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/kernel.h>
  16 #include <linux/types.h>
  17 #include <linux/miscdevice.h>
  18 #include <linux/major.h>
  19 #include <linux/ioport.h>
  20 #include <linux/fcntl.h>
  21 #include <linux/init.h>
  22 #include <linux/poll.h>
  23 #include <linux/mm.h>
  24 #include <linux/proc_fs.h>
  25 #include <linux/spinlock.h>
  26 #include <linux/sysctl.h>
  27 #include <linux/wait.h>
  28 #include <linux/sched/signal.h>
  29 #include <linux/bcd.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/bitops.h>
  32 #include <linux/compat.h>
  33 #include <linux/clocksource.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/slab.h>
  36 #include <linux/io.h>
  37 #include <linux/acpi.h>
  38 #include <linux/hpet.h>
  39 #include <asm/current.h>
  40 #include <asm/irq.h>
  41 #include <asm/div64.h>
  42
  43 /*
  44  * The High Precision Event Timer driver.
  45  * This driver is closely modelled after the rtc.c driver.
  46  * See HPET spec revision 1.
  47  */
  48 #define HPET_USER_FREQ  (64)
  49 #define HPET_DRIFT      (500)
  50
  51 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
  52
  53
  54 /* WARNING -- don't get confused.  These macros are never used
  55  * to write the (single) counter, and rarely to read it.
  56  * They're badly named; to fix, someday.
  57  */
  58 #if BITS_PER_LONG == 64
  59 #define write_counter(V, MC)    writeq(V, MC)
  60 #define read_counter(MC)        readq(MC)
  61 #else
  62 #define write_counter(V, MC)    writel(V, MC)
  63 #define read_counter(MC)        readl(MC)
  64 #endif
  65
  66 static DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
  67 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  68
  69 /* This clocksource driver currently only works on ia64 */
  70 #ifdef CONFIG_IA64
  71 static void __iomem *hpet_mctr;
  72
  73 static u64 read_hpet(struct clocksource *cs)
  74 {
  75         return (u64)read_counter((void __iomem *)hpet_mctr);
  76 }
  77
  78 static struct clocksource clocksource_hpet = {
  79         .name           = "hpet",
  80         .rating         = 250,
  81         .read           = read_hpet,
  82         .mask           = CLOCKSOURCE_MASK(64),
  83         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  84 };
  85 static struct clocksource *hpet_clocksource;
  86 #endif
  87
  88 /* A lock for concurrent access by app and isr hpet activity. */
  89 static DEFINE_SPINLOCK(hpet_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         unsigned int hd_flags;
 102         unsigned int hd_irq;
 103         unsigned int hd_hdwirq;
 104         char hd_name[HPET_DEV_NAME];
 105 };
 106
 107 struct hpets {
 108         struct hpets *hp_next;
 109         struct hpet __iomem *hp_hpet;
 110         unsigned long hp_hpet_phys;
 111         struct clocksource *hp_clocksource;
 112         unsigned long long hp_tick_freq;
 113         unsigned long hp_delta;
 114         unsigned int hp_ntimer;
 115         unsigned int hp_which;
 116         struct hpet_dev hp_dev[1];
 117 };
 118
 119 static struct hpets *hpets;
 120
 121 #define HPET_OPEN               0x0001
 122 #define HPET_IE                 0x0002  /* interrupt enabled */
 123 #define HPET_PERIODIC           0x0004
 124 #define HPET_SHARED_IRQ         0x0008
 125
 126
 127 #ifndef readq
 128 static inline unsigned long long readq(void __iomem *addr)
 129 {
 130         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 131 }
 132 #endif
 133
 134 #ifndef writeq
 135 static inline void writeq(unsigned long long v, void __iomem *addr)
 136 {
 137         writel(v & 0xffffffff, addr);
 138         writel(v >> 32, addr + 4);
 139 }
 140 #endif
 141
 142 static irqreturn_t hpet_interrupt(int irq, void *data)
 143 {
 144         struct hpet_dev *devp;
 145         unsigned long isr;
 146
 147         devp = data;
 148         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 149
 150         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 151             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 152                 return IRQ_NONE;
 153
 154         spin_lock(&hpet_lock);
 155         devp->hd_irqdata++;
 156
 157         /*
 158          * For non-periodic timers, increment the accumulator.
