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/config.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/types.h>
  19 #include <linux/miscdevice.h>
  20 #include <linux/major.h>
  21 #include <linux/ioport.h>
  22 #include <linux/fcntl.h>
  23 #include <linux/init.h>
  24 #include <linux/poll.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
  32 #include <asm/current.h>
  33 #include <asm/uaccess.h>
  34 #include <asm/system.h>
  35 #include <asm/io.h>
  36 #include <asm/irq.h>
  37 #include <asm/bitops.h>
  38 #include <asm/div64.h>
  39
  40 #include <linux/acpi.h>
  41 #include <acpi/acpi_bus.h>
  42 #include <linux/hpet.h>
  43
  44 /*
  45  * The High Precision Event Timer driver.
  46  * This driver is closely modelled after the rtc.c driver.
  47  * http://www.intel.com/labs/platcomp/hpet/hpetspec.htm
  48  */
  49 #define HPET_USER_FREQ  (64)
  50 #define HPET_DRIFT      (500)
  51
  52 static u32 hpet_ntimer, hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  53
  54 /* A lock for concurrent access by app and isr hpet activity. */
  55 static spinlock_t hpet_lock = SPIN_LOCK_UNLOCKED;
  56 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
  57 static spinlock_t hpet_task_lock = SPIN_LOCK_UNLOCKED;
  58
  59 #define HPET_DEV_NAME   (7)
  60
  61 struct hpet_dev {
  62         struct hpets *hd_hpets;
  63         struct hpet __iomem *hd_hpet;
  64         struct hpet_timer __iomem *hd_timer;
  65         unsigned long hd_ireqfreq;
  66         unsigned long hd_irqdata;
  67         wait_queue_head_t hd_waitqueue;
  68         struct fasync_struct *hd_async_queue;
  69         struct hpet_task *hd_task;
  70         unsigned int hd_flags;
  71         unsigned int hd_irq;
  72         unsigned int hd_hdwirq;
  73         char hd_name[HPET_DEV_NAME];
  74 };
  75
  76 struct hpets {
  77         struct hpets *hp_next;
  78         struct hpet __iomem *hp_hpet;
  79         unsigned long hp_period;
  80         unsigned long hp_delta;
  81         unsigned int hp_ntimer;
  82         unsigned int hp_which;
  83         struct hpet_dev hp_dev[1];
  84 };
  85
  86 static struct hpets *hpets;
  87
  88 #define HPET_OPEN               0x0001
  89 #define HPET_IE                 0x0002  /* interrupt enabled */
  90 #define HPET_PERIODIC           0x0004
  91
  92 #if BITS_PER_LONG == 64
  93 #define write_counter(V, MC)    writeq(V, MC)
  94 #define read_counter(MC)        readq(MC)
  95 #else
  96 #define write_counter(V, MC)    writel(V, MC)
  97 #define read_counter(MC)        readl(MC)
  98 #endif
  99
 100 #ifndef readq
 101 static unsigned long long __inline readq(void __iomem *addr)
 102 {
 103         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 104 }
 105 #endif
 106
 107 #ifndef writeq
 108 static void __inline writeq(unsigned long long v, void __iomem *addr)
 109 {
 110         writel(v & 0xffffffff, addr);
 111         writel(v >> 32, addr + 4);
 112 }
 113 #endif
 114
 115 static irqreturn_t hpet_interrupt(int irq, void *data, struct pt_regs *regs)
 116 {
 117         struct hpet_dev *devp;
 118         unsigned long isr;
 119
 120         devp = data;
 121
 122         spin_lock(&hpet_lock);
 123         devp->hd_irqdata++;
 124
 125         /*
 126          * For non-periodic timers, increment the accumulator.
 127          * This has the effect of treating non-periodic like periodic.
