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/irq.h>
  40 #include <asm/div64.h>
  41
  42 #include <linux/acpi.h>
  43 #include <acpi/acpi_bus.h>
  44 #include <linux/hpet.h>
  45
  46 /*
  47  * The High Precision Event Timer driver.
  48  * This driver is closely modelled after the rtc.c driver.
  49  * http://www.intel.com/hardwaredesign/hpetspec_1.pdf
  50  */
  51 #define HPET_USER_FREQ  (64)
  52 #define HPET_DRIFT      (500)
  53
  54 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
  55
  56
  57 /* WARNING -- don't get confused.  These macros are never used
  58  * to write the (single) counter, and rarely to read it.
  59  * They're badly named; to fix, someday.
  60  */
  61 #if BITS_PER_LONG == 64
  62 #define write_counter(V, MC)    writeq(V, MC)
  63 #define read_counter(MC)        readq(MC)
  64 #else
  65 #define write_counter(V, MC)    writel(V, MC)
  66 #define read_counter(MC)        readl(MC)
  67 #endif
  68
  69 static DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
  70 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  71
  72 /* This clocksource driver currently only works on ia64 */
  73 #ifdef CONFIG_IA64
  74 static void __iomem *hpet_mctr;
  75
  76 static cycle_t read_hpet(struct clocksource *cs)
  77 {
  78         return (cycle_t)read_counter((void __iomem *)hpet_mctr);
  79 }
  80
  81 static struct clocksource clocksource_hpet = {
  82         .name           = "hpet",
  83         .rating         = 250,
  84         .read           = read_hpet,
  85         .mask           = CLOCKSOURCE_MASK(64),
  86         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  87 };
  88 static struct clocksource *hpet_clocksource;
  89 #endif
  90
  91 /* A lock for concurrent access by app and isr hpet activity. */
  92 static DEFINE_SPINLOCK(hpet_lock);
  93
  94 #define HPET_DEV_NAME   (7)
  95
  96 struct hpet_dev {
  97         struct hpets *hd_hpets;
  98         struct hpet __iomem *hd_hpet;
  99         struct hpet_timer __iomem *hd_timer;
 100         unsigned long hd_ireqfreq;
 101         unsigned long hd_irqdata;
 102         wait_queue_head_t hd_waitqueue;
 103         struct fasync_struct *hd_async_queue;
 104         unsigned int hd_flags;
 105         unsigned int hd_irq;
 106         unsigned int hd_hdwirq;
 107         char hd_name[HPET_DEV_NAME];
 108 };
 109
 110 struct hpets {
 111         struct hpets *hp_next;
 112         struct hpet __iomem *hp_hpet;
 113         unsigned long hp_hpet_phys;
 114         struct clocksource *hp_clocksource;
 115         unsigned long long hp_tick_freq;
 116         unsigned long hp_delta;
 117         unsigned int hp_ntimer;
 118         unsigned int hp_which;
 119         struct hpet_dev hp_dev[1];
 120 };
 121
 122 static struct hpets *hpets;
 123
 124 #define HPET_OPEN               0x0001
 125 #define HPET_IE                 0x0002  /* interrupt enabled */
 126 #define HPET_PERIODIC           0x0004
 127 #define HPET_SHARED_IRQ         0x0008
 128
 129
 130 #ifndef readq
 131 static inline unsigned long long readq(void __iomem *addr)
 132 {
 133         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 134 }
 135 #endif
 136
 137 #ifndef writeq
 138 static inline void writeq(unsigned long long v, void __iomem *addr)
 139 {
 140         writel(v & 0xffffffff, addr);
 141         writel(v >> 32, addr + 4);
 142 }
 143 #endif
 144
 145 static irqreturn_t hpet_interrupt(int irq, void *data)
 146 {
 147         struct hpet_dev *devp;
 148         unsigned long isr;
 149
 150         devp = data;
 151         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 152
 153         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 154             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 155                 return IRQ_NONE;
 156
 157         spin_lock(&hpet_lock);
 158         devp->hd_irqdata++;
 159
 160         /*
 161          * For non-periodic timers, increment the accumulator.
 162          * This has the effect of treating non-periodic like periodic.
