Root/target/linux/ar71xx/files/drivers/watchdog/ar71xx_wdt.c

1/*
2 * Driver for the Atheros AR71xx SoC's built-in hardware watchdog timer.
3 *
4 * Copyright (C) 2008 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
32#include <asm/mach-ar71xx/ar71xx.h>
33
34#define DRV_NAME "ar71xx-wdt"
35#define DRV_DESC "Atheros AR71xx hardware watchdog driver"
36#define DRV_VERSION "0.1.0"
37
38#define WDT_TIMEOUT 15 /* seconds */
39
40static int nowayout = WATCHDOG_NOWAYOUT;
41
42#ifdef CONFIG_WATCHDOG_NOWAYOUT
43module_param(nowayout, int, 0);
44MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
45               "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
46#endif
47
48static unsigned long wdt_flags;
49
50#define WDT_FLAGS_BUSY 0
51#define WDT_FLAGS_EXPECT_CLOSE 1
52
53static int wdt_timeout = WDT_TIMEOUT;
54static int boot_status;
55static int max_timeout;
56
57static void inline ar71xx_wdt_keepalive(void)
58{
59    ar71xx_reset_wr(AR71XX_RESET_REG_WDOG, ar71xx_ahb_freq * wdt_timeout);
60}
61
62static void inline ar71xx_wdt_enable(void)
63{
64    printk(KERN_DEBUG DRV_NAME ": enabling watchdog timer\n");
65    ar71xx_wdt_keepalive();
66    ar71xx_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR);
67}
68
69static void inline ar71xx_wdt_disable(void)
70{
71    printk(KERN_DEBUG DRV_NAME ": disabling watchdog timer\n");
72    ar71xx_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE);
73}
74
75static int ar71xx_wdt_set_timeout(int val)
76{
77    if (val < 1 || val > max_timeout)
78        return -EINVAL;
79
80    wdt_timeout = val;
81    ar71xx_wdt_keepalive();
82
83    printk(KERN_DEBUG DRV_NAME ": timeout=%d secs\n", wdt_timeout);
84
85    return 0;
86}
87
88static int ar71xx_wdt_open(struct inode *inode, struct file *file)
89{
90    if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
91        return -EBUSY;
92
93    clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
94
95    ar71xx_wdt_enable();
96
97    return nonseekable_open(inode, file);
98}
99
100static int ar71xx_wdt_release(struct inode *inode, struct file *file)
101{
102    if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags)) {
103        ar71xx_wdt_disable();
104    } else {
105        printk(KERN_CRIT DRV_NAME ": device closed unexpectedly, "
106                    "watchdog timer will not stop!\n");
107    }
108
109    clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
110    clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
111
112    return 0;
113}
114
115static ssize_t ar71xx_wdt_write(struct file *file, const char *data,
116                size_t len, loff_t *ppos)
117{
118        if (len) {
119        if (!nowayout) {
120            size_t i;
121
122            clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
123
124            for (i = 0; i != len; i++) {
125                char c;
126
127                if (get_user(c, data + i))
128                    return -EFAULT;
129
130                if (c == 'V')
131                    set_bit(WDT_FLAGS_EXPECT_CLOSE,
132                        &wdt_flags);
133            }
134        }
135
136        ar71xx_wdt_keepalive();
137    }
138
139    return len;
140}
141
142static struct watchdog_info ar71xx_wdt_info = {
143    .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
144                  WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
145    .firmware_version = 0,
146    .identity = "AR71XX watchdog",
147};
148
149static int ar71xx_wdt_ioctl(struct inode *inode, struct file *file,
150                unsigned int cmd, unsigned long arg)
151{
152    int t;
153    int ret;
154
155    switch (cmd) {
156    case WDIOC_GETSUPPORT:
157        ret = copy_to_user((struct watchdog_info *)arg,
158                   &ar71xx_wdt_info,
159                   sizeof(&ar71xx_wdt_info)) ? -EFAULT : 0;
160        break;
161
162    case WDIOC_GETSTATUS:
163        ret = put_user(0, (int *)arg) ? -EFAULT : 0;
164        break;
165
166    case WDIOC_GETBOOTSTATUS:
167        ret = put_user(boot_status, (int *)arg) ? -EFAULT : 0;
168        break;
169
170    case WDIOC_KEEPALIVE:
171        ar71xx_wdt_keepalive();
172        ret = 0;
173        break;
174
175    case WDIOC_SETTIMEOUT:
176        ret = get_user(t, (int *)arg) ? -EFAULT : 0;
177        if (ret)
178            break;
179
180        ret = ar71xx_wdt_set_timeout(t);
181        if (ret)
182            break;
183
184        /* fallthrough */
185    case WDIOC_GETTIMEOUT:
186        ret = put_user(wdt_timeout, (int *)arg) ? -EFAULT : 0;
187        break;
188
189    default:
190        ret = -ENOTTY;
191        break;
192    }
193
194    return ret;
195}
196
197static const struct file_operations ar71xx_wdt_fops = {
198    .owner = THIS_MODULE,
199    .write = ar71xx_wdt_write,
200    .ioctl = ar71xx_wdt_ioctl,
201    .open = ar71xx_wdt_open,
202    .release = ar71xx_wdt_release,
203};
204
205static struct miscdevice ar71xx_wdt_miscdev = {
206    .minor = WATCHDOG_MINOR,
207    .name = "watchdog",
208    .fops = &ar71xx_wdt_fops,
209};
210
211static int __devinit ar71xx_wdt_probe(struct platform_device *pdev)
212{
213    int ret;
214
215    max_timeout = (0xfffffffful / ar71xx_ahb_freq);
216    wdt_timeout = (max_timeout < WDT_TIMEOUT) ? max_timeout : WDT_TIMEOUT;
217
218    boot_status =
219        (ar71xx_reset_rr(AR71XX_RESET_REG_WDOG_CTRL) & WDOG_CTRL_LAST_RESET) ?
220        WDIOF_CARDRESET : 0;
221
222    ret = misc_register(&ar71xx_wdt_miscdev);
223    if (ret)
224        goto err_out;
225
226    printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
227
228    printk(KERN_DEBUG DRV_NAME ": timeout=%d secs (max=%d)\n",
229                     wdt_timeout, max_timeout);
230
231    return 0;
232
233err_out:
234    return ret;
235}
236
237static int __devexit ar71xx_wdt_remove(struct platform_device *pdev)
238{
239    misc_deregister(&ar71xx_wdt_miscdev);
240    return 0;
241}
242
243static struct platform_driver ar71xx_wdt_driver = {
244    .probe = ar71xx_wdt_probe,
245    .remove = __devexit_p(ar71xx_wdt_remove),
246    .driver = {
247        .name = DRV_NAME,
248        .owner = THIS_MODULE,
249    },
250};
251
252static int __init ar71xx_wdt_init(void)
253{
254    return platform_driver_register(&ar71xx_wdt_driver);
255}
256module_init(ar71xx_wdt_init);
257
258static void __exit ar71xx_wdt_exit(void)
259{
260    platform_driver_unregister(&ar71xx_wdt_driver);
261}
262module_exit(ar71xx_wdt_exit);
263
264MODULE_DESCRIPTION(DRV_DESC);
265MODULE_VERSION(DRV_VERSION);
266MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
267MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
268MODULE_LICENSE("GPL v2");
269MODULE_ALIAS("platform:" DRV_NAME);
270MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
271

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