1 /*
2 * PNX833x Hardware Watchdog Driver
3 * Copyright 2008 NXP Semiconductors
4 * Daniel Laird <daniel.j.laird@nxp.com>
5 * Andre McCurdy <andre.mccurdy@nxp.com>
6 *
7 * Heavily based upon - IndyDog 0.3
8 * A Hardware Watchdog Device for SGI IP22
9 *
10 * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, All Rights Reserved.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 *
17 * based on softdog.c by Alan Cox <alan@redhat.com>
18 */
19
20 #include <linux/module.h>
21 #include <linux/moduleparam.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/fs.h>
25 #include <linux/mm.h>
26 #include <linux/miscdevice.h>
27 #include <linux/watchdog.h>
28 #include <linux/notifier.h>
29 #include <linux/reboot.h>
30 #include <linux/init.h>
31 #include <asm/mach-pnx833x/pnx833x.h>
32
33 #define PFX "pnx833x: "
34 #define WATCHDOG_TIMEOUT 30 /* 30 sec Maximum timeout */
35 #define WATCHDOG_COUNT_FREQUENCY 68000000U /* Watchdog counts at 68MHZ. */
36 #define PNX_WATCHDOG_TIMEOUT (WATCHDOG_TIMEOUT * WATCHDOG_COUNT_FREQUENCY)
37 #define PNX_TIMEOUT_VALUE 2040000000U
38
39 /** CONFIG block */
40 #define PNX833X_CONFIG (0x07000U)
41 #define PNX833X_CONFIG_CPU_WATCHDOG (0x54)
42 #define PNX833X_CONFIG_CPU_WATCHDOG_COMPARE (0x58)
43 #define PNX833X_CONFIG_CPU_COUNTERS_CONTROL (0x1c)
44
45 /** RESET block */
46 #define PNX833X_RESET (0x08000U)
47 #define PNX833X_RESET_CONFIG (0x08)
48
49 static int pnx833x_wdt_alive;
50
51 /* Set default timeout in MHZ.*/
52 static int pnx833x_wdt_timeout = PNX_WATCHDOG_TIMEOUT;
53 module_param(pnx833x_wdt_timeout, int, 0);
54 MODULE_PARM_DESC(timeout, "Watchdog timeout in Mhz. (68Mhz clock), default="
55 __MODULE_STRING(PNX_TIMEOUT_VALUE) "(30 seconds).");
56
57 static int nowayout = WATCHDOG_NOWAYOUT;
58 module_param(nowayout, int, 0);
59 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
60 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
61
62 #define START_DEFAULT 1
63 static int start_enabled = START_DEFAULT;
64 module_param(start_enabled, int, 0);
65 MODULE_PARM_DESC(start_enabled, "Watchdog is started on module insertion "
66 "(default=" __MODULE_STRING(START_DEFAULT) ")");
67
pnx833x_wdt_start(void)68 static void pnx833x_wdt_start(void)
69 {
70 /* Enable watchdog causing reset. */
71 PNX833X_REG(PNX833X_RESET + PNX833X_RESET_CONFIG) |= 0x1;
72 /* Set timeout.*/
73 PNX833X_REG(PNX833X_CONFIG +
74 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
75 /* Enable watchdog. */
76 PNX833X_REG(PNX833X_CONFIG +
77 PNX833X_CONFIG_CPU_COUNTERS_CONTROL) |= 0x1;
78
79 printk(KERN_INFO PFX "Started watchdog timer.\n");
80 }
81
pnx833x_wdt_stop(void)82 static void pnx833x_wdt_stop(void)
83 {
84 /* Disable watchdog causing reset. */
85 PNX833X_REG(PNX833X_RESET + PNX833X_CONFIG) &= 0xFFFFFFFE;
86 /* Disable watchdog.*/
87 PNX833X_REG(PNX833X_CONFIG +
88 PNX833X_CONFIG_CPU_COUNTERS_CONTROL) &= 0xFFFFFFFE;
89
90 printk(KERN_INFO PFX "Stopped watchdog timer.\n");
91 }
92
pnx833x_wdt_ping(void)93 static void pnx833x_wdt_ping(void)
94 {
95 PNX833X_REG(PNX833X_CONFIG +
96 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
97 }
98
99 /*
100 * Allow only one person to hold it open
101 */
pnx833x_wdt_open(struct inode * inode,struct file * file)102 static int pnx833x_wdt_open(struct inode *inode, struct file *file)
103 {
104 if (test_and_set_bit(0, &pnx833x_wdt_alive))
105 return -EBUSY;
106
107 if (nowayout)
108 __module_get(THIS_MODULE);
109
110 /* Activate timer */
111 if (!start_enabled)
112 pnx833x_wdt_start();
113
114 pnx833x_wdt_ping();
115
116 printk(KERN_INFO "Started watchdog timer.\n");
117
118 return nonseekable_open(inode, file);
119 }
120
pnx833x_wdt_release(struct inode * inode,struct file * file)121 static int pnx833x_wdt_release(struct inode *inode, struct file *file)
122 {
123 /* Shut off the timer.