 163          */
 164         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 165                 unsigned long m, t, mc, base, k;
 166                 struct hpet __iomem *hpet = devp->hd_hpet;
 167                 struct hpets *hpetp = devp->hd_hpets;
 168
 169                 t = devp->hd_ireqfreq;
 170                 m = read_counter(&devp->hd_timer->hpet_compare);
 171                 mc = read_counter(&hpet->hpet_mc);
 172                 /* The time for the next interrupt would logically be t + m,
 173                  * however, if we are very unlucky and the interrupt is delayed
 174                  * for longer than t then we will completely miss the next
 175                  * interrupt if we set t + m and an application will hang.
 176                  * Therefore we need to make a more complex computation assuming
 177                  * that there exists a k for which the following is true:
 178                  * k * t + base < mc + delta
 179                  * (k + 1) * t + base > mc + delta
 180                  * where t is the interval in hpet ticks for the given freq,
 181                  * base is the theoretical start value 0 < base < t,
 182                  * mc is the main counter value at the time of the interrupt,
 183                  * delta is the time it takes to write the a value to the
 184                  * comparator.
 185                  * k may then be computed as (mc - base + delta) / t .
 186                  */
 187                 base = mc % t;
 188                 k = (mc - base + hpetp->hp_delta) / t;
 189                 write_counter(t * (k + 1) + base,
 190                               &devp->hd_timer->hpet_compare);
 191         }
 192
 193         if (devp->hd_flags & HPET_SHARED_IRQ)
 194                 writel(isr, &devp->hd_hpet->hpet_isr);
 195         spin_unlock(&hpet_lock);
 196
 197         wake_up_interruptible(&devp->hd_waitqueue);
 198
 199         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 200
 201         return IRQ_HANDLED;
 202 }
 203
 204 static void hpet_timer_set_irq(struct hpet_dev *devp)
 205 {
 206         unsigned long v;
 207         int irq, gsi;
 208         struct hpet_timer __iomem *timer;
 209
 210         spin_lock_irq(&hpet_lock);
 211         if (devp->hd_hdwirq) {
 212                 spin_unlock_irq(&hpet_lock);
 213                 return;
 214         }
 215
 216         timer = devp->hd_timer;
 217
 218         /* we prefer level triggered mode */
 219         v = readl(&timer->hpet_config);
 220         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
 221                 v |= Tn_INT_TYPE_CNF_MASK;
 222                 writel(v, &timer->hpet_config);
 223         }
 224         spin_unlock_irq(&hpet_lock);
 225
 226         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
 227                                  Tn_INT_ROUTE_CAP_SHIFT;
 228
 229         /*
 230          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
 231          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
 232          */
 233         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 234                 v &= ~0xf3df;
 235         else
 236                 v &= ~0xffff;
 237
 238         for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
 239                 if (irq >= nr_irqs) {
 240                         irq = HPET_MAX_IRQ;
 241                         break;
 242                 }
 243
 244                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
 245                                         ACPI_ACTIVE_LOW);
 246                 if (gsi > 0)
 247                         break;
 248
 249                 /* FIXME: Setup interrupt source table */
 250         }
 251
 252         if (irq < HPET_MAX_IRQ) {
 253                 spin_lock_irq(&hpet_lock);
 254                 v = readl(&timer->hpet_config);
 255                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 256                 writel(v, &timer->hpet_config);
 257                 devp->hd_hdwirq = gsi;
 258                 spin_unlock_irq(&hpet_lock);
 259         }
 260         return;
 261 }
 262
 263 static int hpet_open(struct inode *inode, struct file *file)
 264 {
 265         struct hpet_dev *devp;
 266         struct hpets *hpetp;
 267         int i;
 268
 269         if (file->f_mode & FMODE_WRITE)
 270                 return -EINVAL;
 271
 272         mutex_lock(&hpet_mutex);
 273         spin_lock_irq(&hpet_lock);
 274
 275         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 276                 for (i = 0; i < hpetp->hp_ntimer; i++)
