1 /*
2 * Watchdog timer for PowerPC Book-E systems
3 *
4 * Author: Matthew McClintock
5 * Maintainer: Kumar Gala <galak@kernel.crashing.org>
6 *
7 * Copyright 2005, 2008 Freescale Semiconductor Inc.
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the
11 * Free Software Foundation; either version 2 of the License, or (at your
12 * option) any later version.
13 */
14
15 #include <linux/module.h>
16 #include <linux/fs.h>
17 #include <linux/smp.h>
18 #include <linux/miscdevice.h>
19 #include <linux/notifier.h>
20 #include <linux/watchdog.h>
21 #include <linux/uaccess.h>
22
23 #include <asm/reg_booke.h>
24 #include <asm/system.h>
25
26 /* If the kernel parameter wdt=1, the watchdog will be enabled at boot.
27 * Also, the wdt_period sets the watchdog timer period timeout.
28 * For E500 cpus the wdt_period sets which bit changing from 0->1 will
29 * trigger a watchog timeout. This watchdog timeout will occur 3 times, the
30 * first time nothing will happen, the second time a watchdog exception will
31 * occur, and the final time the board will reset.
32 */
33
34 #ifdef CONFIG_FSL_BOOKE
35 #define WDT_PERIOD_DEFAULT 63 /* Ex. wdt_period=28 bus=333Mhz,reset=~40sec */
36 #else
37 #define WDT_PERIOD_DEFAULT 3 /* Refer to the PPC40x and PPC4xx manuals */
38 #endif /* for timing information */
39
40 u32 booke_wdt_enabled;
41 u32 booke_wdt_period = WDT_PERIOD_DEFAULT;
42
43 #ifdef CONFIG_FSL_BOOKE
44 #define WDTP(x) ((((63-x)&0x3)<<30)|(((63-x)&0x3c)<<15))
45 #define WDTP_MASK (WDTP(0))
46 #else
47 #define WDTP(x) (TCR_WP(x))
48 #define WDTP_MASK (TCR_WP_MASK)
49 #endif
50
51 static DEFINE_SPINLOCK(booke_wdt_lock);
52
__booke_wdt_ping(void * data)53 static void __booke_wdt_ping(void *data)
54 {
55 mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
56 }
57
booke_wdt_ping(void)58 static void booke_wdt_ping(void)
59 {
60 on_each_cpu(__booke_wdt_ping, NULL, 0);
61 }
62
__booke_wdt_enable(void * data)63 static void __booke_wdt_enable(void *data)
64 {
65 u32 val;
66
67 /* clear status before enabling watchdog */
68 __booke_wdt_ping(NULL);
69 val = mfspr(SPRN_TCR);
70 val &= ~WDTP_MASK;
71 val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
72
73 mtspr(SPRN_TCR, val);
74 }
75
booke_wdt_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)76 static ssize_t booke_wdt_write(struct file *file, const char __user *buf,
77 size_t count, loff_t *ppos)
78 {
79 booke_wdt_ping();
80 return count;
81 }
82
83 static struct watchdog_info ident = {
84 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
85 .identity = "PowerPC Book-E Watchdog",
86 };
87
booke_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)88 static long booke_wdt_ioctl(struct file *file,
89 unsigned int cmd, unsigned long arg)
90 {
91 u32 tmp = 0;
92 u32 __user *p = (u32 __user *)arg;
93
94 switch (cmd) {
95 case WDIOC_GETSUPPORT:
96 if (copy_to_user(arg, &ident, sizeof(struct watchdog_info)))
97 return -EFAULT;
98 case WDIOC_GETSTATUS:
99 return put_user(ident.options, p);
100 case WDIOC_GETBOOTSTATUS:
101 /* XXX: something is clearing TSR */
102 tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
103 /* returns 1 if last reset was caused by the WDT */
104 return (tmp ? 1 : 0);
105 case WDIOC_SETOPTIONS:
106 if (get_user(tmp, p))
107 return -EINVAL;
108 if (tmp == WDIOS_ENABLECARD) {
109 booke_wdt_ping();
110 break;
111 } else
112 return -EINVAL;
113 return 0;
114 case WDIOC_KEEPALIVE:
115 booke_wdt_ping();
116 return 0;
117 case WDIOC_SETTIMEOUT:
118 if (get_user(booke_wdt_period, p))
119 return -EFAULT;
120 mtspr(SPRN_TCR, (mfspr(SPRN_TCR) & ~WDTP_MASK) |
121 WDTP(booke_wdt_period));
122 return 0;
123 case WDIOC_GETTIMEOUT:
124 return put_user(booke_wdt_period, p);
125 default:
126 return -ENOTTY;
127 }
128
129 return 0;
130 }
131
booke_wdt_open(struct inode * inode,struct file * file)132 static int booke_wdt_open(struct inode *inode, struct file *file)
133 {
134 spin_lock(&booke_wdt_lock);
135 if (booke_wdt_enabled == 0) {
136 booke_wdt_enabled = 1;
137 on_each_cpu(__booke_wdt_enable, NULL, 0);
138 printk(KERN_INFO
139 "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
140 booke_wdt_period);
141 }
142 spin_unlock(&booke_wdt_lock);
143
144 return nonseekable_open(inode, file);
145 }
146
147 static const struct file_operations booke_wdt_fops = {
148 .owner = THIS_MODULE,
149 .llseek = no_llseek,
150 .write = booke_wdt_write,
151 .unlocked_ioctl = booke_wdt_ioctl,
152 .open = booke_wdt_open,
153 };
154
155 static struct miscdevice booke_wdt_miscdev = {
156 .minor = WATCHDOG_MINOR,
157 .name = "watchdog",
158 .fops = &booke_wdt_fops,
159 };
160
booke_wdt_exit(void)161 static void __exit booke_wdt_exit(void)
162 {
163 misc_deregister(&booke_wdt_miscdev);
164 }
165
booke_wdt_init(void)166 static int __init booke_wdt_init(void)
167 {
168 int ret = 0;
169
170 printk(KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n");
171 ident.firmware_version = cur_cpu_spec->pvr_value;
172
173 ret = misc_register(&booke_wdt_miscdev);
174 if (ret) {
175 printk(KERN_CRIT "Cannot register miscdev on minor=%d: %d\n",
176 WATCHDOG_MINOR, ret);
177 return ret;
178 }
179
180 spin_lock(&booke_wdt_lock);
181 if (booke_wdt_enabled == 1) {
182 printk(KERN_INFO
183 "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
184 booke_wdt_period);
185 on_each_cpu(__booke_wdt_enable, NULL, 0);
186 }
187 spin_unlock(&booke_wdt_lock);
188
189 return ret;
190 }
191 device_initcall(booke_wdt_init);
192