drivers/watchdog/rdc321x_wdt.c

   1 /*
   2  * RDC321x watchdog driver
   3  *
   4  * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
   5  *
   6  * This driver is highly inspired from the cpu5_wdt driver
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  *
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/types.h>
  27 #include <linux/errno.h>
  28 #include <linux/miscdevice.h>
  29 #include <linux/fs.h>
  30 #include <linux/init.h>
  31 #include <linux/ioport.h>
  32 #include <linux/timer.h>
  33 #include <linux/completion.h>
  34 #include <linux/jiffies.h>
  35 #include <linux/platform_device.h>
  36 #include <linux/watchdog.h>
  37 #include <linux/io.h>
  38 #include <linux/uaccess.h>
  39 #include <linux/mfd/rdc321x.h>
  40 #include <linux/mfd/core.h>
  41
  42 #define RDC_WDT_MASK    0x80000000 /* Mask */
  43 #define RDC_WDT_EN      0x00800000 /* Enable bit */
  44 #define RDC_WDT_WTI     0x00200000 /* Generate CPU reset/NMI/WDT on timeout */
  45 #define RDC_WDT_RST     0x00100000 /* Reset bit */
  46 #define RDC_WDT_WIF     0x00040000 /* WDT IRQ Flag */
  47 #define RDC_WDT_IRT     0x00000100 /* IRQ Routing table */
  48 #define RDC_WDT_CNT     0x00000001 /* WDT count */
  49
  50 #define RDC_CLS_TMR     0x80003844 /* Clear timer */
  51
  52 #define RDC_WDT_INTERVAL        (HZ/10+1)
  53
  54 static int ticks = 1000;
  55
  56 /* some device data */
  57
  58 static struct {
  59         struct completion stop;
  60         int running;
  61         struct timer_list timer;
  62         int queue;
  63         int default_ticks;
  64         unsigned long inuse;
  65         spinlock_t lock;
  66         struct pci_dev *sb_pdev;
  67         int base_reg;
  68 } rdc321x_wdt_device;
  69
  70 /* generic helper functions */
  71
  72 static void rdc321x_wdt_trigger(unsigned long unused)
  73 {
  74         unsigned long flags;
  75         u32 val;
  76
  77         if (rdc321x_wdt_device.running)
  78                 ticks--;
  79
  80         /* keep watchdog alive */
  81         spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
  82         pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
  83                                         rdc321x_wdt_device.base_reg, &val);
  84         val |= RDC_WDT_EN;
  85         pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
  86                                         rdc321x_wdt_device.base_reg, val);
  87         spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
  88
  89         /* requeue?? */
  90         if (rdc321x_wdt_device.queue && ticks)
  91                 mod_timer(&rdc321x_wdt_device.timer,
  92                                 jiffies + RDC_WDT_INTERVAL);
  93         else {
  94                 /* ticks doesn't matter anyway */
  95                 complete(&rdc321x_wdt_device.stop);
  96         }
  97
  98 }
  99
 100 static void rdc321x_wdt_reset(void)
 101 {
 102         ticks = rdc321x_wdt_device.default_ticks;
 103 }
 104
 105 static void rdc321x_wdt_start(void)
 106 {
 107         unsigned long flags;
 108
 109         if (!rdc321x_wdt_device.queue) {
 110                 rdc321x_wdt_device.queue = 1;
 111
 112                 /* Clear the timer */
 113                 spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
 114                 pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
 115                                 rdc321x_wdt_device.base_reg, RDC_CLS_TMR);
 116
 117                 /* Enable watchdog and set the timeout to 81.92 us */
 118                 pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
 119                                         rdc321x_wdt_device.base_reg,
 120                                         RDC_WDT_EN | RDC_WDT_CNT);
 121                 spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
 122
 123                 mod_timer(&rdc321x_wdt_device.timer,
 124                                 jiffies + RDC_WDT_INTERVAL);
 125         }
 126
 127         /* if process dies, counter is not decremented */
 128         rdc321x_wdt_device.running++;
 129 }
 130
 131 static int rdc321x_wdt_stop(void)
 132 {
 133         if (rdc321x_wdt_device.running)
 134                 rdc321x_wdt_device.running = 0;
 135
 136         ticks = rdc321x_wdt_device.default_ticks;
 137
 138         return -EIO;
 139 }
 140
 141 /* filesystem operations */
 142 static int rdc321x_wdt_open(struct inode *inode, struct file *file)
 143 {
 144         if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
 145                 return -EBUSY;
 146
 147         return nonseekable_open(inode, file);
 148 }
 149
 150 static int rdc321x_wdt_release(struct inode *inode, struct file *file)
 151 {
 152         clear_bit(0, &rdc321x_wdt_device.inuse);
 153         return 0;
 154 }
 155
 156 static long rdc321x_wdt_ioctl(struct file *file, unsigned int cmd,
 157                                 unsigned long arg)
 158 {
 159         void __user *argp = (void __user *)arg;
 160         u32 value;
 161         static const struct watchdog_info ident = {
 162                 .options = WDIOF_CARDRESET,
 163                 .identity = "RDC321x WDT",
 164         };
