drivers/char/hpet.c

   1 /*
   2  * Intel & MS High Precision Event Timer Implementation.
   3  *
   4  * Copyright (C) 2003 Intel Corporation
   5  *      Venki Pallipadi
   6  * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
   7  *      Bob Picco <robert.picco@hp.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/config.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/types.h>
  19 #include <linux/miscdevice.h>
  20 #include <linux/major.h>
  21 #include <linux/ioport.h>
  22 #include <linux/fcntl.h>
  23 #include <linux/init.h>
  24 #include <linux/poll.h>
  25 #include <linux/proc_fs.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/wait.h>
  29 #include <linux/bcd.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/bitops.h>
  32
  33 #include <asm/current.h>
  34 #include <asm/uaccess.h>
  35 #include <asm/system.h>
  36 #include <asm/io.h>
  37 #include <asm/irq.h>
  38 #include <asm/div64.h>
  39
  40 #include <linux/acpi.h>
  41 #include <acpi/acpi_bus.h>
  42 #include <linux/hpet.h>
  43
  44 /*
  45  * The High Precision Event Timer driver.
  46  * This driver is closely modelled after the rtc.c driver.
  47  * http://www.intel.com/labs/platcomp/hpet/hpetspec.htm
  48  */
  49 #define HPET_USER_FREQ  (64)
  50 #define HPET_DRIFT      (500)
  51
  52 static u32 hpet_ntimer, hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  53
  54 /* A lock for concurrent access by app and isr hpet activity. */
  55 static DEFINE_SPINLOCK(hpet_lock);
  56 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
  57 static DEFINE_SPINLOCK(hpet_task_lock);
  58
  59 #define HPET_DEV_NAME   (7)
  60
  61 struct hpet_dev {
  62         struct hpets *hd_hpets;
  63         struct hpet __iomem *hd_hpet;
  64         struct hpet_timer __iomem *hd_timer;
  65         unsigned long hd_ireqfreq;
  66         unsigned long hd_irqdata;
  67         wait_queue_head_t hd_waitqueue;
  68         struct fasync_struct *hd_async_queue;
  69         struct hpet_task *hd_task;
  70         unsigned int hd_flags;
  71         unsigned int hd_irq;
  72         unsigned int hd_hdwirq;
  73         char hd_name[HPET_DEV_NAME];
  74 };
  75
  76 struct hpets {
  77         struct hpets *hp_next;
  78         struct hpet __iomem *hp_hpet;
  79         struct time_interpolator *hp_interpolator;
  80         unsigned long hp_period;
  81         unsigned long hp_delta;
  82         unsigned int hp_ntimer;
  83         unsigned int hp_which;
  84         struct hpet_dev hp_dev[1];
  85 };
  86
  87 static struct hpets *hpets;
  88
  89 #define HPET_OPEN               0x0001
  90 #define HPET_IE                 0x0002  /* interrupt enabled */
  91 #define HPET_PERIODIC           0x0004
  92
  93 #if BITS_PER_LONG == 64
  94 #define write_counter(V, MC)    writeq(V, MC)
  95 #define read_counter(MC)        readq(MC)
  96 #else
  97 #define write_counter(V, MC)    writel(V, MC)
  98 #define read_counter(MC)        readl(MC)
  99 #endif
 100
 101 #ifndef readq
 102 static unsigned long long __inline readq(void __iomem *addr)
 103 {
 104         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 105 }
 106 #endif
 107
 108 #ifndef writeq
 109 static void __inline writeq(unsigned long long v, void __iomem *addr)
 110 {
 111         writel(v & 0xffffffff, addr);
 112         writel(v >> 32, addr + 4);
 113 }
 114 #endif
 115
 116 static irqreturn_t hpet_interrupt(int irq, void *data, struct pt_regs *regs)
 117 {
 118         struct hpet_dev *devp;
 119         unsigned long isr;
 120
 121         devp = data;
 122
 123         spin_lock(&hpet_lock);
 124         devp->hd_irqdata++;
 125
 126         /*
 127          * For non-periodic timers, increment the accumulator.
