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/smp_lock.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/mm.h>
  26 #include <linux/proc_fs.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/sysctl.h>
  29 #include <linux/wait.h>
  30 #include <linux/bcd.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/bitops.h>
  33 #include <linux/clocksource.h>
  34
  35 #include <asm/current.h>
  36 #include <asm/uaccess.h>
  37 #include <asm/system.h>
  38 #include <asm/io.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.htm
  50  */
  51 #define HPET_USER_FREQ  (64)
  52 #define HPET_DRIFT      (500)
  53
  54 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
  55
  56 #if BITS_PER_LONG == 64
  57 #define write_counter(V, MC)    writeq(V, MC)
  58 #define read_counter(MC)        readq(MC)
  59 #else
  60 #define write_counter(V, MC)    writel(V, MC)
  61 #define read_counter(MC)        readl(MC)
  62 #endif
  63
  64 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  65
  66 /* This clocksource driver currently only works on ia64 */
  67 #ifdef CONFIG_IA64
  68 static void __iomem *hpet_mctr;
  69
  70 static cycle_t read_hpet(void)
  71 {
  72         return (cycle_t)read_counter((void __iomem *)hpet_mctr);
  73 }
  74
  75 static struct clocksource clocksource_hpet = {
  76         .name           = "hpet",
  77         .rating         = 250,
  78         .read           = read_hpet,
  79         .mask           = CLOCKSOURCE_MASK(64),
  80         .mult           = 0, /*to be caluclated*/
  81         .shift          = 10,
  82         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  83 };
  84 static struct clocksource *hpet_clocksource;
  85 #endif
  86
  87 /* A lock for concurrent access by app and isr hpet activity. */
  88 static DEFINE_SPINLOCK(hpet_lock);
  89 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
  90 static DEFINE_SPINLOCK(hpet_task_lock);
  91
  92 #define HPET_DEV_NAME   (7)
  93
  94 struct hpet_dev {
  95         struct hpets *hd_hpets;
  96         struct hpet __iomem *hd_hpet;
  97         struct hpet_timer __iomem *hd_timer;
  98         unsigned long hd_ireqfreq;
  99         unsigned long hd_irqdata;
 100         wait_queue_head_t hd_waitqueue;
 101         struct fasync_struct *hd_async_queue;
 102         struct hpet_task *hd_task;
 103         unsigned int hd_flags;
 104         unsigned int hd_irq;
 105         unsigned int hd_hdwirq;
 106         char hd_name[HPET_DEV_NAME];
 107 };
 108
 109 struct hpets {
 110         struct hpets *hp_next;
 111         struct hpet __iomem *hp_hpet;
 112         unsigned long hp_hpet_phys;
 113         struct clocksource *hp_clocksource;
 114         unsigned long long hp_tick_freq;
 115         unsigned long hp_delta;
 116         unsigned int hp_ntimer;
 117         unsigned int hp_which;
 118         struct hpet_dev hp_dev[1];
 119 };
 120
 121 static struct hpets *hpets;
 122
 123 #define HPET_OPEN               0x0001
 124 #define HPET_IE                 0x0002  /* interrupt enabled */
 125 #define HPET_PERIODIC           0x0004
 126 #define HPET_SHARED_IRQ         0x0008
 127
 128
 129 #ifndef readq
 130 static inline unsigned long long readq(void __iomem *addr)
 131 {
 132         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 133 }
 134 #endif
 135
 136 #ifndef writeq
 137 static inline void writeq(unsigned long long v, void __iomem *addr)
 138 {
 139         writel(v & 0xffffffff, addr);
 140         writel(v >> 32, addr + 4);
 141 }
 142 #endif
 143
 144 static irqreturn_t hpet_interrupt(int irq, void *data)
 145 {
 146         struct hpet_dev *devp;
 147         unsigned long isr;
 148
 149         devp = data;
 150         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 151
 152         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 153             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 154                 return IRQ_NONE;
 155
 156         spin_lock(&hpet_lock);
 157         devp->hd_irqdata++;
 158
 159         /*
 160          * For non-periodic timers, increment the accumulator.
 161          * This has the effect of treating non-periodic like periodic.
