drivers/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/notifier.h>
  30 #include <linux/miscdevice.h>
  31 #include <linux/watchdog.h>
  32 #include <linux/io.h>
  33 #include <linux/uaccess.h>
  34 #include <asm/atomic.h>
  35 #include <asm/processor.h>
  36 #include <asm/system.h>
  37 #include <asm/rm9k-ocd.h>
  38
  39 #include <rm9k_wdt.h>
  40
  41
  42 #define CLOCK                  125000000
  43 #define MAX_TIMEOUT_SECONDS    32
  44 #define CPCCR                  0x0080
  45 #define CPGIG1SR               0x0044
  46 #define CPGIG1ER               0x0054
  47
  48
  49 /* Function prototypes */
  50 static irqreturn_t wdt_gpi_irqhdl(int, void *);
  51 static void wdt_gpi_start(void);
  52 static void wdt_gpi_stop(void);
  53 static void wdt_gpi_set_timeout(unsigned int);
  54 static int wdt_gpi_open(struct inode *, struct file *);
  55 static int wdt_gpi_release(struct inode *, struct file *);
  56 static ssize_t wdt_gpi_write(struct file *, const char __user *, size_t,
  57                                                                 loff_t *);
  58 static long wdt_gpi_ioctl(struct file *, unsigned int, unsigned long);
  59 static int wdt_gpi_notify(struct notifier_block *, unsigned long, void *);
  60 static const struct resource *wdt_gpi_get_resource(struct platform_device *,
  61                                                 const char *, unsigned int);
  62 static int __init wdt_gpi_probe(struct platform_device *);
  63 static int __exit wdt_gpi_remove(struct platform_device *);
  64
  65
  66 static const char wdt_gpi_name[] = "wdt_gpi";
  67 static atomic_t opencnt;
  68 static int expect_close;
  69 static int locked;
  70
  71
  72 /* These are set from device resources */
  73 static void __iomem *wd_regs;
  74 static unsigned int wd_irq, wd_ctr;
  75
  76
  77 /* Module arguments */
  78 static int timeout = MAX_TIMEOUT_SECONDS;
  79 module_param(timeout, int, 0444);
  80 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
  81
  82 static unsigned long resetaddr = 0xbffdc200;
  83 module_param(resetaddr, ulong, 0444);
  84 MODULE_PARM_DESC(resetaddr, "Address to write to to force a reset");
  85
  86 static unsigned long flagaddr = 0xbffdc104;
  87 module_param(flagaddr, ulong, 0444);
  88 MODULE_PARM_DESC(flagaddr, "Address to write to boot flags to");
  89
  90 static int powercycle;
  91 module_param(powercycle, bool, 0444);
  92 MODULE_PARM_DESC(powercycle, "Cycle power if watchdog expires");
  93
  94 static int nowayout = WATCHDOG_NOWAYOUT;
  95 module_param(nowayout, bool, 0444);
  96 MODULE_PARM_DESC(nowayout, "Watchdog cannot be disabled once started");
  97
  98
  99 /* Kernel interfaces */
 100 static const struct file_operations fops = {
 101         .owner          = THIS_MODULE,
 102         .open           = wdt_gpi_open,
 103         .release        = wdt_gpi_release,
 104         .write          = wdt_gpi_write,
 105         .unlocked_ioctl = wdt_gpi_ioctl,
 106 };
 107
 108 static struct miscdevice miscdev = {
 109         .minor          = WATCHDOG_MINOR,
 110         .name           = wdt_gpi_name,
 111         .fops           = &fops,
 112 };
 113
 114 static struct notifier_block wdt_gpi_shutdown = {
 115         .notifier_call  = wdt_gpi_notify,
 116 };
 117
 118
 119 /* Interrupt handler */
 120 static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt)
 121 {
 122         if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
 123                 return IRQ_NONE;
 124         __raw_writel(0x1, wd_regs + 0x0008);
 125
 126
 127         printk(KERN_CRIT "%s: watchdog expired - resetting system\n",
 128                 wdt_gpi_name);
 129
 130         *(volatile char *) flagaddr |= 0x01;
 131         *(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
 132         iob();
 133         while (1)
 134                 cpu_relax();
 135 }
 136
 137
 138 /* Watchdog functions */
 139 static void wdt_gpi_start(void)
 140 {
 141         u32 reg;
 142
 143         lock_titan_regs();
 144         reg = titan_readl(CPGIG1ER);
 145         titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
 146         iob();
 147         unlock_titan_regs();
 148 }
 149
 150 static void wdt_gpi_stop(void)
 151 {
 152         u32 reg;
 153
 154         lock_titan_regs();
 155         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 156         titan_writel(reg, CPCCR);
 157         reg = titan_readl(CPGIG1ER);
 158         titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
 159         iob();
 160         unlock_titan_regs();
 161 }
 162
 163 static void wdt_gpi_set_timeout(unsigned int to)