 159          * This has the effect of treating non-periodic like periodic.
 160          */
 161         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 162                 unsigned long m, t, mc, base, k;
 163                 struct hpet __iomem *hpet = devp->hd_hpet;
 164                 struct hpets *hpetp = devp->hd_hpets;
 165
 166                 t = devp->hd_ireqfreq;
 167                 m = read_counter(&devp->hd_timer->hpet_compare);
 168                 mc = read_counter(&hpet->hpet_mc);
 169                 /* The time for the next interrupt would logically be t + m,
 170                  * however, if we are very unlucky and the interrupt is delayed
 171                  * for longer than t then we will completely miss the next
 172                  * interrupt if we set t + m and an application will hang.
 173                  * Therefore we need to make a more complex computation assuming
 174                  * that there exists a k for which the following is true:
 175                  * k * t + base < mc + delta
 176                  * (k + 1) * t + base > mc + delta
 177                  * where t is the interval in hpet ticks for the given freq,
 178                  * base is the theoretical start value 0 < base < t,
 179                  * mc is the main counter value at the time of the interrupt,
 180                  * delta is the time it takes to write the a value to the
 181                  * comparator.
 182                  * k may then be computed as (mc - base + delta) / t .
 183                  */
 184                 base = mc % t;
 185                 k = (mc - base + hpetp->hp_delta) / t;
 186                 write_counter(t * (k + 1) + base,
 187                               &devp->hd_timer->hpet_compare);
 188         }
 189
 190         if (devp->hd_flags & HPET_SHARED_IRQ)
 191                 writel(isr, &devp->hd_hpet->hpet_isr);
 192         spin_unlock(&hpet_lock);
 193
 194         wake_up_interruptible(&devp->hd_waitqueue);
 195
 196         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 197
 198         return IRQ_HANDLED;
 199 }
 200
 201 static void hpet_timer_set_irq(struct hpet_dev *devp)
 202 {
 203         unsigned long v;
 204         int irq, gsi;
 205         struct hpet_timer __iomem *timer;
 206
 207         spin_lock_irq(&hpet_lock);
 208         if (devp->hd_hdwirq) {
 209                 spin_unlock_irq(&hpet_lock);
 210                 return;
 211         }
 212
 213         timer = devp->hd_timer;
 214
 215         /* we prefer level triggered mode */
 216         v = readl(&timer->hpet_config);
 217         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
 218                 v |= Tn_INT_TYPE_CNF_MASK;
 219                 writel(v, &timer->hpet_config);
 220         }
 221         spin_unlock_irq(&hpet_lock);
 222
 223         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
 224                                  Tn_INT_ROUTE_CAP_SHIFT;
 225
 226         /*
 227          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
 228          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
 229          */
 230         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 231                 v &= ~0xf3df;
 232         else
 233                 v &= ~0xffff;
 234
 235         for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
 236                 if (irq >= nr_irqs) {
 237                         irq = HPET_MAX_IRQ;
 238                         break;
 239                 }
 240
 241                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
 242                                         ACPI_ACTIVE_LOW);
 243                 if (gsi > 0)
 244                         break;
 245
 246                 /* FIXME: Setup interrupt source table */
 247         }
 248
 249         if (irq < HPET_MAX_IRQ) {
 250                 spin_lock_irq(&hpet_lock);
 251                 v = readl(&timer->hpet_config);
 252                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 253                 writel(v, &timer->hpet_config);
 254                 devp->hd_hdwirq = gsi;
 255                 spin_unlock_irq(&hpet_lock);
 256         }
 257         return;
 258 }
 259
 260 static int hpet_open(struct inode *inode, struct file *file)
 261 {
 262         struct hpet_dev *devp;
 263         struct hpets *hpetp;
 264         int i;
 265
 266         if (file->f_mode & FMODE_WRITE)
 267                 return -EINVAL;
 268
 269         mutex_lock(&hpet_mutex);
 270         spin_lock_irq(&hpet_lock);
