1/* cpwd.c - driver implementation for hardware watchdog 2 * timers found on Sun Microsystems CP1400 and CP1500 boards. 3 * 4 * This device supports both the generic Linux watchdog 5 * interface and Solaris-compatible ioctls as best it is 6 * able. 7 * 8 * NOTE: CP1400 systems appear to have a defective intr_mask 9 * register on the PLD, preventing the disabling of 10 * timer interrupts. We use a timer to periodically 11 * reset 'stopped' watchdogs on affected platforms. 12 * 13 * Copyright (c) 2000 Eric Brower (ebrower@usa.net) 14 * Copyright (C) 2008 David S. Miller <davem@davemloft.net> 15 */ 16 17#include <linux/kernel.h> 18#include <linux/module.h> 19#include <linux/fs.h> 20#include <linux/errno.h> 21#include <linux/major.h> 22#include <linux/init.h> 23#include <linux/miscdevice.h> 24#include <linux/interrupt.h> 25#include <linux/ioport.h> 26#include <linux/timer.h> 27#include <linux/slab.h> 28#include <linux/smp_lock.h> 29#include <linux/io.h> 30#include <linux/of.h> 31#include <linux/of_device.h> 32#include <linux/uaccess.h> 33 34#include <asm/irq.h> 35#include <asm/watchdog.h> 36 37#define DRIVER_NAME "cpwd" 38#define PFX DRIVER_NAME ": " 39 40#define WD_OBPNAME "watchdog" 41#define WD_BADMODEL "SUNW,501-5336" 42#define WD_BTIMEOUT (jiffies + (HZ * 1000)) 43#define WD_BLIMIT 0xFFFF 44 45#define WD0_MINOR 212 46#define WD1_MINOR 213 47#define WD2_MINOR 214 48 49/* Internal driver definitions. */ 50#define WD0_ID 0 51#define WD1_ID 1 52#define WD2_ID 2 53#define WD_NUMDEVS 3 54 55#define WD_INTR_OFF 0 56#define WD_INTR_ON 1 57 58#define WD_STAT_INIT 0x01 /* Watchdog timer is initialized */ 59#define WD_STAT_BSTOP 0x02 /* Watchdog timer is brokenstopped */ 60#define WD_STAT_SVCD 0x04 /* Watchdog interrupt occurred */ 61 62/* Register value definitions 63 */ 64#define WD0_INTR_MASK 0x01 /* Watchdog device interrupt masks */ 65#define WD1_INTR_MASK 0x02 66#define WD2_INTR_MASK 0x04 67 68#define WD_S_RUNNING 0x01 /* Watchdog device status running */ 69#define WD_S_EXPIRED 0x02 /* Watchdog device status expired */ 70 71struct cpwd { 72 void __iomem *regs; 73 spinlock_t lock; 74 75 unsigned int irq; 76 77 unsigned long timeout; 78 bool enabled; 79 bool reboot; 80 bool broken; 81 bool initialized; 82 83 struct { 84 struct miscdevice misc; 85 void __iomem *regs; 86 u8 intr_mask; 87 u8 runstatus; 88 u16 timeout; 89 } devs[WD_NUMDEVS]; 90}; 91 92static struct cpwd *cpwd_device; 93 94/* Sun uses Altera PLD EPF8820ATC144-4 95 * providing three hardware watchdogs: 96 * 97 * 1) RIC - sends an interrupt when triggered 98 * 2) XIR - asserts XIR_B_RESET when triggered, resets CPU 99 * 3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board 100 * 101 *** Timer register block definition (struct wd_timer_regblk) 102 * 103 * dcntr and limit registers (halfword access): 104 * ------------------- 105 * | 15 | ...| 1 | 0 | 106 * ------------------- 107 * |- counter val -| 108 * ------------------- 109 * dcntr - Current 16-bit downcounter value. 110 * When downcounter reaches '0' watchdog expires. 111 * Reading this register resets downcounter with 112 * 'limit' value. 113 * limit - 16-bit countdown value in 1/10th second increments. 114 * Writing this register begins countdown with input value. 115 * Reading from this register does not affect counter. 