 165         unsigned long flags;
 166
 167         switch (cmd) {
 168         case WDIOC_KEEPALIVE:
 169                 rdc321x_wdt_reset();
 170                 break;
 171         case WDIOC_GETSTATUS:
 172                 /* Read the value from the DATA register */
 173                 spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
 174                 pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
 175                                         rdc321x_wdt_device.base_reg, &value);
 176                 spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
 177                 if (copy_to_user(argp, &value, sizeof(u32)))
 178                         return -EFAULT;
 179                 break;
 180         case WDIOC_GETSUPPORT:
 181                 if (copy_to_user(argp, &ident, sizeof(ident)))
 182                         return -EFAULT;
 183                 break;
 184         case WDIOC_SETOPTIONS:
 185                 if (copy_from_user(&value, argp, sizeof(int)))
 186                         return -EFAULT;
 187                 switch (value) {
 188                 case WDIOS_ENABLECARD:
 189                         rdc321x_wdt_start();
 190                         break;
 191                 case WDIOS_DISABLECARD:
 192                         return rdc321x_wdt_stop();
 193                 default:
 194                         return -EINVAL;
 195                 }
 196                 break;
 197         default:
 198                 return -ENOTTY;
 199         }
 200         return 0;
 201 }
 202
 203 static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf,
 204                                 size_t count, loff_t *ppos)
 205 {
 206         if (!count)
 207                 return -EIO;
 208
 209         rdc321x_wdt_reset();
 210
 211         return count;
 212 }
 213
 214 static const struct file_operations rdc321x_wdt_fops = {
 215         .owner          = THIS_MODULE,
 216         .llseek         = no_llseek,
 217         .unlocked_ioctl = rdc321x_wdt_ioctl,
 218         .open           = rdc321x_wdt_open,
 219         .write          = rdc321x_wdt_write,
 220         .release        = rdc321x_wdt_release,
 221 };
 222
 223 static struct miscdevice rdc321x_wdt_misc = {
 224         .minor  = WATCHDOG_MINOR,
 225         .name   = "watchdog",
 226         .fops   = &rdc321x_wdt_fops,
 227 };
 228
 229 static int __devinit rdc321x_wdt_probe(struct platform_device *pdev)
 230 {
 231         int err;
 232         struct resource *r;
 233         struct rdc321x_wdt_pdata *pdata;
 234
 235         pdata = mfd_get_data(pdev);
 236         if (!pdata) {
 237                 dev_err(&pdev->dev, "no platform data supplied\n");
 238                 return -ENODEV;
 239         }
 240
 241         r = platform_get_resource_byname(pdev, IORESOURCE_IO, "wdt-reg");
 242         if (!r) {
 243                 dev_err(&pdev->dev, "failed to get wdt-reg resource\n");
 244                 return -ENODEV;
 245         }
 246
 247         rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
 248         rdc321x_wdt_device.base_reg = r->start;
 249
 250         err = misc_register(&rdc321x_wdt_misc);
 251         if (err < 0) {
 252                 dev_err(&pdev->dev, "misc_register failed\n");
 253                 return err;
 254         }
 255
 256         spin_lock_init(&rdc321x_wdt_device.lock);
 257
 258         /* Reset the watchdog */
 259         pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
 260                                 rdc321x_wdt_device.base_reg, RDC_WDT_RST);
 261
 262         init_completion(&rdc321x_wdt_device.stop);
 263         rdc321x_wdt_device.queue = 0;
 264
 265         clear_bit(0, &rdc321x_wdt_device.inuse);
 266
 267         setup_timer(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
 268
 269         rdc321x_wdt_device.default_ticks = ticks;
 270
 271         dev_info(&pdev->dev, "watchdog init success\n");
 272
 273         return 0;
 274 }
 275
 276 static int __devexit rdc321x_wdt_remove(struct platform_device *pdev)
 277 {
 278         if (rdc321x_wdt_device.queue) {
 279                 rdc321x_wdt_device.queue = 0;
 280                 wait_for_completion(&rdc321x_wdt_device.stop);
 281         }
 282
 283         misc_deregister(&rdc321x_wdt_misc);
 284
 285         return 0;
 286 }
 287
 288 static struct platform_driver rdc321x_wdt_driver = {
 289         .probe = rdc321x_wdt_probe,
 290         .remove = __devexit_p(rdc321x_wdt_remove),
 291         .driver = {
 292                 .owner = THIS_MODULE,
 293                 .name = "rdc321x-wdt",
 294         },
 295 };
 296
 297 static int __init rdc321x_wdt_init(void)
 298 {
 299         return platform_driver_register(&rdc321x_wdt_driver);
 300 }
 301
 302 static void __exit rdc321x_wdt_exit(void)
 303 {
 304         platform_driver_unregister(&rdc321x_wdt_driver);
 305 }
 306
 307 module_init(rdc321x_wdt_init);
 308 module_exit(rdc321x_wdt_exit);
 309
 310 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 311 MODULE_DESCRIPTION("RDC321x watchdog driver");
 312 MODULE_LICENSE("GPL");
 313 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);