blob: bbbd91af754dc4696e21be327b9884378f771449 [file] [log] [blame]
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>
35#include <asm/hardware.h>
36
37static int nowayout = WATCHDOG_NOWAYOUT;
38static unsigned long wdt_status;
39static unsigned long boot_status;
40
41#define WDT_IN_USE 0
42#define WDT_OK_TO_CLOSE 1
43#define WDT_ENABLED 2
44
45static 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 */
54static 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
66static 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 */
76static 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
89static 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
103static ssize_t
104iop_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
128static struct watchdog_info ident = {
129 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
130 .identity = "iop watchdog",
131};
132
133static int
134iop_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
191static 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
213static 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
222static struct miscdevice iop_wdt_miscdev = {
223 .minor = WATCHDOG_MINOR,
224 .name = "watchdog",
225 .fops = &iop_wdt_fops,
226};
227
228static 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
248static void __exit iop_wdt_exit(void)
249{
250 misc_deregister(&iop_wdt_miscdev);
251}
252
253module_init(iop_wdt_init);
254module_exit(iop_wdt_exit);
255
256module_param(nowayout, int, 0);
257MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
258
259MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>");
260MODULE_DESCRIPTION("iop watchdog timer driver");
261MODULE_LICENSE("GPL");
262MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);