 271
 272         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 273                 for (i = 0; i < hpetp->hp_ntimer; i++)
 274                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
 275                                 continue;
 276                         else {
 277                                 devp = &hpetp->hp_dev[i];
 278                                 break;
 279                         }
 280
 281         if (!devp) {
 282                 spin_unlock_irq(&hpet_lock);
 283                 mutex_unlock(&hpet_mutex);
 284                 return -EBUSY;
 285         }
 286
 287         file->private_data = devp;
 288         devp->hd_irqdata = 0;
 289         devp->hd_flags |= HPET_OPEN;
 290         spin_unlock_irq(&hpet_lock);
 291         mutex_unlock(&hpet_mutex);
 292
 293         hpet_timer_set_irq(devp);
 294
 295         return 0;
 296 }
 297
 298 static ssize_t
 299 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 300 {
 301         DECLARE_WAITQUEUE(wait, current);
 302         unsigned long data;
 303         ssize_t retval;
 304         struct hpet_dev *devp;
 305
 306         devp = file->private_data;
 307         if (!devp->hd_ireqfreq)
 308                 return -EIO;
 309
 310         if (count < sizeof(unsigned long))
 311                 return -EINVAL;
 312
 313         add_wait_queue(&devp->hd_waitqueue, &wait);
 314
 315         for ( ; ; ) {
 316                 set_current_state(TASK_INTERRUPTIBLE);
 317
 318                 spin_lock_irq(&hpet_lock);
 319                 data = devp->hd_irqdata;
 320                 devp->hd_irqdata = 0;
 321                 spin_unlock_irq(&hpet_lock);
 322
 323                 if (data)
 324                         break;
 325                 else if (file->f_flags & O_NONBLOCK) {
 326                         retval = -EAGAIN;
 327                         goto out;
 328                 } else if (signal_pending(current)) {
 329                         retval = -ERESTARTSYS;
 330                         goto out;
 331                 }
 332                 schedule();
 333         }
 334
 335         retval = put_user(data, (unsigned long __user *)buf);
 336         if (!retval)
 337                 retval = sizeof(unsigned long);
 338 out:
 339         __set_current_state(TASK_RUNNING);
 340         remove_wait_queue(&devp->hd_waitqueue, &wait);
 341
 342         return retval;
 343 }
 344
 345 static __poll_t hpet_poll(struct file *file, poll_table * wait)
 346 {
 347         unsigned long v;
 348         struct hpet_dev *devp;
 349
 350         devp = file->private_data;
 351
 352         if (!devp->hd_ireqfreq)
 353                 return 0;
 354
 355         poll_wait(file, &devp->hd_waitqueue, wait);
 356
 357         spin_lock_irq(&hpet_lock);
 358         v = devp->hd_irqdata;
 359         spin_unlock_irq(&hpet_lock);
 360
 361         if (v != 0)
 362                 return EPOLLIN | EPOLLRDNORM;
 363
 364         return 0;
 365 }
 366
 367 #ifdef CONFIG_HPET_MMAP
 368 #ifdef CONFIG_HPET_MMAP_DEFAULT
 369 static int hpet_mmap_enabled = 1;
 370 #else
 371 static int hpet_mmap_enabled = 0;
 372 #endif
 373
 374 static __init int hpet_mmap_enable(char *str)
 375 {
 376         get_option(&str, &hpet_mmap_enabled);
 377         pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
 378         return 1;
 379 }
 380 __setup("hpet_mmap", hpet_mmap_enable);
 381
 382 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 383 {
 384         struct hpet_dev *devp;
 385         unsigned long addr;
 386
 387         if (!hpet_mmap_enabled)
 388                 return -EACCES;
 389
 390         devp = file->private_data;
 391         addr = devp->hd_hpets->hp_hpet_phys;
 392
 393         if (addr & (PAGE_SIZE - 1))
 394                 return -ENOSYS;
 395
 396         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 397         return vm_iomap_memory(vma, addr, PAGE_SIZE);
 398 }
 399 #else
 400 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 401 {
 402         return -ENOSYS;
 403 }
 404 #endif
 405
 406 static int hpet_fasync(int fd, struct file *file, int on)
 407 {
 408         struct hpet_dev *devp;
 409
 410         devp = file->private_data;
 411
 412         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 413                 return 0;
 414         else
 415                 return -EIO;
 416 }
 417
 418 static int hpet_release(struct inode *inode, struct file *file)
 419 {
 420         struct hpet_dev *devp;
 421         struct hpet_timer __iomem *timer;
