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/interrupt.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/types.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/major.h>
  20 #include <linux/ioport.h>
  21 #include <linux/fcntl.h>
  22 #include <linux/init.h>
  23 #include <linux/poll.h>
  24 #include <linux/mm.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 #include <linux/clocksource.h>
  33
  34 #include <asm/current.h>
  35 #include <asm/uaccess.h>
  36 #include <asm/system.h>
  37 #include <asm/io.h>
  38 #include <asm/irq.h>
  39 #include <asm/div64.h>
  40
  41 #include <linux/acpi.h>
  42 #include <acpi/acpi_bus.h>
  43 #include <linux/hpet.h>
  44
  45 /*
  46  * The High Precision Event Timer driver.
  47  * This driver is closely modelled after the rtc.c driver.
  48  * http://www.intel.com/hardwaredesign/hpetspec.htm
  49  */
  50 #define HPET_USER_FREQ  (64)
  51 #define HPET_DRIFT      (500)
  52
  53 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
  54
  55 #if BITS_PER_LONG == 64
  56 #define write_counter(V, MC)    writeq(V, MC)
  57 #define read_counter(MC)        readq(MC)
  58 #else
  59 #define write_counter(V, MC)    writel(V, MC)
  60 #define read_counter(MC)        readl(MC)
  61 #endif
  62
  63 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  64
  65 /* This clocksource driver currently only works on ia64 */
  66 #ifdef CONFIG_IA64
  67 static void __iomem *hpet_mctr;
  68
  69 static cycle_t read_hpet(void)
  70 {
  71         return (cycle_t)read_counter((void __iomem *)hpet_mctr);
  72 }
  73
  74 static struct clocksource clocksource_hpet = {
  75         .name           = "hpet",
  76         .rating         = 250,
  77         .read           = read_hpet,
  78         .mask           = CLOCKSOURCE_MASK(64),
  79         .mult           = 0, /*to be caluclated*/
  80         .shift          = 10,
  81         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  82 };
  83 static struct clocksource *hpet_clocksource;
  84 #endif
  85
  86 /* A lock for concurrent access by app and isr hpet activity. */
  87 static DEFINE_SPINLOCK(hpet_lock);
  88 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
  89 static DEFINE_SPINLOCK(hpet_task_lock);
  90
  91 #define HPET_DEV_NAME   (7)
  92
  93 struct hpet_dev {
  94         struct hpets *hd_hpets;
  95         struct hpet __iomem *hd_hpet;
  96         struct hpet_timer __iomem *hd_timer;
  97         unsigned long hd_ireqfreq;
  98         unsigned long hd_irqdata;
  99         wait_queue_head_t hd_waitqueue;
 100         struct fasync_struct *hd_async_queue;
 101         struct hpet_task *hd_task;
 102         unsigned int hd_flags;
 103         unsigned int hd_irq;
 104         unsigned int hd_hdwirq;
 105         char hd_name[HPET_DEV_NAME];
 106 };
 107
 108 struct hpets {
 109         struct hpets *hp_next;
 110         struct hpet __iomem *hp_hpet;
 111         unsigned long hp_hpet_phys;
 112         struct clocksource *hp_clocksource;
 113         unsigned long long hp_tick_freq;
 114         unsigned long hp_delta;
 115         unsigned int hp_ntimer;
 116         unsigned int hp_which;
 117         struct hpet_dev hp_dev[1];
 118 };
 119
 120 static struct hpets *hpets;
 121
 122 #define HPET_OPEN               0x0001
 123 #define HPET_IE                 0x0002  /* interrupt enabled */
 124 #define HPET_PERIODIC           0x0004
 125 #define HPET_SHARED_IRQ         0x0008
 126
 127
 128 #ifndef readq
 129 static inline unsigned long long readq(void __iomem *addr)
 130 {
 131         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 132 }
 133 #endif
 134
 135 #ifndef writeq
 136 static inline void writeq(unsigned long long v, void __iomem *addr)
 137 {
 138         writel(v & 0xffffffff, addr);
 139         writel(v >> 32, addr + 4);
 140 }
 141 #endif
 142
 143 static irqreturn_t hpet_interrupt(int irq, void *data)
 144 {
 145         struct hpet_dev *devp;
 146         unsigned long isr;
 147
 148         devp = data;
 149         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 150
 151         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 152             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 153                 return IRQ_NONE;
 154
 155         spin_lock(&hpet_lock);
 156         devp->hd_irqdata++;
 157
 158         /*
 159          * For non-periodic timers, increment the accumulator.
