drivers/char/hpet.c

   1 /*
   2  * Intel & MS High Precision Event Timer Implementation.
   3  *
   4  * Copyright (C) 2003 Intel Corporation
   5  *      Venki Pallipadi
   6  * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
   7  *      Bob Picco <robert.picco@hp.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/interrupt.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/types.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/major.h>
  20 #include <linux/ioport.h>
  21 #include <linux/fcntl.h>
  22 #include <linux/init.h>
  23 #include <linux/poll.h>
  24 #include <linux/mm.h>
  25 #include <linux/proc_fs.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/wait.h>
  29 #include <linux/bcd.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/bitops.h>
  32 #include <linux/compat.h>
  33 #include <linux/clocksource.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/slab.h>
  36 #include <linux/io.h>
  37
  38 #include <asm/current.h>
  39 #include <asm/system.h>
  40 #include <asm/irq.h>
  41 #include <asm/div64.h>
  42
  43 #include <linux/acpi.h>
  44 #include <acpi/acpi_bus.h>
  45 #include <linux/hpet.h>
  46
  47 /*
  48  * The High Precision Event Timer driver.
  49  * This driver is closely modelled after the rtc.c driver.
  50  * http://www.intel.com/hardwaredesign/hpetspec_1.pdf
  51  */
  52 #define HPET_USER_FREQ  (64)
  53 #define HPET_DRIFT      (500)
  54
  55 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
  56
  57
  58 /* WARNING -- don't get confused.  These macros are never used
  59  * to write the (single) counter, and rarely to read it.
  60  * They're badly named; to fix, someday.
  61  */
  62 #if BITS_PER_LONG == 64
  63 #define write_counter(V, MC)    writeq(V, MC)
  64 #define read_counter(MC)        readq(MC)
  65 #else
  66 #define write_counter(V, MC)    writel(V, MC)
  67 #define read_counter(MC)        readl(MC)
  68 #endif
  69
  70 static DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
  71 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  72
  73 /* This clocksource driver currently only works on ia64 */
  74 #ifdef CONFIG_IA64
  75 static void __iomem *hpet_mctr;
  76
  77 static cycle_t read_hpet(struct clocksource *cs)
  78 {
  79         return (cycle_t)read_counter((void __iomem *)hpet_mctr);
  80 }
  81
  82 static struct clocksource clocksource_hpet = {
  83         .name           = "hpet",
  84         .rating         = 250,
  85         .read           = read_hpet,
  86         .mask           = CLOCKSOURCE_MASK(64),
  87         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  88 };
  89 static struct clocksource *hpet_clocksource;
  90 #endif
  91
  92 /* A lock for concurrent access by app and isr hpet activity. */
  93 static DEFINE_SPINLOCK(hpet_lock);
  94
  95 #define HPET_DEV_NAME   (7)
  96
  97 struct hpet_dev {
  98         struct hpets *hd_hpets;
  99         struct hpet __iomem *hd_hpet;
 100         struct hpet_timer __iomem *hd_timer;
 101         unsigned long hd_ireqfreq;
 102         unsigned long hd_irqdata;
 103         wait_queue_head_t hd_waitqueue;
 104         struct fasync_struct *hd_async_queue;
 105         unsigned int hd_flags;
 106         unsigned int hd_irq;
 107         unsigned int hd_hdwirq;
 108         char hd_name[HPET_DEV_NAME];
 109 };
 110
 111 struct hpets {
 112         struct hpets *hp_next;
 113         struct hpet __iomem *hp_hpet;
 114         unsigned long hp_hpet_phys;
 115         struct clocksource *hp_clocksource;
 116         unsigned long long hp_tick_freq;
 117         unsigned long hp_delta;
 118         unsigned int hp_ntimer;
 119         unsigned int hp_which;
 120         struct hpet_dev hp_dev[1];
 121 };
 122
 123 static struct hpets *hpets;
 124
 125 #define HPET_OPEN               0x0001
 126 #define HPET_IE                 0x0002  /* interrupt enabled */
 127 #define HPET_PERIODIC           0x0004
 128 #define HPET_SHARED_IRQ         0x0008
 129
 130
 131 #ifndef readq
 132 static inline unsigned long long readq(void __iomem *addr)
 133 {
 134         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 135 }
 136 #endif
 137
 138 #ifndef writeq
 139 static inline void writeq(unsigned long long v, void __iomem *addr)
 140 {
 141         writel(v & 0xffffffff, addr);
 142         writel(v >> 32, addr + 4);
 143 }
 144 #endif
 145
 146 static irqreturn_t hpet_interrupt(int irq, void *data)
 147 {
 148         struct hpet_dev *devp;
 149         unsigned long isr;
 150
 151         devp = data;
 152         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 153
 154         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 155             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 156                 return IRQ_NONE;
 157
 158         spin_lock(&hpet_lock);
 159         devp->hd_irqdata++;
 160
 161         /*
 162          * For non-periodic timers, increment the accumulator.
