drivers/watchdog/stmp3xxx_wdt.c

   1 /*
   2  * Watchdog driver for Freescale STMP37XX/STMP378X
   3  *
   4  * Author: Vitaly Wool <vital@embeddedalley.com>
   5  *
   6  * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
   7  * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
   8  */
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/fs.h>
  12 #include <linux/miscdevice.h>
  13 #include <linux/watchdog.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/uaccess.h>
  17 #include <linux/module.h>
  18
  19 #include <mach/platform.h>
  20 #include <mach/regs-rtc.h>
  21
  22 #define DEFAULT_HEARTBEAT       19
  23 #define MAX_HEARTBEAT           (0x10000000 >> 6)
  24
  25 /* missing bitmask in headers */
  26 #define BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER     0x80000000
  27
  28 #define WDT_IN_USE              0
  29 #define WDT_OK_TO_CLOSE         1
  30
  31 #define WDOG_COUNTER_RATE       1000 /* 1 kHz clock */
  32
  33 static DEFINE_SPINLOCK(stmp3xxx_wdt_io_lock);
  34 static unsigned long wdt_status;
  35 static const int nowayout = WATCHDOG_NOWAYOUT;
  36 static int heartbeat = DEFAULT_HEARTBEAT;
  37 static unsigned long boot_status;
  38
  39 static void wdt_enable(u32 value)
  40 {
  41         spin_lock(&stmp3xxx_wdt_io_lock);
  42         __raw_writel(value, REGS_RTC_BASE + HW_RTC_WATCHDOG);
  43         stmp3xxx_setl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
  44         stmp3xxx_setl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
  45                         REGS_RTC_BASE + HW_RTC_PERSISTENT1);
  46         spin_unlock(&stmp3xxx_wdt_io_lock);
  47 }
  48
  49 static void wdt_disable(void)
  50 {
  51         spin_lock(&stmp3xxx_wdt_io_lock);
  52         stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
  53                         REGS_RTC_BASE + HW_RTC_PERSISTENT1);
  54         stmp3xxx_clearl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
  55         spin_unlock(&stmp3xxx_wdt_io_lock);
  56 }
  57
  58 static void wdt_ping(void)
  59 {
  60         wdt_enable(heartbeat * WDOG_COUNTER_RATE);
  61 }
  62
  63 static int stmp3xxx_wdt_open(struct inode *inode, struct file *file)
  64 {
  65         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
  66                 return -EBUSY;
  67
  68         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
  69         wdt_ping();
  70
  71         return nonseekable_open(inode, file);
  72 }
  73
  74 static ssize_t stmp3xxx_wdt_write(struct file *file, const char __user *data,
  75         size_t len, loff_t *ppos)
  76 {
  77         if (len) {
  78                 if (!nowayout) {
  79                         size_t i;
  80
  81                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
  82
  83                         for (i = 0; i != len; i++) {
  84                                 char c;
  85
  86                                 if (get_user(c, data + i))
  87                                         return -EFAULT;
  88                                 if (c == 'V')
  89                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
  90                         }
  91                 }
  92                 wdt_ping();
  93         }
  94
  95         return len;
  96 }
  97
  98 static const struct watchdog_info ident = {
  99         .options        = WDIOF_CARDRESET |
 100                           WDIOF_MAGICCLOSE |
 101                           WDIOF_SETTIMEOUT |
 102                           WDIOF_KEEPALIVEPING,
 103         .identity       = "STMP3XXX Watchdog",
 104 };
 105
 106 static long stmp3xxx_wdt_ioctl(struct file *file, unsigned int cmd,
 107         unsigned long arg)
 108 {
 109         void __user *argp = (void __user *)arg;
 110         int __user *p = argp;
 111         int new_heartbeat, opts;
 112         int ret = -ENOTTY;
 113
 114         switch (cmd) {
 115         case WDIOC_GETSUPPORT:
 116                 ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 117                 break;
 118
 119         case WDIOC_GETSTATUS:
 120                 ret = put_user(0, p);
 121                 break;
 122
 123         case WDIOC_GETBOOTSTATUS:
 124                 ret = put_user(boot_status, p);
 125                 break;
 126
 127         case WDIOC_SETOPTIONS:
 128                 if (get_user(opts, p)) {
 129                         ret = -EFAULT;
 130                         break;
 131                 }
 132                 if (opts & WDIOS_DISABLECARD)
 133                         wdt_disable();
 134                 else if (opts & WDIOS_ENABLECARD)
 135                         wdt_ping();
 136                 else {
 137                         pr_debug("%s: unknown option 0x%x\n", __func__, opts);
 138                         ret = -EINVAL;
 139                         break;
 140                 }
 141                 ret = 0;