 162          */
 163         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 164                 unsigned long m, t;
 165
 166                 t = devp->hd_ireqfreq;
 167                 m = read_counter(&devp->hd_hpet->hpet_mc);
 168                 write_counter(t + m + devp->hd_hpets->hp_delta,
 169                               &devp->hd_timer->hpet_compare);
 170         }
 171
 172         if (devp->hd_flags & HPET_SHARED_IRQ)
 173                 writel(isr, &devp->hd_hpet->hpet_isr);
 174         spin_unlock(&hpet_lock);
 175
 176         spin_lock(&hpet_task_lock);
 177         if (devp->hd_task)
 178                 devp->hd_task->ht_func(devp->hd_task->ht_data);
 179         spin_unlock(&hpet_task_lock);
 180
 181         wake_up_interruptible(&devp->hd_waitqueue);
 182
 183         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 184
 185         return IRQ_HANDLED;
 186 }
 187
 188 static int hpet_open(struct inode *inode, struct file *file)
 189 {
 190         struct hpet_dev *devp;
 191         struct hpets *hpetp;
 192         int i;
 193
 194         if (file->f_mode & FMODE_WRITE)
 195                 return -EINVAL;
 196
 197         lock_kernel();
 198         spin_lock_irq(&hpet_lock);
 199
 200         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 201                 for (i = 0; i < hpetp->hp_ntimer; i++)
 202                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
 203                             || hpetp->hp_dev[i].hd_task)
 204                                 continue;
 205                         else {
 206                                 devp = &hpetp->hp_dev[i];
 207                                 break;
 208                         }
 209
 210         if (!devp) {
 211                 spin_unlock_irq(&hpet_lock);
 212                 unlock_kernel();
 213                 return -EBUSY;
 214         }
 215
 216         file->private_data = devp;
 217         devp->hd_irqdata = 0;
 218         devp->hd_flags |= HPET_OPEN;
 219         spin_unlock_irq(&hpet_lock);
 220         unlock_kernel();
 221
 222         return 0;
 223 }
 224
 225 static ssize_t
 226 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 227 {
 228         DECLARE_WAITQUEUE(wait, current);
 229         unsigned long data;
 230         ssize_t retval;
 231         struct hpet_dev *devp;
 232
 233         devp = file->private_data;
 234         if (!devp->hd_ireqfreq)
 235                 return -EIO;
 236
 237         if (count < sizeof(unsigned long))
 238                 return -EINVAL;
 239
 240         add_wait_queue(&devp->hd_waitqueue, &wait);
 241
 242         for ( ; ; ) {
 243                 set_current_state(TASK_INTERRUPTIBLE);
 244
 245                 spin_lock_irq(&hpet_lock);
 246                 data = devp->hd_irqdata;
 247                 devp->hd_irqdata = 0;
 248                 spin_unlock_irq(&hpet_lock);
 249
 250                 if (data)
 251                         break;
 252                 else if (file->f_flags & O_NONBLOCK) {
 253                         retval = -EAGAIN;
 254                         goto out;
 255                 } else if (signal_pending(current)) {
 256                         retval = -ERESTARTSYS;
 257                         goto out;
 258                 }
 259                 schedule();
 260         }
 261
 262         retval = put_user(data, (unsigned long __user *)buf);
 263         if (!retval)
 264                 retval = sizeof(unsigned long);
 265 out:
 266         __set_current_state(TASK_RUNNING);
 267         remove_wait_queue(&devp->hd_waitqueue, &wait);
 268
 269         return retval;
 270 }
 271
 272 static unsigned int hpet_poll(struct file *file, poll_table * wait)
 273 {
 274         unsigned long v;
 275         struct hpet_dev *devp;
 276
 277         devp = file->private_data;
 278
 279         if (!devp->hd_ireqfreq)
 280                 return 0;
 281
 282         poll_wait(file, &devp->hd_waitqueue, wait);
 283
 284         spin_lock_irq(&hpet_lock);
 285         v = devp->hd_irqdata;
 286         spin_unlock_irq(&hpet_lock);
 287
 288         if (v != 0)
 289                 return POLLIN | POLLRDNORM;
 290
 291         return 0;
 292 }
 293
 294 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 295 {
 296 #ifdef  CONFIG_HPET_MMAP
 297         struct hpet_dev *devp;
 298         unsigned long addr;
 299
 300         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
 301                 return -EINVAL;
 302
 303         devp = file->private_data;
 304         addr = devp->hd_hpets->hp_hpet_phys;
 305
 306         if (addr & (PAGE_SIZE - 1))
 307                 return -ENOSYS;
 308
 309         vma->vm_flags |= VM_IO;
 310         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 311
 312         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