 163          * This has the effect of treating non-periodic like periodic.
 164          */
 165         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 166                 unsigned long m, t, mc, base, k;
 167                 struct hpet __iomem *hpet = devp->hd_hpet;
 168                 struct hpets *hpetp = devp->hd_hpets;
 169
 170                 t = devp->hd_ireqfreq;
 171                 m = read_counter(&devp->hd_timer->hpet_compare);
 172                 mc = read_counter(&hpet->hpet_mc);
 173                 /* The time for the next interrupt would logically be t + m,
 174                  * however, if we are very unlucky and the interrupt is delayed
 175                  * for longer than t then we will completely miss the next
 176                  * interrupt if we set t + m and an application will hang.
 177                  * Therefore we need to make a more complex computation assuming
 178                  * that there exists a k for which the following is true:
 179                  * k * t + base < mc + delta
 180                  * (k + 1) * t + base > mc + delta
 181                  * where t is the interval in hpet ticks for the given freq,
 182                  * base is the theoretical start value 0 < base < t,
 183                  * mc is the main counter value at the time of the interrupt,
 184                  * delta is the time it takes to write the a value to the
 185                  * comparator.
 186                  * k may then be computed as (mc - base + delta) / t .
 187                  */
 188                 base = mc % t;
 189                 k = (mc - base + hpetp->hp_delta) / t;
 190                 write_counter(t * (k + 1) + base,
 191                               &devp->hd_timer->hpet_compare);
 192         }
 193
 194         if (devp->hd_flags & HPET_SHARED_IRQ)
 195                 writel(isr, &devp->hd_hpet->hpet_isr);
 196         spin_unlock(&hpet_lock);
 197
 198         wake_up_interruptible(&devp->hd_waitqueue);
 199
 200         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 201
 202         return IRQ_HANDLED;
 203 }
 204
 205 static void hpet_timer_set_irq(struct hpet_dev *devp)
 206 {
 207         unsigned long v;
 208         int irq, gsi;
 209         struct hpet_timer __iomem *timer;
 210
 211         spin_lock_irq(&hpet_lock);
 212         if (devp->hd_hdwirq) {
 213                 spin_unlock_irq(&hpet_lock);
 214                 return;
 215         }
 216
 217         timer = devp->hd_timer;
 218
 219         /* we prefer level triggered mode */
 220         v = readl(&timer->hpet_config);
 221         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
 222                 v |= Tn_INT_TYPE_CNF_MASK;
 223                 writel(v, &timer->hpet_config);
 224         }
 225         spin_unlock_irq(&hpet_lock);
 226
 227         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
 228                                  Tn_INT_ROUTE_CAP_SHIFT;
 229
 230         /*
 231          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
 232          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
 233          */
 234         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 235                 v &= ~0xf3df;
 236         else
 237                 v &= ~0xffff;
 238
 239         for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
 240                 if (irq >= nr_irqs) {
 241                         irq = HPET_MAX_IRQ;
 242                         break;
 243                 }
 244
 245                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
 246                                         ACPI_ACTIVE_LOW);
 247                 if (gsi > 0)
 248                         break;
 249
 250                 /* FIXME: Setup interrupt source table */
 251         }
 252
 253         if (irq < HPET_MAX_IRQ) {
 254                 spin_lock_irq(&hpet_lock);
 255                 v = readl(&timer->hpet_config);
 256                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 257                 writel(v, &timer->hpet_config);
 258                 devp->hd_hdwirq = gsi;
 259                 spin_unlock_irq(&hpet_lock);
 260         }
 261         return;
 262 }
 263
 264 static int hpet_open(struct inode *inode, struct file *file)
 265 {
 266         struct hpet_dev *devp;
 267         struct hpets *hpetp;
 268         int i;
 269
 270         if (file->f_mode & FMODE_WRITE)
 271                 return -EINVAL;
 272
 273         mutex_lock(&hpet_mutex);
