target/linux/amazon/files/drivers/char/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/module.h>
  21 #include <linux/init.h>
  22 #include <linux/sched.h>
  23 #include <linux/kernel.h>
  24 #include <linux/slab.h>
  25 #include <linux/string.h>
  26 #include <linux/timer.h>
  27 #include <linux/fs.h>
  28 #include <linux/errno.h>
  29 #include <linux/proc_fs.h>
  30 #include <linux/stat.h>
  31 #include <linux/tty.h>
  32 #include <linux/selection.h>
  33 #include <linux/kmod.h>
  34 #include <linux/vmalloc.h>
  35 #include <linux/kdev_t.h>
  36 #include <linux/ioctl.h>
  37 #include <asm/uaccess.h>
  38 #include <asm/system.h>
  39 #include <asm/amazon/amazon.h>
  40 #include <asm/amazon/amazon_wdt.h>
  41
  42 #define DRV_NAME "AMAZON WDT:"
  43
  44 #undef AMAZON_WDT_DEBUG
  45
  46 extern unsigned int amazon_get_fpi_hz(void);
  47 static int amazon_wdt_isopen = 0;
  48
  49 #ifdef AMAZON_WDT_DEBUG
  50 static struct proc_dir_entry* amazon_wdt_dir;
  51 #endif
  52
  53 int wdt_enable(int timeout)
  54 {
  55         u32 hard_psw, ffpi;
  56         int reload_value, divider = 1;
  57
  58         ffpi = amazon_get_fpi_hz();
  59
  60         reload_value = 65536 - timeout * ffpi / 256;
  61
  62         if (reload_value < 0) {
  63                 divider = 0;
  64                 reload_value = 65536 - timeout * ffpi / 16384;
  65         }
  66
  67         if (reload_value < 0){
  68                 printk(KERN_INFO DRV_NAME "timeout too large %d\n", timeout);
  69                 return -EINVAL;
  70         }
  71
  72         printk(KERN_INFO DRV_NAME "timeout:%d reload_value: %8x\n", timeout, reload_value);
  73
  74         hard_psw = (amazon_readl(AMAZON_WDT_CON0) & 0xffffff01) +
  75                                 (amazon_readl(AMAZON_WDT_CON1) & 0xc) + 0xf0;
  76         amazon_writel(hard_psw, AMAZON_WDT_CON0);
  77         wmb();
  78
  79         amazon_writel((hard_psw & 0xff00) + (reload_value << 16) + 0xf2, AMAZON_WDT_CON0);
  80         wmb();
  81
  82         amazon_writel(divider << 2, AMAZON_WDT_CON1);
  83         wmb();
  84
  85         hard_psw = (amazon_readl(AMAZON_WDT_CON0) & 0xffffff01) +
  86                                 (amazon_readl(AMAZON_WDT_CON1) & 0xc) + 0xf0;
  87         amazon_writel(hard_psw, AMAZON_WDT_CON0);
  88         wmb();
  89
  90         amazon_writel_masked(AMAZON_WDT_CON0, 0xff, 0xf3);
  91         wmb();
  92         return 0;
  93 }
  94
  95 void wdt_disable(void)
  96 {
  97         u32 hard_psw = 0;
  98
  99         hard_psw = (amazon_readl(AMAZON_WDT_CON0) & 0xffffff01) +
 100                         (amazon_readl(AMAZON_WDT_CON1) & 0xc) + 0xf0;
 101         amazon_writel(hard_psw, AMAZON_WDT_CON0);
 102         wmb();
 103
 104         amazon_writel_masked(AMAZON_WDT_CON0, 0xff, 0xf2);
 105         wmb();
 106
 107         amazon_writel_masked(AMAZON_WDT_CON1, 0x8, 0x8);
 108         wmb();
 109
 110         hard_psw=(amazon_readl(AMAZON_WDT_CON0) & 0xffffff01) +
 111                         (amazon_readl(AMAZON_WDT_CON1) & 0xc) + 0xf0;
 112         amazon_writel(hard_psw, AMAZON_WDT_CON0);
 113         wmb();
 114
 115         amazon_writel_masked(AMAZON_WDT_CON0, 0xff, 0xf3);
 116         wmb();
 117
 118         return;
 119 }
 120
 121 static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 122 {
 123         int result=0;
 124         static int timeout=-1;
 125
 126         switch(cmd){
 127                 case AMAZON_WDT_IOC_START:
 128                         printk(KERN_INFO DRV_NAME "enable watch dog timer!\n");
 129                         if (copy_from_user((void*)&timeout, (void*)arg, sizeof (int))) {
 130                                 printk(KERN_INFO DRV_NAME "invalid argument\n");
 131                                 result=-EINVAL;
 132                         } else if ((result = wdt_enable(timeout)) < 0) {
 133                                 timeout = -1;