 422         int irq = 0;
 423
 424         devp = file->private_data;
 425         timer = devp->hd_timer;
 426
 427         spin_lock_irq(&hpet_lock);
 428
 429         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 430                &timer->hpet_config);
 431
 432         irq = devp->hd_irq;
 433         devp->hd_irq = 0;
 434
 435         devp->hd_ireqfreq = 0;
 436
 437         if (devp->hd_flags & HPET_PERIODIC
 438             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 439                 unsigned long v;
 440
 441                 v = readq(&timer->hpet_config);
 442                 v ^= Tn_TYPE_CNF_MASK;
 443                 writeq(v, &timer->hpet_config);
 444         }
 445
 446         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 447         spin_unlock_irq(&hpet_lock);
 448
 449         if (irq)
 450                 free_irq(irq, devp);
 451
 452         file->private_data = NULL;
 453         return 0;
 454 }
 455
 456 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 457 {
 458         struct hpet_timer __iomem *timer;
 459         struct hpet __iomem *hpet;
 460         struct hpets *hpetp;
 461         int irq;
 462         unsigned long g, v, t, m;
 463         unsigned long flags, isr;
 464
 465         timer = devp->hd_timer;
 466         hpet = devp->hd_hpet;
 467         hpetp = devp->hd_hpets;
 468
 469         if (!devp->hd_ireqfreq)
 470                 return -EIO;
 471
 472         spin_lock_irq(&hpet_lock);
 473
 474         if (devp->hd_flags & HPET_IE) {
 475                 spin_unlock_irq(&hpet_lock);
 476                 return -EBUSY;
 477         }
 478
 479         devp->hd_flags |= HPET_IE;
 480
 481         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 482                 devp->hd_flags |= HPET_SHARED_IRQ;
 483         spin_unlock_irq(&hpet_lock);
 484
 485         irq = devp->hd_hdwirq;
 486
 487         if (irq) {
 488                 unsigned long irq_flags;
 489
 490                 if (devp->hd_flags & HPET_SHARED_IRQ) {
 491                         /*
 492                          * To prevent the interrupt handler from seeing an
 493                          * unwanted interrupt status bit, program the timer
 494                          * so that it will not fire in the near future ...
 495                          */
 496                         writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
 497                                &timer->hpet_config);
 498                         write_counter(read_counter(&hpet->hpet_mc),
 499                                       &timer->hpet_compare);
 500                         /* ... and clear any left-over status. */
 501                         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 502                         writel(isr, &hpet->hpet_isr);
 503                 }
 504
 505                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 506                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
 507                 if (request_irq(irq, hpet_interrupt, irq_flags,
 508                                 devp->hd_name, (void *)devp)) {
 509                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 510                         irq = 0;
 511                 }
 512         }
 513
 514         if (irq == 0) {
 515                 spin_lock_irq(&hpet_lock);
 516                 devp->hd_flags ^= HPET_IE;
 517                 spin_unlock_irq(&hpet_lock);
 518                 return -EIO;
 519         }
 520
 521         devp->hd_irq = irq;
 522         t = devp->hd_ireqfreq;
 523         v = readq(&timer->hpet_config);
 524
 525         /* 64-bit comparators are not yet supported through the ioctls,
 526          * so force this into 32-bit mode if it supports both modes
 527          */
 528         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 529
 530         if (devp->hd_flags & HPET_PERIODIC) {
 531                 g |= Tn_TYPE_CNF_MASK;
 532                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 533                 writeq(v, &timer->hpet_config);
 534                 local_irq_save(flags);
 535
 536                 /*
 537                  * NOTE: First we modify the hidden accumulator
 538                  * register supported by periodic-capable comparators.
 539                  * We never want to modify the (single) counter; that
 540                  * would affect all the comparators. The value written
 541                  * is the counter value when the first interrupt is due.
