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         const unsigned int nr_irqs = irq_get_nr_irqs();
 166         unsigned long v;
 167         int irq, gsi;
 168         struct hpet_timer __iomem *timer;
 169
 170         spin_lock_irq(&hpet_lock);
 171         if (devp->hd_hdwirq) {
 172                 spin_unlock_irq(&hpet_lock);
 173                 return;
 174         }
 175
 176         timer = devp->hd_timer;
 177
 178         /* we prefer level triggered mode */
 179         v = readl(&timer->hpet_config);
 180         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
 181                 v |= Tn_INT_TYPE_CNF_MASK;
 182                 writel(v, &timer->hpet_config);
 183         }
 184         spin_unlock_irq(&hpet_lock);
 185
 186         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
 187                                  Tn_INT_ROUTE_CAP_SHIFT;
 188
 189         /*
 190          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
 191          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
 192          */
 193         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 194                 v &= ~0xf3df;
 195         else
 196                 v &= ~0xffff;
 197
 198         for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
 199                 if (irq >= nr_irqs) {
 200                         irq = HPET_MAX_IRQ;
 201                         break;
 202                 }
 203
 204                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
 205                                         ACPI_ACTIVE_LOW);
 206                 if (gsi > 0)
 207                         break;
 208
 209                 /* FIXME: Setup interrupt source table */
 210         }
 211
 212         if (irq < HPET_MAX_IRQ) {
 213                 spin_lock_irq(&hpet_lock);
 214                 v = readl(&timer->hpet_config);
 215                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 216                 writel(v, &timer->hpet_config);
 217                 devp->hd_hdwirq = gsi;
 218                 spin_unlock_irq(&hpet_lock);
 219         }
 220         return;
 221 }
 222
 223 static int hpet_open(struct inode *inode, struct file *file)
 224 {
 225         struct hpet_dev *devp;
 226         struct hpets *hpetp;
 227         int i;
 228
 229         if (file->f_mode & FMODE_WRITE)
 230                 return -EINVAL;
 231
 232         mutex_lock(&hpet_mutex);
 233         spin_lock_irq(&hpet_lock);
 234
 235         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 236                 for (i = 0; i < hpetp->hp_ntimer; i++)
 237                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN) {
 238                                 continue;
 239                         } else {
 240                                 devp = &hpetp->hp_dev[i];
 241                                 break;
 242                         }
 243
 244         if (!devp) {
 245                 spin_unlock_irq(&hpet_lock);
 246                 mutex_unlock(&hpet_mutex);
 247                 return -EBUSY;
 248         }
 249
 250         file->private_data = devp;
 251         devp->hd_irqdata = 0;
 252         devp->hd_flags |= HPET_OPEN;
 253         spin_unlock_irq(&hpet_lock);
 254         mutex_unlock(&hpet_mutex);
 255
 256         hpet_timer_set_irq(devp);
 257
 258         return 0;
 259 }
 260
 261 static ssize_t
 262 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 263 {
 264         DECLARE_WAITQUEUE(wait, current);
 265         unsigned long data;
 266         ssize_t retval;
 267         struct hpet_dev *devp;
 268
 269         devp = file->private_data;
 270         if (!devp->hd_ireqfreq)
 271                 return -EIO;
 272
 273         if (in_compat_syscall()) {
 274                 if (count < sizeof(compat_ulong_t))
 275                         return -EINVAL;
 276         } else {
 277                 if (count < sizeof(unsigned long))
 278                         return -EINVAL;
 279         }
 280
 281         add_wait_queue(&devp->hd_waitqueue, &wait);
 282
 283         for ( ; ; ) {
