drivers/char/hpet.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Intel & MS High Precision Event Timer Implementation.
   4  *
   5  * Copyright (C) 2003 Intel Corporation
   6  *      Venki Pallipadi
   7  * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
   8  *      Bob Picco <robert.picco@hp.com>
   9  */
  10
  11 #include <linux/interrupt.h>
  12 #include <linux/kernel.h>
  13 #include <linux/types.h>
  14 #include <linux/miscdevice.h>
  15 #include <linux/major.h>
  16 #include <linux/ioport.h>
  17 #include <linux/fcntl.h>
  18 #include <linux/init.h>
  19 #include <linux/io-64-nonatomic-lo-hi.h>
  20 #include <linux/poll.h>
  21 #include <linux/mm.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/sysctl.h>
  25 #include <linux/wait.h>
  26 #include <linux/sched/signal.h>
  27 #include <linux/bcd.h>
  28 #include <linux/seq_file.h>
  29 #include <linux/bitops.h>
  30 #include <linux/compat.h>
  31 #include <linux/clocksource.h>
  32 #include <linux/uaccess.h>
  33 #include <linux/slab.h>
  34 #include <linux/io.h>
  35 #include <linux/acpi.h>
  36 #include <linux/hpet.h>
  37 #include <asm/current.h>
  38 #include <asm/irq.h>
  39 #include <asm/div64.h>
  40
  41 /*
  42  * The High Precision Event Timer driver.
  43  * This driver is closely modelled after the rtc.c driver.
  44  * See HPET spec revision 1.
  45  */
  46 #define HPET_USER_FREQ  (64)
  47 #define HPET_DRIFT      (500)
  48
  49 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
  50
  51
  52 /* WARNING -- don't get confused.  These macros are never used
  53  * to write the (single) counter, and rarely to read it.
  54  * They're badly named; to fix, someday.
  55  */
  56 #if BITS_PER_LONG == 64
  57 #define write_counter(V, MC)    writeq(V, MC)
  58 #define read_counter(MC)        readq(MC)
  59 #else
  60 #define write_counter(V, MC)    writel(V, MC)
  61 #define read_counter(MC)        readl(MC)
  62 #endif
  63
  64 static DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
  65 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  66
  67 /* A lock for concurrent access by app and isr hpet activity. */
  68 static DEFINE_SPINLOCK(hpet_lock);
  69
  70 #define HPET_DEV_NAME   (7)
  71
  72 struct hpet_dev {
  73         struct hpets *hd_hpets;
  74         struct hpet __iomem *hd_hpet;
  75         struct hpet_timer __iomem *hd_timer;
  76         unsigned long hd_ireqfreq;
  77         unsigned long hd_irqdata;
  78         wait_queue_head_t hd_waitqueue;
  79         struct fasync_struct *hd_async_queue;
  80         unsigned int hd_flags;
  81         unsigned int hd_irq;
  82         unsigned int hd_hdwirq;
  83         char hd_name[HPET_DEV_NAME];
  84 };
  85
  86 struct hpets {
  87         struct hpets *hp_next;
  88         struct hpet __iomem *hp_hpet;
  89         unsigned long hp_hpet_phys;
  90         struct clocksource *hp_clocksource;
  91         unsigned long long hp_tick_freq;
  92         unsigned long hp_delta;
  93         unsigned int hp_ntimer;
  94         unsigned int hp_which;
  95         struct hpet_dev hp_dev[] __counted_by(hp_ntimer);
  96 };
  97
  98 static struct hpets *hpets;
  99
 100 #define HPET_OPEN               0x0001
 101 #define HPET_IE                 0x0002  /* interrupt enabled */
 102 #define HPET_PERIODIC           0x0004
 103 #define HPET_SHARED_IRQ         0x0008
 104
 105 static irqreturn_t hpet_interrupt(int irq, void *data)
 106 {
 107         struct hpet_dev *devp;
 108         unsigned long isr;
 109
 110         devp = data;
 111         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 112
 113         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 114             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 115                 return IRQ_NONE;
 116
 117         spin_lock(&hpet_lock);
 118         devp->hd_irqdata++;
 119
 120         /*
 121          * For non-periodic timers, increment the accumulator.