 542                  */
 543                 m = read_counter(&hpet->hpet_mc);
 544                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 545                 /*
 546                  * Then we modify the comparator, indicating the period
 547                  * for subsequent interrupt.
 548                  */
 549                 write_counter(t, &timer->hpet_compare);
 550         } else {
 551                 local_irq_save(flags);
 552                 m = read_counter(&hpet->hpet_mc);
 553                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 554         }
 555
 556         if (devp->hd_flags & HPET_SHARED_IRQ) {
 557                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 558                 writel(isr, &hpet->hpet_isr);
 559         }
 560         writeq(g, &timer->hpet_config);
 561         local_irq_restore(flags);
 562
 563         return 0;
 564 }
 565
 566 /* converts Hz to number of timer ticks */
 567 static inline unsigned long hpet_time_div(struct hpets *hpets,
 568                                           unsigned long dis)
 569 {
 570         unsigned long long m;
 571
 572         m = hpets->hp_tick_freq + (dis >> 1);
 573         do_div(m, dis);
 574         return (unsigned long)m;
 575 }
 576
 577 static int
 578 hpet_ioctl_common(struct hpet_dev *devp, unsigned int cmd, unsigned long arg,
 579                   struct hpet_info *info)
 580 {
 581         struct hpet_timer __iomem *timer;
 582         struct hpets *hpetp;
 583         int err;
 584         unsigned long v;
 585
 586         switch (cmd) {
 587         case HPET_IE_OFF:
 588         case HPET_INFO:
 589         case HPET_EPI:
 590         case HPET_DPI:
 591         case HPET_IRQFREQ:
 592                 timer = devp->hd_timer;
 593                 hpetp = devp->hd_hpets;
 594                 break;
 595         case HPET_IE_ON:
 596                 return hpet_ioctl_ieon(devp);
 597         default:
 598                 return -EINVAL;
 599         }
 600
 601         err = 0;
 602
 603         switch (cmd) {
 604         case HPET_IE_OFF:
 605                 if ((devp->hd_flags & HPET_IE) == 0)
 606                         break;
 607                 v = readq(&timer->hpet_config);
 608                 v &= ~Tn_INT_ENB_CNF_MASK;
 609                 writeq(v, &timer->hpet_config);
 610                 if (devp->hd_irq) {
 611                         free_irq(devp->hd_irq, devp);
 612                         devp->hd_irq = 0;
 613                 }
 614                 devp->hd_flags ^= HPET_IE;
 615                 break;
 616         case HPET_INFO:
 617                 {
 618                         memset(info, 0, sizeof(*info));
 619                         if (devp->hd_ireqfreq)
 620                                 info->hi_ireqfreq =
 621                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 622                         info->hi_flags =
 623                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 624                         info->hi_hpet = hpetp->hp_which;
 625                         info->hi_timer = devp - hpetp->hp_dev;
 626                         break;
 627                 }
 628         case HPET_EPI:
 629                 v = readq(&timer->hpet_config);
 630                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 631                         err = -ENXIO;
 632                         break;
 633                 }
 634                 devp->hd_flags |= HPET_PERIODIC;
 635                 break;
 636         case HPET_DPI:
 637                 v = readq(&timer->hpet_config);
 638                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 639                         err = -ENXIO;
 640                         break;
 641                 }
 642                 if (devp->hd_flags & HPET_PERIODIC &&
 643                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 644                         v = readq(&timer->hpet_config);
 645                         v ^= Tn_TYPE_CNF_MASK;
 646                         writeq(v, &timer->hpet_config);
 647                 }
 648                 devp->hd_flags &= ~HPET_PERIODIC;
 649                 break;
 650         case HPET_IRQFREQ:
 651                 if ((arg > hpet_max_freq) &&
 652                     !capable(CAP_SYS_RESOURCE)) {
 653                         err = -EACCES;
 654                         break;
 655                 }
 656
 657                 if (!arg) {
 658                         err = -EINVAL;
 659                         break;
 660                 }
 661
 662                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 663         }
 664
 665         return err;
 666 }
 667
 668 static long
