Commit | Line | Data |
---|---|---|
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; | |
48 | ||
49 | static void txx9wdt_ping(void) | |
50 | { | |
51 | __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); | |
52 | } | |
53 | ||
54 | static void txx9wdt_start(void) | |
55 | { | |
56 | __raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra); | |
57 | __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr); | |
58 | __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */ | |
59 | __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG, | |
60 | &txx9wdt_reg->tcr); | |
61 | __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); | |
62 | } | |
63 | ||
64 | static void txx9wdt_stop(void) | |
65 | { | |
66 | __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr); | |
67 | __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE, | |
68 | &txx9wdt_reg->tcr); | |
69 | } | |
70 | ||
71 | static int txx9wdt_open(struct inode *inode, struct file *file) | |
72 | { | |
73 | if (test_and_set_bit(0, &txx9wdt_alive)) | |
74 | return -EBUSY; | |
75 | ||
76 | if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) { | |
77 | clear_bit(0, &txx9wdt_alive); | |
78 | return -EBUSY; | |
79 | } | |
80 | ||
81 | if (nowayout) | |
82 | __module_get(THIS_MODULE); | |
83 | ||
84 | txx9wdt_start(); | |
85 | return nonseekable_open(inode, file); | |
86 | } | |
87 | ||
88 | static int txx9wdt_release(struct inode *inode, struct file *file) | |
89 | { | |
90 | if (expect_close) | |
91 | txx9wdt_stop(); | |
92 | else { | |
93 | printk(KERN_CRIT "txx9wdt: " | |
94 | "Unexpected close, not stopping watchdog!\n"); | |
95 | txx9wdt_ping(); | |
96 | } | |
97 | clear_bit(0, &txx9wdt_alive); | |
98 | expect_close = 0; | |
99 | return 0; | |
100 | } | |
101 | ||
102 | static ssize_t txx9wdt_write(struct file *file, const char __user *data, | |
103 | size_t len, loff_t *ppos) | |
104 | { | |
105 | if (len) { | |
106 | if (!nowayout) { | |
107 | size_t i; | |
108 | ||
109 | expect_close = 0; | |
110 | for (i = 0; i != len; i++) { | |
111 | char c; | |
112 | if (get_user(c, data + i)) | |
113 | return -EFAULT; | |
114 | if (c == 'V') | |
115 | expect_close = 1; | |
116 | } | |
117 | } | |
118 | txx9wdt_ping(); | |
119 | } | |
120 | return len; | |
121 | } | |
122 | ||
123 | static int txx9wdt_ioctl(struct inode *inode, struct file *file, | |
124 | unsigned int cmd, unsigned long arg) | |
125 | { | |
126 | void __user *argp = (void __user *)arg; | |
127 | int __user *p = argp; | |
128 | int new_timeout; | |
129 | static struct watchdog_info ident = { | |
130 | .options = WDIOF_SETTIMEOUT | | |
131 | WDIOF_KEEPALIVEPING | | |
132 | WDIOF_MAGICCLOSE, | |
133 | .firmware_version = 0, | |
134 | .identity = "Hardware Watchdog for TXx9", | |
135 | }; | |
136 | ||
137 | switch (cmd) { | |
138 | default: | |
139 | return -ENOTTY; | |
140 | case WDIOC_GETSUPPORT: | |
141 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
142 | case WDIOC_GETSTATUS: | |
143 | case WDIOC_GETBOOTSTATUS: | |
144 | return put_user(0, p); | |
145 | case WDIOC_KEEPALIVE: | |
146 | txx9wdt_ping(); | |
147 | return 0; | |
148 | case WDIOC_SETTIMEOUT: | |
149 | if (get_user(new_timeout, p)) | |
150 | return -EFAULT; | |
151 | if (new_timeout < 1 || new_timeout > WD_MAX_TIMEOUT) | |
152 | return -EINVAL; | |
153 | timeout = new_timeout; | |
154 | txx9wdt_stop(); | |
155 | txx9wdt_start(); | |
156 | /* Fall */ | |
157 | case WDIOC_GETTIMEOUT: | |
158 | return put_user(timeout, p); | |