 274         spin_lock_irq(&hpet_lock);
 275
 276         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 277                 for (i = 0; i < hpetp->hp_ntimer; i++)
 278                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
 279                                 continue;
 280                         else {
 281                                 devp = &hpetp->hp_dev[i];
 282                                 break;
 283                         }
 284
 285         if (!devp) {
 286                 spin_unlock_irq(&hpet_lock);
 287                 mutex_unlock(&hpet_mutex);
 288                 return -EBUSY;
 289         }
 290
 291         file->private_data = devp;
 292         devp->hd_irqdata = 0;
 293         devp->hd_flags |= HPET_OPEN;
 294         spin_unlock_irq(&hpet_lock);
 295         mutex_unlock(&hpet_mutex);
 296
 297         hpet_timer_set_irq(devp);
 298
 299         return 0;
 300 }
 301
 302 static ssize_t
 303 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 304 {
 305         DECLARE_WAITQUEUE(wait, current);
 306         unsigned long data;
 307         ssize_t retval;
 308         struct hpet_dev *devp;
 309
 310         devp = file->private_data;
 311         if (!devp->hd_ireqfreq)
 312                 return -EIO;
 313
 314         if (count < sizeof(unsigned long))
 315                 return -EINVAL;
 316
 317         add_wait_queue(&devp->hd_waitqueue, &wait);
 318
 319         for ( ; ; ) {
 320                 set_current_state(TASK_INTERRUPTIBLE);
 321
 322                 spin_lock_irq(&hpet_lock);
 323                 data = devp->hd_irqdata;
 324                 devp->hd_irqdata = 0;
 325                 spin_unlock_irq(&hpet_lock);
 326
 327                 if (data)
 328                         break;
 329                 else if (file->f_flags & O_NONBLOCK) {
 330                         retval = -EAGAIN;
 331                         goto out;
 332                 } else if (signal_pending(current)) {
 333                         retval = -ERESTARTSYS;
 334                         goto out;
 335                 }
 336                 schedule();
 337         }
 338
 339         retval = put_user(data, (unsigned long __user *)buf);
 340         if (!retval)
 341                 retval = sizeof(unsigned long);
 342 out:
 343         __set_current_state(TASK_RUNNING);
 344         remove_wait_queue(&devp->hd_waitqueue, &wait);
 345
 346         return retval;
 347 }
 348
 349 static unsigned int hpet_poll(struct file *file, poll_table * wait)
 350 {
 351         unsigned long v;
 352         struct hpet_dev *devp;
 353
 354         devp = file->private_data;
 355
 356         if (!devp->hd_ireqfreq)
 357                 return 0;
 358
 359         poll_wait(file, &devp->hd_waitqueue, wait);
 360
 361         spin_lock_irq(&hpet_lock);
 362         v = devp->hd_irqdata;
 363         spin_unlock_irq(&hpet_lock);
 364
 365         if (v != 0)
 366                 return POLLIN | POLLRDNORM;
 367
 368         return 0;
 369 }
 370
 371 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 372 {
 373 #ifdef  CONFIG_HPET_MMAP
 374         struct hpet_dev *devp;
 375         unsigned long addr;
 376
 377         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
 378                 return -EINVAL;
 379
 380         devp = file->private_data;
 381         addr = devp->hd_hpets->hp_hpet_phys;
 382
 383         if (addr & (PAGE_SIZE - 1))
 384                 return -ENOSYS;
 385
 386         vma->vm_flags |= VM_IO;
 387         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 388
 389         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
 390                                         PAGE_SIZE, vma->vm_page_prot)) {
 391                 printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
 392                         __func__);
 393                 return -EAGAIN;
 394         }
 395
 396         return 0;
 397 #else
 398         return -ENOSYS;
 399 #endif
 400 }
 401
 402 static int hpet_fasync(int fd, struct file *file, int on)
 403 {
 404         struct hpet_dev *devp;
 405
 406         devp = file->private_data;
 407
 408         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 409                 return 0;
 410         else
 411                 return -EIO;
 412 }
 413
 414 static int hpet_release(struct inode *inode, struct file *file)
 415 {
 416         struct hpet_dev *devp;
 417         struct hpet_timer __iomem *timer;
 418         int irq = 0;
 419
 420         devp = file->private_data;
