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/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         unsigned long long hp_tick_freq;
  91         unsigned long hp_delta;
  92         unsigned int hp_ntimer;
  93         unsigned int hp_which;
  94         struct hpet_dev hp_dev[] __counted_by(hp_ntimer);
  95 };
  96
  97 static struct hpets *hpets;
  98
  99 #define HPET_OPEN               0x0001
 100 #define HPET_IE                 0x0002  /* interrupt enabled */
 101 #define HPET_PERIODIC           0x0004
 102 #define HPET_SHARED_IRQ         0x0008
 103
 104 static irqreturn_t hpet_interrupt(int irq, void *data)
 105 {
 106         struct hpet_dev *devp;
 107         unsigned long isr;
 108
 109         devp = data;
 110         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 111
 112         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 113             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 114                 return IRQ_NONE;
 115
 116         spin_lock(&hpet_lock);
 117         devp->hd_irqdata++;
 118
 119         /*
 120          * For non-periodic timers, increment the accumulator.
 121          * This has the effect of treating non-periodic like periodic.
 122          */
 123         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 124                 unsigned long t, mc, base, k;
 125                 struct hpet __iomem *hpet = devp->hd_hpet;
 126                 struct hpets *hpetp = devp->hd_hpets;
 127
 128                 t = devp->hd_ireqfreq;
 129                 read_counter(&devp->hd_timer->hpet_compare);
 130                 mc = read_counter(&hpet->hpet_mc);
 131                 /* The time for the next interrupt would logically be t + m,
 132                  * however, if we are very unlucky and the interrupt is delayed
 133                  * for longer than t then we will completely miss the next
 134                  * interrupt if we set t + m and an application will hang.
 135                  * Therefore we need to make a more complex computation assuming
 136                  * that there exists a k for which the following is true:
 137                  * k * t + base < mc + delta
 138                  * (k + 1) * t + base > mc + delta
 139                  * where t is the interval in hpet ticks for the given freq,
 140                  * base is the theoretical start value 0 < base < t,
 141                  * mc is the main counter value at the time of the interrupt,
 142                  * delta is the time it takes to write the a value to the
 143                  * comparator.
 144                  * k may then be computed as (mc - base + delta) / t .
 145                  */
 146                 base = mc % t;
 147                 k = (mc - base + hpetp->hp_delta) / t;
 148                 write_counter(t * (k + 1) + base,
 149                               &devp->hd_timer->hpet_compare);
 150         }
 151
 152         if (devp->hd_flags & HPET_SHARED_IRQ)
 153                 writel(isr, &devp->hd_hpet->hpet_isr);
 154         spin_unlock(&hpet_lock);
 155
 156         wake_up_interruptible(&devp->hd_waitqueue);
 157
 158         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 159
 160         return IRQ_HANDLED;
 161 }
 162
 163 static void hpet_timer_set_irq(struct hpet_dev *devp)
 164 {
 165         unsigned long v;
 166         int irq, gsi;
 167         struct hpet_timer __iomem *timer;
 168
 169         spin_lock_irq(&hpet_lock);
 170         if (devp->hd_hdwirq) {
 171                 spin_unlock_irq(&hpet_lock);
 172                 return;
 173         }
 174
 175         timer = devp->hd_timer;
 176
 177         /* we prefer level triggered mode */
 178         v = readl(&timer->hpet_config);
 179         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
 180                 v |= Tn_INT_TYPE_CNF_MASK;
 181                 writel(v, &timer->hpet_config);
 182         }
 183         spin_unlock_irq(&hpet_lock);
 184
 185         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
 186                                  Tn_INT_ROUTE_CAP_SHIFT;
 187
 188         /*
 189          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
 190          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
 191          */
 192         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 193                 v &= ~0xf3df;
 194         else
 195                 v &= ~0xffff;
 196
 197         for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
 198                 if (irq >= nr_irqs) {
 199                         irq = HPET_MAX_IRQ;
 200                         break;
 201                 }
 202
 203                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
 204                                         ACPI_ACTIVE_LOW);
 205                 if (gsi > 0)
 206                         break;
 207
 208                 /* FIXME: Setup interrupt source table */
 209         }
 210
 211         if (irq < HPET_MAX_IRQ) {
 212                 spin_lock_irq(&hpet_lock);
 213                 v = readl(&timer->hpet_config);
 214                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 215                 writel(v, &timer->hpet_config);
 216                 devp->hd_hdwirq = gsi;
 217                 spin_unlock_irq(&hpet_lock);
 218         }
 219         return;
 220 }
 221
 222 static int hpet_open(struct inode *inode, struct file *file)
 223 {
 224         struct hpet_dev *devp;
 225         struct hpets *hpetp;
 226         int i;
 227
 228         if (file->f_mode & FMODE_WRITE)
 229                 return -EINVAL;
 230
 231         mutex_lock(&hpet_mutex);
 232         spin_lock_irq(&hpet_lock);
 233
 234         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 235                 for (i = 0; i < hpetp->hp_ntimer; i++)
 236                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN) {
 237                                 continue;
 238                         } else {
 239                                 devp = &hpetp->hp_dev[i];
 240                                 break;
 241                         }
 242
 243         if (!devp) {
 244                 spin_unlock_irq(&hpet_lock);
 245                 mutex_unlock(&hpet_mutex);
 246                 return -EBUSY;
 247         }
 248
 249         file->private_data = devp;
 250         devp->hd_irqdata = 0;
 251         devp->hd_flags |= HPET_OPEN;
 252         spin_unlock_irq(&hpet_lock);
 253         mutex_unlock(&hpet_mutex);
 254
 255         hpet_timer_set_irq(devp);
 256
 257         return 0;
 258 }
 259
 260 static ssize_t
 261 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 262 {
 263         DECLARE_WAITQUEUE(wait, current);
 264         unsigned long data;
 265         ssize_t retval;
 266         struct hpet_dev *devp;
 267
 268         devp = file->private_data;
 269         if (!devp->hd_ireqfreq)
 270                 return -EIO;
 271
 272         if (in_compat_syscall()) {
 273                 if (count < sizeof(compat_ulong_t))
 274                         return -EINVAL;
 275         } else {
 276                 if (count < sizeof(unsigned long))
 277                         return -EINVAL;
 278         }
 279
 280         add_wait_queue(&devp->hd_waitqueue, &wait);
 281
 282         for ( ; ; ) {
 283                 set_current_state(TASK_INTERRUPTIBLE);
 284
 285                 spin_lock_irq(&hpet_lock);
 286                 data = devp->hd_irqdata;
 287                 devp->hd_irqdata = 0;
 288                 spin_unlock_irq(&hpet_lock);
 289
 290                 if (data) {
 291                         break;
 292                 } else if (file->f_flags & O_NONBLOCK) {
 293                         retval = -EAGAIN;
 294                         goto out;
 295                 } else if (signal_pending(current)) {
 296                         retval = -ERESTARTSYS;
 297                         goto out;
 298                 }
 299                 schedule();
 300         }
 301
 302         if (in_compat_syscall()) {
 303                 retval = put_user(data, (compat_ulong_t __user *)buf);
 304                 if (!retval)
 305                         retval = sizeof(compat_ulong_t);
 306         } else {
 307                 retval = put_user(data, (unsigned long __user *)buf);
 308                 if (!retval)
 309                         retval = sizeof(unsigned long);
 310         }
 311
 312 out:
 313         __set_current_state(TASK_RUNNING);
 314         remove_wait_queue(&devp->hd_waitqueue, &wait);
 315
 316         return retval;
 317 }
 318
 319 static __poll_t hpet_poll(struct file *file, poll_table * wait)
 320 {
 321         unsigned long v;
 322         struct hpet_dev *devp;
 323
 324         devp = file->private_data;
 325
 326         if (!devp->hd_ireqfreq)
 327                 return 0;
 328
 329         poll_wait(file, &devp->hd_waitqueue, wait);
 330
 331         spin_lock_irq(&hpet_lock);
 332         v = devp->hd_irqdata;
 333         spin_unlock_irq(&hpet_lock);
 334
 335         if (v != 0)
 336                 return EPOLLIN | EPOLLRDNORM;
 337
 338         return 0;
 339 }
 340
 341 #ifdef CONFIG_HPET_MMAP
 342 #ifdef CONFIG_HPET_MMAP_DEFAULT
 343 static int hpet_mmap_enabled = 1;
 344 #else
 345 static int hpet_mmap_enabled = 0;
 346 #endif
 347
 348 static __init int hpet_mmap_enable(char *str)
 349 {
 350         get_option(&str, &hpet_mmap_enabled);
 351         pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
 352         return 1;
 353 }
 354 __setup("hpet_mmap=", hpet_mmap_enable);
 355
 356 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 357 {
 358         struct hpet_dev *devp;
 359         unsigned long addr;
 360
 361         if (!hpet_mmap_enabled)
 362                 return -EACCES;
 363
 364         devp = file->private_data;
 365         addr = devp->hd_hpets->hp_hpet_phys;
 366
 367         if (addr & (PAGE_SIZE - 1))
 368                 return -ENOSYS;
 369
 370         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 371         return vm_iomap_memory(vma, addr, PAGE_SIZE);
 372 }
 373 #else
 374 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 375 {
 376         return -ENOSYS;
 377 }
 378 #endif
 379
 380 static int hpet_fasync(int fd, struct file *file, int on)
 381 {
 382         struct hpet_dev *devp;
 383
 384         devp = file->private_data;
 385
 386         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 387                 return 0;
 388         else
 389                 return -EIO;
 390 }
 391
 392 static int hpet_release(struct inode *inode, struct file *file)
 393 {
 394         struct hpet_dev *devp;
 395         struct hpet_timer __iomem *timer;
 396         int irq = 0;
 397
 398         devp = file->private_data;
 399         timer = devp->hd_timer;
 400
 401         spin_lock_irq(&hpet_lock);
 402
 403         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 404                &timer->hpet_config);
 405
 406         irq = devp->hd_irq;
 407         devp->hd_irq = 0;
 408
 409         devp->hd_ireqfreq = 0;
 410
 411         if (devp->hd_flags & HPET_PERIODIC
 412             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 413                 unsigned long v;
 414
 415                 v = readq(&timer->hpet_config);
 416                 v ^= Tn_TYPE_CNF_MASK;
 417                 writeq(v, &timer->hpet_config);
 418         }
 419
 420         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 421         spin_unlock_irq(&hpet_lock);
 422
 423         if (irq)
 424                 free_irq(irq, devp);
 425
 426         file->private_data = NULL;
 427         return 0;
 428 }
 429
 430 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 431 {
 432         struct hpet_timer __iomem *timer;
 433         struct hpet __iomem *hpet;
 434         struct hpets *hpetp;
 435         int irq;
 436         unsigned long g, v, t, m;
 437         unsigned long flags, isr;
 438
 439         timer = devp->hd_timer;
 440         hpet = devp->hd_hpet;
 441         hpetp = devp->hd_hpets;
 442
 443         if (!devp->hd_ireqfreq)
 444                 return -EIO;
 445
 446         spin_lock_irq(&hpet_lock);
 447
 448         if (devp->hd_flags & HPET_IE) {
 449                 spin_unlock_irq(&hpet_lock);
 450                 return -EBUSY;
 451         }
 452
 453         devp->hd_flags |= HPET_IE;
 454
 455         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 456                 devp->hd_flags |= HPET_SHARED_IRQ;
 457         spin_unlock_irq(&hpet_lock);
 458
 459         irq = devp->hd_hdwirq;
 460
 461         if (irq) {
 462                 unsigned long irq_flags;
 463
 464                 if (devp->hd_flags & HPET_SHARED_IRQ) {
 465                         /*
 466                          * To prevent the interrupt handler from seeing an
 467                          * unwanted interrupt status bit, program the timer
 468                          * so that it will not fire in the near future ...
 469                          */
 470                         writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
 471                                &timer->hpet_config);
 472                         write_counter(read_counter(&hpet->hpet_mc),
 473                                       &timer->hpet_compare);
 474                         /* ... and clear any left-over status. */
 475                         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 476                         writel(isr, &hpet->hpet_isr);
 477                 }
 478
 479                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 480                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
 481                 if (request_irq(irq, hpet_interrupt, irq_flags,
 482                                 devp->hd_name, (void *)devp)) {
 483                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 484                         irq = 0;
 485                 }
 486         }
 487
 488         if (irq == 0) {
 489                 spin_lock_irq(&hpet_lock);
 490                 devp->hd_flags ^= HPET_IE;
 491                 spin_unlock_irq(&hpet_lock);
 492                 return -EIO;
 493         }
 494
 495         devp->hd_irq = irq;
 496         t = devp->hd_ireqfreq;
 497         v = readq(&timer->hpet_config);
 498
 499         /* 64-bit comparators are not yet supported through the ioctls,
 500          * so force this into 32-bit mode if it supports both modes
 501          */
 502         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 503
 504         if (devp->hd_flags & HPET_PERIODIC) {
 505                 g |= Tn_TYPE_CNF_MASK;
 506                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 507                 writeq(v, &timer->hpet_config);
 508                 local_irq_save(flags);
 509
 510                 /*
 511                  * NOTE: First we modify the hidden accumulator
 512                  * register supported by periodic-capable comparators.
 513                  * We never want to modify the (single) counter; that
 514                  * would affect all the comparators. The value written
 515                  * is the counter value when the first interrupt is due.
 516                  */
 517                 m = read_counter(&hpet->hpet_mc);
 518                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 519                 /*
 520                  * Then we modify the comparator, indicating the period
 521                  * for subsequent interrupt.
 522                  */
 523                 write_counter(t, &timer->hpet_compare);
 524         } else {
 525                 local_irq_save(flags);
 526                 m = read_counter(&hpet->hpet_mc);
 527                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 528         }
 529
 530         if (devp->hd_flags & HPET_SHARED_IRQ) {
 531                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 532                 writel(isr, &hpet->hpet_isr);
 533         }
 534         writeq(g, &timer->hpet_config);
 535         local_irq_restore(flags);
 536
 537         return 0;
 538 }
 539
 540 /* converts Hz to number of timer ticks */
 541 static inline unsigned long hpet_time_div(struct hpets *hpets,
 542                                           unsigned long dis)
 543 {
 544         unsigned long long m;
 545
 546         m = hpets->hp_tick_freq + (dis >> 1);
 547         return div64_ul(m, dis);
 548 }
 549
 550 static int
 551 hpet_ioctl_common(struct hpet_dev *devp, unsigned int cmd, unsigned long arg,
 552                   struct hpet_info *info)
 553 {
 554         struct hpet_timer __iomem *timer;
 555         struct hpets *hpetp;
 556         int err;
 557         unsigned long v;
 558
 559         switch (cmd) {
 560         case HPET_IE_OFF:
 561         case HPET_INFO:
 562         case HPET_EPI:
 563         case HPET_DPI:
 564         case HPET_IRQFREQ:
 565                 timer = devp->hd_timer;
 566                 hpetp = devp->hd_hpets;
 567                 break;
 568         case HPET_IE_ON:
 569                 return hpet_ioctl_ieon(devp);
 570         default:
 571                 return -EINVAL;
 572         }
 573
 574         err = 0;
 575
 576         switch (cmd) {
 577         case HPET_IE_OFF:
 578                 if ((devp->hd_flags & HPET_IE) == 0)
 579                         break;
 580                 v = readq(&timer->hpet_config);
 581                 v &= ~Tn_INT_ENB_CNF_MASK;
 582                 writeq(v, &timer->hpet_config);
 583                 if (devp->hd_irq) {
 584                         free_irq(devp->hd_irq, devp);
 585                         devp->hd_irq = 0;
 586                 }
 587                 devp->hd_flags ^= HPET_IE;
 588                 break;
 589         case HPET_INFO:
 590                 {
 591                         memset(info, 0, sizeof(*info));
 592                         if (devp->hd_ireqfreq)
 593                                 info->hi_ireqfreq =
 594                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 595                         info->hi_flags =
 596                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 597                         info->hi_hpet = hpetp->hp_which;
 598                         info->hi_timer = devp - hpetp->hp_dev;
 599                         break;
 600                 }
 601         case HPET_EPI:
 602                 v = readq(&timer->hpet_config);
 603                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 604                         err = -ENXIO;
 605                         break;
 606                 }
 607                 devp->hd_flags |= HPET_PERIODIC;
 608                 break;
 609         case HPET_DPI:
 610                 v = readq(&timer->hpet_config);
 611                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 612                         err = -ENXIO;
 613                         break;
 614                 }
 615                 if (devp->hd_flags & HPET_PERIODIC &&
 616                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 617                         v = readq(&timer->hpet_config);
 618                         v ^= Tn_TYPE_CNF_MASK;
 619                         writeq(v, &timer->hpet_config);
 620                 }
 621                 devp->hd_flags &= ~HPET_PERIODIC;
 622                 break;
 623         case HPET_IRQFREQ:
 624                 if ((arg > hpet_max_freq) &&
 625                     !capable(CAP_SYS_RESOURCE)) {
 626                         err = -EACCES;
 627                         break;
 628                 }
 629
 630                 if (!arg) {
 631                         err = -EINVAL;
 632                         break;
 633                 }
 634
 635                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 636         }
 637
 638         return err;
 639 }
 640
 641 static long
 642 hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 643 {
 644         struct hpet_info info;
 645         int err;
 646
 647         mutex_lock(&hpet_mutex);
 648         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 649         mutex_unlock(&hpet_mutex);
 650
 651         if ((cmd == HPET_INFO) && !err &&
 652             (copy_to_user((void __user *)arg, &info, sizeof(info))))
 653                 err = -EFAULT;
 654
 655         return err;
 656 }
 657
 658 #ifdef CONFIG_COMPAT
 659 struct compat_hpet_info {
 660         compat_ulong_t hi_ireqfreq;     /* Hz */
 661         compat_ulong_t hi_flags;        /* information */
 662         unsigned short hi_hpet;
 663         unsigned short hi_timer;
 664 };
 665
 666 /* 32-bit types would lead to different command codes which should be
 667  * translated into 64-bit ones before passed to hpet_ioctl_common
 668  */
 669 #define COMPAT_HPET_INFO       _IOR('h', 0x03, struct compat_hpet_info)
 670 #define COMPAT_HPET_IRQFREQ    _IOW('h', 0x6, compat_ulong_t)
 671
 672 static long
 673 hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 674 {
 675         struct hpet_info info;
 676         int err;
 677
 678         if (cmd == COMPAT_HPET_INFO)
 679                 cmd = HPET_INFO;
 680
 681         if (cmd == COMPAT_HPET_IRQFREQ)
 682                 cmd = HPET_IRQFREQ;
 683
 684         mutex_lock(&hpet_mutex);
 685         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 686         mutex_unlock(&hpet_mutex);
 687
 688         if ((cmd == HPET_INFO) && !err) {
 689                 struct compat_hpet_info __user *u = compat_ptr(arg);
 690                 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
 691                     put_user(info.hi_flags, &u->hi_flags) ||
 692                     put_user(info.hi_hpet, &u->hi_hpet) ||
 693                     put_user(info.hi_timer, &u->hi_timer))
 694                         err = -EFAULT;
 695         }
 696
 697         return err;
 698 }
 699 #endif
 700
 701 static const struct file_operations hpet_fops = {
 702         .owner = THIS_MODULE,
 703         .read = hpet_read,
 704         .poll = hpet_poll,
 705         .unlocked_ioctl = hpet_ioctl,
 706 #ifdef CONFIG_COMPAT
 707         .compat_ioctl = hpet_compat_ioctl,
 708 #endif
 709         .open = hpet_open,
 710         .release = hpet_release,
 711         .fasync = hpet_fasync,
 712         .mmap = hpet_mmap,
 713 };
 714
 715 static int hpet_is_known(struct hpet_data *hdp)
 716 {
 717         struct hpets *hpetp;
 718
 719         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 720                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 721                         return 1;
 722
 723         return 0;
 724 }
 725
 726 static struct ctl_table hpet_table[] = {
 727         {
 728          .procname = "max-user-freq",
 729          .data = &hpet_max_freq,
 730          .maxlen = sizeof(int),
 731          .mode = 0644,
 732          .proc_handler = proc_dointvec,
 733          },
 734 };
 735
 736 static struct ctl_table_header *sysctl_header;
 737
 738 /*
 739  * Adjustment for when arming the timer with
 740  * initial conditions.  That is, main counter
 741  * ticks expired before interrupts are enabled.
 742  */
 743 #define TICK_CALIBRATE  (1000UL)
 744
 745 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 746 {
 747         struct hpet_timer __iomem *timer = NULL;
 748         unsigned long t, m, count, i, flags, start;
 749         struct hpet_dev *devp;
 750         int j;
 751         struct hpet __iomem *hpet;
 752
 753         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 754                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 755                         timer = devp->hd_timer;
 756                         break;
 757                 }
 758
 759         if (!timer)
 760                 return 0;
 761
 762         hpet = hpetp->hp_hpet;
 763         t = read_counter(&timer->hpet_compare);
 764
 765         i = 0;
 766         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 767
 768         local_irq_save(flags);
 769
 770         start = read_counter(&hpet->hpet_mc);
 771
 772         do {
 773                 m = read_counter(&hpet->hpet_mc);
 774                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 775         } while (i++, (m - start) < count);
 776
 777         local_irq_restore(flags);
 778
 779         return (m - start) / i;
 780 }
 781
 782 static unsigned long hpet_calibrate(struct hpets *hpetp)
 783 {
 784         unsigned long ret = ~0UL;
 785         unsigned long tmp;
 786
 787         /*
 788          * Try to calibrate until return value becomes stable small value.
 789          * If SMI interruption occurs in calibration loop, the return value
 790          * will be big. This avoids its impact.
 791          */
 792         for ( ; ; ) {
 793                 tmp = __hpet_calibrate(hpetp);
 794                 if (ret <= tmp)
 795                         break;
 796                 ret = tmp;
 797         }
 798
 799         return ret;
 800 }
 801
 802 int hpet_alloc(struct hpet_data *hdp)
 803 {
 804         u64 cap, mcfg;
 805         struct hpet_dev *devp;
 806         u32 i, ntimer;
 807         struct hpets *hpetp;
 808         struct hpet __iomem *hpet;
 809         static struct hpets *last;
 810         u32 period;
 811         unsigned long long temp;
 812         u32 remainder;
 813
 814         /*
 815          * hpet_alloc can be called by platform dependent code.
 816          * If platform dependent code has allocated the hpet that
 817          * ACPI has also reported, then we catch it here.
 818          */
 819         if (hpet_is_known(hdp)) {
 820                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 821                         __func__);
 822                 return 0;
 823         }
 824
 825         hpetp = kzalloc(struct_size(hpetp, hp_dev, hdp->hd_nirqs),
 826                         GFP_KERNEL);
 827
 828         if (!hpetp)
 829                 return -ENOMEM;
 830
 831         hpetp->hp_which = hpet_nhpet++;
 832         hpetp->hp_hpet = hdp->hd_address;
 833         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 834
 835         hpetp->hp_ntimer = hdp->hd_nirqs;
 836
 837         for (i = 0; i < hdp->hd_nirqs; i++)
 838                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 839
 840         hpet = hpetp->hp_hpet;
 841
 842         cap = readq(&hpet->hpet_cap);
 843
 844         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 845
 846         if (hpetp->hp_ntimer != ntimer) {
 847                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 848                        " with number of timers\n");
 849                 kfree(hpetp);
 850                 return -ENODEV;
 851         }
 852
 853         if (last)
 854                 last->hp_next = hpetp;
 855         else
 856                 hpets = hpetp;
 857
 858         last = hpetp;
 859
 860         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 861                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 862         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 863         temp += period >> 1; /* round */
 864         do_div(temp, period);
 865         hpetp->hp_tick_freq = temp; /* ticks per second */
 866
 867         printk(KERN_INFO "hpet%u: at MMIO 0x%lx, IRQ%s",
 868                 hpetp->hp_which, hdp->hd_phys_address,
 869                 hpetp->hp_ntimer > 1 ? "s" : "");
 870         for (i = 0; i < hpetp->hp_ntimer; i++)
 871                 printk(KERN_CONT "%s %u", i > 0 ? "," : "", hdp->hd_irq[i]);
 872         printk(KERN_CONT "\n");
 873
 874         temp = hpetp->hp_tick_freq;
 875         remainder = do_div(temp, 1000000);
 876         printk(KERN_INFO
 877                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 878                 hpetp->hp_which, hpetp->hp_ntimer,
 879                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 880                 (unsigned) temp, remainder);
 881
 882         mcfg = readq(&hpet->hpet_config);
 883         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 884                 write_counter(0L, &hpet->hpet_mc);
 885                 mcfg |= HPET_ENABLE_CNF_MASK;
 886                 writeq(mcfg, &hpet->hpet_config);
 887         }
 888
 889         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 890                 struct hpet_timer __iomem *timer;
 891
 892                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 893
 894                 devp->hd_hpets = hpetp;
 895                 devp->hd_hpet = hpet;
 896                 devp->hd_timer = timer;
 897
 898                 /*
 899                  * If the timer was reserved by platform code,
 900                  * then make timer unavailable for opens.