 128          */
 129         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 130                 unsigned long m, t;
 131
 132                 t = devp->hd_ireqfreq;
 133                 m = read_counter(&devp->hd_hpet->hpet_mc);
 134                 write_counter(t + m + devp->hd_hpets->hp_delta,
 135                               &devp->hd_timer->hpet_compare);
 136         }
 137
 138         isr = (1 << (devp - devp->hd_hpets->hp_dev));
 139         writeq(isr, &devp->hd_hpet->hpet_isr);
 140         spin_unlock(&hpet_lock);
 141
 142         spin_lock(&hpet_task_lock);
 143         if (devp->hd_task)
 144                 devp->hd_task->ht_func(devp->hd_task->ht_data);
 145         spin_unlock(&hpet_task_lock);
 146
 147         wake_up_interruptible(&devp->hd_waitqueue);
 148
 149         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 150
 151         return IRQ_HANDLED;
 152 }
 153
 154 static int hpet_open(struct inode *inode, struct file *file)
 155 {
 156         struct hpet_dev *devp;
 157         struct hpets *hpetp;
 158         int i;
 159
 160         if (file->f_mode & FMODE_WRITE)
 161                 return -EINVAL;
 162
 163         spin_lock_irq(&hpet_lock);
 164
 165         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 166                 for (i = 0; i < hpetp->hp_ntimer; i++)
 167                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
 168                             || hpetp->hp_dev[i].hd_task)
 169                                 continue;
 170                         else {
 171                                 devp = &hpetp->hp_dev[i];
 172                                 break;
 173                         }
 174
 175         if (!devp) {
 176                 spin_unlock_irq(&hpet_lock);
 177                 return -EBUSY;
 178         }
 179
 180         file->private_data = devp;
 181         devp->hd_irqdata = 0;
 182         devp->hd_flags |= HPET_OPEN;
 183         spin_unlock_irq(&hpet_lock);
 184
 185         return 0;
 186 }
 187
 188 static ssize_t
 189 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 190 {
 191         DECLARE_WAITQUEUE(wait, current);
 192         unsigned long data;
 193         ssize_t retval;
 194         struct hpet_dev *devp;
 195
 196         devp = file->private_data;
 197         if (!devp->hd_ireqfreq)
 198                 return -EIO;
 199
 200         if (count < sizeof(unsigned long))
 201                 return -EINVAL;
 202
 203         add_wait_queue(&devp->hd_waitqueue, &wait);
 204
 205         for ( ; ; ) {
 206                 set_current_state(TASK_INTERRUPTIBLE);
 207
 208                 spin_lock_irq(&hpet_lock);
 209                 data = devp->hd_irqdata;
 210                 devp->hd_irqdata = 0;
 211                 spin_unlock_irq(&hpet_lock);
 212
 213                 if (data)
 214                         break;
 215                 else if (file->f_flags & O_NONBLOCK) {
 216                         retval = -EAGAIN;
 217                         goto out;
 218                 } else if (signal_pending(current)) {
 219                         retval = -ERESTARTSYS;
 220                         goto out;
 221                 }
 222                 schedule();
 223         }
 224
 225         retval = put_user(data, (unsigned long __user *)buf);
 226         if (!retval)
 227                 retval = sizeof(unsigned long);
 228 out:
 229         __set_current_state(TASK_RUNNING);
 230         remove_wait_queue(&devp->hd_waitqueue, &wait);
 231
 232         return retval;
 233 }
 234
 235 static unsigned int hpet_poll(struct file *file, poll_table * wait)
 236 {
 237         unsigned long v;
 238         struct hpet_dev *devp;
 239
 240         devp = file->private_data;
 241
 242         if (!devp->hd_ireqfreq)
 243                 return 0;
 244
 245         poll_wait(file, &devp->hd_waitqueue, wait);
 246
 247         spin_lock_irq(&hpet_lock);
 248         v = devp->hd_irqdata;
 249         spin_unlock_irq(&hpet_lock);
 250
 251         if (v != 0)
 252                 return POLLIN | POLLRDNORM;
 253
 254         return 0;
 255 }
 256
 257 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 258 {
 259 #ifdef  CONFIG_HPET_MMAP
 260         struct hpet_dev *devp;
 261         unsigned long addr;
 262
 263         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
 264                 return -EINVAL;
 265
 266         devp = file->private_data;
 267         addr = (unsigned long)devp->hd_hpet;
 268
 269         if (addr & (PAGE_SIZE - 1))
 270                 return -ENOSYS;
 271
 272         vma->vm_flags |= VM_IO;
 273         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 274         addr = __pa(addr);
