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1da177e4 LT |
1 | /* |
2 | * drivers/watchdog/ixp4xx_wdt.c | |
3 | * | |
4 | * Watchdog driver for Intel IXP4xx network processors | |
5 | * | |
6 | * Author: Deepak Saxena <dsaxena@plexity.net> | |
7 | * | |
8 | * Copyright 2004 (c) MontaVista, Software, Inc. | |
9 | * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> | |
10 | * | |
11 | * This file is licensed under the terms of the GNU General Public | |
12 | * License version 2. This program is licensed "as is" without any | |
13 | * warranty of any kind, whether express or implied. | |
14 | */ | |
15 | ||
16 | #include <linux/config.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/moduleparam.h> | |
19 | #include <linux/types.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/fs.h> | |
22 | #include <linux/miscdevice.h> | |
23 | #include <linux/watchdog.h> | |
24 | #include <linux/init.h> | |
25 | #include <linux/bitops.h> | |
26 | ||
27 | #include <asm/hardware.h> | |
28 | #include <asm/uaccess.h> | |
29 | ||
30 | #ifdef CONFIG_WATCHDOG_NOWAYOUT | |
31 | static int nowayout = 1; | |
32 | #else | |
33 | static int nowayout = 0; | |
34 | #endif | |
35 | static int heartbeat = 60; /* (secs) Default is 1 minute */ | |
36 | static unsigned long wdt_status; | |
37 | static unsigned long boot_status; | |
38 | ||
39 | #define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL) | |
40 | ||
41 | #define WDT_IN_USE 0 | |
42 | #define WDT_OK_TO_CLOSE 1 | |
43 | ||
44 | static void | |
45 | wdt_enable(void) | |
46 | { | |
47 | *IXP4XX_OSWK = IXP4XX_WDT_KEY; | |
48 | *IXP4XX_OSWE = 0; | |
49 | *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat; | |
50 | *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE; | |
51 | *IXP4XX_OSWK = 0; | |
52 | } | |
53 | ||
54 | static void | |
55 | wdt_disable(void) | |
56 | { | |
57 | *IXP4XX_OSWK = IXP4XX_WDT_KEY; | |
58 | *IXP4XX_OSWE = 0; | |
59 | *IXP4XX_OSWK = 0; | |
60 | } | |
61 | ||
62 | static int | |
63 | ixp4xx_wdt_open(struct inode *inode, struct file *file) | |
64 | { | |
65 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) | |
66 | return -EBUSY; | |
67 | ||
68 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
69 | ||
70 | wdt_enable(); | |
71 | ||
72 | return nonseekable_open(inode, file); | |
73 | } | |
74 | ||
75 | static ssize_t | |
76 | ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) | |
77 | { | |
78 | if (len) { | |
79 | if (!nowayout) { | |
80 | size_t i; | |
81 | ||
82 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
83 | ||
84 | for (i = 0; i != len; i++) { | |
85 | char c; | |
86 | ||
87 | if (get_user(c, data + i)) | |
88 | return -EFAULT; | |
89 | if (c == 'V') | |
90 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
91 | } | |
92 | } | |
93 | wdt_enable(); | |
94 | } | |
95 | ||
96 | return len; | |
97 | } | |
98 | ||
99 | static struct watchdog_info ident = { | |
100 | .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | | |
101 | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
102 | .identity = "IXP4xx Watchdog", | |
103 | }; | |
104 | ||
105 | ||
106 | static int | |
107 | ixp4xx_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
108 | unsigned long arg) | |
109 | { | |
110 | int ret = -ENOIOCTLCMD; | |
111 | int time; | |
112 | ||
113 | switch (cmd) { | |
