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7768a13c KS |
1 | /* |
2 | * linux/drivers/char/watchdog/omap_wdt.c | |
3 | * | |
4 | * Watchdog driver for the TI OMAP 16xx & 24xx 32KHz (non-secure) watchdog | |
5 | * | |
6 | * Author: MontaVista Software, Inc. | |
7 | * <gdavis@mvista.com> or <source@mvista.com> | |
8 | * | |
9 | * 2003 (c) MontaVista Software, Inc. This file is licensed under the | |
10 | * terms of the GNU General Public License version 2. This program is | |
11 | * licensed "as is" without any warranty of any kind, whether express | |
12 | * or implied. | |
13 | * | |
14 | * History: | |
15 | * | |
16 | * 20030527: George G. Davis <gdavis@mvista.com> | |
17 | * Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c | |
18 | * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> | |
19 | * Based on SoftDog driver by Alan Cox <alan@redhat.com> | |
20 | * | |
21 | * Copyright (c) 2004 Texas Instruments. | |
22 | * 1. Modified to support OMAP1610 32-KHz watchdog timer | |
23 | * 2. Ported to 2.6 kernel | |
24 | * | |
25 | * Copyright (c) 2005 David Brownell | |
26 | * Use the driver model and standard identifiers; handle bigger timeouts. | |
27 | */ | |
28 | ||
29 | #include <linux/module.h> | |
7768a13c KS |
30 | #include <linux/types.h> |
31 | #include <linux/kernel.h> | |
32 | #include <linux/fs.h> | |
33 | #include <linux/mm.h> | |
34 | #include <linux/miscdevice.h> | |
35 | #include <linux/watchdog.h> | |
36 | #include <linux/reboot.h> | |
7768a13c KS |
37 | #include <linux/init.h> |
38 | #include <linux/err.h> | |
39 | #include <linux/platform_device.h> | |
40 | #include <linux/moduleparam.h> | |
41 | #include <linux/clk.h> | |
1977f032 | 42 | #include <linux/bitops.h> |
7768a13c KS |
43 | |
44 | #include <asm/io.h> | |
45 | #include <asm/uaccess.h> | |
46 | #include <asm/hardware.h> | |
7768a13c KS |
47 | |
48 | #include <asm/arch/prcm.h> | |
49 | ||
50 | #include "omap_wdt.h" | |
51 | ||
52 | static unsigned timer_margin; | |
53 | module_param(timer_margin, uint, 0); | |
54 | MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)"); | |
55 | ||
56 | static int omap_wdt_users; | |
57 | static struct clk *armwdt_ck = NULL; | |
58 | static struct clk *mpu_wdt_ick = NULL; | |
59 | static struct clk *mpu_wdt_fck = NULL; | |
60 | ||
61 | static unsigned int wdt_trgr_pattern = 0x1234; | |
62 | ||
63 | static void omap_wdt_ping(void) | |
64 | { | |
65 | /* wait for posted write to complete */ | |
66 | while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08) | |
67 | cpu_relax(); | |
68 | wdt_trgr_pattern = ~wdt_trgr_pattern; | |
69 | omap_writel(wdt_trgr_pattern, (OMAP_WATCHDOG_TGR)); | |
70 | /* wait for posted write to complete */ | |
71 | while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08) | |
72 | cpu_relax(); | |
73 | /* reloaded WCRR from WLDR */ | |
74 | } | |
75 | ||
76 | static void omap_wdt_enable(void) | |
77 | { | |
78 | /* Sequence to enable the watchdog */ | |
79 | omap_writel(0xBBBB, OMAP_WATCHDOG_SPR); | |
80 | while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10) | |
81 | cpu_relax(); | |
82 | omap_writel(0x4444, OMAP_WATCHDOG_SPR); | |
83 | while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10) | |
84 | cpu_relax(); | |
