release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/watchdog/orion_wdt.c

   1 /*
   2  * drivers/watchdog/orion_wdt.c
   3  *
   4  * Watchdog driver for Orion/Kirkwood processors
   5  *
   6  * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
   7  *
   8  * This file is licensed under  the terms of the GNU General Public
   9  * License version 2. This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/fs.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/watchdog.h>
  21 #include <linux/init.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/io.h>
  24 #include <linux/spinlock.h>
  25 #include <mach/bridge-regs.h>
  26 #include <plat/orion_wdt.h>
  27
  28 /*
  29  * Watchdog timer block registers.
  30  */
  31 #define TIMER_CTRL              (TIMER_VIRT_BASE + 0x0000)
  32 #define  WDT_EN                 0x0010
  33 #define WDT_VAL                 (TIMER_VIRT_BASE + 0x0024)
  34
  35 #define WDT_MAX_CYCLE_COUNT     0xffffffff
  36 #define WDT_IN_USE              0
  37 #define WDT_OK_TO_CLOSE         1
  38
  39 static int nowayout = WATCHDOG_NOWAYOUT;
  40 static int heartbeat = -1;              /* module parameter (seconds) */
  41 static unsigned int wdt_max_duration;   /* (seconds) */
  42 static unsigned int wdt_tclk;
  43 static unsigned long wdt_status;
  44 static spinlock_t wdt_lock;
  45
  46 static void orion_wdt_ping(void)
  47 {
  48         spin_lock(&wdt_lock);
  49
  50         /* Reload watchdog duration */
  51         writel(wdt_tclk * heartbeat, WDT_VAL);
  52
  53         spin_unlock(&wdt_lock);
  54 }
  55
  56 static void orion_wdt_enable(void)
  57 {
  58         u32 reg;
  59
  60         spin_lock(&wdt_lock);
  61
  62         /* Set watchdog duration */
  63         writel(wdt_tclk * heartbeat, WDT_VAL);
  64
  65         /* Clear watchdog timer interrupt */
  66         reg = readl(BRIDGE_CAUSE);
  67         reg &= ~WDT_INT_REQ;
  68         writel(reg, BRIDGE_CAUSE);
  69
  70         /* Enable watchdog timer */
  71         reg = readl(TIMER_CTRL);
  72         reg |= WDT_EN;
  73         writel(reg, TIMER_CTRL);
  74
  75         /* Enable reset on watchdog */
  76         reg = readl(RSTOUTn_MASK);
  77         reg |= WDT_RESET_OUT_EN;
  78         writel(reg, RSTOUTn_MASK);
  79
  80         spin_unlock(&wdt_lock);
  81 }
  82
  83 static void orion_wdt_disable(void)
  84 {
  85         u32 reg;
  86
  87         spin_lock(&wdt_lock);
  88
  89         /* Disable reset on watchdog */
  90         reg = readl(RSTOUTn_MASK);
  91         reg &= ~WDT_RESET_OUT_EN;
  92         writel(reg, RSTOUTn_MASK);
  93
  94         /* Disable watchdog timer */
  95         reg = readl(TIMER_CTRL);
  96         reg &= ~WDT_EN;
  97         writel(reg, TIMER_CTRL);
  98
  99         spin_unlock(&wdt_lock);
 100 }
 101
 102 static int orion_wdt_get_timeleft(int *time_left)
 103 {
 104         spin_lock(&wdt_lock);
 105         *time_left = readl(WDT_VAL) / wdt_tclk;
 106         spin_unlock(&wdt_lock);
 107         return 0;
 108 }
 109
 110 static int orion_wdt_open(struct inode *inode, struct file *file)
 111 {
 112         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
 113                 return -EBUSY;
 114         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 115         orion_wdt_enable();
 116         return nonseekable_open(inode, file);
 117 }
 118
 119 static ssize_t orion_wdt_write(struct file *file, const char *data,
 120                                         size_t len, loff_t *ppos)
 121 {
 122         if (len) {
 123                 if (!nowayout) {
 124                         size_t i;
 125
 126                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 127                         for (i = 0; i != len; i++) {
 128                                 char c;
 129
 130                                 if (get_user(c, data + i))
 131                                         return -EFAULT;
 132                                 if (c == 'V')
 133                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
 134                         }
 135                 }
 136                 orion_wdt_ping();
 137         }
 138         return len;
 139 }
 140
 141 static int orion_wdt_settimeout(int new_time)
 142 {
 143         if ((new_time <= 0) || (new_time > wdt_max_duration))
 144                 return -EINVAL;
 145
 146         /* Set new watchdog time to be used when
 147          * orion_wdt_enable() or orion_wdt_ping() is called. */
 148         heartbeat = new_time;
 149         return 0;
 150 }
 151
 152 static const struct watchdog_info ident = {
 153         .options        = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
 154                           WDIOF_KEEPALIVEPING,
 155         .identity       = "Orion Watchdog",
 156 };
 157
 158 static long orion_wdt_ioctl(struct file *file, unsigned int cmd,
 159                                 unsigned long arg)
 160 {
 161         int ret = -ENOTTY;
 162         int time;
 163
 164         switch (cmd) {
 165         case WDIOC_GETSUPPORT:
 166                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