 284                 set_current_state(TASK_INTERRUPTIBLE);
 285
 286                 spin_lock_irq(&hpet_lock);
 287                 data = devp->hd_irqdata;
 288                 devp->hd_irqdata = 0;
 289                 spin_unlock_irq(&hpet_lock);
 290
 291                 if (data) {
 292                         break;
 293                 } else if (file->f_flags & O_NONBLOCK) {
 294                         retval = -EAGAIN;
 295                         goto out;
 296                 } else if (signal_pending(current)) {
 297                         retval = -ERESTARTSYS;
 298                         goto out;
 299                 }
 300                 schedule();
 301         }
 302
 303         if (in_compat_syscall()) {
 304                 retval = put_user(data, (compat_ulong_t __user *)buf);
 305                 if (!retval)
 306                         retval = sizeof(compat_ulong_t);
 307         } else {
 308                 retval = put_user(data, (unsigned long __user *)buf);
 309                 if (!retval)
 310                         retval = sizeof(unsigned long);
 311         }
 312
 313 out:
 314         __set_current_state(TASK_RUNNING);
 315         remove_wait_queue(&devp->hd_waitqueue, &wait);
 316
 317         return retval;
 318 }
 319
 320 static __poll_t hpet_poll(struct file *file, poll_table * wait)
 321 {
 322         unsigned long v;
 323         struct hpet_dev *devp;
 324
 325         devp = file->private_data;
 326
 327         if (!devp->hd_ireqfreq)
 328                 return 0;
 329
 330         poll_wait(file, &devp->hd_waitqueue, wait);
 331
 332         spin_lock_irq(&hpet_lock);
 333         v = devp->hd_irqdata;
 334         spin_unlock_irq(&hpet_lock);
 335
 336         if (v != 0)
 337                 return EPOLLIN | EPOLLRDNORM;
 338
 339         return 0;
 340 }
 341
 342 #ifdef CONFIG_HPET_MMAP
 343 #ifdef CONFIG_HPET_MMAP_DEFAULT
 344 static int hpet_mmap_enabled = 1;
 345 #else
 346 static int hpet_mmap_enabled = 0;
 347 #endif
 348
 349 static __init int hpet_mmap_enable(char *str)
 350 {
 351         get_option(&str, &hpet_mmap_enabled);
 352         pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
 353         return 1;
 354 }
 355 __setup("hpet_mmap=", hpet_mmap_enable);
 356
 357 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 358 {
 359         struct hpet_dev *devp;
 360         unsigned long addr;
 361
 362         if (!hpet_mmap_enabled)
 363                 return -EACCES;
 364
 365         devp = file->private_data;
 366         addr = devp->hd_hpets->hp_hpet_phys;
 367
 368         if (addr & (PAGE_SIZE - 1))
 369                 return -ENOSYS;
 370
 371         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 372         return vm_iomap_memory(vma, addr, PAGE_SIZE);
 373 }
 374 #else
 375 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 376 {
 377         return -ENOSYS;
 378 }
 379 #endif
 380
 381 static int hpet_fasync(int fd, struct file *file, int on)
 382 {
 383         struct hpet_dev *devp;
 384
 385         devp = file->private_data;
 386
 387         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 388                 return 0;
 389         else
 390                 return -EIO;
 391 }
 392
 393 static int hpet_release(struct inode *inode, struct file *file)
 394 {
 395         struct hpet_dev *devp;
 396         struct hpet_timer __iomem *timer;
 397         int irq = 0;
 398
 399         devp = file->private_data;
 400         timer = devp->hd_timer;
 401
 402         spin_lock_irq(&hpet_lock);
 403
 404         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 405                &timer->hpet_config);
 406
 407         irq = devp->hd_irq;
 408         devp->hd_irq = 0;
 409
 410         devp->hd_ireqfreq = 0;
 411
 412         if (devp->hd_flags & HPET_PERIODIC
 413             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 414                 unsigned long v;
 415
 416                 v = readq(&timer->hpet_config);
 417                 v ^= Tn_TYPE_CNF_MASK;
 418                 writeq(v, &timer->hpet_config);
 419         }
 420