85 | } | |
86 | ||
87 | static void omap_wdt_disable(void) | |
88 | { | |
89 | /* sequence required to disable watchdog */ | |
90 | omap_writel(0xAAAA, OMAP_WATCHDOG_SPR); /* TIMER_MODE */ | |
91 | while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10) | |
92 | cpu_relax(); | |
93 | omap_writel(0x5555, OMAP_WATCHDOG_SPR); /* TIMER_MODE */ | |
94 | while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10) | |
95 | cpu_relax(); | |
96 | } | |
97 | ||
98 | static void omap_wdt_adjust_timeout(unsigned new_timeout) | |
99 | { | |
100 | if (new_timeout < TIMER_MARGIN_MIN) | |
101 | new_timeout = TIMER_MARGIN_DEFAULT; | |
102 | if (new_timeout > TIMER_MARGIN_MAX) | |
103 | new_timeout = TIMER_MARGIN_MAX; | |
104 | timer_margin = new_timeout; | |
105 | } | |
106 | ||
107 | static void omap_wdt_set_timeout(void) | |
108 | { | |
109 | u32 pre_margin = GET_WLDR_VAL(timer_margin); | |
110 | ||
111 | /* just count up at 32 KHz */ | |
112 | while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04) | |
113 | cpu_relax(); | |
114 | omap_writel(pre_margin, OMAP_WATCHDOG_LDR); | |
115 | while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04) | |
116 | cpu_relax(); | |
117 | } | |
118 | ||
119 | /* | |
120 | * Allow only one task to hold it open | |
121 | */ | |
122 | ||
123 | static int omap_wdt_open(struct inode *inode, struct file *file) | |
124 | { | |
125 | if (test_and_set_bit(1, (unsigned long *)&omap_wdt_users)) | |
126 | return -EBUSY; | |
127 | ||
128 | if (cpu_is_omap16xx()) | |
129 | clk_enable(armwdt_ck); /* Enable the clock */ | |
130 | ||
131 | if (cpu_is_omap24xx()) { | |
132 | clk_enable(mpu_wdt_ick); /* Enable the interface clock */ | |
133 | clk_enable(mpu_wdt_fck); /* Enable the functional clock */ | |
134 | } | |
135 | ||
136 | /* initialize prescaler */ | |
137 | while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01) | |
138 | cpu_relax(); | |
139 | omap_writel((1 << 5) | (PTV << 2), OMAP_WATCHDOG_CNTRL); | |
140 | while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01) | |
141 | cpu_relax(); | |
142 | ||
143 | omap_wdt_set_timeout(); | |
144 | omap_wdt_enable(); | |
ec9505a7 | 145 | return nonseekable_open(inode, file); |
7768a13c KS |
146 | } |
147 | ||
148 | static int omap_wdt_release(struct inode *inode, struct file *file) | |
149 | { | |
150 | /* | |
151 | * Shut off the timer unless NOWAYOUT is defined. | |
152 | */ | |
153 | #ifndef CONFIG_WATCHDOG_NOWAYOUT | |
154 | omap_wdt_disable(); | |
155 | ||
156 | if (cpu_is_omap16xx()) { | |
157 | clk_disable(armwdt_ck); /* Disable the clock */ | |
158 | clk_put(armwdt_ck); | |
159 | armwdt_ck = NULL; | |
160 | } | |
161 | ||
162 | if (cpu_is_omap24xx()) { | |
163 | clk_disable(mpu_wdt_ick); /* Disable the clock */ | |
164 | clk_disable(mpu_wdt_fck); /* Disable the clock */ | |
165 | clk_put(mpu_wdt_ick); | |
166 | clk_put(mpu_wdt_fck); | |
167 | mpu_wdt_ick = NULL; | |
168 | mpu_wdt_fck = NULL; | |
169 | } | |
170 | #else | |
171 | printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n"); | |
172 | #endif | |
173 | omap_wdt_users = 0; | |
174 | return 0; | |
175 | } | |
176 | ||
177 | static ssize_t | |
178 | omap_wdt_write(struct file *file, const char __user *data, | |
