1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Driver for the MTX-1 Watchdog.
4 *
5 * (C) Copyright 2005 4G Systems <info@4g-systems.biz>,
6 * All Rights Reserved.
7 * http://www.4g-systems.biz
8 *
9 * (C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org>
10 * (c) Copyright 2005 4G Systems <info@4g-systems.biz>
11 *
12 * Release 0.01.
13 * Author: Michael Stickel michael.stickel@4g-systems.biz
14 *
15 * Release 0.02.
16 * Author: Florian Fainelli florian@openwrt.org
17 * use the Linux watchdog/timer APIs
18 *
19 * The Watchdog is configured to reset the MTX-1
20 * if it is not triggered for 100 seconds.
21 * It should not be triggered more often than 1.6 seconds.
22 *
23 * A timer triggers the watchdog every 5 seconds, until
24 * it is opened for the first time. After the first open
25 * it MUST be triggered every 2..95 seconds.
26 */
27
28 #include <linux/module.h>
29 #include <linux/moduleparam.h>
30 #include <linux/types.h>
31 #include <linux/errno.h>
32 #include <linux/miscdevice.h>
33 #include <linux/fs.h>
34 #include <linux/ioport.h>
35 #include <linux/timer.h>
36 #include <linux/completion.h>
37 #include <linux/jiffies.h>
38 #include <linux/watchdog.h>
39 #include <linux/platform_device.h>
40 #include <linux/io.h>
41 #include <linux/uaccess.h>
42 #include <linux/gpio/consumer.h>
43
44 #include <asm/mach-au1x00/au1000.h>
45
46 #define MTX1_WDT_INTERVAL (5 * HZ)
47
48 static int ticks = 100 * HZ;
49
50 static struct {
51 struct completion stop;
52 spinlock_t lock;
53 int running;
54 struct timer_list timer;
55 int queue;
56 int default_ticks;
57 unsigned long inuse;
58 struct gpio_desc *gpiod;
59 unsigned int gstate;
60 } mtx1_wdt_device;
61
mtx1_wdt_trigger(struct timer_list * unused)62 static void mtx1_wdt_trigger(struct timer_list *unused)
63 {
64 spin_lock(&mtx1_wdt_device.lock);
65 if (mtx1_wdt_device.running)
66 ticks--;
67
68 /* toggle wdt gpio */
69 mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate;
70 gpiod_set_value(mtx1_wdt_device.gpiod, mtx1_wdt_device.gstate);
71
72 if (mtx1_wdt_device.queue && ticks)
73 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
74 else
75 complete(&mtx1_wdt_device.stop);
76 spin_unlock(&mtx1_wdt_device.lock);
77 }
78
mtx1_wdt_reset(void)79 static void mtx1_wdt_reset(void)
80 {
81 ticks = mtx1_wdt_device.default_ticks;
82 }
83
84
mtx1_wdt_start(void)85 static void mtx1_wdt_start(void)
86 {
87 unsigned long flags;
88
89 spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
90 if (!mtx1_wdt_device.queue) {
91 mtx1_wdt_device.queue = 1;
92 mtx1_wdt_device.gstate = 1;
93 gpiod_set_value(mtx1_wdt_device.gpiod, 1);
94 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
95 }
96 mtx1_wdt_device.running++;
97 spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
98 }
99
mtx1_wdt_stop(void)100 static int mtx1_wdt_stop(void)
101 {
102 unsigned long flags;
103
104 spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
105 if (mtx1_wdt_device.queue) {
106 mtx1_wdt_device.queue = 0;
107 mtx1_wdt_device.gstate = 0;
108 gpiod_set_value(mtx1_wdt_device.gpiod, 0);
109 }
110 ticks = mtx1_wdt_device.default_ticks;
111 spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
112 return 0;
113 }
114
115 /* Filesystem functions */
116
mtx1_wdt_open(struct inode * inode,struct file * file)117 static int mtx1_wdt_open(struct inode *inode, struct file *file)
118 {
119 if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
120 return -EBUSY;
121 return stream_open(inode, file);
