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 *);
  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 /* Kernel interfaces */
  98 static struct file_operations fops = {
  99         .owner          = THIS_MODULE,
 100         .open           = wdt_gpi_open,
 101         .release        = wdt_gpi_release,
 102         .write          = wdt_gpi_write,
 103         .unlocked_ioctl = wdt_gpi_ioctl,
 104 };
 105
 106 static struct miscdevice miscdev = {
 107         .minor          = WATCHDOG_MINOR,
 108         .name           = wdt_gpi_name,
 109         .fops           = &fops,
 110 };
 111
 112 static struct notifier_block wdt_gpi_shutdown = {
 113         .notifier_call  = wdt_gpi_notify,
 114 };
 115
 116
 117 /* Interrupt handler */
 118 static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt)
 119 {
 120         if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
 121                 return IRQ_NONE;
 122         __raw_writel(0x1, wd_regs + 0x0008);
 123
 124
 125         printk(KERN_CRIT "%s: watchdog expired - resetting system\n",
 126                 wdt_gpi_name);
 127
 128         *(volatile char *) flagaddr |= 0x01;
 129         *(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
 130         iob();
 131         while (1)
 132                 cpu_relax();
 133 }
 134
 135
 136 /* Watchdog functions */
 137 static void wdt_gpi_start(void)
 138 {
 139         u32 reg;
 140
 141         lock_titan_regs();
 142         reg = titan_readl(CPGIG1ER);
 143         titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
 144         iob();
 145         unlock_titan_regs();
 146 }
 147
 148 static void wdt_gpi_stop(void)
 149 {
 150         u32 reg;
 151
 152         lock_titan_regs();
 153         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 154         titan_writel(reg, CPCCR);
 155         reg = titan_readl(CPGIG1ER);
 156         titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
 157         iob();
 158         unlock_titan_regs();
 159 }
 160
 161 static void wdt_gpi_set_timeout(unsigned int to)
 162 {
 163         u32 reg;
 164         const u32 wdval = (to * CLOCK) & ~0x0000000f;
 165
 166         lock_titan_regs();
 167         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
 168         titan_writel(reg, CPCCR);
 169         wmb();
 170         __raw_writel(wdval, wd_regs + 0x0000);
 171         wmb();
 172         titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
 173         wmb();
 174         titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
 175         iob();
 176         unlock_titan_regs();
 177 }
 178
 179
 180 /* /dev/watchdog operations */
 181 static int wdt_gpi_open(struct inode *inode, struct file *file)
 182 {
 183         int res;
 184
 185         if (unlikely(atomic_dec_if_positive(&opencnt) < 0))
 186                 return -EBUSY;
 187
 188         expect_close = 0;
 189         if (locked) {
 190                 module_put(THIS_MODULE);
 191                 free_irq(wd_irq, &miscdev);
 192                 locked = 0;
 193         }
 194
 195         res = request_irq(wd_irq, wdt_gpi_irqhdl, SA_SHIRQ | SA_INTERRUPT,
 196                           wdt_gpi_name, &miscdev);
 197         if (unlikely(res))
 198                 return res;
 199
 200         wdt_gpi_set_timeout(timeout);
 201         wdt_gpi_start();
 202
 203         printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
 204                 wdt_gpi_name, timeout);
 205         return nonseekable_open(inode, file);
 206 }
 207
 208 static int wdt_gpi_release(struct inode *inode, struct file *file)
 209 {
 210         if (nowayout) {
 211                 printk(KERN_INFO "%s: no way out - watchdog left running\n",
 212                         wdt_gpi_name);
 213                 __module_get(THIS_MODULE);
 214                 locked = 1;
 215         } else {
 216                 if (expect_close) {
 217                         wdt_gpi_stop();
 218                         free_irq(wd_irq, &miscdev);
 219                         printk(KERN_INFO "%s: watchdog stopped\n", wdt_gpi_name);
 220                 } else {
 221                         printk(KERN_CRIT "%s: unexpected close() -"
 222                                 " watchdog left running\n",
 223                                 wdt_gpi_name);
 224                         wdt_gpi_set_timeout(timeout);
 225                         __module_get(THIS_MODULE);
 226                         locked = 1;
 227                 }
 228         }
 229
 230         atomic_inc(&opencnt);
 231         return 0;
 232 }
 233
 234 static ssize_t
 235 wdt_gpi_write(struct file *f, const char __user *d, size_t s, loff_t *o)
 236 {
 237         char val;
 238
 239         wdt_gpi_set_timeout(timeout);
 240         expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
 241         return s ? 1 : 0;
 242 }
 243
 244 static long
 245 wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 246 {
 247         long res = -ENOTTY;
 248         const long size = _IOC_SIZE(cmd);
 249         int stat;
 250         void __user *argp = (void __user *)arg;
 251         static struct watchdog_info wdinfo = {
 252                 .identity               = "RM9xxx/GPI watchdog",
 253                 .firmware_version       = 0,
 254                 .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
 255         };
 256
 257         if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
 258                 return -ENOTTY;
 259
 260         if ((_IOC_DIR(cmd) & _IOC_READ)
 261             && !access_ok(VERIFY_WRITE, arg, size))
 262                 return -EFAULT;
 263
 264         if ((_IOC_DIR(cmd) & _IOC_WRITE)
 265             && !access_ok(VERIFY_READ, arg, size))
 266                 return -EFAULT;
 267
 268         expect_close = 0;
 269
 270         switch (cmd) {
 271         case WDIOC_GETSUPPORT:
 272                 wdinfo.options = nowayout ?
 273                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
 274                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE;
 275                 res = __copy_to_user(argp, &wdinfo, size) ?  -EFAULT : size;
 276                 break;
 277
 278         case WDIOC_GETSTATUS:
 279                 break;
 280
 281         case WDIOC_GETBOOTSTATUS:
 282                 stat = (*(volatile char *) flagaddr & 0x01)
 283                         ? WDIOF_CARDRESET : 0;
 284                 res = __copy_to_user(argp, &stat, size) ?
 285                         -EFAULT : size;
 286                 break;
 287
 288         case WDIOC_SETOPTIONS:
 289                 break;
 290
 291         case WDIOC_KEEPALIVE:
 292                 wdt_gpi_set_timeout(timeout);
 293                 res = size;
 294                 break;
 295
 296         case WDIOC_SETTIMEOUT:
 297                 {
 298                         int val;
 299                         if (unlikely(__copy_from_user(&val, argp, size))) {
 300                                 res = -EFAULT;
 301                                 break;
 302                         }
 303
 304                         if (val > MAX_TIMEOUT_SECONDS)
 305                                 val = MAX_TIMEOUT_SECONDS;
 306                         timeout = val;
 307                         wdt_gpi_set_timeout(val);
 308                         res = size;
 309                         printk(KERN_INFO "%s: timeout set to %u seconds\n",
 310                                 wdt_gpi_name, timeout);
 311                 }
 312                 break;
 313
 314         case WDIOC_GETTIMEOUT:
 315                 res = __copy_to_user(argp, &timeout, size) ?
 316                         -EFAULT : size;
 317                 break;
 318         }
 319
 320         return res;
 321 }
 322
 323
 324 /* Shutdown notifier */
 325 static int
 326 wdt_gpi_notify(struct notifier_block *this, unsigned long code, void *unused)
 327 {
 328         if (code == SYS_DOWN || code == SYS_HALT)
 329                 wdt_gpi_stop();
 330
 331         return NOTIFY_DONE;
 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