1/*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
10 * GNU General Public License for more details.
11 *
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
15 *
16 * Copyright 2004 Wu Qi Ming <gokimi@msn.com>
17 * Copyright (C) 2007 John Crispin <blogic@openwrt.org>
18 */
19
20#include <linux/version.h>
21#include <linux/module.h>
22#include <linux/init.h>
23#include <linux/sched.h>
24#include <linux/kernel.h>
25#include <linux/slab.h>
26#include <linux/string.h>
27#include <linux/timer.h>
28#include <linux/fs.h>
29#include <linux/errno.h>
30#include <linux/proc_fs.h>
31#include <linux/stat.h>
32#include <linux/tty.h>
33#include <linux/selection.h>
34#include <linux/kmod.h>
35#include <linux/vmalloc.h>
36#include <linux/kdev_t.h>
37#include <linux/ioctl.h>
38#include <asm/uaccess.h>
39#include <asm/system.h>
40#include <linux/platform_device.h>
41#include <asm/amazon/amazon.h>
42#include <asm/amazon/amazon_wdt.h>
43
44#define DRV_NAME "AMAZON WDT:"
45
46#undef AMAZON_WDT_DEBUG
47
48static int amazon_wdt_isopen = 0;
49
50#ifdef AMAZON_WDT_DEBUG
51static struct proc_dir_entry* amazon_wdt_dir;
52#endif
53
54int wdt_enable(int timeout)
55{
56  	u32 hard_psw, ffpi;
57  	int reload_value, divider = 1;
58
59	ffpi = amazon_get_fpi_hz();
60
61	reload_value = 65536 - timeout * ffpi / 256;
62
63	if (reload_value < 0) {
64		divider = 0;
65		reload_value = 65536 - timeout * ffpi / 16384;
66  	}
67
68	if (reload_value < 0){
69		printk(KERN_INFO DRV_NAME "timeout too large %d\n", timeout);
70		return -EINVAL;
71	}
72
73	printk(KERN_INFO DRV_NAME "timeout:%d reload_value: %8x\n", timeout, reload_value);
74
75	hard_psw = (amazon_readl(AMAZON_WDT_CON0) & 0xffffff01) +
76				(amazon_readl(AMAZON_WDT_CON1) & 0xc) + 0xf0;
77  	amazon_writel(hard_psw, AMAZON_WDT_CON0);
78  	wmb();
79
80	amazon_writel((hard_psw & 0xff00) + (reload_value << 16) + 0xf2, AMAZON_WDT_CON0);
81  	wmb();
82
83  	amazon_writel(divider << 2, AMAZON_WDT_CON1);
84	wmb();
85
86  	hard_psw = (amazon_readl(AMAZON_WDT_CON0) & 0xffffff01) +
87				(amazon_readl(AMAZON_WDT_CON1) & 0xc) + 0xf0;
88  	amazon_writel(hard_psw, AMAZON_WDT_CON0);
89	wmb();
90
91	amazon_writel_masked(AMAZON_WDT_CON0, 0xff, 0xf3);
92	wmb();
93	return 0;
94}
95
96void wdt_disable(void)
97{
98	u32 hard_psw = 0;
99
100	hard_psw = (amazon_readl(AMAZON_WDT_CON0) & 0xffffff01) +
101			(amazon_readl(AMAZON_WDT_CON1) & 0xc) + 0xf0;
102	amazon_writel(hard_psw, AMAZON_WDT_CON0);
103	wmb();
104
105	amazon_writel_masked(AMAZON_WDT_CON0, 0xff, 0xf2);
106	wmb();
107
108	amazon_writel_masked(AMAZON_WDT_CON1, 0x8, 0x8);
109	wmb();
110
111	hard_psw=(amazon_readl(AMAZON_WDT_CON0) & 0xffffff01) +
112			(amazon_readl(AMAZON_WDT_CON1) & 0xc) + 0xf0;
113	amazon_writel(hard_psw, AMAZON_WDT_CON0);
114	wmb();
115
116	amazon_writel_masked(AMAZON_WDT_CON0, 0xff, 0xf3);
117	wmb();
118
119   	return;
120}
121
122#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36))
123static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
124#else
125static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
126#endif
127{
128	int result=0;
129	static int timeout=-1;
130
131	switch(cmd){
132		case AMAZON_WDT_IOC_START:
133			printk(KERN_INFO DRV_NAME "enable watch dog timer!\n");
134			if (copy_from_user((void*)&timeout, (void*)arg, sizeof (int))) {
135				printk(KERN_INFO DRV_NAME "invalid argument\n");
136				result=-EINVAL;
137			} else if ((result = wdt_enable(timeout)) < 0) {
138				timeout = -1;
139			}
140			break;
141
142		case AMAZON_WDT_IOC_STOP:
143			printk(KERN_INFO DRV_NAME "disable watch dog timer\n");
144			timeout = -1;
145			wdt_disable();
