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
  41 #define RDC_WDT_MASK    0x80000000 /* Mask */
  42 #define RDC_WDT_EN      0x00800000 /* Enable bit */
  43 #define RDC_WDT_WTI     0x00200000 /* Generate CPU reset/NMI/WDT on timeout */
  44 #define RDC_WDT_RST     0x00100000 /* Reset bit */
  45 #define RDC_WDT_WIF     0x00040000 /* WDT IRQ Flag */
  46 #define RDC_WDT_IRT     0x00000100 /* IRQ Routing table */
  47 #define RDC_WDT_CNT     0x00000001 /* WDT count */
  48
  49 #define RDC_CLS_TMR     0x80003844 /* Clear timer */
  50
  51 #define RDC_WDT_INTERVAL        (HZ/10+1)
  52
  53 static int ticks = 1000;
  54
  55 /* some device data */
  56
  57 static struct {
  58         struct completion stop;
  59         int running;
  60         struct timer_list timer;
  61         int queue;
  62         int default_ticks;
  63         unsigned long inuse;
  64         spinlock_t lock;
  65         struct pci_dev *sb_pdev;
  66         int base_reg;
  67 } rdc321x_wdt_device;
  68
  69 /* generic helper functions */
  70
  71 static void rdc321x_wdt_trigger(unsigned long unused)
  72 {
  73         unsigned long flags;
  74         u32 val;
  75
  76         if (rdc321x_wdt_device.running)
  77                 ticks--;
  78
  79         /* keep watchdog alive */
  80         spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
  81         pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
  82                                         rdc321x_wdt_device.base_reg, &val);
  83         val |= RDC_WDT_EN;
  84         pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
  85                                         rdc321x_wdt_device.base_reg, val);
  86         spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
  87
  88         /* requeue?? */
  89         if (rdc321x_wdt_device.queue && ticks)
  90                 mod_timer(&rdc321x_wdt_device.timer,
  91                                 jiffies + RDC_WDT_INTERVAL);
  92         else {
  93                 /* ticks doesn't matter anyway */
  94                 complete(&rdc321x_wdt_device.stop);
  95         }
  96
  97 }
  98
  99 static void rdc321x_wdt_reset(void)
 100 {
 101         ticks = rdc321x_wdt_device.default_ticks;
 102 }
 103
 104 static void rdc321x_wdt_start(void)
 105 {
 106         unsigned long flags;
 107
 108         if (!rdc321x_wdt_device.queue) {
 109                 rdc321x_wdt_device.queue = 1;
 110
 111                 /* Clear the timer */
 112                 spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
 113                 pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
 114                                 rdc321x_wdt_device.base_reg, RDC_CLS_TMR);
 115
 116                 /* Enable watchdog and set the timeout to 81.92 us */
 117                 pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
 118                                         rdc321x_wdt_device.base_reg,
 119                                         RDC_WDT_EN | RDC_WDT_CNT);
 120                 spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
 121
 122                 mod_timer(&rdc321x_wdt_device.timer,
 123                                 jiffies + RDC_WDT_INTERVAL);
 124         }
 125
 126         /* if process dies, counter is not decremented */
 127         rdc321x_wdt_device.running++;
 128 }
 129
 130 static int rdc321x_wdt_stop(void)
 131 {
 132         if (rdc321x_wdt_device.running)
 133                 rdc321x_wdt_device.running = 0;
 134
 135         ticks = rdc321x_wdt_device.default_ticks;
 136
 137         return -EIO;
 138 }
 139
 140 /* filesystem operations */
 141 static int rdc321x_wdt_open(struct inode *inode, struct file *file)
 142 {
 143         if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
 144                 return -EBUSY;
 145
 146         return nonseekable_open(inode, file);
 147 }
 148
 149 static int rdc321x_wdt_release(struct inode *inode, struct file *file)
 150 {
 151         clear_bit(0, &rdc321x_wdt_device.inuse);
 152         return 0;
 153 }
 154
 155 static long rdc321x_wdt_ioctl(struct file *file, unsigned int cmd,
 156                                 unsigned long arg)
 157 {
 158         void __user *argp = (void __user *)arg;
 159         u32 value;
 160         static const struct watchdog_info ident = {
 161                 .options = WDIOF_CARDRESET,
 162                 .identity = "RDC321x WDT",
 163         };
 164         unsigned long flags;
 165
 166         switch (cmd) {
 167         case WDIOC_KEEPALIVE:
 168                 rdc321x_wdt_reset();
 169                 break;
 170         case WDIOC_GETSTATUS:
 171                 /* Read the value from the DATA register */
 172                 spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
 173                 pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
 174                                         rdc321x_wdt_device.base_reg, &value);
 175                 spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
 176                 if (copy_to_user(argp, &value, sizeof(u32)))
 177                         return -EFAULT;
 178                 break;
 179         case WDIOC_GETSUPPORT:
 180                 if (copy_to_user(argp, &ident, sizeof(ident)))
 181                         return -EFAULT;
 182                 break;
 183         case WDIOC_SETOPTIONS:
 184                 if (copy_from_user(&value, argp, sizeof(int)))
 185                         return -EFAULT;
 186                 switch (value) {
 187                 case WDIOS_ENABLECARD:
 188                         rdc321x_wdt_start();
 189                         break;
 190                 case WDIOS_DISABLECARD:
 191                         return rdc321x_wdt_stop();
 192                 default:
 193                         return -EINVAL;
 194                 }
 195                 break;
 196         default:
 197                 return -ENOTTY;
 198         }
 199         return 0;
 200 }
 201
 202 static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf,
 203                                 size_t count, loff_t *ppos)
 204 {
 205         if (!count)
 206                 return -EIO;
 207
 208         rdc321x_wdt_reset();
 209
 210         return count;
 211 }
 212
 213 static const struct file_operations rdc321x_wdt_fops = {
 214         .owner          = THIS_MODULE,
 215         .llseek         = no_llseek,
 216         .unlocked_ioctl = rdc321x_wdt_ioctl,
 217         .open           = rdc321x_wdt_open,
 218         .write          = rdc321x_wdt_write,
 219         .release        = rdc321x_wdt_release,
 220 };
 221
 222 static struct miscdevice rdc321x_wdt_misc = {
 223         .minor  = WATCHDOG_MINOR,
 224         .name   = "watchdog",
 225         .fops   = &rdc321x_wdt_fops,
 226 };
 227
 228 static int rdc321x_wdt_probe(struct platform_device *pdev)
 229 {
 230         int err;
 231         struct resource *r;
 232         struct rdc321x_wdt_pdata *pdata;
 233
 234         pdata = pdev->dev.platform_data;
 235         if (!pdata) {
 236                 dev_err(&pdev->dev, "no platform data supplied\n");
 237                 return -ENODEV;
 238         }
 239
 240         r = platform_get_resource_byname(pdev, IORESOURCE_IO, "wdt-reg");
 241         if (!r) {
 242                 dev_err(&pdev->dev, "failed to get wdt-reg resource\n");
 243                 return -ENODEV;
 244         }
 245
 246         rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
 247         rdc321x_wdt_device.base_reg = r->start;
 248
 249         err = misc_register(&rdc321x_wdt_misc);
 250         if (err < 0) {
 251                 dev_err(&pdev->dev, "misc_register failed\n");
 252                 return err;
 253         }
 254
 255         spin_lock_init(&rdc321x_wdt_device.lock);
 256
 257         /* Reset the watchdog */
 258         pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
 259                                 rdc321x_wdt_device.base_reg, RDC_WDT_RST);
 260
 261         init_completion(&rdc321x_wdt_device.stop);
 262         rdc321x_wdt_device.queue = 0;
 263
 264         clear_bit(0, &rdc321x_wdt_device.inuse);
 265
 266         setup_timer(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
 267
 268         rdc321x_wdt_device.default_ticks = ticks;
 269
 270         dev_info(&pdev->dev, "watchdog init success\n");
 271
 272         return 0;
 273 }
 274
 275 static int rdc321x_wdt_remove(struct platform_device *pdev)
 276 {
 277         if (rdc321x_wdt_device.queue) {
 278                 rdc321x_wdt_device.queue = 0;
 279                 wait_for_completion(&rdc321x_wdt_device.stop);
 280         }
 281
 282         misc_deregister(&rdc321x_wdt_misc);
 283
 284         return 0;
 285 }
 286
 287 static struct platform_driver rdc321x_wdt_driver = {
 288         .probe = rdc321x_wdt_probe,
 289         .remove = rdc321x_wdt_remove,
 290         .driver = {
 291                 .owner = THIS_MODULE,
 292                 .name = "rdc321x-wdt",
 293         },
 294 };
 295
 296 module_platform_driver(rdc321x_wdt_driver);
 297
 298 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 299 MODULE_DESCRIPTION("RDC321x watchdog driver");
 300 MODULE_LICENSE("GPL");
 301 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);