1/*
2 * mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface
3 *
4 * Author: James Chapman <jchapman@katalix.com>
5 *
6 * Platform-specific setup code should configure the dog to generate
7 * interrupt or reset as required.  This code only enables/disables
8 * and services the watchdog.
9 *
10 * Derived from mpc8xx_wdt.c, with the following copyright.
11 *
12 * 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
13 * the terms of the GNU General Public License version 2. This program
14 * is licensed "as is" without any warranty of any kind, whether express
15 * or implied.
16 */
17
18#include <linux/fs.h>
19#include <linux/init.h>
20#include <linux/kernel.h>
21#include <linux/miscdevice.h>
22#include <linux/module.h>
23#include <linux/watchdog.h>
24#include <linux/platform_device.h>
25
26#include <asm/mv64x60.h>
27#include <asm/uaccess.h>
28#include <asm/io.h>
29
30/* MV64x60 WDC (config) register access definitions */
31#define MV64x60_WDC_CTL1_MASK	(3 << 24)
32#define MV64x60_WDC_CTL1(val)	((val & 3) << 24)
33#define MV64x60_WDC_CTL2_MASK	(3 << 26)
34#define MV64x60_WDC_CTL2(val)	((val & 3) << 26)
35
36/* Flags bits */
37#define MV64x60_WDOG_FLAG_OPENED	0
38#define MV64x60_WDOG_FLAG_ENABLED	1
39
40static unsigned long wdt_flags;
41static int wdt_status;
42static void __iomem *mv64x60_regs;
43static int mv64x60_wdt_timeout;
44
45static void mv64x60_wdt_reg_write(u32 val)
46{
47	/* Allow write only to CTL1 / CTL2 fields, retaining values in
48	 * other fields.
49	 */
50	u32 data = readl(mv64x60_regs + MV64x60_WDT_WDC);
51	data &= ~(MV64x60_WDC_CTL1_MASK | MV64x60_WDC_CTL2_MASK);
52	data |= val;
53	writel(data, mv64x60_regs + MV64x60_WDT_WDC);
54}
55
56static void mv64x60_wdt_service(void)
57{
58	/* Write 01 followed by 10 to CTL2 */
59	mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x01));
60	mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x02));
61}
62
63static void mv64x60_wdt_handler_disable(void)
64{
65	if (test_and_clear_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
66		/* Write 01 followed by 10 to CTL1 */
67		mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
68		mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
69		printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
70	}
71}
72
73static void mv64x60_wdt_handler_enable(void)
74{
75	if (!test_and_set_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
76		/* Write 01 followed by 10 to CTL1 */
77		mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
78		mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
79		printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
80	}
81}
82
83static int mv64x60_wdt_open(struct inode *inode, struct file *file)
84{
85	if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
86		return -EBUSY;
87
88	mv64x60_wdt_service();
89	mv64x60_wdt_handler_enable();
90
91	nonseekable_open(inode, file);
92
93	return 0;
94}
95
96static int mv64x60_wdt_release(struct inode *inode, struct file *file)
97{
98	mv64x60_wdt_service();
99
100#if !defined(CONFIG_WATCHDOG_NOWAYOUT)
101	mv64x60_wdt_handler_disable();
102#endif
103
104	clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
105
106	return 0;
107}
108
109static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
110				 size_t len, loff_t * ppos)
111{
112	if (len)
113		mv64x60_wdt_service();
114
115	return len;
116}
117
118static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