114 | case WDIOC_GETSUPPORT: | |
115 | ret = copy_to_user((struct watchdog_info *)arg, &ident, | |
116 | sizeof(ident)) ? -EFAULT : 0; | |
117 | break; | |
118 | ||
119 | case WDIOC_GETSTATUS: | |
120 | ret = put_user(0, (int *)arg); | |
121 | break; | |
122 | ||
123 | case WDIOC_GETBOOTSTATUS: | |
124 | ret = put_user(boot_status, (int *)arg); | |
125 | break; | |
126 | ||
127 | case WDIOC_SETTIMEOUT: | |
128 | ret = get_user(time, (int *)arg); | |
129 | if (ret) | |
130 | break; | |
131 | ||
132 | if (time <= 0 || time > 60) { | |
133 | ret = -EINVAL; | |
134 | break; | |
135 | } | |
136 | ||
137 | heartbeat = time; | |
138 | wdt_enable(); | |
139 | /* Fall through */ | |
140 | ||
141 | case WDIOC_GETTIMEOUT: | |
142 | ret = put_user(heartbeat, (int *)arg); | |
143 | break; | |
144 | ||
145 | case WDIOC_KEEPALIVE: | |
146 | wdt_enable(); | |
147 | ret = 0; | |
148 | break; | |
149 | } | |
150 | return ret; | |
151 | } | |
152 | ||
153 | static int | |
154 | ixp4xx_wdt_release(struct inode *inode, struct file *file) | |
155 | { | |
156 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { | |
157 | wdt_disable(); | |
158 | } else { | |
159 | printk(KERN_CRIT "WATCHDOG: Device closed unexpectdly - " | |
160 | "timer will not stop\n"); | |
161 | } | |
162 | ||
163 | clear_bit(WDT_IN_USE, &wdt_status); | |
164 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
165 | ||
166 | return 0; | |
167 | } | |
168 | ||
169 | ||
170 | static struct file_operations ixp4xx_wdt_fops = | |
171 | { | |
172 | .owner = THIS_MODULE, | |
173 | .llseek = no_llseek, | |
174 | .write = ixp4xx_wdt_write, | |
175 | .ioctl = ixp4xx_wdt_ioctl, | |
176 | .open = ixp4xx_wdt_open, | |
177 | .release = ixp4xx_wdt_release, | |
178 | }; | |
179 | ||
180 | static struct miscdevice ixp4xx_wdt_miscdev = | |
181 | { | |
182 | .minor = WATCHDOG_MINOR, | |
183 | .name = "IXP4xx Watchdog", | |
184 | .fops = &ixp4xx_wdt_fops, | |
185 | }; | |
186 | ||
187 | static int __init ixp4xx_wdt_init(void) | |
188 | { | |
189 | int ret; | |
190 | unsigned long processor_id; | |
191 | ||
192 | asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :); | |
193 | if (!(processor_id & 0xf)) { | |
194 | printk("IXP4XXX Watchdog: Rev. A0 CPU detected - " | |
195 | "watchdog disabled\n"); | |
196 | ||
197 | return -ENODEV; | |
198 | } | |
199 | ||
200 | ret = misc_register(&ixp4xx_wdt_miscdev); | |
201 | if (ret == 0) | |
202 | printk("IXP4xx Watchdog Timer: heartbeat %d sec\n", heartbeat); | |
203 | ||
204 | boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ? | |
205 | WDIOF_CARDRESET : 0; | |
206 | ||
207 | return ret; | |
208 | } | |
209 | ||
210 | static void __exit ixp4xx_wdt_exit(void) | |
211 | { | |
212 | misc_deregister(&ixp4xx_wdt_miscdev); | |
213 | } | |
214 | ||
215 | ||
216 | module_init(ixp4xx_wdt_init); | |
217 | module_exit(ixp4xx_wdt_exit); | |
218 | ||
219 | MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); | |
220 | MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog"); | |
221 | ||
222 | module_param(heartbeat, int, 0); | |
223 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)"); | |
224 | ||
225 | module_param(nowayout, int, 0); | |
226 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); | |
227 | ||
228 | MODULE_LICENSE("GPL"); | |
229 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
230 |