drivers/char/hpet.c

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