 421         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 422         spin_unlock_irq(&hpet_lock);
 423
 424         if (irq)
 425                 free_irq(irq, devp);
 426
 427         file->private_data = NULL;
 428         return 0;
 429 }
 430
 431 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 432 {
 433         struct hpet_timer __iomem *timer;
 434         struct hpet __iomem *hpet;
 435         struct hpets *hpetp;
 436         int irq;
 437         unsigned long g, v, t, m;
 438         unsigned long flags, isr;
 439
 440         timer = devp->hd_timer;
 441         hpet = devp->hd_hpet;
 442         hpetp = devp->hd_hpets;
 443
 444         if (!devp->hd_ireqfreq)
 445                 return -EIO;
 446
 447         spin_lock_irq(&hpet_lock);
 448
 449         if (devp->hd_flags & HPET_IE) {
 450                 spin_unlock_irq(&hpet_lock);
 451                 return -EBUSY;
 452         }
 453
 454         devp->hd_flags |= HPET_IE;
 455
 456         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 457                 devp->hd_flags |= HPET_SHARED_IRQ;
 458         spin_unlock_irq(&hpet_lock);
 459
 460         irq = devp->hd_hdwirq;
 461
 462         if (irq) {
 463                 unsigned long irq_flags;
 464
 465                 if (devp->hd_flags & HPET_SHARED_IRQ) {
 466                         /*
 467                          * To prevent the interrupt handler from seeing an
 468                          * unwanted interrupt status bit, program the timer
 469                          * so that it will not fire in the near future ...
 470                          */
 471                         writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
 472                                &timer->hpet_config);
 473                         write_counter(read_counter(&hpet->hpet_mc),
 474                                       &timer->hpet_compare);
 475                         /* ... and clear any left-over status. */
 476                         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 477                         writel(isr, &hpet->hpet_isr);
 478                 }
 479
 480                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 481                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
 482                 if (request_irq(irq, hpet_interrupt, irq_flags,
 483                                 devp->hd_name, (void *)devp)) {
 484                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 485                         irq = 0;
 486                 }
 487         }
 488
 489         if (irq == 0) {
 490                 spin_lock_irq(&hpet_lock);
 491                 devp->hd_flags ^= HPET_IE;
 492                 spin_unlock_irq(&hpet_lock);
 493                 return -EIO;
 494         }
 495
 496         devp->hd_irq = irq;
 497         t = devp->hd_ireqfreq;
 498         v = readq(&timer->hpet_config);
 499
 500         /* 64-bit comparators are not yet supported through the ioctls,
 501          * so force this into 32-bit mode if it supports both modes
 502          */
 503         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 504
 505         if (devp->hd_flags & HPET_PERIODIC) {
 506                 g |= Tn_TYPE_CNF_MASK;
 507                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 508                 writeq(v, &timer->hpet_config);
 509                 local_irq_save(flags);
 510
 511                 /*
 512                  * NOTE: First we modify the hidden accumulator
 513                  * register supported by periodic-capable comparators.
 514                  * We never want to modify the (single) counter; that
 515                  * would affect all the comparators. The value written
 516                  * is the counter value when the first interrupt is due.
 517                  */
 518                 m = read_counter(&hpet->hpet_mc);
 519                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 520                 /*
 521                  * Then we modify the comparator, indicating the period
 522                  * for subsequent interrupt.
