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/notifier.h>
  30 #include <linux/miscdevice.h>
  31 #include <linux/watchdog.h>
  32 #include <asm/io.h>
  33 #include <asm/atomic.h>
  34 #include <asm/processor.h>
  35 #include <asm/uaccess.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 *, struct pt_regs *);
  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, loff_t *);
  57 static long wdt_gpi_ioctl(struct file *, unsigned int, unsigned long);
  58 static int wdt_gpi_notify(struct notifier_block *, unsigned long, void *);
  59 static const struct resource *wdt_gpi_get_resource(struct platform_device *, const char *, unsigned int);
  60 static int __init wdt_gpi_probe(struct device *);
  61 static int __exit wdt_gpi_remove(struct device *);
  62
  63
  64 static const char wdt_gpi_name[] = "wdt_gpi";
  65 static atomic_t opencnt;
  66 static int expect_close;
  67 static int locked;
  68
  69
  70 /* These are set from device resources */
  71 static void __iomem * wd_regs;
  72 static unsigned int wd_irq, wd_ctr;
  73
  74
  75 /* Module arguments */
  76 static int timeout = MAX_TIMEOUT_SECONDS;
  77 module_param(timeout, int, 0444);
  78 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
  79
  80 static unsigned long resetaddr = 0xbffdc200;
  81 module_param(resetaddr, ulong, 0444);
  82 MODULE_PARM_DESC(resetaddr, "Address to write to to force a reset");
  83
  84 static unsigned long flagaddr = 0xbffdc104;
  85 module_param(flagaddr, ulong, 0444);
  86 MODULE_PARM_DESC(flagaddr, "Address to write to boot flags to");
  87
  88 static int powercycle;
  89 module_param(powercycle, bool, 0444);
  90 MODULE_PARM_DESC(powercycle, "Cycle power if watchdog expires");
  91
  92 static int nowayout = WATCHDOG_NOWAYOUT;
  93 module_param(nowayout, bool, 0444);
  94 MODULE_PARM_DESC(nowayout, "Watchdog cannot be disabled once started");
  95
  96
  97 /* Interrupt handler */
  98 static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt, struct pt_regs *regs)
  99 {
 100         if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
 101                 return IRQ_NONE;
 102         __raw_writel(0x1, wd_regs + 0x0008);
 103
 104
 105         printk(KERN_CRIT "%s: watchdog expired - resetting system\n",
 106                 wdt_gpi_name);
 107
 108         *(volatile char *) flagaddr |= 0x01;
 109         *(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
 110         iob();
 111         while (1)
 112                 cpu_relax();
 113 }
 114
 115
 116 /* Watchdog functions */
 117 static void wdt_gpi_start(void)
 118 {
 119         u32 reg;
 120
 121         lock_titan_regs();
 122         reg = titan_readl(CPGIG1ER);
 123         titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
 124         iob();
 125         unlock_titan_regs();
 126 }
 127
 128 static void wdt_gpi_stop(void)
 129 {
 130         u32 reg;
 131
 132         lock_titan_regs();
 133         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 134         titan_writel(reg, CPCCR);
 135         reg = titan_readl(CPGIG1ER);
 136         titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
 137         iob();
 138         unlock_titan_regs();
 139 }
 140
 141 static void wdt_gpi_set_timeout(unsigned int to)
 142 {
 143         u32 reg;
 144         const u32 wdval = (to * CLOCK) & ~0x0000000f;
 145
 146         lock_titan_regs();
 147         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 148         titan_writel(reg, CPCCR);
 149         wmb();
 150         __raw_writel(wdval, wd_regs + 0x0000);
 151         wmb();
 152         titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
 153         wmb();
 154         titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
 155         iob();
 156         unlock_titan_regs();
 157 }
 158
 159
 160 /* /dev/watchdog operations */
 161 static int wdt_gpi_open(struct inode *inode, struct file *file)
 162 {
 163         int res;
 164
 165         if (unlikely(atomic_dec_if_positive(&opencnt) < 0))
 166                 return -EBUSY;
 167
 168         expect_close = 0;
 169         if (locked) {
 170                 module_put(THIS_MODULE);
 171                 free_irq(wd_irq, &miscdev);
 172                 locked = 0;
 173         }
 174
 175         res = request_irq(wd_irq, wdt_gpi_irqhdl, SA_SHIRQ | SA_INTERRUPT,
 176                           wdt_gpi_name, &miscdev);
 177         if (unlikely(res))