 275
 276         if (remap_page_range
 277             (vma, vma->vm_start, addr, PAGE_SIZE, vma->vm_page_prot)) {
 278                 printk(KERN_ERR "remap_page_range failed in hpet.c\n");
 279                 return -EAGAIN;
 280         }
 281
 282         return 0;
 283 #else
 284         return -ENOSYS;
 285 #endif
 286 }
 287
 288 static int hpet_fasync(int fd, struct file *file, int on)
 289 {
 290         struct hpet_dev *devp;
 291
 292         devp = file->private_data;
 293
 294         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 295                 return 0;
 296         else
 297                 return -EIO;
 298 }
 299
 300 static int hpet_release(struct inode *inode, struct file *file)
 301 {
 302         struct hpet_dev *devp;
 303         struct hpet_timer __iomem *timer;
 304         int irq = 0;
 305
 306         devp = file->private_data;
 307         timer = devp->hd_timer;
 308
 309         spin_lock_irq(&hpet_lock);
 310
 311         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 312                &timer->hpet_config);
 313
 314         irq = devp->hd_irq;
 315         devp->hd_irq = 0;
 316
 317         devp->hd_ireqfreq = 0;
 318
 319         if (devp->hd_flags & HPET_PERIODIC
 320             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 321                 unsigned long v;
 322
 323                 v = readq(&timer->hpet_config);
 324                 v ^= Tn_TYPE_CNF_MASK;
 325                 writeq(v, &timer->hpet_config);
 326         }
 327
 328         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 329         spin_unlock_irq(&hpet_lock);
 330
 331         if (irq)
 332                 free_irq(irq, devp);
 333
 334         if (file->f_flags & FASYNC)
 335                 hpet_fasync(-1, file, 0);
 336
 337         file->private_data = NULL;
 338         return 0;
 339 }
 340
 341 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
 342
 343 static int
 344 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 345            unsigned long arg)
 346 {
 347         struct hpet_dev *devp;
 348
 349         devp = file->private_data;
 350         return hpet_ioctl_common(devp, cmd, arg, 0);
 351 }
 352
 353 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 354 {
 355         struct hpet_timer __iomem *timer;
 356         struct hpet __iomem *hpet;
 357         struct hpets *hpetp;
 358         int irq;
 359         unsigned long g, v, t, m;
 360         unsigned long flags, isr;
 361
 362         timer = devp->hd_timer;
 363         hpet = devp->hd_hpet;
 364         hpetp = devp->hd_hpets;
 365
 366         v = readq(&timer->hpet_config);
 367         spin_lock_irq(&hpet_lock);
 368
 369         if (devp->hd_flags & HPET_IE) {
 370                 spin_unlock_irq(&hpet_lock);
 371                 return -EBUSY;
 372         }
 373
 374         devp->hd_flags |= HPET_IE;
 375         spin_unlock_irq(&hpet_lock);
 376
 377         t = readq(&timer->hpet_config);
 378         irq = devp->hd_hdwirq;
 379
 380         if (irq) {
 381                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 382
 383                 if (request_irq
 384                     (irq, hpet_interrupt, SA_INTERRUPT, devp->hd_name, (void *)devp)) {
 385                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 386                         irq = 0;
 387                 }
 388         }
 389
 390         if (irq == 0) {
 391                 spin_lock_irq(&hpet_lock);
 392                 devp->hd_flags ^= HPET_IE;
 393                 spin_unlock_irq(&hpet_lock);
 394                 return -EIO;
 395         }
 396
 397         devp->hd_irq = irq;
 398         t = devp->hd_ireqfreq;
 399         v = readq(&timer->hpet_config);
 400         g = v | Tn_INT_ENB_CNF_MASK;
 401
 402         if (devp->hd_flags & HPET_PERIODIC) {
 403                 write_counter(t, &timer->hpet_compare);
 404                 g |= Tn_TYPE_CNF_MASK;
 405                 v |= Tn_TYPE_CNF_MASK;
 406                 writeq(v, &timer->hpet_config);
 407                 v |= Tn_VAL_SET_CNF_MASK;
 408                 writeq(v, &timer->hpet_config);
 409                 local_irq_save(flags);
 410                 m = read_counter(&hpet->hpet_mc);
 411                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 412         } else {
 413                 local_irq_save(flags);
 414                 m = read_counter(&hpet->hpet_mc);
 415                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 416         }
 417
 418         isr = (1 << (devp - hpets->hp_dev));
 419         writeq(isr, &hpet->hpet_isr);
 420         writeq(g, &timer->hpet_config);
 421         local_irq_restore(flags);
 422
 423         return 0;
 424 }
 425
 426 static inline unsigned long hpet_time_div(unsigned long dis)
 427 {
 428         unsigned long long m = 1000000000000000ULL;
 429
 430         do_div(m, dis);
 431
 432         return (unsigned long)m;
 433 }
 434
 435 static int
 436 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
 437 {
 438         struct hpet_timer __iomem *timer;
 439         struct hpet __iomem *hpet;
 440         struct hpets *hpetp;
 441         int err;
 442         unsigned long v;
 443
 444         switch (cmd) {
 445         case HPET_IE_OFF:
 446         case HPET_INFO:
 447         case HPET_EPI:
 448         case HPET_DPI:
 449         case HPET_IRQFREQ:
 450                 timer = devp->hd_timer;
 451                 hpet = devp->hd_hpet;
 452                 hpetp = devp->hd_hpets;
 453                 break;
 454         case HPET_IE_ON:
 455                 return hpet_ioctl_ieon(devp);
 456         default:
 457                 return -EINVAL;
 458         }
 459
 460         err = 0;
 461
 462         switch (cmd) {
 463         case HPET_IE_OFF:
 464                 if ((devp->hd_flags & HPET_IE) == 0)
 465                         break;
 466                 v = readq(&timer->hpet_config);
 467                 v &= ~Tn_INT_ENB_CNF_MASK;
 468                 writeq(v, &timer->hpet_config);
 469                 if (devp->hd_irq) {
 470                         free_irq(devp->hd_irq, devp);
 471                         devp->hd_irq = 0;
 472                 }
 473                 devp->hd_flags ^= HPET_IE;
 474                 break;
 475         case HPET_INFO:
 476                 {
 477                         struct hpet_info info;
 478
 479                         info.hi_ireqfreq = hpet_time_div(hpetp->hp_period *
 480                                                          devp->hd_ireqfreq);
 481                         info.hi_flags =
 482                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 483                         info.hi_hpet = devp->hd_hpets->hp_which;
 484                         info.hi_timer = devp - devp->hd_hpets->hp_dev;
 485                         if (copy_to_user((void __user *)arg, &info, sizeof(info)))
 486                                 err = -EFAULT;
 487                         break;
 488                 }
 489         case HPET_EPI:
 490                 v = readq(&timer->hpet_config);
 491                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 492                         err = -ENXIO;
 493                         break;
 494                 }
 495                 devp->hd_flags |= HPET_PERIODIC;
 496                 break;
 497         case HPET_DPI:
 498                 v = readq(&timer->hpet_config);
 499                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 500                         err = -ENXIO;
 501                         break;
 502                 }
 503                 if (devp->hd_flags & HPET_PERIODIC &&
 504                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 505                         v = readq(&timer->hpet_config);
 506                         v ^= Tn_TYPE_CNF_MASK;
 507                         writeq(v, &timer->hpet_config);
 508                 }
 509                 devp->hd_flags &= ~HPET_PERIODIC;
 510                 break;
 511         case HPET_IRQFREQ:
 512                 if (!kernel && (arg > hpet_max_freq) &&
 513                     !capable(CAP_SYS_RESOURCE)) {
 514                         err = -EACCES;
 515                         break;
 516                 }
 517
 518                 if (arg & (arg - 1)) {
 519                         err = -EINVAL;
 520                         break;
 521                 }
 522
 523                 devp->hd_ireqfreq = hpet_time_div(hpetp->hp_period * arg);
 524         }
 525
 526         return err;
 527 }
 528
 529 static struct file_operations hpet_fops = {
 530         .owner = THIS_MODULE,
 531         .llseek = no_llseek,
 532         .read = hpet_read,
 533         .poll = hpet_poll,
 534         .ioctl = hpet_ioctl,
 535         .open = hpet_open,
 536         .release = hpet_release,
 537         .fasync = hpet_fasync,
 538         .mmap = hpet_mmap,
 539 };
 540
 541 EXPORT_SYMBOL(hpet_alloc);
 542 EXPORT_SYMBOL(hpet_register);
 543 EXPORT_SYMBOL(hpet_unregister);
 544 EXPORT_SYMBOL(hpet_control);
 545
 546 int hpet_register(struct hpet_task *tp, int periodic)
 547 {
 548         unsigned int i;
 549         u64 mask;
 550         struct hpet_timer __iomem *timer;
 551         struct hpet_dev *devp;
 552         struct hpets *hpetp;
 553
 554         switch (periodic) {
 555         case 1:
 556                 mask = Tn_PER_INT_CAP_MASK;
 557                 break;
 558         case 0:
 559                 mask = 0;
 560                 break;
 561         default:
 562                 return -EINVAL;
 563         }
 564
 565         spin_lock_irq(&hpet_task_lock);
 566         spin_lock(&hpet_lock);
 567
 568         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 569                 for (timer = hpetp->hp_hpet->hpet_timers, i = 0;
 570                      i < hpetp->hp_ntimer; i++, timer++) {
 571                         if ((readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK)
 572                             != mask)
 573                                 continue;
 574
 575                         devp = &hpetp->hp_dev[i];
 576
 577                         if (devp->hd_flags & HPET_OPEN || devp->hd_task) {
 578                                 devp = NULL;
 579                                 continue;
 580                         }
 581
 582                         tp->ht_opaque = devp;
 583                         devp->hd_task = tp;
 584                         break;
 585                 }
 586
 587         spin_unlock(&hpet_lock);
 588         spin_unlock_irq(&hpet_task_lock);
 589
 590         if (tp->ht_opaque)
 591                 return 0;
 592         else
 593                 return -EBUSY;
 594 }
 595
 596 static inline int hpet_tpcheck(struct hpet_task *tp)
 597 {
 598         struct hpet_dev *devp;
 599         struct hpets *hpetp;
 600
 601         devp = tp->ht_opaque;
 602
 603         if (!devp)
 604                 return -ENXIO;
 605
 606         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 607                 if (devp >= hpetp->hp_dev
 608                     && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
 609                     && devp->hd_hpet == hpetp->hp_hpet)
 610                         return 0;
 611
 612         return -ENXIO;
 613 }
 614
 615 int hpet_unregister(struct hpet_task *tp)
 616 {
 617         struct hpet_dev *devp;
 618         struct hpet_timer __iomem *timer;
 619         int err;
 620
 621         if ((err = hpet_tpcheck(tp)))
 622                 return err;
 623
 624         spin_lock_irq(&hpet_task_lock);
 625         spin_lock(&hpet_lock);
 626
 627         devp = tp->ht_opaque;
 628         if (devp->hd_task != tp) {
 629                 spin_unlock(&hpet_lock);
 630                 spin_unlock_irq(&hpet_task_lock);
 631                 return -ENXIO;
 632         }
 633
 634         timer = devp->hd_timer;
 635         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 636                &timer->hpet_config);
 637         devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
 638         devp->hd_task = NULL;
 639         spin_unlock(&hpet_lock);
 640         spin_unlock_irq(&hpet_task_lock);
 641
 642         return 0;
 643 }
 644
 645 int hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
 646 {
 647         struct hpet_dev *devp;
 648         int err;
 649
 650         if ((err = hpet_tpcheck(tp)))
 651                 return err;
 652
 653         spin_lock_irq(&hpet_lock);
 654         devp = tp->ht_opaque;
 655         if (devp->hd_task != tp) {
 656                 spin_unlock_irq(&hpet_lock);
 657                 return -ENXIO;
 658         }
 659         spin_unlock_irq(&hpet_lock);
 660         return hpet_ioctl_common(devp, cmd, arg, 1);
 661 }
 662
 663 #ifdef  CONFIG_TIME_INTERPOLATION
 664
 665 static struct time_interpolator hpet_interpolator = {
 666         .source = TIME_SOURCE_MMIO64,
 667         .shift = 10
 668 };
 669
 670 #endif
 671
 672 static ctl_table hpet_table[] = {
 673         {
 674          .ctl_name = 1,
 675          .procname = "max-user-freq",
 676          .data = &hpet_max_freq,
 677          .maxlen = sizeof(int),
 678          .mode = 0644,
 679          .proc_handler = &proc_dointvec,
 680          },
 681         {.ctl_name = 0}
 682 };
 683
 684 static ctl_table hpet_root[] = {
 685         {
 686          .ctl_name = 1,
 687          .procname = "hpet",
 688          .maxlen = 0,
 689          .mode = 0555,
 690          .child = hpet_table,
 691          },
 692         {.ctl_name = 0}
 693 };
 694
 695 static ctl_table dev_root[] = {
 696         {
 697          .ctl_name = CTL_DEV,
 698          .procname = "dev",
 699          .maxlen = 0,
 700          .mode = 0555,
 701          .child = hpet_root,
 702          },
 703         {.ctl_name = 0}
 704 };
 705
 706 static struct ctl_table_header *sysctl_header;
 707
 708 /*
 709  * Adjustment for when arming the timer with
 710  * initial conditions.  That is, main counter
 711  * ticks expired before interrupts are enabled.