 277                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
 278                                 continue;
 279                         else {
 280                                 devp = &hpetp->hp_dev[i];
 281                                 break;
 282                         }
 283
 284         if (!devp) {
 285                 spin_unlock_irq(&hpet_lock);
 286                 mutex_unlock(&hpet_mutex);
 287                 return -EBUSY;
 288         }
 289
 290         file->private_data = devp;
 291         devp->hd_irqdata = 0;
 292         devp->hd_flags |= HPET_OPEN;
 293         spin_unlock_irq(&hpet_lock);
 294         mutex_unlock(&hpet_mutex);
 295
 296         hpet_timer_set_irq(devp);
 297
 298         return 0;
 299 }
 300
 301 static ssize_t
 302 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 303 {
 304         DECLARE_WAITQUEUE(wait, current);
 305         unsigned long data;
 306         ssize_t retval;
 307         struct hpet_dev *devp;
 308
 309         devp = file->private_data;
 310         if (!devp->hd_ireqfreq)
 311                 return -EIO;
 312
 313         if (count < sizeof(unsigned long))
 314                 return -EINVAL;
 315
 316         add_wait_queue(&devp->hd_waitqueue, &wait);
 317
 318         for ( ; ; ) {
 319                 set_current_state(TASK_INTERRUPTIBLE);
 320
 321                 spin_lock_irq(&hpet_lock);
 322                 data = devp->hd_irqdata;
 323                 devp->hd_irqdata = 0;
 324                 spin_unlock_irq(&hpet_lock);
 325
 326                 if (data)
 327                         break;
 328                 else if (file->f_flags & O_NONBLOCK) {
 329                         retval = -EAGAIN;
 330                         goto out;
 331                 } else if (signal_pending(current)) {
 332                         retval = -ERESTARTSYS;
 333                         goto out;
 334                 }
 335                 schedule();
 336         }
 337
 338         retval = put_user(data, (unsigned long __user *)buf);
 339         if (!retval)
 340                 retval = sizeof(unsigned long);
 341 out:
 342         __set_current_state(TASK_RUNNING);
 343         remove_wait_queue(&devp->hd_waitqueue, &wait);
 344
 345         return retval;
 346 }
 347
 348 static unsigned int hpet_poll(struct file *file, poll_table * wait)
 349 {
 350         unsigned long v;
 351         struct hpet_dev *devp;
 352
 353         devp = file->private_data;
 354
 355         if (!devp->hd_ireqfreq)
 356                 return 0;
 357
 358         poll_wait(file, &devp->hd_waitqueue, wait);
 359
 360         spin_lock_irq(&hpet_lock);
 361         v = devp->hd_irqdata;
 362         spin_unlock_irq(&hpet_lock);
 363
 364         if (v != 0)
 365                 return POLLIN | POLLRDNORM;
 366
 367         return 0;
 368 }
 369
 370 #ifdef CONFIG_HPET_MMAP
 371 #ifdef CONFIG_HPET_MMAP_DEFAULT
 372 static int hpet_mmap_enabled = 1;
 373 #else
 374 static int hpet_mmap_enabled = 0;
 375 #endif
 376
 377 static __init int hpet_mmap_enable(char *str)
 378 {
 379         get_option(&str, &hpet_mmap_enabled);
 380         pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
 381         return 1;
 382 }
 383 __setup("hpet_mmap", hpet_mmap_enable);
 384
 385 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 386 {
 387         struct hpet_dev *devp;
 388         unsigned long addr;
 389
 390         if (!hpet_mmap_enabled)
 391                 return -EACCES;
 392
 393         devp = file->private_data;
 394         addr = devp->hd_hpets->hp_hpet_phys;
 395
 396         if (addr & (PAGE_SIZE - 1))
 397                 return -ENOSYS;
 398
 399         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 400         return vm_iomap_memory(vma, addr, PAGE_SIZE);
 401 }
 402 #else
 403 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 404 {
 405         return -ENOSYS;
 406 }
 407 #endif
 408
 409 static int hpet_fasync(int fd, struct file *file, int on)
 410 {
 411         struct hpet_dev *devp;
 412
 413         devp = file->private_data;
 414
 415         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 416                 return 0;
 417         else
 418                 return -EIO;
 419 }
 420
 421 static int hpet_release(struct inode *inode, struct file *file)
 422 {
 423         struct hpet_dev *devp;
 424         struct hpet_timer __iomem *timer;
 425         int irq = 0;
 426
 427         devp = file->private_data;
 428         timer = devp->hd_timer;
 429
 430         spin_lock_irq(&hpet_lock);
 431
 432         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 433                &timer->hpet_config);
