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88cce427 | 1 | /* |
9b9c63ff | 2 | * drivers/watchdog/m54xx_wdt.c |
88cce427 | 3 | * |
9b9c63ff | 4 | * Watchdog driver for ColdFire MCF547x & MCF548x processors |
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5 | * Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be> |
6 | * | |
7 | * Adapted from the IXP4xx watchdog driver, which carries these notices: | |
8 | * | |
9 | * Author: Deepak Saxena <dsaxena@plexity.net> | |
10 | * | |
11 | * Copyright 2004 (c) MontaVista, Software, Inc. | |
12 | * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> | |
13 | * | |
14 | * This file is licensed under the terms of the GNU General Public | |
15 | * License version 2. This program is licensed "as is" without any | |
16 | * warranty of any kind, whether express or implied. | |
17 | */ | |
18 | ||
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19 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
20 | ||
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21 | #include <linux/module.h> |
22 | #include <linux/moduleparam.h> | |
23 | #include <linux/types.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/fs.h> | |
26 | #include <linux/miscdevice.h> | |
27 | #include <linux/watchdog.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/bitops.h> | |
30 | #include <linux/ioport.h> | |
31 | #include <linux/uaccess.h> | |
072cb8b6 | 32 | #include <linux/io.h> |
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33 | |
34 | #include <asm/coldfire.h> | |
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35 | #include <asm/m54xxsim.h> |
36 | #include <asm/m54xxgpt.h> | |
88cce427 | 37 | |
86a1e189 | 38 | static bool nowayout = WATCHDOG_NOWAYOUT; |
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39 | static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */ |
40 | static unsigned long wdt_status; | |
41 | ||
42 | #define WDT_IN_USE 0 | |
43 | #define WDT_OK_TO_CLOSE 1 | |
44 | ||
45 | static void wdt_enable(void) | |
46 | { | |
47 | unsigned int gms0; | |
48 | ||
49 | /* preserve GPIO usage, if any */ | |
944c3d81 | 50 | gms0 = __raw_readl(MCF_GPT_GMS0); |
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51 | if (gms0 & MCF_GPT_GMS_TMS_GPIO) |
52 | gms0 &= (MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_GPIO_MASK | |
53 | | MCF_GPT_GMS_OD); | |
54 | else | |
55 | gms0 = MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_OD; | |
944c3d81 | 56 | __raw_writel(gms0, MCF_GPT_GMS0); |
88cce427 | 57 | __raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) | |
944c3d81 | 58 | MCF_GPT_GCIR_CNT(0xffff), MCF_GPT_GCIR0); |
88cce427 | 59 | gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE; |
944c3d81 | 60 | __raw_writel(gms0, MCF_GPT_GMS0); |
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61 | } |
62 | ||
63 | static void wdt_disable(void) | |
64 | { | |
65 | unsigned int gms0; | |
66 | ||
67 | /* disable watchdog */ | |
944c3d81 | 68 | gms0 = __raw_readl(MCF_GPT_GMS0); |
88cce427 | 69 | gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE); |
944c3d81 | 70 | __raw_writel(gms0, MCF_GPT_GMS0); |
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71 | } |
72 | ||
73 | static void wdt_keepalive(void) | |
74 | { | |
75 | unsigned int gms0; | |
76 | ||
944c3d81 | 77 | gms0 = __raw_readl(MCF_GPT_GMS0); |
88cce427 | 78 | gms0 |= MCF_GPT_GMS_OCPW(0xA5); |
944c3d81 | 79 | __raw_writel(gms0, MCF_GPT_GMS0); |
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80 | } |
81 | ||
9b9c63ff | 82 | static int m54xx_wdt_open(struct inode *inode, struct file *file) |
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83 | { |
84 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) | |
85 | return -EBUSY; | |
86 | ||
87 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
88 | wdt_enable(); | |
c5bf68fe | 89 | return stream_open(inode, file); |
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90 | } |
91 | ||
9b9c63ff | 92 | static ssize_t m54xx_wdt_write(struct file *file, const char *data, |
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93 | size_t len, loff_t *ppos) |
94 | { | |
95 | if (len) { | |
96 | if (!nowayout) { | |
97 | size_t i; | |
98 | ||
99 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
100 | ||
101 | for (i = 0; i != len; i++) { | |
102 | char c; | |
103 | ||
104 | if (get_user(c, data + i)) | |
105 | return -EFAULT; | |
106 | if (c == 'V') | |
107 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
108 | } | |
109 | } | |
110 | wdt_keepalive(); | |
