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_1.pdf
  50  */
  51 #define HPET_USER_FREQ  (64)
  52 #define HPET_DRIFT      (500)
  53
  54 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
  55
  56
  57 /* WARNING -- don't get confused.  These macros are never used
  58  * to write the (single) counter, and rarely to read it.
  59  * They're badly named; to fix, someday.
  60  */
  61 #if BITS_PER_LONG == 64
  62 #define write_counter(V, MC)    writeq(V, MC)
  63 #define read_counter(MC)        readq(MC)
  64 #else
  65 #define write_counter(V, MC)    writel(V, MC)
  66 #define read_counter(MC)        readl(MC)
  67 #endif
  68
  69 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  70
  71 /* This clocksource driver currently only works on ia64 */
  72 #ifdef CONFIG_IA64
  73 static void __iomem *hpet_mctr;
  74
  75 static cycle_t read_hpet(struct clocksource *cs)
  76 {
  77         return (cycle_t)read_counter((void __iomem *)hpet_mctr);
  78 }
  79
  80 static struct clocksource clocksource_hpet = {
  81         .name           = "hpet",
  82         .rating         = 250,
  83         .read           = read_hpet,
  84         .mask           = CLOCKSOURCE_MASK(64),
  85         .mult           = 0, /* to be calculated */
  86         .shift          = 10,
  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         lock_kernel();
 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                 unlock_kernel();
 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         unlock_kernel();
 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_common(struct hpet_dev *, int, unsigned long, int);
 432
 433 static int
 434 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 435            unsigned long arg)
 436 {
 437         struct hpet_dev *devp;
 438
 439         devp = file->private_data;
 440         return hpet_ioctl_common(devp, cmd, arg, 0);
 441 }
 442
 443 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 444 {
 445         struct hpet_timer __iomem *timer;
 446         struct hpet __iomem *hpet;
 447         struct hpets *hpetp;
 448         int irq;
 449         unsigned long g, v, t, m;
 450         unsigned long flags, isr;
 451
 452         timer = devp->hd_timer;
 453         hpet = devp->hd_hpet;
 454         hpetp = devp->hd_hpets;
 455
 456         if (!devp->hd_ireqfreq)
 457                 return -EIO;
 458
 459         spin_lock_irq(&hpet_lock);
 460
 461         if (devp->hd_flags & HPET_IE) {
 462                 spin_unlock_irq(&hpet_lock);
 463                 return -EBUSY;
 464         }
 465
 466         devp->hd_flags |= HPET_IE;
 467
 468         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 469                 devp->hd_flags |= HPET_SHARED_IRQ;
 470         spin_unlock_irq(&hpet_lock);
 471
 472         irq = devp->hd_hdwirq;
 473
 474         if (irq) {
 475                 unsigned long irq_flags;
 476
 477                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 478                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 479                                                 ? IRQF_SHARED : IRQF_DISABLED;
 480                 if (request_irq(irq, hpet_interrupt, irq_flags,
 481                                 devp->hd_name, (void *)devp)) {
 482                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 483                         irq = 0;
 484                 }
 485         }
 486
 487         if (irq == 0) {
 488                 spin_lock_irq(&hpet_lock);
 489                 devp->hd_flags ^= HPET_IE;
 490                 spin_unlock_irq(&hpet_lock);
 491                 return -EIO;
 492         }
 493
 494         devp->hd_irq = irq;
 495         t = devp->hd_ireqfreq;
 496         v = readq(&timer->hpet_config);
 497
 498         /* 64-bit comparators are not yet supported through the ioctls,
 499          * so force this into 32-bit mode if it supports both modes
 500          */
 501         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 502
 503         if (devp->hd_flags & HPET_PERIODIC) {
 504                 g |= Tn_TYPE_CNF_MASK;
 505                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 506                 writeq(v, &timer->hpet_config);
 507                 local_irq_save(flags);
 508
 509                 /*
 510                  * NOTE: First we modify the hidden accumulator
 511                  * register supported by periodic-capable comparators.
 512                  * We never want to modify the (single) counter; that
 513                  * would affect all the comparators. The value written
 514                  * is the counter value when the first interrupt is due.
 515                  */
 516                 m = read_counter(&hpet->hpet_mc);
 517                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 518                 /*
 519                  * Then we modify the comparator, indicating the period
 520                  * for subsequent interrupt.