 128          * This has the effect of treating non-periodic like periodic.
 129          */
 130         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 131                 unsigned long m, t;
 132
 133                 t = devp->hd_ireqfreq;
 134                 m = read_counter(&devp->hd_hpet->hpet_mc);
 135                 write_counter(t + m + devp->hd_hpets->hp_delta,
 136                               &devp->hd_timer->hpet_compare);
 137         }
 138
 139         isr = (1 << (devp - devp->hd_hpets->hp_dev));
 140         writeq(isr, &devp->hd_hpet->hpet_isr);
 141         spin_unlock(&hpet_lock);
 142
 143         spin_lock(&hpet_task_lock);
 144         if (devp->hd_task)
 145                 devp->hd_task->ht_func(devp->hd_task->ht_data);
 146         spin_unlock(&hpet_task_lock);
 147
 148         wake_up_interruptible(&devp->hd_waitqueue);
 149
 150         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 151
 152         return IRQ_HANDLED;
 153 }
 154
 155 static int hpet_open(struct inode *inode, struct file *file)
 156 {
 157         struct hpet_dev *devp;
 158         struct hpets *hpetp;
 159         int i;
 160
 161         if (file->f_mode & FMODE_WRITE)
 162                 return -EINVAL;
 163
 164         spin_lock_irq(&hpet_lock);
 165
 166         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 167                 for (i = 0; i < hpetp->hp_ntimer; i++)
 168                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
 169                             || hpetp->hp_dev[i].hd_task)
 170                                 continue;
 171                         else {
 172                                 devp = &hpetp->hp_dev[i];
 173                                 break;
 174                         }
 175
 176         if (!devp) {
 177                 spin_unlock_irq(&hpet_lock);
 178                 return -EBUSY;
 179         }
 180
 181         file->private_data = devp;
 182         devp->hd_irqdata = 0;
 183         devp->hd_flags |= HPET_OPEN;
 184         spin_unlock_irq(&hpet_lock);
 185
 186         return 0;
 187 }
 188
 189 static ssize_t
 190 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 191 {
 192         DECLARE_WAITQUEUE(wait, current);
 193         unsigned long data;
 194         ssize_t retval;
 195         struct hpet_dev *devp;
 196
 197         devp = file->private_data;
 198         if (!devp->hd_ireqfreq)
 199                 return -EIO;
 200
 201         if (count < sizeof(unsigned long))
 202                 return -EINVAL;
 203
 204         add_wait_queue(&devp->hd_waitqueue, &wait);
 205
 206         for ( ; ; ) {
 207                 set_current_state(TASK_INTERRUPTIBLE);
 208
 209                 spin_lock_irq(&hpet_lock);
 210                 data = devp->hd_irqdata;
 211                 devp->hd_irqdata = 0;
 212                 spin_unlock_irq(&hpet_lock);
 213
 214                 if (data)
 215                         break;
 216                 else if (file->f_flags & O_NONBLOCK) {
 217                         retval = -EAGAIN;
 218                         goto out;
 219                 } else if (signal_pending(current)) {
 220                         retval = -ERESTARTSYS;
 221                         goto out;
 222                 }
 223                 schedule();
 224         }
 225
 226         retval = put_user(data, (unsigned long __user *)buf);
 227         if (!retval)
 228                 retval = sizeof(unsigned long);
 229 out:
 230         __set_current_state(TASK_RUNNING);
 231         remove_wait_queue(&devp->hd_waitqueue, &wait);
 232
 233         return retval;
 234 }
 235
 236 static unsigned int hpet_poll(struct file *file, poll_table * wait)
 237 {
 238         unsigned long v;
 239         struct hpet_dev *devp;
 240
 241         devp = file->private_data;
 242
 243         if (!devp->hd_ireqfreq)
