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/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 <linux/platform_device.h>
  40 #include <asm/amazon/amazon.h>
  41 #include <asm/amazon/amazon_wdt.h>
  42
  43 #define DRV_NAME "AMAZON WDT:"
  44
  45 #undef AMAZON_WDT_DEBUG
  46
  47 extern unsigned int amazon_get_fpi_hz(void);
  48 static int amazon_wdt_isopen = 0;
  49
  50 #ifdef AMAZON_WDT_DEBUG
  51 static struct proc_dir_entry* amazon_wdt_dir;
  52 #endif
  53
  54 int 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
  96 void 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 static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 123 {
 124         int result=0;
 125         static int timeout=-1;
 126
 127         switch(cmd){
 128                 case AMAZON_WDT_IOC_START:
 129                         printk(KERN_INFO DRV_NAME "enable watch dog timer!\n");
 130                         if (copy_from_user((void*)&timeout, (void*)arg, sizeof (int))) {
 131                                 printk(KERN_INFO DRV_NAME "invalid argument\n");
 132                                 result=-EINVAL;
 133                         } else if ((result = wdt_enable(timeout)) < 0) {
 134                                 timeout = -1;
 135                         }
 136                         break;
 137
 138                 case AMAZON_WDT_IOC_STOP:
 139                         printk(KERN_INFO DRV_NAME "disable watch dog timer\n");
 140                         timeout = -1;
 141                         wdt_disable();
 142                         break;
 143
 144                 case AMAZON_WDT_IOC_PING:
 145                         if (timeout < 0) {
 146                                 result = -EIO;
 147                         } else {
 148                                 result = wdt_enable(timeout);
 149                         }
 150                         break;
 151
 152                 default:
 153                         result=-EINVAL;
 154                         break;
 155         }
 156         return result;
 157 }
 158
 159 static ssize_t wdt_read(struct file *file, char *buf, size_t count, loff_t *offset)
 160 {
 161         return 0;
 162 }
 163
 164 static ssize_t wdt_write(struct file *file, const char *buf, size_t count, loff_t *offset)
 165 {
 166         return count;
 167 }
 168
 169 static int wdt_open(struct inode *inode, struct file *file)
 170 {
 171         if (amazon_wdt_isopen == 1)
 172                 return -EBUSY;
 173
 174         amazon_wdt_isopen = 1;
 175         printk(KERN_INFO DRV_NAME "opened\n");
 176         return 0;
 177 }
 178
 179 static int wdt_release(struct inode *inode, struct file *file)
 180 {
 181         amazon_wdt_isopen = 0;
 182         printk(KERN_INFO DRV_NAME "closed\n");
 183         return 0;
 184 }
 185
 186 #ifdef AMAZON_WDT_DEBUG
 187 int wdt_register_proc_read(char *buf, char **start, off_t offset,
 188                          int count, int *eof, void *data)
 189 {
 190         int len=0;
 191         len+=sprintf(buf+len,"NMISR:    0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_NMISR));
 192         len+=sprintf(buf+len,"RST_REQ:  0x%08x\n",AMAZON_WDT_REG32(AMAZON_RST_REQ));
 193         len+=sprintf(buf+len,"RST_SR:   0x%08x\n",AMAZON_WDT_REG32(AMAZON_RST_SR));
 194         len+=sprintf(buf+len,"WDT_CON0: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_CON0));
 195         len+=sprintf(buf+len,"WDT_CON1: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_CON1));
 196         len+=sprintf(buf+len,"WDT_SR:   0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_SR));
 197         *eof = 1;
 198         return len;
 199 }
 200 #endif
 201
 202 static struct file_operations wdt_fops = {
 203         read:           wdt_read,
 204         write:          wdt_write,
 205         ioctl:          wdt_ioctl,
 206         open:           wdt_open,
 207         release:        wdt_release,
 208 };
 209
 210 static int __init amazon_wdt_probe(struct platform_device *dev)
 211 {
 212         int result = result = register_chrdev(0, "watchdog", &wdt_fops);
 213
 214         if (result < 0) {
 215         printk(KERN_INFO DRV_NAME "cannot register device\n");
 216         return result;
 217         }
 218
 219 #ifdef AMAZON_WDT_DEBUG
 220         amazon_wdt_dir=proc_mkdir("amazon_wdt",NULL);
 221         create_proc_read_entry("wdt_register", 0, amazon_wdt_dir,
 222                                 wdt_register_proc_read, NULL);
 223 #endif
 224
 225         amazon_wdt_isopen=0;
 226         printk(KERN_INFO DRV_NAME "driver loaded but inactive\n");
 227         return 0;
 228 }
 229
 230 static int amazon_wdt_remove(struct platform_device *dev)
 231 {
 232         unregister_chrdev(0, "watchdog");
 233 #ifdef AMAZON_WDT_DEBUG
 234         remove_proc_entry("wdt_register", amazon_wdt_dir);
 235         remove_proc_entry("amazon_wdt", NULL);
 236 #endif
 237         printk(KERN_INFO DRV_NAME "unregistered\n");
 238         return 0;
 239 }
 240
 241 static struct platform_driver amazon_wdt_driver = {
 242         .probe = amazon_wdt_probe,
 243         .remove = amazon_wdt_remove,
 244         .driver = {
 245                 .name = "amazon_wdt",
 246                 .owner = THIS_MODULE,
 247         },
 248 };
 249
 250 static int __init amazon_wdt_init(void)
 251 {
 252         int ret = platform_driver_register(&amazon_wdt_driver);
 253         if (ret)
 254                 printk(KERN_WARNING "amazon_wdt: error registering platfom driver!\n");
 255         return ret;
 256 }
 257
 258 static void __exit amazon_wdt_exit(void)
 259 {
 260         platform_driver_unregister(&amazon_wdt_driver);
 261 }
 262
 263 module_init(amazon_wdt_init);
 264 module_exit(amazon_wdt_exit);
 265
 266 MODULE_LICENSE ("GPL");
 267 MODULE_AUTHOR("Infineon / John Crispin <blogic@openwrt.org>");
 268 MODULE_DESCRIPTION("AMAZON WDT driver");
 269