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