1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Watchdog driver for SBC-FITPC2 board |
4 | * |
5 | * Author: Denis Turischev <denis@compulab.co.il> |
6 | * |
7 | * Adapted from the IXP2000 watchdog driver by Deepak Saxena. |
8 | * |
9 | */ |
10 | |
11 | #define pr_fmt(fmt) KBUILD_MODNAME " WATCHDOG: " fmt |
12 | |
13 | #include <linux/module.h> |
14 | #include <linux/types.h> |
15 | #include <linux/miscdevice.h> |
16 | #include <linux/watchdog.h> |
17 | #include <linux/ioport.h> |
18 | #include <linux/delay.h> |
19 | #include <linux/fs.h> |
20 | #include <linux/init.h> |
21 | #include <linux/moduleparam.h> |
22 | #include <linux/dmi.h> |
23 | #include <linux/io.h> |
24 | #include <linux/uaccess.h> |
25 | |
26 | |
27 | static bool nowayout = WATCHDOG_NOWAYOUT; |
28 | static unsigned int margin = 60; /* (secs) Default is 1 minute */ |
29 | static unsigned long wdt_status; |
30 | static DEFINE_MUTEX(wdt_lock); |
31 | |
32 | #define WDT_IN_USE 0 |
33 | #define WDT_OK_TO_CLOSE 1 |
34 | |
35 | #define COMMAND_PORT 0x4c |
36 | #define DATA_PORT 0x48 |
37 | |
38 | #define IFACE_ON_COMMAND 1 |
39 | #define REBOOT_COMMAND 2 |
40 | |
41 | #define WATCHDOG_NAME "SBC-FITPC2 Watchdog" |
42 | |
43 | static void wdt_send_data(unsigned char command, unsigned char data) |
44 | { |
45 | outb(value: data, DATA_PORT); |
46 | msleep(msecs: 200); |
47 | outb(value: command, COMMAND_PORT); |
48 | msleep(msecs: 100); |
49 | } |
50 | |
51 | static void wdt_enable(void) |
52 | { |
53 | mutex_lock(&wdt_lock); |
54 | wdt_send_data(IFACE_ON_COMMAND, data: 1); |
55 | wdt_send_data(REBOOT_COMMAND, data: margin); |
56 | mutex_unlock(lock: &wdt_lock); |
57 | } |
58 | |
59 | static void wdt_disable(void) |
60 | { |
61 | mutex_lock(&wdt_lock); |
62 | wdt_send_data(IFACE_ON_COMMAND, data: 0); |
63 | wdt_send_data(REBOOT_COMMAND, data: 0); |
64 | mutex_unlock(lock: &wdt_lock); |
65 | } |
66 | |
67 | static int fitpc2_wdt_open(struct inode *inode, struct file *file) |
68 | { |
69 | if (test_and_set_bit(WDT_IN_USE, addr: &wdt_status)) |
70 | return -EBUSY; |
71 | |
72 | clear_bit(WDT_OK_TO_CLOSE, addr: &wdt_status); |
73 | |
74 | wdt_enable(); |
75 | |
76 | return stream_open(inode, filp: file); |
77 | } |
78 | |
79 | static ssize_t fitpc2_wdt_write(struct file *file, const char __user *data, |
80 | size_t len, loff_t *ppos) |
81 | { |
82 | size_t i; |
83 | |
84 | if (!len) |
85 | return 0; |
86 | |
87 | if (nowayout) { |
88 | len = 0; |
89 | goto out; |
90 | } |
91 | |
92 | clear_bit(WDT_OK_TO_CLOSE, addr: &wdt_status); |
93 | |
94 | for (i = 0; i != len; i++) { |
95 | char c; |
96 | |
97 | if (get_user(c, data + i)) |
98 | return -EFAULT; |
99 | |
100 | if (c == 'V') |
101 | set_bit(WDT_OK_TO_CLOSE, addr: &wdt_status); |
102 | } |
103 | |
104 | out: |
105 | wdt_enable(); |
106 | |
107 | return len; |
108 | } |
109 | |
110 | |
111 | static const struct watchdog_info ident = { |
112 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | |
113 | WDIOF_KEEPALIVEPING, |
114 | .identity = WATCHDOG_NAME, |
115 | }; |
116 | |
117 | |
118 | static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd, |
119 | unsigned long arg) |
120 | { |
121 | int ret = -ENOTTY; |
122 | int time; |
123 | |
124 | switch (cmd) { |
125 | case WDIOC_GETSUPPORT: |
126 | ret = copy_to_user(to: (struct watchdog_info __user *)arg, from: &ident, |
127 | n: sizeof(ident)) ? -EFAULT : 0; |
128 | break; |
129 | |
130 | case WDIOC_GETSTATUS: |
131 | ret = put_user(0, (int __user *)arg); |
132 | break; |
133 | |
134 | case WDIOC_GETBOOTSTATUS: |
135 | ret = put_user(0, (int __user *)arg); |