 244                 return 0;
 245
 246         poll_wait(file, &devp->hd_waitqueue, wait);
 247
 248         spin_lock_irq(&hpet_lock);
 249         v = devp->hd_irqdata;
 250         spin_unlock_irq(&hpet_lock);
 251
 252         if (v != 0)
 253                 return POLLIN | POLLRDNORM;
 254
 255         return 0;
 256 }
 257
 258 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 259 {
 260 #ifdef  CONFIG_HPET_MMAP
 261         struct hpet_dev *devp;
 262         unsigned long addr;
 263
 264         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
 265                 return -EINVAL;
 266
 267         devp = file->private_data;
 268         addr = (unsigned long)devp->hd_hpet;
 269
 270         if (addr & (PAGE_SIZE - 1))
 271                 return -ENOSYS;
 272
 273         vma->vm_flags |= VM_IO;
 274         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 275         addr = __pa(addr);
 276
 277         if (remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
 278                                         PAGE_SIZE, vma->vm_page_prot)) {
 279                 printk(KERN_ERR "remap_pfn_range failed in hpet.c\n");
 280                 return -EAGAIN;
 281         }
 282
 283         return 0;
 284 #else
 285         return -ENOSYS;
 286 #endif
 287 }
 288
 289 static int hpet_fasync(int fd, struct file *file, int on)
 290 {
 291         struct hpet_dev *devp;
 292
 293         devp = file->private_data;
 294
 295         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 296                 return 0;
 297         else
 298                 return -EIO;
 299 }
 300
 301 static int hpet_release(struct inode *inode, struct file *file)
 302 {
 303         struct hpet_dev *devp;
 304         struct hpet_timer __iomem *timer;
 305         int irq = 0;
 306
 307         devp = file->private_data;
 308         timer = devp->hd_timer;
 309
 310         spin_lock_irq(&hpet_lock);
 311
 312         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 313                &timer->hpet_config);
 314
 315         irq = devp->hd_irq;
 316         devp->hd_irq = 0;
 317
 318         devp->hd_ireqfreq = 0;
 319
 320         if (devp->hd_flags & HPET_PERIODIC
 321             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 322                 unsigned long v;
 323
 324                 v = readq(&timer->hpet_config);
 325                 v ^= Tn_TYPE_CNF_MASK;
 326                 writeq(v, &timer->hpet_config);
 327         }
 328
 329         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 330         spin_unlock_irq(&hpet_lock);
 331
 332         if (irq)
 333                 free_irq(irq, devp);
 334
 335         if (file->f_flags & FASYNC)
 336                 hpet_fasync(-1, file, 0);
 337
 338         file->private_data = NULL;
 339         return 0;
 340 }
 341
 342 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
 343
 344 static int
 345 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 346            unsigned long arg)
 347 {
 348         struct hpet_dev *devp;
 349
 350         devp = file->private_data;
 351         return hpet_ioctl_common(devp, cmd, arg, 0);
 352 }
 353
 354 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 355 {
 356         struct hpet_timer __iomem *timer;
 357         struct hpet __iomem *hpet;
 358         struct hpets *hpetp;
 359         int irq;
 360         unsigned long g, v, t, m;
 361         unsigned long flags, isr;
 362
 363         timer = devp->hd_timer;
 364         hpet = devp->hd_hpet;
 365         hpetp = devp->hd_hpets;
 366
 367         v = readq(&timer->hpet_config);
 368         spin_lock_irq(&hpet_lock);
 369
 370         if (devp->hd_flags & HPET_IE) {
 371                 spin_unlock_irq(&hpet_lock);
 372                 return -EBUSY;
 373         }
 374
 375         devp->hd_flags |= HPET_IE;
 376         spin_unlock_irq(&hpet_lock);
 377