 669 hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 670 {
 671         struct hpet_info info;
 672         int err;
 673
 674         mutex_lock(&hpet_mutex);
 675         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 676         mutex_unlock(&hpet_mutex);
 677
 678         if ((cmd == HPET_INFO) && !err &&
 679             (copy_to_user((void __user *)arg, &info, sizeof(info))))
 680                 err = -EFAULT;
 681
 682         return err;
 683 }
 684
 685 #ifdef CONFIG_COMPAT
 686 struct compat_hpet_info {
 687         compat_ulong_t hi_ireqfreq;     /* Hz */
 688         compat_ulong_t hi_flags;        /* information */
 689         unsigned short hi_hpet;
 690         unsigned short hi_timer;
 691 };
 692
 693 static long
 694 hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 695 {
 696         struct hpet_info info;
 697         int err;
 698
 699         mutex_lock(&hpet_mutex);
 700         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 701         mutex_unlock(&hpet_mutex);
 702
 703         if ((cmd == HPET_INFO) && !err) {
 704                 struct compat_hpet_info __user *u = compat_ptr(arg);
 705                 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
 706                     put_user(info.hi_flags, &u->hi_flags) ||
 707                     put_user(info.hi_hpet, &u->hi_hpet) ||
 708                     put_user(info.hi_timer, &u->hi_timer))
 709                         err = -EFAULT;
 710         }
 711
 712         return err;
 713 }
 714 #endif
 715
 716 static const struct file_operations hpet_fops = {
 717         .owner = THIS_MODULE,
 718         .llseek = no_llseek,
 719         .read = hpet_read,
 720         .poll = hpet_poll,
 721         .unlocked_ioctl = hpet_ioctl,
 722 #ifdef CONFIG_COMPAT
 723         .compat_ioctl = hpet_compat_ioctl,
 724 #endif
 725         .open = hpet_open,
 726         .release = hpet_release,
 727         .fasync = hpet_fasync,
 728         .mmap = hpet_mmap,
 729 };
 730
 731 static int hpet_is_known(struct hpet_data *hdp)
 732 {
 733         struct hpets *hpetp;
 734
 735         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 736                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 737                         return 1;
 738
 739         return 0;
 740 }
 741
 742 static struct ctl_table hpet_table[] = {
 743         {
 744          .procname = "max-user-freq",
 745          .data = &hpet_max_freq,
 746          .maxlen = sizeof(int),
 747          .mode = 0644,
 748          .proc_handler = proc_dointvec,
 749          },
 750         {}
 751 };
 752
 753 static struct ctl_table hpet_root[] = {
 754         {
 755          .procname = "hpet",
 756          .maxlen = 0,
 757          .mode = 0555,
 758          .child = hpet_table,
 759          },
 760         {}
 761 };
 762
 763 static struct ctl_table dev_root[] = {
 764         {
 765          .procname = "dev",
 766          .maxlen = 0,
 767          .mode = 0555,
 768          .child = hpet_root,
 769          },
 770         {}
 771 };
 772
 773 static struct ctl_table_header *sysctl_header;
 774
 775 /*
 776  * Adjustment for when arming the timer with
 777  * initial conditions.  That is, main counter
 778  * ticks expired before interrupts are enabled.
 779  */
 780 #define TICK_CALIBRATE  (1000UL)
 781
 782 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 783 {
 784         struct hpet_timer __iomem *timer = NULL;
 785         unsigned long t, m, count, i, flags, start;
 786         struct hpet_dev *devp;
 787         int j;
 788         struct hpet __iomem *hpet;
 789
 790         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 791                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 792                         timer = devp->hd_timer;
 793                         break;
 794                 }
 795
 796         if (!timer)
 797                 return 0;
 798
 799         hpet = hpetp->hp_hpet;
 800         t = read_counter(&timer->hpet_compare);
 801
 802         i = 0;
 803         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 804
 805         local_irq_save(flags);
 806
 807         start = read_counter(&hpet->hpet_mc);
 808
 809         do {
 810                 m = read_counter(&hpet->hpet_mc);
 811                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 812         } while (i++, (m - start) < count);
 813
 814         local_irq_restore(flags);
 815
 816         return (m - start) / i;
 817 }
 818
 819 static unsigned long hpet_calibrate(struct hpets *hpetp)
 820 {
 821         unsigned long ret = ~0UL;
 822         unsigned long tmp;
 823
 824         /*
 825          * Try to calibrate until return value becomes stable small value.