 421         timer = devp->hd_timer;
 422
 423         spin_lock_irq(&hpet_lock);
 424
 425         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 426                &timer->hpet_config);
 427
 428         irq = devp->hd_irq;
 429         devp->hd_irq = 0;
 430
 431         devp->hd_ireqfreq = 0;
 432
 433         if (devp->hd_flags & HPET_PERIODIC
 434             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 435                 unsigned long v;
 436
 437                 v = readq(&timer->hpet_config);
 438                 v ^= Tn_TYPE_CNF_MASK;
 439                 writeq(v, &timer->hpet_config);
 440         }
 441
 442         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 443         spin_unlock_irq(&hpet_lock);
 444
 445         if (irq)
 446                 free_irq(irq, devp);
 447
 448         file->private_data = NULL;
 449         return 0;
 450 }
 451
 452 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 453 {
 454         struct hpet_timer __iomem *timer;
 455         struct hpet __iomem *hpet;
 456         struct hpets *hpetp;
 457         int irq;
 458         unsigned long g, v, t, m;
 459         unsigned long flags, isr;
 460
 461         timer = devp->hd_timer;
 462         hpet = devp->hd_hpet;
 463         hpetp = devp->hd_hpets;
 464
 465         if (!devp->hd_ireqfreq)
 466                 return -EIO;
 467
 468         spin_lock_irq(&hpet_lock);
 469
 470         if (devp->hd_flags & HPET_IE) {
 471                 spin_unlock_irq(&hpet_lock);
 472                 return -EBUSY;
 473         }
 474
 475         devp->hd_flags |= HPET_IE;
 476
 477         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 478                 devp->hd_flags |= HPET_SHARED_IRQ;
 479         spin_unlock_irq(&hpet_lock);
 480
 481         irq = devp->hd_hdwirq;
 482
 483         if (irq) {
 484                 unsigned long irq_flags;
 485
 486                 if (devp->hd_flags & HPET_SHARED_IRQ) {
 487                         /*
 488                          * To prevent the interrupt handler from seeing an
 489                          * unwanted interrupt status bit, program the timer
 490                          * so that it will not fire in the near future ...
 491                          */
 492                         writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
 493                                &timer->hpet_config);
 494                         write_counter(read_counter(&hpet->hpet_mc),
 495                                       &timer->hpet_compare);
 496                         /* ... and clear any left-over status. */
 497                         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 498                         writel(isr, &hpet->hpet_isr);
 499                 }
 500
 501                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 502                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 503                                                 ? IRQF_SHARED : IRQF_DISABLED;
 504                 if (request_irq(irq, hpet_interrupt, irq_flags,
 505                                 devp->hd_name, (void *)devp)) {
 506                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 507                         irq = 0;
 508                 }
 509         }
 510
 511         if (irq == 0) {
 512                 spin_lock_irq(&hpet_lock);
 513                 devp->hd_flags ^= HPET_IE;
 514                 spin_unlock_irq(&hpet_lock);
 515                 return -EIO;
 516         }
 517
 518         devp->hd_irq = irq;
 519         t = devp->hd_ireqfreq;
 520         v = readq(&timer->hpet_config);
 521
 522         /* 64-bit comparators are not yet supported through the ioctls,
 523          * so force this into 32-bit mode if it supports both modes
 524          */
 525         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 526
 527         if (devp->hd_flags & HPET_PERIODIC) {
 528                 g |= Tn_TYPE_CNF_MASK;
 529                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 530                 writeq(v, &timer->hpet_config);
 531                 local_irq_save(flags);
 532
 533                 /*
 534                  * NOTE: First we modify the hidden accumulator
 535                  * register supported by periodic-capable comparators.
 536                  * We never want to modify the (single) counter; that
 537                  * would affect all the comparators. The value written
 538                  * is the counter value when the first interrupt is due.