 142                 break;
 143
 144         case WDIOC_KEEPALIVE:
 145                 wdt_ping();
 146                 ret = 0;
 147                 break;
 148
 149         case WDIOC_SETTIMEOUT:
 150                 if (get_user(new_heartbeat, p)) {
 151                         ret = -EFAULT;
 152                         break;
 153                 }
 154                 if (new_heartbeat <= 0 || new_heartbeat > MAX_HEARTBEAT) {
 155                         ret = -EINVAL;
 156                         break;
 157                 }
 158
 159                 heartbeat = new_heartbeat;
 160                 wdt_ping();
 161                 /* Fall through */
 162
 163         case WDIOC_GETTIMEOUT:
 164                 ret = put_user(heartbeat, p);
 165                 break;
 166         }
 167         return ret;
 168 }
 169
 170 static int stmp3xxx_wdt_release(struct inode *inode, struct file *file)
 171 {
 172         int ret = 0;
 173
 174         if (!nowayout) {
 175                 if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
 176                         wdt_ping();
 177                         pr_debug("%s: Device closed unexpectedly\n", __func__);
 178                         ret = -EINVAL;
 179                 } else {
 180                         wdt_disable();
 181                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 182                 }
 183         }
 184         clear_bit(WDT_IN_USE, &wdt_status);
 185
 186         return ret;
 187 }
 188
 189 static const struct file_operations stmp3xxx_wdt_fops = {
 190         .owner = THIS_MODULE,
 191         .llseek = no_llseek,
 192         .write = stmp3xxx_wdt_write,
 193         .unlocked_ioctl = stmp3xxx_wdt_ioctl,
 194         .open = stmp3xxx_wdt_open,
 195         .release = stmp3xxx_wdt_release,
 196 };
 197
 198 static struct miscdevice stmp3xxx_wdt_miscdev = {
 199         .minor = WATCHDOG_MINOR,
 200         .name = "watchdog",
 201         .fops = &stmp3xxx_wdt_fops,
 202 };
 203
 204 static int __devinit stmp3xxx_wdt_probe(struct platform_device *pdev)
 205 {
 206         int ret = 0;
 207
 208         if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
 209                 heartbeat = DEFAULT_HEARTBEAT;
 210
 211         boot_status = __raw_readl(REGS_RTC_BASE + HW_RTC_PERSISTENT1) &
 212                         BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER;
 213         boot_status = !!boot_status;
 214         stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
 215                         REGS_RTC_BASE + HW_RTC_PERSISTENT1);
 216         wdt_disable();          /* disable for now */
 217
 218         ret = misc_register(&stmp3xxx_wdt_miscdev);
 219         if (ret < 0) {
 220                 dev_err(&pdev->dev, "cannot register misc device\n");
 221                 return ret;
 222         }
 223
 224         printk(KERN_INFO "stmp3xxx watchdog: initialized, heartbeat %d sec\n",
 225                 heartbeat);
 226
 227         return ret;
 228 }
 229
 230 static int __devexit stmp3xxx_wdt_remove(struct platform_device *pdev)
 231 {
 232         misc_deregister(&stmp3xxx_wdt_miscdev);
 233         return 0;
 234 }
 235
 236 #ifdef CONFIG_PM
 237 static int wdt_suspended;
 238 static u32 wdt_saved_time;
 239
 240 static int stmp3xxx_wdt_suspend(struct platform_device *pdev,
 241                                 pm_message_t state)
 242 {
 243         if (__raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) &
 244                 BM_RTC_CTRL_WATCHDOGEN) {
 245                 wdt_suspended = 1;
 246                 wdt_saved_time = __raw_readl(REGS_RTC_BASE + HW_RTC_WATCHDOG);
 247                 wdt_disable();
 248         }
 249         return 0;
 250 }
 251
 252 static int stmp3xxx_wdt_resume(struct platform_device *pdev)
 253 {
 254         if (wdt_suspended) {
 255                 wdt_enable(wdt_saved_time);
 256                 wdt_suspended = 0;
 257         }
 258         return 0;
 259 }
 260 #else
 261 #define stmp3xxx_wdt_suspend    NULL
 262 #define stmp3xxx_wdt_resume     NULL
 263 #endif
 264
 265 static struct platform_driver platform_wdt_driver = {
 266         .driver = {
 267                 .name = "stmp3xxx_wdt",
 268         },
 269         .probe = stmp3xxx_wdt_probe,
 270         .remove = __devexit_p(stmp3xxx_wdt_remove),
 271         .suspend = stmp3xxx_wdt_suspend,
 272         .resume = stmp3xxx_wdt_resume,
 273 };
 274
 275 module_platform_driver(platform_wdt_driver);
 276
 277 MODULE_DESCRIPTION("STMP3XXX Watchdog Driver");
 278 MODULE_LICENSE("GPL");
 279
 280 module_param(heartbeat, int, 0);
 281 MODULE_PARM_DESC(heartbeat,
 282                  "Watchdog heartbeat period in seconds from 1 to "
 283                  __MODULE_STRING(MAX_HEARTBEAT) ", default "
 284                  __MODULE_STRING(DEFAULT_HEARTBEAT));
 285
 286 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);