 378         t = readq(&timer->hpet_config);
 379         irq = devp->hd_hdwirq;
 380
 381         if (irq) {
 382                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 383
 384                 if (request_irq
 385                     (irq, hpet_interrupt, SA_INTERRUPT, devp->hd_name, (void *)devp)) {
 386                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 387                         irq = 0;
 388                 }
 389         }
 390
 391         if (irq == 0) {
 392                 spin_lock_irq(&hpet_lock);
 393                 devp->hd_flags ^= HPET_IE;
 394                 spin_unlock_irq(&hpet_lock);
 395                 return -EIO;
 396         }
 397
 398         devp->hd_irq = irq;
 399         t = devp->hd_ireqfreq;
 400         v = readq(&timer->hpet_config);
 401         g = v | Tn_INT_ENB_CNF_MASK;
 402
 403         if (devp->hd_flags & HPET_PERIODIC) {
 404                 write_counter(t, &timer->hpet_compare);
 405                 g |= Tn_TYPE_CNF_MASK;
 406                 v |= Tn_TYPE_CNF_MASK;
 407                 writeq(v, &timer->hpet_config);
 408                 v |= Tn_VAL_SET_CNF_MASK;
 409                 writeq(v, &timer->hpet_config);
 410                 local_irq_save(flags);
 411                 m = read_counter(&hpet->hpet_mc);
 412                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 413         } else {
 414                 local_irq_save(flags);
 415                 m = read_counter(&hpet->hpet_mc);
 416                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 417         }
 418
 419         isr = (1 << (devp - hpets->hp_dev));
 420         writeq(isr, &hpet->hpet_isr);
 421         writeq(g, &timer->hpet_config);
 422         local_irq_restore(flags);
 423
 424         return 0;
 425 }
 426
 427 static inline unsigned long hpet_time_div(unsigned long dis)
 428 {
 429         unsigned long long m = 1000000000000000ULL;
 430
 431         do_div(m, dis);
 432
 433         return (unsigned long)m;
 434 }
 435
 436 static int
 437 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
 438 {
 439         struct hpet_timer __iomem *timer;
 440         struct hpet __iomem *hpet;
 441         struct hpets *hpetp;
 442         int err;
 443         unsigned long v;
 444
 445         switch (cmd) {
 446         case HPET_IE_OFF:
 447         case HPET_INFO:
 448         case HPET_EPI:
 449         case HPET_DPI:
 450         case HPET_IRQFREQ:
 451                 timer = devp->hd_timer;
 452                 hpet = devp->hd_hpet;
 453                 hpetp = devp->hd_hpets;
 454                 break;
 455         case HPET_IE_ON:
 456                 return hpet_ioctl_ieon(devp);
 457         default:
 458                 return -EINVAL;
 459         }
 460
 461         err = 0;
 462
 463         switch (cmd) {
 464         case HPET_IE_OFF:
 465                 if ((devp->hd_flags & HPET_IE) == 0)
 466                         break;
 467                 v = readq(&timer->hpet_config);
 468                 v &= ~Tn_INT_ENB_CNF_MASK;
 469                 writeq(v, &timer->hpet_config);
 470                 if (devp->hd_irq) {
 471                         free_irq(devp->hd_irq, devp);
 472                         devp->hd_irq = 0;
 473                 }
 474                 devp->hd_flags ^= HPET_IE;
 475                 break;
 476         case HPET_INFO:
 477                 {
 478                         struct hpet_info info;
 479
 480                         info.hi_ireqfreq = hpet_time_div(hpetp->hp_period *
 481                                                          devp->hd_ireqfreq);
 482                         info.hi_flags =
 483                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 484                         info.hi_hpet = devp->hd_hpets->hp_which;
 485                         info.hi_timer = devp - devp->hd_hpets->hp_dev;