 122          * This has the effect of treating non-periodic like periodic.
 123          */
 124         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 125                 unsigned long t, mc, base, k;
 126                 struct hpet __iomem *hpet = devp->hd_hpet;
 127                 struct hpets *hpetp = devp->hd_hpets;
 128
 129                 t = devp->hd_ireqfreq;
 130                 read_counter(&devp->hd_timer->hpet_compare);
 131                 mc = read_counter(&hpet->hpet_mc);
 132                 /* The time for the next interrupt would logically be t + m,
 133                  * however, if we are very unlucky and the interrupt is delayed
 134                  * for longer than t then we will completely miss the next
 135                  * interrupt if we set t + m and an application will hang.
 136                  * Therefore we need to make a more complex computation assuming
 137                  * that there exists a k for which the following is true:
 138                  * k * t + base < mc + delta
 139                  * (k + 1) * t + base > mc + delta
 140                  * where t is the interval in hpet ticks for the given freq,
 141                  * base is the theoretical start value 0 < base < t,
 142                  * mc is the main counter value at the time of the interrupt,
 143                  * delta is the time it takes to write the a value to the
 144                  * comparator.
 145                  * k may then be computed as (mc - base + delta) / t .
 146                  */
 147                 base = mc % t;
 148                 k = (mc - base + hpetp->hp_delta) / t;
 149                 write_counter(t * (k + 1) + base,
 150                               &devp->hd_timer->hpet_compare);
 151         }
 152
 153         if (devp->hd_flags & HPET_SHARED_IRQ)
 154                 writel(isr, &devp->hd_hpet->hpet_isr);
 155         spin_unlock(&hpet_lock);
 156
 157         wake_up_interruptible(&devp->hd_waitqueue);
 158
 159         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 160
 161         return IRQ_HANDLED;
 162 }
 163
 164 static void hpet_timer_set_irq(struct hpet_dev *devp)
 165 {
 166         unsigned long v;
 167         int irq, gsi;
 168         struct hpet_timer __iomem *timer;
 169
 170         spin_lock_irq(&hpet_lock);
 171         if (devp->hd_hdwirq) {
 172                 spin_unlock_irq(&hpet_lock);
 173                 return;
 174         }
 175
 176         timer = devp->hd_timer;
 177
 178         /* we prefer level triggered mode */
 179         v = readl(&timer->hpet_config);
 180         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
 181                 v |= Tn_INT_TYPE_CNF_MASK;
 182                 writel(v, &timer->hpet_config);
 183         }
 184         spin_unlock_irq(&hpet_lock);
 185
 186         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
 187                                  Tn_INT_ROUTE_CAP_SHIFT;
 188
 189         /*
 190          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
 191          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
 192          */
 193         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 194                 v &= ~0xf3df;
 195         else
 196                 v &= ~0xffff;
 197
 198         for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
 199                 if (irq >= nr_irqs) {
 200                         irq = HPET_MAX_IRQ;
 201                         break;
 202                 }
 203
 204                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
 205                                         ACPI_ACTIVE_LOW);
 206                 if (gsi > 0)
 207                         break;
 208
 209                 /* FIXME: Setup interrupt source table */
 210         }
 211
 212         if (irq < HPET_MAX_IRQ) {
 213                 spin_lock_irq(&hpet_lock);
 214                 v = readl(&timer->hpet_config);
 215                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 216                 writel(v, &timer->hpet_config);
 217                 devp->hd_hdwirq = gsi;
 218                 spin_unlock_irq(&hpet_lock);
 219         }
 220         return;
 221 }
 222
 223 static int hpet_open(struct inode *inode, struct file *file)
 224 {
 225         struct hpet_dev *devp;
 226         struct hpets *hpetp;
 227         int i;
 228
 229         if (file->f_mode & FMODE_WRITE)
 230                 return -EINVAL;
 231