 521                  */
 522                 write_counter(t, &timer->hpet_compare);
 523         } else {
 524                 local_irq_save(flags);
 525                 m = read_counter(&hpet->hpet_mc);
 526                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 527         }
 528
 529         if (devp->hd_flags & HPET_SHARED_IRQ) {
 530                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 531                 writel(isr, &hpet->hpet_isr);
 532         }
 533         writeq(g, &timer->hpet_config);
 534         local_irq_restore(flags);
 535
 536         return 0;
 537 }
 538
 539 /* converts Hz to number of timer ticks */
 540 static inline unsigned long hpet_time_div(struct hpets *hpets,
 541                                           unsigned long dis)
 542 {
 543         unsigned long long m;
 544
 545         m = hpets->hp_tick_freq + (dis >> 1);
 546         do_div(m, dis);
 547         return (unsigned long)m;
 548 }
 549
 550 static int
 551 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
 552 {
 553         struct hpet_timer __iomem *timer;
 554         struct hpet __iomem *hpet;
 555         struct hpets *hpetp;
 556         int err;
 557         unsigned long v;
 558
 559         switch (cmd) {
 560         case HPET_IE_OFF:
 561         case HPET_INFO:
 562         case HPET_EPI:
 563         case HPET_DPI:
 564         case HPET_IRQFREQ:
 565                 timer = devp->hd_timer;
 566                 hpet = devp->hd_hpet;
 567                 hpetp = devp->hd_hpets;
 568                 break;
 569         case HPET_IE_ON:
 570                 return hpet_ioctl_ieon(devp);
 571         default:
 572                 return -EINVAL;
 573         }
 574
 575         err = 0;
 576
 577         switch (cmd) {
 578         case HPET_IE_OFF:
 579                 if ((devp->hd_flags & HPET_IE) == 0)
 580                         break;
 581                 v = readq(&timer->hpet_config);
 582                 v &= ~Tn_INT_ENB_CNF_MASK;
 583                 writeq(v, &timer->hpet_config);
 584                 if (devp->hd_irq) {
 585                         free_irq(devp->hd_irq, devp);
 586                         devp->hd_irq = 0;
 587                 }
 588                 devp->hd_flags ^= HPET_IE;
 589                 break;
 590         case HPET_INFO:
 591                 {
 592                         struct hpet_info info;
 593
 594                         if (devp->hd_ireqfreq)
 595                                 info.hi_ireqfreq =
 596                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 597                         else
 598                                 info.hi_ireqfreq = 0;
 599                         info.hi_flags =
 600                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 601                         info.hi_hpet = hpetp->hp_which;
 602                         info.hi_timer = devp - hpetp->hp_dev;
 603                         if (kernel)
 604                                 memcpy((void *)arg, &info, sizeof(info));
 605                         else
 606                                 if (copy_to_user((void __user *)arg, &info,
 607                                                  sizeof(info)))
 608                                         err = -EFAULT;
 609                         break;
 610                 }
 611         case HPET_EPI:
 612                 v = readq(&timer->hpet_config);
 613                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 614                         err = -ENXIO;
 615                         break;
 616                 }
 617                 devp->hd_flags |= HPET_PERIODIC;
 618                 break;
 619         case HPET_DPI:
 620                 v = readq(&timer->hpet_config);
 621                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 622                         err = -ENXIO;
 623                         break;
 624                 }
 625                 if (devp->hd_flags & HPET_PERIODIC &&
 626                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 627                         v = readq(&timer->hpet_config);
 628                         v ^= Tn_TYPE_CNF_MASK;
 629                         writeq(v, &timer->hpet_config);
 630                 }
 631                 devp->hd_flags &= ~HPET_PERIODIC;
 632                 break;
 633         case HPET_IRQFREQ:
 634                 if (!kernel && (arg > hpet_max_freq) &&
 635                     !capable(CAP_SYS_RESOURCE)) {
 636                         err = -EACCES;
 637                         break;
 638                 }
 639
 640                 if (!arg) {
 641                         err = -EINVAL;
 642                         break;
 643                 }
 644
 645                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 646         }
 647
 648         return err;
 649 }
 650
 651 static const struct file_operations hpet_fops = {
 652         .owner = THIS_MODULE,
 653         .llseek = no_llseek,
 654         .read = hpet_read,
 655         .poll = hpet_poll,
 656         .ioctl = hpet_ioctl,
 657         .open = hpet_open,
 658         .release = hpet_release,
 659         .fasync = hpet_fasync,
 660         .mmap = hpet_mmap,
 661 };
 662
 663 static int hpet_is_known(struct hpet_data *hdp)
 664 {
 665         struct hpets *hpetp;
 666
 667         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 668                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 669                         return 1;
 670
 671         return 0;
 672 }
 673
 674 static ctl_table hpet_table[] = {
 675         {
 676          .procname = "max-user-freq",
 677          .data = &hpet_max_freq,
 678          .maxlen = sizeof(int),
 679          .mode = 0644,
 680          .proc_handler = proc_dointvec,
 681          },
 682         {}
 683 };
 684
 685 static ctl_table hpet_root[] = {
 686         {
 687          .procname = "hpet",
 688          .maxlen = 0,
 689          .mode = 0555,
 690          .child = hpet_table,
 691          },
 692         {}
 693 };
 694
 695 static ctl_table dev_root[] = {
 696         {
 697          .procname = "dev",
 698          .maxlen = 0,
 699          .mode = 0555,
 700          .child = hpet_root,
 701          },
 702         {}
 703 };
 704
 705 static struct ctl_table_header *sysctl_header;
 706
 707 /*
 708  * Adjustment for when arming the timer with
 709  * initial conditions.  That is, main counter
 710  * ticks expired before interrupts are enabled.