 523                  */
 524                 write_counter(t, &timer->hpet_compare);
 525         } else {
 526                 local_irq_save(flags);
 527                 m = read_counter(&hpet->hpet_mc);
 528                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 529         }
 530
 531         if (devp->hd_flags & HPET_SHARED_IRQ) {
 532                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 533                 writel(isr, &hpet->hpet_isr);
 534         }
 535         writeq(g, &timer->hpet_config);
 536         local_irq_restore(flags);
 537
 538         return 0;
 539 }
 540
 541 /* converts Hz to number of timer ticks */
 542 static inline unsigned long hpet_time_div(struct hpets *hpets,
 543                                           unsigned long dis)
 544 {
 545         unsigned long long m;
 546
 547         m = hpets->hp_tick_freq + (dis >> 1);
 548         return div64_ul(m, dis);
 549 }
 550
 551 static int
 552 hpet_ioctl_common(struct hpet_dev *devp, unsigned int cmd, unsigned long arg,
 553                   struct hpet_info *info)
 554 {
 555         struct hpet_timer __iomem *timer;
 556         struct hpets *hpetp;
 557         int err;
 558         unsigned long v;
 559
 560         switch (cmd) {
 561         case HPET_IE_OFF:
 562         case HPET_INFO:
 563         case HPET_EPI:
 564         case HPET_DPI:
 565         case HPET_IRQFREQ:
 566                 timer = devp->hd_timer;
 567                 hpetp = devp->hd_hpets;
 568                 break;
 569         case HPET_IE_ON:
 570                 return hpet_ioctl_ieon(devp);
 571         default:
 572                 return -EINVAL;
 573         }
 574
 575         err = 0;
 576
 577         switch (cmd) {
 578         case HPET_IE_OFF:
 579                 if ((devp->hd_flags & HPET_IE) == 0)
 580                         break;
 581                 v = readq(&timer->hpet_config);
 582                 v &= ~Tn_INT_ENB_CNF_MASK;
 583                 writeq(v, &timer->hpet_config);
 584                 if (devp->hd_irq) {
 585                         free_irq(devp->hd_irq, devp);
 586                         devp->hd_irq = 0;
 587                 }
 588                 devp->hd_flags ^= HPET_IE;
 589                 break;
 590         case HPET_INFO:
 591                 {
 592                         memset(info, 0, sizeof(*info));
 593                         if (devp->hd_ireqfreq)
 594                                 info->hi_ireqfreq =
 595                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 596                         info->hi_flags =
 597                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 598                         info->hi_hpet = hpetp->hp_which;
 599                         info->hi_timer = devp - hpetp->hp_dev;
 600                         break;
 601                 }
 602         case HPET_EPI:
 603                 v = readq(&timer->hpet_config);
 604                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 605                         err = -ENXIO;
 606                         break;
 607                 }
 608                 devp->hd_flags |= HPET_PERIODIC;
 609                 break;
 610         case HPET_DPI:
 611                 v = readq(&timer->hpet_config);
 612                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 613                         err = -ENXIO;
 614                         break;
 615                 }
 616                 if (devp->hd_flags & HPET_PERIODIC &&
 617                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 618                         v = readq(&timer->hpet_config);
 619                         v ^= Tn_TYPE_CNF_MASK;
 620                         writeq(v, &timer->hpet_config);
 621                 }
 622                 devp->hd_flags &= ~HPET_PERIODIC;
 623                 break;
 624         case HPET_IRQFREQ:
 625                 if ((arg > hpet_max_freq) &&
 626                     !capable(CAP_SYS_RESOURCE)) {
 627                         err = -EACCES;
 628                         break;
 629                 }
 630
 631                 if (!arg) {
 632                         err = -EINVAL;
 633                         break;
 634                 }
 635
 636                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 637         }
 638
 639         return err;
 640 }
 641
 642 static long
 643 hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 644 {
 645         struct hpet_info info;
 646         int err;
 647
 648         mutex_lock(&hpet_mutex);
 649         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 650         mutex_unlock(&hpet_mutex);
