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16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/types.h>
19#include <linux/kernel.h>
20#include <linux/fs.h>
21#include <linux/miscdevice.h>
22#include <linux/watchdog.h>
23#include <linux/init.h>
24#include <linux/bitops.h>
25#include <linux/uaccess.h>
26#include <mach/hardware.h>
27
28static int nowayout = WATCHDOG_NOWAYOUT;
29static int heartbeat = 60;
30static unsigned long wdt_status;
31static unsigned long boot_status;
32static DEFINE_SPINLOCK(wdt_lock);
33
34#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
35
36#define WDT_IN_USE 0
37#define WDT_OK_TO_CLOSE 1
38
39static void wdt_enable(void)
40{
41 spin_lock(&wdt_lock);
42 *IXP4XX_OSWK = IXP4XX_WDT_KEY;
43 *IXP4XX_OSWE = 0;
44 *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
45 *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
46 *IXP4XX_OSWK = 0;
47 spin_unlock(&wdt_lock);
48}
49
50static void wdt_disable(void)
51{
52 spin_lock(&wdt_lock);
53 *IXP4XX_OSWK = IXP4XX_WDT_KEY;
54 *IXP4XX_OSWE = 0;
55 *IXP4XX_OSWK = 0;
56 spin_unlock(&wdt_lock);
57}
58
59static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
60{
61 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
62 return -EBUSY;
63
64 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
65 wdt_enable();
66 return nonseekable_open(inode, file);
67}
68
69static ssize_t
70ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
71{
72 if (len) {
73 if (!nowayout) {
74 size_t i;
75
76 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
77
78 for (i = 0; i != len; i++) {
79 char c;
80
81 if (get_user(c, data + i))
82 return -EFAULT;
83 if (c == 'V')
84 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
85 }
86 }
87 wdt_enable();
88 }
89 return len;
90}
91
92static struct watchdog_info ident = {
93 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
94 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
95 .identity = "IXP4xx Watchdog",
96};
97
98
99static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
100 unsigned long arg)
101{
102 int ret = -ENOTTY;
103 int time;
104
105 switch (cmd) {
106 case WDIOC_GETSUPPORT:
107 ret = copy_to_user((struct watchdog_info *)arg, &ident,
108 sizeof(ident)) ? -EFAULT : 0;
109 break;
110
111 case WDIOC_GETSTATUS:
112 ret = put_user(0, (int *)arg);
113 break;
114
115 case WDIOC_GETBOOTSTATUS:
116 ret = put_user(boot_status, (int *)arg);
117 break;
118
119 case WDIOC_KEEPALIVE:
120 wdt_enable();
121 ret = 0;
122 break;
123
124 case WDIOC_SETTIMEOUT:
125 ret = get_user(time, (int *)arg);
126 if (ret)
127 break;
128
129 if (time <= 0 || time > 60) {
130 ret = -EINVAL;
131 break;
132 }
133
134 heartbeat = time;
135 wdt_enable();
136
137
138 case WDIOC_GETTIMEOUT:
139 ret = put_user(heartbeat, (int *)arg);
140 break;
141 }
142 return ret;
143}
144
145static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
146{
147 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
148 wdt_disable();
149 else
150 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
151 "timer will not stop\n");
152 clear_bit(WDT_IN_USE, &wdt_status);
153 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
154
155 return 0;
156}
157
158
159static const struct file_operations ixp4xx_wdt_fops = {
160 .owner = THIS_MODULE,
161 .llseek = no_llseek,
162 .write = ixp4xx_wdt_write,
163 .unlocked_ioctl = ixp4xx_wdt_ioctl,
164 .open = ixp4xx_wdt_open,
165 .release = ixp4xx_wdt_release,
166};
167
168static struct miscdevice ixp4xx_wdt_miscdev = {
169 .minor = WATCHDOG_MINOR,
170 .name = "watchdog",
171 .fops = &ixp4xx_wdt_fops,
172};
173
174static int __init ixp4xx_wdt_init(void)
175{
176 int ret;
177
178 if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
179 printk(KERN_ERR "IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected"
180 " - watchdog disabled\n");
181
182 return -ENODEV;
183 }
184 spin_lock_init(&wdt_lock);
185 boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
186 WDIOF_CARDRESET : 0;
187 ret = misc_register(&ixp4xx_wdt_miscdev);
188 if (ret == 0)
189 printk(KERN_INFO "IXP4xx Watchdog Timer: heartbeat %d sec\n",
190 heartbeat);
191 return ret;
192}
193
194static void __exit ixp4xx_wdt_exit(void)
195{
196 misc_deregister(&ixp4xx_wdt_miscdev);
197}
198
199
200module_init(ixp4xx_wdt_init);
201module_exit(ixp4xx_wdt_exit);
202
203MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
204MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
205
206module_param(heartbeat, int, 0);
207MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
208
209module_param(nowayout, int, 0);
210MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
211
212MODULE_LICENSE("GPL");
213MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
214
215