179 | size_t len, loff_t *ppos) | |
180 | { | |
181 | /* Refresh LOAD_TIME. */ | |
182 | if (len) | |
183 | omap_wdt_ping(); | |
184 | return len; | |
185 | } | |
186 | ||
187 | static int | |
188 | omap_wdt_ioctl(struct inode *inode, struct file *file, | |
189 | unsigned int cmd, unsigned long arg) | |
190 | { | |
191 | int new_margin; | |
192 | static struct watchdog_info ident = { | |
193 | .identity = "OMAP Watchdog", | |
194 | .options = WDIOF_SETTIMEOUT, | |
195 | .firmware_version = 0, | |
196 | }; | |
197 | ||
198 | switch (cmd) { | |
199 | default: | |
1bf1496d | 200 | return -ENOTTY; |
7768a13c KS |
201 | case WDIOC_GETSUPPORT: |
202 | return copy_to_user((struct watchdog_info __user *)arg, &ident, | |
203 | sizeof(ident)); | |
204 | case WDIOC_GETSTATUS: | |
205 | return put_user(0, (int __user *)arg); | |
206 | case WDIOC_GETBOOTSTATUS: | |
207 | if (cpu_is_omap16xx()) | |
208 | return put_user(omap_readw(ARM_SYSST), | |
209 | (int __user *)arg); | |
210 | if (cpu_is_omap24xx()) | |
211 | return put_user(omap_prcm_get_reset_sources(), | |
212 | (int __user *)arg); | |
213 | case WDIOC_KEEPALIVE: | |
214 | omap_wdt_ping(); | |
215 | return 0; | |
216 | case WDIOC_SETTIMEOUT: | |
217 | if (get_user(new_margin, (int __user *)arg)) | |
218 | return -EFAULT; | |
219 | omap_wdt_adjust_timeout(new_margin); | |
220 | ||
221 | omap_wdt_disable(); | |
222 | omap_wdt_set_timeout(); | |
223 | omap_wdt_enable(); | |
224 | ||
225 | omap_wdt_ping(); | |
226 | /* Fall */ | |
227 | case WDIOC_GETTIMEOUT: | |
228 | return put_user(timer_margin, (int __user *)arg); | |
229 | } | |
230 | } | |
231 | ||
2b8693c0 | 232 | static const struct file_operations omap_wdt_fops = { |
7768a13c KS |
233 | .owner = THIS_MODULE, |
234 | .write = omap_wdt_write, | |
235 | .ioctl = omap_wdt_ioctl, | |
236 | .open = omap_wdt_open, | |
237 | .release = omap_wdt_release, | |
238 | }; | |
239 | ||
240 | static struct miscdevice omap_wdt_miscdev = { | |
241 | .minor = WATCHDOG_MINOR, | |
242 | .name = "watchdog", | |
243 | .fops = &omap_wdt_fops | |
244 | }; | |
245 | ||
246 | static int __init omap_wdt_probe(struct platform_device *pdev) | |
247 | { | |
248 | struct resource *res, *mem; | |
249 | int ret; | |
250 | ||
251 | /* reserve static register mappings */ | |
252 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
253 | if (!res) | |
254 | return -ENOENT; | |
255 | ||
256 | mem = request_mem_region(res->start, res->end - res->start + 1, | |
257 | pdev->name); | |
258 | if (mem == NULL) | |
259 | return -EBUSY; | |
260 | ||
261 | platform_set_drvdata(pdev, mem); | |
262 | ||
263 | omap_wdt_users = 0; | |
264 | ||
265 | if (cpu_is_omap16xx()) { | |
266 | armwdt_ck = clk_get(&pdev->dev, "armwdt_ck"); | |
267 | if (IS_ERR(armwdt_ck)) { | |
268 | ret = PTR_ERR(armwdt_ck); | |
269 | armwdt_ck = NULL; | |
270 | goto fail; | |
271 | } | |
272 | } | |
273 | ||
274 | if (cpu_is_omap24xx()) { | |
275 | mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick"); | |
276 | if (IS_ERR(mpu_wdt_ick)) { | |
277 | ret = PTR_ERR(mpu_wdt_ick); | |
278 | mpu_wdt_ick = NULL; | |
279 | goto fail; | |
280 | } | |
281 | mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck"); | |
282 | if (IS_ERR(mpu_wdt_fck)) { | |