 486                         if (copy_to_user((void __user *)arg, &info, sizeof(info)))
 487                                 err = -EFAULT;
 488                         break;
 489                 }
 490         case HPET_EPI:
 491                 v = readq(&timer->hpet_config);
 492                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 493                         err = -ENXIO;
 494                         break;
 495                 }
 496                 devp->hd_flags |= HPET_PERIODIC;
 497                 break;
 498         case HPET_DPI:
 499                 v = readq(&timer->hpet_config);
 500                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 501                         err = -ENXIO;
 502                         break;
 503                 }
 504                 if (devp->hd_flags & HPET_PERIODIC &&
 505                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 506                         v = readq(&timer->hpet_config);
 507                         v ^= Tn_TYPE_CNF_MASK;
 508                         writeq(v, &timer->hpet_config);
 509                 }
 510                 devp->hd_flags &= ~HPET_PERIODIC;
 511                 break;
 512         case HPET_IRQFREQ:
 513                 if (!kernel && (arg > hpet_max_freq) &&
 514                     !capable(CAP_SYS_RESOURCE)) {
 515                         err = -EACCES;
 516                         break;
 517                 }
 518
 519                 if (arg & (arg - 1)) {
 520                         err = -EINVAL;
 521                         break;
 522                 }
 523
 524                 devp->hd_ireqfreq = hpet_time_div(hpetp->hp_period * arg);
 525         }
 526
 527         return err;
 528 }
 529
 530 static struct file_operations hpet_fops = {
 531         .owner = THIS_MODULE,
 532         .llseek = no_llseek,
 533         .read = hpet_read,
 534         .poll = hpet_poll,
 535         .ioctl = hpet_ioctl,
 536         .open = hpet_open,
 537         .release = hpet_release,
 538         .fasync = hpet_fasync,
 539         .mmap = hpet_mmap,
 540 };
 541
 542 EXPORT_SYMBOL(hpet_alloc);
 543 EXPORT_SYMBOL(hpet_register);
 544 EXPORT_SYMBOL(hpet_unregister);
 545 EXPORT_SYMBOL(hpet_control);
 546
 547 int hpet_register(struct hpet_task *tp, int periodic)
 548 {
 549         unsigned int i;
 550         u64 mask;
 551         struct hpet_timer __iomem *timer;
 552         struct hpet_dev *devp;
 553         struct hpets *hpetp;
 554
 555         switch (periodic) {
 556         case 1:
 557                 mask = Tn_PER_INT_CAP_MASK;
 558                 break;
 559         case 0:
 560                 mask = 0;
 561                 break;
 562         default:
 563                 return -EINVAL;
 564         }
 565
 566         spin_lock_irq(&hpet_task_lock);
 567         spin_lock(&hpet_lock);
 568
 569         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 570                 for (timer = hpetp->hp_hpet->hpet_timers, i = 0;
 571                      i < hpetp->hp_ntimer; i++, timer++) {
 572                         if ((readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK)
 573                             != mask)
 574                                 continue;
 575
 576                         devp = &hpetp->hp_dev[i];
 577
 578                         if (devp->hd_flags & HPET_OPEN || devp->hd_task) {
 579                                 devp = NULL;
 580                                 continue;
 581                         }
 582
 583                         tp->ht_opaque = devp;
 584                         devp->hd_task = tp;
 585                         break;
 586                 }
 587
 588         spin_unlock(&hpet_lock);
 589         spin_unlock_irq(&hpet_task_lock);
 590
 591         if (tp->ht_opaque)
 592                 return 0;
 593         else