 160          * This has the effect of treating non-periodic like periodic.
 161          */
 162         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 163                 unsigned long m, t;
 164
 165                 t = devp->hd_ireqfreq;
 166                 m = read_counter(&devp->hd_hpet->hpet_mc);
 167                 write_counter(t + m + devp->hd_hpets->hp_delta,
 168                               &devp->hd_timer->hpet_compare);
 169         }
 170
 171         if (devp->hd_flags & HPET_SHARED_IRQ)
 172                 writel(isr, &devp->hd_hpet->hpet_isr);
 173         spin_unlock(&hpet_lock);
 174
 175         spin_lock(&hpet_task_lock);
 176         if (devp->hd_task)
 177                 devp->hd_task->ht_func(devp->hd_task->ht_data);
 178         spin_unlock(&hpet_task_lock);
 179
 180         wake_up_interruptible(&devp->hd_waitqueue);
 181
 182         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 183
 184         return IRQ_HANDLED;
 185 }
 186
 187 static int hpet_open(struct inode *inode, struct file *file)
 188 {
 189         struct hpet_dev *devp;
 190         struct hpets *hpetp;
 191         int i;
 192
 193         if (file->f_mode & FMODE_WRITE)
 194                 return -EINVAL;
 195
 196         spin_lock_irq(&hpet_lock);
 197
 198         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 199                 for (i = 0; i < hpetp->hp_ntimer; i++)
 200                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
 201                             || hpetp->hp_dev[i].hd_task)
 202                                 continue;
 203                         else {
 204                                 devp = &hpetp->hp_dev[i];
 205                                 break;
 206                         }
 207
 208         if (!devp) {
 209                 spin_unlock_irq(&hpet_lock);
 210                 return -EBUSY;
 211         }
 212
 213         file->private_data = devp;
 214         devp->hd_irqdata = 0;
 215         devp->hd_flags |= HPET_OPEN;
 216         spin_unlock_irq(&hpet_lock);
 217
 218         return 0;
 219 }
 220
 221 static ssize_t
 222 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 223 {
 224         DECLARE_WAITQUEUE(wait, current);
 225         unsigned long data;
 226         ssize_t retval;
 227         struct hpet_dev *devp;
 228
 229         devp = file->private_data;
 230         if (!devp->hd_ireqfreq)
 231                 return -EIO;
 232
 233         if (count < sizeof(unsigned long))
 234                 return -EINVAL;
 235
 236         add_wait_queue(&devp->hd_waitqueue, &wait);
 237
 238         for ( ; ; ) {
 239                 set_current_state(TASK_INTERRUPTIBLE);
 240
 241                 spin_lock_irq(&hpet_lock);
 242                 data = devp->hd_irqdata;
 243                 devp->hd_irqdata = 0;
 244                 spin_unlock_irq(&hpet_lock);
 245
 246                 if (data)
 247                         break;
 248                 else if (file->f_flags & O_NONBLOCK) {
 249                         retval = -EAGAIN;
 250                         goto out;
 251                 } else if (signal_pending(current)) {
 252                         retval = -ERESTARTSYS;
 253                         goto out;
 254                 }
 255                 schedule();
 256         }
 257
 258         retval = put_user(data, (unsigned long __user *)buf);
 259         if (!retval)
 260                 retval = sizeof(unsigned long);
 261 out:
 262         __set_current_state(TASK_RUNNING);
 263         remove_wait_queue(&devp->hd_waitqueue, &wait);
 264
 265         return retval;
 266 }
 267
 268 static unsigned int hpet_poll(struct file *file, poll_table * wait)
 269 {
 270         unsigned long v;
 271         struct hpet_dev *devp;
 272
 273         devp = file->private_data;
 274
 275         if (!devp->hd_ireqfreq)
 276                 return 0;
 277
 278         poll_wait(file, &devp->hd_waitqueue, wait);
 279
 280         spin_lock_irq(&hpet_lock);
 281         v = devp->hd_irqdata;
 282         spin_unlock_irq(&hpet_lock);
 283
 284         if (v != 0)
 285                 return POLLIN | POLLRDNORM;
 286
 287         return 0;
 288 }
 289
 290 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 291 {
 292 #ifdef  CONFIG_HPET_MMAP
 293         struct hpet_dev *devp;
 294         unsigned long addr;
 295