124 * Lock it in if it's a module and we defined ...NOWAYOUT */
125 if (!nowayout)
126 pnx833x_wdt_stop(); /* Turn the WDT off */
127
128 clear_bit(0, &pnx833x_wdt_alive);
129 return 0;
130 }
131
pnx833x_wdt_write(struct file * file,const char * data,size_t len,loff_t * ppos)132 static ssize_t pnx833x_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
133 {
134 /* Refresh the timer. */
135 if (len)
136 pnx833x_wdt_ping();
137
138 return len;
139 }
140
pnx833x_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)141 static long pnx833x_wdt_ioctl(struct file *file, unsigned int cmd,
142 unsigned long arg)
143 {
144 int options, new_timeout = 0;
145 uint32_t timeout, timeout_left = 0;
146
147 static const struct watchdog_info ident = {
148 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
149 .firmware_version = 0,
150 .identity = "Hardware Watchdog for PNX833x",
151 };
152
153 switch (cmd) {
154 default:
155 return -ENOTTY;
156
157 case WDIOC_GETSUPPORT:
158 if (copy_to_user((struct watchdog_info *)arg,
159 &ident, sizeof(ident)))
160 return -EFAULT;
161 return 0;
162
163 case WDIOC_GETSTATUS:
164 case WDIOC_GETBOOTSTATUS:
165 return put_user(0, (int *)arg);
166
167 case WDIOC_SETOPTIONS:
168 if (get_user(options, (int *)arg))
169 return -EFAULT;
170
171 if (options & WDIOS_DISABLECARD)
172 pnx833x_wdt_stop();
173
174 if (options & WDIOS_ENABLECARD)
175 pnx833x_wdt_start();
176
177 return 0;
178
179 case WDIOC_KEEPALIVE:
180 pnx833x_wdt_ping();
181 return 0;
182
183 case WDIOC_SETTIMEOUT:
184 {
185 if (get_user(new_timeout, (int *)arg))
186 return -EFAULT;
187
188 pnx833x_wdt_timeout = new_timeout;
189 PNX833X_REG(PNX833X_CONFIG +
190 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = new_timeout;
191 return put_user(new_timeout, (int *)arg);
192 }
193
194 case WDIOC_GETTIMEOUT:
195 timeout = PNX833X_REG(PNX833X_CONFIG +
196 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE);
197 return put_user(timeout, (int *)arg);
198
199 case WDIOC_GETTIMELEFT:
200 timeout_left = PNX833X_REG(PNX833X_CONFIG +
201 PNX833X_CONFIG_CPU_WATCHDOG);
202 return put_user(timeout_left, (int *)arg);
203
204 }
205 }
206
pnx833x_wdt_notify_sys(struct notifier_block * this,unsigned long code,void * unused)207 static int pnx833x_wdt_notify_sys(struct notifier_block *this,
208 unsigned long code, void *unused)
209 {
210 if (code == SYS_DOWN || code == SYS_HALT)
211 pnx833x_wdt_stop(); /* Turn the WDT off */
212
213 return NOTIFY_DONE;
214 }
215
216 static const struct file_operations pnx833x_wdt_fops = {
217 .owner = THIS_MODULE,
218 .llseek = no_llseek,
219 .write = pnx833x_wdt_write,
220 .unlocked_ioctl = pnx833x_wdt_ioctl,
221 .open = pnx833x_wdt_open,
222 .release = pnx833x_wdt_release,
223 };
224
225 static struct miscdevice pnx833x_wdt_miscdev = {
226 .minor = WATCHDOG_MINOR,
227 .name = "watchdog",
228 .fops = &pnx833x_wdt_fops,
229 };
230
231 static struct notifier_block pnx833x_wdt_notifier = {
232 .notifier_call = pnx833x_wdt_notify_sys,
233 };
234
235 static char banner[] __initdata =
236 KERN_INFO PFX "Hardware Watchdog Timer for PNX833x: Version 0.1\n";
237
watchdog_init(void)238 static int __init watchdog_init(void)
239 {
240 int ret, cause;
241
242 /* Lets check the reason for the reset.*/
243 cause = PNX833X_REG(PNX833X_RESET);
244 /*If bit 31 is set then watchdog was cause of reset.*/
245 if (cause & 0x80000000) {
246 printk(KERN_INFO PFX "The system was previously reset due to "
247 "the watchdog firing - please investigate...\n");
248 }
249
250 ret = register_reboot_notifier(&pnx833x_wdt_notifier);
251 if (ret) {
252 printk(KERN_ERR PFX
253 "cannot register reboot notifier (err=%d)\n", ret);
254 return ret;
255 }
256
257 ret = misc_register(&pnx833x_wdt_miscdev);
258 if (ret) {
259 printk(KERN_ERR PFX
260 "cannot register miscdev on minor=%d (err=%d)\n",
261 WATCHDOG_MINOR, ret);
262 unregister_reboot_notifier(&pnx833x_wdt_notifier);
263 return ret;
264 }
265
266 printk(banner);
267 if (start_enabled)
268 pnx833x_wdt_start();
269
270 return 0;
271 }
272
watchdog_exit(void)273 static void __exit watchdog_exit(void)
274 {
275 misc_deregister(&pnx833x_wdt_miscdev);
276 unregister_reboot_notifier(&pnx833x_wdt_notifier);
277 }
278
279 module_init(watchdog_init);
280 module_exit(watchdog_exit);
281
282 MODULE_AUTHOR("Daniel Laird/Andre McCurdy");
283 MODULE_DESCRIPTION("Hardware Watchdog Device for PNX833x");
284 MODULE_LICENSE("GPL");
285 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
286