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1 | /* |
2 | * drivers/char/watchdog/iop_wdt.c | |
3 | * | |
4 | * WDT driver for Intel I/O Processors | |
5 | * Copyright (C) 2005, Intel Corporation. | |
6 | * | |
7 | * Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify it | |
10 | * under the terms and conditions of the GNU General Public License, | |
11 | * version 2, as published by the Free Software Foundation. | |
12 | * | |
13 | * This program is distributed in the hope it will be useful, but WITHOUT | |
14 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
16 | * more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License along with | |
19 | * this program; if not, write to the Free Software Foundation, Inc., 59 Temple | |
20 | * Place - Suite 330, Boston, MA 02111-1307 USA. | |
21 | * | |
22 | * Curt E Bruns <curt.e.bruns@intel.com> | |
23 | * Peter Milne <peter.milne@d-tacq.com> | |
24 | * Dan Williams <dan.j.williams@intel.com> | |
25 | */ | |
26 | ||
27 | #include <linux/module.h> | |
28 | #include <linux/kernel.h> | |
29 | #include <linux/fs.h> | |
30 | #include <linux/init.h> | |
31 | #include <linux/device.h> | |
32 | #include <linux/miscdevice.h> | |
33 | #include <linux/watchdog.h> | |
34 | #include <linux/uaccess.h> | |
35 | #include <asm/hardware.h> | |
36 | ||
37 | static int nowayout = WATCHDOG_NOWAYOUT; | |
38 | static unsigned long wdt_status; | |
39 | static unsigned long boot_status; | |
40 | ||
41 | #define WDT_IN_USE 0 | |
42 | #define WDT_OK_TO_CLOSE 1 | |
43 | #define WDT_ENABLED 2 | |
44 | ||
45 | static unsigned long iop_watchdog_timeout(void) | |
46 | { | |
47 | return (0xffffffffUL / get_iop_tick_rate()); | |
48 | } | |
49 | ||
50 | /** | |
51 | * wdt_supports_disable - determine if we are accessing a iop13xx watchdog | |
52 | * or iop3xx by whether it has a disable command | |
53 | */ | |
54 | static int wdt_supports_disable(void) | |
55 | { | |
56 | int can_disable; | |
57 | ||
58 | if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM) | |
59 | can_disable = 1; | |
60 | else | |
61 | can_disable = 0; | |
62 | ||
63 | return can_disable; | |
64 | } | |
65 | ||
66 | static void wdt_enable(void) | |
67 | { | |
68 | /* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF | |
69 | * Takes approx. 10.7s to timeout | |
70 | */ | |
71 | write_wdtcr(IOP_WDTCR_EN_ARM); | |
72 | write_wdtcr(IOP_WDTCR_EN); | |
73 | } | |
74 | ||
75 | /* returns 0 if the timer was successfully disabled */ | |
76 | static int wdt_disable(void) | |
77 | { | |
78 | /* Stop Counting */ | |
79 | if (wdt_supports_disable()) { | |
80 | write_wdtcr(IOP_WDTCR_DIS_ARM); | |
81 | write_wdtcr(IOP_WDTCR_DIS); | |
82 | clear_bit(WDT_ENABLED, &wdt_status); | |
83 | printk(KERN_INFO "WATCHDOG: Disabled\n"); | |
84 | return 0; | |
85 | } else | |
86 | return 1; | |
87 | } | |
88 | ||
89 | static int iop_wdt_open(struct inode *inode, struct file *file) | |
90 | { | |
91 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) | |
92 | return -EBUSY; | |
93 | ||
94 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
95 | ||
96 | wdt_enable(); | |
97 | ||
98 | set_bit(WDT_ENABLED, &wdt_status); | |
99 | ||
100 | return nonseekable_open(inode, file); | |
101 | } | |
102 | ||
103 | static ssize_t | |
104 | iop_wdt_write(struct file *file, const char *data, size_t len, | |
105 | loff_t *ppos) | |
106 | { | |
107 | if (len) { | |
108 | if (!nowayout) { | |
109 | size_t i; | |
110 | ||
111 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
112 | ||
113 | for (i = 0; i != len; i++) { | |
114 | char c; | |
115 | ||
116 | if (get_user(c, data + i)) | |
117 | return -EFAULT; | |
118 | if (c == 'V') | |
119 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
120 | } | |
121 | } | |
122 | wdt_enable(); | |
123 | } | |
124 | ||
125 | return len; | |
126 | } | |
127 | ||
128 | static struct watchdog_info ident = { | |
129 | .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, | |