 296         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
 297                 return -EINVAL;
 298
 299         devp = file->private_data;
 300         addr = devp->hd_hpets->hp_hpet_phys;
 301
 302         if (addr & (PAGE_SIZE - 1))
 303                 return -ENOSYS;
 304
 305         vma->vm_flags |= VM_IO;
 306         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 307
 308         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
 309                                         PAGE_SIZE, vma->vm_page_prot)) {
 310                 printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
 311                         __FUNCTION__);
 312                 return -EAGAIN;
 313         }
 314
 315         return 0;
 316 #else
 317         return -ENOSYS;
 318 #endif
 319 }
 320
 321 static int hpet_fasync(int fd, struct file *file, int on)
 322 {
 323         struct hpet_dev *devp;
 324
 325         devp = file->private_data;
 326
 327         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 328                 return 0;
 329         else
 330                 return -EIO;
 331 }
 332
 333 static int hpet_release(struct inode *inode, struct file *file)
 334 {
 335         struct hpet_dev *devp;
 336         struct hpet_timer __iomem *timer;
 337         int irq = 0;
 338
 339         devp = file->private_data;
 340         timer = devp->hd_timer;
 341
 342         spin_lock_irq(&hpet_lock);
 343
 344         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 345                &timer->hpet_config);
 346
 347         irq = devp->hd_irq;
 348         devp->hd_irq = 0;
 349
 350         devp->hd_ireqfreq = 0;
 351
 352         if (devp->hd_flags & HPET_PERIODIC
 353             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 354                 unsigned long v;
 355
 356                 v = readq(&timer->hpet_config);
 357                 v ^= Tn_TYPE_CNF_MASK;
 358                 writeq(v, &timer->hpet_config);
 359         }
 360
 361         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 362         spin_unlock_irq(&hpet_lock);
 363
 364         if (irq)
 365                 free_irq(irq, devp);
 366
 367         if (file->f_flags & FASYNC)
 368                 hpet_fasync(-1, file, 0);
 369
 370         file->private_data = NULL;
 371         return 0;
 372 }
 373
 374 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
 375
 376 static int
 377 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 378            unsigned long arg)
 379 {
 380         struct hpet_dev *devp;
 381
 382         devp = file->private_data;
 383         return hpet_ioctl_common(devp, cmd, arg, 0);
 384 }
 385
 386 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 387 {
 388         struct hpet_timer __iomem *timer;
 389         struct hpet __iomem *hpet;
 390         struct hpets *hpetp;
 391         int irq;
 392         unsigned long g, v, t, m;
 393         unsigned long flags, isr;
 394
 395         timer = devp->hd_timer;
 396         hpet = devp->hd_hpet;
 397         hpetp = devp->hd_hpets;
 398
 399         if (!devp->hd_ireqfreq)
 400                 return -EIO;
 401
 402         spin_lock_irq(&hpet_lock);
 403
 404         if (devp->hd_flags & HPET_IE) {
 405                 spin_unlock_irq(&hpet_lock);
 406                 return -EBUSY;
 407         }
 408
 409         devp->hd_flags |= HPET_IE;
 410
 411         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 412                 devp->hd_flags |= HPET_SHARED_IRQ;
 413         spin_unlock_irq(&hpet_lock);
 414
 415         irq = devp->hd_hdwirq;
 416
 417         if (irq) {
 418                 unsigned long irq_flags;
 419
 420                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 421                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 422                                                 ? IRQF_SHARED : IRQF_DISABLED;
 423                 if (request_irq(irq, hpet_interrupt, irq_flags,
 424                                 devp->hd_name, (void *)devp)) {
 425                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 426                         irq = 0;
 427                 }
 428         }
 429
 430         if (irq == 0) {
 431                 spin_lock_irq(&hpet_lock);
 432                 devp->hd_flags ^= HPET_IE;
 433                 spin_unlock_irq(&hpet_lock);
 434                 return -EIO;
 435         }
 436