 313                                         PAGE_SIZE, vma->vm_page_prot)) {
 314                 printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
 315                         __func__);
 316                 return -EAGAIN;
 317         }
 318
 319         return 0;
 320 #else
 321         return -ENOSYS;
 322 #endif
 323 }
 324
 325 static int hpet_fasync(int fd, struct file *file, int on)
 326 {
 327         struct hpet_dev *devp;
 328
 329         devp = file->private_data;
 330
 331         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 332                 return 0;
 333         else
 334                 return -EIO;
 335 }
 336
 337 static int hpet_release(struct inode *inode, struct file *file)
 338 {
 339         struct hpet_dev *devp;
 340         struct hpet_timer __iomem *timer;
 341         int irq = 0;
 342
 343         devp = file->private_data;
 344         timer = devp->hd_timer;
 345
 346         spin_lock_irq(&hpet_lock);
 347
 348         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 349                &timer->hpet_config);
 350
 351         irq = devp->hd_irq;
 352         devp->hd_irq = 0;
 353
 354         devp->hd_ireqfreq = 0;
 355
 356         if (devp->hd_flags & HPET_PERIODIC
 357             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 358                 unsigned long v;
 359
 360                 v = readq(&timer->hpet_config);
 361                 v ^= Tn_TYPE_CNF_MASK;
 362                 writeq(v, &timer->hpet_config);
 363         }
 364
 365         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 366         spin_unlock_irq(&hpet_lock);
 367
 368         if (irq)
 369                 free_irq(irq, devp);
 370
 371         if (file->f_flags & FASYNC)
 372                 hpet_fasync(-1, file, 0);
 373
 374         file->private_data = NULL;
 375         return 0;
 376 }
 377
 378 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
 379
 380 static int
 381 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 382            unsigned long arg)
 383 {
 384         struct hpet_dev *devp;
 385
 386         devp = file->private_data;
 387         return hpet_ioctl_common(devp, cmd, arg, 0);
 388 }
 389
 390 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 391 {
 392         struct hpet_timer __iomem *timer;
 393         struct hpet __iomem *hpet;
 394         struct hpets *hpetp;
 395         int irq;
 396         unsigned long g, v, t, m;
 397         unsigned long flags, isr;
 398
 399         timer = devp->hd_timer;
 400         hpet = devp->hd_hpet;
 401         hpetp = devp->hd_hpets;
 402
 403         if (!devp->hd_ireqfreq)
 404                 return -EIO;
 405
 406         spin_lock_irq(&hpet_lock);
 407
 408         if (devp->hd_flags & HPET_IE) {
 409                 spin_unlock_irq(&hpet_lock);
 410                 return -EBUSY;
 411         }
 412
 413         devp->hd_flags |= HPET_IE;
 414
 415         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 416                 devp->hd_flags |= HPET_SHARED_IRQ;
 417         spin_unlock_irq(&hpet_lock);
 418
 419         irq = devp->hd_hdwirq;
 420
 421         if (irq) {
 422                 unsigned long irq_flags;
 423
 424                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 425                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 426                                                 ? IRQF_SHARED : IRQF_DISABLED;
 427                 if (request_irq(irq, hpet_interrupt, irq_flags,
 428                                 devp->hd_name, (void *)devp)) {
 429                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 430                         irq = 0;
 431                 }
 432         }
 433
 434         if (irq == 0) {
 435                 spin_lock_irq(&hpet_lock);
 436                 devp->hd_flags ^= HPET_IE;
 437                 spin_unlock_irq(&hpet_lock);
 438                 return -EIO;
 439         }
 440
 441         devp->hd_irq = irq;
 442         t = devp->hd_ireqfreq;
 443         v = readq(&timer->hpet_config);
 444         g = v | Tn_INT_ENB_CNF_MASK;
 445
 446         if (devp->hd_flags & HPET_PERIODIC) {
 447                 write_counter(t, &timer->hpet_compare);
 448                 g |= Tn_TYPE_CNF_MASK;
 449                 v |= Tn_TYPE_CNF_MASK;
 450                 writeq(v, &timer->hpet_config);
 451                 v |= Tn_VAL_SET_CNF_MASK;
 452                 writeq(v, &timer->hpet_config);
 453                 local_irq_save(flags);
 454                 m = read_counter(&hpet->hpet_mc);
 455                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 456         } else {
 457                 local_irq_save(flags);
 458                 m = read_counter(&hpet->hpet_mc);
