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