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
  18 #include <mach/platform.h>
  19 #include <mach/regs-rtc.h>
  20
  21 #define DEFAULT_HEARTBEAT       19
  22 #define MAX_HEARTBEAT           (0x10000000 >> 6)
  23
  24 /* missing bitmask in headers */
  25 #define BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER     0x80000000
  26
  27 #define WDT_IN_USE              0
  28 #define WDT_OK_TO_CLOSE         1
  29
  30 #define WDOG_COUNTER_RATE       1000 /* 1 kHz clock */
  31
  32 static DEFINE_SPINLOCK(stmp3xxx_wdt_io_lock);
  33 static unsigned long wdt_status;
  34 static const int nowayout = WATCHDOG_NOWAYOUT;
  35 static int heartbeat = DEFAULT_HEARTBEAT;
  36 static unsigned long boot_status;
  37
  38 static void wdt_enable(u32 value)
  39 {
  40         spin_lock(&stmp3xxx_wdt_io_lock);
  41         __raw_writel(value, REGS_RTC_BASE + HW_RTC_WATCHDOG);
  42         stmp3xxx_setl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
  43         stmp3xxx_setl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
  44                         REGS_RTC_BASE + HW_RTC_PERSISTENT1);
  45         spin_unlock(&stmp3xxx_wdt_io_lock);
  46 }
  47
  48 static void wdt_disable(void)
  49 {
  50         spin_lock(&stmp3xxx_wdt_io_lock);
  51         stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
  52                         REGS_RTC_BASE + HW_RTC_PERSISTENT1);
  53         stmp3xxx_clearl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
  54         spin_unlock(&stmp3xxx_wdt_io_lock);
  55 }
  56
  57 static void wdt_ping(void)
  58 {
  59         wdt_enable(heartbeat * WDOG_COUNTER_RATE);
  60 }
  61
  62 static int stmp3xxx_wdt_open(struct inode *inode, struct file *file)
  63 {
  64         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
  65                 return -EBUSY;
  66
  67         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
  68         wdt_ping();
  69
  70         return nonseekable_open(inode, file);
  71 }
  72
  73 static ssize_t stmp3xxx_wdt_write(struct file *file, const char __user *data,
  74         size_t len, loff_t *ppos)
  75 {
  76         if (len) {
  77                 if (!nowayout) {
  78                         size_t i;
  79
  80                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
  81
  82                         for (i = 0; i != len; i++) {
  83                                 char c;
  84
  85                                 if (get_user(c, data + i))
  86                                         return -EFAULT;
  87                                 if (c == 'V')
  88                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
  89                         }
  90                 }
  91                 wdt_ping();
  92         }
  93
  94         return len;
  95 }
  96
  97 static const struct watchdog_info ident = {
  98         .options        = WDIOF_CARDRESET |
  99                           WDIOF_MAGICCLOSE |
 100                           WDIOF_SETTIMEOUT |
 101                           WDIOF_KEEPALIVEPING,
 102         .identity       = "STMP3XXX Watchdog",
 103 };
 104
 105 static long stmp3xxx_wdt_ioctl(struct file *file, unsigned int cmd,
 106         unsigned long arg)
 107 {
 108         void __user *argp = (void __user *)arg;
 109         int __user *p = argp;
 110         int new_heartbeat, opts;
 111         int ret = -ENOTTY;
 112
 113         switch (cmd) {
 114         case WDIOC_GETSUPPORT:
 115                 ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 116                 break;
 117
 118         case WDIOC_GETSTATUS:
 119                 ret = put_user(0, p);
 120                 break;
 121
 122         case WDIOC_GETBOOTSTATUS:
 123                 ret = put_user(boot_status, p);
 124                 break;
 125
 126         case WDIOC_SETOPTIONS:
 127                 if (get_user(opts, p)) {
 128                         ret = -EFAULT;
 129                         break;
 130                 }
 131                 if (opts & WDIOS_DISABLECARD)
 132                         wdt_disable();
 133                 else if (opts & WDIOS_ENABLECARD)
 134                         wdt_ping();
 135                 else {
 136                         pr_debug("%s: unknown option 0x%x\n", __func__, opts);
 137                         ret = -EINVAL;
 138                         break;
 139                 }
 140                 ret = 0;
 141                 break;
 142
 143         case WDIOC_KEEPALIVE:
 144                 wdt_ping();
 145                 ret = 0;
 146                 break;
 147
 148         case WDIOC_SETTIMEOUT:
 149                 if (get_user(new_heartbeat, p)) {
 150                         ret = -EFAULT;
 151                         break;
 152                 }