 167                                    sizeof(ident)) ? -EFAULT : 0;
 168                 break;
 169
 170         case WDIOC_GETSTATUS:
 171         case WDIOC_GETBOOTSTATUS:
 172                 ret = put_user(0, (int *)arg);
 173                 break;
 174
 175         case WDIOC_KEEPALIVE:
 176                 orion_wdt_ping();
 177                 ret = 0;
 178                 break;
 179
 180         case WDIOC_SETTIMEOUT:
 181                 ret = get_user(time, (int *)arg);
 182                 if (ret)
 183                         break;
 184
 185                 if (orion_wdt_settimeout(time)) {
 186                         ret = -EINVAL;
 187                         break;
 188                 }
 189                 orion_wdt_ping();
 190                 /* Fall through */
 191
 192         case WDIOC_GETTIMEOUT:
 193                 ret = put_user(heartbeat, (int *)arg);
 194                 break;
 195
 196         case WDIOC_GETTIMELEFT:
 197                 if (orion_wdt_get_timeleft(&time)) {
 198                         ret = -EINVAL;
 199                         break;
 200                 }
 201                 ret = put_user(time, (int *)arg);
 202                 break;
 203         }
 204         return ret;
 205 }
 206
 207 static int orion_wdt_release(struct inode *inode, struct file *file)
 208 {
 209         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
 210                 orion_wdt_disable();
 211         else
 212                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
 213                                         "timer will not stop\n");
 214         clear_bit(WDT_IN_USE, &wdt_status);
 215         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 216
 217         return 0;
 218 }
 219
 220
 221 static const struct file_operations orion_wdt_fops = {
 222         .owner          = THIS_MODULE,
 223         .llseek         = no_llseek,
 224         .write          = orion_wdt_write,
 225         .unlocked_ioctl = orion_wdt_ioctl,
 226         .open           = orion_wdt_open,
 227         .release        = orion_wdt_release,
 228 };
 229
 230 static struct miscdevice orion_wdt_miscdev = {
 231         .minor          = WATCHDOG_MINOR,
 232         .name           = "watchdog",
 233         .fops           = &orion_wdt_fops,
 234 };
 235
 236 static int __devinit orion_wdt_probe(struct platform_device *pdev)
 237 {
 238         struct orion_wdt_platform_data *pdata = pdev->dev.platform_data;
 239         int ret;
 240
 241         if (pdata) {
 242                 wdt_tclk = pdata->tclk;
 243         } else {
 244                 printk(KERN_ERR "Orion Watchdog misses platform data\n");
 245                 return -ENODEV;
 246         }
 247
 248         if (orion_wdt_miscdev.parent)
 249                 return -EBUSY;
 250         orion_wdt_miscdev.parent = &pdev->dev;
 251
 252         wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
 253         if (orion_wdt_settimeout(heartbeat))
 254                 heartbeat = wdt_max_duration;
 255
 256         ret = misc_register(&orion_wdt_miscdev);
 257         if (ret)
 258                 return ret;
 259
 260         printk(KERN_INFO "Orion Watchdog Timer: Initial timeout %d sec%s\n",
 261                                 heartbeat, nowayout ? ", nowayout" : "");
 262         return 0;
 263 }
 264
 265 static int __devexit orion_wdt_remove(struct platform_device *pdev)
 266 {
 267         int ret;
 268
 269         if (test_bit(WDT_IN_USE, &wdt_status)) {
 270                 orion_wdt_disable();
 271                 clear_bit(WDT_IN_USE, &wdt_status);
 272         }
 273
 274         ret = misc_deregister(&orion_wdt_miscdev);
 275         if (!ret)
 276                 orion_wdt_miscdev.parent = NULL;
 277
 278         return ret;
 279 }
 280
 281 static void orion_wdt_shutdown(struct platform_device *pdev)
 282 {
 283         if (test_bit(WDT_IN_USE, &wdt_status))
 284                 orion_wdt_disable();
 285 }
 286
 287 static struct platform_driver orion_wdt_driver = {
 288         .probe          = orion_wdt_probe,
 289         .remove         = __devexit_p(orion_wdt_remove),
 290         .shutdown       = orion_wdt_shutdown,
 291         .driver         = {
 292                 .owner  = THIS_MODULE,
 293                 .name   = "orion_wdt",
 294         },
 295 };
 296
 297 static int __init orion_wdt_init(void)
 298 {
 299         spin_lock_init(&wdt_lock);
 300         return platform_driver_register(&orion_wdt_driver);
 301 }
 302
 303 static void __exit orion_wdt_exit(void)
 304 {
 305         platform_driver_unregister(&orion_wdt_driver);
 306 }
 307
 308 module_init(orion_wdt_init);
 309 module_exit(orion_wdt_exit);
 310
 311 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
 312 MODULE_DESCRIPTION("Orion Processor Watchdog");
 313
 314 module_param(heartbeat, int, 0);
 315 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
 316
 317 module_param(nowayout, int, 0);
 318 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 319                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 320
 321 MODULE_LICENSE("GPL");
 322 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);