122 }
123
124
mtx1_wdt_release(struct inode * inode,struct file * file)125 static int mtx1_wdt_release(struct inode *inode, struct file *file)
126 {
127 clear_bit(0, &mtx1_wdt_device.inuse);
128 return 0;
129 }
130
mtx1_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)131 static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
132 unsigned long arg)
133 {
134 void __user *argp = (void __user *)arg;
135 int __user *p = (int __user *)argp;
136 unsigned int value;
137 static const struct watchdog_info ident = {
138 .options = WDIOF_CARDRESET,
139 .identity = "MTX-1 WDT",
140 };
141
142 switch (cmd) {
143 case WDIOC_GETSUPPORT:
144 if (copy_to_user(argp, &ident, sizeof(ident)))
145 return -EFAULT;
146 break;
147 case WDIOC_GETSTATUS:
148 case WDIOC_GETBOOTSTATUS:
149 put_user(0, p);
150 break;
151 case WDIOC_SETOPTIONS:
152 if (get_user(value, p))
153 return -EFAULT;
154 if (value & WDIOS_ENABLECARD)
155 mtx1_wdt_start();
156 else if (value & WDIOS_DISABLECARD)
157 mtx1_wdt_stop();
158 else
159 return -EINVAL;
160 return 0;
161 case WDIOC_KEEPALIVE:
162 mtx1_wdt_reset();
163 break;
164 default:
165 return -ENOTTY;
166 }
167 return 0;
168 }
169
170
mtx1_wdt_write(struct file * file,const char * buf,size_t count,loff_t * ppos)171 static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
172 size_t count, loff_t *ppos)
173 {
174 if (!count)
175 return -EIO;
176 mtx1_wdt_reset();
177 return count;
178 }
179
180 static const struct file_operations mtx1_wdt_fops = {
181 .owner = THIS_MODULE,
182 .llseek = no_llseek,
183 .unlocked_ioctl = mtx1_wdt_ioctl,
184 .open = mtx1_wdt_open,
185 .write = mtx1_wdt_write,
186 .release = mtx1_wdt_release,
187 };
188
189
190 static struct miscdevice mtx1_wdt_misc = {
191 .minor = WATCHDOG_MINOR,
192 .name = "watchdog",
193 .fops = &mtx1_wdt_fops,
194 };
195
196
mtx1_wdt_probe(struct platform_device * pdev)197 static int mtx1_wdt_probe(struct platform_device *pdev)
198 {
199 int ret;
200
201 mtx1_wdt_device.gpiod = devm_gpiod_get(&pdev->dev,
202 NULL, GPIOD_OUT_HIGH);
203 if (IS_ERR(mtx1_wdt_device.gpiod)) {
204 dev_err(&pdev->dev, "failed to request gpio");
205 return PTR_ERR(mtx1_wdt_device.gpiod);
206 }
207
208 spin_lock_init(&mtx1_wdt_device.lock);
209 init_completion(&mtx1_wdt_device.stop);
210 mtx1_wdt_device.queue = 0;
211 clear_bit(0, &mtx1_wdt_device.inuse);
212 timer_setup(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0);
213 mtx1_wdt_device.default_ticks = ticks;
214
215 ret = misc_register(&mtx1_wdt_misc);
216 if (ret < 0) {
217 dev_err(&pdev->dev, "failed to register\n");
218 return ret;
219 }
220 mtx1_wdt_start();
221 dev_info(&pdev->dev, "MTX-1 Watchdog driver\n");
222 return 0;
223 }
224
mtx1_wdt_remove(struct platform_device * pdev)225 static int mtx1_wdt_remove(struct platform_device *pdev)
226 {
227 /* FIXME: do we need to lock this test ? */
228 if (mtx1_wdt_device.queue) {
229 mtx1_wdt_device.queue = 0;
230 wait_for_completion(&mtx1_wdt_device.stop);
231 }
232
233 misc_deregister(&mtx1_wdt_misc);
234 return 0;
235 }
236
237 static struct platform_driver mtx1_wdt_driver = {
238 .probe = mtx1_wdt_probe,
239 .remove = mtx1_wdt_remove,
240 .driver.name = "mtx1-wdt",
241 .driver.owner = THIS_MODULE,
242 };
243
244 module_platform_driver(mtx1_wdt_driver);
245
246 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
247 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
248 MODULE_LICENSE("GPL");
249 MODULE_ALIAS("platform:mtx1-wdt");
250