 434
 435         irq = devp->hd_irq;
 436         devp->hd_irq = 0;
 437
 438         devp->hd_ireqfreq = 0;
 439
 440         if (devp->hd_flags & HPET_PERIODIC
 441             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 442                 unsigned long v;
 443
 444                 v = readq(&timer->hpet_config);
 445                 v ^= Tn_TYPE_CNF_MASK;
 446                 writeq(v, &timer->hpet_config);
 447         }
 448
 449         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 450         spin_unlock_irq(&hpet_lock);
 451
 452         if (irq)
 453                 free_irq(irq, devp);
 454
 455         file->private_data = NULL;
 456         return 0;
 457 }
 458
 459 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 460 {
 461         struct hpet_timer __iomem *timer;
 462         struct hpet __iomem *hpet;
 463         struct hpets *hpetp;
 464         int irq;
 465         unsigned long g, v, t, m;
 466         unsigned long flags, isr;
 467
 468         timer = devp->hd_timer;
 469         hpet = devp->hd_hpet;
 470         hpetp = devp->hd_hpets;
 471
 472         if (!devp->hd_ireqfreq)
 473                 return -EIO;
 474
 475         spin_lock_irq(&hpet_lock);
 476
 477         if (devp->hd_flags & HPET_IE) {
 478                 spin_unlock_irq(&hpet_lock);
 479                 return -EBUSY;
 480         }
 481
 482         devp->hd_flags |= HPET_IE;
 483
 484         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 485                 devp->hd_flags |= HPET_SHARED_IRQ;
 486         spin_unlock_irq(&hpet_lock);
 487
 488         irq = devp->hd_hdwirq;
 489
 490         if (irq) {
 491                 unsigned long irq_flags;
 492
 493                 if (devp->hd_flags & HPET_SHARED_IRQ) {
 494                         /*
 495                          * To prevent the interrupt handler from seeing an
 496                          * unwanted interrupt status bit, program the timer
 497                          * so that it will not fire in the near future ...
 498                          */
 499                         writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
 500                                &timer->hpet_config);
 501                         write_counter(read_counter(&hpet->hpet_mc),
 502                                       &timer->hpet_compare);
 503                         /* ... and clear any left-over status. */
 504                         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 505                         writel(isr, &hpet->hpet_isr);
 506                 }
 507
 508                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 509                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
 510                 if (request_irq(irq, hpet_interrupt, irq_flags,
 511                                 devp->hd_name, (void *)devp)) {
 512                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 513                         irq = 0;
 514                 }
 515         }
 516
 517         if (irq == 0) {
 518                 spin_lock_irq(&hpet_lock);
 519                 devp->hd_flags ^= HPET_IE;
 520                 spin_unlock_irq(&hpet_lock);
 521                 return -EIO;
 522         }
 523
 524         devp->hd_irq = irq;
 525         t = devp->hd_ireqfreq;
 526         v = readq(&timer->hpet_config);
 527
 528         /* 64-bit comparators are not yet supported through the ioctls,
 529          * so force this into 32-bit mode if it supports both modes
 530          */
 531         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 532
 533         if (devp->hd_flags & HPET_PERIODIC) {
 534                 g |= Tn_TYPE_CNF_MASK;
 535                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 536                 writeq(v, &timer->hpet_config);
 537                 local_irq_save(flags);
 538
 539                 /*
 540                  * NOTE: First we modify the hidden accumulator
 541                  * register supported by periodic-capable comparators.
 542                  * We never want to modify the (single) counter; that
 543                  * would affect all the comparators. The value written
 544                  * is the counter value when the first interrupt is due.
 545                  */
 546                 m = read_counter(&hpet->hpet_mc);
 547                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 548                 /*
 549                  * Then we modify the comparator, indicating the period
 550                  * for subsequent interrupt.
