2 * drivers/char/watchdog/iop_wdt.c
4 * WDT driver for Intel I/O Processors
5 * Copyright (C) 2005, Intel Corporation.
7 * Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc.
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.
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
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.
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>
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29 #include <linux/module.h>
30 #include <linux/kernel.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>
39 static bool nowayout
= WATCHDOG_NOWAYOUT
;
40 static unsigned long wdt_status
;
41 static unsigned long boot_status
;
42 static DEFINE_SPINLOCK(wdt_lock
);
45 #define WDT_OK_TO_CLOSE 1
48 static unsigned long iop_watchdog_timeout(void)
50 return (0xffffffffUL
/ get_iop_tick_rate());
54 * wdt_supports_disable - determine if we are accessing a iop13xx watchdog
55 * or iop3xx by whether it has a disable command
57 static int wdt_supports_disable(void)
61 if (IOP_WDTCR_EN_ARM
!= IOP_WDTCR_DIS_ARM
)
69 static void wdt_enable(void)
71 /* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF
72 * Takes approx. 10.7s to timeout
75 write_wdtcr(IOP_WDTCR_EN_ARM
);
76 write_wdtcr(IOP_WDTCR_EN
);
77 spin_unlock(&wdt_lock
);
80 /* returns 0 if the timer was successfully disabled */
81 static int wdt_disable(void)
84 if (wdt_supports_disable()) {
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");
96 static int iop_wdt_open(struct inode
*inode
, struct file
*file
)
98 if (test_and_set_bit(WDT_IN_USE
, &wdt_status
))
101 clear_bit(WDT_OK_TO_CLOSE
, &wdt_status
);
103 set_bit(WDT_ENABLED
, &wdt_status
);
104 return nonseekable_open(inode
, file
);
107 static ssize_t
iop_wdt_write(struct file
*file
, const char *data
, size_t len
,
114 clear_bit(WDT_OK_TO_CLOSE
, &wdt_status
);
116 for (i
= 0; i
!= len
; i
++) {
119 if (get_user(c
, data
+ i
))
122 set_bit(WDT_OK_TO_CLOSE
, &wdt_status
);
130 static const struct watchdog_info ident
= {
131 .options
= WDIOF_CARDRESET
| WDIOF_MAGICCLOSE
| WDIOF_KEEPALIVEPING
,
132 .identity
= "iop watchdog",
135 static long iop_wdt_ioctl(struct file
*file
,
136 unsigned int cmd
, unsigned long arg
)
140 int __user
*argp
= (int __user
*)arg
;
143 case WDIOC_GETSUPPORT
:
144 if (copy_to_user(argp
, &ident
, sizeof(ident
)))
150 case WDIOC_GETSTATUS
:
151 ret
= put_user(0, argp
);
154 case WDIOC_GETBOOTSTATUS
:
155 ret
= put_user(boot_status
, argp
);
158 case WDIOC_SETOPTIONS
:
159 if (get_user(options
, (int *)arg
))
162 if (options
& WDIOS_DISABLECARD
) {
164 if (wdt_disable() == 0) {
165 set_bit(WDT_OK_TO_CLOSE
, &wdt_status
);
172 if (options
& WDIOS_ENABLECARD
) {
178 case WDIOC_KEEPALIVE
:
183 case WDIOC_GETTIMEOUT
:
184 ret
= put_user(iop_watchdog_timeout(), argp
);
190 static int iop_wdt_release(struct inode
*inode
, struct file
*file
)
193 if (test_bit(WDT_OK_TO_CLOSE
, &wdt_status
))
194 if (test_bit(WDT_ENABLED
, &wdt_status
))
195 state
= wdt_disable();
197 /* if the timer is not disabled reload and notify that we are still
202 pr_crit("Device closed unexpectedly - reset in %lu seconds\n",
203 iop_watchdog_timeout());
206 clear_bit(WDT_IN_USE
, &wdt_status
);
207 clear_bit(WDT_OK_TO_CLOSE
, &wdt_status
);
212 static const struct file_operations iop_wdt_fops
= {
213 .owner
= THIS_MODULE
,
215 .write
= iop_wdt_write
,
216 .unlocked_ioctl
= iop_wdt_ioctl
,
217 .open
= iop_wdt_open
,
218 .release
= iop_wdt_release
,
221 static struct miscdevice iop_wdt_miscdev
= {
222 .minor
= WATCHDOG_MINOR
,
224 .fops
= &iop_wdt_fops
,
227 static int __init
iop_wdt_init(void)
231 /* check if the reset was caused by the watchdog timer */
232 boot_status
= (read_rcsr() & IOP_RCSR_WDT
) ? WDIOF_CARDRESET
: 0;
234 /* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset
235 * NOTE: An IB Reset will Reset both cores in the IOP342
237 write_wdtsr(IOP13XX_WDTCR_IB_RESET
);
239 /* Register after we have the device set up so we cannot race
241 ret
= misc_register(&iop_wdt_miscdev
);
243 pr_info("timeout %lu sec\n", iop_watchdog_timeout());
248 static void __exit
iop_wdt_exit(void)
250 misc_deregister(&iop_wdt_miscdev
);
253 module_init(iop_wdt_init
);
254 module_exit(iop_wdt_exit
);
256 module_param(nowayout
, bool, 0);
257 MODULE_PARM_DESC(nowayout
, "Watchdog cannot be stopped once started");
259 MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>");
260 MODULE_DESCRIPTION("iop watchdog timer driver");
261 MODULE_LICENSE("GPL");