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a9cb3959 HCE |
1 | /* |
2 | * Watchdog driver for Atmel AT32AP700X devices | |
3 | * | |
4 | * Copyright (C) 2005-2006 Atmel Corporation | |
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 | ||
11 | #include <linux/init.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/moduleparam.h> | |
15 | #include <linux/miscdevice.h> | |
16 | #include <linux/fs.h> | |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/watchdog.h> | |
19 | ||
20 | #include <asm/uaccess.h> | |
21 | #include <asm/io.h> | |
22 | ||
23 | #define TIMEOUT_MIN 1 | |
24 | #define TIMEOUT_DEFAULT CONFIG_AT32AP700X_WDT_TIMEOUT | |
25 | #define TIMEOUT_MAX 2 | |
26 | ||
27 | /* Watchdog registers and write/read macro */ | |
28 | #define WDT_CTRL 0x00 | |
29 | #define WDT_CTRL_EN 0 | |
30 | #define WDT_CTRL_PSEL 8 | |
31 | #define WDT_CTRL_KEY 24 | |
32 | ||
33 | #define WDT_CLR 0x04 | |
34 | ||
35 | #define WDT_BIT(name) (1 << WDT_##name) | |
36 | #define WDT_BF(name,value) ((value) << WDT_##name) | |
37 | ||
38 | #define wdt_readl(dev,reg) \ | |
39 | __raw_readl((dev)->regs + WDT_##reg) | |
40 | #define wdt_writel(dev,reg,value) \ | |
41 | __raw_writel((value), (dev)->regs + WDT_##reg) | |
42 | ||
43 | struct wdt_at32ap700x { | |
44 | void __iomem *regs; | |
45 | int timeout; | |
46 | int users; | |
47 | struct miscdevice miscdev; | |
48 | }; | |
49 | ||
50 | static struct wdt_at32ap700x *wdt; | |
51 | ||
52 | /* | |
53 | * Disable the watchdog. | |
54 | */ | |
55 | static void inline at32_wdt_stop(void) | |
56 | { | |
57 | unsigned long psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f); | |
58 | wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55)); | |
59 | wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa)); | |
60 | } | |
61 | ||
62 | /* | |
63 | * Enable and reset the watchdog. | |
64 | */ | |
65 | static void inline at32_wdt_start(void) | |
66 | { | |
67 | /* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */ | |
68 | unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe; | |
69 | ||
70 | wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN) | |
71 | | WDT_BF(CTRL_PSEL, psel) | |
72 | | WDT_BF(CTRL_KEY, 0x55)); | |
73 | wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN) | |
74 | | WDT_BF(CTRL_PSEL, psel) | |
75 | | WDT_BF(CTRL_KEY, 0xaa)); | |
76 | } | |
77 | ||
78 | /* | |
79 | * Pat the watchdog timer. | |
80 | */ | |
81 | static void inline at32_wdt_pat(void) | |
82 | { | |
83 | wdt_writel(wdt, CLR, 0x42); | |
84 | } | |
85 | ||
86 | /* | |
87 | * Watchdog device is opened, and watchdog starts running. | |
88 | */ | |
89 | static int at32_wdt_open(struct inode *inode, struct file *file) | |
90 | { | |
91 | if (test_and_set_bit(1, &wdt->users)) | |
92 | return -EBUSY; | |
93 | ||
94 | at32_wdt_start(); | |
95 | return nonseekable_open(inode, file); | |
96 | } | |
97 | ||
98 | /* | |
99 | * Close the watchdog device. If CONFIG_WATCHDOG_NOWAYOUT is _not_ defined then | |
100 | * the watchdog is also disabled. | |
101 | */ | |
102 | static int at32_wdt_close(struct inode *inode, struct file *file) | |
103 | { | |
104 | #ifndef CONFIG_WATCHDOG_NOWAYOUT | |
105 | at32_wdt_stop(); | |
106 | #endif | |
107 | clear_bit(1, &wdt->users); | |
108 | return 0; | |
109 | } | |
110 | ||
111 | /* | |
112 | * Change the watchdog time interval. | |
113 | */ | |
114 | static int at32_wdt_settimeout(int time) | |
115 | { | |
116 | /* | |
117 | * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is | |
118 | * 2 ^ 16 allowing up to 2 seconds timeout. | |
119 | */ | |
120 | if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX)) | |
121 | return -EINVAL; | |
122 | ||
123 | /* Set new watchdog time. It will be used when at32_wdt_start() is called. */ | |
124 | wdt->timeout = time; | |
125 | return 0; | |
126 | } | |
127 | ||
128 | static struct watchdog_info at32_wdt_info = { | |
129 | .identity = "at32ap700x watchdog", | |
130 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
131 | }; | |
132 | ||
133 | /* | |
134 | * Handle commands from user-space. | |
135 | */ | |
136 | static int at32_wdt_ioctl(struct inode *inode, struct file *file, | |
137 | unsigned int cmd, unsigned long arg) | |
138 | { | |
139 | int ret = -ENOTTY; | |
140 | int time; | |
141 | void __user *argp = (void __user *)arg; | |
142 | int __user *p = argp; | |
143 | ||
144 | switch(cmd) { | |
145 | case WDIOC_KEEPALIVE: | |
146 | at32_wdt_pat(); | |
147 | ret = 0; | |
148 | break; | |
149 | case WDIOC_GETSUPPORT: | |
150 | ret = copy_to_user(argp, &at32_wdt_info, | |
151 | sizeof(at32_wdt_info)) ? -EFAULT : 0; | |
152 | break; | |
153 | case WDIOC_SETTIMEOUT: | |
154 | ret = get_user(time, p); | |