 651
 652         if ((cmd == HPET_INFO) && !err &&
 653             (copy_to_user((void __user *)arg, &info, sizeof(info))))
 654                 err = -EFAULT;
 655
 656         return err;
 657 }
 658
 659 #ifdef CONFIG_COMPAT
 660 struct compat_hpet_info {
 661         compat_ulong_t hi_ireqfreq;     /* Hz */
 662         compat_ulong_t hi_flags;        /* information */
 663         unsigned short hi_hpet;
 664         unsigned short hi_timer;
 665 };
 666
 667 /* 32-bit types would lead to different command codes which should be
 668  * translated into 64-bit ones before passed to hpet_ioctl_common
 669  */
 670 #define COMPAT_HPET_INFO       _IOR('h', 0x03, struct compat_hpet_info)
 671 #define COMPAT_HPET_IRQFREQ    _IOW('h', 0x6, compat_ulong_t)
 672
 673 static long
 674 hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 675 {
 676         struct hpet_info info;
 677         int err;
 678
 679         if (cmd == COMPAT_HPET_INFO)
 680                 cmd = HPET_INFO;
 681
 682         if (cmd == COMPAT_HPET_IRQFREQ)
 683                 cmd = HPET_IRQFREQ;
 684
 685         mutex_lock(&hpet_mutex);
 686         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 687         mutex_unlock(&hpet_mutex);
 688
 689         if ((cmd == HPET_INFO) && !err) {
 690                 struct compat_hpet_info __user *u = compat_ptr(arg);
 691                 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
 692                     put_user(info.hi_flags, &u->hi_flags) ||
 693                     put_user(info.hi_hpet, &u->hi_hpet) ||
 694                     put_user(info.hi_timer, &u->hi_timer))
 695                         err = -EFAULT;
 696         }
 697
 698         return err;
 699 }
 700 #endif
 701
 702 static const struct file_operations hpet_fops = {
 703         .owner = THIS_MODULE,
 704         .read = hpet_read,
 705         .poll = hpet_poll,
 706         .unlocked_ioctl = hpet_ioctl,
 707 #ifdef CONFIG_COMPAT
 708         .compat_ioctl = hpet_compat_ioctl,
 709 #endif
 710         .open = hpet_open,
 711         .release = hpet_release,
 712         .fasync = hpet_fasync,
 713         .mmap = hpet_mmap,
 714 };
 715
 716 static int hpet_is_known(struct hpet_data *hdp)
 717 {
 718         struct hpets *hpetp;
 719
 720         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 721                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 722                         return 1;
 723
 724         return 0;
 725 }
 726
 727 static struct ctl_table hpet_table[] = {
 728         {
 729          .procname = "max-user-freq",
 730          .data = &hpet_max_freq,
 731          .maxlen = sizeof(int),
 732          .mode = 0644,
 733          .proc_handler = proc_dointvec,
 734          },
 735 };
 736
 737 static struct ctl_table_header *sysctl_header;
 738
 739 /*
 740  * Adjustment for when arming the timer with
 741  * initial conditions.  That is, main counter
 742  * ticks expired before interrupts are enabled.
 743  */
 744 #define TICK_CALIBRATE  (1000UL)
 745
 746 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 747 {
 748         struct hpet_timer __iomem *timer = NULL;
 749         unsigned long t, m, count, i, flags, start;
 750         struct hpet_dev *devp;
 751         int j;
 752         struct hpet __iomem *hpet;
 753
 754         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 755                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 756                         timer = devp->hd_timer;
 757                         break;
 758                 }
 759
 760         if (!timer)
 761                 return 0;
 762
 763         hpet = hpetp->hp_hpet;
 764         t = read_counter(&timer->hpet_compare);
 765
 766         i = 0;
 767         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 768
 769         local_irq_save(flags);
 770
 771         start = read_counter(&hpet->hpet_mc);
 772
 773         do {
 774                 m = read_counter(&hpet->hpet_mc);
 775                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 776         } while (i++, (m - start) < count);
 777
 778         local_irq_restore(flags);
 779
 780         return (m - start) / i;
 781 }
 782
 783 static unsigned long hpet_calibrate(struct hpets *hpetp)
 784 {
 785         unsigned long ret = ~0UL;
 786         unsigned long tmp;
 787
 788         /*
 789          * Try to calibrate until return value becomes stable small value.
 790          * If SMI interruption occurs in calibration loop, the return value
 791          * will be big. This avoids its impact.
