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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Intel 21285 watchdog driver
4 * Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998
5 *
6 * based on
7 *
8 * SoftDog 0.05: A Software Watchdog Device
9 *
10 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
11 * All Rights Reserved.
12 */
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/types.h>
19#include <linux/kernel.h>
20#include <linux/fs.h>
21#include <linux/mm.h>
22#include <linux/miscdevice.h>
23#include <linux/watchdog.h>
24#include <linux/reboot.h>
25#include <linux/init.h>
26#include <linux/interrupt.h>
27#include <linux/uaccess.h>
28#include <linux/irq.h>
29#include <mach/hardware.h>
30
31#include <asm/mach-types.h>
32#include <asm/system_info.h>
33#include <asm/hardware/dec21285.h>
34
35/*
36 * Define this to stop the watchdog actually rebooting the machine.
37 */
38#undef ONLY_TESTING
39
40static unsigned int soft_margin = 60; /* in seconds */
41static unsigned int reload;
42static unsigned long timer_alive;
43
44#ifdef ONLY_TESTING
45/*
46 * If the timer expires..
47 */
48static void watchdog_fire(int irq, void *dev_id)
49{
50 pr_crit("Would Reboot\n");
51 *CSR_TIMER4_CNTL = 0;
52 *CSR_TIMER4_CLR = 0;
53}
54#endif
55
56/*
57 * Refresh the timer.
58 */
59static void watchdog_ping(void)
60{
61 *CSR_TIMER4_LOAD = reload;
62}
63
64/*
65 * Allow only one person to hold it open
66 */
67static int watchdog_open(struct inode *inode, struct file *file)
68{
69 int ret;
70
71 if (*CSR_SA110_CNTL & (1 << 13))
72 return -EBUSY;
73
74 if (test_and_set_bit(1, &timer_alive))
75 return -EBUSY;
76
77 reload = soft_margin * (mem_fclk_21285 / 256);
78
79 *CSR_TIMER4_CLR = 0;
80 watchdog_ping();
81 *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
82 | TIMER_CNTL_DIV256;
83
84#ifdef ONLY_TESTING
85 ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
86 if (ret) {
87 *CSR_TIMER4_CNTL = 0;
88 clear_bit(1, &timer_alive);
89 }
90#else
91 /*
92 * Setting this bit is irreversible; once enabled, there is
93 * no way to disable the watchdog.
94 */
95 *CSR_SA110_CNTL |= 1 << 13;
96
97 ret = 0;
98#endif
99 stream_open(inode, file);
100 return ret;
101}
102
103/*
104 * Shut off the timer.
105 * Note: if we really have enabled the watchdog, there
106 * is no way to turn off.
107 */
108static int watchdog_release(struct inode *inode, struct file *file)
109{
110#ifdef ONLY_TESTING
111 free_irq(IRQ_TIMER4, NULL);
112 clear_bit(1, &timer_alive);
113#endif
114 return 0;
115}
116
117static ssize_t watchdog_write(struct file *file, const char __user *data,
118 size_t len, loff_t *ppos)
119{
120 /*
121 * Refresh the timer.