130 | .identity = "iop watchdog", | |
131 | }; | |
132 | ||
133 | static int | |
134 | iop_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
135 | unsigned long arg) | |
136 | { | |
137 | int options; | |
138 | int ret = -ENOTTY; | |
139 | ||
140 | switch (cmd) { | |
141 | case WDIOC_GETSUPPORT: | |
142 | if (copy_to_user | |
143 | ((struct watchdog_info *)arg, &ident, sizeof ident)) | |
144 | ret = -EFAULT; | |
145 | else | |
146 | ret = 0; | |
147 | break; | |
148 | ||
149 | case WDIOC_GETSTATUS: | |
150 | ret = put_user(0, (int *)arg); | |
151 | break; | |
152 | ||
153 | case WDIOC_GETBOOTSTATUS: | |
154 | ret = put_user(boot_status, (int *)arg); | |
155 | break; | |
156 | ||
157 | case WDIOC_GETTIMEOUT: | |
158 | ret = put_user(iop_watchdog_timeout(), (int *)arg); | |
159 | break; | |
160 | ||
161 | case WDIOC_KEEPALIVE: | |
162 | wdt_enable(); | |
163 | ret = 0; | |
164 | break; | |
165 | ||
166 | case WDIOC_SETOPTIONS: | |
167 | if (get_user(options, (int *)arg)) | |
168 | return -EFAULT; | |
169 | ||
170 | if (options & WDIOS_DISABLECARD) { | |
171 | if (!nowayout) { | |
172 | if (wdt_disable() == 0) { | |
173 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
174 | ret = 0; | |
175 | } else | |
176 | ret = -ENXIO; | |
177 | } else | |
178 | ret = 0; | |
179 | } | |
180 | ||
181 | if (options & WDIOS_ENABLECARD) { | |
182 | wdt_enable(); | |
183 | ret = 0; | |
184 | } | |
185 | break; | |
186 | } | |
187 | ||
188 | return ret; | |
189 | } | |
190 | ||
191 | static int iop_wdt_release(struct inode *inode, struct file *file) | |
192 | { | |
193 | int state = 1; | |
194 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) | |
195 | if (test_bit(WDT_ENABLED, &wdt_status)) | |
196 | state = wdt_disable(); | |
197 | ||
198 | /* if the timer is not disbaled reload and notify that we are still | |
199 | * going down | |
200 | */ | |
201 | if (state != 0) { | |
202 | wdt_enable(); | |
203 | printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - " | |
204 | "reset in %lu seconds\n", iop_watchdog_timeout()); | |
205 | } | |
206 | ||
207 | clear_bit(WDT_IN_USE, &wdt_status); | |
208 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
209 | ||
210 | return 0; | |
211 | } | |
212 | ||
213 | static const struct file_operations iop_wdt_fops = { | |
214 | .owner = THIS_MODULE, | |
215 | .llseek = no_llseek, | |
216 | .write = iop_wdt_write, | |
217 | .ioctl = iop_wdt_ioctl, | |
218 | .open = iop_wdt_open, | |
219 | .release = iop_wdt_release, | |
220 | }; | |
221 | ||
222 | static struct miscdevice iop_wdt_miscdev = { | |
223 | .minor = WATCHDOG_MINOR, | |
224 | .name = "watchdog", | |
225 | .fops = &iop_wdt_fops, | |
226 | }; | |
227 | ||
228 | static int __init iop_wdt_init(void) | |
229 | { | |
230 | int ret; | |
231 | ||
232 | ret = misc_register(&iop_wdt_miscdev); | |
233 | if (ret == 0) | |
234 | printk("iop watchdog timer: timeout %lu sec\n", | |
235 | iop_watchdog_timeout()); | |
236 | ||
237 | /* check if the reset was caused by the watchdog timer */ | |
238 | boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0; | |
239 | ||
240 | /* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset | |
241 | * NOTE: An IB Reset will Reset both cores in the IOP342 | |
242 | */ | |
243 | write_wdtsr(IOP13XX_WDTCR_IB_RESET); | |
244 | ||
245 | return ret; | |
246 | } | |
247 | ||
248 | static void __exit iop_wdt_exit(void) | |
249 | { | |
250 | misc_deregister(&iop_wdt_miscdev); | |
251 | } | |
252 | ||
253 | module_init(iop_wdt_init); | |
254 | module_exit(iop_wdt_exit); | |
255 | ||
256 | module_param(nowayout, int, 0); | |
257 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); | |
258 | ||
259 | MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>"); | |
260 | MODULE_DESCRIPTION("iop watchdog timer driver"); | |
261 | MODULE_LICENSE("GPL"); | |
262 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |