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6f702fce AN |
1 | /* |
2 | * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs | |
3 | * | |
4 | * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | */ | |
10 | #include <linux/module.h> | |
11 | #include <linux/moduleparam.h> | |
12 | #include <linux/types.h> | |
13 | #include <linux/miscdevice.h> | |
14 | #include <linux/watchdog.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/reboot.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/uaccess.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/clk.h> | |
21 | #include <linux/err.h> | |
22 | #include <linux/io.h> | |
23 | #include <asm/txx9tmr.h> | |
24 | ||
25 | #define TIMER_MARGIN 60 /* Default is 60 seconds */ | |
26 | ||
27 | static int timeout = TIMER_MARGIN; /* in seconds */ | |
28 | module_param(timeout, int, 0); | |
29 | MODULE_PARM_DESC(timeout, | |
30 | "Watchdog timeout in seconds. " | |
31 | "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), " | |
32 | "default=" __MODULE_STRING(TIMER_MARGIN) ")"); | |
33 | ||
34 | static int nowayout = WATCHDOG_NOWAYOUT; | |
35 | module_param(nowayout, int, 0); | |
36 | MODULE_PARM_DESC(nowayout, | |
37 | "Watchdog cannot be stopped once started " | |
38 | "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
39 | ||
40 | #define WD_TIMER_CCD 7 /* 1/256 */ | |
41 | #define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD)) | |
42 | #define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK) | |
43 | ||
44 | static unsigned long txx9wdt_alive; | |
45 | static int expect_close; | |
46 | static struct txx9_tmr_reg __iomem *txx9wdt_reg; | |
47 | static struct clk *txx9_imclk; | |
f8494e06 | 48 | static DEFINE_SPINLOCK(txx9_lock); |
6f702fce AN |
49 | |
50 | static void txx9wdt_ping(void) | |
51 | { | |
8dc244f7 | 52 | spin_lock(&txx9_lock); |
6f702fce | 53 | __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); |
8dc244f7 | 54 | spin_unlock(&txx9_lock); |
6f702fce AN |
55 | } |
56 | ||
57 | static void txx9wdt_start(void) | |
58 | { | |
8dc244f7 | 59 | spin_lock(&txx9_lock); |
6f702fce AN |
60 | __raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra); |
61 | __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr); | |
62 | __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */ | |
63 | __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG, | |
64 | &txx9wdt_reg->tcr); | |
65 | __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); | |
8dc244f7 | 66 | spin_unlock(&txx9_lock); |
6f702fce AN |
67 | } |
68 | ||
69 | static void txx9wdt_stop(void) | |
70 | { | |
8dc244f7 | 71 | spin_lock(&txx9_lock); |
6f702fce AN |
72 | __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr); |
73 | __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE, | |
74 | &txx9wdt_reg->tcr); | |
8dc244f7 | 75 | spin_unlock(&txx9_lock); |
6f702fce AN |
76 | } |
77 | ||
78 | static int txx9wdt_open(struct inode *inode, struct file *file) | |
79 | { | |
80 | if (test_and_set_bit(0, &txx9wdt_alive)) | |
81 | return -EBUSY; | |
82 | ||
83 | if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) { | |
84 | clear_bit(0, &txx9wdt_alive); | |
85 | return -EBUSY; | |
86 | } | |
87 | ||
88 | if (nowayout) | |
89 | __module_get(THIS_MODULE); | |
90 | ||
91 | txx9wdt_start(); | |
92 | return nonseekable_open(inode, file); | |
93 | } | |
94 | ||
95 | static int txx9wdt_release(struct inode *inode, struct file *file) | |
96 | { | |
97 | if (expect_close) | |
98 | txx9wdt_stop(); | |
99 | else { | |
100 | printk(KERN_CRIT "txx9wdt: " | |
101 | "Unexpected close, not stopping watchdog!\n"); | |
102 | txx9wdt_ping(); | |
103 | } | |
104 | clear_bit(0, &txx9wdt_alive); | |
105 | expect_close = 0; | |
106 | return 0; | |
107 | } | |
108 | ||
109 | static ssize_t txx9wdt_write(struct file *file, const char __user *data, | |
110 | size_t len, loff_t *ppos) | |
111 | { | |
112 | if (len) { | |
113 | if (!nowayout) { | |
114 | size_t i; | |
115 | ||
116 | expect_close = 0; | |
117 | for (i = 0; i != len; i++) { | |
118 | char c; | |
119 | if (get_user(c, data + i)) | |
120 | return -EFAULT; | |
121 | if (c == 'V') | |
122 | expect_close = 1; | |
123 | } | |
124 | } | |
125 | txx9wdt_ping(); | |
126 | } | |
127 | return len; | |
128 | } | |
129 | ||
8dc244f7 AC |
130 | static long txx9wdt_ioctl(struct file *file, unsigned int cmd, |
131 | unsigned long arg) | |
6f702fce AN |
132 | { |
133 | void __user *argp = (void __user *)arg; | |
134 | int __user *p = argp; | |
135 | int new_timeout; | |
8dc244f7 | 136 | static const struct watchdog_info ident = { |
