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/ioport.h>
  31 #include <linux/timer.h>
  32 #include <linux/completion.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/watchdog.h>
  36 #include <linux/io.h>
  37 #include <linux/uaccess.h>
  38 #include <linux/mfd/rdc321x.h>
  39
  40 #define RDC_WDT_MASK    0x80000000 /* Mask */
  41 #define RDC_WDT_EN      0x00800000 /* Enable bit */
  42 #define RDC_WDT_WTI     0x00200000 /* Generate CPU reset/NMI/WDT on timeout */
  43 #define RDC_WDT_RST     0x00100000 /* Reset bit */
  44 #define RDC_WDT_WIF     0x00040000 /* WDT IRQ Flag */
  45 #define RDC_WDT_IRT     0x00000100 /* IRQ Routing table */
  46 #define RDC_WDT_CNT     0x00000001 /* WDT count */
  47
  48 #define RDC_CLS_TMR     0x80003844 /* Clear timer */
  49
  50 #define RDC_WDT_INTERVAL        (HZ/10+1)
  51
  52 static int ticks = 1000;
  53
  54 /* some device data */
  55
  56 static struct {
  57         struct completion stop;
  58         int running;
  59         struct timer_list timer;
  60         int queue;
  61         int default_ticks;
  62         unsigned long inuse;
  63         spinlock_t lock;
  64         struct pci_dev *sb_pdev;
  65         int base_reg;
  66 } rdc321x_wdt_device;
  67
  68 /* generic helper functions */
  69
  70 static void rdc321x_wdt_trigger(struct timer_list *unused)
  71 {
  72         unsigned long flags;
  73         u32 val;
  74
  75         if (rdc321x_wdt_device.running)
  76                 ticks--;
  77
  78         /* keep watchdog alive */
  79         spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
  80         pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
  81                                         rdc321x_wdt_device.base_reg, &val);
  82         val |= RDC_WDT_EN;
  83         pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
  84                                         rdc321x_wdt_device.base_reg, val);
  85         spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
  86
  87         /* requeue?? */
  88         if (rdc321x_wdt_device.queue && ticks)
  89                 mod_timer(&rdc321x_wdt_device.timer,
  90                                 jiffies + RDC_WDT_INTERVAL);
  91         else {
  92                 /* ticks doesn't matter anyway */
  93                 complete(&rdc321x_wdt_device.stop);
  94         }
  95
  96 }
  97
  98 static void rdc321x_wdt_reset(void)
  99 {
 100         ticks = rdc321x_wdt_device.default_ticks;
 101 }
 102
 103 static void rdc321x_wdt_start(void)
 104 {
 105         unsigned long flags;
 106
 107         if (!rdc321x_wdt_device.queue) {
 108                 rdc321x_wdt_device.queue = 1;
 109
 110                 /* Clear the timer */
 111                 spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
 112                 pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
 113                                 rdc321x_wdt_device.base_reg, RDC_CLS_TMR);
 114
 115                 /* Enable watchdog and set the timeout to 81.92 us */
 116                 pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
 117                                         rdc321x_wdt_device.base_reg,
 118                                         RDC_WDT_EN | RDC_WDT_CNT);
 119                 spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
 120
 121                 mod_timer(&rdc321x_wdt_device.timer,
 122                                 jiffies + RDC_WDT_INTERVAL);
 123         }
 124
 125         /* if process dies, counter is not decremented */
 126         rdc321x_wdt_device.running++;
 127 }
 128
 129 static int rdc321x_wdt_stop(void)
 130 {
 131         if (rdc321x_wdt_device.running)
 132                 rdc321x_wdt_device.running = 0;
 133
 134         ticks = rdc321x_wdt_device.default_ticks;
 135
 136         return -EIO;
 137 }
 138
 139 /* filesystem operations */
 140 static int rdc321x_wdt_open(struct inode *inode, struct file *file)
 141 {
 142         if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
 143                 return -EBUSY;
 144
 145         return nonseekable_open(inode, file);
 146 }
 147
 148 static int rdc321x_wdt_release(struct inode *inode, struct file *file)
 149 {
 150         clear_bit(0, &rdc321x_wdt_device.inuse);
 151         return 0;
 152 }
 153
 154 static long rdc321x_wdt_ioctl(struct file *file, unsigned int cmd,
 155                                 unsigned long arg)
 156 {
 157         void __user *argp = (void __user *)arg;
 158         u32 value;
 159         static const struct watchdog_info ident = {
 160                 .options = WDIOF_CARDRESET,
 161                 .identity = "RDC321x WDT",
 162         };
 163         unsigned long flags;
 164
 165         switch (cmd) {
 166         case WDIOC_KEEPALIVE:
 167                 rdc321x_wdt_reset();
 168                 break;
 169         case WDIOC_GETSTATUS:
 170                 /* Read the value from the DATA register */
 171                 spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
 172                 pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
 173                                         rdc321x_wdt_device.base_reg, &value);
 174                 spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
 175                 if (copy_to_user(argp, &value, sizeof(u32)))
 176                         return -EFAULT;
 177                 break;
 178         case WDIOC_GETSUPPORT:
 179                 if (copy_to_user(argp, &ident, sizeof(ident)))
 180                         return -EFAULT;
 181                 break;
 182         case WDIOC_SETOPTIONS:
 183                 if (copy_from_user(&value, argp, sizeof(int)))
 184                         return -EFAULT;
 185                 switch (value) {
 186                 case WDIOS_ENABLECARD:
 187                         rdc321x_wdt_start();
 188                         break;
 189                 case WDIOS_DISABLECARD:
 190                         return rdc321x_wdt_stop();
 191                 default:
 192                         return -EINVAL;
 193                 }
 194                 break;
 195         default:
 196                 return -ENOTTY;
 197         }
 198         return 0;
 199 }
 200
 201 static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf,
 202                                 size_t count, loff_t *ppos)
 203 {
 204         if (!count)
 205                 return -EIO;
 206
 207         rdc321x_wdt_reset();
 208
 209         return count;
 210 }
 211
 212 static const struct file_operations rdc321x_wdt_fops = {
 213         .owner          = THIS_MODULE,
 214         .llseek         = no_llseek,
 215         .unlocked_ioctl = rdc321x_wdt_ioctl,
 216         .open           = rdc321x_wdt_open,
 217         .write          = rdc321x_wdt_write,
 218         .release        = rdc321x_wdt_release,
 219 };
 220
 221 static struct miscdevice rdc321x_wdt_misc = {
 222         .minor  = WATCHDOG_MINOR,
 223         .name   = "watchdog",
 224         .fops   = &rdc321x_wdt_fops,
 225 };
 226
 227 static int rdc321x_wdt_probe(struct platform_device *pdev)
 228 {
 229         int err;
 230         struct resource *r;
 231         struct rdc321x_wdt_pdata *pdata;
 232
 233         pdata = dev_get_platdata(&pdev->dev);
 234         if (!pdata) {
 235                 dev_err(&pdev->dev, "no platform data supplied\n");
 236                 return -ENODEV;
 237         }
 238
 239         r = platform_get_resource_byname(pdev, IORESOURCE_IO, "wdt-reg");
 240         if (!r) {
 241                 dev_err(&pdev->dev, "failed to get wdt-reg resource\n");
 242                 return -ENODEV;
 243         }
 244
 245         rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
 246         rdc321x_wdt_device.base_reg = r->start;
 247
 248         err = misc_register(&rdc321x_wdt_misc);
 249         if (err < 0) {
 250                 dev_err(&pdev->dev, "misc_register failed\n");
 251                 return err;
 252         }
 253
 254         spin_lock_init(&rdc321x_wdt_device.lock);
 255
 256         /* Reset the watchdog */
 257         pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
 258                                 rdc321x_wdt_device.base_reg, RDC_WDT_RST);
 259
 260         init_completion(&rdc321x_wdt_device.stop);
 261         rdc321x_wdt_device.queue = 0;
 262
 263         clear_bit(0, &rdc321x_wdt_device.inuse);
 264
 265         timer_setup(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
 266
 267         rdc321x_wdt_device.default_ticks = ticks;
 268
 269         dev_info(&pdev->dev, "watchdog init success\n");
 270
 271         return 0;
 272 }
 273
 274 static int rdc321x_wdt_remove(struct platform_device *pdev)
 275 {
 276         if (rdc321x_wdt_device.queue) {
 277                 rdc321x_wdt_device.queue = 0;
 278                 wait_for_completion(&rdc321x_wdt_device.stop);
 279         }
 280
 281         misc_deregister(&rdc321x_wdt_misc);
 282
 283         return 0;
 284 }
 285
 286 static struct platform_driver rdc321x_wdt_driver = {
 287         .probe = rdc321x_wdt_probe,
 288         .remove = rdc321x_wdt_remove,
 289         .driver = {
 290                 .name = "rdc321x-wdt",
 291         },
 292 };
 293
 294 module_platform_driver(rdc321x_wdt_driver);
 295
 296 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 297 MODULE_DESCRIPTION("RDC321x watchdog driver");
 298 MODULE_LICENSE("GPL");