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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
Joe Perches27c766a2012-02-15 15:06:19 -080027#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28
Dan Williams70c14ff2007-07-20 02:07:26 +010029#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>
Russell Kinga09e64f2008-08-05 16:14:15 +010037#include <mach/hardware.h>
Dan Williams70c14ff2007-07-20 02:07:26 +010038
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010039static bool nowayout = WATCHDOG_NOWAYOUT;
Dan Williams70c14ff2007-07-20 02:07:26 +010040static unsigned long wdt_status;
41static unsigned long boot_status;
Axel Lin1334f322011-11-29 13:54:01 +080042static DEFINE_SPINLOCK(wdt_lock);
Dan Williams70c14ff2007-07-20 02:07:26 +010043
44#define WDT_IN_USE 0
45#define WDT_OK_TO_CLOSE 1
46#define WDT_ENABLED 2
47
48static 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 */
57static 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
69static 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 */
Alan Cox02e38142008-05-19 14:06:14 +010074 spin_lock(&wdt_lock);
Dan Williams70c14ff2007-07-20 02:07:26 +010075 write_wdtcr(IOP_WDTCR_EN_ARM);
76 write_wdtcr(IOP_WDTCR_EN);
Alan Cox02e38142008-05-19 14:06:14 +010077 spin_unlock(&wdt_lock);
Dan Williams70c14ff2007-07-20 02:07:26 +010078}
79
80/* returns 0 if the timer was successfully disabled */
81static int wdt_disable(void)
82{
83 /* Stop Counting */
84 if (wdt_supports_disable()) {
Alan Cox02e38142008-05-19 14:06:14 +010085 spin_lock(&wdt_lock);
Dan Williams70c14ff2007-07-20 02:07:26 +010086 write_wdtcr(IOP_WDTCR_DIS_ARM);
87 write_wdtcr(IOP_WDTCR_DIS);
88 clear_bit(WDT_ENABLED, &wdt_status);
Alan Cox02e38142008-05-19 14:06:14 +010089 spin_unlock(&wdt_lock);
Joe Perches27c766a2012-02-15 15:06:19 -080090 pr_info("Disabled\n");
Dan Williams70c14ff2007-07-20 02:07:26 +010091 return 0;
92 } else
93 return 1;
94}
95
96static 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);
Dan Williams70c14ff2007-07-20 02:07:26 +0100102 wdt_enable();
Dan Williams70c14ff2007-07-20 02:07:26 +0100103 set_bit(WDT_ENABLED, &wdt_status);
Dan Williams70c14ff2007-07-20 02:07:26 +0100104 return nonseekable_open(inode, file);
105}
106
Alan Cox02e38142008-05-19 14:06:14 +0100107static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len,
Dan Williams70c14ff2007-07-20 02:07:26 +0100108 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 }
Dan Williams70c14ff2007-07-20 02:07:26 +0100127 return len;
128}
129
Alan Cox02e38142008-05-19 14:06:14 +0100130static const struct watchdog_info ident = {
Dan Williams70c14ff2007-07-20 02:07:26 +0100131 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
132 .identity = "iop watchdog",
133};
134
Alan Cox02e38142008-05-19 14:06:14 +0100135static long iop_wdt_ioctl(struct file *file,
136 unsigned int cmd, unsigned long arg)
Dan Williams70c14ff2007-07-20 02:07:26 +0100137{
138 int options;
139 int ret = -ENOTTY;
Alan Cox02e38142008-05-19 14:06:14 +0100140 int __user *argp = (int __user *)arg;
Dan Williams70c14ff2007-07-20 02:07:26 +0100141
142 switch (cmd) {
143 case WDIOC_GETSUPPORT:
Wim Van Sebroecke04ab952009-09-02 09:10:07 +0000144 if (copy_to_user(argp, &ident, sizeof(ident)))
Dan Williams70c14ff2007-07-20 02:07:26 +0100145 ret = -EFAULT;
146 else
147 ret = 0;
148 break;
149
150 case WDIOC_GETSTATUS:
Alan Cox02e38142008-05-19 14:06:14 +0100151 ret = put_user(0, argp);
Dan Williams70c14ff2007-07-20 02:07:26 +0100152 break;
153
154 case WDIOC_GETBOOTSTATUS:
Alan Cox02e38142008-05-19 14:06:14 +0100155 ret = put_user(boot_status, argp);
Dan Williams70c14ff2007-07-20 02:07:26 +0100156 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 }
Dan Williams70c14ff2007-07-20 02:07:26 +0100172 if (options & WDIOS_ENABLECARD) {
173 wdt_enable();
174 ret = 0;
175 }
176 break;
Dan Williams70c14ff2007-07-20 02:07:26 +0100177
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000178 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;
Dan Williams70c14ff2007-07-20 02:07:26 +0100186 }
Dan Williams70c14ff2007-07-20 02:07:26 +0100187 return ret;
188}
189
190static 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
Thadeu Lima de Souza Cascardo4b512d22009-04-14 23:14:10 -0300197 /* if the timer is not disabled reload and notify that we are still
Dan Williams70c14ff2007-07-20 02:07:26 +0100198 * going down
199 */
200 if (state != 0) {
201 wdt_enable();
Joe Perches27c766a2012-02-15 15:06:19 -0800202 pr_crit("Device closed unexpectedly - reset in %lu seconds\n",
203 iop_watchdog_timeout());
Dan Williams70c14ff2007-07-20 02:07:26 +0100204 }
205
206 clear_bit(WDT_IN_USE, &wdt_status);
207 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
208
209 return 0;
210}
211
212static const struct file_operations iop_wdt_fops = {
213 .owner = THIS_MODULE,
214 .llseek = no_llseek,
215 .write = iop_wdt_write,
Alan Cox02e38142008-05-19 14:06:14 +0100216 .unlocked_ioctl = iop_wdt_ioctl,
Dan Williams70c14ff2007-07-20 02:07:26 +0100217 .open = iop_wdt_open,
218 .release = iop_wdt_release,
219};
220
221static struct miscdevice iop_wdt_miscdev = {
222 .minor = WATCHDOG_MINOR,
223 .name = "watchdog",
224 .fops = &iop_wdt_fops,
225};
226
227static int __init iop_wdt_init(void)
228{
229 int ret;
230
Dan Williams70c14ff2007-07-20 02:07:26 +0100231 /* 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
Alan Cox02e38142008-05-19 14:06:14 +0100239 /* 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)
Joe Perches27c766a2012-02-15 15:06:19 -0800243 pr_info("timeout %lu sec\n", iop_watchdog_timeout());
Alan Cox02e38142008-05-19 14:06:14 +0100244
Dan Williams70c14ff2007-07-20 02:07:26 +0100245 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
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +0100256module_param(nowayout, bool, 0);
Dan Williams70c14ff2007-07-20 02:07:26 +0100257MODULE_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);