 792          */
 793         for ( ; ; ) {
 794                 tmp = __hpet_calibrate(hpetp);
 795                 if (ret <= tmp)
 796                         break;
 797                 ret = tmp;
 798         }
 799
 800         return ret;
 801 }
 802
 803 int hpet_alloc(struct hpet_data *hdp)
 804 {
 805         u64 cap, mcfg;
 806         struct hpet_dev *devp;
 807         u32 i, ntimer;
 808         struct hpets *hpetp;
 809         struct hpet __iomem *hpet;
 810         static struct hpets *last;
 811         u32 period;
 812         unsigned long long temp;
 813         u32 remainder;
 814
 815         /*
 816          * hpet_alloc can be called by platform dependent code.
 817          * If platform dependent code has allocated the hpet that
 818          * ACPI has also reported, then we catch it here.
 819          */
 820         if (hpet_is_known(hdp)) {
 821                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 822                         __func__);
 823                 return 0;
 824         }
 825
 826         hpetp = kzalloc(struct_size(hpetp, hp_dev, hdp->hd_nirqs),
 827                         GFP_KERNEL);
 828
 829         if (!hpetp)
 830                 return -ENOMEM;
 831
 832         hpetp->hp_which = hpet_nhpet++;
 833         hpetp->hp_hpet = hdp->hd_address;
 834         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 835
 836         hpetp->hp_ntimer = hdp->hd_nirqs;
 837
 838         for (i = 0; i < hdp->hd_nirqs; i++)
 839                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 840
 841         hpet = hpetp->hp_hpet;
 842
 843         cap = readq(&hpet->hpet_cap);
 844
 845         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 846
 847         if (hpetp->hp_ntimer != ntimer) {
 848                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 849                        " with number of timers\n");
 850                 kfree(hpetp);
 851                 return -ENODEV;
 852         }
 853
 854         if (last)
 855                 last->hp_next = hpetp;
 856         else
 857                 hpets = hpetp;
 858
 859         last = hpetp;
 860
 861         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 862                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 863         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 864         temp += period >> 1; /* round */
 865         do_div(temp, period);
 866         hpetp->hp_tick_freq = temp; /* ticks per second */
 867
 868         printk(KERN_INFO "hpet%u: at MMIO 0x%lx, IRQ%s",
 869                 hpetp->hp_which, hdp->hd_phys_address,
 870                 hpetp->hp_ntimer > 1 ? "s" : "");
 871         for (i = 0; i < hpetp->hp_ntimer; i++)
 872                 printk(KERN_CONT "%s %u", i > 0 ? "," : "", hdp->hd_irq[i]);
 873         printk(KERN_CONT "\n");
 874
 875         temp = hpetp->hp_tick_freq;
 876         remainder = do_div(temp, 1000000);
 877         printk(KERN_INFO
 878                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 879                 hpetp->hp_which, hpetp->hp_ntimer,
 880                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 881                 (unsigned) temp, remainder);
 882
 883         mcfg = readq(&hpet->hpet_config);
 884         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 885                 write_counter(0L, &hpet->hpet_mc);
 886                 mcfg |= HPET_ENABLE_CNF_MASK;
 887                 writeq(mcfg, &hpet->hpet_config);
 888         }
 889
 890         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 891                 struct hpet_timer __iomem *timer;
 892
 893                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 894
 895                 devp->hd_hpets = hpetp;
 896                 devp->hd_hpet = hpet;
 897                 devp->hd_timer = timer;
 898
 899                 /*
 900                  * If the timer was reserved by platform code,
 901                  * then make timer unavailable for opens.