122 */
123 if (len)
124 watchdog_ping();
125
126 return len;
127}
128
129static const struct watchdog_info ident = {
130 .options = WDIOF_SETTIMEOUT,
131 .identity = "Footbridge Watchdog",
132};
133
134static long watchdog_ioctl(struct file *file, unsigned int cmd,
135 unsigned long arg)
136{
137 int __user *int_arg = (int __user *)arg;
138 int new_margin, ret = -ENOTTY;
139
140 switch (cmd) {
141 case WDIOC_GETSUPPORT:
142 ret = 0;
143 if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
144 ret = -EFAULT;
145 break;
146
147 case WDIOC_GETSTATUS:
148 case WDIOC_GETBOOTSTATUS:
149 ret = put_user(0, int_arg);
150 break;
151
152 case WDIOC_KEEPALIVE:
153 watchdog_ping();
154 ret = 0;
155 break;
156
157 case WDIOC_SETTIMEOUT:
158 ret = get_user(new_margin, int_arg);
159 if (ret)
160 break;
161
162 /* Arbitrary, can't find the card's limits */
163 if (new_margin < 0 || new_margin > 60) {
164 ret = -EINVAL;
165 break;
166 }
167
168 soft_margin = new_margin;
169 reload = soft_margin * (mem_fclk_21285 / 256);
170 watchdog_ping();
171 fallthrough;
172 case WDIOC_GETTIMEOUT:
173 ret = put_user(soft_margin, int_arg);
174 break;
175 }
176 return ret;
177}
178
179static const struct file_operations watchdog_fops = {
180 .owner = THIS_MODULE,
181 .write = watchdog_write,
182 .unlocked_ioctl = watchdog_ioctl,
183 .compat_ioctl = compat_ptr_ioctl,
184 .open = watchdog_open,
185 .release = watchdog_release,
186};
187
188static struct miscdevice watchdog_miscdev = {
189 .minor = WATCHDOG_MINOR,
190 .name = "watchdog",
191 .fops = &watchdog_fops,
192};
193
194static int __init footbridge_watchdog_init(void)
195{
196 int retval;
197
198 if (machine_is_netwinder())
199 return -ENODEV;
200
201 retval = misc_register(&watchdog_miscdev);
202 if (retval < 0)
203 return retval;
204
205 pr_info("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
206 soft_margin);
207
208 return 0;
209}
210
211static void __exit footbridge_watchdog_exit(void)
212{
213 misc_deregister(&watchdog_miscdev);
214}
215
216MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
217MODULE_DESCRIPTION("Footbridge watchdog driver");
218MODULE_LICENSE("GPL");
219
220module_param(soft_margin, int, 0);
221MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
222
223module_init(footbridge_watchdog_init);
224module_exit(footbridge_watchdog_exit);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Intel 21285 watchdog driver
4 * Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998
5 *
6 * based on
7 *
8 * SoftDog 0.05: A Software Watchdog Device
9 *
10 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
11 * All Rights Reserved.
12 */
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/types.h>
19#include <linux/kernel.h>
20#include <linux/fs.h>
21#include <linux/mm.h>
22#include <linux/miscdevice.h>
23#include <linux/watchdog.h>
24#include <linux/reboot.h>
25#include <linux/init.h>
26#include <linux/interrupt.h>
27#include <linux/uaccess.h>
28#include <linux/irq.h>
29#include <mach/hardware.h>
30
31#include <asm/mach-types.h>
32#include <asm/system_info.h>
33#include <asm/hardware/dec21285.h>
34
35/*
36 * Define this to stop the watchdog actually rebooting the machine.
37 */
38#undef ONLY_TESTING
39
40static unsigned int soft_margin = 60; /* in seconds */
41static unsigned int reload;
42static unsigned long timer_alive;
43
44#ifdef ONLY_TESTING
45/*
46 * If the timer expires..
47 */
48static void watchdog_fire(int irq, void *dev_id)
49{
50 pr_crit("Would Reboot\n");
51 *CSR_TIMER4_CNTL = 0;
52 *CSR_TIMER4_CLR = 0;
53}
54#endif
55
56/*
57 * Refresh the timer.
58 */
59static void watchdog_ping(void)
60{
61 *CSR_TIMER4_LOAD = reload;
62}
63
64/*
65 * Allow only one person to hold it open
66 */
67static int watchdog_open(struct inode *inode, struct file *file)
68{
69 int ret;
70
71 if (*CSR_SA110_CNTL & (1 << 13))
72 return -EBUSY;
73
74 if (test_and_set_bit(1, &timer_alive))
75 return -EBUSY;
76
77 reload = soft_margin * (mem_fclk_21285 / 256);
78
79 *CSR_TIMER4_CLR = 0;
80 watchdog_ping();
81 *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
82 | TIMER_CNTL_DIV256;
83
84#ifdef ONLY_TESTING
85 ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
86 if (ret) {
87 *CSR_TIMER4_CNTL = 0;
88 clear_bit(1, &timer_alive);
89 }
90#else
91 /*
92 * Setting this bit is irreversible; once enabled, there is
93 * no way to disable the watchdog.
