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a2f40ccd KG |
1 | /* |
2 | * drivers/char/watchdog/booke_wdt.c | |
3 | * | |
4 | * Watchdog timer for PowerPC Book-E systems | |
5 | * | |
6 | * Author: Matthew McClintock | |
4c8d3d99 | 7 | * Maintainer: Kumar Gala <galak@kernel.crashing.org> |
a2f40ccd KG |
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 | ||
a2f40ccd KG |
17 | #include <linux/module.h> |
18 | #include <linux/fs.h> | |
19 | #include <linux/miscdevice.h> | |
20 | #include <linux/notifier.h> | |
21 | #include <linux/watchdog.h> | |
22 | ||
23 | #include <asm/reg_booke.h> | |
24 | #include <asm/uaccess.h> | |
39cdc4bf | 25 | #include <asm/system.h> |
a2f40ccd | 26 | |
40ebbcbf | 27 | /* If the kernel parameter wdt=1, the watchdog will be enabled at boot. |
a2f40ccd KG |
28 | * Also, the wdt_period sets the watchdog timer period timeout. |
29 | * For E500 cpus the wdt_period sets which bit changing from 0->1 will | |
30 | * trigger a watchog timeout. This watchdog timeout will occur 3 times, the | |
31 | * first time nothing will happen, the second time a watchdog exception will | |
32 | * occur, and the final time the board will reset. | |
33 | */ | |
34 | ||
35 | #ifdef CONFIG_FSL_BOOKE | |
36 | #define WDT_PERIOD_DEFAULT 63 /* Ex. wdt_period=28 bus=333Mhz , reset=~40sec */ | |
37 | #else | |
f31909c0 | 38 | #define WDT_PERIOD_DEFAULT 3 /* Refer to the PPC40x and PPC4xx manuals */ |
a2f40ccd KG |
39 | #endif /* for timing information */ |
40 | ||
39cdc4bf KG |
41 | u32 booke_wdt_enabled = 0; |
42 | u32 booke_wdt_period = WDT_PERIOD_DEFAULT; | |
a2f40ccd KG |
43 | |
44 | #ifdef CONFIG_FSL_BOOKE | |
45 | #define WDTP(x) ((((63-x)&0x3)<<30)|(((63-x)&0x3c)<<15)) | |
46 | #else | |
47 | #define WDTP(x) (TCR_WP(x)) | |
48 | #endif | |
49 | ||
f31909c0 SR |
50 | /* |
51 | * booke_wdt_ping: | |
52 | */ | |
53 | static __inline__ void booke_wdt_ping(void) | |
54 | { | |
55 | mtspr(SPRN_TSR, TSR_ENW|TSR_WIS); | |
56 | } | |
57 | ||
a2f40ccd KG |
58 | /* |
59 | * booke_wdt_enable: | |
60 | */ | |
61 | static __inline__ void booke_wdt_enable(void) | |
62 | { | |
63 | u32 val; | |
64 | ||
f31909c0 SR |
65 | /* clear status before enabling watchdog */ |
66 | booke_wdt_ping(); | |
a2f40ccd | 67 | val = mfspr(SPRN_TCR); |
39cdc4bf | 68 | val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period)); |
a2f40ccd KG |
69 | |
70 | mtspr(SPRN_TCR, val); | |
71 | } | |
72 | ||
a2f40ccd KG |
73 | /* |
74 | * booke_wdt_write: | |
75 | */ | |
538bacf8 | 76 | static ssize_t booke_wdt_write (struct file *file, const char __user *buf, |
a2f40ccd KG |
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 | .firmware_version = 0, | |
86 | .identity = "PowerPC Book-E Watchdog", | |
87 | }; | |
88 | ||
89 | /* | |
90 | * booke_wdt_ioctl: | |
91 | */ | |
92 | static int booke_wdt_ioctl (struct inode *inode, struct file *file, | |
93 | unsigned int cmd, unsigned long arg) | |
94 | { | |
95 | u32 tmp = 0; | |
538bacf8 | 96 | u32 __user *p = (u32 __user *)arg; |
a2f40ccd KG |
97 | |
98 | switch (cmd) { | |
99 | case WDIOC_GETSUPPORT: | |
538bacf8 | 100 | if (copy_to_user ((struct watchdog_info __user *) arg, &ident, |
