drivers/watchdog/orion5x_wdt.c

   1 /*
   2  * drivers/watchdog/orion5x_wdt.c
   3  *
   4  * Watchdog driver for Orion5x 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 <plat/orion5x_wdt.h>
  26
  27 /*
  28  * Watchdog timer block registers.
  29  */
  30 #define TIMER_CTRL              (TIMER_VIRT_BASE + 0x0000)
  31 #define  WDT_EN                 0x0010
  32 #define WDT_VAL                 (TIMER_VIRT_BASE + 0x0024)
  33
  34 #define WDT_MAX_CYCLE_COUNT     0xffffffff
  35 #define WDT_IN_USE              0
  36 #define WDT_OK_TO_CLOSE         1
  37
  38 static int nowayout = WATCHDOG_NOWAYOUT;
  39 static int heartbeat = -1;              /* module parameter (seconds) */
  40 static unsigned int wdt_max_duration;   /* (seconds) */
  41 static unsigned int wdt_tclk;
  42 static unsigned long wdt_status;
  43 static spinlock_t wdt_lock;
  44
  45 static void orion5x_wdt_ping(void)
  46 {
  47         spin_lock(&wdt_lock);
  48
  49         /* Reload watchdog duration */
  50         writel(wdt_tclk * heartbeat, WDT_VAL);
  51
  52         spin_unlock(&wdt_lock);
  53 }
  54
  55 static void orion5x_wdt_enable(void)
  56 {
  57         u32 reg;
  58
  59         spin_lock(&wdt_lock);
  60
  61         /* Set watchdog duration */
  62         writel(wdt_tclk * heartbeat, WDT_VAL);
  63
  64         /* Clear watchdog timer interrupt */
  65         reg = readl(BRIDGE_CAUSE);
  66         reg &= ~WDT_INT_REQ;
  67         writel(reg, BRIDGE_CAUSE);
  68
  69         /* Enable watchdog timer */
  70         reg = readl(TIMER_CTRL);
  71         reg |= WDT_EN;
  72         writel(reg, TIMER_CTRL);
  73
  74         /* Enable reset on watchdog */
  75         reg = readl(CPU_RESET_MASK);
  76         reg |= WDT_RESET;
  77         writel(reg, CPU_RESET_MASK);
  78
  79         spin_unlock(&wdt_lock);
  80 }
  81
  82 static void orion5x_wdt_disable(void)
  83 {
  84         u32 reg;
  85
  86         spin_lock(&wdt_lock);
  87
  88         /* Disable reset on watchdog */
  89         reg = readl(CPU_RESET_MASK);
  90         reg &= ~WDT_RESET;
  91         writel(reg, CPU_RESET_MASK);
  92
  93         /* Disable watchdog timer */
  94         reg = readl(TIMER_CTRL);
  95         reg &= ~WDT_EN;
  96         writel(reg, TIMER_CTRL);
  97
  98         spin_unlock(&wdt_lock);
  99 }
 100
 101 static int orion5x_wdt_get_timeleft(int *time_left)
 102 {
 103         spin_lock(&wdt_lock);
 104         *time_left = readl(WDT_VAL) / wdt_tclk;
 105         spin_unlock(&wdt_lock);
 106         return 0;
 107 }
 108
 109 static int orion5x_wdt_open(struct inode *inode, struct file *file)
 110 {
 111         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
 112                 return -EBUSY;
 113         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 114         orion5x_wdt_enable();
 115         return nonseekable_open(inode, file);
 116 }
 117
 118 static ssize_t orion5x_wdt_write(struct file *file, const char *data,
 119                                         size_t len, loff_t *ppos)
 120 {
 121         if (len) {
 122                 if (!nowayout) {
 123                         size_t i;
 124
 125                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 126                         for (i = 0; i != len; i++) {
 127                                 char c;
 128
 129                                 if (get_user(c, data + i))
 130                                         return -EFAULT;
 131                                 if (c == 'V')
 132                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
 133                         }
 134                 }
 135                 orion5x_wdt_ping();
 136         }
 137         return len;
 138 }
 139
 140 static int orion5x_wdt_settimeout(int new_time)
 141 {
 142         if ((new_time <= 0) || (new_time > wdt_max_duration))
 143                 return -EINVAL;
 144
 145         /* Set new watchdog time to be used when
 146          * orion5x_wdt_enable() or orion5x_wdt_ping() is called. */
 147         heartbeat = new_time;
 148         return 0;
 149 }
 150
 151 static const struct watchdog_info ident = {
 152         .options        = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
 153                           WDIOF_KEEPALIVEPING,
 154         .identity       = "Orion5x Watchdog",
 155 };
 156
 157 static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
 158                                 unsigned long arg)
 159 {
 160         int ret = -ENOTTY;
 161         int time;
 162
 163         switch (cmd) {
 164         case WDIOC_GETSUPPORT:
 165                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
 166                                    sizeof(ident)) ? -EFAULT : 0;
 167                 break;
 168
 169         case WDIOC_GETSTATUS:
 170         case WDIOC_GETBOOTSTATUS:
 171                 ret = put_user(0, (int *)arg);
 172                 break;
 173
 174         case WDIOC_KEEPALIVE:
 175                 orion5x_wdt_ping();
 176                 ret = 0;
 177                 break;
 178
 179         case WDIOC_SETTIMEOUT:
 180                 ret = get_user(time, (int *)arg);
 181                 if (ret)
 182                         break;
 183
 184                 if (orion5x_wdt_settimeout(time)) {
 185                         ret = -EINVAL;
 186                         break;
 187                 }
 188                 orion5x_wdt_ping();
 189                 /* Fall through */
 190
 191         case WDIOC_GETTIMEOUT:
 192                 ret = put_user(heartbeat, (int *)arg);
 193                 break;
 194
 195         case WDIOC_GETTIMELEFT:
 196                 if (orion5x_wdt_get_timeleft(&time)) {
 197                         ret = -EINVAL;
 198                         break;
 199                 }
 200                 ret = put_user(time, (int *)arg);
 201                 break;
 202         }
 203         return ret;
 204 }
 205
 206 static int orion5x_wdt_release(struct inode *inode, struct file *file)
 207 {
 208         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
 209                 orion5x_wdt_disable();
 210         else
 211                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
 212                                         "timer will not stop\n");
 213         clear_bit(WDT_IN_USE, &wdt_status);
 214         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 215
 216         return 0;
 217 }
 218
 219
 220 static const struct file_operations orion5x_wdt_fops = {
 221         .owner          = THIS_MODULE,
 222         .llseek         = no_llseek,
 223         .write          = orion5x_wdt_write,
 224         .unlocked_ioctl = orion5x_wdt_ioctl,
 225         .open           = orion5x_wdt_open,
 226         .release        = orion5x_wdt_release,
 227 };
 228
 229 static struct miscdevice orion5x_wdt_miscdev = {
 230         .minor          = WATCHDOG_MINOR,
 231         .name           = "watchdog",
 232         .fops           = &orion5x_wdt_fops,
 233 };
 234
 235 static int __devinit orion5x_wdt_probe(struct platform_device *pdev)
 236 {
 237         struct orion5x_wdt_platform_data *pdata = pdev->dev.platform_data;
 238         int ret;
 239
 240         if (pdata) {
 241                 wdt_tclk = pdata->tclk;
 242         } else {
 243                 printk(KERN_ERR "Orion5x Watchdog misses platform data\n");
 244                 return -ENODEV;
 245         }
 246
 247         if (orion5x_wdt_miscdev.parent)
 248                 return -EBUSY;
 249         orion5x_wdt_miscdev.parent = &pdev->dev;
 250
 251         wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
 252         if (orion5x_wdt_settimeout(heartbeat))
 253                 heartbeat = wdt_max_duration;
 254
 255         ret = misc_register(&orion5x_wdt_miscdev);
 256         if (ret)
 257                 return ret;
 258
 259         printk(KERN_INFO "Orion5x Watchdog Timer: Initial timeout %d sec%s\n",
 260                                 heartbeat, nowayout ? ", nowayout" : "");
 261         return 0;
 262 }
 263
 264 static int __devexit orion5x_wdt_remove(struct platform_device *pdev)
 265 {
 266         int ret;
 267
 268         if (test_bit(WDT_IN_USE, &wdt_status)) {
 269                 orion5x_wdt_disable();
 270                 clear_bit(WDT_IN_USE, &wdt_status);
 271         }
 272
 273         ret = misc_deregister(&orion5x_wdt_miscdev);
 274         if (!ret)
 275                 orion5x_wdt_miscdev.parent = NULL;
 276
 277         return ret;
 278 }
 279
 280 static void orion5x_wdt_shutdown(struct platform_device *pdev)
 281 {
 282         if (test_bit(WDT_IN_USE, &wdt_status))
 283                 orion5x_wdt_disable();
 284 }
 285
 286 static struct platform_driver orion5x_wdt_driver = {
 287         .probe          = orion5x_wdt_probe,
 288         .remove         = __devexit_p(orion5x_wdt_remove),
 289         .shutdown       = orion5x_wdt_shutdown,
 290         .driver         = {
 291                 .owner  = THIS_MODULE,
 292                 .name   = "orion5x_wdt",
 293         },
 294 };
 295
 296 static int __init orion5x_wdt_init(void)
 297 {
 298         spin_lock_init(&wdt_lock);
 299         return platform_driver_register(&orion5x_wdt_driver);
 300 }
 301
 302 static void __exit orion5x_wdt_exit(void)
 303 {
 304         platform_driver_unregister(&orion5x_wdt_driver);
 305 }
 306
 307 module_init(orion5x_wdt_init);
 308 module_exit(orion5x_wdt_exit);
 309
 310 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
 311 MODULE_DESCRIPTION("Orion5x Processor Watchdog");
 312
 313 module_param(heartbeat, int, 0);
 314 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
 315
 316 module_param(nowayout, int, 0);
 317 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 318                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 319
 320 MODULE_LICENSE("GPL");
 321 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);