155 | if (ret) | |
156 | break; | |
157 | ret = at32_wdt_settimeout(time); | |
158 | if (ret) | |
159 | break; | |
160 | /* Enable new time value */ | |
161 | at32_wdt_start(); | |
162 | /* fall through */ | |
163 | case WDIOC_GETTIMEOUT: | |
164 | ret = put_user(wdt->timeout, p); | |
165 | break; | |
166 | case WDIOC_GETSTATUS: /* fall through */ | |
167 | case WDIOC_GETBOOTSTATUS: | |
168 | ret = put_user(0, p); | |
169 | break; | |
170 | case WDIOC_SETOPTIONS: | |
171 | ret = get_user(time, p); | |
172 | if (ret) | |
173 | break; | |
174 | if (time & WDIOS_DISABLECARD) | |
175 | at32_wdt_stop(); | |
176 | if (time & WDIOS_ENABLECARD) | |
177 | at32_wdt_start(); | |
178 | ret = 0; | |
179 | break; | |
180 | } | |
181 | ||
182 | return ret; | |
183 | } | |
184 | ||
185 | static ssize_t at32_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) | |
186 | { | |
187 | at32_wdt_pat(); | |
188 | return len; | |
189 | } | |
190 | ||
191 | static const struct file_operations at32_wdt_fops = { | |
192 | .owner = THIS_MODULE, | |
193 | .llseek = no_llseek, | |
194 | .ioctl = at32_wdt_ioctl, | |
195 | .open = at32_wdt_open, | |
196 | .release = at32_wdt_close, | |
197 | .write = at32_wdt_write, | |
198 | }; | |
199 | ||
200 | static int __init at32_wdt_probe(struct platform_device *pdev) | |
201 | { | |
202 | struct resource *regs; | |
203 | int ret; | |
204 | ||
205 | if (wdt) { | |
206 | dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n"); | |
207 | return -EBUSY; | |
208 | } | |
209 | ||
210 | regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
211 | if (!regs) { | |
212 | dev_dbg(&pdev->dev, "missing mmio resource\n"); | |
213 | return -ENXIO; | |
214 | } | |
215 | ||
216 | wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL); | |
217 | if (!wdt) { | |
218 | dev_dbg(&pdev->dev, "no memory for wdt structure\n"); | |
219 | return -ENOMEM; | |
220 | } | |
221 | ||
222 | wdt->regs = ioremap(regs->start, regs->end - regs->start + 1); | |
223 | wdt->users = 0; | |
224 | wdt->miscdev.minor = WATCHDOG_MINOR; | |
225 | wdt->miscdev.name = "watchdog"; | |
226 | wdt->miscdev.fops = &at32_wdt_fops; | |
227 | ||
228 | if (at32_wdt_settimeout(TIMEOUT_DEFAULT)) { | |
229 | at32_wdt_settimeout(TIMEOUT_MAX); | |
230 | dev_dbg(&pdev->dev, | |
231 | "default timeout invalid, set to %d sec.\n", | |
232 | TIMEOUT_MAX); | |
233 | } | |
234 | ||
235 | ret = misc_register(&wdt->miscdev); | |
236 | if (ret) { | |
237 | dev_dbg(&pdev->dev, "failed to register wdt miscdev\n"); | |
238 | goto err_register; | |
239 | } | |
240 | ||
241 | platform_set_drvdata(pdev, wdt); | |
242 | wdt->miscdev.parent = &pdev->dev; | |
243 | dev_info(&pdev->dev, "AT32AP700X WDT at 0x%p\n", wdt->regs); | |
244 | ||
245 | return 0; | |
246 | ||
247 | err_register: | |
248 | kfree(wdt); | |
249 | wdt = NULL; | |
250 | return ret; | |
251 | } | |
252 | ||
253 | static int __exit at32_wdt_remove(struct platform_device *pdev) | |
254 | { | |
255 | if (wdt && platform_get_drvdata(pdev) == wdt) { | |
256 | misc_deregister(&wdt->miscdev); | |
257 | kfree(wdt); | |
258 | wdt = NULL; | |
259 | platform_set_drvdata(pdev, NULL); | |
260 | } | |
261 | ||
262 | return 0; | |
263 | } | |
264 | ||
265 | static void at32_wdt_shutdown(struct platform_device *pdev) | |
266 | { | |
267 | at32_wdt_stop(); | |
268 | } | |
269 | ||
270 | #ifdef CONFIG_PM | |
271 | static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
272 | { | |
273 | at32_wdt_stop(); | |
274 | return 0; | |
275 | } | |
276 | ||
277 | static int at32_wdt_resume(struct platform_device *pdev) | |
278 | { | |
279 | if (wdt->users) | |
280 | at32_wdt_start(); | |
281 | return 0; | |
282 | } | |
283 | #endif | |
284 | ||
285 | static struct platform_driver at32_wdt_driver = { | |
286 | .remove = __exit_p(at32_wdt_remove), | |
287 | #ifdef CONFIG_PM | |
288 | .suspend = at32_wdt_suspend, | |
289 | .resume = at32_wdt_resume, | |
290 | #endif | |
291 | .driver = { | |
292 | .name = "at32_wdt", | |
293 | .owner = THIS_MODULE, | |
294 | }, | |
295 | .shutdown = at32_wdt_shutdown, | |
296 | }; | |
297 | ||
298 | static int __init at32_wdt_init(void) | |
299 | { | |
300 | return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe); | |
301 | } | |
302 | module_init(at32_wdt_init); | |
303 | ||
304 | static void __exit at32_wdt_exit(void) | |
305 | { | |
306 | platform_driver_unregister(&at32_wdt_driver); | |
307 | } | |
308 | module_exit(at32_wdt_exit); | |
309 | ||
310 | MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>"); | |
311 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X"); | |
312 | MODULE_LICENSE("GPL"); | |
313 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |