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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#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 <mach/hardware.h>
36
37static int nowayout = WATCHDOG_NOWAYOUT;
38static unsigned long wdt_status;
39static unsigned long boot_status;
40static spinlock_t wdt_lock;
41
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 */
72 spin_lock(&wdt_lock);
73 write_wdtcr(IOP_WDTCR_EN_ARM);
74 write_wdtcr(IOP_WDTCR_EN);
75 spin_unlock(&wdt_lock);
76}
77
78/* returns 0 if the timer was successfully disabled */
79static int wdt_disable(void)
80{
81 /* Stop Counting */
82 if (wdt_supports_disable()) {
83 spin_lock(&wdt_lock);
84 write_wdtcr(IOP_WDTCR_DIS_ARM);
85 write_wdtcr(IOP_WDTCR_DIS);
86 clear_bit(WDT_ENABLED, &wdt_status);
87 spin_unlock(&wdt_lock);
88 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);
100 wdt_enable();
101 set_bit(WDT_ENABLED, &wdt_status);
102 return nonseekable_open(inode, file);
103}
104
105static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len,
106 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 }
125 return len;
126}
127
128static const struct watchdog_info ident = {
129 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
130 .identity = "iop watchdog",
131};
132
133static long iop_wdt_ioctl(struct file *file,
134 unsigned int cmd, unsigned long arg)
135{
136 int options;
137 int ret = -ENOTTY;
138 int __user *argp = (int __user *)arg;
139
140 switch (cmd) {
141 case WDIOC_GETSUPPORT:
142 if (copy_to_user(argp, &ident, sizeof(ident)))
143 ret = -EFAULT;
144 else
145 ret = 0;
146 break;
147
148 case WDIOC_GETSTATUS:
149 ret = put_user(0, argp);
150 break;
151
152 case WDIOC_GETBOOTSTATUS:
153 ret = put_user(boot_status, argp);
154 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 }
170 if (options & WDIOS_ENABLECARD) {
171 wdt_enable();
172 ret = 0;
173 }
174 break;
175
176 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;
184 }
185 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
195 /* if the timer is not disabled reload and notify that we are still
196 * 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,
214 .unlocked_ioctl = iop_wdt_ioctl,
215 .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
229 spin_lock_init(&wdt_lock);
230
231
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
240 /* 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)
244 printk(KERN_INFO "iop watchdog timer: timeout %lu sec\n",
245 iop_watchdog_timeout());
246
247 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);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/char/watchdog/iop_wdt.c
4 *
5 * WDT driver for Intel I/O Processors
6 * Copyright (C) 2005, Intel Corporation.
7 *
8 * Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc.
9 *
10 * Curt E Bruns <curt.e.bruns@intel.com>
11 * Peter Milne <peter.milne@d-tacq.com>
12 * Dan Williams <dan.j.williams@intel.com>
13 */
14
15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include <linux/module.h>
18#include <linux/kernel.h>
19#include <linux/fs.h>
20#include <linux/init.h>
21#include <linux/device.h>
22#include <linux/miscdevice.h>
23#include <linux/watchdog.h>
24#include <linux/uaccess.h>
25#include <mach/hardware.h>
26
27static bool nowayout = WATCHDOG_NOWAYOUT;
28static unsigned long wdt_status;
29static unsigned long boot_status;
30static DEFINE_SPINLOCK(wdt_lock);
31
32#define WDT_IN_USE 0
33#define WDT_OK_TO_CLOSE 1
34#define WDT_ENABLED 2
35
36static unsigned long iop_watchdog_timeout(void)
37{
38 return (0xffffffffUL / get_iop_tick_rate());
39}
40
41/**
42 * wdt_supports_disable - determine if we are accessing a iop13xx watchdog
43 * or iop3xx by whether it has a disable command
44 */
45static int wdt_supports_disable(void)
46{
47 int can_disable;
48
49 if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM)
50 can_disable = 1;
51 else
52 can_disable = 0;
53
54 return can_disable;
55}
56
57static void wdt_enable(void)
58{
59 /* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF
60 * Takes approx. 10.7s to timeout
61 */
62 spin_lock(&wdt_lock);
63 write_wdtcr(IOP_WDTCR_EN_ARM);
64 write_wdtcr(IOP_WDTCR_EN);
65 spin_unlock(&wdt_lock);
66}
67
68/* returns 0 if the timer was successfully disabled */
69static int wdt_disable(void)