 459                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 460         }
 461
 462         if (devp->hd_flags & HPET_SHARED_IRQ) {
 463                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 464                 writel(isr, &hpet->hpet_isr);
 465         }
 466         writeq(g, &timer->hpet_config);
 467         local_irq_restore(flags);
 468
 469         return 0;
 470 }
 471
 472 /* converts Hz to number of timer ticks */
 473 static inline unsigned long hpet_time_div(struct hpets *hpets,
 474                                           unsigned long dis)
 475 {
 476         unsigned long long m;
 477
 478         m = hpets->hp_tick_freq + (dis >> 1);
 479         do_div(m, dis);
 480         return (unsigned long)m;
 481 }
 482
 483 static int
 484 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
 485 {
 486         struct hpet_timer __iomem *timer;
 487         struct hpet __iomem *hpet;
 488         struct hpets *hpetp;
 489         int err;
 490         unsigned long v;
 491
 492         switch (cmd) {
 493         case HPET_IE_OFF:
 494         case HPET_INFO:
 495         case HPET_EPI:
 496         case HPET_DPI:
 497         case HPET_IRQFREQ:
 498                 timer = devp->hd_timer;
 499                 hpet = devp->hd_hpet;
 500                 hpetp = devp->hd_hpets;
 501                 break;
 502         case HPET_IE_ON:
 503                 return hpet_ioctl_ieon(devp);
 504         default:
 505                 return -EINVAL;
 506         }
 507
 508         err = 0;
 509
 510         switch (cmd) {
 511         case HPET_IE_OFF:
 512                 if ((devp->hd_flags & HPET_IE) == 0)
 513                         break;
 514                 v = readq(&timer->hpet_config);
 515                 v &= ~Tn_INT_ENB_CNF_MASK;
 516                 writeq(v, &timer->hpet_config);
 517                 if (devp->hd_irq) {
 518                         free_irq(devp->hd_irq, devp);
 519                         devp->hd_irq = 0;
 520                 }
 521                 devp->hd_flags ^= HPET_IE;
 522                 break;
 523         case HPET_INFO:
 524                 {
 525                         struct hpet_info info;
 526
 527                         if (devp->hd_ireqfreq)
 528                                 info.hi_ireqfreq =
 529                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 530                         else
 531                                 info.hi_ireqfreq = 0;
 532                         info.hi_flags =
 533                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 534                         info.hi_hpet = hpetp->hp_which;
 535                         info.hi_timer = devp - hpetp->hp_dev;
 536                         if (kernel)
 537                                 memcpy((void *)arg, &info, sizeof(info));
 538                         else
 539                                 if (copy_to_user((void __user *)arg, &info,
 540                                                  sizeof(info)))
 541                                         err = -EFAULT;
 542                         break;
 543                 }
 544         case HPET_EPI:
 545                 v = readq(&timer->hpet_config);
 546                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 547                         err = -ENXIO;
 548                         break;
 549                 }
 550                 devp->hd_flags |= HPET_PERIODIC;
 551                 break;
 552         case HPET_DPI:
 553                 v = readq(&timer->hpet_config);
 554                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 555                         err = -ENXIO;
 556                         break;
 557                 }
 558                 if (devp->hd_flags & HPET_PERIODIC &&
 559                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 560                         v = readq(&timer->hpet_config);
 561                         v ^= Tn_TYPE_CNF_MASK;
 562                         writeq(v, &timer->hpet_config);
 563                 }
 564                 devp->hd_flags &= ~HPET_PERIODIC;
 565                 break;
 566         case HPET_IRQFREQ:
 567                 if (!kernel && (arg > hpet_max_freq) &&
 568                     !capable(CAP_SYS_RESOURCE)) {
 569                         err = -EACCES;
 570                         break;
 571                 }
 572
 573                 if (!arg) {
 574                         err = -EINVAL;
 575                         break;
 576                 }
 577
 578                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 579         }
 580
 581         return err;
 582 }
 583
 584 static const struct file_operations hpet_fops = {
 585         .owner = THIS_MODULE,
 586         .llseek = no_llseek,
 587         .read = hpet_read,