 232         mutex_lock(&hpet_mutex);
 233         spin_lock_irq(&hpet_lock);
 234
 235         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 236                 for (i = 0; i < hpetp->hp_ntimer; i++)
 237                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN) {
 238                                 continue;
 239                         } else {
 240                                 devp = &hpetp->hp_dev[i];
 241                                 break;
 242                         }
 243
 244         if (!devp) {
 245                 spin_unlock_irq(&hpet_lock);
 246                 mutex_unlock(&hpet_mutex);
 247                 return -EBUSY;
 248         }
 249
 250         file->private_data = devp;
 251         devp->hd_irqdata = 0;
 252         devp->hd_flags |= HPET_OPEN;
 253         spin_unlock_irq(&hpet_lock);
 254         mutex_unlock(&hpet_mutex);
 255
 256         hpet_timer_set_irq(devp);
 257
 258         return 0;
 259 }
 260
 261 static ssize_t
 262 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 263 {
 264         DECLARE_WAITQUEUE(wait, current);
 265         unsigned long data;
 266         ssize_t retval;
 267         struct hpet_dev *devp;
 268
 269         devp = file->private_data;
 270         if (!devp->hd_ireqfreq)
 271                 return -EIO;
 272
 273         if (count < sizeof(unsigned long))
 274                 return -EINVAL;
 275
 276         add_wait_queue(&devp->hd_waitqueue, &wait);
 277
 278         for ( ; ; ) {
 279                 set_current_state(TASK_INTERRUPTIBLE);
 280
 281                 spin_lock_irq(&hpet_lock);
 282                 data = devp->hd_irqdata;
 283                 devp->hd_irqdata = 0;
 284                 spin_unlock_irq(&hpet_lock);
 285
 286                 if (data) {
 287                         break;
 288                 } else if (file->f_flags & O_NONBLOCK) {
 289                         retval = -EAGAIN;
 290                         goto out;
 291                 } else if (signal_pending(current)) {
 292                         retval = -ERESTARTSYS;
 293                         goto out;
 294                 }
 295                 schedule();
 296         }
 297
 298         retval = put_user(data, (unsigned long __user *)buf);
 299         if (!retval)
 300                 retval = sizeof(unsigned long);
 301 out:
 302         __set_current_state(TASK_RUNNING);
 303         remove_wait_queue(&devp->hd_waitqueue, &wait);
 304
 305         return retval;
 306 }
 307
 308 static __poll_t hpet_poll(struct file *file, poll_table * wait)
 309 {
 310         unsigned long v;
 311         struct hpet_dev *devp;
 312
 313         devp = file->private_data;
 314
 315         if (!devp->hd_ireqfreq)
 316                 return 0;
 317
 318         poll_wait(file, &devp->hd_waitqueue, wait);
 319
 320         spin_lock_irq(&hpet_lock);
 321         v = devp->hd_irqdata;
 322         spin_unlock_irq(&hpet_lock);
 323
 324         if (v != 0)
 325                 return EPOLLIN | EPOLLRDNORM;
 326
 327         return 0;
 328 }
 329
 330 #ifdef CONFIG_HPET_MMAP
 331 #ifdef CONFIG_HPET_MMAP_DEFAULT
 332 static int hpet_mmap_enabled = 1;
 333 #else
 334 static int hpet_mmap_enabled = 0;
 335 #endif
 336
 337 static __init int hpet_mmap_enable(char *str)
 338 {
 339         get_option(&str, &hpet_mmap_enabled);
 340         pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
 341         return 1;
 342 }
 343 __setup("hpet_mmap=", hpet_mmap_enable);
 344
 345 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 346 {
 347         struct hpet_dev *devp;
 348         unsigned long addr;
 349
 350         if (!hpet_mmap_enabled)
 351                 return -EACCES;
 352
 353         devp = file->private_data;
 354         addr = devp->hd_hpets->hp_hpet_phys;
 355
 356         if (addr & (PAGE_SIZE - 1))
 357                 return -ENOSYS;
 358
 359         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 360         return vm_iomap_memory(vma, addr, PAGE_SIZE);
 361 }
 362 #else
 363 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 364 {
 365         return -ENOSYS;
 366 }
 367 #endif
 368
 369 static int hpet_fasync(int fd, struct file *file, int on)
 370 {
 371         struct hpet_dev *devp;
 372
 373         devp = file->private_data;
 374
 375         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 376                 return 0;
 377         else
 378                 return -EIO;
 379 }
 380