94 */
95 *CSR_SA110_CNTL |= 1 << 13;
96
97 ret = 0;
98#endif
99 stream_open(inode, file);
100 return ret;
101}
102
103/*
104 * Shut off the timer.
105 * Note: if we really have enabled the watchdog, there
106 * is no way to turn off.
107 */
108static int watchdog_release(struct inode *inode, struct file *file)
109{
110#ifdef ONLY_TESTING
111 free_irq(IRQ_TIMER4, NULL);
112 clear_bit(1, &timer_alive);
113#endif
114 return 0;
115}
116
117static ssize_t watchdog_write(struct file *file, const char __user *data,
118 size_t len, loff_t *ppos)
119{
120 /*
121 * Refresh the timer.
122 */
123 if (len)
124 watchdog_ping();
125
126 return len;
127}
128
129static const struct watchdog_info ident = {
130 .options = WDIOF_SETTIMEOUT,
131 .identity = "Footbridge Watchdog",
132};
133
134static long watchdog_ioctl(struct file *file, unsigned int cmd,
135 unsigned long arg)
136{
137 int __user *int_arg = (int __user *)arg;
138 int new_margin, ret = -ENOTTY;
139
140 switch (cmd) {
141 case WDIOC_GETSUPPORT:
142 ret = 0;
143 if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
144 ret = -EFAULT;
145 break;
146
147 case WDIOC_GETSTATUS:
148 case WDIOC_GETBOOTSTATUS:
149 ret = put_user(0, int_arg);
150 break;
151
152 case WDIOC_KEEPALIVE:
153 watchdog_ping();
154 ret = 0;
155 break;
156
157 case WDIOC_SETTIMEOUT:
158 ret = get_user(new_margin, int_arg);
159 if (ret)
160 break;
161
162 /* Arbitrary, can't find the card's limits */
163 if (new_margin < 0 || new_margin > 60) {
164 ret = -EINVAL;
165 break;
166 }
167
168 soft_margin = new_margin;
169 reload = soft_margin * (mem_fclk_21285 / 256);
170 watchdog_ping();
171 fallthrough;
172 case WDIOC_GETTIMEOUT:
173 ret = put_user(soft_margin, int_arg);
174 break;
175 }
176 return ret;
177}
178
179static const struct file_operations watchdog_fops = {
180 .owner = THIS_MODULE,
181 .llseek = no_llseek,
182 .write = watchdog_write,
183 .unlocked_ioctl = watchdog_ioctl,
184 .compat_ioctl = compat_ptr_ioctl,
185 .open = watchdog_open,
186 .release = watchdog_release,
187};
188
189static struct miscdevice watchdog_miscdev = {
190 .minor = WATCHDOG_MINOR,
191 .name = "watchdog",
192 .fops = &watchdog_fops,
193};
194
195static int __init footbridge_watchdog_init(void)
196{
197 int retval;
198
199 if (machine_is_netwinder())
200 return -ENODEV;
201
202 retval = misc_register(&watchdog_miscdev);
203 if (retval < 0)
204 return retval;
205
206 pr_info("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
207 soft_margin);
208
209 if (machine_is_cats())
210 pr_warn("Warning: Watchdog reset may not work on this machine\n");
211 return 0;
212}
213
214static void __exit footbridge_watchdog_exit(void)
215{
216 misc_deregister(&watchdog_miscdev);
217}
218
219MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
220MODULE_DESCRIPTION("Footbridge watchdog driver");
221MODULE_LICENSE("GPL");
222
223module_param(soft_margin, int, 0);
224MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
225
226module_init(footbridge_watchdog_init);
227module_exit(footbridge_watchdog_exit);