 551                  */
 552                 write_counter(t, &timer->hpet_compare);
 553         } else {
 554                 local_irq_save(flags);
 555                 m = read_counter(&hpet->hpet_mc);
 556                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 557         }
 558
 559         if (devp->hd_flags & HPET_SHARED_IRQ) {
 560                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 561                 writel(isr, &hpet->hpet_isr);
 562         }
 563         writeq(g, &timer->hpet_config);
 564         local_irq_restore(flags);
 565
 566         return 0;
 567 }
 568
 569 /* converts Hz to number of timer ticks */
 570 static inline unsigned long hpet_time_div(struct hpets *hpets,
 571                                           unsigned long dis)
 572 {
 573         unsigned long long m;
 574
 575         m = hpets->hp_tick_freq + (dis >> 1);
 576         do_div(m, dis);
 577         return (unsigned long)m;
 578 }
 579
 580 static int
 581 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg,
 582                   struct hpet_info *info)
 583 {
 584         struct hpet_timer __iomem *timer;
 585         struct hpet __iomem *hpet;
 586         struct hpets *hpetp;
 587         int err;
 588         unsigned long v;
 589
 590         switch (cmd) {
 591         case HPET_IE_OFF:
 592         case HPET_INFO:
 593         case HPET_EPI:
 594         case HPET_DPI:
 595         case HPET_IRQFREQ:
 596                 timer = devp->hd_timer;
 597                 hpet = devp->hd_hpet;
 598                 hpetp = devp->hd_hpets;
 599                 break;
 600         case HPET_IE_ON:
 601                 return hpet_ioctl_ieon(devp);
 602         default:
 603                 return -EINVAL;
 604         }
 605
 606         err = 0;
 607
 608         switch (cmd) {
 609         case HPET_IE_OFF:
 610                 if ((devp->hd_flags & HPET_IE) == 0)
 611                         break;
 612                 v = readq(&timer->hpet_config);
 613                 v &= ~Tn_INT_ENB_CNF_MASK;
 614                 writeq(v, &timer->hpet_config);
 615                 if (devp->hd_irq) {
 616                         free_irq(devp->hd_irq, devp);
 617                         devp->hd_irq = 0;
 618                 }
 619                 devp->hd_flags ^= HPET_IE;
 620                 break;
 621         case HPET_INFO:
 622                 {
 623                         memset(info, 0, sizeof(*info));
 624                         if (devp->hd_ireqfreq)
 625                                 info->hi_ireqfreq =
 626                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 627                         info->hi_flags =
 628                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 629                         info->hi_hpet = hpetp->hp_which;
 630                         info->hi_timer = devp - hpetp->hp_dev;
 631                         break;
 632                 }
 633         case HPET_EPI:
 634                 v = readq(&timer->hpet_config);
 635                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 636                         err = -ENXIO;
 637                         break;
 638                 }
 639                 devp->hd_flags |= HPET_PERIODIC;
 640                 break;
 641         case HPET_DPI:
 642                 v = readq(&timer->hpet_config);
 643                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 644                         err = -ENXIO;
 645                         break;
 646                 }
 647                 if (devp->hd_flags & HPET_PERIODIC &&
 648                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 649                         v = readq(&timer->hpet_config);
 650                         v ^= Tn_TYPE_CNF_MASK;
 651                         writeq(v, &timer->hpet_config);
 652                 }
 653                 devp->hd_flags &= ~HPET_PERIODIC;
 654                 break;
 655         case HPET_IRQFREQ:
 656                 if ((arg > hpet_max_freq) &&
 657                     !capable(CAP_SYS_RESOURCE)) {
 658                         err = -EACCES;
 659                         break;
 660                 }
 661
 662                 if (!arg) {
 663                         err = -EINVAL;
 664                         break;
 665                 }
 666
 667                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 668         }
 669
 670         return err;
 671 }
 672
 673 static long
 674 hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 675 {
 676         struct hpet_info info;
 677         int err;
 678
 679         mutex_lock(&hpet_mutex);
