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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
eed6565f CC |
2 | /* |
3 | * SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3 | |
4 | * single board computer | |
5 | * | |
6 | * (c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights | |
7 | * Reserved. | |
8 | * | |
29fa0586 | 9 | * based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk> |
eed6565f CC |
10 | */ |
11 | ||
27c766aa JP |
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
13 | ||
eed6565f CC |
14 | #include <linux/module.h> |
15 | #include <linux/moduleparam.h> | |
eed6565f CC |
16 | #include <linux/types.h> |
17 | #include <linux/kernel.h> | |
18 | #include <linux/fs.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/miscdevice.h> | |
21 | #include <linux/watchdog.h> | |
22 | #include <linux/notifier.h> | |
23 | #include <linux/reboot.h> | |
24 | #include <linux/init.h> | |
de6c642c | 25 | #include <linux/ioport.h> |
f4f6f65a AC |
26 | #include <linux/uaccess.h> |
27 | #include <linux/io.h> | |
eed6565f | 28 | |
eed6565f CC |
29 | static int epx_c3_alive; |
30 | ||
31 | #define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */ | |
32 | ||
86a1e189 WVS |
33 | static bool nowayout = WATCHDOG_NOWAYOUT; |
34 | module_param(nowayout, bool, 0); | |
143a2e54 WVS |
35 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
36 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
eed6565f CC |
37 | |
38 | #define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */ | |
39 | #define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */ | |
40 | ||
41 | static void epx_c3_start(void) | |
42 | { | |
43 | outb(1, EPXC3_WATCHDOG_CTL_REG); | |
44 | } | |
45 | ||
46 | static void epx_c3_stop(void) | |
47 | { | |
48 | ||
49 | outb(0, EPXC3_WATCHDOG_CTL_REG); | |
50 | ||
27c766aa | 51 | pr_info("Stopped watchdog timer\n"); |
eed6565f CC |
52 | } |
53 | ||
54 | static void epx_c3_pet(void) | |
55 | { | |
56 | outb(1, EPXC3_WATCHDOG_PET_REG); | |
57 | } | |
58 | ||
59 | /* | |
60 | * Allow only one person to hold it open | |
61 | */ | |
62 | static int epx_c3_open(struct inode *inode, struct file *file) | |
63 | { | |
64 | if (epx_c3_alive) | |
65 | return -EBUSY; | |
66 | ||
67 | if (nowayout) | |
68 | __module_get(THIS_MODULE); | |
69 | ||
70 | /* Activate timer */ | |
71 | epx_c3_start(); | |
72 | epx_c3_pet(); | |
73 | ||
74 | epx_c3_alive = 1; | |
27c766aa | 75 | pr_info("Started watchdog timer\n"); |
eed6565f | 76 | |
c5bf68fe | 77 | return stream_open(inode, file); |
eed6565f CC |
78 | } |
79 | ||
80 | static int epx_c3_release(struct inode *inode, struct file *file) | |
81 | { | |
82 | /* Shut off the timer. | |
83 | * Lock it in if it's a module and we defined ...NOWAYOUT */ | |
84 | if (!nowayout) | |
85 | epx_c3_stop(); /* Turn the WDT off */ | |
86 | ||
87 | epx_c3_alive = 0; | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
73a09e62 | 92 | static ssize_t epx_c3_write(struct file *file, const char __user *data, |
eed6565f CC |
93 | size_t len, loff_t *ppos) |
94 | { | |
95 | /* Refresh the timer. */ | |
96 | if (len) | |
97 | epx_c3_pet(); | |
98 | return len; | |
99 | } | |
100 | ||
f4f6f65a AC |
101 | static long epx_c3_ioctl(struct file *file, unsigned int cmd, |
102 | unsigned long arg) | |
eed6565f CC |
103 | { |
104 | int options, retval = -EINVAL; | |
73a09e62 | 105 | int __user *argp = (void __user *)arg; |
f4f6f65a | 106 | static const struct watchdog_info ident = { |
e73a7802 | 107 | .options = WDIOF_KEEPALIVEPING, |
eed6565f CC |
108 | .firmware_version = 0, |
109 | .identity = "Winsystems EPX-C3 H/W Watchdog", | |
110 | }; | |
111 | ||
112 | switch (cmd) { | |
