d3be4f831db58a22cee4e868920923ad3bc5612d
[sfrench/cifs-2.6.git] / drivers / watchdog / sa1100_wdt.c
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/clk.h>
26 #include <linux/types.h>
27 #include <linux/kernel.h>
28 #include <linux/fs.h>
29 #include <linux/miscdevice.h>
30 #include <linux/watchdog.h>
31 #include <linux/init.h>
32 #include <linux/io.h>
33 #include <linux/bitops.h>
34 #include <linux/uaccess.h>
35 #include <linux/timex.h>
36
37 #ifdef CONFIG_ARCH_PXA
38 #include <mach/regs-ost.h>
39 #endif
40
41 #include <mach/reset.h>
42 #include <mach/hardware.h>
43
44 static unsigned long oscr_freq;
45 static unsigned long sa1100wdt_users;
46 static unsigned int pre_margin;
47 static int boot_status;
48
49 /*
50  *      Allow only one person to hold it open
51  */
52 static int sa1100dog_open(struct inode *inode, struct file *file)
53 {
54         if (test_and_set_bit(1, &sa1100wdt_users))
55                 return -EBUSY;
56
57         /* Activate SA1100 Watchdog timer */
58         writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
59         writel_relaxed(OSSR_M3, OSSR);
60         writel_relaxed(OWER_WME, OWER);
61         writel_relaxed(readl_relaxed(OIER) | OIER_E3, OIER);
62         return nonseekable_open(inode, file);
63 }
64
65 /*
66  * The watchdog cannot be disabled.
67  *
68  * Previous comments suggested that turning off the interrupt by
69  * clearing OIER[E3] would prevent the watchdog timing out but this
70  * does not appear to be true (at least on the PXA255).
71  */
72 static int sa1100dog_release(struct inode *inode, struct file *file)
73 {
74         pr_crit("Device closed - timer will not stop\n");
75         clear_bit(1, &sa1100wdt_users);
76         return 0;
77 }
78
79 static ssize_t sa1100dog_write(struct file *file, const char __user *data,
80                                                 size_t len, loff_t *ppos)
81 {
82         if (len)
83                 /* Refresh OSMR3 timer. */
84                 writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
85         return len;
86 }
87
88 static const struct watchdog_info ident = {
89         .options        = WDIOF_CARDRESET | WDIOF_SETTIMEOUT
90                                 | WDIOF_KEEPALIVEPING,
91         .identity       = "SA1100/PXA255 Watchdog",
92         .firmware_version       = 1,
93 };
94
95 static long sa1100dog_ioctl(struct file *file, unsigned int cmd,
96                                                         unsigned long arg)
97 {
98         int ret = -ENOTTY;
99         int time;
100         void __user *argp = (void __user *)arg;
101         int __user *p = argp;
102
103         switch (cmd) {
104         case WDIOC_GETSUPPORT:
105                 ret = copy_to_user(argp, &ident,
106                                    sizeof(ident)) ? -EFAULT : 0;
107                 break;
108
109         case WDIOC_GETSTATUS:
110                 ret = put_user(0, p);
111                 break;
112
113         case WDIOC_GETBOOTSTATUS:
114                 ret = put_user(boot_status, p);
115                 break;
116
117         case WDIOC_KEEPALIVE:
118                 writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
119                 ret = 0;
120                 break;
121
122         case WDIOC_SETTIMEOUT:
123                 ret = get_user(time, p);
124                 if (ret)
125                         break;
126
127                 if (time <= 0 || (oscr_freq * (long long)time >= 0xffffffff)) {
128                         ret = -EINVAL;
129                         break;
130                 }
131
132                 pre_margin = oscr_freq * time;
133                 writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3);
134                 /*fall through*/
135
136         case WDIOC_GETTIMEOUT:
137                 ret = put_user(pre_margin / oscr_freq, p);
138                 break;
139         }
140         return ret;
141 }
142
143 static const struct file_operations sa1100dog_fops = {
144         .owner          = THIS_MODULE,
145         .llseek         = no_llseek,
146         .write          = sa1100dog_write,
147         .unlocked_ioctl = sa1100dog_ioctl,
148         .open           = sa1100dog_open,
149         .release        = sa1100dog_release,
150 };
151
152 static struct miscdevice sa1100dog_miscdev = {
153         .minor          = WATCHDOG_MINOR,
154         .name           = "watchdog",
155         .fops           = &sa1100dog_fops,
156 };
157
158 static int margin __initdata = 60;              /* (secs) Default is 1 minute */
159 static struct clk *clk;
160
161 static int __init sa1100dog_init(void)
162 {
163         int ret;
164
165         clk = clk_get(NULL, "OSTIMER0");
166         if (IS_ERR(clk)) {
167                 pr_err("SA1100/PXA2xx Watchdog Timer: clock not found: %d\n",
168                        (int) PTR_ERR(clk));
169                 return PTR_ERR(clk);
170         }
171
172         ret = clk_prepare_enable(clk);
173         if (ret) {
174                 pr_err("SA1100/PXA2xx Watchdog Timer: clock failed to prepare+enable: %d\n",
175                        ret);
176                 goto err;
177         }
178
179         oscr_freq = clk_get_rate(clk);
180
181         /*
182          * Read the reset status, and save it for later.  If
183          * we suspend, RCSR will be cleared, and the watchdog
184          * reset reason will be lost.
185          */
186         boot_status = (reset_status & RESET_STATUS_WATCHDOG) ?
187                                 WDIOF_CARDRESET : 0;
188         pre_margin = oscr_freq * margin;
189
190         ret = misc_register(&sa1100dog_miscdev);
191         if (ret == 0) {
192                 pr_info("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
193                         margin);
194                 return 0;
195         }
196
197         clk_disable_unprepare(clk);
198 err:
199         clk_put(clk);
200         return ret;
201 }
202
203 static void __exit sa1100dog_exit(void)
204 {
205         misc_deregister(&sa1100dog_miscdev);
206         clk_disable_unprepare(clk);
207         clk_put(clk);
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_LICENSE("GPL");