283 | ret = PTR_ERR(mpu_wdt_fck); | |
284 | mpu_wdt_fck = NULL; | |
285 | goto fail; | |
286 | } | |
287 | } | |
288 | ||
289 | omap_wdt_disable(); | |
290 | omap_wdt_adjust_timeout(timer_margin); | |
291 | ||
e0b79e0b | 292 | omap_wdt_miscdev.parent = &pdev->dev; |
7768a13c KS |
293 | ret = misc_register(&omap_wdt_miscdev); |
294 | if (ret) | |
295 | goto fail; | |
296 | ||
297 | pr_info("OMAP Watchdog Timer: initial timeout %d sec\n", timer_margin); | |
298 | ||
299 | /* autogate OCP interface clock */ | |
300 | omap_writel(0x01, OMAP_WATCHDOG_SYS_CONFIG); | |
301 | return 0; | |
302 | ||
303 | fail: | |
304 | if (armwdt_ck) | |
305 | clk_put(armwdt_ck); | |
306 | if (mpu_wdt_ick) | |
307 | clk_put(mpu_wdt_ick); | |
308 | if (mpu_wdt_fck) | |
309 | clk_put(mpu_wdt_fck); | |
310 | release_resource(mem); | |
311 | return ret; | |
312 | } | |
313 | ||
314 | static void omap_wdt_shutdown(struct platform_device *pdev) | |
315 | { | |
316 | omap_wdt_disable(); | |
317 | } | |
318 | ||
319 | static int omap_wdt_remove(struct platform_device *pdev) | |
320 | { | |
321 | struct resource *mem = platform_get_drvdata(pdev); | |
322 | misc_deregister(&omap_wdt_miscdev); | |
323 | release_resource(mem); | |
324 | if (armwdt_ck) | |
325 | clk_put(armwdt_ck); | |
326 | if (mpu_wdt_ick) | |
327 | clk_put(mpu_wdt_ick); | |
328 | if (mpu_wdt_fck) | |
329 | clk_put(mpu_wdt_fck); | |
330 | return 0; | |
331 | } | |
332 | ||
333 | #ifdef CONFIG_PM | |
334 | ||
335 | /* REVISIT ... not clear this is the best way to handle system suspend; and | |
336 | * it's very inappropriate for selective device suspend (e.g. suspending this | |
337 | * through sysfs rather than by stopping the watchdog daemon). Also, this | |
338 | * may not play well enough with NOWAYOUT... | |
339 | */ | |
340 | ||
341 | static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state) | |
342 | { | |
343 | if (omap_wdt_users) | |
344 | omap_wdt_disable(); | |
345 | return 0; | |
346 | } | |
347 | ||
348 | static int omap_wdt_resume(struct platform_device *pdev) | |
349 | { | |
350 | if (omap_wdt_users) { | |
351 | omap_wdt_enable(); | |
352 | omap_wdt_ping(); | |
353 | } | |
354 | return 0; | |
355 | } | |
356 | ||
357 | #else | |
358 | #define omap_wdt_suspend NULL | |
359 | #define omap_wdt_resume NULL | |
360 | #endif | |
361 | ||
362 | static struct platform_driver omap_wdt_driver = { | |
363 | .probe = omap_wdt_probe, | |
364 | .remove = omap_wdt_remove, | |
365 | .shutdown = omap_wdt_shutdown, | |
366 | .suspend = omap_wdt_suspend, | |
367 | .resume = omap_wdt_resume, | |
368 | .driver = { | |
369 | .owner = THIS_MODULE, | |
370 | .name = "omap_wdt", | |
371 | }, | |
372 | }; | |
373 | ||
374 | static int __init omap_wdt_init(void) | |
375 | { | |
376 | return platform_driver_register(&omap_wdt_driver); | |
377 | } | |
378 | ||
379 | static void __exit omap_wdt_exit(void) | |
380 | { | |
381 | platform_driver_unregister(&omap_wdt_driver); | |
382 | } | |
383 | ||
384 | module_init(omap_wdt_init); | |
385 | module_exit(omap_wdt_exit); | |
386 | ||
387 | MODULE_AUTHOR("George G. Davis"); | |
388 | MODULE_LICENSE("GPL"); | |
389 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
f37d193c | 390 | MODULE_ALIAS("platform:omap_wdt"); |