159 | } | |
160 | } | |
161 | ||
162 | static int txx9wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
163 | void *unused) | |
164 | { | |
165 | if (code == SYS_DOWN || code == SYS_HALT) | |
166 | txx9wdt_stop(); | |
167 | return NOTIFY_DONE; | |
168 | } | |
169 | ||
170 | static const struct file_operations txx9wdt_fops = { | |
171 | .owner = THIS_MODULE, | |
172 | .llseek = no_llseek, | |
173 | .write = txx9wdt_write, | |
174 | .ioctl = txx9wdt_ioctl, | |
175 | .open = txx9wdt_open, | |
176 | .release = txx9wdt_release, | |
177 | }; | |
178 | ||
179 | static struct miscdevice txx9wdt_miscdev = { | |
180 | .minor = WATCHDOG_MINOR, | |
181 | .name = "watchdog", | |
182 | .fops = &txx9wdt_fops, | |
183 | }; | |
184 | ||
185 | static struct notifier_block txx9wdt_notifier = { | |
186 | .notifier_call = txx9wdt_notify_sys | |
187 | }; | |
188 | ||
189 | static int __init txx9wdt_probe(struct platform_device *dev) | |
190 | { | |
191 | struct resource *res; | |
192 | int ret; | |
193 | ||
194 | txx9_imclk = clk_get(NULL, "imbus_clk"); | |
195 | if (IS_ERR(txx9_imclk)) { | |
196 | ret = PTR_ERR(txx9_imclk); | |
197 | txx9_imclk = NULL; | |
198 | goto exit; | |
199 | } | |
200 | ret = clk_enable(txx9_imclk); | |
201 | if (ret) { | |
202 | clk_put(txx9_imclk); | |
203 | txx9_imclk = NULL; | |
204 | goto exit; | |
205 | } | |
206 | ||
207 | res = platform_get_resource(dev, IORESOURCE_MEM, 0); | |
208 | if (!res) | |
209 | goto exit_busy; | |
210 | if (!devm_request_mem_region(&dev->dev, | |
211 | res->start, res->end - res->start + 1, | |
212 | "txx9wdt")) | |
213 | goto exit_busy; | |
214 | txx9wdt_reg = devm_ioremap(&dev->dev, | |
215 | res->start, res->end - res->start + 1); | |
216 | if (!txx9wdt_reg) | |
217 | goto exit_busy; | |
218 | ||
219 | ret = register_reboot_notifier(&txx9wdt_notifier); | |
220 | if (ret) | |
221 | goto exit; | |
222 | ||
223 | ret = misc_register(&txx9wdt_miscdev); | |
224 | if (ret) { | |
225 | unregister_reboot_notifier(&txx9wdt_notifier); | |
226 | goto exit; | |
227 | } | |
228 | ||
229 | printk(KERN_INFO "Hardware Watchdog Timer for TXx9: " | |
230 | "timeout=%d sec (max %ld) (nowayout= %d)\n", | |
231 | timeout, WD_MAX_TIMEOUT, nowayout); | |
232 | ||
233 | return 0; | |
234 | exit_busy: | |
235 | ret = -EBUSY; | |
236 | exit: | |
237 | if (txx9_imclk) { | |
238 | clk_disable(txx9_imclk); | |
239 | clk_put(txx9_imclk); | |
240 | } | |
241 | return ret; | |
242 | } | |
243 | ||
244 | static int __exit txx9wdt_remove(struct platform_device *dev) | |
245 | { | |
246 | misc_deregister(&txx9wdt_miscdev); | |
247 | unregister_reboot_notifier(&txx9wdt_notifier); | |
248 | clk_disable(txx9_imclk); | |
249 | clk_put(txx9_imclk); | |
250 | return 0; | |
251 | } | |
252 | ||
253 | static struct platform_driver txx9wdt_driver = { | |
254 | .remove = __exit_p(txx9wdt_remove), | |
255 | .driver = { | |
256 | .name = "txx9wdt", | |
257 | .owner = THIS_MODULE, | |
258 | }, | |
259 | }; | |
260 | ||
261 | static int __init watchdog_init(void) | |
262 | { | |
263 | return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe); | |
264 | } | |
265 | ||
266 | static void __exit watchdog_exit(void) | |
267 | { | |
268 | platform_driver_unregister(&txx9wdt_driver); | |
269 | } | |
270 | ||
271 | module_init(watchdog_init); | |
272 | module_exit(watchdog_exit); | |
273 | ||
274 | MODULE_DESCRIPTION("TXx9 Watchdog Driver"); | |
275 | MODULE_LICENSE("GPL"); | |
276 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |