drivers/char/watchdog/rm9k_wdt.c

   1 /*
   2  *  Watchdog implementation for GPI h/w found on PMC-Sierra RM9xxx
   3  *  chips.
   4  *
   5  *  Copyright (C) 2004 by Basler Vision Technologies AG
   6  *  Author: Thomas Koeller <thomas.koeller@baslerweb.com>
   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/platform_device.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/fs.h>
  28 #include <linux/reboot.h>
  29 #include <linux/miscdevice.h>
  30 #include <linux/watchdog.h>
  31 #include <asm/io.h>
  32 #include <asm/atomic.h>
  33 #include <asm/processor.h>
  34 #include <asm/uaccess.h>
  35 #include <asm/system.h>
  36 #include <asm/rm9k-ocd.h>
  37
  38 #include <rm9k_wdt.h>
  39
  40
  41 #define CLOCK                  125000000
  42 #define MAX_TIMEOUT_SECONDS    32
  43 #define CPCCR                  0x0080
  44 #define CPGIG1SR               0x0044
  45 #define CPGIG1ER               0x0054
  46
  47
  48 /* Function prototypes */
  49 static irqreturn_t wdt_gpi_irqhdl(int, void *, struct pt_regs *);
  50 static void wdt_gpi_set_timeout(unsigned int);
  51 static int wdt_gpi_open(struct inode *, struct file *);
  52 static int wdt_gpi_release(struct inode *, struct file *);
  53 static ssize_t wdt_gpi_write(struct file *, const char __user *, size_t, loff_t *);
  54 static long wdt_gpi_ioctl(struct file *, unsigned int, unsigned long);
  55 static const struct resource *wdt_gpi_get_resource(struct platform_device *, const char *, unsigned int);
  56 static int wdt_gpi_notify(struct notifier_block *, unsigned long, void *);
  57 static int __init wdt_gpi_probe(struct device *);
  58 static int __exit wdt_gpi_remove(struct device *);
  59
  60
  61 static const char wdt_gpi_name[] = "wdt_gpi";
  62 static atomic_t opencnt;
  63 static int expect_close;
  64 static int locked = 0;
  65
  66
  67 /* These are set from device resources */
  68 static void __iomem * wd_regs;
  69 static unsigned int wd_irq, wd_ctr;
  70
  71
  72 /* Module arguments */
  73 static int timeout = MAX_TIMEOUT_SECONDS;
  74 module_param(timeout, int, 0444);
  75 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
  76
  77 static unsigned long resetaddr = 0xbffdc200;
  78 module_param(resetaddr, ulong, 0444);
  79 MODULE_PARM_DESC(resetaddr, "Address to write to to force a reset");
  80
  81 static unsigned long flagaddr = 0xbffdc104;
  82 module_param(flagaddr, ulong, 0444);
  83 MODULE_PARM_DESC(flagaddr, "Address to write to boot flags to");
  84
  85 static int powercycle = 0;
  86 module_param(powercycle, bool, 0444);
  87 MODULE_PARM_DESC(powercycle, "Cycle power if watchdog expires");
  88
  89 static int nowayout = WATCHDOG_NOWAYOUT;
  90 module_param(nowayout, bool, 0444);
  91 MODULE_PARM_DESC(nowayout, "Watchdog cannot be disabled once started");
  92
  93
  94 /* Interrupt handler */
  95 static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt, struct pt_regs *regs)
  96 {
  97         if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
  98                 return IRQ_NONE;
  99         __raw_writel(0x1, wd_regs + 0x0008);
 100
 101
 102         printk(KERN_WARNING "%s: watchdog expired - resetting system\n",
 103                 wdt_gpi_name);
 104
 105         *(volatile char *) flagaddr |= 0x01;
 106         *(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
 107         iob();
 108         while (1)
 109                 cpu_relax();
 110 }
 111
 112
 113 /* Watchdog functions */
 114 static void wdt_gpi_start(void)
 115 {
 116         u32 reg;
 117
 118         lock_titan_regs();
 119         reg = titan_readl(CPGIG1ER);
 120         titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
 121         iob();
 122         unlock_titan_regs();
 123 }
 124
 125 static void wdt_gpi_stop(void)
 126 {
 127         u32 reg;
 128
 129         lock_titan_regs();
 130         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 131         titan_writel(reg, CPCCR);
 132         reg = titan_readl(CPGIG1ER);
 133         titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
 134         iob();
 135         unlock_titan_regs();
 136 }
 137
 138 static void wdt_gpi_set_timeout(unsigned int to)
 139 {
 140         u32 reg;
 141         const u32 wdval = (to * CLOCK) & ~0x0000000f;
 142
 143         lock_titan_regs();
 144         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 145         titan_writel(reg, CPCCR);
 146         wmb();
 147         __raw_writel(wdval, wd_regs + 0x0000);
 148         wmb();
 149         titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
 150         wmb();
 151         titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
 152         iob();
 153         unlock_titan_regs();
 154 }
 155
 156
 157 /* /dev/watchdog operations */
 158 static int wdt_gpi_open(struct inode *i, struct file *f)
 159 {
 160         int res;
 161
 162         if (unlikely(0 > atomic_dec_if_positive(&opencnt)))
 163                 return -EBUSY;
 164
 165         expect_close = 0;
 166         if (locked) {
 167                 module_put(THIS_MODULE);
 168                 free_irq(wd_irq, &miscdev);
 169                 locked = 0;
 170         }
 171
 172         res = request_irq(wd_irq, wdt_gpi_irqhdl, SA_SHIRQ | SA_INTERRUPT,
 173                           wdt_gpi_name, &miscdev);
 174         if (unlikely(res))
 175                 return res;
 176
 177         wdt_gpi_set_timeout(timeout);
 178         wdt_gpi_start();
 179
 180         printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
 181                 wdt_gpi_name, timeout);
 182         return 0;
 183 }
 184
 185 static int wdt_gpi_release(struct inode *i, struct file *f)
 186 {
 187         if (nowayout) {
 188                 printk(KERN_NOTICE "%s: no way out - watchdog left running\n",
 189                         wdt_gpi_name);
 190                 __module_get(THIS_MODULE);
 191                 locked = 1;
 192         } else {
 193                 if (expect_close) {
 194                         wdt_gpi_stop();
 195                         free_irq(wd_irq, &miscdev);
 196                         printk(KERN_INFO "%s: watchdog stopped\n", wdt_gpi_name);
 197                 } else {
 198                         printk(KERN_NOTICE "%s: unexpected close() -"
 199                                 " watchdog left running\n",
 200                                 wdt_gpi_name);
 201                         wdt_gpi_set_timeout(timeout);
 202                         __module_get(THIS_MODULE);
 203                         locked = 1;
 204                 }
 205         }
 206
 207         atomic_inc(&opencnt);
 208         return 0;
 209 }
 210
 211 static ssize_t
 212 wdt_gpi_write(struct file *f, const char __user *d, size_t s, loff_t *o)
 213 {
 214         char val;
 215
 216         wdt_gpi_set_timeout(timeout);
 217         expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
 218         return s ? 1 : 0;
 219 }
 220
 221 static long
 222 wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 223 {
 224         long res = -ENOTTY;
 225         const long size = _IOC_SIZE(cmd);
 226         int stat;
 227         static struct watchdog_info wdinfo = {
 228                 .identity               = "RM9xxx/GPI watchdog",
 229                 .firmware_version       = 0,
 230                 .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
 231         };
 232
 233         if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
 234                 return -ENOTTY;
 235
 236         if ((_IOC_DIR(cmd) & _IOC_READ)
 237             && !access_ok(VERIFY_WRITE, arg, size))
 238                 return -EFAULT;
 239
 240         if ((_IOC_DIR(cmd) & _IOC_WRITE)
 241             && !access_ok(VERIFY_READ, arg, size))
 242                 return -EFAULT;
 243
 244         expect_close = 0;
 245
 246         switch (cmd) {
 247         case WDIOC_GETSUPPORT:
 248                 wdinfo.options = nowayout ?
 249                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
 250                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE;
 251                 res = __copy_to_user((void __user *)arg, &wdinfo, size) ?
 252                         -EFAULT : size;
 253                 break;
 254
 255         case WDIOC_GETSTATUS:
 256                 break;
 257
 258         case WDIOC_GETBOOTSTATUS:
 259                 stat = (*(volatile char *) flagaddr & 0x01)
 260                         ? WDIOF_CARDRESET : 0;
 261                 res = __copy_to_user((void __user *)arg, &stat, size) ?
 262                         -EFAULT : size;
 263                 break;
 264
 265         case WDIOC_SETOPTIONS:
 266                 break;
 267
 268         case WDIOC_KEEPALIVE:
 269                 wdt_gpi_set_timeout(timeout);
 270                 res = size;
 271                 break;
 272
 273         case WDIOC_SETTIMEOUT:
 274                 {
 275                         int val;
 276                         if (unlikely(__copy_from_user(&val, (const void __user *) arg,
 277                                         size))) {
 278                                 res = -EFAULT;
 279                                 break;
 280                         }
 281
 282                         if (val > 32)
 283                                 val = 32;
 284                         timeout = val;
 285                         wdt_gpi_set_timeout(val);
 286                         res = size;
 287                         printk("%s: timeout set to %u seconds\n",
 288                                 wdt_gpi_name, timeout);
 289                 }
 290                 break;
 291
 292         case WDIOC_GETTIMEOUT:
 293                 res = __copy_to_user((void __user *) arg, &timeout, size) ?