 594                 return -EBUSY;
 595 }
 596
 597 static inline int hpet_tpcheck(struct hpet_task *tp)
 598 {
 599         struct hpet_dev *devp;
 600         struct hpets *hpetp;
 601
 602         devp = tp->ht_opaque;
 603
 604         if (!devp)
 605                 return -ENXIO;
 606
 607         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 608                 if (devp >= hpetp->hp_dev
 609                     && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
 610                     && devp->hd_hpet == hpetp->hp_hpet)
 611                         return 0;
 612
 613         return -ENXIO;
 614 }
 615
 616 int hpet_unregister(struct hpet_task *tp)
 617 {
 618         struct hpet_dev *devp;
 619         struct hpet_timer __iomem *timer;
 620         int err;
 621
 622         if ((err = hpet_tpcheck(tp)))
 623                 return err;
 624
 625         spin_lock_irq(&hpet_task_lock);
 626         spin_lock(&hpet_lock);
 627
 628         devp = tp->ht_opaque;
 629         if (devp->hd_task != tp) {
 630                 spin_unlock(&hpet_lock);
 631                 spin_unlock_irq(&hpet_task_lock);
 632                 return -ENXIO;
 633         }
 634
 635         timer = devp->hd_timer;
 636         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 637                &timer->hpet_config);
 638         devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
 639         devp->hd_task = NULL;
 640         spin_unlock(&hpet_lock);
 641         spin_unlock_irq(&hpet_task_lock);
 642
 643         return 0;
 644 }
 645
 646 int hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
 647 {
 648         struct hpet_dev *devp;
 649         int err;
 650
 651         if ((err = hpet_tpcheck(tp)))
 652                 return err;
 653
 654         spin_lock_irq(&hpet_lock);
 655         devp = tp->ht_opaque;
 656         if (devp->hd_task != tp) {
 657                 spin_unlock_irq(&hpet_lock);
 658                 return -ENXIO;
 659         }
 660         spin_unlock_irq(&hpet_lock);
 661         return hpet_ioctl_common(devp, cmd, arg, 1);
 662 }
 663
 664 static ctl_table hpet_table[] = {
 665         {
 666          .ctl_name = 1,
 667          .procname = "max-user-freq",
 668          .data = &hpet_max_freq,
 669          .maxlen = sizeof(int),
 670          .mode = 0644,
 671          .proc_handler = &proc_dointvec,
 672          },
 673         {.ctl_name = 0}
 674 };
 675
 676 static ctl_table hpet_root[] = {
 677         {
 678          .ctl_name = 1,
 679          .procname = "hpet",
 680          .maxlen = 0,
 681          .mode = 0555,
 682          .child = hpet_table,
 683          },
 684         {.ctl_name = 0}
 685 };
 686
 687 static ctl_table dev_root[] = {
 688         {
 689          .ctl_name = CTL_DEV,
 690          .procname = "dev",
 691          .maxlen = 0,
 692          .mode = 0555,
 693          .child = hpet_root,
 694          },
 695         {.ctl_name = 0}
 696 };
 697
 698 static struct ctl_table_header *sysctl_header;
 699
 700 static void hpet_register_interpolator(struct hpets *hpetp)
 701 {
 702 #ifdef  CONFIG_TIME_INTERPOLATION
 703         struct time_interpolator *ti;
 704
 705         ti = kmalloc(sizeof(*ti), GFP_KERNEL);
 706         if (!ti)
 707                 return;
 708
 709         memset(ti, 0, sizeof(*ti));
 710         ti->source = TIME_SOURCE_MMIO64;
 711         ti->shift = 10;
 712         ti->addr = &hpetp->hp_hpet->hpet_mc;
 713         ti->frequency = hpet_time_div(hpets->hp_period);
 714         ti->drift = ti->frequency * HPET_DRIFT / 1000000;
 715         ti->mask = -1;
 716
 717         hpetp->hp_interpolator = ti;
 718         register_time_interpolator(ti);
 719 #endif
 720 }
 721
 722 /*
 723  * Adjustment for when arming the timer with
 724  * initial conditions.  That is, main counter
 725  * ticks expired before interrupts are enabled.