 164 {
 165         u32 reg;
 166         const u32 wdval = (to * CLOCK) & ~0x0000000f;
 167
 168         lock_titan_regs();
 169         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 170         titan_writel(reg, CPCCR);
 171         wmb();
 172         __raw_writel(wdval, wd_regs + 0x0000);
 173         wmb();
 174         titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
 175         wmb();
 176         titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
 177         iob();
 178         unlock_titan_regs();
 179 }
 180
 181
 182 /* /dev/watchdog operations */
 183 static int wdt_gpi_open(struct inode *inode, struct file *file)
 184 {
 185         int res;
 186
 187         if (unlikely(atomic_dec_if_positive(&opencnt) < 0))
 188                 return -EBUSY;
 189
 190         expect_close = 0;
 191         if (locked) {
 192                 module_put(THIS_MODULE);
 193                 free_irq(wd_irq, &miscdev);
 194                 locked = 0;
 195         }
 196
 197         res = request_irq(wd_irq, wdt_gpi_irqhdl, IRQF_SHARED | IRQF_DISABLED,
 198                           wdt_gpi_name, &miscdev);
 199         if (unlikely(res))
 200                 return res;
 201
 202         wdt_gpi_set_timeout(timeout);
 203         wdt_gpi_start();
 204
 205         printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
 206                 wdt_gpi_name, timeout);
 207         return nonseekable_open(inode, file);
 208 }
 209
 210 static int wdt_gpi_release(struct inode *inode, struct file *file)
 211 {
 212         if (nowayout) {
 213                 printk(KERN_INFO "%s: no way out - watchdog left running\n",
 214                         wdt_gpi_name);
 215                 __module_get(THIS_MODULE);
 216                 locked = 1;
 217         } else {
 218                 if (expect_close) {
 219                         wdt_gpi_stop();
 220                         free_irq(wd_irq, &miscdev);
 221                         printk(KERN_INFO "%s: watchdog stopped\n",
 222                                                         wdt_gpi_name);
 223                 } else {
 224                         printk(KERN_CRIT "%s: unexpected close() -"
 225                                 " watchdog left running\n",
 226                                 wdt_gpi_name);
 227                         wdt_gpi_set_timeout(timeout);
 228                         __module_get(THIS_MODULE);
 229                         locked = 1;
 230                 }
 231         }
 232
 233         atomic_inc(&opencnt);
 234         return 0;
 235 }
 236
 237 static ssize_t wdt_gpi_write(struct file *f, const char __user *d, size_t s,
 238                                                                 loff_t *o)
 239 {
 240         char val;
 241
 242         wdt_gpi_set_timeout(timeout);
 243         expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
 244         return s ? 1 : 0;
 245 }
 246
 247 static long wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 248 {
 249         long res = -ENOTTY;
 250         const long size = _IOC_SIZE(cmd);
 251         int stat;
 252         void __user *argp = (void __user *)arg;
 253         static struct watchdog_info wdinfo = {
 254                 .identity               = "RM9xxx/GPI watchdog",
 255                 .firmware_version       = 0,
 256                 .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
 257         };
 258
 259         if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
 260                 return -ENOTTY;
 261
 262         if ((_IOC_DIR(cmd) & _IOC_READ)
 263             && !access_ok(VERIFY_WRITE, arg, size))
 264                 return -EFAULT;
 265
 266         if ((_IOC_DIR(cmd) & _IOC_WRITE)
 267             && !access_ok(VERIFY_READ, arg, size))
 268                 return -EFAULT;
 269
 270         expect_close = 0;
 271
 272         switch (cmd) {
 273         case WDIOC_GETSUPPORT:
 274                 wdinfo.options = nowayout ?
 275                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
 276                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 277                         WDIOF_MAGICCLOSE;
 278                 res = __copy_to_user(argp, &wdinfo, size) ?  -EFAULT : size;
 279                 break;
 280
 281         case WDIOC_GETSTATUS:
 282                 break;
 283
 284         case WDIOC_GETBOOTSTATUS:
 285                 stat = (*(volatile char *) flagaddr & 0x01)
 286                         ? WDIOF_CARDRESET : 0;
 287                 res = __copy_to_user(argp, &stat, size) ?