 539                  */
 540                 m = read_counter(&hpet->hpet_mc);
 541                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 542                 /*
 543                  * Then we modify the comparator, indicating the period
 544                  * for subsequent interrupt.
 545                  */
 546                 write_counter(t, &timer->hpet_compare);
 547         } else {
 548                 local_irq_save(flags);
 549                 m = read_counter(&hpet->hpet_mc);
 550                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 551         }
 552
 553         if (devp->hd_flags & HPET_SHARED_IRQ) {
 554                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 555                 writel(isr, &hpet->hpet_isr);
 556         }
 557         writeq(g, &timer->hpet_config);
 558         local_irq_restore(flags);
 559
 560         return 0;
 561 }
 562
 563 /* converts Hz to number of timer ticks */
 564 static inline unsigned long hpet_time_div(struct hpets *hpets,
 565                                           unsigned long dis)
 566 {
 567         unsigned long long m;
 568
 569         m = hpets->hp_tick_freq + (dis >> 1);
 570         do_div(m, dis);
 571         return (unsigned long)m;
 572 }
 573
 574 static int
 575 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg,
 576                   struct hpet_info *info)
 577 {
 578         struct hpet_timer __iomem *timer;
 579         struct hpet __iomem *hpet;
 580         struct hpets *hpetp;
 581         int err;
 582         unsigned long v;
 583
 584         switch (cmd) {
 585         case HPET_IE_OFF:
 586         case HPET_INFO:
 587         case HPET_EPI:
 588         case HPET_DPI:
 589         case HPET_IRQFREQ:
 590                 timer = devp->hd_timer;
 591                 hpet = devp->hd_hpet;
 592                 hpetp = devp->hd_hpets;
 593                 break;
 594         case HPET_IE_ON:
 595                 return hpet_ioctl_ieon(devp);
 596         default:
 597                 return -EINVAL;
 598         }
 599
 600         err = 0;
 601
 602         switch (cmd) {
 603         case HPET_IE_OFF:
 604                 if ((devp->hd_flags & HPET_IE) == 0)
 605                         break;
 606                 v = readq(&timer->hpet_config);
 607                 v &= ~Tn_INT_ENB_CNF_MASK;
 608                 writeq(v, &timer->hpet_config);
 609                 if (devp->hd_irq) {
 610                         free_irq(devp->hd_irq, devp);
 611                         devp->hd_irq = 0;
 612                 }
 613                 devp->hd_flags ^= HPET_IE;
 614                 break;
 615         case HPET_INFO:
 616                 {
 617                         memset(info, 0, sizeof(*info));
 618                         if (devp->hd_ireqfreq)
 619                                 info->hi_ireqfreq =
 620                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 621                         info->hi_flags =
 622                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 623                         info->hi_hpet = hpetp->hp_which;
 624                         info->hi_timer = devp - hpetp->hp_dev;
 625                         break;
 626                 }
 627         case HPET_EPI:
 628                 v = readq(&timer->hpet_config);
 629                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 630                         err = -ENXIO;
 631                         break;
 632                 }
 633                 devp->hd_flags |= HPET_PERIODIC;
 634                 break;
 635         case HPET_DPI:
 636                 v = readq(&timer->hpet_config);
 637                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 638                         err = -ENXIO;
 639                         break;
 640                 }
 641                 if (devp->hd_flags & HPET_PERIODIC &&
 642                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 643                         v = readq(&timer->hpet_config);
 644                         v ^= Tn_TYPE_CNF_MASK;
 645                         writeq(v, &timer->hpet_config);
 646                 }
 647                 devp->hd_flags &= ~HPET_PERIODIC;
 648                 break;
 649         case HPET_IRQFREQ:
 650                 if ((arg > hpet_max_freq) &&
 651                     !capable(CAP_SYS_RESOURCE)) {
 652                         err = -EACCES;
 653                         break;
 654                 }
 655
 656                 if (!arg) {
 657                         err = -EINVAL;
 658                         break;
 659                 }
 660
 661                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 662         }
 663
 664         return err;
