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