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 <linux/clk.h>
  28 #include <linux/of.h>
  29 #include <mach/bridge-regs.h>
  30
  31 /*
  32  * Watchdog timer block registers.
  33  */
  34 #define TIMER_CTRL              0x0000
  35 #define  WDT_EN                 0x0010
  36 #define WDT_VAL                 0x0024
  37
  38 #define WDT_MAX_CYCLE_COUNT     0xffffffff
  39 #define WDT_IN_USE              0
  40 #define WDT_OK_TO_CLOSE         1
  41
  42 static bool nowayout = WATCHDOG_NOWAYOUT;
  43 static int heartbeat = -1;              /* module parameter (seconds) */
  44 static unsigned int wdt_max_duration;   /* (seconds) */
  45 static struct clk *clk;
  46 static unsigned int wdt_tclk;
  47 static void __iomem *wdt_reg;
  48 static unsigned long wdt_status;
  49 static DEFINE_SPINLOCK(wdt_lock);
  50
  51 static void orion_wdt_ping(void)
  52 {
  53         spin_lock(&wdt_lock);
  54
  55         /* Reload watchdog duration */
  56         writel(wdt_tclk * heartbeat, wdt_reg + WDT_VAL);
  57
  58         spin_unlock(&wdt_lock);
  59 }
  60
  61 static void orion_wdt_enable(void)
  62 {
  63         u32 reg;
  64
  65         spin_lock(&wdt_lock);
  66
  67         /* Set watchdog duration */
  68         writel(wdt_tclk * heartbeat, wdt_reg + WDT_VAL);
  69
  70         /* Clear watchdog timer interrupt */
  71         reg = readl(BRIDGE_CAUSE);
  72         reg &= ~WDT_INT_REQ;
  73         writel(reg, BRIDGE_CAUSE);
  74
  75         /* Enable watchdog timer */
  76         reg = readl(wdt_reg + TIMER_CTRL);
  77         reg |= WDT_EN;
  78         writel(reg, wdt_reg + TIMER_CTRL);
  79
  80         /* Enable reset on watchdog */
  81         reg = readl(RSTOUTn_MASK);
  82         reg |= WDT_RESET_OUT_EN;
  83         writel(reg, RSTOUTn_MASK);
  84
  85         spin_unlock(&wdt_lock);
  86 }
  87
  88 static void orion_wdt_disable(void)
  89 {
  90         u32 reg;
  91
  92         spin_lock(&wdt_lock);
  93
  94         /* Disable reset on watchdog */
  95         reg = readl(RSTOUTn_MASK);
  96         reg &= ~WDT_RESET_OUT_EN;
  97         writel(reg, RSTOUTn_MASK);
  98
  99         /* Disable watchdog timer */
 100         reg = readl(wdt_reg + TIMER_CTRL);
 101         reg &= ~WDT_EN;
 102         writel(reg, wdt_reg + TIMER_CTRL);
 103
 104         spin_unlock(&wdt_lock);
 105 }
 106
 107 static int orion_wdt_get_timeleft(int *time_left)
 108 {
 109         spin_lock(&wdt_lock);
 110         *time_left = readl(wdt_reg + WDT_VAL) / wdt_tclk;
 111         spin_unlock(&wdt_lock);
 112         return 0;
 113 }
 114
 115 static int orion_wdt_open(struct inode *inode, struct file *file)
 116 {
 117         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
 118                 return -EBUSY;
 119         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 120         orion_wdt_enable();
 121         return nonseekable_open(inode, file);
 122 }
 123
 124 static ssize_t orion_wdt_write(struct file *file, const char *data,
 125                                         size_t len, loff_t *ppos)
 126 {
 127         if (len) {
 128                 if (!nowayout) {
 129                         size_t i;
 130
 131                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 132                         for (i = 0; i != len; i++) {
 133                                 char c;
 134
 135                                 if (get_user(c, data + i))
 136                                         return -EFAULT;
 137                                 if (c == 'V')
 138                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
 139                         }
 140                 }
 141                 orion_wdt_ping();
 142         }
 143         return len;
 144 }
 145
 146 static int orion_wdt_settimeout(int new_time)
 147 {
 148         if ((new_time <= 0) || (new_time > wdt_max_duration))
 149                 return -EINVAL;
 150
 151         /* Set new watchdog time to be used when
 152          * orion_wdt_enable() or orion_wdt_ping() is called. */
 153         heartbeat = new_time;
 154         return 0;
 155 }
 156
 157 static const struct watchdog_info ident = {
 158         .options        = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
 159                           WDIOF_KEEPALIVEPING,
 160         .identity       = "Orion Watchdog",
 161 };
 162
 163 static long orion_wdt_ioctl(struct file *file, unsigned int cmd,
 164                                 unsigned long arg)
 165 {
 166         int ret = -ENOTTY;
 167         int time;
 168
 169         switch (cmd) {
 170         case WDIOC_GETSUPPORT:
 171                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
 172                                    sizeof(ident)) ? -EFAULT : 0;
 173                 break;
 174
 175         case WDIOC_GETSTATUS:
 176         case WDIOC_GETBOOTSTATUS:
 177                 ret = put_user(0, (int *)arg);
 178                 break;
 179
 180         case WDIOC_KEEPALIVE:
