1 /*
2 * drivers/char/watchdog/booke_wdt.c
3 *
4 * Watchdog timer for PowerPC Book-E systems
5 *
6 * Author: Matthew McClintock
7 * Maintainer: Kumar Gala <galak@kernel.crashing.org>
8 *
9 * Copyright 2005 Freescale Semiconductor Inc.
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the
13 * Free Software Foundation; either version 2 of the License, or (at your
14 * option) any later version.
15 */
16
17 #include <linux/config.h>
18 #include <linux/module.h>
19 #include <linux/fs.h>
20 #include <linux/miscdevice.h>
21 #include <linux/notifier.h>
22 #include <linux/watchdog.h>
23
24 #include <asm/reg_booke.h>
25 #include <asm/uaccess.h>
26 #include <asm/system.h>
27
28 /* If the kernel parameter wdt_enable=1, the watchdog will be enabled at boot.
29 * Also, the wdt_period sets the watchdog timer period timeout.
30 * For E500 cpus the wdt_period sets which bit changing from 0->1 will
31 * trigger a watchog timeout. This watchdog timeout will occur 3 times, the
32 * first time nothing will happen, the second time a watchdog exception will
33 * occur, and the final time the board will reset.
34 */
35
36 #ifdef CONFIG_FSL_BOOKE
37 #define WDT_PERIOD_DEFAULT 63 /* Ex. wdt_period=28 bus=333Mhz , reset=~40sec */
38 #else
39 #define WDT_PERIOD_DEFAULT 4 /* Refer to the PPC40x and PPC4xx manuals */
40 #endif /* for timing information */
41
42 u32 booke_wdt_enabled = 0;
43 u32 booke_wdt_period = WDT_PERIOD_DEFAULT;
44
45 #ifdef CONFIG_FSL_BOOKE
46 #define WDTP(x) ((((63-x)&0x3)<<30)|(((63-x)&0x3c)<<15))
47 #else
48 #define WDTP(x) (TCR_WP(x))
49 #endif
50
51 /*
52 * booke_wdt_enable:
53 */
54 static __inline__ void booke_wdt_enable(void)
55 {
56 u32 val;
57
58 val = mfspr(SPRN_TCR);
59 val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
60
61 mtspr(SPRN_TCR, val);
62 }
63
64 /*
65 * booke_wdt_ping:
66 */
67 static __inline__ void booke_wdt_ping(void)
68 {
69 mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
70 }
71
72 /*
73 * booke_wdt_write:
74 */
75 static ssize_t booke_wdt_write (struct file *file, const char __user *buf,
76 size_t count, loff_t *ppos)
77 {
78 booke_wdt_ping();
79 return count;
80 }
81
82 static struct watchdog_info ident = {
83 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
84 .firmware_version = 0,
85 .identity = "PowerPC Book-E Watchdog",
86 };
87
88 /*
89 * booke_wdt_ioctl:
90 */
91 static int booke_wdt_ioctl (struct inode *inode, struct file *file,
92 unsigned int cmd, unsigned long arg)
93 {
94 u32 tmp = 0;
95 u32 __user *p = (u32 __user *)arg;
96
97 switch (cmd) {
98 case WDIOC_GETSUPPORT:
99 if (copy_to_user ((struct watchdog_info __user *) arg, &ident,
100 sizeof(struct watchdog_info)))
101 return -EFAULT;
102 case WDIOC_GETSTATUS:
103 return put_user(ident.options, p);
104 case WDIOC_GETBOOTSTATUS:
105 /* XXX: something is clearing TSR */
106 tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
107 /* returns 1 if last reset was caused by the WDT */
108 return (tmp ? 1 : 0);
109 case WDIOC_KEEPALIVE:
110 booke_wdt_ping();
111 return 0;
112 case WDIOC_SETTIMEOUT:
113 if (get_user(booke_wdt_period, p))
114 return -EFAULT;
115 mtspr(SPRN_TCR, (mfspr(SPRN_TCR)&~WDTP(0))|WDTP(booke_wdt_period));
116 return 0;
117 case WDIOC_GETTIMEOUT:
118 return put_user(booke_wdt_period, p);
119 case WDIOC_SETOPTIONS:
120 if (get_user(tmp, p))
121 return -EINVAL;
122 if (tmp == WDIOS_ENABLECARD) {
123 booke_wdt_ping();
124 break;
125 } else
126 return -EINVAL;
127 return 0;
128 default:
129 return -ENOIOCTLCMD;
130 }
131
132 return 0;
133 }
134 /*
135 * booke_wdt_open:
136 */
137 static int booke_wdt_open (struct inode *inode, struct file *file)
138 {
139 if (booke_wdt_enabled == 0) {
140 booke_wdt_enabled = 1;
141 booke_wdt_enable();
142 printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
143 booke_wdt_period);
144 }
145
146 return 0;
147 }
148
149 static struct file_operations booke_wdt_fops = {
150 .owner = THIS_MODULE,
151 .llseek = no_llseek,
152 .write = booke_wdt_write,
153 .ioctl = booke_wdt_ioctl,
154 .open = booke_wdt_open,
155 };
156
157 static struct miscdevice booke_wdt_miscdev = {
158 .minor = WATCHDOG_MINOR,
159 .name = "watchdog",
160 .fops = &booke_wdt_fops,
161 };
162
163 static void __exit booke_wdt_exit(void)
164 {
165 misc_deregister(&booke_wdt_miscdev);
166 }
167
168 /*
169 * booke_wdt_init:
170 */
171 static int __init booke_wdt_init(void)
172 {
173 int ret = 0;
174
175 printk (KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n");
176 ident.firmware_version = cur_cpu_spec->pvr_value;
177
178 ret = misc_register(&booke_wdt_miscdev);
179 if (ret) {
180 printk (KERN_CRIT "Cannot register miscdev on minor=%d (err=%d)\n",
181 WATCHDOG_MINOR, ret);
182 return ret;
183 }
184
185 if (booke_wdt_enabled == 1) {
186 printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
187 booke_wdt_period);
188 booke_wdt_enable();
189 }
190
191 return ret;
192 }
193 device_initcall(booke_wdt_init);
194
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