 588         .poll = hpet_poll,
 589         .ioctl = hpet_ioctl,
 590         .open = hpet_open,
 591         .release = hpet_release,
 592         .fasync = hpet_fasync,
 593         .mmap = hpet_mmap,
 594 };
 595
 596 static int hpet_is_known(struct hpet_data *hdp)
 597 {
 598         struct hpets *hpetp;
 599
 600         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 601                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 602                         return 1;
 603
 604         return 0;
 605 }
 606
 607 static inline int hpet_tpcheck(struct hpet_task *tp)
 608 {
 609         struct hpet_dev *devp;
 610         struct hpets *hpetp;
 611
 612         devp = tp->ht_opaque;
 613
 614         if (!devp)
 615                 return -ENXIO;
 616
 617         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 618                 if (devp >= hpetp->hp_dev
 619                     && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
 620                     && devp->hd_hpet == hpetp->hp_hpet)
 621                         return 0;
 622
 623         return -ENXIO;
 624 }
 625
 626 int hpet_unregister(struct hpet_task *tp)
 627 {
 628         struct hpet_dev *devp;
 629         struct hpet_timer __iomem *timer;
 630         int err;
 631
 632         if ((err = hpet_tpcheck(tp)))
 633                 return err;
 634
 635         spin_lock_irq(&hpet_task_lock);
 636         spin_lock(&hpet_lock);
 637
 638         devp = tp->ht_opaque;
 639         if (devp->hd_task != tp) {
 640                 spin_unlock(&hpet_lock);
 641                 spin_unlock_irq(&hpet_task_lock);
 642                 return -ENXIO;
 643         }
 644
 645         timer = devp->hd_timer;
 646         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 647                &timer->hpet_config);
 648         devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
 649         devp->hd_task = NULL;
 650         spin_unlock(&hpet_lock);
 651         spin_unlock_irq(&hpet_task_lock);
 652
 653         return 0;
 654 }
 655
 656 static ctl_table hpet_table[] = {
 657         {
 658          .ctl_name = CTL_UNNUMBERED,
 659          .procname = "max-user-freq",
 660          .data = &hpet_max_freq,
 661          .maxlen = sizeof(int),
 662          .mode = 0644,
 663          .proc_handler = &proc_dointvec,
 664          },
 665         {.ctl_name = 0}
 666 };
 667
 668 static ctl_table hpet_root[] = {
 669         {
 670          .ctl_name = CTL_UNNUMBERED,
 671          .procname = "hpet",
 672          .maxlen = 0,
 673          .mode = 0555,
 674          .child = hpet_table,
 675          },
 676         {.ctl_name = 0}
 677 };
 678
 679 static ctl_table dev_root[] = {
 680         {
 681          .ctl_name = CTL_DEV,
 682          .procname = "dev",
 683          .maxlen = 0,
 684          .mode = 0555,
 685          .child = hpet_root,
 686          },
 687         {.ctl_name = 0}
 688 };
 689
 690 static struct ctl_table_header *sysctl_header;
 691
 692 /*
 693  * Adjustment for when arming the timer with
 694  * initial conditions.  That is, main counter
 695  * ticks expired before interrupts are enabled.
 696  */
 697 #define TICK_CALIBRATE  (1000UL)
 698
 699 static unsigned long hpet_calibrate(struct hpets *hpetp)
 700 {
 701         struct hpet_timer __iomem *timer = NULL;
 702         unsigned long t, m, count, i, flags, start;
 703         struct hpet_dev *devp;
 704         int j;
 705         struct hpet __iomem *hpet;
 706
 707         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 708                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 709                         timer = devp->hd_timer;
 710                         break;
 711                 }
 712
 713         if (!timer)
 714                 return 0;
 715
 716         hpet = hpetp->hp_hpet;
 717         t = read_counter(&timer->hpet_compare);
 718
 719         i = 0;
 720         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 721
 722         local_irq_save(flags);
 723
 724         start = read_counter(&hpet->hpet_mc);
 725
 726         do {
 727                 m = read_counter(&hpet->hpet_mc);
 728                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 729         } while (i++, (m - start) < count);
 730
 731         local_irq_restore(flags);
 732
 733         return (m - start) / i;
 734 }
 735
 736 int hpet_alloc(struct hpet_data *hdp)
 737 {
 738         u64 cap, mcfg;
 739         struct hpet_dev *devp;
 740         u32 i, ntimer;
 741         struct hpets *hpetp;
 742         size_t siz;
 743         struct hpet __iomem *hpet;
 744         static struct hpets *last = NULL;
 745         unsigned long period;
 746         unsigned long long temp;
 747
 748         /*
 749          * hpet_alloc can be called by platform dependent code.