 181                 orion_wdt_ping();
 182                 ret = 0;
 183                 break;
 184
 185         case WDIOC_SETTIMEOUT:
 186                 ret = get_user(time, (int *)arg);
 187                 if (ret)
 188                         break;
 189
 190                 if (orion_wdt_settimeout(time)) {
 191                         ret = -EINVAL;
 192                         break;
 193                 }
 194                 orion_wdt_ping();
 195                 /* Fall through */
 196
 197         case WDIOC_GETTIMEOUT:
 198                 ret = put_user(heartbeat, (int *)arg);
 199                 break;
 200
 201         case WDIOC_GETTIMELEFT:
 202                 if (orion_wdt_get_timeleft(&time)) {
 203                         ret = -EINVAL;
 204                         break;
 205                 }
 206                 ret = put_user(time, (int *)arg);
 207                 break;
 208         }
 209         return ret;
 210 }
 211
 212 static int orion_wdt_release(struct inode *inode, struct file *file)
 213 {
 214         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
 215                 orion_wdt_disable();
 216         else
 217                 pr_crit("Device closed unexpectedly - timer will not stop\n");
 218         clear_bit(WDT_IN_USE, &wdt_status);
 219         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 220
 221         return 0;
 222 }
 223
 224
 225 static const struct file_operations orion_wdt_fops = {
 226         .owner          = THIS_MODULE,
 227         .llseek         = no_llseek,
 228         .write          = orion_wdt_write,
 229         .unlocked_ioctl = orion_wdt_ioctl,
 230         .open           = orion_wdt_open,
 231         .release        = orion_wdt_release,
 232 };
 233
 234 static struct miscdevice orion_wdt_miscdev = {
 235         .minor          = WATCHDOG_MINOR,
 236         .name           = "watchdog",
 237         .fops           = &orion_wdt_fops,
 238 };
 239
 240 static int __devinit orion_wdt_probe(struct platform_device *pdev)
 241 {
 242         struct resource *res;
 243         int ret;
 244
 245         clk = clk_get(&pdev->dev, NULL);
 246         if (IS_ERR(clk)) {
 247                 printk(KERN_ERR "Orion Watchdog missing clock\n");
 248                 return -ENODEV;
 249         }
 250         clk_prepare_enable(clk);
 251         wdt_tclk = clk_get_rate(clk);
 252
 253         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 254
 255         wdt_reg = ioremap(res->start, resource_size(res));
 256
 257         if (orion_wdt_miscdev.parent)
 258                 return -EBUSY;
 259         orion_wdt_miscdev.parent = &pdev->dev;
 260
 261         wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
 262         if (orion_wdt_settimeout(heartbeat))
 263                 heartbeat = wdt_max_duration;
 264
 265         ret = misc_register(&orion_wdt_miscdev);
 266         if (ret)
 267                 return ret;
 268
 269         pr_info("Initial timeout %d sec%s\n",
 270                 heartbeat, nowayout ? ", nowayout" : "");
 271         return 0;
 272 }
 273
 274 static int __devexit orion_wdt_remove(struct platform_device *pdev)
 275 {
 276         int ret;
 277
 278         if (test_bit(WDT_IN_USE, &wdt_status)) {
 279                 orion_wdt_disable();
 280                 clear_bit(WDT_IN_USE, &wdt_status);
 281         }
 282
 283         ret = misc_deregister(&orion_wdt_miscdev);
 284         if (!ret)
 285                 orion_wdt_miscdev.parent = NULL;
 286
 287         clk_disable_unprepare(clk);
 288         clk_put(clk);
 289
 290         return ret;
 291 }
 292
 293 static void orion_wdt_shutdown(struct platform_device *pdev)
 294 {
 295         if (test_bit(WDT_IN_USE, &wdt_status))
 296                 orion_wdt_disable();
 297 }
 298
 299 static const struct of_device_id orion_wdt_of_match_table[] __devinitdata = {
 300         { .compatible = "marvell,orion-wdt", },
 301         {},
 302 };
 303 MODULE_DEVICE_TABLE(of, orion_wdt_of_match_table);
 304
 305 static struct platform_driver orion_wdt_driver = {
 306         .probe          = orion_wdt_probe,
 307         .remove         = __devexit_p(orion_wdt_remove),
 308         .shutdown       = orion_wdt_shutdown,
 309         .driver         = {
 310                 .owner  = THIS_MODULE,
 311                 .name   = "orion_wdt",
 312                 .of_match_table = of_match_ptr(orion_wdt_of_match_table),
 313         },
 314 };
 315
 316 module_platform_driver(orion_wdt_driver);
 317
 318 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
 319 MODULE_DESCRIPTION("Orion Processor Watchdog");
 320
 321 module_param(heartbeat, int, 0);
 322 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
 323
 324 module_param(nowayout, bool, 0);
 325 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 326                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 327
 328 MODULE_LICENSE("GPL");
 329 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);