 134                         }
 135                         break;
 136
 137                 case AMAZON_WDT_IOC_STOP:
 138                         printk(KERN_INFO DRV_NAME "disable watch dog timer\n");
 139                         timeout = -1;
 140                         wdt_disable();
 141                         break;
 142
 143                 case AMAZON_WDT_IOC_PING:
 144                         if (timeout < 0) {
 145                                 result = -EIO;
 146                         } else {
 147                                 result = wdt_enable(timeout);
 148                         }
 149                         break;
 150
 151                 default:
 152                         result=-EINVAL;
 153                         break;
 154         }
 155         return result;
 156 }
 157
 158 static ssize_t wdt_read(struct file *file, char *buf, size_t count, loff_t *offset)
 159 {
 160         return 0;
 161 }
 162
 163 static ssize_t wdt_write(struct file *file, const char *buf, size_t count, loff_t *offset)
 164 {
 165         return count;
 166 }
 167
 168 static int wdt_open(struct inode *inode, struct file *file)
 169 {
 170         if (amazon_wdt_isopen == 1)
 171                 return -EBUSY;
 172
 173         amazon_wdt_isopen = 1;
 174         printk(KERN_INFO DRV_NAME "opened\n");
 175         return 0;
 176 }
 177
 178 static int wdt_release(struct inode *inode, struct file *file)
 179 {
 180         amazon_wdt_isopen = 0;
 181         printk(KERN_INFO DRV_NAME "closed\n");
 182         return 0;
 183 }
 184
 185 #ifdef AMAZON_WDT_DEBUG
 186 int wdt_register_proc_read(char *buf, char **start, off_t offset,
 187                          int count, int *eof, void *data)
 188 {
 189         int len=0;
 190         len+=sprintf(buf+len,"NMISR:    0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_NMISR));
 191         len+=sprintf(buf+len,"RST_REQ:  0x%08x\n",AMAZON_WDT_REG32(AMAZON_RST_REQ));
 192         len+=sprintf(buf+len,"RST_SR:   0x%08x\n",AMAZON_WDT_REG32(AMAZON_RST_SR));
 193         len+=sprintf(buf+len,"WDT_CON0: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_CON0));
 194         len+=sprintf(buf+len,"WDT_CON1: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_CON1));
 195         len+=sprintf(buf+len,"WDT_SR:   0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_SR));
 196         *eof = 1;
 197         return len;
 198 }
 199 #endif
 200
 201 static struct file_operations wdt_fops = {
 202         read:           wdt_read,
 203         write:          wdt_write,
 204         ioctl:          wdt_ioctl,
 205         open:           wdt_open,
 206         release:        wdt_release,
 207 };
 208
 209 int __init amazon_wdt_init_module(void)
 210 {
 211         int result = result = register_chrdev(0, "watchdog", &wdt_fops);
 212
 213         if (result < 0) {
 214         printk(KERN_INFO DRV_NAME "cannot register device\n");
 215         return result;
 216         }
 217
 218 #ifdef AMAZON_WDT_DEBUG
 219         amazon_wdt_dir=proc_mkdir("amazon_wdt",NULL);
 220         create_proc_read_entry("wdt_register", 0, amazon_wdt_dir,
 221                                 wdt_register_proc_read, NULL);
 222 #endif
 223
 224         amazon_wdt_isopen=0;
 225         printk(KERN_INFO DRV_NAME "driver loaded but inactive");
 226         return 0;
 227 }
 228
 229 void amazon_wdt_cleanup_module(void)
 230 {
 231         unregister_chrdev(0, "watchdog");
 232 #ifdef AMAZON_WDT_DEBUG
 233         remove_proc_entry("wdt_register", amazon_wdt_dir);
 234         remove_proc_entry("amazon_wdt", NULL);
 235 #endif
 236         printk(KERN_INFO DRV_NAME "unregistered");
 237         return;
 238 }
 239
 240 MODULE_LICENSE ("GPL");
 241 MODULE_AUTHOR("Infineon / John Crispin <blogic@openwrt.org>");
 242 MODULE_DESCRIPTION("AMAZON WDT driver");
 243
 244 module_init(amazon_wdt_init_module);
 245 module_exit(amazon_wdt_cleanup_module);
 246