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1 | /* |
2 | * drivers/char/watchdog/ixp2000_wdt.c |
3 | * |
4 | * Watchdog driver for Intel IXP2000 network processors |
5 | * |
6 | * Adapted from the IXP4xx watchdog driver by Lennert Buytenhek. |
7 | * The original version carries these notices: |
8 | * |
9 | * Author: Deepak Saxena <dsaxena@plexity.net> |
10 | * |
11 | * Copyright 2004 (c) MontaVista, Software, Inc. |
12 | * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> |
13 | * |
14 | * This file is licensed under the terms of the GNU General Public |
15 | * License version 2. This program is licensed "as is" without any |
16 | * warranty of any kind, whether express or implied. |
17 | */ |
18 | |
19 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
20 | |
21 | #include <linux/module.h> |
22 | #include <linux/moduleparam.h> |
23 | #include <linux/types.h> |
24 | #include <linux/timer.h> |
25 | #include <linux/kernel.h> |
26 | #include <linux/fs.h> |
27 | #include <linux/miscdevice.h> |
28 | #include <linux/watchdog.h> |
29 | #include <linux/init.h> |
30 | #include <linux/bitops.h> |
31 | #include <linux/uaccess.h> |
32 | #include <mach/hardware.h> |
33 | |
34 | static bool nowayout = WATCHDOG_NOWAYOUT; |
35 | static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */ |
36 | static unsigned long wdt_status; |
37 | static DEFINE_SPINLOCK(wdt_lock); |
38 | |
39 | #define WDT_IN_USE 0 |
40 | #define WDT_OK_TO_CLOSE 1 |
41 | |
42 | static unsigned long wdt_tick_rate; |
43 | |
44 | static void wdt_enable(void) |
45 | { |
46 | spin_lock(&wdt_lock); |
47 | ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE); |
48 | ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE); |
49 | ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate); |
50 | ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE); |
51 | spin_unlock(&wdt_lock); |
52 | } |
53 | |
54 | static void wdt_disable(void) |
55 | { |
56 | spin_lock(&wdt_lock); |
57 | ixp2000_reg_write(IXP2000_T4_CTL, 0); |
58 | spin_unlock(&wdt_lock); |
59 | } |
60 | |
61 | static void wdt_keepalive(void) |
62 | { |
63 | spin_lock(&wdt_lock); |
64 | ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate); |
65 | spin_unlock(&wdt_lock); |
66 | } |
67 | |
68 | static int ixp2000_wdt_open(struct inode *inode, struct file *file) |
69 | { |
70 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
71 | return -EBUSY; |
72 | |
73 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
74 | |
75 | wdt_enable(); |
76 | |
77 | return nonseekable_open(inode, file); |
78 | } |
79 | |
80 | static ssize_t ixp2000_wdt_write(struct file *file, const char *data, |
81 | size_t len, loff_t *ppos) |
82 | { |
83 | if (len) { |
84 | if (!nowayout) { |
85 | size_t i; |
86 | |
87 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
88 | |
89 | for (i = 0; i != len; i++) { |
90 | char c; |
91 | |
92 | if (get_user(c, data + i)) |
93 | return -EFAULT; |
94 | if (c == 'V') |
95 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
96 | } |
97 | } |
98 | wdt_keepalive(); |
99 | } |
100 | |
101 | return len; |
102 | } |
103 | |
104 | |
105 | static const struct watchdog_info ident = { |
106 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | |
107 | WDIOF_KEEPALIVEPING, |
108 | .identity = "IXP2000 Watchdog", |
109 | }; |
110 | |
111 | static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd, |
112 | unsigned long arg) |
113 | { |
114 | int ret = -ENOTTY; |
115 | int time; |
116 | |
117 | switch (cmd) { |
118 | case WDIOC_GETSUPPORT: |
119 | ret = copy_to_user((struct watchdog_info *)arg, &ident, |
120 | sizeof(ident)) ? -EFAULT : 0; |
121 | break; |
122 | |
123 | case WDIOC_GETSTATUS: |
124 | ret = put_user(0, (int *)arg); |
125 | break; |
126 | |
127 | case WDIOC_GETBOOTSTATUS: |
128 | ret = put_user(0, (int *)arg); |
129 | break; |
130 | |
131 | case WDIOC_KEEPALIVE: |
132 | wdt_enable(); |
133 | ret = 0; |
134 | break; |
135 | |
136 | case WDIOC_SETTIMEOUT: |
137 | ret = get_user(time, (int *)arg); |
138 | if (ret) |
139 | break; |
140 | |
141 | if (time <= 0 || time > 60) { |
142 | ret = -EINVAL; |
143 | break; |
144 | } |
145 | |
146 | heartbeat = time; |
147 | wdt_keepalive(); |
148 | /* Fall through */ |
149 | |
150 | case WDIOC_GETTIMEOUT: |
151 | ret = put_user(heartbeat, (int *)arg); |
152 | break; |
153 | } |
154 | |
155 | return ret; |
156 | } |
157 | |
158 | static int ixp2000_wdt_release(struct inode *inode, struct file *file) |
159 | { |
160 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) |
161 | wdt_disable(); |
162 | else |
163 | pr_crit("Device closed unexpectedly - timer will not stop\n"); |
164 | clear_bit(WDT_IN_USE, &wdt_status); |
165 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
166 | |
167 | return 0; |
168 | } |
169 | |
170 | |
171 | static const struct file_operations ixp2000_wdt_fops = { |
172 | .owner = THIS_MODULE, |
173 | .llseek = no_llseek, |
174 | .write = ixp2000_wdt_write, |
175 | .unlocked_ioctl = ixp2000_wdt_ioctl, |
176 | .open = ixp2000_wdt_open, |
177 | .release = ixp2000_wdt_release, |
178 | }; |
179 | |
180 | static struct miscdevice ixp2000_wdt_miscdev = { |
181 | .minor = WATCHDOG_MINOR, |
182 | .name = "watchdog", |
183 | .fops = &ixp2000_wdt_fops, |
184 | }; |
185 | |
186 | static int __init ixp2000_wdt_init(void) |
187 | { |
188 | if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) { |
189 | pr_info("Unable to use IXP2000 watchdog due to IXP2800 erratum #25\n"); |
190 | return -EIO; |
191 | } |
192 | wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256; |
193 | return misc_register(&ixp2000_wdt_miscdev); |
194 | } |
195 | |
196 | static void __exit ixp2000_wdt_exit(void) |
197 | { |
198 | misc_deregister(&ixp2000_wdt_miscdev); |
199 | } |
200 | |
201 | module_init(ixp2000_wdt_init); |
202 | module_exit(ixp2000_wdt_exit); |
203 | |
204 | MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); |
205 | MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog"); |
206 | |
207 | module_param(heartbeat, int, 0); |
208 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)"); |
209 | |
210 | module_param(nowayout, bool, 0); |
211 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
212 | |
213 | MODULE_LICENSE("GPL"); |
214 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
215 | |
216 |
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