6f702fce AN |
137 | .options = WDIOF_SETTIMEOUT | |
138 | WDIOF_KEEPALIVEPING | | |
139 | WDIOF_MAGICCLOSE, | |
140 | .firmware_version = 0, | |
141 | .identity = "Hardware Watchdog for TXx9", | |
142 | }; | |
143 | ||
144 | switch (cmd) { | |
6f702fce AN |
145 | case WDIOC_GETSUPPORT: |
146 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
147 | case WDIOC_GETSTATUS: | |
148 | case WDIOC_GETBOOTSTATUS: | |
149 | return put_user(0, p); | |
150 | case WDIOC_KEEPALIVE: | |
151 | txx9wdt_ping(); | |
152 | return 0; | |
153 | case WDIOC_SETTIMEOUT: | |
154 | if (get_user(new_timeout, p)) | |
155 | return -EFAULT; | |
156 | if (new_timeout < 1 || new_timeout > WD_MAX_TIMEOUT) | |
157 | return -EINVAL; | |
158 | timeout = new_timeout; | |
159 | txx9wdt_stop(); | |
160 | txx9wdt_start(); | |
161 | /* Fall */ | |
162 | case WDIOC_GETTIMEOUT: | |
163 | return put_user(timeout, p); | |
0c06090c WVS |
164 | default: |
165 | return -ENOTTY; | |
6f702fce AN |
166 | } |
167 | } | |
168 | ||
169 | static int txx9wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
170 | void *unused) | |
171 | { | |
172 | if (code == SYS_DOWN || code == SYS_HALT) | |
173 | txx9wdt_stop(); | |
174 | return NOTIFY_DONE; | |
175 | } | |
176 | ||
177 | static const struct file_operations txx9wdt_fops = { | |
8dc244f7 AC |
178 | .owner = THIS_MODULE, |
179 | .llseek = no_llseek, | |
180 | .write = txx9wdt_write, | |
181 | .unlocked_ioctl = txx9wdt_ioctl, | |
182 | .open = txx9wdt_open, | |
183 | .release = txx9wdt_release, | |
6f702fce AN |
184 | }; |
185 | ||
186 | static struct miscdevice txx9wdt_miscdev = { | |
8dc244f7 AC |
187 | .minor = WATCHDOG_MINOR, |
188 | .name = "watchdog", | |
189 | .fops = &txx9wdt_fops, | |
6f702fce AN |
190 | }; |
191 | ||
192 | static struct notifier_block txx9wdt_notifier = { | |
7944d3a5 | 193 | .notifier_call = txx9wdt_notify_sys, |
6f702fce AN |
194 | }; |
195 | ||
196 | static int __init txx9wdt_probe(struct platform_device *dev) | |
197 | { | |
198 | struct resource *res; | |
199 | int ret; | |
200 | ||
201 | txx9_imclk = clk_get(NULL, "imbus_clk"); | |
202 | if (IS_ERR(txx9_imclk)) { | |
203 | ret = PTR_ERR(txx9_imclk); | |
204 | txx9_imclk = NULL; | |
205 | goto exit; | |
206 | } | |
207 | ret = clk_enable(txx9_imclk); | |
208 | if (ret) { | |
209 | clk_put(txx9_imclk); | |
210 | txx9_imclk = NULL; | |
211 | goto exit; | |
212 | } | |
213 | ||
214 | res = platform_get_resource(dev, IORESOURCE_MEM, 0); | |
215 | if (!res) | |
216 | goto exit_busy; | |
217 | if (!devm_request_mem_region(&dev->dev, | |
218 | res->start, res->end - res->start + 1, | |
219 | "txx9wdt")) | |
220 | goto exit_busy; | |
221 | txx9wdt_reg = devm_ioremap(&dev->dev, | |
222 | res->start, res->end - res->start + 1); | |
223 | if (!txx9wdt_reg) | |
224 | goto exit_busy; | |
225 | ||
226 | ret = register_reboot_notifier(&txx9wdt_notifier); | |
227 | if (ret) | |
228 | goto exit; | |
229 | ||
230 | ret = misc_register(&txx9wdt_miscdev); | |
231 | if (ret) { | |
232 | unregister_reboot_notifier(&txx9wdt_notifier); | |
233 | goto exit; | |
234 | } | |
235 | ||
236 | printk(KERN_INFO "Hardware Watchdog Timer for TXx9: " | |
237 | "timeout=%d sec (max %ld) (nowayout= %d)\n", | |
238 | timeout, WD_MAX_TIMEOUT, nowayout); | |
239 | ||
240 | return 0; | |
241 | exit_busy: | |
242 | ret = -EBUSY; | |
243 | exit: | |
244 | if (txx9_imclk) { | |
245 | clk_disable(txx9_imclk); | |
246 | clk_put(txx9_imclk); | |
247 | } | |
248 | return ret; | |
249 | } | |
250 | ||
251 | static int __exit txx9wdt_remove(struct platform_device *dev) | |
252 | { | |
253 | misc_deregister(&txx9wdt_miscdev); | |
254 | unregister_reboot_notifier(&txx9wdt_notifier); | |
255 | clk_disable(txx9_imclk); | |
256 | clk_put(txx9_imclk); | |
257 | return 0; | |
258 | } | |
259 | ||
260 | static struct platform_driver txx9wdt_driver = { | |
261 | .remove = __exit_p(txx9wdt_remove), | |
262 | .driver = { | |
263 | .name = "txx9wdt", | |
264 | .owner = THIS_MODULE, | |
265 | }, | |
266 | }; | |
267 | ||
268 | static int __init watchdog_init(void) | |
269 | { | |
270 | return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe); | |
271 | } | |
272 | ||
273 | static void __exit watchdog_exit(void) | |
274 | { | |
275 | platform_driver_unregister(&txx9wdt_driver); | |
276 | } | |
277 | ||
278 | module_init(watchdog_init); | |
279 | module_exit(watchdog_exit); | |
280 | ||
281 | MODULE_DESCRIPTION("TXx9 Watchdog Driver"); | |
282 | MODULE_LICENSE("GPL"); | |
283 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
f37d193c | 284 | MODULE_ALIAS("platform:txx9wdt"); |