136 | break; |
137 | |
138 | case WDIOC_KEEPALIVE: |
139 | wdt_enable(); |
140 | ret = 0; |
141 | break; |
142 | |
143 | case WDIOC_SETTIMEOUT: |
144 | ret = get_user(time, (int __user *)arg); |
145 | if (ret) |
146 | break; |
147 | |
148 | if (time < 31 || time > 255) { |
149 | ret = -EINVAL; |
150 | break; |
151 | } |
152 | |
153 | margin = time; |
154 | wdt_enable(); |
155 | fallthrough; |
156 | |
157 | case WDIOC_GETTIMEOUT: |
158 | ret = put_user(margin, (int __user *)arg); |
159 | break; |
160 | } |
161 | |
162 | return ret; |
163 | } |
164 | |
165 | static int fitpc2_wdt_release(struct inode *inode, struct file *file) |
166 | { |
167 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { |
168 | wdt_disable(); |
169 | pr_info("Device disabled\n" ); |
170 | } else { |
171 | pr_warn("Device closed unexpectedly - timer will not stop\n" ); |
172 | wdt_enable(); |
173 | } |
174 | |
175 | clear_bit(WDT_IN_USE, addr: &wdt_status); |
176 | clear_bit(WDT_OK_TO_CLOSE, addr: &wdt_status); |
177 | |
178 | return 0; |
179 | } |
180 | |
181 | |
182 | static const struct file_operations fitpc2_wdt_fops = { |
183 | .owner = THIS_MODULE, |
184 | .llseek = no_llseek, |
185 | .write = fitpc2_wdt_write, |
186 | .unlocked_ioctl = fitpc2_wdt_ioctl, |
187 | .compat_ioctl = compat_ptr_ioctl, |
188 | .open = fitpc2_wdt_open, |
189 | .release = fitpc2_wdt_release, |
190 | }; |
191 | |
192 | static struct miscdevice fitpc2_wdt_miscdev = { |
193 | .minor = WATCHDOG_MINOR, |
194 | .name = "watchdog" , |
195 | .fops = &fitpc2_wdt_fops, |
196 | }; |
197 | |
198 | static int __init fitpc2_wdt_init(void) |
199 | { |
200 | int err; |
201 | const char *brd_name; |
202 | |
203 | brd_name = dmi_get_system_info(field: DMI_BOARD_NAME); |
204 | |
205 | if (!brd_name || !strstr(brd_name, "SBC-FITPC2" )) |
206 | return -ENODEV; |
207 | |
208 | pr_info("%s found\n" , brd_name); |
209 | |
210 | if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) { |
211 | pr_err("I/O address 0x%04x already in use\n" , COMMAND_PORT); |
212 | return -EIO; |
213 | } |
214 | |
215 | if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) { |
216 | pr_err("I/O address 0x%04x already in use\n" , DATA_PORT); |
217 | err = -EIO; |
218 | goto err_data_port; |
219 | } |
220 | |
221 | if (margin < 31 || margin > 255) { |
222 | pr_err("margin must be in range 31 - 255 seconds, you tried to set %d\n" , |
223 | margin); |
224 | err = -EINVAL; |
225 | goto err_margin; |
226 | } |
227 | |
228 | err = misc_register(misc: &fitpc2_wdt_miscdev); |
229 | if (err) { |
230 | pr_err("cannot register miscdev on minor=%d (err=%d)\n" , |
231 | WATCHDOG_MINOR, err); |
232 | goto err_margin; |
233 | } |
234 | |
235 | return 0; |
236 | |
237 | err_margin: |
238 | release_region(DATA_PORT, 1); |
239 | err_data_port: |
240 | release_region(COMMAND_PORT, 1); |
241 | |
242 | return err; |
243 | } |
244 | |
245 | static void __exit fitpc2_wdt_exit(void) |
246 | { |
247 | misc_deregister(misc: &fitpc2_wdt_miscdev); |
248 | release_region(DATA_PORT, 1); |
249 | release_region(COMMAND_PORT, 1); |
250 | } |
251 | |
252 | module_init(fitpc2_wdt_init); |
253 | module_exit(fitpc2_wdt_exit); |
254 | |
255 | MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>" ); |
256 | MODULE_DESCRIPTION("SBC-FITPC2 Watchdog" ); |
257 | |
258 | module_param(margin, int, 0); |
259 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)" ); |
260 | |
261 | module_param(nowayout, bool, 0); |
262 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started" ); |
263 | |
264 | MODULE_LICENSE("GPL" ); |
265 | |