116 * NOTES: After watchdog reset, dcntr and limit contain '1' 117 * 118 * status register (byte access): 119 * --------------------------- 120 * | 7 | ... | 2 | 1 | 0 | 121 * --------------+------------ 122 * |- UNUSED -| EXP | RUN | 123 * --------------------------- 124 * status- Bit 0 - Watchdog is running 125 * Bit 1 - Watchdog has expired 126 * 127 *** PLD register block definition (struct wd_pld_regblk) 128 * 129 * intr_mask register (byte access): 130 * --------------------------------- 131 * | 7 | ... | 3 | 2 | 1 | 0 | 132 * +-------------+------------------ 133 * |- UNUSED -| WD3 | WD2 | WD1 | 134 * --------------------------------- 135 * WD3 - 1 == Interrupt disabled for watchdog 3 136 * WD2 - 1 == Interrupt disabled for watchdog 2 137 * WD1 - 1 == Interrupt disabled for watchdog 1 138 * 139 * pld_status register (byte access): 140 * UNKNOWN, MAGICAL MYSTERY REGISTER 141 * 142 */ 143#define WD_TIMER_REGSZ 16 144#define WD0_OFF 0 145#define WD1_OFF (WD_TIMER_REGSZ * 1) 146#define WD2_OFF (WD_TIMER_REGSZ * 2) 147#define PLD_OFF (WD_TIMER_REGSZ * 3) 148 149#define WD_DCNTR 0x00 150#define WD_LIMIT 0x04 151#define WD_STATUS 0x08 152 153#define PLD_IMASK (PLD_OFF + 0x00) 154#define PLD_STATUS (PLD_OFF + 0x04) 155 156static struct timer_list cpwd_timer; 157 158static int wd0_timeout; 159static int wd1_timeout; 160static int wd2_timeout; 161 162module_param(wd0_timeout, int, 0); 163MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs"); 164module_param(wd1_timeout, int, 0); 165MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs"); 166module_param(wd2_timeout, int, 0); 167MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs"); 168 169MODULE_AUTHOR("Eric Brower <ebrower@usa.net>"); 170MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500"); 171MODULE_LICENSE("GPL"); 172MODULE_SUPPORTED_DEVICE("watchdog"); 173 174static void cpwd_writew(u16 val, void __iomem *addr) 175{ 176 writew(cpu_to_le16(val), addr); 177} 178static u16 cpwd_readw(void __iomem *addr) 179{ 180 u16 val = readw(addr); 181 182 return le16_to_cpu(val); 183} 184 185static void cpwd_writeb(u8 val, void __iomem *addr) 186{ 187 writeb(val, addr); 188} 189 190static u8 cpwd_readb(void __iomem *addr) 191{ 192 return readb(addr); 193} 194 195/* Enable or disable watchdog interrupts 196 * Because of the CP1400 defect this should only be 197 * called during initialzation or by wd_[start|stop]timer() 198 * 199 * index - sub-device index, or -1 for 'all' 200 * enable - non-zero to enable interrupts, zero to disable 201 */ 202static void cpwd_toggleintr(struct cpwd *p, int index, int enable) 203{ 204 unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK); 205 unsigned char setregs = 206 (index == -1) ? 207 (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) : 208 (p->devs[index].intr_mask); 209 210 if (enable == WD_INTR_ON) 211 curregs &= ~setregs; 212 else 213 curregs |= setregs; 214 215 cpwd_writeb(curregs, p->regs + PLD_IMASK); 216} 217 218/* Restarts timer with maximum limit value and 219 * does not unset 'brokenstop' value. 220 */ 221static void cpwd_resetbrokentimer(struct cpwd *p, int index) 222{ 223 cpwd_toggleintr(p, index, WD_INTR_ON); 224 cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT); 225} 226 227/* Timer method called to reset stopped watchdogs-- 228 * because of the PLD bug on CP1400, we cannot mask 229 * interrupts within the PLD so me must continually 230 * reset the timers ad infinitum. 231 */ 232static void cpwd_brokentimer(unsigned long data) 233{ 234 struct cpwd *p = (struct cpwd *) data; 235 int id, tripped = 0; 236 237 /* kill a running timer instance, in case we 238 * were called directly instead of by kernel timer 239 */ 240 if (timer_pending(&cpwd_timer)) 241 del_timer(&cpwd_timer); 242 243 for (id = 0; id < WD_NUMDEVS; id++) { 244 if (p->devs[id].runstatus & WD_STAT_BSTOP) { 245 ++tripped; 246 cpwd_resetbrokentimer(p, id); 247 } 248 } 249 250 if (tripped) { 251 /* there is at least one timer brokenstopped-- reschedule */ 252 cpwd_timer.expires = WD_BTIMEOUT; 253 add_timer(&cpwd_timer); 254 } 255} 256 257/* Reset countdown timer with 'limit' value and continue countdown. 