 712  */
 713 #define TICK_CALIBRATE  (1000UL)
 714
 715 static unsigned long __init hpet_calibrate(struct hpets *hpetp)
 716 {
 717         struct hpet_timer __iomem *timer = NULL;
 718         unsigned long t, m, count, i, flags, start;
 719         struct hpet_dev *devp;
 720         int j;
 721         struct hpet __iomem *hpet;
 722
 723         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 724                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 725                         timer = devp->hd_timer;
 726                         break;
 727                 }
 728
 729         if (!timer)
 730                 return 0;
 731
 732         hpet = hpets->hp_hpet;
 733         t = read_counter(&timer->hpet_compare);
 734
 735         i = 0;
 736         count = hpet_time_div(hpetp->hp_period * TICK_CALIBRATE);
 737
 738         local_irq_save(flags);
 739
 740         start = read_counter(&hpet->hpet_mc);
 741
 742         do {
 743                 m = read_counter(&hpet->hpet_mc);
 744                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 745         } while (i++, (m - start) < count);
 746
 747         local_irq_restore(flags);
 748
 749         return (m - start) / i;
 750 }
 751
 752 int __init hpet_alloc(struct hpet_data *hdp)
 753 {
 754         u64 cap, mcfg;
 755         struct hpet_dev *devp;
 756         u32 i, ntimer;
 757         struct hpets *hpetp;
 758         size_t siz;
 759         struct hpet __iomem *hpet;
 760         static struct hpets *last __initdata = (struct hpets *)0;
 761         unsigned long ns;
 762
 763         /*
 764          * hpet_alloc can be called by platform dependent code.
 765          * if platform dependent code has allocated the hpet
 766          * ACPI also reports hpet, then we catch it here.
 767          */
 768         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 769                 if (hpetp->hp_hpet == hdp->hd_address)
 770                         return 0;
 771
 772         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 773                                       sizeof(struct hpet_dev));
 774
 775         hpetp = kmalloc(siz, GFP_KERNEL);
 776
 777         if (!hpetp)
 778                 return -ENOMEM;
 779
 780         memset(hpetp, 0, siz);
 781
 782         hpetp->hp_which = hpet_nhpet++;
 783         hpetp->hp_hpet = hdp->hd_address;
 784
 785         hpetp->hp_ntimer = hdp->hd_nirqs;
 786
 787         for (i = 0; i < hdp->hd_nirqs; i++)
 788                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 789
 790         hpet = hpetp->hp_hpet;
 791
 792         cap = readq(&hpet->hpet_cap);
 793
 794         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 795
 796         if (hpetp->hp_ntimer != ntimer) {
 797                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 798                        " with number of timers\n");
 799                 kfree(hpetp);
 800                 return -ENODEV;
 801         }
 802
 803         if (last)
 804                 last->hp_next = hpetp;
 805         else
 806                 hpets = hpetp;
 807
 808         last = hpetp;
 809
 810         hpetp->hp_period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 811             HPET_COUNTER_CLK_PERIOD_SHIFT;
 812
 813         printk(KERN_INFO "hpet%d: at MMIO 0x%p, IRQ%s",
 814                 hpetp->hp_which, hpet, hpetp->hp_ntimer > 1 ? "s" : "");
 815         for (i = 0; i < hpetp->hp_ntimer; i++)
 816                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 817         printk("\n");
 818
 819         ns = hpetp->hp_period;  /* femptoseconds, 10^-15 */
 820         do_div(ns, 1000000);    /* convert to nanoseconds, 10^-9 */
 821         printk(KERN_INFO "hpet%d: %ldns tick, %d %d-bit timers\n",
 822                 hpetp->hp_which, ns, hpetp->hp_ntimer,
 823                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32);
 824
 825         mcfg = readq(&hpet->hpet_config);
 826         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 827                 write_counter(0L, &hpet->hpet_mc);
 828                 mcfg |= HPET_ENABLE_CNF_MASK;
 829                 writeq(mcfg, &hpet->hpet_config);
 830         }
 831
 832         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer;
 833              i++, hpet_ntimer++, devp++) {
 834                 unsigned long v;
 835                 struct hpet_timer __iomem *timer;
 836
 837                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 838                 v = readq(&timer->hpet_config);
 839
 840                 devp->hd_hpets = hpetp;
 841                 devp->hd_hpet = hpet;
 842                 devp->hd_timer = timer;
 843
 844                 /*
 845                  * If the timer was reserved by platform code,
 846                  * then make timer unavailable for opens.