 437         devp->hd_irq = irq;
 438         t = devp->hd_ireqfreq;
 439         v = readq(&timer->hpet_config);
 440         g = v | Tn_INT_ENB_CNF_MASK;
 441
 442         if (devp->hd_flags & HPET_PERIODIC) {
 443                 write_counter(t, &timer->hpet_compare);
 444                 g |= Tn_TYPE_CNF_MASK;
 445                 v |= Tn_TYPE_CNF_MASK;
 446                 writeq(v, &timer->hpet_config);
 447                 v |= Tn_VAL_SET_CNF_MASK;
 448                 writeq(v, &timer->hpet_config);
 449                 local_irq_save(flags);
 450                 m = read_counter(&hpet->hpet_mc);
 451                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 452         } else {
 453                 local_irq_save(flags);
 454                 m = read_counter(&hpet->hpet_mc);
 455                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 456         }
 457
 458         if (devp->hd_flags & HPET_SHARED_IRQ) {
 459                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 460                 writel(isr, &hpet->hpet_isr);
 461         }
 462         writeq(g, &timer->hpet_config);
 463         local_irq_restore(flags);
 464
 465         return 0;
 466 }
 467
 468 /* converts Hz to number of timer ticks */
 469 static inline unsigned long hpet_time_div(struct hpets *hpets,
 470                                           unsigned long dis)
 471 {
 472         unsigned long long m;
 473
 474         m = hpets->hp_tick_freq + (dis >> 1);
 475         do_div(m, dis);
 476         return (unsigned long)m;
 477 }
 478
 479 static int
 480 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
 481 {
 482         struct hpet_timer __iomem *timer;
 483         struct hpet __iomem *hpet;
 484         struct hpets *hpetp;
 485         int err;
 486         unsigned long v;
 487
 488         switch (cmd) {
 489         case HPET_IE_OFF:
 490         case HPET_INFO:
 491         case HPET_EPI:
 492         case HPET_DPI:
 493         case HPET_IRQFREQ:
 494                 timer = devp->hd_timer;
 495                 hpet = devp->hd_hpet;
 496                 hpetp = devp->hd_hpets;
 497                 break;
 498         case HPET_IE_ON:
 499                 return hpet_ioctl_ieon(devp);
 500         default:
 501                 return -EINVAL;
 502         }
 503
 504         err = 0;
 505
 506         switch (cmd) {
 507         case HPET_IE_OFF:
 508                 if ((devp->hd_flags & HPET_IE) == 0)
 509                         break;
 510                 v = readq(&timer->hpet_config);
 511                 v &= ~Tn_INT_ENB_CNF_MASK;
 512                 writeq(v, &timer->hpet_config);
 513                 if (devp->hd_irq) {
 514                         free_irq(devp->hd_irq, devp);
 515                         devp->hd_irq = 0;
 516                 }
 517                 devp->hd_flags ^= HPET_IE;
 518                 break;
 519         case HPET_INFO:
 520                 {
 521                         struct hpet_info info;
 522
 523                         if (devp->hd_ireqfreq)
 524                                 info.hi_ireqfreq =
 525                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 526                         else
 527                                 info.hi_ireqfreq = 0;
 528                         info.hi_flags =
 529                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 530                         info.hi_hpet = hpetp->hp_which;
 531                         info.hi_timer = devp - hpetp->hp_dev;
 532                         if (kernel)
 533                                 memcpy((void *)arg, &info, sizeof(info));
 534                         else
 535                                 if (copy_to_user((void __user *)arg, &info,
 536                                                  sizeof(info)))
 537                                         err = -EFAULT;
 538                         break;
 539                 }
 540         case HPET_EPI:
 541                 v = readq(&timer->hpet_config);
 542                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 543                         err = -ENXIO;
 544                         break;
 545                 }
 546                 devp->hd_flags |= HPET_PERIODIC;
 547                 break;
 548         case HPET_DPI:
 549                 v = readq(&timer->hpet_config);