 750          * If platform dependent code has allocated the hpet that
 751          * ACPI has also reported, then we catch it here.
 752          */
 753         if (hpet_is_known(hdp)) {
 754                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 755                         __func__);
 756                 return 0;
 757         }
 758
 759         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 760                                       sizeof(struct hpet_dev));
 761
 762         hpetp = kzalloc(siz, GFP_KERNEL);
 763
 764         if (!hpetp)
 765                 return -ENOMEM;
 766
 767         hpetp->hp_which = hpet_nhpet++;
 768         hpetp->hp_hpet = hdp->hd_address;
 769         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 770
 771         hpetp->hp_ntimer = hdp->hd_nirqs;
 772
 773         for (i = 0; i < hdp->hd_nirqs; i++)
 774                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 775
 776         hpet = hpetp->hp_hpet;
 777
 778         cap = readq(&hpet->hpet_cap);
 779
 780         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 781
 782         if (hpetp->hp_ntimer != ntimer) {
 783                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 784                        " with number of timers\n");
 785                 kfree(hpetp);
 786                 return -ENODEV;
 787         }
 788
 789         if (last)
 790                 last->hp_next = hpetp;
 791         else
 792                 hpets = hpetp;
 793
 794         last = hpetp;
 795
 796         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 797                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 798         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 799         temp += period >> 1; /* round */
 800         do_div(temp, period);
 801         hpetp->hp_tick_freq = temp; /* ticks per second */
 802
 803         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 804                 hpetp->hp_which, hdp->hd_phys_address,
 805                 hpetp->hp_ntimer > 1 ? "s" : "");
 806         for (i = 0; i < hpetp->hp_ntimer; i++)
 807                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 808         printk("\n");
 809
 810         printk(KERN_INFO "hpet%u: %u %d-bit timers, %Lu Hz\n",
 811                hpetp->hp_which, hpetp->hp_ntimer,
 812                cap & HPET_COUNTER_SIZE_MASK ? 64 : 32, hpetp->hp_tick_freq);
 813
 814         mcfg = readq(&hpet->hpet_config);
 815         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 816                 write_counter(0L, &hpet->hpet_mc);
 817                 mcfg |= HPET_ENABLE_CNF_MASK;
 818                 writeq(mcfg, &hpet->hpet_config);
 819         }
 820
 821         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 822                 struct hpet_timer __iomem *timer;
 823
 824                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 825
 826                 devp->hd_hpets = hpetp;
 827                 devp->hd_hpet = hpet;
 828                 devp->hd_timer = timer;
 829
 830                 /*
 831                  * If the timer was reserved by platform code,
 832                  * then make timer unavailable for opens.