 178                 return res;
 179
 180         wdt_gpi_set_timeout(timeout);
 181         wdt_gpi_start();
 182
 183         printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
 184                 wdt_gpi_name, timeout);
 185         return nonseekable_open(inode, file);
 186 }
 187
 188 static int wdt_gpi_release(struct inode *inode, struct file *file)
 189 {
 190         if (nowayout) {
 191                 printk(KERN_INFO "%s: no way out - watchdog left running\n",
 192                         wdt_gpi_name);
 193                 __module_get(THIS_MODULE);
 194                 locked = 1;
 195         } else {
 196                 if (expect_close) {
 197                         wdt_gpi_stop();
 198                         free_irq(wd_irq, &miscdev);
 199                         printk(KERN_INFO "%s: watchdog stopped\n", wdt_gpi_name);
 200                 } else {
 201                         printk(KERN_CRIT "%s: unexpected close() -"
 202                                 " watchdog left running\n",
 203                                 wdt_gpi_name);
 204                         wdt_gpi_set_timeout(timeout);
 205                         __module_get(THIS_MODULE);
 206                         locked = 1;
 207                 }
 208         }
 209
 210         atomic_inc(&opencnt);
 211         return 0;
 212 }
 213
 214 static ssize_t
 215 wdt_gpi_write(struct file *f, const char __user *d, size_t s, loff_t *o)
 216 {
 217         char val;
 218
 219         wdt_gpi_set_timeout(timeout);
 220         expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
 221         return s ? 1 : 0;
 222 }
 223
 224 static long
 225 wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 226 {
 227         long res = -ENOTTY;
 228         const long size = _IOC_SIZE(cmd);
 229         int stat;
 230         void __user *argp = (void __user *)arg;
 231         static struct watchdog_info wdinfo = {
 232                 .identity               = "RM9xxx/GPI watchdog",
 233                 .firmware_version       = 0,
 234                 .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
 235         };
 236
 237         if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
 238                 return -ENOTTY;
 239
 240         if ((_IOC_DIR(cmd) & _IOC_READ)
 241             && !access_ok(VERIFY_WRITE, arg, size))
 242                 return -EFAULT;
 243
 244         if ((_IOC_DIR(cmd) & _IOC_WRITE)
 245             && !access_ok(VERIFY_READ, arg, size))
 246                 return -EFAULT;
 247
 248         expect_close = 0;
 249
 250         switch (cmd) {
 251         case WDIOC_GETSUPPORT:
 252                 wdinfo.options = nowayout ?
 253                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
 254                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE;
 255                 res = __copy_to_user(argp, &wdinfo, size) ?  -EFAULT : size;
 256                 break;
 257
 258         case WDIOC_GETSTATUS:
 259                 break;
 260
 261         case WDIOC_GETBOOTSTATUS:
 262                 stat = (*(volatile char *) flagaddr & 0x01)
 263                         ? WDIOF_CARDRESET : 0;
 264                 res = __copy_to_user(argp, &stat, size) ?
 265                         -EFAULT : size;
 266                 break;
 267
 268         case WDIOC_SETOPTIONS:
 269                 break;
 270
 271         case WDIOC_KEEPALIVE:
 272                 wdt_gpi_set_timeout(timeout);
 273                 res = size;
 274                 break;
 275
 276         case WDIOC_SETTIMEOUT:
 277                 {
 278                         int val;
 279                         if (unlikely(__copy_from_user(&val, argp, size))) {
 280                                 res = -EFAULT;
 281                                 break;
 282                         }
 283
 284                         if (val > MAX_TIMEOUT_SECONDS)
 285                                 val = MAX_TIMEOUT_SECONDS;
 286                         timeout = val;
 287                         wdt_gpi_set_timeout(val);
 288                         res = size;
 289                         printk(KERN_INFO "%s: timeout set to %u seconds\n",
 290                                 wdt_gpi_name, timeout);
 291                 }
 292                 break;
 293
 294         case WDIOC_GETTIMEOUT:
 295                 res = __copy_to_user(argp, &timeout, size) ?
