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   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 int __init wdt_gpi_probe(struct device *);
  50 static int __exit wdt_gpi_remove(struct device *);
  51 static void wdt_gpi_set_timeout(unsigned int);
  52 static int wdt_gpi_open(struct inode *, struct file *);
  53 static int wdt_gpi_release(struct inode *, struct file *);
  54 static ssize_t wdt_gpi_write(struct file *, const char __user *, size_t, loff_t *);
  55 static long wdt_gpi_ioctl(struct file *, unsigned int, unsigned long);
  56 static const struct resource *wdt_gpi_get_resource(struct platform_device *, const char *, unsigned int);
  57 static int wdt_gpi_notify(struct notifier_block *, unsigned long, void *);
  58 static irqreturn_t wdt_gpi_irqhdl(int, void *, struct pt_regs *);
  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
  95 static struct file_operations fops = {
  96         .owner          = THIS_MODULE,
  97         .open           = wdt_gpi_open,
  98         .release        = wdt_gpi_release,
  99         .write          = wdt_gpi_write,
 100         .unlocked_ioctl = wdt_gpi_ioctl,
 101 };
 102
 103 static struct miscdevice miscdev = {
 104         .minor          = WATCHDOG_MINOR,
 105         .name           = wdt_gpi_name,
 106         .fops           = &fops,
 107 };
 108
 109 static struct device_driver wdt_gpi_driver = {
 110         .name           = (char *) wdt_gpi_name,
 111         .bus            = &platform_bus_type,
 112         .owner          = THIS_MODULE,
 113         .probe          = wdt_gpi_probe,
 114         .remove         = __exit_p(wdt_gpi_remove),
 115         .shutdown       = NULL,
 116         .suspend        = NULL,
 117         .resume         = NULL,
 118 };
 119
 120 static struct notifier_block wdt_gpi_shutdown = {
 121         .notifier_call  = wdt_gpi_notify,
 122 };
 123
 124
 125
 126 static const struct resource *
 127 wdt_gpi_get_resource(struct platform_device *pdv, const char *name,
 128                       unsigned int type)
 129 {
 130         char buf[80];
 131         if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
 132                 return NULL;
 133         return platform_get_resource_byname(pdv, type, buf);
 134 }
 135
 136
 137
 138 /* No hotplugging on the platform bus - use __init */
 139 static int __init wdt_gpi_probe(struct device *dev)
 140 {
 141         int res;
 142         struct platform_device * const pdv = to_platform_device(dev);
 143         const struct resource
 144                 * const rr = wdt_gpi_get_resource(pdv, WDT_RESOURCE_REGS,
 145                                                   IORESOURCE_MEM),
 146                 * const ri = wdt_gpi_get_resource(pdv, WDT_RESOURCE_IRQ,
 147                                                   IORESOURCE_IRQ),
 148                 * const rc = wdt_gpi_get_resource(pdv, WDT_RESOURCE_COUNTER,
 149                                                   0);
 150
 151         if (unlikely(!rr || !ri || !rc))
 152                 return -ENXIO;
 153
 154         wd_regs = ioremap_nocache(rr->start, rr->end + 1 - rr->start);
 155         if (unlikely(!wd_regs))
 156                 return -ENOMEM;
 157         wd_irq = ri->start;
 158         wd_ctr = rc->start;
 159         res = misc_register(&miscdev);
 160         if (res)
 161                 iounmap(wd_regs);
 162         else
 163                 register_reboot_notifier(&wdt_gpi_shutdown);
 164         return res;
 165 }
 166
 167
 168
 169 static int __exit wdt_gpi_remove(struct device *dev)
 170 {
 171         int res;
 172
 173         unregister_reboot_notifier(&wdt_gpi_shutdown);
 174         res = misc_deregister(&miscdev);
 175         iounmap(wd_regs);
 176         wd_regs = NULL;
 177         return res;
 178 }
 179
 180
 181 static void wdt_gpi_set_timeout(unsigned int to)
 182 {
 183         u32 reg;
 184         const u32 wdval = (to * CLOCK) & ~0x0000000f;
 185
 186         lock_titan_regs();
 187         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 188         titan_writel(reg, CPCCR);
 189         wmb();
 190         __raw_writel(wdval, wd_regs + 0x0000);
 191         wmb();
 192         titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
 193         wmb();
 194         titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
 195         iob();
 196         unlock_titan_regs();
 197 }
 198
 199
 200
 201 static int wdt_gpi_open(struct inode *i, struct file *f)
 202 {
 203         int res;
 204         u32 reg;
 205
 206         if (unlikely(0 > atomic_dec_if_positive(&opencnt)))
 207                 return -EBUSY;
 208
 209         expect_close = 0;
 210         if (locked) {
 211                 module_put(THIS_MODULE);
 212                 free_irq(wd_irq, &miscdev);
 213                 locked = 0;
 214         }
 215
 216         res = request_irq(wd_irq, wdt_gpi_irqhdl, SA_SHIRQ | SA_INTERRUPT,
 217                           wdt_gpi_name, &miscdev);
 218         if (unlikely(res))
 219                 return res;
 220
 221         wdt_gpi_set_timeout(timeout);
 222
 223         lock_titan_regs();
 224         reg = titan_readl(CPGIG1ER);
 225         titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
 226         iob();
 227         unlock_titan_regs();
 228
 229         printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
 230                 wdt_gpi_name, timeout);
 231         return 0;
 232 }
 233
 234
 235
 236 static int wdt_gpi_release(struct inode *i, struct file *f)
 237 {
 238         if (nowayout) {
 239                 printk(KERN_NOTICE "%s: no way out - watchdog left running\n",
 240                         wdt_gpi_name);
 241                 __module_get(THIS_MODULE);
 242                 locked = 1;
 243         } else {
 244                 if (expect_close) {
 245                         u32 reg;
 246
 247                         lock_titan_regs();
 248                         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 249                         titan_writel(reg, CPCCR);
