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 <[email protected]>
   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/poll.h>
  20 #include <linux/mm.h>
  21 #include <linux/proc_fs.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/sysctl.h>
  24 #include <linux/wait.h>
  25 #include <linux/sched/signal.h>
  26 #include <linux/bcd.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/bitops.h>
  29 #include <linux/compat.h>
  30 #include <linux/clocksource.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/slab.h>
  33 #include <linux/io.h>
  34 #include <linux/acpi.h>
  35 #include <linux/hpet.h>
  36 #include <asm/current.h>
  37 #include <asm/irq.h>
  38 #include <asm/div64.h>
  39
  40 /*
  41  * The High Precision Event Timer driver.
  42  * This driver is closely modelled after the rtc.c driver.
  43  * See HPET spec revision 1.
  44  */
  45 #define HPET_USER_FREQ  (64)
  46 #define HPET_DRIFT      (500)
  47
  48 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
  49
  50
  51 /* WARNING -- don't get confused.  These macros are never used
  52  * to write the (single) counter, and rarely to read it.
  53  * They're badly named; to fix, someday.
  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 DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
  64 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  65
  66 /* This clocksource driver currently only works on ia64 */
  67 #ifdef CONFIG_IA64
  68 static void __iomem *hpet_mctr;
  69
  70 static u64 read_hpet(struct clocksource *cs)
  71 {
  72         return (u64)read_counter((void __iomem *)hpet_mctr);
  73 }
  74
  75 static struct clocksource clocksource_hpet = {
  76         .name           = "hpet",
  77         .rating         = 250,
  78         .read           = read_hpet,
  79         .mask           = CLOCKSOURCE_MASK(64),
  80         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  81 };
  82 static struct clocksource *hpet_clocksource;
  83 #endif
  84
  85 /* A lock for concurrent access by app and isr hpet activity. */
  86 static DEFINE_SPINLOCK(hpet_lock);
  87
  88 #define HPET_DEV_NAME   (7)
  89
  90 struct hpet_dev {
  91         struct hpets *hd_hpets;
  92         struct hpet __iomem *hd_hpet;
  93         struct hpet_timer __iomem *hd_timer;
  94         unsigned long hd_ireqfreq;
  95         unsigned long hd_irqdata;
  96         wait_queue_head_t hd_waitqueue;
  97         struct fasync_struct *hd_async_queue;
  98         unsigned int hd_flags;
  99         unsigned int hd_irq;
 100         unsigned int hd_hdwirq;
 101         char hd_name[HPET_DEV_NAME];
 102 };
 103
 104 struct hpets {
 105         struct hpets *hp_next;
 106         struct hpet __iomem *hp_hpet;
 107         unsigned long hp_hpet_phys;
 108         struct clocksource *hp_clocksource;
 109         unsigned long long hp_tick_freq;
 110         unsigned long hp_delta;
 111         unsigned int hp_ntimer;
 112         unsigned int hp_which;
 113         struct hpet_dev hp_dev[];
 114 };
 115
 116 static struct hpets *hpets;
 117
 118 #define HPET_OPEN               0x0001
 119 #define HPET_IE                 0x0002  /* interrupt enabled */
 120 #define HPET_PERIODIC           0x0004
 121 #define HPET_SHARED_IRQ         0x0008
 122
 123
 124 #ifndef readq
 125 static inline unsigned long long readq(void __iomem *addr)
 126 {
 127         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 128 }
 129 #endif
 130
 131 #ifndef writeq
 132 static inline void writeq(unsigned long long v, void __iomem *addr)
 133 {
 134         writel(v & 0xffffffff, addr);
 135         writel(v >> 32, addr + 4);
 136 }
 137 #endif
 138
 139 static irqreturn_t hpet_interrupt(int irq, void *data)
 140 {
 141         struct hpet_dev *devp;
 142         unsigned long isr;
 143
 144         devp = data;
 145         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 146
 147         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 148             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 149                 return IRQ_NONE;
 150
 151         spin_lock(&hpet_lock);
 152         devp->hd_irqdata++;
 153
 154         /*
 155          * For non-periodic timers, increment the accumulator.
