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Dan Williams70c14ff2007-07-20 02:07:26 +01001/*
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>
Russell Kinga09e64f2008-08-05 16:14:15 +010035#include <mach/hardware.h>
Dan Williams70c14ff2007-07-20 02:07:26 +010036
37static int nowayout = WATCHDOG_NOWAYOUT;
38static unsigned long wdt_status;
39static unsigned long boot_status;
Alan Cox02e38142008-05-19 14:06:14 +010040static spinlock_t wdt_lock;
Dan Williams70c14ff2007-07-20 02:07:26 +010041
42#define WDT_IN_USE 0
43#define WDT_OK_TO_CLOSE 1
44#define WDT_ENABLED 2
45
46static 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 */
55static 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
67static 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 */
Alan Cox02e38142008-05-19 14:06:14 +010072 spin_lock(&wdt_lock);
Dan Williams70c14ff2007-07-20 02:07:26 +010073 write_wdtcr(IOP_WDTCR_EN_ARM);
74 write_wdtcr(IOP_WDTCR_EN);
Alan Cox02e38142008-05-19 14:06:14 +010075 spin_unlock(&wdt_lock);
Dan Williams70c14ff2007-07-20 02:07:26 +010076}
77
78/* returns 0 if the timer was successfully disabled */
79static int wdt_disable(void)
80{
81 /* Stop Counting */
82 if (wdt_supports_disable()) {
Alan Cox02e38142008-05-19 14:06:14 +010083 spin_lock(&wdt_lock);
Dan Williams70c14ff2007-07-20 02:07:26 +010084 write_wdtcr(IOP_WDTCR_DIS_ARM);
85 write_wdtcr(IOP_WDTCR_DIS);
86 clear_bit(WDT_ENABLED, &wdt_status);
Alan Cox02e38142008-05-19 14:06:14 +010087 spin_unlock(&wdt_lock);
Dan Williams70c14ff2007-07-20 02:07:26 +010088 printk(KERN_INFO "WATCHDOG: Disabled\n");
89 return 0;
90 } else
91 return 1;
92}
93
94static 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);
Dan Williams70c14ff2007-07-20 02:07:26 +0100100 wdt_enable();
Dan Williams70c14ff2007-07-20 02:07:26 +0100101 set_bit(WDT_ENABLED, &wdt_status);
Dan Williams70c14ff2007-07-20 02:07:26 +0100102 return nonseekable_open(inode, file);
103}
104
Alan Cox02e38142008-05-19 14:06:14 +0100105static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len,
Dan Williams70c14ff2007-07-20 02:07:26 +0100106 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 }
Dan Williams70c14ff2007-07-20 02:07:26 +0100125 return len;
126}
127
Alan Cox02e38142008-05-19 14:06:14 +0100128static const struct watchdog_info ident = {
Dan Williams70c14ff2007-07-20 02:07:26 +0100129 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
130 .identity = "iop watchdog",
131};
132
Alan Cox02e38142008-05-19 14:06:14 +0100133static long iop_wdt_ioctl(struct file *file,
134 unsigned int cmd, unsigned long arg)
Dan Williams70c14ff2007-07-20 02:07:26 +0100135{
136 int options;
137 int ret = -ENOTTY;
Alan Cox02e38142008-05-19 14:06:14 +0100138 int __user *argp = (int __user *)arg;
Dan Williams70c14ff2007-07-20 02:07:26 +0100139
140 switch (cmd) {
141 case WDIOC_GETSUPPORT:
Wim Van Sebroecke04ab952009-09-02 09:10:07 +0000142 if (copy_to_user(argp, &ident, sizeof(ident)))
Dan Williams70c14ff2007-07-20 02:07:26 +0100143 ret = -EFAULT;
144 else
145 ret = 0;
146 break;
147
148 case WDIOC_GETSTATUS:
Alan Cox02e38142008-05-19 14:06:14 +0100149 ret = put_user(0, argp);
Dan Williams70c14ff2007-07-20 02:07:26 +0100150 break;
151
152 case WDIOC_GETBOOTSTATUS:
Alan Cox02e38142008-05-19 14:06:14 +0100153 ret = put_user(boot_status, argp);
Dan Williams70c14ff2007-07-20 02:07:26 +0100154 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 }
Dan Williams70c14ff2007-07-20 02:07:26 +0100170 if (options & WDIOS_ENABLECARD) {
171 wdt_enable();
172 ret = 0;
173 }
174 break;
Dan Williams70c14ff2007-07-20 02:07:26 +0100175
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000176 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;
Dan Williams70c14ff2007-07-20 02:07:26 +0100184 }
Dan Williams70c14ff2007-07-20 02:07:26 +0100185 return ret;
186}
187
188static 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
Thadeu Lima de Souza Cascardo4b512d22009-04-14 23:14:10 -0300195 /* if the timer is not disabled reload and notify that we are still
Dan Williams70c14ff2007-07-20 02:07:26 +0100196 * 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
210static const struct file_operations iop_wdt_fops = {
211 .owner = THIS_MODULE,
212 .llseek = no_llseek,
213 .write = iop_wdt_write,
Alan Cox02e38142008-05-19 14:06:14 +0100214 .unlocked_ioctl = iop_wdt_ioctl,
Dan Williams70c14ff2007-07-20 02:07:26 +0100215 .open = iop_wdt_open,
216 .release = iop_wdt_release,
217};
218
219static struct miscdevice iop_wdt_miscdev = {
220 .minor = WATCHDOG_MINOR,
221 .name = "watchdog",
222 .fops = &iop_wdt_fops,
223};
224
225static int __init iop_wdt_init(void)
226{
227 int ret;
228
Alan Cox02e38142008-05-19 14:06:14 +0100229 spin_lock_init(&wdt_lock);
230
Dan Williams70c14ff2007-07-20 02:07:26 +0100231
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
Alan Cox02e38142008-05-19 14:06:14 +0100240 /* 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)
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000244 printk(KERN_INFO "iop watchdog timer: timeout %lu sec\n",
Alan Cox02e38142008-05-19 14:06:14 +0100245 iop_watchdog_timeout());
246
Dan Williams70c14ff2007-07-20 02:07:26 +0100247 return ret;
248}
249
250static void __exit iop_wdt_exit(void)
251{
252 misc_deregister(&iop_wdt_miscdev);
253}
254
255module_init(iop_wdt_init);
256module_exit(iop_wdt_exit);
257
258module_param(nowayout, int, 0);
259MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
260
261MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>");
262MODULE_DESCRIPTION("iop watchdog timer driver");
263MODULE_LICENSE("GPL");
264MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);