 381 static int hpet_release(struct inode *inode, struct file *file)
 382 {
 383         struct hpet_dev *devp;
 384         struct hpet_timer __iomem *timer;
 385         int irq = 0;
 386
 387         devp = file->private_data;
 388         timer = devp->hd_timer;
 389
 390         spin_lock_irq(&hpet_lock);
 391
 392         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 393                &timer->hpet_config);
 394
 395         irq = devp->hd_irq;
 396         devp->hd_irq = 0;
 397
 398         devp->hd_ireqfreq = 0;
 399
 400         if (devp->hd_flags & HPET_PERIODIC
 401             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 402                 unsigned long v;
 403
 404                 v = readq(&timer->hpet_config);
 405                 v ^= Tn_TYPE_CNF_MASK;
 406                 writeq(v, &timer->hpet_config);
 407         }
 408
 409         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 410         spin_unlock_irq(&hpet_lock);
 411
 412         if (irq)
 413                 free_irq(irq, devp);
 414
 415         file->private_data = NULL;
 416         return 0;
 417 }
 418
 419 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 420 {
 421         struct hpet_timer __iomem *timer;
 422         struct hpet __iomem *hpet;
 423         struct hpets *hpetp;
 424         int irq;
 425         unsigned long g, v, t, m;
 426         unsigned long flags, isr;
 427
 428         timer = devp->hd_timer;
 429         hpet = devp->hd_hpet;
 430         hpetp = devp->hd_hpets;
 431
 432         if (!devp->hd_ireqfreq)
 433                 return -EIO;
 434
 435         spin_lock_irq(&hpet_lock);
 436
 437         if (devp->hd_flags & HPET_IE) {
 438                 spin_unlock_irq(&hpet_lock);
 439                 return -EBUSY;
 440         }
 441
 442         devp->hd_flags |= HPET_IE;
 443
 444         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 445                 devp->hd_flags |= HPET_SHARED_IRQ;
 446         spin_unlock_irq(&hpet_lock);
 447
 448         irq = devp->hd_hdwirq;
 449
 450         if (irq) {
 451                 unsigned long irq_flags;
 452
 453                 if (devp->hd_flags & HPET_SHARED_IRQ) {
 454                         /*
 455                          * To prevent the interrupt handler from seeing an
 456                          * unwanted interrupt status bit, program the timer
 457                          * so that it will not fire in the near future ...
 458                          */
 459                         writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
 460                                &timer->hpet_config);
 461                         write_counter(read_counter(&hpet->hpet_mc),
 462                                       &timer->hpet_compare);
 463                         /* ... and clear any left-over status. */
 464                         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 465                         writel(isr, &hpet->hpet_isr);
 466                 }
 467
 468                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 469                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
 470                 if (request_irq(irq, hpet_interrupt, irq_flags,
 471                                 devp->hd_name, (void *)devp)) {
 472                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 473                         irq = 0;
 474                 }
 475         }
 476
 477         if (irq == 0) {
 478                 spin_lock_irq(&hpet_lock);
 479                 devp->hd_flags ^= HPET_IE;
 480                 spin_unlock_irq(&hpet_lock);
 481                 return -EIO;
 482         }
 483
 484         devp->hd_irq = irq;
 485         t = devp->hd_ireqfreq;
 486         v = readq(&timer->hpet_config);
 487
 488         /* 64-bit comparators are not yet supported through the ioctls,
 489          * so force this into 32-bit mode if it supports both modes
 490          */
 491         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 492
 493         if (devp->hd_flags & HPET_PERIODIC) {
 494                 g |= Tn_TYPE_CNF_MASK;
 495                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 496                 writeq(v, &timer->hpet_config);
 497                 local_irq_save(flags);
 498
 499                 /*
 500                  * NOTE: First we modify the hidden accumulator
 501                  * register supported by periodic-capable comparators.