 826          * If SMI interruption occurs in calibration loop, the return value
 827          * will be big. This avoids its impact.
 828          */
 829         for ( ; ; ) {
 830                 tmp = __hpet_calibrate(hpetp);
 831                 if (ret <= tmp)
 832                         break;
 833                 ret = tmp;
 834         }
 835
 836         return ret;
 837 }
 838
 839 int hpet_alloc(struct hpet_data *hdp)
 840 {
 841         u64 cap, mcfg;
 842         struct hpet_dev *devp;
 843         u32 i, ntimer;
 844         struct hpets *hpetp;
 845         size_t siz;
 846         struct hpet __iomem *hpet;
 847         static struct hpets *last;
 848         unsigned long period;
 849         unsigned long long temp;
 850         u32 remainder;
 851
 852         /*
 853          * hpet_alloc can be called by platform dependent code.
 854          * If platform dependent code has allocated the hpet that
 855          * ACPI has also reported, then we catch it here.
 856          */
 857         if (hpet_is_known(hdp)) {
 858                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 859                         __func__);
 860                 return 0;
 861         }
 862
 863         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 864                                       sizeof(struct hpet_dev));
 865
 866         hpetp = kzalloc(siz, GFP_KERNEL);
 867
 868         if (!hpetp)
 869                 return -ENOMEM;
 870
 871         hpetp->hp_which = hpet_nhpet++;
 872         hpetp->hp_hpet = hdp->hd_address;
 873         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 874
 875         hpetp->hp_ntimer = hdp->hd_nirqs;
 876
 877         for (i = 0; i < hdp->hd_nirqs; i++)
 878                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 879
 880         hpet = hpetp->hp_hpet;
 881
 882         cap = readq(&hpet->hpet_cap);
 883
 884         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 885
 886         if (hpetp->hp_ntimer != ntimer) {
 887                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 888                        " with number of timers\n");
 889                 kfree(hpetp);
 890                 return -ENODEV;
 891         }
 892
 893         if (last)
 894                 last->hp_next = hpetp;
 895         else
 896                 hpets = hpetp;
 897
 898         last = hpetp;
 899
 900         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 901                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 902         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 903         temp += period >> 1; /* round */
 904         do_div(temp, period);
 905         hpetp->hp_tick_freq = temp; /* ticks per second */
 906
 907         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 908                 hpetp->hp_which, hdp->hd_phys_address,
 909                 hpetp->hp_ntimer > 1 ? "s" : "");
 910         for (i = 0; i < hpetp->hp_ntimer; i++)
 911                 printk(KERN_CONT "%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 912         printk(KERN_CONT "\n");
 913
 914         temp = hpetp->hp_tick_freq;
 915         remainder = do_div(temp, 1000000);
 916         printk(KERN_INFO
 917                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 918                 hpetp->hp_which, hpetp->hp_ntimer,
 919                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 920                 (unsigned) temp, remainder);
 921
 922         mcfg = readq(&hpet->hpet_config);
 923         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 924                 write_counter(0L, &hpet->hpet_mc);
 925                 mcfg |= HPET_ENABLE_CNF_MASK;
 926                 writeq(mcfg, &hpet->hpet_config);
 927         }
 928
 929         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 930                 struct hpet_timer __iomem *timer;
 931
 932                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 933
 934                 devp->hd_hpets = hpetp;
 935                 devp->hd_hpet = hpet;
 936                 devp->hd_timer = timer;
 937
 938                 /*
 939                  * If the timer was reserved by platform code,
 940                  * then make timer unavailable for opens.