 665 }
 666
 667 static long
 668 hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 669 {
 670         struct hpet_info info;
 671         int err;
 672
 673         mutex_lock(&hpet_mutex);
 674         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 675         mutex_unlock(&hpet_mutex);
 676
 677         if ((cmd == HPET_INFO) && !err &&
 678             (copy_to_user((void __user *)arg, &info, sizeof(info))))
 679                 err = -EFAULT;
 680
 681         return err;
 682 }
 683
 684 #ifdef CONFIG_COMPAT
 685 struct compat_hpet_info {
 686         compat_ulong_t hi_ireqfreq;     /* Hz */
 687         compat_ulong_t hi_flags;        /* information */
 688         unsigned short hi_hpet;
 689         unsigned short hi_timer;
 690 };
 691
 692 static long
 693 hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 694 {
 695         struct hpet_info info;
 696         int err;
 697
 698         mutex_lock(&hpet_mutex);
 699         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 700         mutex_unlock(&hpet_mutex);
 701
 702         if ((cmd == HPET_INFO) && !err) {
 703                 struct compat_hpet_info __user *u = compat_ptr(arg);
 704                 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
 705                     put_user(info.hi_flags, &u->hi_flags) ||
 706                     put_user(info.hi_hpet, &u->hi_hpet) ||
 707                     put_user(info.hi_timer, &u->hi_timer))
 708                         err = -EFAULT;
 709         }
 710
 711         return err;
 712 }
 713 #endif
 714
 715 static const struct file_operations hpet_fops = {
 716         .owner = THIS_MODULE,
 717         .llseek = no_llseek,
 718         .read = hpet_read,
 719         .poll = hpet_poll,
 720         .unlocked_ioctl = hpet_ioctl,
 721 #ifdef CONFIG_COMPAT
 722         .compat_ioctl = hpet_compat_ioctl,
 723 #endif
 724         .open = hpet_open,
 725         .release = hpet_release,
 726         .fasync = hpet_fasync,
 727         .mmap = hpet_mmap,
 728 };
 729
 730 static int hpet_is_known(struct hpet_data *hdp)
 731 {
 732         struct hpets *hpetp;
 733
 734         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 735                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 736                         return 1;
 737
 738         return 0;
 739 }
 740
 741 static ctl_table hpet_table[] = {
 742         {
 743          .procname = "max-user-freq",
 744          .data = &hpet_max_freq,
 745          .maxlen = sizeof(int),
 746          .mode = 0644,
 747          .proc_handler = proc_dointvec,
 748          },
 749         {}
 750 };
 751
 752 static ctl_table hpet_root[] = {
 753         {
 754          .procname = "hpet",
 755          .maxlen = 0,
 756          .mode = 0555,
 757          .child = hpet_table,
 758          },
 759         {}
 760 };
 761
 762 static ctl_table dev_root[] = {
 763         {
 764          .procname = "dev",
 765          .maxlen = 0,
 766          .mode = 0555,
 767          .child = hpet_root,
 768          },
 769         {}
 770 };
 771
 772 static struct ctl_table_header *sysctl_header;
 773
 774 /*
 775  * Adjustment for when arming the timer with
 776  * initial conditions.  That is, main counter
 777  * ticks expired before interrupts are enabled.
 778  */
 779 #define TICK_CALIBRATE  (1000UL)
 780
 781 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 782 {
 783         struct hpet_timer __iomem *timer = NULL;
 784         unsigned long t, m, count, i, flags, start;
 785         struct hpet_dev *devp;
 786         int j;
 787         struct hpet __iomem *hpet;
 788
 789         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 790                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 791                         timer = devp->hd_timer;
 792                         break;
 793                 }
 794
 795         if (!timer)
 796                 return 0;
 797
 798         hpet = hpetp->hp_hpet;
 799         t = read_counter(&timer->hpet_compare);
 800
 801         i = 0;
 802         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 803
 804         local_irq_save(flags);
 805
 806         start = read_counter(&hpet->hpet_mc);
 807
 808         do {
 809                 m = read_counter(&hpet->hpet_mc);
 810                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 811         } while (i++, (m - start) < count);
 812
 813         local_irq_restore(flags);
 814
 815         return (m - start) / i;
 816 }
 817
 818 static unsigned long hpet_calibrate(struct hpets *hpetp)
 819 {
 820         unsigned long ret = -1;
 821         unsigned long tmp;
 822
 823         /*
 824          * Try to calibrate until return value becomes stable small value.
