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