 502                  * We never want to modify the (single) counter; that
 503                  * would affect all the comparators. The value written
 504                  * is the counter value when the first interrupt is due.
 505                  */
 506                 m = read_counter(&hpet->hpet_mc);
 507                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 508                 /*
 509                  * Then we modify the comparator, indicating the period
 510                  * for subsequent interrupt.
 511                  */
 512                 write_counter(t, &timer->hpet_compare);
 513         } else {
 514                 local_irq_save(flags);
 515                 m = read_counter(&hpet->hpet_mc);
 516                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 517         }
 518
 519         if (devp->hd_flags & HPET_SHARED_IRQ) {
 520                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 521                 writel(isr, &hpet->hpet_isr);
 522         }
 523         writeq(g, &timer->hpet_config);
 524         local_irq_restore(flags);
 525
 526         return 0;
 527 }
 528
 529 /* converts Hz to number of timer ticks */
 530 static inline unsigned long hpet_time_div(struct hpets *hpets,
 531                                           unsigned long dis)
 532 {
 533         unsigned long long m;
 534
 535         m = hpets->hp_tick_freq + (dis >> 1);
 536         return div64_ul(m, dis);
 537 }
 538
 539 static int
 540 hpet_ioctl_common(struct hpet_dev *devp, unsigned int cmd, unsigned long arg,
 541                   struct hpet_info *info)
 542 {
 543         struct hpet_timer __iomem *timer;
 544         struct hpets *hpetp;
 545         int err;
 546         unsigned long v;
 547
 548         switch (cmd) {
 549         case HPET_IE_OFF:
 550         case HPET_INFO:
 551         case HPET_EPI:
 552         case HPET_DPI:
 553         case HPET_IRQFREQ:
 554                 timer = devp->hd_timer;
 555                 hpetp = devp->hd_hpets;
 556                 break;
 557         case HPET_IE_ON:
 558                 return hpet_ioctl_ieon(devp);
 559         default:
 560                 return -EINVAL;
 561         }
 562
 563         err = 0;
 564
 565         switch (cmd) {
 566         case HPET_IE_OFF:
 567                 if ((devp->hd_flags & HPET_IE) == 0)
 568                         break;
 569                 v = readq(&timer->hpet_config);
 570                 v &= ~Tn_INT_ENB_CNF_MASK;
 571                 writeq(v, &timer->hpet_config);
 572                 if (devp->hd_irq) {
 573                         free_irq(devp->hd_irq, devp);
 574                         devp->hd_irq = 0;
 575                 }
 576                 devp->hd_flags ^= HPET_IE;
 577                 break;
 578         case HPET_INFO:
 579                 {
 580                         memset(info, 0, sizeof(*info));
 581                         if (devp->hd_ireqfreq)
 582                                 info->hi_ireqfreq =
 583                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 584                         info->hi_flags =
 585                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 586                         info->hi_hpet = hpetp->hp_which;
 587                         info->hi_timer = devp - hpetp->hp_dev;
 588                         break;
 589                 }
 590         case HPET_EPI:
 591                 v = readq(&timer->hpet_config);
 592                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 593                         err = -ENXIO;
 594                         break;
 595                 }
 596                 devp->hd_flags |= HPET_PERIODIC;
 597                 break;
 598         case HPET_DPI:
 599                 v = readq(&timer->hpet_config);
 600                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 601                         err = -ENXIO;
 602                         break;
 603                 }
 604                 if (devp->hd_flags & HPET_PERIODIC &&
 605                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 606                         v = readq(&timer->hpet_config);
 607                         v ^= Tn_TYPE_CNF_MASK;
 608                         writeq(v, &timer->hpet_config);
 609                 }
 610                 devp->hd_flags &= ~HPET_PERIODIC;
 611                 break;
 612         case HPET_IRQFREQ:
 613                 if ((arg > hpet_max_freq) &&
 614                     !capable(CAP_SYS_RESOURCE)) {
 615                         err = -EACCES;
 616                         break;