a2f40ccd KG |
101 | sizeof(struct watchdog_info))) |
102 | return -EFAULT; | |
103 | case WDIOC_GETSTATUS: | |
538bacf8 | 104 | return put_user(ident.options, p); |
a2f40ccd KG |
105 | case WDIOC_GETBOOTSTATUS: |
106 | /* XXX: something is clearing TSR */ | |
107 | tmp = mfspr(SPRN_TSR) & TSR_WRS(3); | |
108 | /* returns 1 if last reset was caused by the WDT */ | |
109 | return (tmp ? 1 : 0); | |
110 | case WDIOC_KEEPALIVE: | |
111 | booke_wdt_ping(); | |
112 | return 0; | |
113 | case WDIOC_SETTIMEOUT: | |
538bacf8 | 114 | if (get_user(booke_wdt_period, p)) |
a2f40ccd | 115 | return -EFAULT; |
39cdc4bf | 116 | mtspr(SPRN_TCR, (mfspr(SPRN_TCR)&~WDTP(0))|WDTP(booke_wdt_period)); |
a2f40ccd KG |
117 | return 0; |
118 | case WDIOC_GETTIMEOUT: | |
538bacf8 | 119 | return put_user(booke_wdt_period, p); |
a2f40ccd | 120 | case WDIOC_SETOPTIONS: |
538bacf8 | 121 | if (get_user(tmp, p)) |
a2f40ccd KG |
122 | return -EINVAL; |
123 | if (tmp == WDIOS_ENABLECARD) { | |
124 | booke_wdt_ping(); | |
125 | break; | |
126 | } else | |
127 | return -EINVAL; | |
128 | return 0; | |
129 | default: | |
795b89d2 | 130 | return -ENOTTY; |
a2f40ccd KG |
131 | } |
132 | ||
133 | return 0; | |
134 | } | |
135 | /* | |
136 | * booke_wdt_open: | |
137 | */ | |
138 | static int booke_wdt_open (struct inode *inode, struct file *file) | |
139 | { | |
39cdc4bf KG |
140 | if (booke_wdt_enabled == 0) { |
141 | booke_wdt_enabled = 1; | |
a2f40ccd KG |
142 | booke_wdt_enable(); |
143 | printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n", | |
39cdc4bf | 144 | booke_wdt_period); |
a2f40ccd KG |
145 | } |
146 | ||
ec9505a7 | 147 | return nonseekable_open(inode, file); |
a2f40ccd KG |
148 | } |
149 | ||
62322d25 | 150 | static const struct file_operations booke_wdt_fops = { |
a2f40ccd KG |
151 | .owner = THIS_MODULE, |
152 | .llseek = no_llseek, | |
153 | .write = booke_wdt_write, | |
154 | .ioctl = booke_wdt_ioctl, | |
155 | .open = booke_wdt_open, | |
156 | }; | |
157 | ||
158 | static struct miscdevice booke_wdt_miscdev = { | |
159 | .minor = WATCHDOG_MINOR, | |
160 | .name = "watchdog", | |
161 | .fops = &booke_wdt_fops, | |
162 | }; | |
163 | ||
164 | static void __exit booke_wdt_exit(void) | |
165 | { | |
166 | misc_deregister(&booke_wdt_miscdev); | |
167 | } | |
168 | ||
169 | /* | |
170 | * booke_wdt_init: | |
171 | */ | |
172 | static int __init booke_wdt_init(void) | |
173 | { | |
174 | int ret = 0; | |
175 | ||
176 | printk (KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n"); | |
a78719c3 | 177 | ident.firmware_version = cur_cpu_spec->pvr_value; |
a2f40ccd KG |
178 | |
179 | ret = misc_register(&booke_wdt_miscdev); | |
180 | if (ret) { | |
181 | printk (KERN_CRIT "Cannot register miscdev on minor=%d (err=%d)\n", | |
182 | WATCHDOG_MINOR, ret); | |
183 | return ret; | |
184 | } | |
185 | ||
39cdc4bf | 186 | if (booke_wdt_enabled == 1) { |
a2f40ccd | 187 | printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n", |
39cdc4bf | 188 | booke_wdt_period); |
a2f40ccd KG |
189 | booke_wdt_enable(); |
190 | } | |
191 | ||
192 | return ret; | |
193 | } | |
194 | device_initcall(booke_wdt_init); |