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