119			     unsigned int cmd, unsigned long arg)
120{
121	int timeout;
122	void __user *argp = (void __user *)arg;
123	static struct watchdog_info info = {
124		.options = WDIOF_KEEPALIVEPING,
125		.firmware_version = 0,
126		.identity = "MV64x60 watchdog",
127	};
128
129	switch (cmd) {
130	case WDIOC_GETSUPPORT:
131		if (copy_to_user(argp, &info, sizeof(info)))
132			return -EFAULT;
133		break;
134
135	case WDIOC_GETSTATUS:
136	case WDIOC_GETBOOTSTATUS:
137		if (put_user(wdt_status, (int __user *)argp))
138			return -EFAULT;
139		wdt_status &= ~WDIOF_KEEPALIVEPING;
140		break;
141
142	case WDIOC_GETTEMP:
143		return -EOPNOTSUPP;
144
145	case WDIOC_SETOPTIONS:
146		return -EOPNOTSUPP;
147
148	case WDIOC_KEEPALIVE:
149		mv64x60_wdt_service();
150		wdt_status |= WDIOF_KEEPALIVEPING;
151		break;
152
153	case WDIOC_SETTIMEOUT:
154		return -EOPNOTSUPP;
155
156	case WDIOC_GETTIMEOUT:
157		timeout = mv64x60_wdt_timeout * HZ;
158		if (put_user(timeout, (int __user *)argp))
159			return -EFAULT;
160		break;
161
162	default:
163		return -ENOTTY;
164	}
165
166	return 0;
167}
168
169static const struct file_operations mv64x60_wdt_fops = {
170	.owner = THIS_MODULE,
171	.llseek = no_llseek,
172	.write = mv64x60_wdt_write,
173	.ioctl = mv64x60_wdt_ioctl,
174	.open = mv64x60_wdt_open,
175	.release = mv64x60_wdt_release,
176};
177
178static struct miscdevice mv64x60_wdt_miscdev = {
179	.minor = WATCHDOG_MINOR,
180	.name = "watchdog",
181	.fops = &mv64x60_wdt_fops,
182};
183
184static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
185{
186	struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
187	int bus_clk = 133;
188
189	mv64x60_wdt_timeout = 10;
190	if (pdata) {
191		mv64x60_wdt_timeout = pdata->timeout;
192		bus_clk = pdata->bus_clk;
193	}
194
195	mv64x60_regs = mv64x60_get_bridge_vbase();
196
197	writel((mv64x60_wdt_timeout * (bus_clk * 1000000)) >> 8,
198	       mv64x60_regs + MV64x60_WDT_WDC);
199
200	return misc_register(&mv64x60_wdt_miscdev);
201}
202
203static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
204{
205	misc_deregister(&mv64x60_wdt_miscdev);
206
207	mv64x60_wdt_service();
208	mv64x60_wdt_handler_disable();
209
210	return 0;
211}
212
213static struct platform_driver mv64x60_wdt_driver = {
214	.probe = mv64x60_wdt_probe,
215	.remove = __devexit_p(mv64x60_wdt_remove),
216	.driver = {
217		.owner = THIS_MODULE,
218		.name = MV64x60_WDT_NAME,
219	},
220};
221
222static struct platform_device *mv64x60_wdt_dev;
223
224static int __init mv64x60_wdt_init(void)
225{
226	int ret;
227
228	printk(KERN_INFO "MV64x60 watchdog driver\n");
229
230	mv64x60_wdt_dev = platform_device_alloc(MV64x60_WDT_NAME, -1);
231	if (!mv64x60_wdt_dev) {
232		ret = -ENOMEM;
233		goto out;
234	}
235
236	ret = platform_device_add(mv64x60_wdt_dev);
237	if (ret) {
238		platform_device_put(mv64x60_wdt_dev);
239		goto out;
240	}
241
242	ret = platform_driver_register(&mv64x60_wdt_driver);
243	if (ret) {
244		platform_device_unregister(mv64x60_wdt_dev);
245		goto out;
246	}
247
248 out:
249	return ret;
250}
251
252static void __exit mv64x60_wdt_exit(void)
253{
254	platform_driver_unregister(&mv64x60_wdt_driver);
255	platform_device_unregister(mv64x60_wdt_dev);
256}
257
258module_init(mv64x60_wdt_init);
259module_exit(mv64x60_wdt_exit);
260
261MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
262MODULE_DESCRIPTION("MV64x60 watchdog driver");
263MODULE_LICENSE("GPL");
264MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
265