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