 680         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 681         mutex_unlock(&hpet_mutex);
 682
 683         if ((cmd == HPET_INFO) && !err &&
 684             (copy_to_user((void __user *)arg, &info, sizeof(info))))
 685                 err = -EFAULT;
 686
 687         return err;
 688 }
 689
 690 #ifdef CONFIG_COMPAT
 691 struct compat_hpet_info {
 692         compat_ulong_t hi_ireqfreq;     /* Hz */
 693         compat_ulong_t hi_flags;        /* information */
 694         unsigned short hi_hpet;
 695         unsigned short hi_timer;
 696 };
 697
 698 static long
 699 hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 700 {
 701         struct hpet_info info;
 702         int err;
 703
 704         mutex_lock(&hpet_mutex);
 705         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 706         mutex_unlock(&hpet_mutex);
 707
 708         if ((cmd == HPET_INFO) && !err) {
 709                 struct compat_hpet_info __user *u = compat_ptr(arg);
 710                 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
 711                     put_user(info.hi_flags, &u->hi_flags) ||
 712                     put_user(info.hi_hpet, &u->hi_hpet) ||
 713                     put_user(info.hi_timer, &u->hi_timer))
 714                         err = -EFAULT;
 715         }
 716
 717         return err;
 718 }
 719 #endif
 720
 721 static const struct file_operations hpet_fops = {
 722         .owner = THIS_MODULE,
 723         .llseek = no_llseek,
 724         .read = hpet_read,
 725         .poll = hpet_poll,
 726         .unlocked_ioctl = hpet_ioctl,
 727 #ifdef CONFIG_COMPAT
 728         .compat_ioctl = hpet_compat_ioctl,
 729 #endif
 730         .open = hpet_open,
 731         .release = hpet_release,
 732         .fasync = hpet_fasync,
 733         .mmap = hpet_mmap,
 734 };
 735
 736 static int hpet_is_known(struct hpet_data *hdp)
 737 {
 738         struct hpets *hpetp;
 739
 740         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 741                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 742                         return 1;
 743
 744         return 0;
 745 }
 746
 747 static struct ctl_table hpet_table[] = {
 748         {
 749          .procname = "max-user-freq",
 750          .data = &hpet_max_freq,
 751          .maxlen = sizeof(int),
 752          .mode = 0644,
 753          .proc_handler = proc_dointvec,
 754          },
 755         {}
 756 };
 757
 758 static struct ctl_table hpet_root[] = {
 759         {
 760          .procname = "hpet",
 761          .maxlen = 0,
 762          .mode = 0555,
 763          .child = hpet_table,
 764          },
 765         {}
 766 };
 767
 768 static struct ctl_table dev_root[] = {
 769         {
 770          .procname = "dev",
 771          .maxlen = 0,
 772          .mode = 0555,
 773          .child = hpet_root,
 774          },
 775         {}
 776 };
 777
 778 static struct ctl_table_header *sysctl_header;
 779
 780 /*
 781  * Adjustment for when arming the timer with
 782  * initial conditions.  That is, main counter
 783  * ticks expired before interrupts are enabled.
 784  */
 785 #define TICK_CALIBRATE  (1000UL)
 786
 787 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 788 {
 789         struct hpet_timer __iomem *timer = NULL;
 790         unsigned long t, m, count, i, flags, start;
 791         struct hpet_dev *devp;
 792         int j;
 793         struct hpet __iomem *hpet;
 794
 795         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 796                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 797                         timer = devp->hd_timer;
 798                         break;
 799                 }
 800
 801         if (!timer)
 802                 return 0;
 803
 804         hpet = hpetp->hp_hpet;
 805         t = read_counter(&timer->hpet_compare);
 806
 807         i = 0;
 808         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 809
 810         local_irq_save(flags);
 811
 812         start = read_counter(&hpet->hpet_mc);
 813
 814         do {
 815                 m = read_counter(&hpet->hpet_mc);
 816                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 817         } while (i++, (m - start) < count);
 818
 819         local_irq_restore(flags);
 820
 821         return (m - start) / i;
 822 }
 823
 824 static unsigned long hpet_calibrate(struct hpets *hpetp)
 825 {
 826         unsigned long ret = ~0UL;
 827         unsigned long tmp;
 828
 829         /*
 830          * Try to calibrate until return value becomes stable small value.
 831          * If SMI interruption occurs in calibration loop, the return value
 832          * will be big. This avoids its impact.