 617                 }
 618
 619                 if (!arg) {
 620                         err = -EINVAL;
 621                         break;
 622                 }
 623
 624                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 625         }
 626
 627         return err;
 628 }
 629
 630 static long
 631 hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 632 {
 633         struct hpet_info info;
 634         int err;
 635
 636         mutex_lock(&hpet_mutex);
 637         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 638         mutex_unlock(&hpet_mutex);
 639
 640         if ((cmd == HPET_INFO) && !err &&
 641             (copy_to_user((void __user *)arg, &info, sizeof(info))))
 642                 err = -EFAULT;
 643
 644         return err;
 645 }
 646
 647 #ifdef CONFIG_COMPAT
 648 struct compat_hpet_info {
 649         compat_ulong_t hi_ireqfreq;     /* Hz */
 650         compat_ulong_t hi_flags;        /* information */
 651         unsigned short hi_hpet;
 652         unsigned short hi_timer;
 653 };
 654
 655 static long
 656 hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 657 {
 658         struct hpet_info info;
 659         int err;
 660
 661         mutex_lock(&hpet_mutex);
 662         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 663         mutex_unlock(&hpet_mutex);
 664
 665         if ((cmd == HPET_INFO) && !err) {
 666                 struct compat_hpet_info __user *u = compat_ptr(arg);
 667                 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
 668                     put_user(info.hi_flags, &u->hi_flags) ||
 669                     put_user(info.hi_hpet, &u->hi_hpet) ||
 670                     put_user(info.hi_timer, &u->hi_timer))
 671                         err = -EFAULT;
 672         }
 673
 674         return err;
 675 }
 676 #endif
 677
 678 static const struct file_operations hpet_fops = {
 679         .owner = THIS_MODULE,
 680         .llseek = no_llseek,
 681         .read = hpet_read,
 682         .poll = hpet_poll,
 683         .unlocked_ioctl = hpet_ioctl,
 684 #ifdef CONFIG_COMPAT
 685         .compat_ioctl = hpet_compat_ioctl,
 686 #endif
 687         .open = hpet_open,
 688         .release = hpet_release,
 689         .fasync = hpet_fasync,
 690         .mmap = hpet_mmap,
 691 };
 692
 693 static int hpet_is_known(struct hpet_data *hdp)
 694 {
 695         struct hpets *hpetp;
 696
 697         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 698                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 699                         return 1;
 700
 701         return 0;
 702 }
 703
 704 static struct ctl_table hpet_table[] = {
 705         {
 706          .procname = "max-user-freq",
 707          .data = &hpet_max_freq,
 708          .maxlen = sizeof(int),
 709          .mode = 0644,
 710          .proc_handler = proc_dointvec,
 711          },
 712 };
 713
 714 static struct ctl_table_header *sysctl_header;
 715
 716 /*
 717  * Adjustment for when arming the timer with
 718  * initial conditions.  That is, main counter
 719  * ticks expired before interrupts are enabled.
 720  */
 721 #define TICK_CALIBRATE  (1000UL)
 722
 723 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 724 {
 725         struct hpet_timer __iomem *timer = NULL;
 726         unsigned long t, m, count, i, flags, start;
 727         struct hpet_dev *devp;
 728         int j;
 729         struct hpet __iomem *hpet;
 730
 731         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 732                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 733                         timer = devp->hd_timer;
 734                         break;
 735                 }
 736
 737         if (!timer)
 738                 return 0;
 739
 740         hpet = hpetp->hp_hpet;
 741         t = read_counter(&timer->hpet_compare);
 742
 743         i = 0;
 744         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 745
 746         local_irq_save(flags);
 747
 748         start = read_counter(&hpet->hpet_mc);
 749
 750         do {
 751                 m = read_counter(&hpet->hpet_mc);
 752                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 753         } while (i++, (m - start) < count);
 754
 755         local_irq_restore(flags);
 756
 757         return (m - start) / i;
 758 }
 759
 760 static unsigned long hpet_calibrate(struct hpets *hpetp)
 761 {
 762         unsigned long ret = ~0UL;
 763         unsigned long tmp;
 764
 765         /*
 766          * Try to calibrate until return value becomes stable small value.