 833                  */
 834                 if (hdp->hd_state & (1 << i)) {
 835                         devp->hd_flags = HPET_OPEN;
 836                         continue;
 837                 }
 838
 839                 init_waitqueue_head(&devp->hd_waitqueue);
 840         }
 841
 842         hpetp->hp_delta = hpet_calibrate(hpetp);
 843
 844 /* This clocksource driver currently only works on ia64 */
 845 #ifdef CONFIG_IA64
 846         if (!hpet_clocksource) {
 847                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 848                 CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
 849                 clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
 850                                                 clocksource_hpet.shift);
 851                 clocksource_register(&clocksource_hpet);
 852                 hpetp->hp_clocksource = &clocksource_hpet;
 853                 hpet_clocksource = &clocksource_hpet;
 854         }
 855 #endif
 856
 857         return 0;
 858 }
 859
 860 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 861 {
 862         struct hpet_data *hdp;
 863         acpi_status status;
 864         struct acpi_resource_address64 addr;
 865
 866         hdp = data;
 867
 868         status = acpi_resource_to_address64(res, &addr);
 869
 870         if (ACPI_SUCCESS(status)) {
 871                 hdp->hd_phys_address = addr.minimum;
 872                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 873
 874                 if (hpet_is_known(hdp)) {
 875                         printk(KERN_DEBUG "%s: 0x%lx is busy\n",
 876                                 __func__, hdp->hd_phys_address);
 877                         iounmap(hdp->hd_address);
 878                         return AE_ALREADY_EXISTS;
 879                 }
 880         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 881                 struct acpi_resource_fixed_memory32 *fixmem32;
 882
 883                 fixmem32 = &res->data.fixed_memory32;
 884                 if (!fixmem32)
 885                         return AE_NO_MEMORY;
 886
 887                 hdp->hd_phys_address = fixmem32->address;
 888                 hdp->hd_address = ioremap(fixmem32->address,
 889                                                 HPET_RANGE_SIZE);
 890
 891                 if (hpet_is_known(hdp)) {
 892                         printk(KERN_DEBUG "%s: 0x%lx is busy\n",
 893                                 __func__, hdp->hd_phys_address);
 894                         iounmap(hdp->hd_address);
 895                         return AE_ALREADY_EXISTS;
 896                 }
 897         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 898                 struct acpi_resource_extended_irq *irqp;
 899                 int i, irq;
 900
 901                 irqp = &res->data.extended_irq;
 902
 903                 for (i = 0; i < irqp->interrupt_count; i++) {
 904                         irq = acpi_register_gsi(irqp->interrupts[i],
 905                                       irqp->triggering, irqp->polarity);
 906                         if (irq < 0)
 907                                 return AE_ERROR;
 908
 909                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 910                         hdp->hd_nirqs++;
 911                 }
 912         }
 913
 914         return AE_OK;
 915 }
 916
 917 static int hpet_acpi_add(struct acpi_device *device)
 918 {
 919         acpi_status result;
 920         struct hpet_data data;
 921
 922         memset(&data, 0, sizeof(data));
 923
 924         result =
 925             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 926                                 hpet_resources, &data);
 927
 928         if (ACPI_FAILURE(result))
 929                 return -ENODEV;
 930
 931         if (!data.hd_address || !data.hd_nirqs) {
 932                 printk("%s: no address or irqs in _CRS\n", __func__);
 933                 return -ENODEV;
 934         }
 935
 936         return hpet_alloc(&data);
 937 }
 938
 939 static int hpet_acpi_remove(struct acpi_device *device, int type)
 940 {
 941         /* XXX need to unregister clocksource, dealloc mem, etc */
 942         return -EINVAL;
 943 }
 944
 945 static const struct acpi_device_id hpet_device_ids[] = {
 946         {"PNP0103", 0},
 947         {"", 0},
 948 };
 949 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
 950
 951 static struct acpi_driver hpet_acpi_driver = {
 952         .name = "hpet",
 953         .ids = hpet_device_ids,
 954         .ops = {
 955                 .add = hpet_acpi_add,
 956                 .remove = hpet_acpi_remove,
 957                 },
 958 };
 959
 960 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
 961
 962 static int __init hpet_init(void)
 963 {
 964         int result;
 965
 966         result = misc_register(&hpet_misc);
 967         if (result < 0)
 968                 return -ENODEV;
 969
 970         sysctl_header = register_sysctl_table(dev_root);
 971
 972         result = acpi_bus_register_driver(&hpet_acpi_driver);
 973         if (result < 0) {
 974                 if (sysctl_header)
 975                         unregister_sysctl_table(sysctl_header);
 976                 misc_deregister(&hpet_misc);
 977                 return result;
 978         }
 979
 980         return 0;
 981 }
 982
 983 static void __exit hpet_exit(void)
 984 {
 985         acpi_bus_unregister_driver(&hpet_acpi_driver);
 986
 987         if (sysctl_header)
 988                 unregister_sysctl_table(sysctl_header);
 989         misc_deregister(&hpet_misc);
 990
 991         return;
 992 }
 993
 994 module_init(hpet_init);
 995 module_exit(hpet_exit);
 996 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
 997 MODULE_LICENSE("GPL");