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