 156          * This has the effect of treating non-periodic like periodic.
 157          */
 158         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 159                 unsigned long t, mc, base, k;
 160                 struct hpet __iomem *hpet = devp->hd_hpet;
 161                 struct hpets *hpetp = devp->hd_hpets;
 162
 163                 t = devp->hd_ireqfreq;
 164                 read_counter(&devp->hd_timer->hpet_compare);
 165                 mc = read_counter(&hpet->hpet_mc);
 166                 /* The time for the next interrupt would logically be t + m,
 167                  * however, if we are very unlucky and the interrupt is delayed
 168                  * for longer than t then we will completely miss the next
 169                  * interrupt if we set t + m and an application will hang.
 170                  * Therefore we need to make a more complex computation assuming
 171                  * that there exists a k for which the following is true:
 172                  * k * t + base < mc + delta
 173                  * (k + 1) * t + base > mc + delta
 174                  * where t is the interval in hpet ticks for the given freq,
 175                  * base is the theoretical start value 0 < base < t,
 176                  * mc is the main counter value at the time of the interrupt,
 177                  * delta is the time it takes to write the a value to the
 178                  * comparator.
 179                  * k may then be computed as (mc - base + delta) / t .
 180                  */
 181                 base = mc % t;
 182                 k = (mc - base + hpetp->hp_delta) / t;
 183                 write_counter(t * (k + 1) + base,
 184                               &devp->hd_timer->hpet_compare);
 185         }
 186
 187         if (devp->hd_flags & HPET_SHARED_IRQ)
 188                 writel(isr, &devp->hd_hpet->hpet_isr);
 189         spin_unlock(&hpet_lock);
 190
 191         wake_up_interruptible(&devp->hd_waitqueue);
 192
 193         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 194
 195         return IRQ_HANDLED;
 196 }
 197
 198 static void hpet_timer_set_irq(struct hpet_dev *devp)
 199 {
 200         unsigned long v;
 201         int irq, gsi;
 202         struct hpet_timer __iomem *timer;
 203
 204         spin_lock_irq(&hpet_lock);
 205         if (devp->hd_hdwirq) {
 206                 spin_unlock_irq(&hpet_lock);
 207                 return;
 208         }
 209
 210         timer = devp->hd_timer;
 211
 212         /* we prefer level triggered mode */
 213         v = readl(&timer->hpet_config);
 214         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
 215                 v |= Tn_INT_TYPE_CNF_MASK;
 216                 writel(v, &timer->hpet_config);
 217         }
 218         spin_unlock_irq(&hpet_lock);
 219
 220         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
 221                                  Tn_INT_ROUTE_CAP_SHIFT;
 222
 223         /*
 224          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
 225          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
 226          */
 227         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 228                 v &= ~0xf3df;
 229         else
 230                 v &= ~0xffff;
 231
 232         for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
 233                 if (irq >= nr_irqs) {
 234                         irq = HPET_MAX_IRQ;
 235                         break;
 236                 }
 237
 238                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
 239                                         ACPI_ACTIVE_LOW);
 240                 if (gsi > 0)
 241                         break;
 242
 243                 /* FIXME: Setup interrupt source table */
 244         }
 245
 246         if (irq < HPET_MAX_IRQ) {
 247                 spin_lock_irq(&hpet_lock);
 248                 v = readl(&timer->hpet_config);
 249                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 250                 writel(v, &timer->hpet_config);
 251                 devp->hd_hdwirq = gsi;
 252                 spin_unlock_irq(&hpet_lock);
 253         }
 254         return;
 255 }
 256
 257 static int hpet_open(struct inode *inode, struct file *file)
 258 {
 259         struct hpet_dev *devp;
 260         struct hpets *hpetp;
 261         int i;
 262
 263         if (file->f_mode & FMODE_WRITE)
 264                 return -EINVAL;
 265
 266         mutex_lock(&hpet_mutex);
 267         spin_lock_irq(&hpet_lock);
 268
 269         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 270                 for (i = 0; i < hpetp->hp_ntimer; i++)
 271                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
 272                                 continue;
 273                         else {
 274                                 devp = &hpetp->hp_dev[i];
 275                                 break;
 276                         }
 277
 278         if (!devp) {
 279                 spin_unlock_irq(&hpet_lock);
 280                 mutex_unlock(&hpet_mutex);
 281                 return -EBUSY;
 282         }
 283
 284         file->private_data = devp;
 285         devp->hd_irqdata = 0;
 286         devp->hd_flags |= HPET_OPEN;
 287         spin_unlock_irq(&hpet_lock);
 288         mutex_unlock(&hpet_mutex);
 289
 290         hpet_timer_set_irq(devp);
 291
 292         return 0;
 293 }
 294
 295 static ssize_t
 296 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 297 {
 298         DECLARE_WAITQUEUE(wait, current);
 299         unsigned long data;
 300         ssize_t retval;
 301         struct hpet_dev *devp;
 302
 303         devp = file->private_data;
 304         if (!devp->hd_ireqfreq)
 305                 return -EIO;
 306
 307         if (count < sizeof(unsigned long))
 308                 return -EINVAL;
 309
 310         add_wait_queue(&devp->hd_waitqueue, &wait);
 311
 312         for ( ; ; ) {
 313                 set_current_state(TASK_INTERRUPTIBLE);
 314
 315                 spin_lock_irq(&hpet_lock);
 316                 data = devp->hd_irqdata;
 317                 devp->hd_irqdata = 0;
 318                 spin_unlock_irq(&hpet_lock);
 319
 320                 if (data)
 321                         break;
 322                 else if (file->f_flags & O_NONBLOCK) {
 323                         retval = -EAGAIN;
 324                         goto out;
 325                 } else if (signal_pending(current)) {
 326                         retval = -ERESTARTSYS;
 327                         goto out;
 328                 }
 329                 schedule();
 330         }
 331
 332         retval = put_user(data, (unsigned long __user *)buf);
 333         if (!retval)
 334                 retval = sizeof(unsigned long);
 335 out:
 336         __set_current_state(TASK_RUNNING);
 337         remove_wait_queue(&devp->hd_waitqueue, &wait);
 338
 339         return retval;
 340 }
 341
 342 static __poll_t hpet_poll(struct file *file, poll_table * wait)
 343 {
 344         unsigned long v;
 345         struct hpet_dev *devp;
 346
 347         devp = file->private_data;
 348
 349         if (!devp->hd_ireqfreq)
 350                 return 0;
 351
 352         poll_wait(file, &devp->hd_waitqueue, wait);
 353
 354         spin_lock_irq(&hpet_lock);
 355         v = devp->hd_irqdata;
 356         spin_unlock_irq(&hpet_lock);
 357
 358         if (v != 0)
 359                 return EPOLLIN | EPOLLRDNORM;
 360
 361         return 0;
 362 }
 363
 364 #ifdef CONFIG_HPET_MMAP
 365 #ifdef CONFIG_HPET_MMAP_DEFAULT
 366 static int hpet_mmap_enabled = 1;
 367 #else
 368 static int hpet_mmap_enabled = 0;
 369 #endif
 370
 371 static __init int hpet_mmap_enable(char *str)
 372 {
 373         get_option(&str, &hpet_mmap_enabled);
 374         pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
 375         return 1;
 376 }
 377 __setup("hpet_mmap=", hpet_mmap_enable);
 378
 379 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 380 {
 381         struct hpet_dev *devp;
 382         unsigned long addr;
 383
 384         if (!hpet_mmap_enabled)
 385                 return -EACCES;
 386
 387         devp = file->private_data;
 388         addr = devp->hd_hpets->hp_hpet_phys;
 389
 390         if (addr & (PAGE_SIZE - 1))
 391                 return -ENOSYS;
 392
 393         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 394         return vm_iomap_memory(vma, addr, PAGE_SIZE);
 395 }
 396 #else
 397 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 398 {
 399         return -ENOSYS;
 400 }
 401 #endif
 402
 403 static int hpet_fasync(int fd, struct file *file, int on)
 404 {
 405         struct hpet_dev *devp;
 406
 407         devp = file->private_data;
 408
 409         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 410                 return 0;
 411         else
 412                 return -EIO;
 413 }
 414
 415 static int hpet_release(struct inode *inode, struct file *file)
 416 {
 417         struct hpet_dev *devp;
 418         struct hpet_timer __iomem *timer;
 419         int irq = 0;
 420
 421         devp = file->private_data;
 422         timer = devp->hd_timer;
 423
 424         spin_lock_irq(&hpet_lock);
 425
 426         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 427                &timer->hpet_config);
 428
 429         irq = devp->hd_irq;
 430         devp->hd_irq = 0;
 431
 432         devp->hd_ireqfreq = 0;
 433
 434         if (devp->hd_flags & HPET_PERIODIC
 435             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 436                 unsigned long v;
 437
 438                 v = readq(&timer->hpet_config);
 439                 v ^= Tn_TYPE_CNF_MASK;
 440                 writeq(v, &timer->hpet_config);
 441         }
 442
 443         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 444         spin_unlock_irq(&hpet_lock);
 445
 446         if (irq)
 447                 free_irq(irq, devp);
 448
 449         file->private_data = NULL;
 450         return 0;
 451 }
 452
 453 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 454 {
 455         struct hpet_timer __iomem *timer;
 456         struct hpet __iomem *hpet;
 457         struct hpets *hpetp;
 458         int irq;
 459         unsigned long g, v, t, m;
 460         unsigned long flags, isr;
 461
 462         timer = devp->hd_timer;
 463         hpet = devp->hd_hpet;
 464         hpetp = devp->hd_hpets;
 465
 466         if (!devp->hd_ireqfreq)
 467                 return -EIO;
 468
 469         spin_lock_irq(&hpet_lock);
 470
 471         if (devp->hd_flags & HPET_IE) {
 472                 spin_unlock_irq(&hpet_lock);
 473                 return -EBUSY;
 474         }
 475
 476         devp->hd_flags |= HPET_IE;
 477
 478         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 479                 devp->hd_flags |= HPET_SHARED_IRQ;
 480         spin_unlock_irq(&hpet_lock);
 481
 482         irq = devp->hd_hdwirq;
 483
 484         if (irq) {
 485                 unsigned long irq_flags;
 486
 487                 if (devp->hd_flags & HPET_SHARED_IRQ) {
 488                         /*
 489                          * To prevent the interrupt handler from seeing an
 490                          * unwanted interrupt status bit, program the timer
 491                          * so that it will not fire in the near future ...
 492                          */
 493                         writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
 494                                &timer->hpet_config);
 495                         write_counter(read_counter(&hpet->hpet_mc),
 496                                       &timer->hpet_compare);
 497                         /* ... and clear any left-over status. */
 498                         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 499                         writel(isr, &hpet->hpet_isr);
 500                 }
 501
 502                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 503                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
 504                 if (request_irq(irq, hpet_interrupt, irq_flags,
 505                                 devp->hd_name, (void *)devp)) {
 506                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 507                         irq = 0;
 508                 }
 509         }
 510
 511         if (irq == 0) {
 512                 spin_lock_irq(&hpet_lock);
 513                 devp->hd_flags ^= HPET_IE;
 514                 spin_unlock_irq(&hpet_lock);
 515                 return -EIO;
 516         }
 517
 518         devp->hd_irq = irq;
 519         t = devp->hd_ireqfreq;
 520         v = readq(&timer->hpet_config);
 521
 522         /* 64-bit comparators are not yet supported through the ioctls,
 523          * so force this into 32-bit mode if it supports both modes
 524          */
 525         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 526
 527         if (devp->hd_flags & HPET_PERIODIC) {
 528                 g |= Tn_TYPE_CNF_MASK;
 529                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 530                 writeq(v, &timer->hpet_config);
 531                 local_irq_save(flags);
 532
 533                 /*
 534                  * NOTE: First we modify the hidden accumulator
 535                  * register supported by periodic-capable comparators.
 536                  * We never want to modify the (single) counter; that
 537                  * would affect all the comparators. The value written
 538                  * is the counter value when the first interrupt is due.
 539                  */
 540                 m = read_counter(&hpet->hpet_mc);
 541                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 542                 /*
 543                  * Then we modify the comparator, indicating the period
 544                  * for subsequent interrupt.
 545                  */
 546                 write_counter(t, &timer->hpet_compare);
 547         } else {
 548                 local_irq_save(flags);
 549                 m = read_counter(&hpet->hpet_mc);
 550                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 551         }
 552
 553         if (devp->hd_flags & HPET_SHARED_IRQ) {
 554                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 555                 writel(isr, &hpet->hpet_isr);
 556         }
 557         writeq(g, &timer->hpet_config);
 558         local_irq_restore(flags);
 559
 560         return 0;
 561 }
 562
 563 /* converts Hz to number of timer ticks */
 564 static inline unsigned long hpet_time_div(struct hpets *hpets,
 565                                           unsigned long dis)
 566 {
 567         unsigned long long m;
 568
 569         m = hpets->hp_tick_freq + (dis >> 1);
 570         return div64_ul(m, dis);
 571 }
 572
 573 static int
 574 hpet_ioctl_common(struct hpet_dev *devp, unsigned int cmd, unsigned long arg,
 575                   struct hpet_info *info)
 576 {
 577         struct hpet_timer __iomem *timer;
 578         struct hpets *hpetp;
 579         int err;
 580         unsigned long v;
 581
 582         switch (cmd) {
 583         case HPET_IE_OFF:
 584         case HPET_INFO:
 585         case HPET_EPI:
 586         case HPET_DPI:
 587         case HPET_IRQFREQ:
 588                 timer = devp->hd_timer;
 589                 hpetp = devp->hd_hpets;
 590                 break;
 591         case HPET_IE_ON:
 592                 return hpet_ioctl_ieon(devp);
 593         default:
 594                 return -EINVAL;
 595         }
 596
 597         err = 0;
 598
 599         switch (cmd) {
 600         case HPET_IE_OFF:
 601                 if ((devp->hd_flags & HPET_IE) == 0)
 602                         break;
 603                 v = readq(&timer->hpet_config);
 604                 v &= ~Tn_INT_ENB_CNF_MASK;
 605                 writeq(v, &timer->hpet_config);
 606                 if (devp->hd_irq) {
 607                         free_irq(devp->hd_irq, devp);
 608                         devp->hd_irq = 0;
 609                 }
 610                 devp->hd_flags ^= HPET_IE;
 611                 break;
 612         case HPET_INFO:
 613                 {
 614                         memset(info, 0, sizeof(*info));
 615                         if (devp->hd_ireqfreq)
 616                                 info->hi_ireqfreq =
 617                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 618                         info->hi_flags =
 619                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 620                         info->hi_hpet = hpetp->hp_which;
 621                         info->hi_timer = devp - hpetp->hp_dev;
 622                         break;
 623                 }
 624         case HPET_EPI:
 625                 v = readq(&timer->hpet_config);
 626                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 627                         err = -ENXIO;
 628                         break;
 629                 }
 630                 devp->hd_flags |= HPET_PERIODIC;
 631                 break;
 632         case HPET_DPI:
 633                 v = readq(&timer->hpet_config);
 634                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 635                         err = -ENXIO;
 636                         break;
 637                 }
 638                 if (devp->hd_flags & HPET_PERIODIC &&
 639                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 640                         v = readq(&timer->hpet_config);
 641                         v ^= Tn_TYPE_CNF_MASK;
 642                         writeq(v, &timer->hpet_config);
 643                 }
 644                 devp->hd_flags &= ~HPET_PERIODIC;
 645                 break;
 646         case HPET_IRQFREQ:
 647                 if ((arg > hpet_max_freq) &&
 648                     !capable(CAP_SYS_RESOURCE)) {
 649                         err = -EACCES;
 650                         break;