 902                  */
 903                 if (hdp->hd_state & (1 << i)) {
 904                         devp->hd_flags = HPET_OPEN;
 905                         continue;
 906                 }
 907
 908                 init_waitqueue_head(&devp->hd_waitqueue);
 909         }
 910
 911         hpetp->hp_delta = hpet_calibrate(hpetp);
 912
 913         return 0;
 914 }
 915
 916 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 917 {
 918         struct hpet_data *hdp;
 919         acpi_status status;
 920         struct acpi_resource_address64 addr;
 921
 922         hdp = data;
 923
 924         status = acpi_resource_to_address64(res, &addr);
 925
 926         if (ACPI_SUCCESS(status)) {
 927                 hdp->hd_phys_address = addr.address.minimum;
 928                 hdp->hd_address = ioremap(addr.address.minimum, addr.address.address_length);
 929                 if (!hdp->hd_address)
 930                         return AE_ERROR;
 931
 932                 if (hpet_is_known(hdp)) {
 933                         iounmap(hdp->hd_address);
 934                         return AE_ALREADY_EXISTS;
 935                 }
 936         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 937                 struct acpi_resource_fixed_memory32 *fixmem32;
 938
 939                 fixmem32 = &res->data.fixed_memory32;
 940
 941                 hdp->hd_phys_address = fixmem32->address;
 942                 hdp->hd_address = ioremap(fixmem32->address,
 943                                                 HPET_RANGE_SIZE);
 944                 if (!hdp->hd_address)
 945                         return AE_ERROR;
 946
 947                 if (hpet_is_known(hdp)) {
 948                         iounmap(hdp->hd_address);
 949                         return AE_ALREADY_EXISTS;
 950                 }
 951         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 952                 struct acpi_resource_extended_irq *irqp;
 953                 int i, irq;
 954
 955                 irqp = &res->data.extended_irq;
 956
 957                 for (i = 0; i < irqp->interrupt_count; i++) {
 958                         if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
 959                                 break;
 960
 961                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
 962                                                 irqp->triggering,
 963                                                 irqp->polarity);
 964                         if (irq < 0)
 965                                 return AE_ERROR;
 966
 967                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 968                         hdp->hd_nirqs++;
 969                 }
 970         }
 971
 972         return AE_OK;
 973 }
 974
 975 static int hpet_acpi_add(struct acpi_device *device)
 976 {
 977         acpi_status result;
 978         struct hpet_data data;
 979
 980         memset(&data, 0, sizeof(data));
 981
 982         result =
 983             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 984                                 hpet_resources, &data);
 985
 986         if (ACPI_FAILURE(result))
 987                 return -ENODEV;
 988
 989         if (!data.hd_address || !data.hd_nirqs) {
 990                 if (data.hd_address)
 991                         iounmap(data.hd_address);
 992                 printk("%s: no address or irqs in _CRS\n", __func__);
 993                 return -ENODEV;
 994         }
 995
 996         return hpet_alloc(&data);
 997 }
 998
 999 static const struct acpi_device_id hpet_device_ids[] = {
1000         {"PNP0103", 0},
1001         {"", 0},
1002 };
1003
1004 static struct acpi_driver hpet_acpi_driver = {
1005         .name = "hpet",
1006         .ids = hpet_device_ids,
1007         .ops = {
1008                 .add = hpet_acpi_add,
1009                 },
1010 };
1011
1012 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1013
1014 static int __init hpet_init(void)
1015 {
1016         int result;
1017
1018         result = misc_register(&hpet_misc);
1019         if (result < 0)
1020                 return -ENODEV;
1021
1022         sysctl_header = register_sysctl("dev/hpet", hpet_table);
1023
1024         result = acpi_bus_register_driver(&hpet_acpi_driver);
1025         if (result < 0) {
1026                 if (sysctl_header)
1027                         unregister_sysctl_table(sysctl_header);
1028                 misc_deregister(&hpet_misc);
1029                 return result;
1030         }
1031
1032         return 0;
1033 }
1034 device_initcall(hpet_init);
1035
1036 /*
1037 MODULE_AUTHOR("Bob Picco <[email protected]>");
1038 MODULE_LICENSE("GPL");
1039 */