 726  */
 727 #define TICK_CALIBRATE  (1000UL)
 728
 729 static unsigned long hpet_calibrate(struct hpets *hpetp)
 730 {
 731         struct hpet_timer __iomem *timer = NULL;
 732         unsigned long t, m, count, i, flags, start;
 733         struct hpet_dev *devp;
 734         int j;
 735         struct hpet __iomem *hpet;
 736
 737         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 738                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 739                         timer = devp->hd_timer;
 740                         break;
 741                 }
 742
 743         if (!timer)
 744                 return 0;
 745
 746         hpet = hpets->hp_hpet;
 747         t = read_counter(&timer->hpet_compare);
 748
 749         i = 0;
 750         count = hpet_time_div(hpetp->hp_period * TICK_CALIBRATE);
 751
 752         local_irq_save(flags);
 753
 754         start = read_counter(&hpet->hpet_mc);
 755
 756         do {
 757                 m = read_counter(&hpet->hpet_mc);
 758                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 759         } while (i++, (m - start) < count);
 760
 761         local_irq_restore(flags);
 762
 763         return (m - start) / i;
 764 }
 765
 766 int hpet_alloc(struct hpet_data *hdp)
 767 {
 768         u64 cap, mcfg;
 769         struct hpet_dev *devp;
 770         u32 i, ntimer;
 771         struct hpets *hpetp;
 772         size_t siz;
 773         struct hpet __iomem *hpet;
 774         static struct hpets *last = (struct hpets *)0;
 775         unsigned long ns;
 776
 777         /*
 778          * hpet_alloc can be called by platform dependent code.
 779          * if platform dependent code has allocated the hpet
 780          * ACPI also reports hpet, then we catch it here.
 781          */
 782         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 783                 if (hpetp->hp_hpet == hdp->hd_address)
 784                         return 0;
 785
 786         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 787                                       sizeof(struct hpet_dev));
 788
 789         hpetp = kmalloc(siz, GFP_KERNEL);
 790
 791         if (!hpetp)
 792                 return -ENOMEM;
 793
 794         memset(hpetp, 0, siz);
 795
 796         hpetp->hp_which = hpet_nhpet++;
 797         hpetp->hp_hpet = hdp->hd_address;
 798
 799         hpetp->hp_ntimer = hdp->hd_nirqs;
 800
 801         for (i = 0; i < hdp->hd_nirqs; i++)
 802                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 803
 804         hpet = hpetp->hp_hpet;
 805
 806         cap = readq(&hpet->hpet_cap);
 807
 808         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 809
 810         if (hpetp->hp_ntimer != ntimer) {
 811                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 812                        " with number of timers\n");
 813                 kfree(hpetp);
 814                 return -ENODEV;
 815         }
 816
 817         if (last)
 818                 last->hp_next = hpetp;
 819         else
 820                 hpets = hpetp;
 821
 822         last = hpetp;
 823
 824         hpetp->hp_period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 825             HPET_COUNTER_CLK_PERIOD_SHIFT;
 826
 827         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 828                 hpetp->hp_which, hdp->hd_phys_address,
 829                 hpetp->hp_ntimer > 1 ? "s" : "");
 830         for (i = 0; i < hpetp->hp_ntimer; i++)
 831                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 832         printk("\n");
 833
 834         ns = hpetp->hp_period;  /* femptoseconds, 10^-15 */
 835         do_div(ns, 1000000);    /* convert to nanoseconds, 10^-9 */
 836         printk(KERN_INFO "hpet%d: %ldns tick, %d %d-bit timers\n",
 837                 hpetp->hp_which, ns, hpetp->hp_ntimer,
 838                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32);
 839
 840         mcfg = readq(&hpet->hpet_config);
 841         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 842                 write_counter(0L, &hpet->hpet_mc);
 843                 mcfg |= HPET_ENABLE_CNF_MASK;
 844                 writeq(mcfg, &hpet->hpet_config);
 845         }
 846
 847         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer;
 848              i++, hpet_ntimer++, devp++) {
 849                 unsigned long v;
 850                 struct hpet_timer __iomem *timer;
 851
 852                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 853                 v = readq(&timer->hpet_config);
 854
 855                 devp->hd_hpets = hpetp;
 856                 devp->hd_hpet = hpet;
 857                 devp->hd_timer = timer;
 858
 859                 /*
 860                  * If the timer was reserved by platform code,
 861                  * then make timer unavailable for opens.