 296                         -EFAULT : size;
 297                 break;
 298         }
 299
 300         return res;
 301 }
 302
 303
 304 /* Shutdown notifier */
 305 static int
 306 wdt_gpi_notify(struct notifier_block *this, unsigned long code, void *unused)
 307 {
 308         if (code == SYS_DOWN || code == SYS_HALT)
 309                 wdt_gpi_stop();
 310
 311         return NOTIFY_DONE;
 312 }
 313
 314
 315 /* Kernel interfaces */
 316 static struct file_operations fops = {
 317         .owner          = THIS_MODULE,
 318         .open           = wdt_gpi_open,
 319         .release        = wdt_gpi_release,
 320         .write          = wdt_gpi_write,
 321         .unlocked_ioctl = wdt_gpi_ioctl,
 322 };
 323
 324 static struct miscdevice miscdev = {
 325         .minor          = WATCHDOG_MINOR,
 326         .name           = wdt_gpi_name,
 327         .fops           = &fops,
 328 };
 329
 330 static struct notifier_block wdt_gpi_shutdown = {
 331         .notifier_call  = wdt_gpi_notify,
 332 };
 333
 334
 335 /* Init & exit procedures */
 336 static const struct resource *
 337 wdt_gpi_get_resource(struct platform_device *pdv, const char *name,
 338                       unsigned int type)
 339 {
 340         char buf[80];
 341         if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
 342                 return NULL;
 343         return platform_get_resource_byname(pdv, type, buf);
 344 }
 345
 346 /* No hotplugging on the platform bus - use __init */
 347 static int __init wdt_gpi_probe(struct device *dev)
 348 {
 349         int res;
 350         struct platform_device * const pdv = to_platform_device(dev);
 351         const struct resource
 352                 * const rr = wdt_gpi_get_resource(pdv, WDT_RESOURCE_REGS,
 353                                                   IORESOURCE_MEM),
 354                 * const ri = wdt_gpi_get_resource(pdv, WDT_RESOURCE_IRQ,
 355                                                   IORESOURCE_IRQ),
 356                 * const rc = wdt_gpi_get_resource(pdv, WDT_RESOURCE_COUNTER,
 357                                                   0);
 358
 359         if (unlikely(!rr || !ri || !rc))
 360                 return -ENXIO;
 361
 362         wd_regs = ioremap_nocache(rr->start, rr->end + 1 - rr->start);
 363         if (unlikely(!wd_regs))
 364                 return -ENOMEM;
 365         wd_irq = ri->start;
 366         wd_ctr = rc->start;
 367         res = misc_register(&miscdev);
 368         if (res)
 369                 iounmap(wd_regs);
 370         else
 371                 register_reboot_notifier(&wdt_gpi_shutdown);
 372         return res;
 373 }
 374
 375 static int __exit wdt_gpi_remove(struct device *dev)
 376 {
 377         int res;
 378
 379         unregister_reboot_notifier(&wdt_gpi_shutdown);
 380         res = misc_deregister(&miscdev);
 381         iounmap(wd_regs);
 382         wd_regs = NULL;
 383         return res;
 384 }
 385
 386
 387 /* Device driver init & exit */
 388 static struct device_driver wdt_gpi_driver = {
 389         .name           = (char *) wdt_gpi_name,
 390         .bus            = &platform_bus_type,
 391         .owner          = THIS_MODULE,
 392         .probe          = wdt_gpi_probe,
 393         .remove         = __exit_p(wdt_gpi_remove),
 394         .shutdown       = NULL,
 395         .suspend        = NULL,
 396         .resume         = NULL,
 397 };
 398
 399 static int __init wdt_gpi_init_module(void)
 400 {
 401         atomic_set(&opencnt, 1);
 402         if (timeout > MAX_TIMEOUT_SECONDS)
 403                 timeout = MAX_TIMEOUT_SECONDS;
 404         return driver_register(&wdt_gpi_driver);
 405 }
 406
 407 static void __exit wdt_gpi_cleanup_module(void)
 408 {
 409         driver_unregister(&wdt_gpi_driver);
 410 }
 411
 412 module_init(wdt_gpi_init_module);
 413 module_exit(wdt_gpi_cleanup_module);
 414
 415 MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
 416 MODULE_DESCRIPTION("Basler eXcite watchdog driver for gpi devices");
 417 MODULE_VERSION("0.1");
 418 MODULE_LICENSE("GPL");
 419 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 420