 250                         reg = titan_readl(CPGIG1ER);
 251                         titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
 252                         iob();
 253                         unlock_titan_regs();
 254                         free_irq(wd_irq, &miscdev);
 255                         printk(KERN_INFO "%s: watchdog stopped\n", wdt_gpi_name);
 256                 } else {
 257                         printk(KERN_NOTICE "%s: unexpected close() -"
 258                                 " watchdog left running\n",
 259                                 wdt_gpi_name);
 260                         wdt_gpi_set_timeout(timeout);
 261                         __module_get(THIS_MODULE);
 262                         locked = 1;
 263                 }
 264         }
 265
 266         atomic_inc(&opencnt);
 267         return 0;
 268 }
 269
 270
 271
 272 static ssize_t
 273 wdt_gpi_write(struct file *f, const char __user *d, size_t s, loff_t *o)
 274 {
 275         char val;
 276
 277         wdt_gpi_set_timeout(timeout);
 278         expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
 279         return s ? 1 : 0;
 280 }
 281
 282
 283
 284 static long
 285 wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 286 {
 287         long res = -ENOTTY;
 288         const long size = _IOC_SIZE(cmd);
 289         int stat;
 290         static struct watchdog_info wdinfo = {
 291                 .identity               = "RM9xxx/GPI watchdog",
 292                 .firmware_version       = 0,
 293                 .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
 294         };
 295
 296         if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
 297                 return -ENOTTY;
 298
 299         if ((_IOC_DIR(cmd) & _IOC_READ)
 300             && !access_ok(VERIFY_WRITE, arg, size))
 301                 return -EFAULT;
 302
 303         if ((_IOC_DIR(cmd) & _IOC_WRITE)
 304             && !access_ok(VERIFY_READ, arg, size))
 305                 return -EFAULT;
 306
 307         expect_close = 0;
 308
 309         switch (cmd) {
 310         case WDIOC_GETSUPPORT:
 311                 wdinfo.options = nowayout ?
 312                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
 313                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE;
 314                 res = __copy_to_user((void __user *)arg, &wdinfo, size) ?
 315                         -EFAULT : size;
 316                 break;
 317
 318         case WDIOC_GETSTATUS:
 319                 break;
 320
 321         case WDIOC_GETBOOTSTATUS:
 322                 stat = (*(volatile char *) flagaddr & 0x01)
 323                         ? WDIOF_CARDRESET : 0;
 324                 res = __copy_to_user((void __user *)arg, &stat, size) ?
 325                         -EFAULT : size;
 326                 break;
 327
 328         case WDIOC_SETOPTIONS:
 329                 break;
 330
 331         case WDIOC_KEEPALIVE:
 332                 wdt_gpi_set_timeout(timeout);
 333                 res = size;
 334                 break;
 335
 336         case WDIOC_SETTIMEOUT:
 337                 {
 338                         int val;
 339                         if (unlikely(__copy_from_user(&val, (const void __user *) arg,
 340                                         size))) {
 341                                 res = -EFAULT;
 342                                 break;
 343                         }
 344
 345                         if (val > 32)
 346                                 val = 32;
 347                         timeout = val;
 348                         wdt_gpi_set_timeout(val);
 349                         res = size;
 350                         printk("%s: timeout set to %u seconds\n",
 351                                 wdt_gpi_name, timeout);
 352                 }
 353                 break;
 354
 355         case WDIOC_GETTIMEOUT:
 356                 res = __copy_to_user((void __user *) arg, &timeout, size) ?
 357                         -EFAULT : size;
 358                 break;
 359         }
 360
 361         return res;
 362 }
 363
 364
 365
 366
 367 static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt, struct pt_regs *regs)
 368 {
 369         if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
 370                 return IRQ_NONE;
 371         __raw_writel(0x1, wd_regs + 0x0008);
 372
 373
 374         printk(KERN_WARNING "%s: watchdog expired - resetting system\n",
 375                 wdt_gpi_name);
 376
 377         *(volatile char *) flagaddr |= 0x01;
 378         *(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
 379         iob();
 380         while (1)
 381                 cpu_relax();
 382 }
 383
 384
 385
 386 static int
 387 wdt_gpi_notify(struct notifier_block *this, unsigned long code, void *unused)
 388 {
 389         if(code == SYS_DOWN || code == SYS_HALT) {
 390                 u32 reg;
 391
 392                 lock_titan_regs();
 393                 reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 394                 titan_writel(reg, CPCCR);
 395                 reg = titan_readl(CPGIG1ER);
 396                 titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
 397                 iob();
 398                 unlock_titan_regs();
 399         }
 400         return NOTIFY_DONE;
 401 }
 402
 403
 404
 405 static int __init wdt_gpi_init_module(void)
 406 {
 407         atomic_set(&opencnt, 1);
 408         if (timeout > MAX_TIMEOUT_SECONDS)
 409                 timeout = MAX_TIMEOUT_SECONDS;
 410         return driver_register(&wdt_gpi_driver);
 411 }
 412
 413
 414
 415 static void __exit wdt_gpi_cleanup_module(void)
 416 {
 417         driver_unregister(&wdt_gpi_driver);
 418 }
 419
 420 module_init(wdt_gpi_init_module);
 421 module_exit(wdt_gpi_cleanup_module);
 422
 423
 424
 425 MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
 426 MODULE_DESCRIPTION("Basler eXcite watchdog driver for gpi devices");
 427 MODULE_VERSION("0.1");
 428 MODULE_LICENSE("GPL");
 429 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 430