113 | case WDIOC_GETSUPPORT: | |
73a09e62 | 114 | if (copy_to_user(argp, &ident, sizeof(ident))) |
eed6565f CC |
115 | return -EFAULT; |
116 | return 0; | |
117 | case WDIOC_GETSTATUS: | |
118 | case WDIOC_GETBOOTSTATUS: | |
73a09e62 | 119 | return put_user(0, argp); |
73a09e62 AV |
120 | case WDIOC_SETOPTIONS: |
121 | if (get_user(options, argp)) | |
eed6565f CC |
122 | return -EFAULT; |
123 | ||
124 | if (options & WDIOS_DISABLECARD) { | |
125 | epx_c3_stop(); | |
126 | retval = 0; | |
127 | } | |
128 | ||
129 | if (options & WDIOS_ENABLECARD) { | |
130 | epx_c3_start(); | |
131 | retval = 0; | |
132 | } | |
133 | ||
134 | return retval; | |
0c06090c WVS |
135 | case WDIOC_KEEPALIVE: |
136 | epx_c3_pet(); | |
137 | return 0; | |
138 | case WDIOC_GETTIMEOUT: | |
139 | return put_user(WATCHDOG_TIMEOUT, argp); | |
eed6565f | 140 | default: |
795b89d2 | 141 | return -ENOTTY; |
eed6565f CC |
142 | } |
143 | } | |
144 | ||
145 | static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code, | |
146 | void *unused) | |
147 | { | |
148 | if (code == SYS_DOWN || code == SYS_HALT) | |
149 | epx_c3_stop(); /* Turn the WDT off */ | |
150 | ||
151 | return NOTIFY_DONE; | |
152 | } | |
153 | ||
62322d25 | 154 | static const struct file_operations epx_c3_fops = { |
eed6565f CC |
155 | .owner = THIS_MODULE, |
156 | .llseek = no_llseek, | |
157 | .write = epx_c3_write, | |
f4f6f65a | 158 | .unlocked_ioctl = epx_c3_ioctl, |
b6dfb247 | 159 | .compat_ioctl = compat_ptr_ioctl, |
eed6565f CC |
160 | .open = epx_c3_open, |
161 | .release = epx_c3_release, | |
162 | }; | |
163 | ||
164 | static struct miscdevice epx_c3_miscdev = { | |
165 | .minor = WATCHDOG_MINOR, | |
166 | .name = "watchdog", | |
167 | .fops = &epx_c3_fops, | |
168 | }; | |
169 | ||
170 | static struct notifier_block epx_c3_notifier = { | |
171 | .notifier_call = epx_c3_notify_sys, | |
172 | }; | |
173 | ||
eed6565f CC |
174 | static int __init watchdog_init(void) |
175 | { | |
176 | int ret; | |
177 | ||
de6c642c AC |
178 | if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog")) |
179 | return -EBUSY; | |
180 | ||
eed6565f CC |
181 | ret = register_reboot_notifier(&epx_c3_notifier); |
182 | if (ret) { | |
27c766aa | 183 | pr_err("cannot register reboot notifier (err=%d)\n", ret); |
de6c642c | 184 | goto out; |
eed6565f CC |
185 | } |
186 | ||
187 | ret = misc_register(&epx_c3_miscdev); | |
188 | if (ret) { | |
27c766aa JP |
189 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
190 | WATCHDOG_MINOR, ret); | |
eed6565f | 191 | unregister_reboot_notifier(&epx_c3_notifier); |
de6c642c | 192 | goto out; |
eed6565f CC |
193 | } |
194 | ||
27c766aa | 195 | pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n"); |
eed6565f CC |
196 | |
197 | return 0; | |
de6c642c AC |
198 | |
199 | out: | |
200 | release_region(EPXC3_WATCHDOG_CTL_REG, 2); | |
201 | return ret; | |
eed6565f CC |
202 | } |
203 | ||
204 | static void __exit watchdog_exit(void) | |
205 | { | |
206 | misc_deregister(&epx_c3_miscdev); | |
207 | unregister_reboot_notifier(&epx_c3_notifier); | |
de6c642c | 208 | release_region(EPXC3_WATCHDOG_CTL_REG, 2); |
eed6565f CC |
209 | } |
210 | ||
211 | module_init(watchdog_init); | |
212 | module_exit(watchdog_exit); | |
213 | ||
214 | MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>"); | |
a77dba7e WVS |
215 | MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. " |
216 | "Note that there is no way to probe for this device -- " | |
ae0e47f0 | 217 | "so only use it if you are *sure* you are running on this specific " |
a77dba7e | 218 | "SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!"); |
eed6565f | 219 | MODULE_LICENSE("GPL"); |