 288                         -EFAULT : size;
 289                 break;
 290
 291         case WDIOC_SETOPTIONS:
 292                 break;
 293
 294         case WDIOC_KEEPALIVE:
 295                 wdt_gpi_set_timeout(timeout);
 296                 res = size;
 297                 break;
 298
 299         case WDIOC_SETTIMEOUT:
 300                 {
 301                         int val;
 302                         if (unlikely(__copy_from_user(&val, argp, size))) {
 303                                 res = -EFAULT;
 304                                 break;
 305                         }
 306
 307                         if (val > MAX_TIMEOUT_SECONDS)
 308                                 val = MAX_TIMEOUT_SECONDS;
 309                         timeout = val;
 310                         wdt_gpi_set_timeout(val);
 311                         res = size;
 312                         printk(KERN_INFO "%s: timeout set to %u seconds\n",
 313                                 wdt_gpi_name, timeout);
 314                 }
 315                 break;
 316
 317         case WDIOC_GETTIMEOUT:
 318                 res = __copy_to_user(argp, &timeout, size) ?
 319                         -EFAULT : size;
 320                 break;
 321         }
 322
 323         return res;
 324 }
 325
 326
 327 /* Shutdown notifier */
 328 static int wdt_gpi_notify(struct notifier_block *this, unsigned long code,
 329                           void *unused)
 330 {
 331         if (code == SYS_DOWN || code == SYS_HALT)
 332                 wdt_gpi_stop();
 333
 334         return NOTIFY_DONE;
 335 }
 336
 337
 338 /* Init & exit procedures */
 339 static const struct resource *wdt_gpi_get_resource(struct platform_device *pdv,
 340                                         const char *name, unsigned int type)
 341 {
 342         char buf[80];
 343         if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
 344                 return NULL;
 345         return platform_get_resource_byname(pdv, type, buf);
 346 }
 347
 348 /* No hotplugging on the platform bus - use __init */
 349 static int __init wdt_gpi_probe(struct platform_device *pdv)
 350 {
 351         int res;
 352         const struct resource
 353                 * const rr = wdt_gpi_get_resource(pdv, WDT_RESOURCE_REGS,
 354                                                   IORESOURCE_MEM),
 355                 * const ri = wdt_gpi_get_resource(pdv, WDT_RESOURCE_IRQ,
 356                                                   IORESOURCE_IRQ),
 357                 * const rc = wdt_gpi_get_resource(pdv, WDT_RESOURCE_COUNTER,
 358                                                   0);
 359
 360         if (unlikely(!rr || !ri || !rc))
 361                 return -ENXIO;
 362
 363         wd_regs = ioremap_nocache(rr->start, rr->end + 1 - rr->start);
 364         if (unlikely(!wd_regs))
 365                 return -ENOMEM;
 366         wd_irq = ri->start;
 367         wd_ctr = rc->start;
 368         res = misc_register(&miscdev);
 369         if (res)
 370                 iounmap(wd_regs);
 371         else
 372                 register_reboot_notifier(&wdt_gpi_shutdown);
 373         return res;
 374 }
 375
 376 static int __exit wdt_gpi_remove(struct platform_device *dev)
 377 {
 378         int res;
 379
 380         unregister_reboot_notifier(&wdt_gpi_shutdown);
 381         res = misc_deregister(&miscdev);
 382         iounmap(wd_regs);
 383         wd_regs = NULL;
 384         return res;
 385 }
 386
 387
 388 /* Device driver init & exit */
 389 static struct platform_driver wgt_gpi_driver = {
 390         .driver = {
 391                 .name           = wdt_gpi_name,
 392                 .owner          = THIS_MODULE,
 393         },
 394         .probe          = wdt_gpi_probe,
 395         .remove         = __devexit_p(wdt_gpi_remove),
 396 };
 397
 398 static int __init wdt_gpi_init_module(void)
 399 {
 400         atomic_set(&opencnt, 1);
 401         if (timeout > MAX_TIMEOUT_SECONDS)
 402                 timeout = MAX_TIMEOUT_SECONDS;
 403         return platform_driver_register(&wdt_gpi_driver);
 404 }
 405
 406 static void __exit wdt_gpi_cleanup_module(void)
 407 {
 408         platform_driver_unregister(&wdt_gpi_driver);
 409 }
 410
 411 module_init(wdt_gpi_init_module);
 412 module_exit(wdt_gpi_cleanup_module);
 413
 414 MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
 415 MODULE_DESCRIPTION("Basler eXcite watchdog driver for gpi devices");
 416 MODULE_VERSION("0.1");
 417 MODULE_LICENSE("GPL");
 418 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 419