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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 <mach/hardware.h> |
36 | |
37 | static int nowayout = WATCHDOG_NOWAYOUT; |
38 | static unsigned long wdt_status; |
39 | static unsigned long boot_status; |
40 | static spinlock_t wdt_lock; |
41 | |
42 | #define WDT_IN_USE 0 |
43 | #define WDT_OK_TO_CLOSE 1 |
44 | #define WDT_ENABLED 2 |
45 | |
46 | static unsigned long iop_watchdog_timeout(void) |
47 | { |
48 | return (0xffffffffUL / get_iop_tick_rate()); |
49 | } |
50 | |
51 | /** |
52 | * wdt_supports_disable - determine if we are accessing a iop13xx watchdog |
53 | * or iop3xx by whether it has a disable command |
54 | */ |
55 | static int wdt_supports_disable(void) |
56 | { |
57 | int can_disable; |
58 | |
59 | if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM) |
60 | can_disable = 1; |
61 | else |
62 | can_disable = 0; |
63 | |
64 | return can_disable; |
65 | } |
66 | |
67 | static void wdt_enable(void) |
68 | { |
69 | /* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF |
70 | * Takes approx. 10.7s to timeout |
71 | */ |
72 | spin_lock(&wdt_lock); |
73 | write_wdtcr(IOP_WDTCR_EN_ARM); |
74 | write_wdtcr(IOP_WDTCR_EN); |
75 | spin_unlock(&wdt_lock); |
76 | } |
77 | |
78 | /* returns 0 if the timer was successfully disabled */ |
79 | static int wdt_disable(void) |
80 | { |
81 | /* Stop Counting */ |
82 | if (wdt_supports_disable()) { |
83 | spin_lock(&wdt_lock); |
84 | write_wdtcr(IOP_WDTCR_DIS_ARM); |
85 | write_wdtcr(IOP_WDTCR_DIS); |
86 | clear_bit(WDT_ENABLED, &wdt_status); |
87 | spin_unlock(&wdt_lock); |
88 | printk(KERN_INFO "WATCHDOG: Disabled\n"); |
89 | return 0; |
90 | } else |
91 | return 1; |
92 | } |
93 | |
94 | static int iop_wdt_open(struct inode *inode, struct file *file) |
95 | { |
96 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
97 | return -EBUSY; |
98 | |
99 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
100 | wdt_enable(); |
101 | set_bit(WDT_ENABLED, &wdt_status); |
102 | return nonseekable_open(inode, file); |
103 | } |
104 | |
105 | static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len, |
106 | loff_t *ppos) |
107 | { |
108 | if (len) { |
109 | if (!nowayout) { |
110 | size_t i; |
111 | |
112 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
113 | |
114 | for (i = 0; i != len; i++) { |
115 | char c; |
116 | |
117 | if (get_user(c, data + i)) |
118 | return -EFAULT; |
119 | if (c == 'V') |
120 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
121 | } |
122 | } |
123 | wdt_enable(); |
124 | } |
125 | return len; |
126 | } |
127 | |
128 | static const struct watchdog_info ident = { |
129 | .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, |
130 | .identity = "iop watchdog", |
131 | }; |
132 | |
133 | static long iop_wdt_ioctl(struct file *file, |
134 | unsigned int cmd, unsigned long arg) |
135 | { |
136 | int options; |
137 | int ret = -ENOTTY; |
138 | int __user *argp = (int __user *)arg; |
139 | |
140 | switch (cmd) { |
141 | case WDIOC_GETSUPPORT: |
142 | if (copy_to_user(argp, &ident, sizeof(ident))) |
143 | ret = -EFAULT; |
144 | else |
145 | ret = 0; |
146 | break; |
147 | |
148 | case WDIOC_GETSTATUS: |
149 | ret = put_user(0, argp); |
150 | break; |
151 | |
152 | case WDIOC_GETBOOTSTATUS: |
153 | ret = put_user(boot_status, argp); |
154 | break; |
155 | |
156 | case WDIOC_SETOPTIONS: |
157 | if (get_user(options, (int *)arg)) |
158 | return -EFAULT; |
159 | |
160 | if (options & WDIOS_DISABLECARD) { |
161 | if (!nowayout) { |
162 | if (wdt_disable() == 0) { |
163 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
164 | ret = 0; |
165 | } else |
166 | ret = -ENXIO; |
167 | } else |
168 | ret = 0; |
169 | } |
170 | if (options & WDIOS_ENABLECARD) { |
171 | wdt_enable(); |
172 | ret = 0; |
173 | } |
174 | break; |
175 | |
176 | case WDIOC_KEEPALIVE: |
177 | wdt_enable(); |
178 | ret = 0; |
179 | break; |
180 | |
181 | case WDIOC_GETTIMEOUT: |
182 | ret = put_user(iop_watchdog_timeout(), argp); |
183 | break; |
184 | } |
185 | return ret; |
186 | } |
187 | |
188 | static int iop_wdt_release(struct inode *inode, struct file *file) |
189 | { |
190 | int state = 1; |
191 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) |
192 | if (test_bit(WDT_ENABLED, &wdt_status)) |
193 | state = wdt_disable(); |
194 | |
195 | /* if the timer is not disabled reload and notify that we are still |
196 | * going down |
197 | */ |
198 | if (state != 0) { |
199 | wdt_enable(); |
200 | printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - " |
201 | "reset in %lu seconds\n", iop_watchdog_timeout()); |
202 | } |
203 | |
204 | clear_bit(WDT_IN_USE, &wdt_status); |
205 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
206 | |
207 | return 0; |
208 | } |
209 | |
210 | static const struct file_operations iop_wdt_fops = { |
211 | .owner = THIS_MODULE, |
212 | .llseek = no_llseek, |
213 | .write = iop_wdt_write, |
214 | .unlocked_ioctl = iop_wdt_ioctl, |
215 | .open = iop_wdt_open, |
216 | .release = iop_wdt_release, |
217 | }; |
218 | |
219 | static struct miscdevice iop_wdt_miscdev = { |
220 | .minor = WATCHDOG_MINOR, |
221 | .name = "watchdog", |
222 | .fops = &iop_wdt_fops, |
223 | }; |
224 | |
225 | static int __init iop_wdt_init(void) |
226 | { |
227 | int ret; |
228 | |
229 | spin_lock_init(&wdt_lock); |
230 | |
231 | |
232 | /* check if the reset was caused by the watchdog timer */ |
233 | boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0; |
234 | |
235 | /* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset |
236 | * NOTE: An IB Reset will Reset both cores in the IOP342 |
237 | */ |
238 | write_wdtsr(IOP13XX_WDTCR_IB_RESET); |
239 | |
240 | /* Register after we have the device set up so we cannot race |
241 | with an open */ |
242 | ret = misc_register(&iop_wdt_miscdev); |
243 | if (ret == 0) |
244 | printk(KERN_INFO "iop watchdog timer: timeout %lu sec\n", |
245 | iop_watchdog_timeout()); |
246 | |
247 | return ret; |
248 | } |
249 | |
250 | static void __exit iop_wdt_exit(void) |
251 | { |
252 | misc_deregister(&iop_wdt_miscdev); |
253 | } |
254 | |
255 | module_init(iop_wdt_init); |
256 | module_exit(iop_wdt_exit); |
257 | |
258 | module_param(nowayout, int, 0); |
259 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
260 | |
261 | MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>"); |
262 | MODULE_DESCRIPTION("iop watchdog timer driver"); |
263 | MODULE_LICENSE("GPL"); |
264 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
265 |
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