summaryrefslogtreecommitdiffstats
path: root/drivers/char/watchdog/omap_wdt.c
blob: 8f90b90a502132ffc0ac2e9396c6adb0b865b014 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
/*
 * linux/drivers/char/watchdog/omap_wdt.c
 *
 * Watchdog driver for the TI OMAP 16xx & 24xx 32KHz (non-secure) watchdog
 *
 * Author: MontaVista Software, Inc.
 *	 <gdavis@mvista.com> or <source@mvista.com>
 *
 * 2003 (c) MontaVista Software, Inc. This file is licensed under the
 * terms of the GNU General Public License version 2. This program is
 * licensed "as is" without any warranty of any kind, whether express
 * or implied.
 *
 * History:
 *
 * 20030527: George G. Davis <gdavis@mvista.com>
 *	Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
 *	(c) Copyright 2000 Oleg Drokin <green@crimea.edu>
 *	Based on SoftDog driver by Alan Cox <alan@redhat.com>
 *
 * Copyright (c) 2004 Texas Instruments.
 *	1. Modified to support OMAP1610 32-KHz watchdog timer
 *	2. Ported to 2.6 kernel
 *
 * Copyright (c) 2005 David Brownell
 *	Use the driver model and standard identifiers; handle bigger timeouts.
 */

#include <linux/module.h>
#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/moduleparam.h>
#include <linux/clk.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
#include <asm/bitops.h>

#include <asm/arch/prcm.h>

#include "omap_wdt.h"

static unsigned timer_margin;
module_param(timer_margin, uint, 0);
MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");

static int omap_wdt_users;
static struct clk *armwdt_ck = NULL;
static struct clk *mpu_wdt_ick = NULL;
static struct clk *mpu_wdt_fck = NULL;

static unsigned int wdt_trgr_pattern = 0x1234;

static void omap_wdt_ping(void)
{
	/* wait for posted write to complete */
	while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
		cpu_relax();
	wdt_trgr_pattern = ~wdt_trgr_pattern;
	omap_writel(wdt_trgr_pattern, (OMAP_WATCHDOG_TGR));
	/* wait for posted write to complete */
	while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
		cpu_relax();
	/* reloaded WCRR from WLDR */
}

static void omap_wdt_enable(void)
{
	/* Sequence to enable the watchdog */
	omap_writel(0xBBBB, OMAP_WATCHDOG_SPR);
	while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
		cpu_relax();
	omap_writel(0x4444, OMAP_WATCHDOG_SPR);
	while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
		cpu_relax();
}

static void omap_wdt_disable(void)
{
	/* sequence required to disable watchdog */
	omap_writel(0xAAAA, OMAP_WATCHDOG_SPR);	/* TIMER_MODE */
	while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
		cpu_relax();
	omap_writel(0x5555, OMAP_WATCHDOG_SPR);	/* TIMER_MODE */
	while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
		cpu_relax();
}

static void omap_wdt_adjust_timeout(unsigned new_timeout)
{
	if (new_timeout < TIMER_MARGIN_MIN)
		new_timeout = TIMER_MARGIN_DEFAULT;
	if (new_timeout > TIMER_MARGIN_MAX)
		new_timeout = TIMER_MARGIN_MAX;
	timer_margin = new_timeout;
}

static void omap_wdt_set_timeout(void)
{
	u32 pre_margin = GET_WLDR_VAL(timer_margin);

	/* just count up at 32 KHz */
	while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
		cpu_relax();
	omap_writel(pre_margin, OMAP_WATCHDOG_LDR);
	while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
		cpu_relax();
}

/*
 *	Allow only one task to hold it open
 */

static int omap_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(1, (unsigned long *)&omap_wdt_users))
		return -EBUSY;

	if (cpu_is_omap16xx())
		clk_enable(armwdt_ck);	/* Enable the clock */

	if (cpu_is_omap24xx()) {
		clk_enable(mpu_wdt_ick);    /* Enable the interface clock */
		clk_enable(mpu_wdt_fck);    /* Enable the functional clock */
	}

	/* initialize prescaler */
	while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
		cpu_relax();
	omap_writel((1 << 5) | (PTV << 2), OMAP_WATCHDOG_CNTRL);
	while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
		cpu_relax();

	omap_wdt_set_timeout();
	omap_wdt_enable();
	return 0;
}

static int omap_wdt_release(struct inode *inode, struct file *file)
{
	/*
	 *      Shut off the timer unless NOWAYOUT is defined.
	 */
#ifndef CONFIG_WATCHDOG_NOWAYOUT
	omap_wdt_disable();

	if (cpu_is_omap16xx()) {
		clk_disable(armwdt_ck);	/* Disable the clock */
		clk_put(armwdt_ck);
		armwdt_ck = NULL;
	}

	if (cpu_is_omap24xx()) {
		clk_disable(mpu_wdt_ick);	/* Disable the clock */
		clk_disable(mpu_wdt_fck);	/* Disable the clock */
		clk_put(mpu_wdt_ick);
		clk_put(mpu_wdt_fck);
		mpu_wdt_ick = NULL;
		mpu_wdt_fck = NULL;
	}
#else
	printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
#endif
	omap_wdt_users = 0;
	return 0;
}

static ssize_t
omap_wdt_write(struct file *file, const char __user *data,
		size_t len, loff_t *ppos)
{
	/* Refresh LOAD_TIME. */
	if (len)
		omap_wdt_ping();
	return len;
}