 651                 }
 652
 653                 if (!arg) {
 654                         err = -EINVAL;
 655                         break;
 656                 }
 657
 658                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 659         }
 660
 661         return err;
 662 }
 663
 664 static long
 665 hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 666 {
 667         struct hpet_info info;
 668         int err;
 669
 670         mutex_lock(&hpet_mutex);
 671         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 672         mutex_unlock(&hpet_mutex);
 673
 674         if ((cmd == HPET_INFO) && !err &&
 675             (copy_to_user((void __user *)arg, &info, sizeof(info))))
 676                 err = -EFAULT;
 677
 678         return err;
 679 }
 680
 681 #ifdef CONFIG_COMPAT
 682 struct compat_hpet_info {
 683         compat_ulong_t hi_ireqfreq;     /* Hz */
 684         compat_ulong_t hi_flags;        /* information */
 685         unsigned short hi_hpet;
 686         unsigned short hi_timer;
 687 };
 688
 689 static long
 690 hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 691 {
 692         struct hpet_info info;
 693         int err;
 694
 695         mutex_lock(&hpet_mutex);
 696         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 697         mutex_unlock(&hpet_mutex);
 698
 699         if ((cmd == HPET_INFO) && !err) {
 700                 struct compat_hpet_info __user *u = compat_ptr(arg);
 701                 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
 702                     put_user(info.hi_flags, &u->hi_flags) ||
 703                     put_user(info.hi_hpet, &u->hi_hpet) ||
 704                     put_user(info.hi_timer, &u->hi_timer))
 705                         err = -EFAULT;
 706         }
 707
 708         return err;
 709 }
 710 #endif
 711
 712 static const struct file_operations hpet_fops = {
 713         .owner = THIS_MODULE,
 714         .llseek = no_llseek,
 715         .read = hpet_read,
 716         .poll = hpet_poll,
 717         .unlocked_ioctl = hpet_ioctl,
 718 #ifdef CONFIG_COMPAT
 719         .compat_ioctl = hpet_compat_ioctl,
 720 #endif
 721         .open = hpet_open,
 722         .release = hpet_release,
 723         .fasync = hpet_fasync,
 724         .mmap = hpet_mmap,
 725 };
 726
 727 static int hpet_is_known(struct hpet_data *hdp)
 728 {
 729         struct hpets *hpetp;
 730
 731         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 732                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 733                         return 1;
 734
 735         return 0;
 736 }
 737
 738 static struct ctl_table hpet_table[] = {
 739         {
 740          .procname = "max-user-freq",
 741          .data = &hpet_max_freq,
 742          .maxlen = sizeof(int),
 743          .mode = 0644,
 744          .proc_handler = proc_dointvec,
 745          },
 746         {}
 747 };
 748
 749 static struct ctl_table_header *sysctl_header;
 750
 751 /*
 752  * Adjustment for when arming the timer with
 753  * initial conditions.  That is, main counter
 754  * ticks expired before interrupts are enabled.
 755  */
 756 #define TICK_CALIBRATE  (1000UL)
 757
 758 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 759 {
 760         struct hpet_timer __iomem *timer = NULL;
 761         unsigned long t, m, count, i, flags, start;
 762         struct hpet_dev *devp;
 763         int j;
 764         struct hpet __iomem *hpet;
 765
 766         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 767                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 768                         timer = devp->hd_timer;
 769                         break;
 770                 }
 771
 772         if (!timer)
 773                 return 0;
 774
 775         hpet = hpetp->hp_hpet;
 776         t = read_counter(&timer->hpet_compare);
 777
 778         i = 0;
 779         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 780
 781         local_irq_save(flags);
 782
 783         start = read_counter(&hpet->hpet_mc);
 784
 785         do {
 786                 m = read_counter(&hpet->hpet_mc);
 787                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 788         } while (i++, (m - start) < count);
 789
 790         local_irq_restore(flags);
 791
 792         return (m - start) / i;
 793 }
 794
 795 static unsigned long hpet_calibrate(struct hpets *hpetp)
 796 {
 797         unsigned long ret = ~0UL;
 798         unsigned long tmp;
 799
 800         /*
 801          * Try to calibrate until return value becomes stable small value.