 901                  */
 902                 if (hdp->hd_state & (1 << i)) {
 903                         devp->hd_flags = HPET_OPEN;
 904                         continue;
 905                 }
 906
 907                 init_waitqueue_head(&devp->hd_waitqueue);
 908         }
 909
 910         hpetp->hp_delta = hpet_calibrate(hpetp);
 911
 912         return 0;
 913 }
 914
 915 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 916 {
 917         struct hpet_data *hdp;
 918         acpi_status status;
 919         struct acpi_resource_address64 addr;
 920
 921         hdp = data;
 922
 923         status = acpi_resource_to_address64(res, &addr);
 924
 925         if (ACPI_SUCCESS(status)) {
 926                 hdp->hd_phys_address = addr.address.minimum;
 927                 hdp->hd_address = ioremap(addr.address.minimum, addr.address.address_length);
 928                 if (!hdp->hd_address)
 929                         return AE_ERROR;
 930
 931                 if (hpet_is_known(hdp)) {
 932                         iounmap(hdp->hd_address);
 933                         return AE_ALREADY_EXISTS;
 934                 }
 935         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 936                 struct acpi_resource_fixed_memory32 *fixmem32;
 937
 938                 fixmem32 = &res->data.fixed_memory32;
 939
 940                 hdp->hd_phys_address = fixmem32->address;
 941                 hdp->hd_address = ioremap(fixmem32->address,
 942                                                 HPET_RANGE_SIZE);
 943                 if (!hdp->hd_address)
 944                         return AE_ERROR;
 945
 946                 if (hpet_is_known(hdp)) {
 947                         iounmap(hdp->hd_address);
 948                         return AE_ALREADY_EXISTS;
 949                 }
 950         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 951                 struct acpi_resource_extended_irq *irqp;
 952                 int i, irq;
 953
 954                 irqp = &res->data.extended_irq;
 955
 956                 for (i = 0; i < irqp->interrupt_count; i++) {
 957                         if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
 958                                 break;
 959
 960                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
 961                                                 irqp->triggering,
 962                                                 irqp->polarity);
 963                         if (irq < 0)
 964                                 return AE_ERROR;
 965
 966                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 967                         hdp->hd_nirqs++;
 968                 }
 969         }
 970
 971         return AE_OK;
 972 }
 973
 974 static int hpet_acpi_add(struct acpi_device *device)
 975 {
 976         acpi_status result;
 977         struct hpet_data data;
 978
 979         memset(&data, 0, sizeof(data));
 980
 981         result =
 982             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 983                                 hpet_resources, &data);
 984
 985         if (ACPI_FAILURE(result))
 986                 return -ENODEV;
 987
 988         if (!data.hd_address || !data.hd_nirqs) {
 989                 if (data.hd_address)
 990                         iounmap(data.hd_address);
 991                 printk("%s: no address or irqs in _CRS\n", __func__);
 992                 return -ENODEV;
 993         }
 994
 995         return hpet_alloc(&data);
 996 }
 997
 998 static const struct acpi_device_id hpet_device_ids[] = {
 999         {"PNP0103", 0},
1000         {"", 0},
1001 };
1002
1003 static struct acpi_driver hpet_acpi_driver = {
1004         .name = "hpet",
1005         .ids = hpet_device_ids,
1006         .ops = {
1007                 .add = hpet_acpi_add,
1008                 },
1009 };
1010
1011 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1012
1013 static int __init hpet_init(void)
1014 {
1015         int result;
1016
1017         result = misc_register(&hpet_misc);
1018         if (result < 0)
1019                 return -ENODEV;
1020
1021         sysctl_header = register_sysctl("dev/hpet", hpet_table);
1022
1023         result = acpi_bus_register_driver(&hpet_acpi_driver);
1024         if (result < 0) {
1025                 if (sysctl_header)
1026                         unregister_sysctl_table(sysctl_header);
1027                 misc_deregister(&hpet_misc);
1028                 return result;
1029         }
1030
1031         return 0;
1032 }
1033 device_initcall(hpet_init);
1034
1035 /*
1036 MODULE_AUTHOR("Bob Picco <[email protected]>");
1037 MODULE_LICENSE("GPL");
1038 */