70{
71 /* Stop Counting */
72 if (wdt_supports_disable()) {
73 spin_lock(&wdt_lock);
74 write_wdtcr(IOP_WDTCR_DIS_ARM);
75 write_wdtcr(IOP_WDTCR_DIS);
76 clear_bit(WDT_ENABLED, &wdt_status);
77 spin_unlock(&wdt_lock);
78 pr_info("Disabled\n");
79 return 0;
80 } else
81 return 1;
82}
83
84static int iop_wdt_open(struct inode *inode, struct file *file)
85{
86 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
87 return -EBUSY;
88
89 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
90 wdt_enable();
91 set_bit(WDT_ENABLED, &wdt_status);
92 return stream_open(inode, file);
93}
94
95static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len,
96 loff_t *ppos)
97{
98 if (len) {
99 if (!nowayout) {
100 size_t i;
101
102 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
103
104 for (i = 0; i != len; i++) {
105 char c;
106
107 if (get_user(c, data + i))
108 return -EFAULT;
109 if (c == 'V')
110 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
111 }
112 }
113 wdt_enable();
114 }
115 return len;
116}
117
118static const struct watchdog_info ident = {
119 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
120 .identity = "iop watchdog",
121};
122
123static long iop_wdt_ioctl(struct file *file,
124 unsigned int cmd, unsigned long arg)
125{
126 int options;
127 int ret = -ENOTTY;
128 int __user *argp = (int __user *)arg;
129
130 switch (cmd) {
131 case WDIOC_GETSUPPORT:
132 if (copy_to_user(argp, &ident, sizeof(ident)))
133 ret = -EFAULT;
134 else
135 ret = 0;
136 break;
137
138 case WDIOC_GETSTATUS:
139 ret = put_user(0, argp);
140 break;
141
142 case WDIOC_GETBOOTSTATUS:
143 ret = put_user(boot_status, argp);
144 break;
145
146 case WDIOC_SETOPTIONS:
147 if (get_user(options, (int *)arg))
148 return -EFAULT;
149
150 if (options & WDIOS_DISABLECARD) {
151 if (!nowayout) {
152 if (wdt_disable() == 0) {
153 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
154 ret = 0;
155 } else
156 ret = -ENXIO;
157 } else
158 ret = 0;
159 }
160 if (options & WDIOS_ENABLECARD) {
161 wdt_enable();
162 ret = 0;
163 }
164 break;
165
166 case WDIOC_KEEPALIVE:
167 wdt_enable();
168 ret = 0;
169 break;
170
171 case WDIOC_GETTIMEOUT:
172 ret = put_user(iop_watchdog_timeout(), argp);
173 break;
174 }
175 return ret;
176}
177
178static int iop_wdt_release(struct inode *inode, struct file *file)
179{
180 int state = 1;
181 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
182 if (test_bit(WDT_ENABLED, &wdt_status))
183 state = wdt_disable();
184
185 /* if the timer is not disabled reload and notify that we are still
186 * going down
187 */
188 if (state != 0) {
189 wdt_enable();
190 pr_crit("Device closed unexpectedly - reset in %lu seconds\n",
191 iop_watchdog_timeout());
192 }
193
194 clear_bit(WDT_IN_USE, &wdt_status);
195 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
196
197 return 0;
198}
199
200static const struct file_operations iop_wdt_fops = {
201 .owner = THIS_MODULE,
202 .llseek = no_llseek,
203 .write = iop_wdt_write,
204 .unlocked_ioctl = iop_wdt_ioctl,
205 .compat_ioctl = compat_ptr_ioctl,
206 .open = iop_wdt_open,
207 .release = iop_wdt_release,
208};
209
210static struct miscdevice iop_wdt_miscdev = {
211 .minor = WATCHDOG_MINOR,
212 .name = "watchdog",
213 .fops = &iop_wdt_fops,
214};
215
216static int __init iop_wdt_init(void)
217{
218 int ret;
219
220 /* check if the reset was caused by the watchdog timer */
221 boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0;
222
223 /* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset
224 * NOTE: An IB Reset will Reset both cores in the IOP342
225 */
226 write_wdtsr(IOP13XX_WDTCR_IB_RESET);
227
228 /* Register after we have the device set up so we cannot race
229 with an open */
230 ret = misc_register(&iop_wdt_miscdev);
231 if (ret == 0)
232 pr_info("timeout %lu sec\n", iop_watchdog_timeout());
233
234 return ret;
235}
236
237static void __exit iop_wdt_exit(void)
238{
239 misc_deregister(&iop_wdt_miscdev);
240}
241
242module_init(iop_wdt_init);
243module_exit(iop_wdt_exit);
244
245module_param(nowayout, bool, 0);
246MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
247
248MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>");
249MODULE_DESCRIPTION("iop watchdog timer driver");
250MODULE_LICENSE("GPL");