 825          * If SMI interruption occurs in calibration loop, the return value
 826          * will be big. This avoids its impact.
 827          */
 828         for ( ; ; ) {
 829                 tmp = __hpet_calibrate(hpetp);
 830                 if (ret <= tmp)
 831                         break;
 832                 ret = tmp;
 833         }
 834
 835         return ret;
 836 }
 837
 838 int hpet_alloc(struct hpet_data *hdp)
 839 {
 840         u64 cap, mcfg;
 841         struct hpet_dev *devp;
 842         u32 i, ntimer;
 843         struct hpets *hpetp;
 844         size_t siz;
 845         struct hpet __iomem *hpet;
 846         static struct hpets *last;
 847         unsigned long period;
 848         unsigned long long temp;
 849         u32 remainder;
 850
 851         /*
 852          * hpet_alloc can be called by platform dependent code.
 853          * If platform dependent code has allocated the hpet that
 854          * ACPI has also reported, then we catch it here.
 855          */
 856         if (hpet_is_known(hdp)) {
 857                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 858                         __func__);
 859                 return 0;
 860         }
 861
 862         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 863                                       sizeof(struct hpet_dev));
 864
 865         hpetp = kzalloc(siz, GFP_KERNEL);
 866
 867         if (!hpetp)
 868                 return -ENOMEM;
 869
 870         hpetp->hp_which = hpet_nhpet++;
 871         hpetp->hp_hpet = hdp->hd_address;
 872         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 873
 874         hpetp->hp_ntimer = hdp->hd_nirqs;
 875
 876         for (i = 0; i < hdp->hd_nirqs; i++)
 877                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 878
 879         hpet = hpetp->hp_hpet;
 880
 881         cap = readq(&hpet->hpet_cap);
 882
 883         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 884
 885         if (hpetp->hp_ntimer != ntimer) {
 886                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 887                        " with number of timers\n");
 888                 kfree(hpetp);
 889                 return -ENODEV;
 890         }
 891
 892         if (last)
 893                 last->hp_next = hpetp;
 894         else
 895                 hpets = hpetp;
 896
 897         last = hpetp;
 898
 899         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 900                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 901         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 902         temp += period >> 1; /* round */
 903         do_div(temp, period);
 904         hpetp->hp_tick_freq = temp; /* ticks per second */
 905
 906         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 907                 hpetp->hp_which, hdp->hd_phys_address,
 908                 hpetp->hp_ntimer > 1 ? "s" : "");
 909         for (i = 0; i < hpetp->hp_ntimer; i++)
 910                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 911         printk("\n");
 912
 913         temp = hpetp->hp_tick_freq;
 914         remainder = do_div(temp, 1000000);
 915         printk(KERN_INFO
 916                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 917                 hpetp->hp_which, hpetp->hp_ntimer,
 918                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 919                 (unsigned) temp, remainder);
 920
 921         mcfg = readq(&hpet->hpet_config);
 922         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 923                 write_counter(0L, &hpet->hpet_mc);
 924                 mcfg |= HPET_ENABLE_CNF_MASK;
 925                 writeq(mcfg, &hpet->hpet_config);
 926         }
 927
 928         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 929                 struct hpet_timer __iomem *timer;
 930
 931                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 932
 933                 devp->hd_hpets = hpetp;
 934                 devp->hd_hpet = hpet;
 935                 devp->hd_timer = timer;
 936
 937                 /*
 938                  * If the timer was reserved by platform code,
 939                  * then make timer unavailable for opens.