258 * This will not start a stopped timer. 259 */ 260static void cpwd_pingtimer(struct cpwd *p, int index) 261{ 262 if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) 263 cpwd_readw(p->devs[index].regs + WD_DCNTR); 264} 265 266/* Stop a running watchdog timer-- the timer actually keeps 267 * running, but the interrupt is masked so that no action is 268 * taken upon expiration. 269 */ 270static void cpwd_stoptimer(struct cpwd *p, int index) 271{ 272 if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) { 273 cpwd_toggleintr(p, index, WD_INTR_OFF); 274 275 if (p->broken) { 276 p->devs[index].runstatus |= WD_STAT_BSTOP; 277 cpwd_brokentimer((unsigned long) p); 278 } 279 } 280} 281 282/* Start a watchdog timer with the specified limit value 283 * If the watchdog is running, it will be restarted with 284 * the provided limit value. 285 * 286 * This function will enable interrupts on the specified 287 * watchdog. 288 */ 289static void cpwd_starttimer(struct cpwd *p, int index) 290{ 291 if (p->broken) 292 p->devs[index].runstatus &= ~WD_STAT_BSTOP; 293 294 p->devs[index].runstatus &= ~WD_STAT_SVCD; 295 296 cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT); 297 cpwd_toggleintr(p, index, WD_INTR_ON); 298} 299 300static int cpwd_getstatus(struct cpwd *p, int index) 301{ 302 unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS); 303 unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK); 304 unsigned char ret = WD_STOPPED; 305 306 /* determine STOPPED */ 307 if (!stat) 308 return ret; 309 310 /* determine EXPIRED vs FREERUN vs RUNNING */ 311 else if (WD_S_EXPIRED & stat) { 312 ret = WD_EXPIRED; 313 } else if (WD_S_RUNNING & stat) { 314 if (intr & p->devs[index].intr_mask) { 315 ret = WD_FREERUN; 316 } else { 317 /* Fudge WD_EXPIRED status for defective CP1400-- 318 * IF timer is running 319 * AND brokenstop is set 320 * AND an interrupt has been serviced 321 * we are WD_EXPIRED. 322 * 323 * IF timer is running 324 * AND brokenstop is set 325 * AND no interrupt has been serviced 326 * we are WD_FREERUN. 327 */ 328 if (p->broken && 329 (p->devs[index].runstatus & WD_STAT_BSTOP)) { 330 if (p->devs[index].runstatus & WD_STAT_SVCD) { 331 ret = WD_EXPIRED; 332 } else { 333 /* we could as well pretend 334 * we are expired */ 335 ret = WD_FREERUN; 336 } 337 } else { 338 ret = WD_RUNNING; 339 } 340 } 341 } 342 343 /* determine SERVICED */ 344 if (p->devs[index].runstatus & WD_STAT_SVCD) 345 ret |= WD_SERVICED; 346 347 return ret; 348} 349 350static irqreturn_t cpwd_interrupt(int irq, void *dev_id) 351{ 352 struct cpwd *p = dev_id; 353 354 /* Only WD0 will interrupt-- others are NMI and we won't 355 * see them here.... 356 */ 357 spin_lock_irq(&p->lock); 358 359 cpwd_stoptimer(p, WD0_ID); 360 p->devs[WD0_ID].runstatus |= WD_STAT_SVCD; 361 362 spin_unlock_irq(&p->lock); 363 364 return IRQ_HANDLED; 365} 366 367static int cpwd_open(struct inode *inode, struct file *f) 368{ 369 struct cpwd *p = cpwd_device; 370 371 lock_kernel(); 372 switch (iminor(inode)) { 373 case WD0_MINOR: 374 case WD1_MINOR: 375 case WD2_MINOR: 376 break; 377 378 default: 379 unlock_kernel(); 380 return -ENODEV; 381 } 382 383 /* Register IRQ on first open of device */ 384 if (!p->initialized) { 385 if (request_irq(p->irq, &cpwd_interrupt, 386 IRQF_SHARED, DRIVER_NAME, p)) { 387 printk(KERN_ERR PFX "Cannot register IRQ %d\n", 388 p->irq); 389 unlock_kernel(); 390 return -EBUSY; 391 } 392 p->initialized = true; 393 } 394 395 unlock_kernel(); 396 397 return nonseekable_open(inode, f); 398} 399 400static int cpwd_release(struct inode *inode, struct file *file) 401{ 402 return 0; 403} 404 405static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 406{ 407 static const struct watchdog_info info = { 408 .options = WDIOF_SETTIMEOUT, 409 .firmware_version = 1, 410 .identity = DRIVER_NAME, 411 }; 412 void __user *argp = (void __user *)arg; 413 struct inode *inode = file->f_path.dentry->d_inode; 414 int index = iminor(inode) - WD0_MINOR; 415 struct cpwd *p = cpwd_device; 416 int setopt = 0; 417 418 switch (cmd) { 419 /* Generic Linux IOCTLs */ 420 case WDIOC_GETSUPPORT: 421 if (copy_to_user(argp, &info, sizeof(struct watchdog_info))) 422 return -EFAULT; 423 break; 424 425 case WDIOC_GETSTATUS: 426 case WDIOC_GETBOOTSTATUS: 427 if (put_user(0, (int __user *)argp)) 428 return -EFAULT; 429 break; 430 431 case WDIOC_KEEPALIVE: 432 cpwd_pingtimer(p, index); 433 break; 434 435 case WDIOC_SETOPTIONS: 436 if (copy_from_user(&setopt, argp, sizeof(unsigned int))) 437 return -EFAULT; 438 439 if (setopt & WDIOS_DISABLECARD) { 440 if (p->enabled) 441 return -EINVAL; 442 cpwd_stoptimer(p, index); 443 } else if (setopt & WDIOS_ENABLECARD) { 444 cpwd_starttimer(p, index); 445 } else { 446 return -EINVAL; 447 } 448 break; 449 450 /* Solaris-compatible IOCTLs */ 451 case WIOCGSTAT: 452 setopt = cpwd_getstatus(p, index); 453 if (copy_to_user(argp, &setopt, sizeof(unsigned int))) 454 return -EFAULT; 455 break; 456 457 case WIOCSTART: 458 cpwd_starttimer(p, index); 459 break; 460 461 case WIOCSTOP: 462 if (p->enabled) 463 return -EINVAL; 464 465 cpwd_stoptimer(p, index); 466 break; 467 468 default: 469 return -EINVAL; 470 } 471 472 return 0; 473} 474 475static long cpwd_compat_ioctl(struct file *file, unsigned int cmd, 476 unsigned long arg) 477{ 478 int rval = -ENOIOCTLCMD; 479 480 switch (cmd) { 481 /* solaris ioctls are specific to this driver */ 482 case WIOCSTART: 483 case WIOCSTOP: 484 case WIOCGSTAT: 485 lock_kernel(); 486 rval = cpwd_ioctl(file, cmd, arg); 487 unlock_kernel(); 488 break; 489 490 /* everything else is handled by the generic compat layer */ 491 default: 492 break; 493 } 494 495 return rval; 496} 497 498static ssize_t cpwd_write(struct file *file, const char __user *buf, 499 size_t count, loff_t *ppos) 500{ 501 struct inode *inode = file->f_path.dentry->d_inode; 502 struct cpwd *p = cpwd_device; 503 int index = iminor(inode); 504 505 if (count) { 506 cpwd_pingtimer(p, index); 507 return 1; 508 } 509 510 return 0; 511} 512 513static ssize_t cpwd_read(struct file *file, char __user *buffer, 514 size_t count, loff_t *ppos) 515{ 516 return -EINVAL; 517} 518 519static const struct file_operations cpwd_fops = { 520 .owner = THIS_MODULE, 521 .unlocked_ioctl = cpwd_ioctl, 522 .compat_ioctl = cpwd_compat_ioctl, 523 .open = cpwd_open, 524 .write = cpwd_write, 525 .read = cpwd_read, 526 .release = cpwd_release, 527}; 528 529static int __devinit cpwd_probe(struct platform_device *op, 530 const struct of_device_id *match) 531{ 532 struct device_node *options; 533 const char *str_prop; 534 const void *prop_val; 535 int i, err = -EINVAL; 536 struct cpwd *p; 537 538 if (cpwd_device) 539 return -EINVAL; 540 541 p = kzalloc(sizeof(*p), GFP_KERNEL); 542 err = -ENOMEM; 543 if (!p) { 544 printk(KERN_ERR PFX "Unable to allocate struct cpwd.\n"); 545 goto out; 546 } 547 548 p->irq = op->archdata.irqs[0]; 549 550 spin_lock_init(&p->lock); 551 552 p->regs = of_ioremap(&op->resource[0], 0, 553 4 * WD_TIMER_REGSZ, DRIVER_NAME); 554 if (!p->regs) { 555 printk(KERN_ERR PFX "Unable to map registers.\n"); 556 goto out_free; 557 } 558 559 options = of_find_node_by_path("/options"); 560 err = -ENODEV; 561 if (!options) { 562 printk(KERN_ERR PFX "Unable to find /options node.\n"); 563 goto out_iounmap; 564 } 565 566 prop_val = of_get_property(options, "watchdog-enable?", NULL); 567 p->enabled = (prop_val ? true : false); 568 569 prop_val = of_get_property(options, "watchdog-reboot?", NULL); 570 p->reboot = (prop_val ? true : false); 571 572 str_prop = of_get_property(options, "watchdog-timeout", NULL); 573 if (str_prop) 574 p->timeout = simple_strtoul(str_prop, NULL, 10); 575 576 /* CP1400s seem to have broken PLD implementations-- the 577 * interrupt_mask register cannot be written, so no timer 578 * interrupts can be masked within the PLD. 579 */ 580 str_prop = of_get_property(op->dev.of_node, "model", NULL); 581 p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL)); 582 583 if (!p->enabled) 584 cpwd_toggleintr(p, -1, WD_INTR_OFF); 585 586 for (i = 0; i < WD_NUMDEVS; i++) { 587 static const char *cpwd_names[] = { "RIC", "XIR", "POR" }; 588 static int *parms[] = { &wd0_timeout, 589 &wd1_timeout, 590 &wd2_timeout }; 591 struct miscdevice *mp = &p->devs[i].misc; 592 593 mp->minor = WD0_MINOR + i; 594 mp->name = cpwd_names[i]; 595 mp->fops = &cpwd_fops; 596 597 p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ); 598 p->devs[i].intr_mask = (WD0_INTR_MASK << i); 599 p->devs[i].runstatus &= ~WD_STAT_BSTOP; 600 p->devs[i].runstatus |= WD_STAT_INIT; 601 p->devs[i].timeout = p->timeout; 602 if (*parms[i]) 603 p->devs[i].timeout = *parms[i]; 604 605 err = misc_register(&p->devs[i].misc); 606 if (err) { 607 printk(KERN_ERR "Could not register misc device for " 608 "dev %d\n", i); 609 goto out_unregister; 610 } 611 } 612 613 if (p->broken) { 614 init_timer(&cpwd_timer); 615 cpwd_timer.function = cpwd_brokentimer; 616 cpwd_timer.data = (unsigned long) p; 617 cpwd_timer.expires = WD_BTIMEOUT; 618 619 printk(KERN_INFO PFX "PLD defect workaround enabled for " 620 "model " WD_BADMODEL ".\n"); 621 } 622 623 dev_set_drvdata(&op->dev, p); 624 cpwd_device = p; 625 err = 0; 626 627out: 628 return err; 629 630out_unregister: 631 for (i--; i >= 0; i--) 632 misc_deregister(&p->devs[i].misc); 633 634out_iounmap: 635 of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ); 636 637out_free: 638 kfree(p); 639 goto out; 640} 641 642static int __devexit cpwd_remove(struct platform_device *op) 643{ 644 struct cpwd *p = dev_get_drvdata(&op->dev); 645 int i; 646 647 for (i = 0; i < 4; i++) { 648 misc_deregister(&p->devs[i].misc); 649 650 if (!p->enabled) { 651 cpwd_stoptimer(p, i); 652 if (p->devs[i].runstatus & WD_STAT_BSTOP) 653 cpwd_resetbrokentimer(p, i); 654 } 655 } 656 657 if (p->broken) 658 del_timer_sync(&cpwd_timer); 659 660 if (p->initialized) 661 free_irq(p->irq, p); 662 663 of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ); 664 kfree(p); 665 666 cpwd_device = NULL; 667 668 return 0; 669} 670 671static const struct of_device_id cpwd_match[] = { 672 { 673 .name = "watchdog", 674 }, 675 {}, 676}; 677MODULE_DEVICE_TABLE(of, cpwd_match); 678 679static struct of_platform_driver cpwd_driver = { 680 .driver = { 681 .name = DRIVER_NAME, 682 .owner = THIS_MODULE, 683 .of_match_table = cpwd_match, 684 }, 685 .probe = cpwd_probe, 686 .remove = __devexit_p(cpwd_remove), 687}; 688 689static int __init cpwd_init(void) 690{ 691 return of_register_platform_driver(&cpwd_driver); 692} 693 694static void __exit cpwd_exit(void) 695{ 696 of_unregister_platform_driver(&cpwd_driver); 697} 698 699module_init(cpwd_init); 700module_exit(cpwd_exit); 701