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Sylver Bruneau22ac9232008-06-26 10:47:45 +02001/*
2 * drivers/watchdog/orion5x_wdt.c
3 *
4 * Watchdog driver for Orion5x processors
5 *
6 * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
7 *
8 * This file is licensed under the terms of the GNU General Public
9 * License version 2. This program is licensed "as is" without any
10 * warranty of any kind, whether express or implied.
11 */
12
13#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/fs.h>
18#include <linux/miscdevice.h>
19#include <linux/watchdog.h>
20#include <linux/init.h>
21#include <linux/uaccess.h>
22#include <linux/io.h>
Wim Van Sebroeck6d0f0df2008-10-02 09:32:45 +000023#include <linux/spinlock.h>
Sylver Bruneau22ac9232008-06-26 10:47:45 +020024
25/*
26 * Watchdog timer block registers.
27 */
28#define TIMER_CTRL (TIMER_VIRT_BASE + 0x0000)
29#define WDT_EN 0x0010
30#define WDT_VAL (TIMER_VIRT_BASE + 0x0024)
31
32#define WDT_MAX_DURATION (0xffffffff / ORION5X_TCLK)
33#define WDT_IN_USE 0
34#define WDT_OK_TO_CLOSE 1
35
36static int nowayout = WATCHDOG_NOWAYOUT;
37static int heartbeat = WDT_MAX_DURATION; /* (seconds) */
38static unsigned long wdt_status;
Wim Van Sebroeck6d0f0df2008-10-02 09:32:45 +000039static spinlock_t wdt_lock;
Sylver Bruneau22ac9232008-06-26 10:47:45 +020040
41static void wdt_enable(void)
42{
43 u32 reg;
44
Wim Van Sebroeck6d0f0df2008-10-02 09:32:45 +000045 spin_lock(&wdt_lock);
46
Sylver Bruneau22ac9232008-06-26 10:47:45 +020047 /* Set watchdog duration */
48 writel(ORION5X_TCLK * heartbeat, WDT_VAL);
49
50 /* Clear watchdog timer interrupt */
51 reg = readl(BRIDGE_CAUSE);
52 reg &= ~WDT_INT_REQ;
53 writel(reg, BRIDGE_CAUSE);
54
55 /* Enable watchdog timer */
56 reg = readl(TIMER_CTRL);
57 reg |= WDT_EN;
58 writel(reg, TIMER_CTRL);
59
60 /* Enable reset on watchdog */
61 reg = readl(CPU_RESET_MASK);
62 reg |= WDT_RESET;
63 writel(reg, CPU_RESET_MASK);
Wim Van Sebroeck6d0f0df2008-10-02 09:32:45 +000064
65 spin_unlock(&wdt_lock);
Sylver Bruneau22ac9232008-06-26 10:47:45 +020066}
67
68static void wdt_disable(void)
69{
70 u32 reg;
71
Wim Van Sebroeck6d0f0df2008-10-02 09:32:45 +000072 spin_lock(&wdt_lock);
73
Sylver Bruneau22ac9232008-06-26 10:47:45 +020074 /* Disable reset on watchdog */
75 reg = readl(CPU_RESET_MASK);
76 reg &= ~WDT_RESET;
77 writel(reg, CPU_RESET_MASK);
78
79 /* Disable watchdog timer */
80 reg = readl(TIMER_CTRL);
81 reg &= ~WDT_EN;
82 writel(reg, TIMER_CTRL);
Wim Van Sebroeck6d0f0df2008-10-02 09:32:45 +000083
84 spin_unlock(&wdt_lock);
85}
86
87static int orion5x_wdt_get_timeleft(int *time_left)
88{
89 spin_lock(&wdt_lock);
90 *time_left = readl(WDT_VAL) / ORION5X_TCLK;
91 spin_unlock(&wdt_lock);
92 return 0;
Sylver Bruneau22ac9232008-06-26 10:47:45 +020093}
94
95static int orion5x_wdt_open(struct inode *inode, struct file *file)
96{
97 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
98 return -EBUSY;
99 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
100 wdt_enable();
101 return nonseekable_open(inode, file);
102}
103
Sylver Bruneau22ac9232008-06-26 10:47:45 +0200104static ssize_t orion5x_wdt_write(struct file *file, const char *data,
105 size_t len, loff_t *ppos)
106{
107 if (len) {
108 if (!nowayout) {