 940                  */
 941                 if (hdp->hd_state & (1 << i)) {
 942                         devp->hd_flags = HPET_OPEN;
 943                         continue;
 944                 }
 945
 946                 init_waitqueue_head(&devp->hd_waitqueue);
 947         }
 948
 949         hpetp->hp_delta = hpet_calibrate(hpetp);
 950
 951 /* This clocksource driver currently only works on ia64 */
 952 #ifdef CONFIG_IA64
 953         if (!hpet_clocksource) {
 954                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 955                 clocksource_hpet.archdata.fsys_mmio = hpet_mctr;
 956                 clocksource_register_hz(&clocksource_hpet, hpetp->hp_tick_freq);
 957                 hpetp->hp_clocksource = &clocksource_hpet;
 958                 hpet_clocksource = &clocksource_hpet;
 959         }
 960 #endif
 961
 962         return 0;
 963 }
 964
 965 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 966 {
 967         struct hpet_data *hdp;
 968         acpi_status status;
 969         struct acpi_resource_address64 addr;
 970
 971         hdp = data;
 972
 973         status = acpi_resource_to_address64(res, &addr);
 974
 975         if (ACPI_SUCCESS(status)) {
 976                 hdp->hd_phys_address = addr.minimum;
 977                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 978
 979                 if (hpet_is_known(hdp)) {
 980                         iounmap(hdp->hd_address);
 981                         return AE_ALREADY_EXISTS;
 982                 }
 983         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 984                 struct acpi_resource_fixed_memory32 *fixmem32;
 985
 986                 fixmem32 = &res->data.fixed_memory32;
 987                 if (!fixmem32)
 988                         return AE_NO_MEMORY;
 989
 990                 hdp->hd_phys_address = fixmem32->address;
 991                 hdp->hd_address = ioremap(fixmem32->address,
 992                                                 HPET_RANGE_SIZE);
 993
 994                 if (hpet_is_known(hdp)) {
 995                         iounmap(hdp->hd_address);
 996                         return AE_ALREADY_EXISTS;
 997                 }
 998         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 999                 struct acpi_resource_extended_irq *irqp;
1000                 int i, irq;
1001
1002                 irqp = &res->data.extended_irq;
1003
1004                 for (i = 0; i < irqp->interrupt_count; i++) {
1005                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
1006                                       irqp->triggering, irqp->polarity);
1007                         if (irq < 0)
1008                                 return AE_ERROR;
1009
1010                         hdp->hd_irq[hdp->hd_nirqs] = irq;
1011                         hdp->hd_nirqs++;
1012                 }
1013         }
1014
1015         return AE_OK;
1016 }
1017
1018 static int hpet_acpi_add(struct acpi_device *device)
1019 {
1020         acpi_status result;
1021         struct hpet_data data;
1022
1023         memset(&data, 0, sizeof(data));
1024
1025         result =
1026             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
1027                                 hpet_resources, &data);
1028
1029         if (ACPI_FAILURE(result))
1030                 return -ENODEV;
1031
1032         if (!data.hd_address || !data.hd_nirqs) {
1033                 if (data.hd_address)
1034                         iounmap(data.hd_address);
1035                 printk("%s: no address or irqs in _CRS\n", __func__);
1036                 return -ENODEV;
1037         }
1038
1039         return hpet_alloc(&data);
1040 }
1041
1042 static int hpet_acpi_remove(struct acpi_device *device, int type)
1043 {
1044         /* XXX need to unregister clocksource, dealloc mem, etc */
1045         return -EINVAL;
1046 }
1047
1048 static const struct acpi_device_id hpet_device_ids[] = {
1049         {"PNP0103", 0},
1050         {"", 0},
1051 };
1052 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
1053
1054 static struct acpi_driver hpet_acpi_driver = {
1055         .name = "hpet",
1056         .ids = hpet_device_ids,
1057         .ops = {
1058                 .add = hpet_acpi_add,
1059                 .remove = hpet_acpi_remove,
1060                 },
1061 };
1062
1063 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1064
1065 static int __init hpet_init(void)
1066 {
1067         int result;
1068
1069         result = misc_register(&hpet_misc);
1070         if (result < 0)
1071                 return -ENODEV;
1072
1073         sysctl_header = register_sysctl_table(dev_root);
1074
1075         result = acpi_bus_register_driver(&hpet_acpi_driver);
1076         if (result < 0) {
1077                 if (sysctl_header)
1078                         unregister_sysctl_table(sysctl_header);
1079                 misc_deregister(&hpet_misc);
1080                 return result;
1081         }
1082
1083         return 0;
1084 }
1085
1086 static void __exit hpet_exit(void)
1087 {
1088         acpi_bus_unregister_driver(&hpet_acpi_driver);
1089
1090         if (sysctl_header)
1091                 unregister_sysctl_table(sysctl_header);
1092         misc_deregister(&hpet_misc);
1093
1094         return;
1095 }
1096
1097 module_init(hpet_init);
1098 module_exit(hpet_exit);
1099 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1100 MODULE_LICENSE("GPL");