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
iop_watchdog_timeout(void)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 */
wdt_supports_disable(void)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
wdt_enable(void)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 */
wdt_disable(void)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
iop_wdt_open(struct inode * inode,struct file * file)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
iop_wdt_write(struct file * file,const char * data,size_t len,loff_t * ppos)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
iop_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)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
iop_wdt_release(struct inode * inode,struct file * file)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
iop_wdt_init(void)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
iop_wdt_exit(void)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