 862                  */
 863                 if (hdp->hd_state & (1 << i)) {
 864                         devp->hd_flags = HPET_OPEN;
 865                         continue;
 866                 }
 867
 868                 init_waitqueue_head(&devp->hd_waitqueue);
 869         }
 870
 871         hpetp->hp_delta = hpet_calibrate(hpetp);
 872         hpet_register_interpolator(hpetp);
 873
 874         return 0;
 875 }
 876
 877 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 878 {
 879         struct hpet_data *hdp;
 880         acpi_status status;
 881         struct acpi_resource_address64 addr;
 882         struct hpets *hpetp;
 883
 884         hdp = data;
 885
 886         status = acpi_resource_to_address64(res, &addr);
 887
 888         if (ACPI_SUCCESS(status)) {
 889                 unsigned long size;
 890
 891                 size = addr.max_address_range - addr.min_address_range + 1;
 892                 hdp->hd_phys_address = addr.min_address_range;
 893                 hdp->hd_address = ioremap(addr.min_address_range, size);
 894
 895                 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 896                         if (hpetp->hp_hpet == hdp->hd_address)
 897                                 return -EBUSY;
 898         } else if (res->id == ACPI_RSTYPE_EXT_IRQ) {
 899                 struct acpi_resource_ext_irq *irqp;
 900                 int i;
 901
 902                 irqp = &res->data.extended_irq;
 903
 904                 if (irqp->number_of_interrupts > 0) {
 905                         hdp->hd_nirqs = irqp->number_of_interrupts;
 906
 907                         for (i = 0; i < hdp->hd_nirqs; i++)
 908                                 hdp->hd_irq[i] =
 909                                     acpi_register_gsi(irqp->interrupts[i],
 910                                                       irqp->edge_level,
 911                                                       irqp->active_high_low);
 912                 }
 913         }
 914
 915         return AE_OK;
 916 }
 917
 918 static int hpet_acpi_add(struct acpi_device *device)
 919 {
 920         acpi_status result;
 921         struct hpet_data data;
 922
 923         memset(&data, 0, sizeof(data));
 924
 925         result =
 926             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 927                                 hpet_resources, &data);
 928
 929         if (ACPI_FAILURE(result))
 930                 return -ENODEV;
 931
 932         if (!data.hd_address || !data.hd_nirqs) {
 933                 printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
 934                 return -ENODEV;
 935         }
 936
 937         return hpet_alloc(&data);
 938 }
 939
 940 static int hpet_acpi_remove(struct acpi_device *device, int type)
 941 {
 942         /* XXX need to unregister interpolator, dealloc mem, etc */
 943         return -EINVAL;
 944 }
 945
 946 static struct acpi_driver hpet_acpi_driver = {
 947         .name = "hpet",
 948         .ids = "PNP0103",
 949         .ops = {
 950                 .add = hpet_acpi_add,
 951                 .remove = hpet_acpi_remove,
 952                 },
 953 };
 954
 955 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
 956
 957 static int __init hpet_init(void)
 958 {
 959         int result;
 960
 961         result = misc_register(&hpet_misc);
 962         if (result < 0)
 963                 return -ENODEV;
 964
 965         sysctl_header = register_sysctl_table(dev_root, 0);
 966
 967         result = acpi_bus_register_driver(&hpet_acpi_driver);
 968         if (result < 0) {
 969                 if (sysctl_header)
 970                         unregister_sysctl_table(sysctl_header);
 971                 misc_deregister(&hpet_misc);
 972                 return result;
 973         }
 974
 975         return 0;
 976 }
 977
 978 static void __exit hpet_exit(void)
 979 {
 980         acpi_bus_unregister_driver(&hpet_acpi_driver);
 981
 982         if (sysctl_header)
 983                 unregister_sysctl_table(sysctl_header);
 984         misc_deregister(&hpet_misc);
 985
 986         return;
 987 }
 988
 989 module_init(hpet_init);
 990 module_exit(hpet_exit);
 991 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
 992 MODULE_LICENSE("GPL");