1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * sma cpu5 watchdog driver
4 *
5 * Copyright (C) 2003 Heiko Ronsdorf <hero@ihg.uni-duisburg.de>
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/module.h>
11 #include <linux/moduleparam.h>
12 #include <linux/types.h>
13 #include <linux/errno.h>
14 #include <linux/miscdevice.h>
15 #include <linux/fs.h>
16 #include <linux/ioport.h>
17 #include <linux/timer.h>
18 #include <linux/completion.h>
19 #include <linux/jiffies.h>
20 #include <linux/io.h>
21 #include <linux/uaccess.h>
22 #include <linux/watchdog.h>
23
24 /* adjustable parameters */
25
26 static int verbose;
27 static int port = 0x91;
28 static int ticks = 10000;
29 static DEFINE_SPINLOCK(cpu5wdt_lock);
30
31 #define PFX "cpu5wdt: "
32
33 #define CPU5WDT_EXTENT 0x0A
34
35 #define CPU5WDT_STATUS_REG 0x00
36 #define CPU5WDT_TIME_A_REG 0x02
37 #define CPU5WDT_TIME_B_REG 0x03
38 #define CPU5WDT_MODE_REG 0x04
39 #define CPU5WDT_TRIGGER_REG 0x07
40 #define CPU5WDT_ENABLE_REG 0x08
41 #define CPU5WDT_RESET_REG 0x09
42
43 #define CPU5WDT_INTERVAL (HZ/10+1)
44
45 /* some device data */
46
47 static struct {
48 struct completion stop;
49 int running;
50 struct timer_list timer;
51 int queue;
52 int default_ticks;
53 unsigned long inuse;
54 } cpu5wdt_device;
55
56 /* generic helper functions */
57
cpu5wdt_trigger(struct timer_list * unused)58 static void cpu5wdt_trigger(struct timer_list *unused)
59 {
60 if (verbose > 2)
61 pr_debug("trigger at %i ticks\n", ticks);
62
63 if (cpu5wdt_device.running)
64 ticks--;
65
66 spin_lock(&cpu5wdt_lock);
67 /* keep watchdog alive */
68 outb(1, port + CPU5WDT_TRIGGER_REG);
69
70 /* requeue?? */
71 if (cpu5wdt_device.queue && ticks)
72 mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
73 else {
74 /* ticks doesn't matter anyway */
75 complete(&cpu5wdt_device.stop);
76 }
77 spin_unlock(&cpu5wdt_lock);
78
79 }
80
cpu5wdt_reset(void)81 static void cpu5wdt_reset(void)
82 {
83 ticks = cpu5wdt_device.default_ticks;
84
85 if (verbose)
86 pr_debug("reset (%i ticks)\n", (int) ticks);
87
88 }
89
cpu5wdt_start(void)90 static void cpu5wdt_start(void)
91 {
92 unsigned long flags;
93
94 spin_lock_irqsave(&cpu5wdt_lock, flags);
95 if (!cpu5wdt_device.queue) {
96 cpu5wdt_device.queue = 1;
97 outb(0, port + CPU5WDT_TIME_A_REG);
98 outb(0, port + CPU5WDT_TIME_B_REG);
99 outb(1, port + CPU5WDT_MODE_REG);
100 outb(0, port + CPU5WDT_RESET_REG);
101 outb(0, port + CPU5WDT_ENABLE_REG);
102 mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
103 }
104 /* if process dies, counter is not decremented */
105 cpu5wdt_device.running++;
106 spin_unlock_irqrestore(&cpu5wdt_lock, flags);
107 }
108
cpu5wdt_stop(void)109 static int cpu5wdt_stop(void)
110 {
111 unsigned long flags;
112
113 spin_lock_irqsave(&cpu5wdt_lock, flags);
114 if (cpu5wdt_device.running)
115 cpu5wdt_device.running = 0;
116 ticks = cpu5wdt_device.default_ticks;
117 spin_unlock_irqrestore(&cpu5wdt_lock, flags);
118 if (verbose)
119 pr_crit("stop not possible\n");
120 return -EIO;
121 }
122
123 /* filesystem operations */
124
cpu5wdt_open(struct inode * inode,struct file * file)125 static int cpu5wdt_open(struct inode *inode, struct file *file)
126 {
127 if (test_and_set_bit(0, &cpu5wdt_device.inuse))
128 return -EBUSY;
129 return stream_open(inode, file);
130 }
131
cpu5wdt_release(struct inode * inode,struct file * file)132 static int cpu5wdt_release(struct inode *inode, struct file *file)
133 {
134 clear_bit(0, &cpu5wdt_device.inuse);
135 return 0;
136 }
137
cpu5wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)138 static long cpu5wdt_ioctl(struct file *file, unsigned int cmd,
