Root/target/linux/amazon/files/drivers/watchdog/amazon_wdt.c

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 __init 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

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