1 /*
2 * drivers/char/watchdog/ixp4xx_wdt.c
3 *
4 * Watchdog driver for Intel IXP4xx network processors
5 *
6 * Author: Deepak Saxena <dsaxena@plexity.net>
7 *
8 * Copyright 2004 (c) MontaVista, Software, Inc.
9 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
10 *
11 * This file is licensed under the terms of the GNU General Public
12 * License version 2. This program is licensed "as is" without any
13 * warranty of any kind, whether express or implied.
14 */
15
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/types.h>
21 #include <linux/kernel.h>
22 #include <linux/fs.h>
23 #include <linux/miscdevice.h>
24 #include <linux/of.h>
25 #include <linux/watchdog.h>
26 #include <linux/init.h>
27 #include <linux/bitops.h>
28 #include <linux/uaccess.h>
29 #include <mach/hardware.h>
30
31 static bool nowayout = WATCHDOG_NOWAYOUT;
32 static int heartbeat = 60; /* (secs) Default is 1 minute */
33 static unsigned long wdt_status;
34 static unsigned long boot_status;
35 static DEFINE_SPINLOCK(wdt_lock);
36
37 #define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
38
39 #define WDT_IN_USE 0
40 #define WDT_OK_TO_CLOSE 1
41
wdt_enable(void)42 static void wdt_enable(void)
43 {
44 spin_lock(&wdt_lock);
45 *IXP4XX_OSWK = IXP4XX_WDT_KEY;
46 *IXP4XX_OSWE = 0;
47 *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
48 *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
49 *IXP4XX_OSWK = 0;
50 spin_unlock(&wdt_lock);
51 }
52
wdt_disable(void)53 static void wdt_disable(void)
54 {
55 spin_lock(&wdt_lock);
56 *IXP4XX_OSWK = IXP4XX_WDT_KEY;
57 *IXP4XX_OSWE = 0;
58 *IXP4XX_OSWK = 0;
59 spin_unlock(&wdt_lock);
60 }
61
ixp4xx_wdt_open(struct inode * inode,struct file * file)62 static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
63 {
64 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
65 return -EBUSY;
66
67 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
68 wdt_enable();
69 return stream_open(inode, file);
70 }
71
72 static ssize_t
ixp4xx_wdt_write(struct file * file,const char * data,size_t len,loff_t * ppos)73 ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
74 {
75 if (len) {
76 if (!nowayout) {
77 size_t i;
78
79 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
80
81 for (i = 0; i != len; i++) {
82 char c;
83
84 if (get_user(c, data + i))
85 return -EFAULT;
86 if (c == 'V')
87 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
88 }
89 }
90 wdt_enable();
91 }
92 return len;
93 }
94
95 static const struct watchdog_info ident = {
96 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
97 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
98 .identity = "IXP4xx Watchdog",
99 };
100
101
ixp4xx_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)102 static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
103 unsigned long arg)
104 {
105 int ret = -ENOTTY;
106 int time;
107
108 switch (cmd) {
109 case WDIOC_GETSUPPORT:
110 ret = copy_to_user((struct watchdog_info *)arg, &ident,
111 sizeof(ident)) ? -EFAULT : 0;
112 break;
113
114 case WDIOC_GETSTATUS:
115 ret = put_user(0, (int *)arg);
116 break;
117
118 case WDIOC_GETBOOTSTATUS:
119 ret = put_user(boot_status, (int *)arg);
120 break;
121
122 case WDIOC_KEEPALIVE:
123 wdt_enable();
124 ret = 0;
125 break;
126
127 case WDIOC_SETTIMEOUT:
128 ret = get_user(time, (int *)arg);
129 if (ret)
130 break;
131
132 if (time <= 0 || time > 60) {
133 ret = -EINVAL;
134 break;
135 }
136
137 heartbeat = time;
138 wdt_enable();
139 fallthrough;
140
141 case WDIOC_GETTIMEOUT:
142 ret = put_user(heartbeat, (int *)arg);
143 break;
144 }
145 return ret;
146 }
147
ixp4xx_wdt_release(struct inode * inode,struct file * file)148 static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
149 {
150 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
151 wdt_disable();
152 else
153 pr_crit("Device closed unexpectedly - timer will not stop\n");
154 clear_bit(WDT_IN_USE, &wdt_status);
155 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
156
157 return 0;
158 }
159
160
161 static const struct file_operations ixp4xx_wdt_fops = {
162 .owner = THIS_MODULE,
163 .llseek = no_llseek,
164 .write = ixp4xx_wdt_write,
165 .unlocked_ioctl = ixp4xx_wdt_ioctl,
166 .compat_ioctl = compat_ptr_ioctl,
167 .open = ixp4xx_wdt_open,
168 .release = ixp4xx_wdt_release,
169 };
170
171 static struct miscdevice ixp4xx_wdt_miscdev = {
172 .minor = WATCHDOG_MINOR,
173 .name = "watchdog",
174 .fops = &ixp4xx_wdt_fops,
175 };
176
ixp4xx_wdt_init(void)177 static int __init ixp4xx_wdt_init(void)
178 {
179 int ret;
180
181 /*
182 * FIXME: we bail out on device tree boot but this really needs
183 * to be fixed in a nicer way: this registers the MDIO bus before
184 * even matching the driver infrastructure, we should only probe
185 * detected hardware.
186 */
187 if (of_have_populated_dt())
188 return -ENODEV;
189 if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
190 pr_err("Rev. A0 IXP42x CPU detected - watchdog disabled\n");
191
192 return -ENODEV;
193 }
194 boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
195 WDIOF_CARDRESET : 0;
196 ret = misc_register(&ixp4xx_wdt_miscdev);
197 if (ret == 0)
198 pr_info("timer heartbeat %d sec\n", heartbeat);
199 return ret;
200 }
201
ixp4xx_wdt_exit(void)202 static void __exit ixp4xx_wdt_exit(void)
203 {
204 misc_deregister(&ixp4xx_wdt_miscdev);
205 }
206
207
208 module_init(ixp4xx_wdt_init);
209 module_exit(ixp4xx_wdt_exit);
210
211 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
212 MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
213
214 module_param(heartbeat, int, 0);
215 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
216
217 module_param(nowayout, bool, 0);
218 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
219
220 MODULE_LICENSE("GPL");
221