static int
omap_wdt_ioctl(struct inode *inode, struct file *file,
	unsigned int cmd, unsigned long arg)
{
	int new_margin;
	static struct watchdog_info ident = {
		.identity = "OMAP Watchdog",
		.options = WDIOF_SETTIMEOUT,
		.firmware_version = 0,
	};

	switch (cmd) {
	default:
		return -ENOIOCTLCMD;
	case WDIOC_GETSUPPORT:
		return copy_to_user((struct watchdog_info __user *)arg, &ident,
				sizeof(ident));
	case WDIOC_GETSTATUS:
		return put_user(0, (int __user *)arg);
	case WDIOC_GETBOOTSTATUS:
		if (cpu_is_omap16xx())
			return put_user(omap_readw(ARM_SYSST),
					(int __user *)arg);
		if (cpu_is_omap24xx())
			return put_user(omap_prcm_get_reset_sources(),
					(int __user *)arg);
	case WDIOC_KEEPALIVE:
		omap_wdt_ping();
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_margin, (int __user *)arg))
			return -EFAULT;
		omap_wdt_adjust_timeout(new_margin);

		omap_wdt_disable();
		omap_wdt_set_timeout();
		omap_wdt_enable();

		omap_wdt_ping();
		/* Fall */
	case WDIOC_GETTIMEOUT:
		return put_user(timer_margin, (int __user *)arg);
	}
}

static struct file_operations omap_wdt_fops = {
	.owner = THIS_MODULE,
	.write = omap_wdt_write,
	.ioctl = omap_wdt_ioctl,
	.open = omap_wdt_open,
	.release = omap_wdt_release,
};

static struct miscdevice omap_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &omap_wdt_fops
};

static int __init omap_wdt_probe(struct platform_device *pdev)
{
	struct resource *res, *mem;
	int ret;

	/* reserve static register mappings */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENOENT;

	mem = request_mem_region(res->start, res->end - res->start + 1,
				 pdev->name);
	if (mem == NULL)
		return -EBUSY;

	platform_set_drvdata(pdev, mem);

	omap_wdt_users = 0;

	if (cpu_is_omap16xx()) {
		armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
		if (IS_ERR(armwdt_ck)) {
			ret = PTR_ERR(armwdt_ck);
			armwdt_ck = NULL;
			goto fail;
		}
	}

	if (cpu_is_omap24xx()) {
		mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
		if (IS_ERR(mpu_wdt_ick)) {
			ret = PTR_ERR(mpu_wdt_ick);
			mpu_wdt_ick = NULL;
			goto fail;
		}
		mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
		if (IS_ERR(mpu_wdt_fck)) {
			ret = PTR_ERR(mpu_wdt_fck);
			mpu_wdt_fck = NULL;
			goto fail;
		}
	}

	omap_wdt_disable();
	omap_wdt_adjust_timeout(timer_margin);

	omap_wdt_miscdev.dev = &pdev->dev;
	ret = misc_register(&omap_wdt_miscdev);
	if (ret)
		goto fail;

	pr_info("OMAP Watchdog Timer: initial timeout %d sec\n", timer_margin);

	/* autogate OCP interface clock */
	omap_writel(0x01, OMAP_WATCHDOG_SYS_CONFIG);
	return 0;

fail:
	if (armwdt_ck)
		clk_put(armwdt_ck);
	if (mpu_wdt_ick)
		clk_put(mpu_wdt_ick);
	if (mpu_wdt_fck)
		clk_put(mpu_wdt_fck);
	release_resource(mem);
	return ret;
}

static void omap_wdt_shutdown(struct platform_device *pdev)
{
	omap_wdt_disable();
}

static int omap_wdt_remove(struct platform_device *pdev)
{
	struct resource *mem = platform_get_drvdata(pdev);
	misc_deregister(&omap_wdt_miscdev);
	release_resource(mem);
	if (armwdt_ck)
		clk_put(armwdt_ck);
	if (mpu_wdt_ick)
		clk_put(mpu_wdt_ick);
	if (mpu_wdt_fck)
		clk_put(mpu_wdt_fck);
	return 0;
}

#ifdef	CONFIG_PM

/* REVISIT ... not clear this is the best way to handle system suspend; and
 * it's very inappropriate for selective device suspend (e.g. suspending this
 * through sysfs rather than by stopping the watchdog daemon).  Also, this
 * may not play well enough with NOWAYOUT...
 */

static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
{
	if (omap_wdt_users)
		omap_wdt_disable();
	return 0;
}

static int omap_wdt_resume(struct platform_device *pdev)
{
	if (omap_wdt_users) {
		omap_wdt_enable();
		omap_wdt_ping();
	}
	return 0;
}

#else
#define	omap_wdt_suspend	NULL
#define	omap_wdt_resume		NULL
#endif

static struct platform_driver omap_wdt_driver = {
	.probe		= omap_wdt_probe,
	.remove		= omap_wdt_remove,
	.shutdown	= omap_wdt_shutdown,
	.suspend	= omap_wdt_suspend,
	.resume		= omap_wdt_resume,
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= "omap_wdt",
	},
};

static int __init omap_wdt_init(void)
{
	return platform_driver_register(&omap_wdt_driver);
}

static void __exit omap_wdt_exit(void)
{
	platform_driver_unregister(&omap_wdt_driver);
}

module_init(omap_wdt_init);
module_exit(omap_wdt_exit);

MODULE_AUTHOR("George G. Davis");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
OpenPOWER on IntegriCloud