 833          */
 834         for ( ; ; ) {
 835                 tmp = __hpet_calibrate(hpetp);
 836                 if (ret <= tmp)
 837                         break;
 838                 ret = tmp;
 839         }
 840
 841         return ret;
 842 }
 843
 844 int hpet_alloc(struct hpet_data *hdp)
 845 {
 846         u64 cap, mcfg;
 847         struct hpet_dev *devp;
 848         u32 i, ntimer;
 849         struct hpets *hpetp;
 850         size_t siz;
 851         struct hpet __iomem *hpet;
 852         static struct hpets *last;
 853         unsigned long period;
 854         unsigned long long temp;
 855         u32 remainder;
 856
 857         /*
 858          * hpet_alloc can be called by platform dependent code.
 859          * If platform dependent code has allocated the hpet that
 860          * ACPI has also reported, then we catch it here.
 861          */
 862         if (hpet_is_known(hdp)) {
 863                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 864                         __func__);
 865                 return 0;
 866         }
 867
 868         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 869                                       sizeof(struct hpet_dev));
 870
 871         hpetp = kzalloc(siz, GFP_KERNEL);
 872
 873         if (!hpetp)
 874                 return -ENOMEM;
 875
 876         hpetp->hp_which = hpet_nhpet++;
 877         hpetp->hp_hpet = hdp->hd_address;
 878         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 879
 880         hpetp->hp_ntimer = hdp->hd_nirqs;
 881
 882         for (i = 0; i < hdp->hd_nirqs; i++)
 883                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 884
 885         hpet = hpetp->hp_hpet;
 886
 887         cap = readq(&hpet->hpet_cap);
 888
 889         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 890
 891         if (hpetp->hp_ntimer != ntimer) {
 892                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 893                        " with number of timers\n");
 894                 kfree(hpetp);
 895                 return -ENODEV;
 896         }
 897
 898         if (last)
 899                 last->hp_next = hpetp;
 900         else
 901                 hpets = hpetp;
 902
 903         last = hpetp;
 904
 905         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 906                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 907         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 908         temp += period >> 1; /* round */
 909         do_div(temp, period);
 910         hpetp->hp_tick_freq = temp; /* ticks per second */
 911
 912         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 913                 hpetp->hp_which, hdp->hd_phys_address,
 914                 hpetp->hp_ntimer > 1 ? "s" : "");
 915         for (i = 0; i < hpetp->hp_ntimer; i++)
 916                 printk(KERN_CONT "%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 917         printk(KERN_CONT "\n");
 918
 919         temp = hpetp->hp_tick_freq;
 920         remainder = do_div(temp, 1000000);
 921         printk(KERN_INFO
 922                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 923                 hpetp->hp_which, hpetp->hp_ntimer,
 924                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 925                 (unsigned) temp, remainder);
 926
 927         mcfg = readq(&hpet->hpet_config);
 928         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 929                 write_counter(0L, &hpet->hpet_mc);
 930                 mcfg |= HPET_ENABLE_CNF_MASK;
 931                 writeq(mcfg, &hpet->hpet_config);
 932         }
 933
 934         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 935                 struct hpet_timer __iomem *timer;
 936
 937                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 938
 939                 devp->hd_hpets = hpetp;
 940                 devp->hd_hpet = hpet;
 941                 devp->hd_timer = timer;
 942
 943                 /*
 944                  * If the timer was reserved by platform code,
 945                  * then make timer unavailable for opens.
