break;
135
136 case WDIOC_GETBOOTSTATUS:
137 ret = put_user(boot_status, (int *)arg);
138 break;
139
140 case WDIOC_SETTIMEOUT:
141 ret = get_user(time, (int *)arg);
142 if (ret)
143 break;
144
145 if (time <= 0 || time > 255) {
146 ret = -EINVAL;
147 break;
148 }
149
150 pre_margin = OSCR_FREQ * time;
151 OSMR3 = OSCR + pre_margin;
152 /*fall through*/
153
154 case WDIOC_GETTIMEOUT:
155 ret = put_user(pre_margin / OSCR_FREQ, (int *)arg);
156 break;
157
158 case WDIOC_KEEPALIVE:
159 OSMR3 = OSCR + pre_margin;
160 ret = 0;
161 break;
162 }
163 return ret;
164 }
165
166 static struct file_operations sa1100dog_fops =
167 {
168 .owner = THIS_MODULE,
169 .llseek = no_llseek,
170 .write = sa1100dog_write,
171 .ioctl = sa1100dog_ioctl,
172 .open = sa1100dog_open,
173 .release = sa1100dog_release,
174 };
175
176 static struct miscdevice sa1100dog_miscdev =
177 {
178 .minor = WATCHDOG_MINOR,
179 .name = "SA1100/PXA2xx watchdog",
180 .fops = &sa1100dog_fops,
181 };
182
183 static int margin __initdata = 60; /* (secs) Default is 1 minute */
184
185 static int __init sa1100dog_init(void)
186 {
187 int ret;
188
189 /*
190 * Read the reset status, and save it for later. If
191 * we suspend, RCSR will be cleared, and the watchdog
192 * reset reason will be lost.
193 */
194 boot_status = (RCSR & RCSR_WDR) ? WDIOF_CARDRESET : 0;
195 pre_margin = OSCR_FREQ * margin;
196
197 ret = misc_register(&sa1100dog_miscdev);
198 if (ret == 0)
199 printk("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
200 margin);
201
202 return ret;
203 }
204
205 static void __exit sa1100dog_exit(void)
206 {
207 misc_deregister(&sa1100dog_miscdev);
208 }
209
210 module_init(sa1100dog_init);
211 module_exit(sa1100dog_exit);
212
213 MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
214 MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");
215
216 module_param(margin, int, 0);
217 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
218
219 module_param(nowayout, int, 0);
220 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
221
222 MODULE_LICENSE("GPL");
223 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
224
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