 550                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 551                         err = -ENXIO;
 552                         break;
 553                 }
 554                 if (devp->hd_flags & HPET_PERIODIC &&
 555                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 556                         v = readq(&timer->hpet_config);
 557                         v ^= Tn_TYPE_CNF_MASK;
 558                         writeq(v, &timer->hpet_config);
 559                 }
 560                 devp->hd_flags &= ~HPET_PERIODIC;
 561                 break;
 562         case HPET_IRQFREQ:
 563                 if (!kernel && (arg > hpet_max_freq) &&
 564                     !capable(CAP_SYS_RESOURCE)) {
 565                         err = -EACCES;
 566                         break;
 567                 }
 568
 569                 if (!arg) {
 570                         err = -EINVAL;
 571                         break;
 572                 }
 573
 574                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 575         }
 576
 577         return err;
 578 }
 579
 580 static const struct file_operations hpet_fops = {
 581         .owner = THIS_MODULE,
 582         .llseek = no_llseek,
 583         .read = hpet_read,
 584         .poll = hpet_poll,
 585         .ioctl = hpet_ioctl,
 586         .open = hpet_open,
 587         .release = hpet_release,
 588         .fasync = hpet_fasync,
 589         .mmap = hpet_mmap,
 590 };
 591
 592 static int hpet_is_known(struct hpet_data *hdp)
 593 {
 594         struct hpets *hpetp;
 595
 596         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 597                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 598                         return 1;
 599
 600         return 0;
 601 }
 602
 603 static inline int hpet_tpcheck(struct hpet_task *tp)
 604 {
 605         struct hpet_dev *devp;
 606         struct hpets *hpetp;
 607
 608         devp = tp->ht_opaque;
 609
 610         if (!devp)
 611                 return -ENXIO;
 612
 613         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 614                 if (devp >= hpetp->hp_dev
 615                     && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
 616                     && devp->hd_hpet == hpetp->hp_hpet)
 617                         return 0;
 618
 619         return -ENXIO;
 620 }
 621
 622 int hpet_unregister(struct hpet_task *tp)
 623 {
 624         struct hpet_dev *devp;
 625         struct hpet_timer __iomem *timer;
 626         int err;
 627
 628         if ((err = hpet_tpcheck(tp)))
 629                 return err;
 630
 631         spin_lock_irq(&hpet_task_lock);
 632         spin_lock(&hpet_lock);
 633
 634         devp = tp->ht_opaque;
 635         if (devp->hd_task != tp) {
 636                 spin_unlock(&hpet_lock);
 637                 spin_unlock_irq(&hpet_task_lock);
 638                 return -ENXIO;
 639         }
 640
 641         timer = devp->hd_timer;
 642         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 643                &timer->hpet_config);
 644         devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
 645         devp->hd_task = NULL;
 646         spin_unlock(&hpet_lock);
 647         spin_unlock_irq(&hpet_task_lock);
 648
 649         return 0;
 650 }
 651
 652 static ctl_table hpet_table[] = {
 653         {
 654          .ctl_name = CTL_UNNUMBERED,
 655          .procname = "max-user-freq",
 656          .data = &hpet_max_freq,
 657          .maxlen = sizeof(int),
 658          .mode = 0644,
 659          .proc_handler = &proc_dointvec,
 660          },
 661         {.ctl_name = 0}
 662 };
 663
 664 static ctl_table hpet_root[] = {
 665         {
 666          .ctl_name = CTL_UNNUMBERED,
 667          .procname = "hpet",
 668          .maxlen = 0,
 669          .mode = 0555,
 670          .child = hpet_table,
 671          },
 672         {.ctl_name = 0}
 673 };
 674
 675 static ctl_table dev_root[] = {
 676         {
 677          .ctl_name = CTL_DEV,
 678          .procname = "dev",
 679          .maxlen = 0,
 680          .mode = 0555,
 681          .child = hpet_root,
 682          },
 683         {.ctl_name = 0}
 684 };
 685
 686 static struct ctl_table_header *sysctl_header;
 687
 688 /*
 689  * Adjustment for when arming the timer with
 690  * initial conditions.  That is, main counter
 691  * ticks expired before interrupts are enabled.