 153                 if (new_heartbeat <= 0 || new_heartbeat > MAX_HEARTBEAT) {
 154                         ret = -EINVAL;
 155                         break;
 156                 }
 157
 158                 heartbeat = new_heartbeat;
 159                 wdt_ping();
 160                 /* Fall through */
 161
 162         case WDIOC_GETTIMEOUT:
 163                 ret = put_user(heartbeat, p);
 164                 break;
 165         }
 166         return ret;
 167 }
 168
 169 static int stmp3xxx_wdt_release(struct inode *inode, struct file *file)
 170 {
 171         int ret = 0;
 172
 173         if (!nowayout) {
 174                 if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
 175                         wdt_ping();
 176                         pr_debug("%s: Device closed unexpectdly\n", __func__);
 177                         ret = -EINVAL;
 178                 } else {
 179                         wdt_disable();
 180                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 181                 }
 182         }
 183         clear_bit(WDT_IN_USE, &wdt_status);
 184
 185         return ret;
 186 }
 187
 188 static const struct file_operations stmp3xxx_wdt_fops = {
 189         .owner = THIS_MODULE,
 190         .llseek = no_llseek,
 191         .write = stmp3xxx_wdt_write,
 192         .unlocked_ioctl = stmp3xxx_wdt_ioctl,
 193         .open = stmp3xxx_wdt_open,
 194         .release = stmp3xxx_wdt_release,
 195 };
 196
 197 static struct miscdevice stmp3xxx_wdt_miscdev = {
 198         .minor = WATCHDOG_MINOR,
 199         .name = "watchdog",
 200         .fops = &stmp3xxx_wdt_fops,
 201 };
 202
 203 static int __devinit stmp3xxx_wdt_probe(struct platform_device *pdev)
 204 {
 205         int ret = 0;
 206
 207         if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
 208                 heartbeat = DEFAULT_HEARTBEAT;
 209
 210         boot_status = __raw_readl(REGS_RTC_BASE + HW_RTC_PERSISTENT1) &
 211                         BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER;
 212         boot_status = !!boot_status;
 213         stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
 214                         REGS_RTC_BASE + HW_RTC_PERSISTENT1);
 215         wdt_disable();          /* disable for now */
 216
 217         ret = misc_register(&stmp3xxx_wdt_miscdev);
 218         if (ret < 0) {
 219                 dev_err(&pdev->dev, "cannot register misc device\n");
 220                 return ret;
 221         }
 222
 223         printk(KERN_INFO "stmp3xxx watchdog: initialized, heartbeat %d sec\n",
 224                 heartbeat);
 225
 226         return ret;
 227 }
 228
 229 static int __devexit stmp3xxx_wdt_remove(struct platform_device *pdev)
 230 {
 231         misc_deregister(&stmp3xxx_wdt_miscdev);
 232         return 0;
 233 }
 234
 235 #ifdef CONFIG_PM
 236 static int wdt_suspended;
 237 static u32 wdt_saved_time;
 238
 239 static int stmp3xxx_wdt_suspend(struct platform_device *pdev,
 240                                 pm_message_t state)
 241 {
 242         if (__raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) &
 243                 BM_RTC_CTRL_WATCHDOGEN) {
 244                 wdt_suspended = 1;
 245                 wdt_saved_time = __raw_readl(REGS_RTC_BASE + HW_RTC_WATCHDOG);
 246                 wdt_disable();
 247         }
 248         return 0;
 249 }
 250
 251 static int stmp3xxx_wdt_resume(struct platform_device *pdev)
 252 {
 253         if (wdt_suspended) {
 254                 wdt_enable(wdt_saved_time);
 255                 wdt_suspended = 0;
 256         }
 257         return 0;
 258 }
 259 #else
 260 #define stmp3xxx_wdt_suspend    NULL
 261 #define stmp3xxx_wdt_resume     NULL
 262 #endif
 263
 264 static struct platform_driver platform_wdt_driver = {
 265         .driver = {
 266                 .name = "stmp3xxx_wdt",
 267         },
 268         .probe = stmp3xxx_wdt_probe,
 269         .remove = __devexit_p(stmp3xxx_wdt_remove),
 270         .suspend = stmp3xxx_wdt_suspend,
 271         .resume = stmp3xxx_wdt_resume,
 272 };
 273
 274 static int __init stmp3xxx_wdt_init(void)
 275 {
 276         return platform_driver_register(&platform_wdt_driver);
 277 }
 278
 279 static void __exit stmp3xxx_wdt_exit(void)
 280 {
 281         return platform_driver_unregister(&platform_wdt_driver);
 282 }
 283
 284 module_init(stmp3xxx_wdt_init);
 285 module_exit(stmp3xxx_wdt_exit);
 286
 287 MODULE_DESCRIPTION("STMP3XXX Watchdog Driver");
 288 MODULE_LICENSE("GPL");
 289
 290 module_param(heartbeat, int, 0);
 291 MODULE_PARM_DESC(heartbeat,
 292                  "Watchdog heartbeat period in seconds from 1 to "
 293                  __MODULE_STRING(MAX_HEARTBEAT) ", default "
 294                  __MODULE_STRING(DEFAULT_HEARTBEAT));
 295
 296 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);