 802          * If SMI interruption occurs in calibration loop, the return value
 803          * will be big. This avoids its impact.
 804          */
 805         for ( ; ; ) {
 806                 tmp = __hpet_calibrate(hpetp);
 807                 if (ret <= tmp)
 808                         break;
 809                 ret = tmp;
 810         }
 811
 812         return ret;
 813 }
 814
 815 int hpet_alloc(struct hpet_data *hdp)
 816 {
 817         u64 cap, mcfg;
 818         struct hpet_dev *devp;
 819         u32 i, ntimer;
 820         struct hpets *hpetp;
 821         struct hpet __iomem *hpet;
 822         static struct hpets *last;
 823         unsigned long period;
 824         unsigned long long temp;
 825         u32 remainder;
 826
 827         /*
 828          * hpet_alloc can be called by platform dependent code.
 829          * If platform dependent code has allocated the hpet that
 830          * ACPI has also reported, then we catch it here.
 831          */
 832         if (hpet_is_known(hdp)) {
 833                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 834                         __func__);
 835                 return 0;
 836         }
 837
 838         hpetp = kzalloc(struct_size(hpetp, hp_dev, hdp->hd_nirqs),
 839                         GFP_KERNEL);
 840
 841         if (!hpetp)
 842                 return -ENOMEM;
 843
 844         hpetp->hp_which = hpet_nhpet++;
 845         hpetp->hp_hpet = hdp->hd_address;
 846         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 847
 848         hpetp->hp_ntimer = hdp->hd_nirqs;
 849
 850         for (i = 0; i < hdp->hd_nirqs; i++)
 851                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 852
 853         hpet = hpetp->hp_hpet;
 854
 855         cap = readq(&hpet->hpet_cap);
 856
 857         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 858
 859         if (hpetp->hp_ntimer != ntimer) {
 860                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 861                        " with number of timers\n");
 862                 kfree(hpetp);
 863                 return -ENODEV;
 864         }
 865
 866         if (last)
 867                 last->hp_next = hpetp;
 868         else
 869                 hpets = hpetp;
 870
 871         last = hpetp;
 872
 873         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 874                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 875         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 876         temp += period >> 1; /* round */
 877         do_div(temp, period);
 878         hpetp->hp_tick_freq = temp; /* ticks per second */
 879
 880         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 881                 hpetp->hp_which, hdp->hd_phys_address,
 882                 hpetp->hp_ntimer > 1 ? "s" : "");
 883         for (i = 0; i < hpetp->hp_ntimer; i++)
 884                 printk(KERN_CONT "%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 885         printk(KERN_CONT "\n");
 886
 887         temp = hpetp->hp_tick_freq;
 888         remainder = do_div(temp, 1000000);
 889         printk(KERN_INFO
 890                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 891                 hpetp->hp_which, hpetp->hp_ntimer,
 892                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 893                 (unsigned) temp, remainder);
 894
 895         mcfg = readq(&hpet->hpet_config);
 896         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 897                 write_counter(0L, &hpet->hpet_mc);
 898                 mcfg |= HPET_ENABLE_CNF_MASK;
 899                 writeq(mcfg, &hpet->hpet_config);
 900         }
 901
 902         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 903                 struct hpet_timer __iomem *timer;
 904
 905                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 906
 907                 devp->hd_hpets = hpetp;
 908                 devp->hd_hpet = hpet;
 909                 devp->hd_timer = timer;
 910
 911                 /*
 912                  * If the timer was reserved by platform code,
 913                  * then make timer unavailable for opens.