 692  */
 693 #define TICK_CALIBRATE  (1000UL)
 694
 695 static unsigned long hpet_calibrate(struct hpets *hpetp)
 696 {
 697         struct hpet_timer __iomem *timer = NULL;
 698         unsigned long t, m, count, i, flags, start;
 699         struct hpet_dev *devp;
 700         int j;
 701         struct hpet __iomem *hpet;
 702
 703         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 704                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 705                         timer = devp->hd_timer;
 706                         break;
 707                 }
 708
 709         if (!timer)
 710                 return 0;
 711
 712         hpet = hpetp->hp_hpet;
 713         t = read_counter(&timer->hpet_compare);
 714
 715         i = 0;
 716         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 717
 718         local_irq_save(flags);
 719
 720         start = read_counter(&hpet->hpet_mc);
 721
 722         do {
 723                 m = read_counter(&hpet->hpet_mc);
 724                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 725         } while (i++, (m - start) < count);
 726
 727         local_irq_restore(flags);
 728
 729         return (m - start) / i;
 730 }
 731
 732 int hpet_alloc(struct hpet_data *hdp)
 733 {
 734         u64 cap, mcfg;
 735         struct hpet_dev *devp;
 736         u32 i, ntimer;
 737         struct hpets *hpetp;
 738         size_t siz;
 739         struct hpet __iomem *hpet;
 740         static struct hpets *last = NULL;
 741         unsigned long period;
 742         unsigned long long temp;
 743
 744         /*
 745          * hpet_alloc can be called by platform dependent code.
 746          * If platform dependent code has allocated the hpet that
 747          * ACPI has also reported, then we catch it here.
 748          */
 749         if (hpet_is_known(hdp)) {
 750                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 751                         __FUNCTION__);
 752                 return 0;
 753         }
 754
 755         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 756                                       sizeof(struct hpet_dev));
 757
 758         hpetp = kzalloc(siz, GFP_KERNEL);
 759
 760         if (!hpetp)
 761                 return -ENOMEM;
 762
 763         hpetp->hp_which = hpet_nhpet++;
 764         hpetp->hp_hpet = hdp->hd_address;
 765         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 766
 767         hpetp->hp_ntimer = hdp->hd_nirqs;
 768
 769         for (i = 0; i < hdp->hd_nirqs; i++)
 770                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 771
 772         hpet = hpetp->hp_hpet;
 773
 774         cap = readq(&hpet->hpet_cap);
 775
 776         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 777
 778         if (hpetp->hp_ntimer != ntimer) {
 779                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 780                        " with number of timers\n");
 781                 kfree(hpetp);
 782                 return -ENODEV;
 783         }
 784
 785         if (last)
 786                 last->hp_next = hpetp;
 787         else
 788                 hpets = hpetp;
 789
 790         last = hpetp;
 791
 792         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 793                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 794         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 795         temp += period >> 1; /* round */
 796         do_div(temp, period);
 797         hpetp->hp_tick_freq = temp; /* ticks per second */
 798
 799         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 800                 hpetp->hp_which, hdp->hd_phys_address,
 801                 hpetp->hp_ntimer > 1 ? "s" : "");
 802         for (i = 0; i < hpetp->hp_ntimer; i++)
 803                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 804         printk("\n");
 805
 806         printk(KERN_INFO "hpet%u: %u %d-bit timers, %Lu Hz\n",
 807                hpetp->hp_which, hpetp->hp_ntimer,
 808                cap & HPET_COUNTER_SIZE_MASK ? 64 : 32, hpetp->hp_tick_freq);
 809
 810         mcfg = readq(&hpet->hpet_config);
 811         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 812                 write_counter(0L, &hpet->hpet_mc);
 813                 mcfg |= HPET_ENABLE_CNF_MASK;
 814                 writeq(mcfg, &hpet->hpet_config);
 815         }
 816
 817         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 818                 struct hpet_timer __iomem *timer;
 819
 820                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 821
 822                 devp->hd_hpets = hpetp;
 823                 devp->hd_hpet = hpet;
 824                 devp->hd_timer = timer;
 825
 826                 /*
 827                  * If the timer was reserved by platform code,
 828                  * then make timer unavailable for opens.
