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@lxorguk.ukuu.org.uk>
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
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/types.h>
26 #include <linux/kernel.h>
27 #include <linux/fs.h>
28 #include <linux/miscdevice.h>
29 #include <linux/watchdog.h>
30 #include <linux/init.h>
31 #include <linux/io.h>
32 #include <linux/bitops.h>
33 #include <linux/uaccess.h>
34 #include <linux/timex.h>
35
36 #ifdef CONFIG_ARCH_PXA
37 #include <mach/regs-ost.h>
38 #endif
39
40 #include <mach/reset.h>
41 #include <mach/hardware.h>
42
43 static unsigned long oscr_freq;
44 static unsigned long sa1100wdt_users;
45 static unsigned int pre_margin;
46 static int boot_status;
47
48 /*
49 * Allow only one person to hold it open
50 */
sa1100dog_open(struct inode * inode,struct file * file)51 static int sa1100dog_open(struct inode *inode, struct file *file)
52 {
53 if (test_and_set_bit(1, &sa1100wdt_users))
54 return -EBUSY;
55
56 /* Activate SA1100 Watchdog timer */
57 writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
58 writel_relaxed(OSSR_M3, OSSR);
59 writel_relaxed(OWER_WME, OWER);
60 writel_relaxed(readl_relaxed(OIER) | OIER_E3, OIER);
61 return nonseekable_open(inode, file);
62 }
63
64 /*
65 * The watchdog cannot be disabled.
66 *
67 * Previous comments suggested that turning off the interrupt by
68 * clearing OIER[E3] would prevent the watchdog timing out but this
69 * does not appear to be true (at least on the PXA255).
70 */
sa1100dog_release(struct inode * inode,struct file * file)71 static int sa1100dog_release(struct inode *inode, struct file *file)
72 {
73 pr_crit("Device closed - timer will not stop\n");
74 clear_bit(1, &sa1100wdt_users);
75 return 0;
76 }
77
sa1100dog_write(struct file * file,const char __user * data,size_t len,loff_t * ppos)78 static ssize_t sa1100dog_write(struct file *file, const char __user *data,
79 size_t len, loff_t *ppos)
80 {
81 if (len)
82 /* Refresh OSMR3 timer. */
83 writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
84 return len;
85 }
86
87 static const struct watchdog_info ident = {
88 .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT
89 | WDIOF_KEEPALIVEPING,
90 .identity = "SA1100/PXA255 Watchdog",
91 .firmware_version = 1,
92 };
93
sa1100dog_ioctl(struct file * file,unsigned int cmd,unsigned long arg)94 static long sa1100dog_ioctl(struct file *file, unsigned int cmd,
95 unsigned long arg)
96 {
97 int ret = -ENOTTY;
98 int time;
99 void __user *argp = (void __user *)arg;
100 int __user *p = argp;
101
102 switch (cmd) {
103 case WDIOC_GETSUPPORT:
104 ret = copy_to_user(argp, &ident,
105 sizeof(ident)) ? -EFAULT : 0;
106 break;
107
108 case WDIOC_GETSTATUS:
109 ret = put_user(0, p);
110 break;
111
112 case WDIOC_GETBOOTSTATUS:
113 ret = put_user(boot_status, p);
114 break;
115
116 case WDIOC_KEEPALIVE:
117 writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
118 ret = 0;
119 break;
120
121 case WDIOC_SETTIMEOUT:
122 ret = get_user(time, p);
123 if (ret)
124 break;
125
126 if (time <= 0 || (oscr_freq * (long long)time >= 0xffffffff)) {
127 ret = -EINVAL;
128 break;
129 }
130
131 pre_margin = oscr_freq * time;
132 writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
133 /*fall through*/
134
135 case WDIOC_GETTIMEOUT:
136 ret = put_user(pre_margin / oscr_freq, p);
137 break;
138 }
139 return ret;
140 }
141
142 static const struct file_operations sa1100dog_fops = {
143 .owner = THIS_MODULE,
144 .llseek = no_llseek,
145 .write = sa1100dog_write,
146 .unlocked_ioctl = sa1100dog_ioctl,
147 .open = sa1100dog_open,
148 .release = sa1100dog_release,
149 };
150
151 static struct miscdevice sa1100dog_miscdev = {
152 .minor = WATCHDOG_MINOR,
153 .name = "watchdog",
154 .fops = &sa1100dog_fops,
155 };
156
157 static int margin __initdata = 60; /* (secs) Default is 1 minute */
158
sa1100dog_init(void)159 static int __init sa1100dog_init(void)
160 {
161 int ret;
162
163 oscr_freq = get_clock_tick_rate();
164
165 /*
166 * Read the reset status, and save it for later. If
167 * we suspend, RCSR will be cleared, and the watchdog
168 * reset reason will be lost.
169 */
170 boot_status = (reset_status & RESET_STATUS_WATCHDOG) ?
171 WDIOF_CARDRESET : 0;
172 pre_margin = oscr_freq * margin;
173
174 ret = misc_register(&sa1100dog_miscdev);
175 if (ret == 0)
176 pr_info("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
177 margin);
178 return ret;
179 }
180
sa1100dog_exit(void)181 static void __exit sa1100dog_exit(void)
182 {
183 misc_deregister(&sa1100dog_miscdev);
184 }
185
186 module_init(sa1100dog_init);
187 module_exit(sa1100dog_exit);
188
189 MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
190 MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");
191
192 module_param(margin, int, 0);
193 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
194
195 MODULE_LICENSE("GPL");
196