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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28
29 #include <linux/module.h>
30 #include <linux/kernel.h>
31 #include <linux/fs.h>
32 #include <linux/init.h>
33 #include <linux/device.h>
34 #include <linux/miscdevice.h>
35 #include <linux/watchdog.h>
36 #include <linux/uaccess.h>
37 #include <mach/hardware.h>
38
39 static bool nowayout = WATCHDOG_NOWAYOUT;
40 static unsigned long wdt_status;
41 static unsigned long boot_status;
42 static DEFINE_SPINLOCK(wdt_lock);
43
44 #define WDT_IN_USE 0
45 #define WDT_OK_TO_CLOSE 1
46 #define WDT_ENABLED 2
47
iop_watchdog_timeout(void)48 static unsigned long iop_watchdog_timeout(void)
49 {
50 return (0xffffffffUL / get_iop_tick_rate());
51 }
52
53 /**
54 * wdt_supports_disable - determine if we are accessing a iop13xx watchdog
55 * or iop3xx by whether it has a disable command
56 */
wdt_supports_disable(void)57 static int wdt_supports_disable(void)
58 {
59 int can_disable;
60
61 if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM)
62 can_disable = 1;
63 else
64 can_disable = 0;
65
66 return can_disable;
67 }
68
wdt_enable(void)69 static void wdt_enable(void)
70 {
71 /* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF
72 * Takes approx. 10.7s to timeout
73 */
74 spin_lock(&wdt_lock);
75 write_wdtcr(IOP_WDTCR_EN_ARM);
76 write_wdtcr(IOP_WDTCR_EN);
77 spin_unlock(&wdt_lock);
78 }
79
80 /* returns 0 if the timer was successfully disabled */
wdt_disable(void)81 static int wdt_disable(void)
82 {
83 /* Stop Counting */
84 if (wdt_supports_disable()) {
85 spin_lock(&wdt_lock);
86 write_wdtcr(IOP_WDTCR_DIS_ARM);
87 write_wdtcr(IOP_WDTCR_DIS);
88 clear_bit(WDT_ENABLED, &wdt_status);
89 spin_unlock(&wdt_lock);
90 pr_info("Disabled\n");
91 return 0;
92 } else
93 return 1;
94 }
95
iop_wdt_open(struct inode * inode,struct file * file)96 static int iop_wdt_open(struct inode *inode, struct file *file)
97 {
98 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
99 return -EBUSY;
100
101 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
102 wdt_enable();
103 set_bit(WDT_ENABLED, &wdt_status);
104 return nonseekable_open(inode, file);
105 }
106
iop_wdt_write(struct file * file,const char * data,size_t len,loff_t * ppos)107 static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len,
108 loff_t *ppos)
109 {
110 if (len) {
111 if (!nowayout) {
112 size_t i;
113
114 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
115
116 for (i = 0; i != len; i++) {
117 char c;
118
119 if (get_user(c, data + i))
120 return -EFAULT;
121 if (c == 'V')
122 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
123 }
124 }
125 wdt_enable();
126 }
127 return len;
128 }
129
130 static const struct watchdog_info ident = {
131 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
132 .identity = "iop watchdog",
133 };
134
iop_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)135 static long iop_wdt_ioctl(struct file *file,
136 unsigned int cmd, unsigned long arg)
137 {
138 int options;
139 int ret = -ENOTTY;
140 int __user *argp = (int __user *)arg;
141
142 switch (cmd) {
143 case WDIOC_GETSUPPORT:
144 if (copy_to_user(argp, &ident, sizeof(ident)))
145 ret = -EFAULT;
146 else
147 ret = 0;
148 break;
149
150 case WDIOC_GETSTATUS:
151 ret = put_user(0, argp);
152 break;
153
154 case WDIOC_GETBOOTSTATUS:
155 ret = put_user(boot_status, argp);
156 break;
157
158 case WDIOC_SETOPTIONS:
159 if (get_user(options, (int *)arg))
160 return -EFAULT;
161
162 if (options & WDIOS_DISABLECARD) {
163 if (!nowayout) {
164 if (wdt_disable() == 0) {
165 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
166 ret = 0;
167 } else
168 ret = -ENXIO;
169 } else
170 ret = 0;
171 }
172 if (options & WDIOS_ENABLECARD) {
173 wdt_enable();
174 ret = 0;
175 }
176 break;
177
178 case WDIOC_KEEPALIVE:
179 wdt_enable();
180 ret = 0;
181 break;
182
183 case WDIOC_GETTIMEOUT:
184 ret = put_user(iop_watchdog_timeout(), argp);
185 break;
186 }
187 return ret;
188 }
189
iop_wdt_release(struct inode * inode,struct file * file)190 static int iop_wdt_release(struct inode *inode, struct file *file)
191 {
192 int state = 1;
193 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
194 if (test_bit(WDT_ENABLED, &wdt_status))
195 state = wdt_disable();
196
197 /* if the timer is not disabled reload and notify that we are still
198 * going down
199 */
200 if (state != 0) {
201 wdt_enable();
202 pr_crit("Device closed unexpectedly - reset in %lu seconds\n",
203 iop_watchdog_timeout());
204 }
205
206 clear_bit(WDT_IN_USE, &wdt_status);
207 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
208
209 return 0;
210 }
211
212 static const struct file_operations iop_wdt_fops = {
213 .owner = THIS_MODULE,
214 .llseek = no_llseek,
215 .write = iop_wdt_write,
216 .unlocked_ioctl = iop_wdt_ioctl,
217 .open = iop_wdt_open,
218 .release = iop_wdt_release,
219 };
220
221 static struct miscdevice iop_wdt_miscdev = {
222 .minor = WATCHDOG_MINOR,
223 .name = "watchdog",
224 .fops = &iop_wdt_fops,
225 };
226
iop_wdt_init(void)227 static int __init iop_wdt_init(void)
228 {
229 int ret;
230
231 /* check if the reset was caused by the watchdog timer */
232 boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0;
233
234 /* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset
235 * NOTE: An IB Reset will Reset both cores in the IOP342
236 */
237 write_wdtsr(IOP13XX_WDTCR_IB_RESET);
238
239 /* Register after we have the device set up so we cannot race
240 with an open */
241 ret = misc_register(&iop_wdt_miscdev);
242 if (ret == 0)
243 pr_info("timeout %lu sec\n", iop_watchdog_timeout());
244
245 return ret;
246 }
247
iop_wdt_exit(void)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, bool, 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