aboutsummaryrefslogtreecommitdiff
path: root/drivers/watchdog/sa1100_wdt.c
blob: 82ac5d19f519e281a4289aca02c5161844808233 (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
// SPDX-License-Identifier: GPL-2.0+
/*
 *	Watchdog driver for the SA11x0/PXA2xx
 *
 *	(c) Copyright 2000 Oleg Drokin <green@crimea.edu>
 *	    Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 *	Neither Oleg Drokin nor iXcelerator.com admit liability nor provide
 *	warranty for any of this software. This material is provided
 *	"AS-IS" and at no charge.
 *
 *	(c) Copyright 2000           Oleg Drokin <green@crimea.edu>
 *
 *	27/11/2000 Initial release
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/clk.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <linux/timex.h>

#define REG_OSMR0  	0x0000  /* OS timer Match Reg. 0 */
#define REG_OSMR1  	0x0004  /* OS timer Match Reg. 1 */
#define REG_OSMR2  	0x0008  /* OS timer Match Reg. 2 */
#define REG_OSMR3  	0x000c  /* OS timer Match Reg. 3 */
#define REG_OSCR   	0x0010  /* OS timer Counter Reg. */
#define REG_OSSR   	0x0014  /* OS timer Status Reg. */
#define REG_OWER   	0x0018  /* OS timer Watch-dog Enable Reg. */
#define REG_OIER  	0x001C  /* OS timer Interrupt Enable Reg. */

#define OSSR_M3		(1 << 3)	/* Match status channel 3 */
#define OSSR_M2		(1 << 2)	/* Match status channel 2 */
#define OSSR_M1		(1 << 1)	/* Match status channel 1 */
#define OSSR_M0		(1 << 0)	/* Match status channel 0 */

#define OWER_WME	(1 << 0)	/* Watchdog Match Enable */

#define OIER_E3		(1 << 3)	/* Interrupt enable channel 3 */
#define OIER_E2		(1 << 2)	/* Interrupt enable channel 2 */
#define OIER_E1		(1 << 1)	/* Interrupt enable channel 1 */
#define OIER_E0		(1 << 0)	/* Interrupt enable channel 0 */

static unsigned long oscr_freq;
static unsigned long sa1100wdt_users;
static unsigned int pre_margin;
static int boot_status;
static void __iomem *reg_base;

static inline void sa1100_wr(u32 val, u32 offset)
{
	writel_relaxed(val, reg_base + offset);
}

static inline u32 sa1100_rd(u32 offset)
{
	return readl_relaxed(reg_base + offset);
}

/*
 *	Allow only one person to hold it open
 */
static int sa1100dog_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(1, &sa1100wdt_users))
		return -EBUSY;

	/* Activate SA1100 Watchdog timer */
	sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
	sa1100_wr(OSSR_M3, REG_OSSR);
	sa1100_wr(OWER_WME, REG_OWER);
	sa1100_wr(sa1100_rd(REG_OIER) | OIER_E3, REG_OIER);
	return stream_open(inode, file);
}

/*
 * The watchdog cannot be disabled.
 *
 * Previous comments suggested that turning off the interrupt by
 * clearing REG_OIER[E3] would prevent the watchdog timing out but this
 * does not appear to be true (at least on the PXA255).
 */
static int sa1100dog_release(struct inode *inode, struct file *file)
{
	pr_crit("Device closed - timer will not stop\n");
	clear_bit(1, &sa1100wdt_users);
	return 0;
}

static ssize_t sa1100dog_write(struct file *file, const char __user *data,
						size_t len, loff_t *ppos)
{
	if (len)
		/* Refresh OSMR3 timer. */
		sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
	return len;
}

static const struct watchdog_info ident = {
	.options	= WDIOF_CARDRESET | WDIOF_SETTIMEOUT
				| WDIOF_KEEPALIVEPING,
	.identity	= "SA1100/PXA255 Watchdog",
	.firmware_version	= 1,
};

static long sa1100dog_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	int ret = -ENOTTY;
	int time;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = copy_to_user(argp, &ident,
				   sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
		ret = put_user(0, p);
		break;

	case WDIOC_GETBOOTSTATUS:
		ret = put_user(boot_status, p);
		break;

	case WDIOC_KEEPALIVE:
		sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
		ret = 0;
		break;

	case WDIOC_SETTIMEOUT:
		ret = get_user(time, p);
		if (ret)
			break;

		if (time <= 0 || (oscr_freq * (long long)time >= 0xffffffff)) {
			ret = -EINVAL;
			break;
		}

		pre_margin = oscr_freq * time;
		sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
		fallthrough;

	case WDIOC_GETTIMEOUT:
		ret = put_user(pre_margin / oscr_freq, p);
		break;
	}
	return ret;
}

static const struct file_operations sa1100dog_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= sa1100dog_write,
	.unlocked_ioctl	= sa1100dog_ioctl,
	.compat_ioctl	= compat_ptr_ioctl,
	.open		= sa1100dog_open,
	.release	= sa1100dog_release,
};

static struct miscdevice sa1100dog_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &sa1100dog_fops,
};

static int margin = 60;		/* (secs) Default is 1 minute */
static struct clk *clk;

static int sa1100dog_probe(struct platform_device *pdev)
{
	int ret;
	int *platform_data;
	struct resource *res;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENXIO;
	reg_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
	ret = PTR_ERR_OR_ZERO(reg_base);
	if (ret)
		return ret;

	clk = clk_get(NULL, "OSTIMER0");
	if (IS_ERR(clk)) {
		pr_err("SA1100/PXA2xx Watchdog Timer: clock not found: %d\n",
		       (int) PTR_ERR(clk));
		return PTR_ERR(clk);
	}

	ret = clk_prepare_enable(clk);
	if (ret) {
		pr_err("SA1100/PXA2xx Watchdog Timer: clock failed to prepare+enable: %d\n",
		       ret);
		goto err;
	}

	oscr_freq = clk_get_rate(clk);

	platform_data = pdev->dev.platform_data;
	if (platform_data && *platform_data)
		boot_status = WDIOF_CARDRESET;
	pre_margin = oscr_freq * margin;

	ret = misc_register(&sa1100dog_miscdev);
	if (ret == 0) {
		pr_info("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
			margin);
		return 0;
	}

	clk_disable_unprepare(clk);
err:
	clk_put(clk);
	return ret;
}

static int sa1100dog_remove(struct platform_device *pdev)
{
	misc_deregister(&sa1100dog_miscdev);
	clk_disable_unprepare(clk);
	clk_put(clk);

	return 0;
}

static struct platform_driver sa1100dog_driver = {
	.driver.name = "sa1100_wdt",
	.probe	  = sa1100dog_probe,
	.remove	  = sa1100dog_remove,
};
module_platform_driver(sa1100dog_driver);

MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");

module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");

MODULE_LICENSE("GPL");