 829                  */
 830                 if (hdp->hd_state & (1 << i)) {
 831                         devp->hd_flags = HPET_OPEN;
 832                         continue;
 833                 }
 834
 835                 init_waitqueue_head(&devp->hd_waitqueue);
 836         }
 837
 838         hpetp->hp_delta = hpet_calibrate(hpetp);
 839
 840 /* This clocksource driver currently only works on ia64 */
 841 #ifdef CONFIG_IA64
 842         if (!hpet_clocksource) {
 843                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 844                 CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
 845                 clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
 846                                                 clocksource_hpet.shift);
 847                 clocksource_register(&clocksource_hpet);
 848                 hpetp->hp_clocksource = &clocksource_hpet;
 849                 hpet_clocksource = &clocksource_hpet;
 850         }
 851 #endif
 852
 853         return 0;
 854 }
 855
 856 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 857 {
 858         struct hpet_data *hdp;
 859         acpi_status status;
 860         struct acpi_resource_address64 addr;
 861
 862         hdp = data;
 863
 864         status = acpi_resource_to_address64(res, &addr);
 865
 866         if (ACPI_SUCCESS(status)) {
 867                 hdp->hd_phys_address = addr.minimum;
 868                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 869
 870                 if (hpet_is_known(hdp)) {
 871                         printk(KERN_DEBUG "%s: 0x%lx is busy\n",
 872                                 __FUNCTION__, hdp->hd_phys_address);
 873                         iounmap(hdp->hd_address);
 874                         return AE_ALREADY_EXISTS;
 875                 }
 876         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 877                 struct acpi_resource_fixed_memory32 *fixmem32;
 878
 879                 fixmem32 = &res->data.fixed_memory32;
 880                 if (!fixmem32)
 881                         return AE_NO_MEMORY;
 882
 883                 hdp->hd_phys_address = fixmem32->address;
 884                 hdp->hd_address = ioremap(fixmem32->address,
 885                                                 HPET_RANGE_SIZE);
 886
 887                 if (hpet_is_known(hdp)) {
 888                         printk(KERN_DEBUG "%s: 0x%lx is busy\n",
 889                                 __FUNCTION__, hdp->hd_phys_address);
 890                         iounmap(hdp->hd_address);
 891                         return AE_ALREADY_EXISTS;
 892                 }
 893         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 894                 struct acpi_resource_extended_irq *irqp;
 895                 int i, irq;
 896
 897                 irqp = &res->data.extended_irq;
 898
 899                 for (i = 0; i < irqp->interrupt_count; i++) {
 900                         irq = acpi_register_gsi(irqp->interrupts[i],
 901                                       irqp->triggering, irqp->polarity);
 902                         if (irq < 0)
 903                                 return AE_ERROR;
 904
 905                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 906                         hdp->hd_nirqs++;
 907                 }
 908         }
 909
 910         return AE_OK;
 911 }
 912
 913 static int hpet_acpi_add(struct acpi_device *device)
 914 {
 915         acpi_status result;
 916         struct hpet_data data;
 917
 918         memset(&data, 0, sizeof(data));
 919
 920         result =
 921             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 922                                 hpet_resources, &data);
 923
 924         if (ACPI_FAILURE(result))
 925                 return -ENODEV;
 926
 927         if (!data.hd_address || !data.hd_nirqs) {
 928                 printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
 929                 return -ENODEV;
 930         }
 931
 932         return hpet_alloc(&data);
 933 }
 934
 935 static int hpet_acpi_remove(struct acpi_device *device, int type)
 936 {
 937         /* XXX need to unregister clocksource, dealloc mem, etc */
 938         return -EINVAL;
 939 }
 940
 941 static const struct acpi_device_id hpet_device_ids[] = {
 942         {"PNP0103", 0},
 943         {"", 0},
 944 };
 945 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
 946
 947 static struct acpi_driver hpet_acpi_driver = {
 948         .name = "hpet",
 949         .ids = hpet_device_ids,
 950         .ops = {
 951                 .add = hpet_acpi_add,
 952                 .remove = hpet_acpi_remove,
 953                 },
 954 };
 955
 956 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
 957
 958 static int __init hpet_init(void)
 959 {
 960         int result;
 961
 962         result = misc_register(&hpet_misc);
 963         if (result < 0)
 964                 return -ENODEV;
 965
 966         sysctl_header = register_sysctl_table(dev_root);
 967
 968         result = acpi_bus_register_driver(&hpet_acpi_driver);
 969         if (result < 0) {
 970                 if (sysctl_header)
 971                         unregister_sysctl_table(sysctl_header);
 972                 misc_deregister(&hpet_misc);
 973                 return result;
 974         }
 975
 976         return 0;
 977 }
 978
 979 static void __exit hpet_exit(void)
 980 {
 981         acpi_bus_unregister_driver(&hpet_acpi_driver);
 982
 983         if (sysctl_header)
 984                 unregister_sysctl_table(sysctl_header);
 985         misc_deregister(&hpet_misc);
 986
 987         return;
 988 }
 989
 990 module_init(hpet_init);
 991 module_exit(hpet_exit);
 992 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
 993 MODULE_LICENSE("GPL");