 847                  */
 848                 if (hdp->hd_state & (1 << i)) {
 849                         devp->hd_flags = HPET_OPEN;
 850                         continue;
 851                 }
 852
 853                 init_waitqueue_head(&devp->hd_waitqueue);
 854         }
 855
 856         hpetp->hp_delta = hpet_calibrate(hpetp);
 857
 858         return 0;
 859 }
 860
 861 static acpi_status __init hpet_resources(struct acpi_resource *res, void *data)
 862 {
 863         struct hpet_data *hdp;
 864         acpi_status status;
 865         struct acpi_resource_address64 addr;
 866         struct hpets *hpetp;
 867
 868         hdp = data;
 869
 870         status = acpi_resource_to_address64(res, &addr);
 871
 872         if (ACPI_SUCCESS(status)) {
 873                 unsigned long size;
 874
 875                 size = addr.max_address_range - addr.min_address_range + 1;
 876                 hdp->hd_address = ioremap(addr.min_address_range, size);
 877
 878                 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 879                         if (hpetp->hp_hpet == hdp->hd_address)
 880                                 return -EBUSY;
 881         } else if (res->id == ACPI_RSTYPE_EXT_IRQ) {
 882                 struct acpi_resource_ext_irq *irqp;
 883                 int i;
 884
 885                 irqp = &res->data.extended_irq;
 886
 887                 if (irqp->number_of_interrupts > 0) {
 888                         hdp->hd_nirqs = irqp->number_of_interrupts;
 889
 890                         for (i = 0; i < hdp->hd_nirqs; i++)
 891                                 hdp->hd_irq[i] =
 892                                     acpi_register_gsi(irqp->interrupts[i],
 893                                                       irqp->edge_level,
 894                                                       irqp->active_high_low);
 895                 }
 896         }
 897
 898         return AE_OK;
 899 }
 900
 901 static int __init hpet_acpi_add(struct acpi_device *device)
 902 {
 903         acpi_status result;
 904         struct hpet_data data;
 905
 906         memset(&data, 0, sizeof(data));
 907
 908         result =
 909             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 910                                 hpet_resources, &data);
 911
 912         if (ACPI_FAILURE(result))
 913                 return -ENODEV;
 914
 915         if (!data.hd_address || !data.hd_nirqs) {
 916                 printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
 917                 return -ENODEV;
 918         }
 919
 920         return hpet_alloc(&data);
 921 }
 922
 923 static int __init hpet_acpi_remove(struct acpi_device *device, int type)
 924 {
 925         return 0;
 926 }
 927
 928 static struct acpi_driver hpet_acpi_driver = {
 929         .name = "hpet",
 930         .ids = "PNP0103",
 931         .ops = {
 932                 .add = hpet_acpi_add,
 933                 .remove = hpet_acpi_remove,
 934                 },
 935 };
 936
 937 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
 938
 939 static int __init hpet_init(void)
 940 {
 941         (void)acpi_bus_register_driver(&hpet_acpi_driver);
 942
 943         if (hpets) {
 944                 if (misc_register(&hpet_misc))
 945                         return -ENODEV;
 946
 947                 sysctl_header = register_sysctl_table(dev_root, 0);
 948
 949 #ifdef  CONFIG_TIME_INTERPOLATION
 950                 {
 951                         struct hpet *hpet;
 952
 953                         hpet = hpets->hp_hpet;
 954                         hpet_interpolator.addr = &hpets->hp_hpet->hpet_mc;
 955                         hpet_interpolator.frequency = hpet_time_div(hpets->hp_period);
 956                         hpet_interpolator.drift = hpet_interpolator.frequency *
 957                             HPET_DRIFT / 1000000;
 958                         register_time_interpolator(&hpet_interpolator);
 959                 }
 960 #endif
 961                 return 0;
 962         } else
 963                 return -ENODEV;
 964 }
 965
 966 static void __exit hpet_exit(void)
 967 {
 968         acpi_bus_unregister_driver(&hpet_acpi_driver);
 969
 970         if (hpets)
 971                 unregister_sysctl_table(sysctl_header);
 972
 973         return;
 974 }
 975
 976 module_init(hpet_init);
 977 module_exit(hpet_exit);
 978 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
 979 MODULE_LICENSE("GPL");