 941                  */
 942                 if (hdp->hd_state & (1 << i)) {
 943                         devp->hd_flags = HPET_OPEN;
 944                         continue;
 945                 }
 946
 947                 init_waitqueue_head(&devp->hd_waitqueue);
 948         }
 949
 950         hpetp->hp_delta = hpet_calibrate(hpetp);
 951
 952 /* This clocksource driver currently only works on ia64 */
 953 #ifdef CONFIG_IA64
 954         if (!hpet_clocksource) {
 955                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 956                 clocksource_hpet.archdata.fsys_mmio = hpet_mctr;
 957                 clocksource_register_hz(&clocksource_hpet, hpetp->hp_tick_freq);
 958                 hpetp->hp_clocksource = &clocksource_hpet;
 959                 hpet_clocksource = &clocksource_hpet;
 960         }
 961 #endif
 962
 963         return 0;
 964 }
 965
 966 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 967 {
 968         struct hpet_data *hdp;
 969         acpi_status status;
 970         struct acpi_resource_address64 addr;
 971
 972         hdp = data;
 973
 974         status = acpi_resource_to_address64(res, &addr);
 975
 976         if (ACPI_SUCCESS(status)) {
 977                 hdp->hd_phys_address = addr.address.minimum;
 978                 hdp->hd_address = ioremap(addr.address.minimum, addr.address.address_length);
 979
 980                 if (hpet_is_known(hdp)) {
 981                         iounmap(hdp->hd_address);
 982                         return AE_ALREADY_EXISTS;
 983                 }
 984         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 985                 struct acpi_resource_fixed_memory32 *fixmem32;
 986
 987                 fixmem32 = &res->data.fixed_memory32;
 988
 989                 hdp->hd_phys_address = fixmem32->address;
 990                 hdp->hd_address = ioremap(fixmem32->address,
 991                                                 HPET_RANGE_SIZE);
 992
 993                 if (hpet_is_known(hdp)) {
 994                         iounmap(hdp->hd_address);
 995                         return AE_ALREADY_EXISTS;
 996                 }
 997         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 998                 struct acpi_resource_extended_irq *irqp;
 999                 int i, irq;
1000
1001                 irqp = &res->data.extended_irq;
1002
1003                 for (i = 0; i < irqp->interrupt_count; i++) {
1004                         if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
1005                                 break;
1006
1007                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
1008                                       irqp->triggering, irqp->polarity);
1009                         if (irq < 0)
1010                                 return AE_ERROR;
1011
1012                         hdp->hd_irq[hdp->hd_nirqs] = irq;
1013                         hdp->hd_nirqs++;
1014                 }
1015         }
1016
1017         return AE_OK;
1018 }
1019
1020 static int hpet_acpi_add(struct acpi_device *device)
1021 {
1022         acpi_status result;
1023         struct hpet_data data;
1024
1025         memset(&data, 0, sizeof(data));
1026
1027         result =
1028             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
1029                                 hpet_resources, &data);
1030
1031         if (ACPI_FAILURE(result))
1032                 return -ENODEV;
1033
1034         if (!data.hd_address || !data.hd_nirqs) {
1035                 if (data.hd_address)
1036                         iounmap(data.hd_address);
1037                 printk("%s: no address or irqs in _CRS\n", __func__);
1038                 return -ENODEV;
1039         }
1040
1041         return hpet_alloc(&data);
1042 }
1043
1044 static const struct acpi_device_id hpet_device_ids[] = {
1045         {"PNP0103", 0},
1046         {"", 0},
1047 };
1048
1049 static struct acpi_driver hpet_acpi_driver = {
1050         .name = "hpet",
1051         .ids = hpet_device_ids,
1052         .ops = {
1053                 .add = hpet_acpi_add,
1054                 },
1055 };
1056
1057 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1058
1059 static int __init hpet_init(void)
1060 {
1061         int result;
1062
1063         result = misc_register(&hpet_misc);
1064         if (result < 0)
1065                 return -ENODEV;
1066
1067         sysctl_header = register_sysctl_table(dev_root);
1068
1069         result = acpi_bus_register_driver(&hpet_acpi_driver);
1070         if (result < 0) {
1071                 if (sysctl_header)
1072                         unregister_sysctl_table(sysctl_header);
1073                 misc_deregister(&hpet_misc);
1074                 return result;
1075         }
1076
1077         return 0;
1078 }
1079 device_initcall(hpet_init);
1080
1081 /*
1082 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1083 MODULE_LICENSE("GPL");
1084 */