 767          * If SMI interruption occurs in calibration loop, the return value
 768          * will be big. This avoids its impact.
 769          */
 770         for ( ; ; ) {
 771                 tmp = __hpet_calibrate(hpetp);
 772                 if (ret <= tmp)
 773                         break;
 774                 ret = tmp;
 775         }
 776
 777         return ret;
 778 }
 779
 780 int hpet_alloc(struct hpet_data *hdp)
 781 {
 782         u64 cap, mcfg;
 783         struct hpet_dev *devp;
 784         u32 i, ntimer;
 785         struct hpets *hpetp;
 786         struct hpet __iomem *hpet;
 787         static struct hpets *last;
 788         unsigned long period;
 789         unsigned long long temp;
 790         u32 remainder;
 791
 792         /*
 793          * hpet_alloc can be called by platform dependent code.
 794          * If platform dependent code has allocated the hpet that
 795          * ACPI has also reported, then we catch it here.
 796          */
 797         if (hpet_is_known(hdp)) {
 798                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 799                         __func__);
 800                 return 0;
 801         }
 802
 803         hpetp = kzalloc(struct_size(hpetp, hp_dev, hdp->hd_nirqs),
 804                         GFP_KERNEL);
 805
 806         if (!hpetp)
 807                 return -ENOMEM;
 808
 809         hpetp->hp_which = hpet_nhpet++;
 810         hpetp->hp_hpet = hdp->hd_address;
 811         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 812
 813         hpetp->hp_ntimer = hdp->hd_nirqs;
 814
 815         for (i = 0; i < hdp->hd_nirqs; i++)
 816                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 817
 818         hpet = hpetp->hp_hpet;
 819
 820         cap = readq(&hpet->hpet_cap);
 821
 822         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 823
 824         if (hpetp->hp_ntimer != ntimer) {
 825                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 826                        " with number of timers\n");
 827                 kfree(hpetp);
 828                 return -ENODEV;
 829         }
 830
 831         if (last)
 832                 last->hp_next = hpetp;
 833         else
 834                 hpets = hpetp;
 835
 836         last = hpetp;
 837
 838         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 839                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 840         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 841         temp += period >> 1; /* round */
 842         do_div(temp, period);
 843         hpetp->hp_tick_freq = temp; /* ticks per second */
 844
 845         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 846                 hpetp->hp_which, hdp->hd_phys_address,
 847                 hpetp->hp_ntimer > 1 ? "s" : "");
 848         for (i = 0; i < hpetp->hp_ntimer; i++)
 849                 printk(KERN_CONT "%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 850         printk(KERN_CONT "\n");
 851
 852         temp = hpetp->hp_tick_freq;
 853         remainder = do_div(temp, 1000000);
 854         printk(KERN_INFO
 855                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 856                 hpetp->hp_which, hpetp->hp_ntimer,
 857                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 858                 (unsigned) temp, remainder);
 859
 860         mcfg = readq(&hpet->hpet_config);
 861         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 862                 write_counter(0L, &hpet->hpet_mc);
 863                 mcfg |= HPET_ENABLE_CNF_MASK;
 864                 writeq(mcfg, &hpet->hpet_config);
 865         }
 866
 867         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 868                 struct hpet_timer __iomem *timer;
 869
 870                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 871
 872                 devp->hd_hpets = hpetp;
 873                 devp->hd_hpet = hpet;
 874                 devp->hd_timer = timer;
 875
 876                 /*
 877                  * If the timer was reserved by platform code,
 878                  * then make timer unavailable for opens.