139 unsigned long arg)
140 {
141 void __user *argp = (void __user *)arg;
142 int __user *p = argp;
143 unsigned int value;
144 static const struct watchdog_info ident = {
145 .options = WDIOF_CARDRESET,
146 .identity = "CPU5 WDT",
147 };
148
149 switch (cmd) {
150 case WDIOC_GETSUPPORT:
151 if (copy_to_user(argp, &ident, sizeof(ident)))
152 return -EFAULT;
153 break;
154 case WDIOC_GETSTATUS:
155 value = inb(port + CPU5WDT_STATUS_REG);
156 value = (value >> 2) & 1;
157 return put_user(value, p);
158 case WDIOC_GETBOOTSTATUS:
159 return put_user(0, p);
160 case WDIOC_SETOPTIONS:
161 if (get_user(value, p))
162 return -EFAULT;
163 if (value & WDIOS_ENABLECARD)
164 cpu5wdt_start();
165 if (value & WDIOS_DISABLECARD)
166 cpu5wdt_stop();
167 break;
168 case WDIOC_KEEPALIVE:
169 cpu5wdt_reset();
170 break;
171 default:
172 return -ENOTTY;
173 }
174 return 0;
175 }
176
cpu5wdt_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)177 static ssize_t cpu5wdt_write(struct file *file, const char __user *buf,
178 size_t count, loff_t *ppos)
179 {
180 if (!count)
181 return -EIO;
182 cpu5wdt_reset();
183 return count;
184 }
185
186 static const struct file_operations cpu5wdt_fops = {
187 .owner = THIS_MODULE,
188 .llseek = no_llseek,
189 .unlocked_ioctl = cpu5wdt_ioctl,
190 .compat_ioctl = compat_ptr_ioctl,
191 .open = cpu5wdt_open,
192 .write = cpu5wdt_write,
193 .release = cpu5wdt_release,
194 };
195
196 static struct miscdevice cpu5wdt_misc = {
197 .minor = WATCHDOG_MINOR,
198 .name = "watchdog",
199 .fops = &cpu5wdt_fops,
200 };
201
202 /* init/exit function */
203
cpu5wdt_init(void)204 static int cpu5wdt_init(void)
205 {
206 unsigned int val;
207 int err;
208
209 if (verbose)
210 pr_debug("port=0x%x, verbose=%i\n", port, verbose);
211
212 init_completion(&cpu5wdt_device.stop);
213 cpu5wdt_device.queue = 0;
214 timer_setup(&cpu5wdt_device.timer, cpu5wdt_trigger, 0);
215 cpu5wdt_device.default_ticks = ticks;
216
217 if (!request_region(port, CPU5WDT_EXTENT, PFX)) {
218 pr_err("request_region failed\n");
219 err = -EBUSY;
220 goto no_port;
221 }
222
223 /* watchdog reboot? */
224 val = inb(port + CPU5WDT_STATUS_REG);
225 val = (val >> 2) & 1;
226 if (!val)
227 pr_info("sorry, was my fault\n");
228
229 err = misc_register(&cpu5wdt_misc);
230 if (err < 0) {
231 pr_err("misc_register failed\n");
232 goto no_misc;
233 }
234
235
236 pr_info("init success\n");
237 return 0;
238
239 no_misc:
240 release_region(port, CPU5WDT_EXTENT);
241 no_port:
242 return err;
243 }
244
cpu5wdt_init_module(void)245 static int cpu5wdt_init_module(void)
246 {
247 return cpu5wdt_init();
248 }
249
cpu5wdt_exit(void)250 static void cpu5wdt_exit(void)
251 {
252 if (cpu5wdt_device.queue) {
253 cpu5wdt_device.queue = 0;
254 wait_for_completion(&cpu5wdt_device.stop);
255 del_timer(&cpu5wdt_device.timer);
256 }
257
258 misc_deregister(&cpu5wdt_misc);
259
260 release_region(port, CPU5WDT_EXTENT);
261
262 }
263
cpu5wdt_exit_module(void)264 static void cpu5wdt_exit_module(void)
265 {
266 cpu5wdt_exit();
267 }
268
269 /* module entry points */
270
271 module_init(cpu5wdt_init_module);
272 module_exit(cpu5wdt_exit_module);
273
274 MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
275 MODULE_DESCRIPTION("sma cpu5 watchdog driver");
276 MODULE_LICENSE("GPL");
277
278 module_param_hw(port, int, ioport, 0);
279 MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
280
281 module_param(verbose, int, 0);
282 MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
283
284 module_param(ticks, int, 0);
285 MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");
286
