aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/char/watchdog/mv64x60_wdt.c
blob: 20a6cbb0fbb8b3f3acc4f546e7163f84c3fb17e4 (plain) (blame)
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
/*
 * mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface
 *
 * Author: James Chapman <jchapman@katalix.com>
 *
 * Platform-specific setup code should configure the dog to generate
 * interrupt or reset as required.  This code only enables/disables
 * and services the watchdog.
 *
 * Derived from mpc8xx_wdt.c, with the following copyright.
 * 
 * 2002 (c) Florian Schirmer <jolt@tuxbox.org> 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.
 */

#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>

#include <asm/mv64x60.h>
#include <asm/uaccess.h>
#include <asm/io.h>

/* MV64x60 WDC (config) register access definitions */
#define MV64x60_WDC_CTL1_MASK	(3 << 24)
#define MV64x60_WDC_CTL1(val)	((val & 3) << 24)
#define MV64x60_WDC_CTL2_MASK	(3 << 26)
#define MV64x60_WDC_CTL2(val)	((val & 3) << 26)

/* Flags bits */
#define MV64x60_WDOG_FLAG_OPENED	0
#define MV64x60_WDOG_FLAG_ENABLED	1

static unsigned long wdt_flags;
static int wdt_status;
static void __iomem *mv64x60_regs;
static int mv64x60_wdt_timeout;

static void mv64x60_wdt_reg_write(u32 val)
{
	/* Allow write only to CTL1 / CTL2 fields, retaining values in
	 * other fields.
	 */
	u32 data = readl(mv64x60_regs + MV64x60_WDT_WDC);
	data &= ~(MV64x60_WDC_CTL1_MASK | MV64x60_WDC_CTL2_MASK);
	data |= val;
	writel(data, mv64x60_regs + MV64x60_WDT_WDC);
}

static void mv64x60_wdt_service(void)
{
	/* Write 01 followed by 10 to CTL2 */
	mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x01));
	mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x02));
}

static void mv64x60_wdt_handler_disable(void)
{
	if (test_and_clear_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
		/* Write 01 followed by 10 to CTL1 */
		mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
		mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
		printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
	}
}

static void mv64x60_wdt_handler_enable(void)
{
	if (!test_and_set_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
		/* Write 01 followed by 10 to CTL1 */
		mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
		mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
		printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
	}
}

static int mv64x60_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
		return -EBUSY;

	mv64x60_wdt_service();
	mv64x60_wdt_handler_enable();

	nonseekable_open(inode, file);

	return 0;
}

static int mv64x60_wdt_release(struct inode *inode, struct file *file)
{
	mv64x60_wdt_service();

#if !defined(CONFIG_WATCHDOG_NOWAYOUT)
	mv64x60_wdt_handler_disable();
#endif

	clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);

	return 0;
}

static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
				 size_t len, loff_t * ppos)
{
	if (len)
		mv64x60_wdt_service();

	return len;
}

static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
			     unsigned int cmd, unsigned long arg)
{
	int timeout;
	void __user *argp = (void __user *)arg;
	static struct watchdog_info info = {
		.options = WDIOF_KEEPALIVEPING,
		.firmware_version = 0,
		.identity = "MV64x60 watchdog",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &info, sizeof(info)))
			return -EFAULT;
		break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		if (put_user(wdt_status, (int __user *)argp))
			return -EFAULT;
		wdt_status &= ~WDIOF_KEEPALIVEPING;
		break;

	case WDIOC_GETTEMP:
		return -EOPNOTSUPP;

	case WDIOC_SETOPTIONS:
		return -EOPNOTSUPP;

	case WDIOC_KEEPALIVE:
		mv64x60_wdt_service();
		wdt_status |= WDIOF_KEEPALIVEPING;
		break;

	case WDIOC_SETTIMEOUT:
		return -EOPNOTSUPP;

	case WDIOC_GETTIMEOUT:
		timeout = mv64x60_wdt_timeout * HZ;
		if (put_user(timeout, (int __user *)argp))
			return -EFAULT;
		break;

	default:
		return -ENOIOCTLCMD;
	}

	return 0;
}

static struct file_operations mv64x60_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = mv64x60_wdt_write,
	.ioctl = mv64x60_wdt_ioctl,
	.open = mv64x60_wdt_open,
	.release = mv64x60_wdt_release,
};

static struct miscdevice mv64x60_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &mv64x60_wdt_fops,
};

static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
{
	struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
	int bus_clk = 133;

	mv64x60_wdt_timeout = 10;
	if (pdata) {
		mv64x60_wdt_timeout = pdata->timeout;
		bus_clk = pdata->bus_clk;
	}

	mv64x60_regs = mv64x60_get_bridge_vbase();

	writel((mv64x60_wdt_timeout * (bus_clk * 1000000)) >> 8,
	       mv64x60_regs + MV64x60_WDT_WDC);

	return misc_register(&mv64x60_wdt_miscdev);
}

static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
{
	misc_deregister(&mv64x60_wdt_miscdev);

	mv64x60_wdt_service();
	mv64x60_wdt_handler_disable();

	return 0;
}

static struct platform_driver mv64x60_wdt_driver = {
	.probe = mv64x60_wdt_probe,
	.remove = __devexit_p(mv64x60_wdt_remove),
	.driver = {
		.owner = THIS_MODULE,
		.name = MV64x60_WDT_NAME,
	},
};

static struct platform_device *mv64x60_wdt_dev;

static int __init mv64x60_wdt_init(void)
{
	int ret;

	printk(KERN_INFO "MV64x60 watchdog driver\n");

	mv64x60_wdt_dev = platform_device_alloc(MV64x60_WDT_NAME, -1);
	if (!mv64x60_wdt_dev) {
		ret = -ENOMEM;
		goto out;
	}

	ret = platform_device_add(mv64x60_wdt_dev);
	if (ret) {
		platform_device_put(mv64x60_wdt_dev);
		goto out;
	}

	ret = platform_driver_register(&mv64x60_wdt_driver);
	if (ret) {
		platform_device_unregister(mv64x60_wdt_dev);
		goto out;
	}

 out:
	return ret;
}

static void __exit mv64x60_wdt_exit(void)
{
	platform_driver_unregister(&mv64x60_wdt_driver);
	platform_device_unregister(mv64x60_wdt_dev);
}

module_init(mv64x60_wdt_init);
module_exit(mv64x60_wdt_exit);

MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
MODULE_DESCRIPTION("MV64x60 watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);