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