 879                  */
 880                 if (hdp->hd_state & (1 << i)) {
 881                         devp->hd_flags = HPET_OPEN;
 882                         continue;
 883                 }
 884
 885                 init_waitqueue_head(&devp->hd_waitqueue);
 886         }
 887
 888         hpetp->hp_delta = hpet_calibrate(hpetp);
 889
 890         return 0;
 891 }
 892
 893 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 894 {
 895         struct hpet_data *hdp;
 896         acpi_status status;
 897         struct acpi_resource_address64 addr;
 898
 899         hdp = data;
 900
 901         status = acpi_resource_to_address64(res, &addr);
 902
 903         if (ACPI_SUCCESS(status)) {
 904                 hdp->hd_phys_address = addr.address.minimum;
 905                 hdp->hd_address = ioremap(addr.address.minimum, addr.address.address_length);
 906                 if (!hdp->hd_address)
 907                         return AE_ERROR;
 908
 909                 if (hpet_is_known(hdp)) {
 910                         iounmap(hdp->hd_address);
 911                         return AE_ALREADY_EXISTS;
 912                 }
 913         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 914                 struct acpi_resource_fixed_memory32 *fixmem32;
 915
 916                 fixmem32 = &res->data.fixed_memory32;
 917
 918                 hdp->hd_phys_address = fixmem32->address;
 919                 hdp->hd_address = ioremap(fixmem32->address,
 920                                                 HPET_RANGE_SIZE);
 921                 if (!hdp->hd_address)
 922                         return AE_ERROR;
 923
 924                 if (hpet_is_known(hdp)) {
 925                         iounmap(hdp->hd_address);
 926                         return AE_ALREADY_EXISTS;
 927                 }
 928         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 929                 struct acpi_resource_extended_irq *irqp;
 930                 int i, irq;
 931
 932                 irqp = &res->data.extended_irq;
 933
 934                 for (i = 0; i < irqp->interrupt_count; i++) {
 935                         if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
 936                                 break;
 937
 938                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
 939                                                 irqp->triggering,
 940                                                 irqp->polarity);
 941                         if (irq < 0)
 942                                 return AE_ERROR;
 943
 944                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 945                         hdp->hd_nirqs++;
 946                 }
 947         }
 948
 949         return AE_OK;
 950 }
 951
 952 static int hpet_acpi_add(struct acpi_device *device)
 953 {
 954         acpi_status result;
 955         struct hpet_data data;
 956
 957         memset(&data, 0, sizeof(data));
 958
 959         result =
 960             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 961                                 hpet_resources, &data);
 962
 963         if (ACPI_FAILURE(result))
 964                 return -ENODEV;
 965
 966         if (!data.hd_address || !data.hd_nirqs) {
 967                 if (data.hd_address)
 968                         iounmap(data.hd_address);
 969                 printk("%s: no address or irqs in _CRS\n", __func__);
 970                 return -ENODEV;
 971         }
 972
 973         return hpet_alloc(&data);
 974 }
 975
 976 static const struct acpi_device_id hpet_device_ids[] = {
 977         {"PNP0103", 0},
 978         {"", 0},
 979 };
 980
 981 static struct acpi_driver hpet_acpi_driver = {
 982         .name = "hpet",
 983         .ids = hpet_device_ids,
 984         .ops = {
 985                 .add = hpet_acpi_add,
 986                 },
 987 };
 988
 989 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
 990
 991 static int __init hpet_init(void)
 992 {
 993         int result;
 994
 995         result = misc_register(&hpet_misc);
 996         if (result < 0)
 997                 return -ENODEV;
 998
 999         sysctl_header = register_sysctl("dev/hpet", hpet_table);
1000
1001         result = acpi_bus_register_driver(&hpet_acpi_driver);
1002         if (result < 0) {
1003                 if (sysctl_header)
1004                         unregister_sysctl_table(sysctl_header);
1005                 misc_deregister(&hpet_misc);
1006                 return result;
1007         }
1008
1009         return 0;
1010 }
1011 device_initcall(hpet_init);
1012
1013 /*
1014 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1015 MODULE_LICENSE("GPL");
1016 */