 946                  */
 947                 if (hdp->hd_state & (1 << i)) {
 948                         devp->hd_flags = HPET_OPEN;
 949                         continue;
 950                 }
 951
 952                 init_waitqueue_head(&devp->hd_waitqueue);
 953         }
 954
 955         hpetp->hp_delta = hpet_calibrate(hpetp);
 956
 957 /* This clocksource driver currently only works on ia64 */
 958 #ifdef CONFIG_IA64
 959         if (!hpet_clocksource) {
 960                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 961                 clocksource_hpet.archdata.fsys_mmio = hpet_mctr;
 962                 clocksource_register_hz(&clocksource_hpet, hpetp->hp_tick_freq);
 963                 hpetp->hp_clocksource = &clocksource_hpet;
 964                 hpet_clocksource = &clocksource_hpet;
 965         }
 966 #endif
 967
 968         return 0;
 969 }
 970
 971 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 972 {
 973         struct hpet_data *hdp;
 974         acpi_status status;
 975         struct acpi_resource_address64 addr;
 976
 977         hdp = data;
 978
 979         status = acpi_resource_to_address64(res, &addr);
 980
 981         if (ACPI_SUCCESS(status)) {
 982                 hdp->hd_phys_address = addr.minimum;
 983                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 984
 985                 if (hpet_is_known(hdp)) {
 986                         iounmap(hdp->hd_address);
 987                         return AE_ALREADY_EXISTS;
 988                 }
 989         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 990                 struct acpi_resource_fixed_memory32 *fixmem32;
 991
 992                 fixmem32 = &res->data.fixed_memory32;
 993
 994                 hdp->hd_phys_address = fixmem32->address;
 995                 hdp->hd_address = ioremap(fixmem32->address,
 996                                                 HPET_RANGE_SIZE);
 997
 998                 if (hpet_is_known(hdp)) {
 999                         iounmap(hdp->hd_address);
1000                         return AE_ALREADY_EXISTS;
1001                 }
1002         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
1003                 struct acpi_resource_extended_irq *irqp;
1004                 int i, irq;
1005
1006                 irqp = &res->data.extended_irq;
1007
1008                 for (i = 0; i < irqp->interrupt_count; i++) {
1009                         if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
1010                                 break;
1011
1012                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
1013                                       irqp->triggering, irqp->polarity);
1014                         if (irq < 0)
1015                                 return AE_ERROR;
1016
1017                         hdp->hd_irq[hdp->hd_nirqs] = irq;
1018                         hdp->hd_nirqs++;
1019                 }
1020         }
1021
1022         return AE_OK;
1023 }
1024
1025 static int hpet_acpi_add(struct acpi_device *device)
1026 {
1027         acpi_status result;
1028         struct hpet_data data;
1029
1030         memset(&data, 0, sizeof(data));
1031
1032         result =
1033             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
1034                                 hpet_resources, &data);
1035
1036         if (ACPI_FAILURE(result))
1037                 return -ENODEV;
1038
1039         if (!data.hd_address || !data.hd_nirqs) {
1040                 if (data.hd_address)
1041                         iounmap(data.hd_address);
1042                 printk("%s: no address or irqs in _CRS\n", __func__);
1043                 return -ENODEV;
1044         }
1045
1046         return hpet_alloc(&data);
1047 }
1048
1049 static int hpet_acpi_remove(struct acpi_device *device)
1050 {
1051         /* XXX need to unregister clocksource, dealloc mem, etc */
1052         return -EINVAL;
1053 }
1054
1055 static const struct acpi_device_id hpet_device_ids[] = {
1056         {"PNP0103", 0},
1057         {"", 0},
1058 };
1059 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
1060
1061 static struct acpi_driver hpet_acpi_driver = {
1062         .name = "hpet",
1063         .ids = hpet_device_ids,
1064         .ops = {
1065                 .add = hpet_acpi_add,
1066                 .remove = hpet_acpi_remove,
1067                 },
1068 };
1069
1070 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1071
1072 static int __init hpet_init(void)
1073 {
1074         int result;
1075
1076         result = misc_register(&hpet_misc);
1077         if (result < 0)
1078                 return -ENODEV;
1079
1080         sysctl_header = register_sysctl_table(dev_root);
1081
1082         result = acpi_bus_register_driver(&hpet_acpi_driver);
1083         if (result < 0) {
1084                 if (sysctl_header)
1085                         unregister_sysctl_table(sysctl_header);
1086                 misc_deregister(&hpet_misc);
1087                 return result;
1088         }
1089
1090         return 0;
1091 }
1092
1093 static void __exit hpet_exit(void)
1094 {
1095         acpi_bus_unregister_driver(&hpet_acpi_driver);
1096
1097         if (sysctl_header)
1098                 unregister_sysctl_table(sysctl_header);
1099         misc_deregister(&hpet_misc);
1100
1101         return;
1102 }
1103
1104 module_init(hpet_init);
1105 module_exit(hpet_exit);
1106 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1107 MODULE_LICENSE("GPL");