146			break;
147
148		case AMAZON_WDT_IOC_PING:
149			if (timeout < 0) {
150				result = -EIO;
151			} else {
152				result = wdt_enable(timeout);
153			}
154			break;
155
156		default:
157			result=-EINVAL;
158			break;
159	}
160	return result;
161}
162
163static ssize_t wdt_read(struct file *file, char *buf, size_t count, loff_t *offset)
164{
165	return 0;
166}
167
168static ssize_t wdt_write(struct file *file, const char *buf, size_t count, loff_t *offset)
169{
170	return count;
171}
172
173static int wdt_open(struct inode *inode, struct file *file)
174{
175	if (amazon_wdt_isopen == 1)
176		return -EBUSY;
177
178	amazon_wdt_isopen = 1;
179	printk(KERN_INFO DRV_NAME "opened\n");
180	return 0;
181}
182
183static int wdt_release(struct inode *inode, struct file *file)
184{
185	amazon_wdt_isopen = 0;
186	printk(KERN_INFO DRV_NAME "closed\n");
187	return 0;
188}
189
190#ifdef AMAZON_WDT_DEBUG
191int wdt_register_proc_read(char *buf, char **start, off_t offset,
192                         int count, int *eof, void *data)
193{
194   	int len=0;
195   	len+=sprintf(buf+len,"NMISR:    0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_NMISR));
196   	len+=sprintf(buf+len,"RST_REQ:  0x%08x\n",AMAZON_WDT_REG32(AMAZON_RST_REQ));
197   	len+=sprintf(buf+len,"RST_SR:   0x%08x\n",AMAZON_WDT_REG32(AMAZON_RST_SR));
198   	len+=sprintf(buf+len,"WDT_CON0: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_CON0));
199   	len+=sprintf(buf+len,"WDT_CON1: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_CON1));
200   	len+=sprintf(buf+len,"WDT_SR:   0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_SR));
201   	*eof = 1;
202   	return len;
203}
204#endif
205
206static struct file_operations wdt_fops = {
207	read:		wdt_read,
208	write:		wdt_write,
209#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36))
210	unlocked_ioctl:	wdt_ioctl,
211#else
212	ioctl:		wdt_ioctl,
213#endif
214	open:		wdt_open,
215	release:	wdt_release,
216};
217
218static int amazon_wdt_probe(struct platform_device *dev)
219{
220	int result = result = register_chrdev(0, "watchdog", &wdt_fops);
221
222	if (result < 0) {
223        printk(KERN_INFO DRV_NAME "cannot register device\n");
224       	return result;
225   	}
226
227#ifdef AMAZON_WDT_DEBUG
228	amazon_wdt_dir=proc_mkdir("amazon_wdt",NULL);
229   	create_proc_read_entry("wdt_register", 0, amazon_wdt_dir,
230                          	wdt_register_proc_read, NULL);
231#endif
232
233	amazon_wdt_isopen=0;
234	printk(KERN_INFO DRV_NAME "driver loaded but inactive\n");
235	return 0;
236}
237
238static int amazon_wdt_remove(struct platform_device *dev)
239{
240	unregister_chrdev(0, "watchdog");
241#ifdef AMAZON_WDT_DEBUG
242	remove_proc_entry("wdt_register", amazon_wdt_dir);
243	remove_proc_entry("amazon_wdt", NULL);
244#endif
245	printk(KERN_INFO DRV_NAME "unregistered\n");
246	return 0;
247}
248
249static struct platform_driver amazon_wdt_driver = {
250	.probe = amazon_wdt_probe,
251	.remove = amazon_wdt_remove,
252	.driver = {
253		.name = "amazon_wdt",
254		.owner = THIS_MODULE,
255	},
256};
257
258static int __init amazon_wdt_init(void)
259{
260	int ret = platform_driver_register(&amazon_wdt_driver);
261	if (ret)
262		printk(KERN_WARNING "amazon_wdt: error registering platfom driver!\n");
263	return ret;
264}
265
266static void __exit amazon_wdt_exit(void)
267{
268	platform_driver_unregister(&amazon_wdt_driver);
269}
270
271module_init(amazon_wdt_init);
272module_exit(amazon_wdt_exit);
273
274MODULE_LICENSE ("GPL");
275MODULE_AUTHOR("Infineon / John Crispin <blogic@openwrt.org>");
276MODULE_DESCRIPTION("AMAZON WDT driver");
277
278