109 size_t i;
110
111 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
112 for (i = 0; i != len; i++) {
113 char c;
114
115 if (get_user(c, data + i))
116 return -EFAULT;
117 if (c == 'V')
118 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
119 }
120 }
121 wdt_enable();
122 }
123 return len;
124}
125
126static struct watchdog_info ident = {
127 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
128 WDIOF_KEEPALIVEPING,
129 .identity = "Orion5x Watchdog",
130};
131
132
133static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
134 unsigned long arg)
135{
136 int ret = -ENOTTY;
137 int time;
138
139 switch (cmd) {
140 case WDIOC_GETSUPPORT:
141 ret = copy_to_user((struct watchdog_info *)arg, &ident,
142 sizeof(ident)) ? -EFAULT : 0;
143 break;
144
145 case WDIOC_GETSTATUS:
146 case WDIOC_GETBOOTSTATUS:
147 ret = put_user(0, (int *)arg);
148 break;
149
150 case WDIOC_KEEPALIVE:
151 wdt_enable();
152 ret = 0;
153 break;
154
155 case WDIOC_SETTIMEOUT:
156 ret = get_user(time, (int *)arg);
157 if (ret)
158 break;
159
160 if (time <= 0 || time > WDT_MAX_DURATION) {
161 ret = -EINVAL;
162 break;
163 }
164 heartbeat = time;
165 wdt_enable();
166 /* Fall through */
167
168 case WDIOC_GETTIMEOUT:
169 ret = put_user(heartbeat, (int *)arg);
170 break;
171
172 case WDIOC_GETTIMELEFT:
173 if (orion5x_wdt_get_timeleft(&time)) {
174 ret = -EINVAL;
175 break;
176 }
177 ret = put_user(time, (int *)arg);
178 break;
179 }
180 return ret;
181}
182
183static int orion5x_wdt_release(struct inode *inode, struct file *file)
184{
185 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
186 wdt_disable();
187 else
188 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
189 "timer will not stop\n");
190 clear_bit(WDT_IN_USE, &wdt_status);
191 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
192
193 return 0;
194}
195
196
197static const struct file_operations orion5x_wdt_fops = {
198 .owner = THIS_MODULE,
199 .llseek = no_llseek,
200 .write = orion5x_wdt_write,
201 .unlocked_ioctl = orion5x_wdt_ioctl,
202 .open = orion5x_wdt_open,
203 .release = orion5x_wdt_release,
204};
205
206static struct miscdevice orion5x_wdt_miscdev = {
207 .minor = WATCHDOG_MINOR,
208 .name = "watchdog",
209 .fops = &orion5x_wdt_fops,
210};
211
212static int __init orion5x_wdt_init(void)
213{
214 int ret;
215
Wim Van Sebroeck6d0f0df2008-10-02 09:32:45 +0000216 spin_lock_init(&wdt_lock);
217
Sylver Bruneau22ac9232008-06-26 10:47:45 +0200218 ret = misc_register(&orion5x_wdt_miscdev);
219 if (ret == 0)
220 printk("Orion5x Watchdog Timer: heartbeat %d sec\n",
221 heartbeat);
222
223 return ret;
224}
225
226static void __exit orion5x_wdt_exit(void)
227{
228 misc_deregister(&orion5x_wdt_miscdev);
229}
230
231module_init(orion5x_wdt_init);
232module_exit(orion5x_wdt_exit);
233
234MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
235MODULE_DESCRIPTION("Orion5x Processor Watchdog");
236
237module_param(heartbeat, int, 0);
238MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is "
239 __MODULE_STRING(WDT_MAX_DURATION) ")");
240
241module_param(nowayout, int, 0);
242MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
243
244MODULE_LICENSE("GPL");
245MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);