 914                  */
 915                 if (hdp->hd_state & (1 << i)) {
 916                         devp->hd_flags = HPET_OPEN;
 917                         continue;
 918                 }
 919
 920                 init_waitqueue_head(&devp->hd_waitqueue);
 921         }
 922
 923         hpetp->hp_delta = hpet_calibrate(hpetp);
 924
 925 /* This clocksource driver currently only works on ia64 */
 926 #ifdef CONFIG_IA64
 927         if (!hpet_clocksource) {
 928                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 929                 clocksource_hpet.archdata.fsys_mmio = hpet_mctr;
 930                 clocksource_register_hz(&clocksource_hpet, hpetp->hp_tick_freq);
 931                 hpetp->hp_clocksource = &clocksource_hpet;
 932                 hpet_clocksource = &clocksource_hpet;
 933         }
 934 #endif
 935
 936         return 0;
 937 }
 938
 939 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 940 {
 941         struct hpet_data *hdp;
 942         acpi_status status;
 943         struct acpi_resource_address64 addr;
 944
 945         hdp = data;
 946
 947         status = acpi_resource_to_address64(res, &addr);
 948
 949         if (ACPI_SUCCESS(status)) {
 950                 hdp->hd_phys_address = addr.address.minimum;
 951                 hdp->hd_address = ioremap(addr.address.minimum, addr.address.address_length);
 952                 if (!hdp->hd_address)
 953                         return AE_ERROR;
 954
 955                 if (hpet_is_known(hdp)) {
 956                         iounmap(hdp->hd_address);
 957                         return AE_ALREADY_EXISTS;
 958                 }
 959         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 960                 struct acpi_resource_fixed_memory32 *fixmem32;
 961
 962                 fixmem32 = &res->data.fixed_memory32;
 963
 964                 hdp->hd_phys_address = fixmem32->address;
 965                 hdp->hd_address = ioremap(fixmem32->address,
 966                                                 HPET_RANGE_SIZE);
 967                 if (!hdp->hd_address)
 968                         return AE_ERROR;
 969
 970                 if (hpet_is_known(hdp)) {
 971                         iounmap(hdp->hd_address);
 972                         return AE_ALREADY_EXISTS;
 973                 }
 974         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 975                 struct acpi_resource_extended_irq *irqp;
 976                 int i, irq;
 977
 978                 irqp = &res->data.extended_irq;
 979
 980                 for (i = 0; i < irqp->interrupt_count; i++) {
 981                         if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
 982                                 break;
 983
 984                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
 985                                       irqp->triggering, irqp->polarity);
 986                         if (irq < 0)
 987                                 return AE_ERROR;
 988
 989                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 990                         hdp->hd_nirqs++;
 991                 }
 992         }
 993
 994         return AE_OK;
 995 }
 996
 997 static int hpet_acpi_add(struct acpi_device *device)
 998 {
 999         acpi_status result;
1000         struct hpet_data data;
1001
1002         memset(&data, 0, sizeof(data));
1003
1004         result =
1005             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
1006                                 hpet_resources, &data);
1007
1008         if (ACPI_FAILURE(result))
1009                 return -ENODEV;
1010
1011         if (!data.hd_address || !data.hd_nirqs) {
1012                 if (data.hd_address)
1013                         iounmap(data.hd_address);
1014                 printk("%s: no address or irqs in _CRS\n", __func__);
1015                 return -ENODEV;
1016         }
1017
1018         return hpet_alloc(&data);
1019 }
1020
1021 static const struct acpi_device_id hpet_device_ids[] = {
1022         {"PNP0103", 0},
1023         {"", 0},
1024 };
1025
1026 static struct acpi_driver hpet_acpi_driver = {
1027         .name = "hpet",
1028         .ids = hpet_device_ids,
1029         .ops = {
1030                 .add = hpet_acpi_add,
1031                 },
1032 };
1033
1034 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1035
1036 static int __init hpet_init(void)
1037 {
1038         int result;
1039
1040         result = misc_register(&hpet_misc);
1041         if (result < 0)
1042                 return -ENODEV;
1043
1044         sysctl_header = register_sysctl("dev/hpet", hpet_table);
1045
1046         result = acpi_bus_register_driver(&hpet_acpi_driver);
1047         if (result < 0) {
1048                 if (sysctl_header)
1049                         unregister_sysctl_table(sysctl_header);
1050                 misc_deregister(&hpet_misc);
1051                 return result;
1052         }
1053
1054         return 0;
1055 }
1056 device_initcall(hpet_init);
1057
1058 /*
1059 MODULE_AUTHOR("Bob Picco <[email protected]>");
1060 MODULE_LICENSE("GPL");
1061 */