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