111 | } | |
112 | return len; | |
113 | } | |
114 | ||
115 | static const struct watchdog_info ident = { | |
116 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | | |
117 | WDIOF_KEEPALIVEPING, | |
9b9c63ff | 118 | .identity = "Coldfire M54xx Watchdog", |
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119 | }; |
120 | ||
9b9c63ff | 121 | static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd, |
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122 | unsigned long arg) |
123 | { | |
124 | int ret = -ENOTTY; | |
125 | int time; | |
126 | ||
127 | switch (cmd) { | |
128 | case WDIOC_GETSUPPORT: | |
129 | ret = copy_to_user((struct watchdog_info *)arg, &ident, | |
130 | sizeof(ident)) ? -EFAULT : 0; | |
131 | break; | |
132 | ||
133 | case WDIOC_GETSTATUS: | |
134 | ret = put_user(0, (int *)arg); | |
135 | break; | |
136 | ||
137 | case WDIOC_GETBOOTSTATUS: | |
138 | ret = put_user(0, (int *)arg); | |
139 | break; | |
140 | ||
141 | case WDIOC_KEEPALIVE: | |
142 | wdt_keepalive(); | |
143 | ret = 0; | |
144 | break; | |
145 | ||
146 | case WDIOC_SETTIMEOUT: | |
147 | ret = get_user(time, (int *)arg); | |
148 | if (ret) | |
149 | break; | |
150 | ||
151 | if (time <= 0 || time > 30) { | |
152 | ret = -EINVAL; | |
153 | break; | |
154 | } | |
155 | ||
156 | heartbeat = time; | |
157 | wdt_enable(); | |
bd490f82 | 158 | fallthrough; |
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159 | |
160 | case WDIOC_GETTIMEOUT: | |
161 | ret = put_user(heartbeat, (int *)arg); | |
162 | break; | |
163 | } | |
164 | return ret; | |
165 | } | |
166 | ||
9b9c63ff | 167 | static int m54xx_wdt_release(struct inode *inode, struct file *file) |
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168 | { |
169 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) | |
170 | wdt_disable(); | |
171 | else { | |
27c766aa | 172 | pr_crit("Device closed unexpectedly - timer will not stop\n"); |
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173 | wdt_keepalive(); |
174 | } | |
175 | clear_bit(WDT_IN_USE, &wdt_status); | |
176 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
177 | ||
178 | return 0; | |
179 | } | |
180 | ||
181 | ||
9b9c63ff | 182 | static const struct file_operations m54xx_wdt_fops = { |
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183 | .owner = THIS_MODULE, |
184 | .llseek = no_llseek, | |
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185 | .write = m54xx_wdt_write, |
186 | .unlocked_ioctl = m54xx_wdt_ioctl, | |
b6dfb247 | 187 | .compat_ioctl = compat_ptr_ioctl, |
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188 | .open = m54xx_wdt_open, |
189 | .release = m54xx_wdt_release, | |
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190 | }; |
191 | ||
9b9c63ff | 192 | static struct miscdevice m54xx_wdt_miscdev = { |
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193 | .minor = WATCHDOG_MINOR, |
194 | .name = "watchdog", | |
9b9c63ff | 195 | .fops = &m54xx_wdt_fops, |
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196 | }; |
197 | ||
9b9c63ff | 198 | static int __init m54xx_wdt_init(void) |
88cce427 | 199 | { |
944c3d81 | 200 | if (!request_mem_region(MCF_GPT_GCIR0, 4, "Coldfire M54xx Watchdog")) { |
27c766aa | 201 | pr_warn("I/O region busy\n"); |
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202 | return -EBUSY; |
203 | } | |
27c766aa | 204 | pr_info("driver is loaded\n"); |
88cce427 | 205 | |
9b9c63ff | 206 | return misc_register(&m54xx_wdt_miscdev); |
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207 | } |
208 | ||
9b9c63ff | 209 | static void __exit m54xx_wdt_exit(void) |
88cce427 | 210 | { |
9b9c63ff | 211 | misc_deregister(&m54xx_wdt_miscdev); |
944c3d81 | 212 | release_mem_region(MCF_GPT_GCIR0, 4); |
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213 | } |
214 | ||
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215 | module_init(m54xx_wdt_init); |
216 | module_exit(m54xx_wdt_exit); | |
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217 | |
218 | MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>"); | |
9b9c63ff | 219 | MODULE_DESCRIPTION("Coldfire M54xx Watchdog"); |
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220 | |
221 | module_param(heartbeat, int, 0); | |
222 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)"); | |
223 | ||
86a1e189 | 224 | module_param(nowayout, bool, 0); |
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225 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
226 | ||
227 | MODULE_LICENSE("GPL"); |