 294                         -EFAULT : size;
 295                 break;
 296         }
 297
 298         return res;
 299 }
 300
 301
 302 /* Shutdown notifier*/
 303 static int
 304 wdt_gpi_notify(struct notifier_block *this, unsigned long code, void *unused)
 305 {
 306         if (code == SYS_DOWN || code == SYS_HALT)
 307                 wdt_gpi_stop();
 308
 309         return NOTIFY_DONE;
 310 }
 311
 312
 313 /* Kernel interfaces */
 314 static struct file_operations fops = {
 315         .owner          = THIS_MODULE,
 316         .open           = wdt_gpi_open,
 317         .release        = wdt_gpi_release,
 318         .write          = wdt_gpi_write,
 319         .unlocked_ioctl = wdt_gpi_ioctl,
 320 };
 321
 322 static struct miscdevice miscdev = {
 323         .minor          = WATCHDOG_MINOR,
 324         .name           = wdt_gpi_name,
 325         .fops           = &fops,
 326 };
 327
 328 static struct notifier_block wdt_gpi_shutdown = {
 329         .notifier_call  = wdt_gpi_notify,
 330 };
 331
 332
 333 /* Init & exit procedures */
 334 static const struct resource *
 335 wdt_gpi_get_resource(struct platform_device *pdv, const char *name,
 336                       unsigned int type)
 337 {
 338         char buf[80];
 339         if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
 340                 return NULL;
 341         return platform_get_resource_byname(pdv, type, buf);
 342 }
 343
 344 /* No hotplugging on the platform bus - use __init */
 345 static int __init wdt_gpi_probe(struct device *dev)
 346 {
 347         int res;
 348         struct platform_device * const pdv = to_platform_device(dev);
 349         const struct resource
 350                 * const rr = wdt_gpi_get_resource(pdv, WDT_RESOURCE_REGS,
 351                                                   IORESOURCE_MEM),
 352                 * const ri = wdt_gpi_get_resource(pdv, WDT_RESOURCE_IRQ,
 353                                                   IORESOURCE_IRQ),
 354                 * const rc = wdt_gpi_get_resource(pdv, WDT_RESOURCE_COUNTER,
 355                                                   0);
 356
 357         if (unlikely(!rr || !ri || !rc))
 358                 return -ENXIO;
 359
 360         wd_regs = ioremap_nocache(rr->start, rr->end + 1 - rr->start);
 361         if (unlikely(!wd_regs))
 362                 return -ENOMEM;
 363         wd_irq = ri->start;
 364         wd_ctr = rc->start;
 365         res = misc_register(&miscdev);
 366         if (res)
 367                 iounmap(wd_regs);
 368         else
 369                 register_reboot_notifier(&wdt_gpi_shutdown);
 370         return res;
 371 }
 372
 373 static int __exit wdt_gpi_remove(struct device *dev)
 374 {
 375         int res;
 376
 377         unregister_reboot_notifier(&wdt_gpi_shutdown);
 378         res = misc_deregister(&miscdev);
 379         iounmap(wd_regs);
 380         wd_regs = NULL;
 381         return res;
 382 }
 383
 384
 385 /* Device driver init & exit */
 386 static struct device_driver wdt_gpi_driver = {
 387         .name           = (char *) wdt_gpi_name,
 388         .bus            = &platform_bus_type,
 389         .owner          = THIS_MODULE,
 390         .probe          = wdt_gpi_probe,
 391         .remove         = __exit_p(wdt_gpi_remove),
 392         .shutdown       = NULL,
 393         .suspend        = NULL,
 394         .resume         = NULL,
 395 };
 396
 397 static int __init wdt_gpi_init_module(void)
 398 {
 399         atomic_set(&opencnt, 1);
 400         if (timeout > MAX_TIMEOUT_SECONDS)
 401                 timeout = MAX_TIMEOUT_SECONDS;
 402         return driver_register(&wdt_gpi_driver);
 403 }
 404
 405 static void __exit wdt_gpi_cleanup_module(void)
 406 {
 407         driver_unregister(&wdt_gpi_driver);
 408 }
 409
 410 module_init(wdt_gpi_init_module);
 411 module_exit(wdt_gpi_cleanup_module);
 412
 413 MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
 414 MODULE_DESCRIPTION("Basler eXcite watchdog driver for gpi devices");
 415 MODULE_VERSION("0.1");
 416 MODULE_LICENSE("GPL");
 417 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 418