 711  */
 712 #define TICK_CALIBRATE  (1000UL)
 713
 714 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 715 {
 716         struct hpet_timer __iomem *timer = NULL;
 717         unsigned long t, m, count, i, flags, start;
 718         struct hpet_dev *devp;
 719         int j;
 720         struct hpet __iomem *hpet;
 721
 722         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 723                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 724                         timer = devp->hd_timer;
 725                         break;
 726                 }
 727
 728         if (!timer)
 729                 return 0;
 730
 731         hpet = hpetp->hp_hpet;
 732         t = read_counter(&timer->hpet_compare);
 733
 734         i = 0;
 735         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 736
 737         local_irq_save(flags);
 738
 739         start = read_counter(&hpet->hpet_mc);
 740
 741         do {
 742                 m = read_counter(&hpet->hpet_mc);
 743                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 744         } while (i++, (m - start) < count);
 745
 746         local_irq_restore(flags);
 747
 748         return (m - start) / i;
 749 }
 750
 751 static unsigned long hpet_calibrate(struct hpets *hpetp)
 752 {
 753         unsigned long ret = -1;
 754         unsigned long tmp;
 755
 756         /*
 757          * Try to calibrate until return value becomes stable small value.
 758          * If SMI interruption occurs in calibration loop, the return value
 759          * will be big. This avoids its impact.
 760          */
 761         for ( ; ; ) {
 762                 tmp = __hpet_calibrate(hpetp);
 763                 if (ret <= tmp)
 764                         break;
 765                 ret = tmp;
 766         }
 767
 768         return ret;
 769 }
 770
 771 int hpet_alloc(struct hpet_data *hdp)
 772 {
 773         u64 cap, mcfg;
 774         struct hpet_dev *devp;
 775         u32 i, ntimer;
 776         struct hpets *hpetp;
 777         size_t siz;
 778         struct hpet __iomem *hpet;
 779         static struct hpets *last = NULL;
 780         unsigned long period;
 781         unsigned long long temp;
 782         u32 remainder;
 783
 784         /*
 785          * hpet_alloc can be called by platform dependent code.
 786          * If platform dependent code has allocated the hpet that
 787          * ACPI has also reported, then we catch it here.
 788          */
 789         if (hpet_is_known(hdp)) {
 790                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 791                         __func__);
 792                 return 0;
 793         }
 794
 795         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 796                                       sizeof(struct hpet_dev));
 797
 798         hpetp = kzalloc(siz, GFP_KERNEL);
 799
 800         if (!hpetp)
 801                 return -ENOMEM;
 802
 803         hpetp->hp_which = hpet_nhpet++;
 804         hpetp->hp_hpet = hdp->hd_address;
 805         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 806
 807         hpetp->hp_ntimer = hdp->hd_nirqs;
 808
 809         for (i = 0; i < hdp->hd_nirqs; i++)
 810                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 811
 812         hpet = hpetp->hp_hpet;
 813
 814         cap = readq(&hpet->hpet_cap);
 815
 816         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 817
 818         if (hpetp->hp_ntimer != ntimer) {
 819                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 820                        " with number of timers\n");
 821                 kfree(hpetp);
 822                 return -ENODEV;
 823         }
 824
 825         if (last)
 826                 last->hp_next = hpetp;
 827         else
 828                 hpets = hpetp;
 829
 830         last = hpetp;
 831
 832         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 833                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 834         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 835         temp += period >> 1; /* round */
 836         do_div(temp, period);
 837         hpetp->hp_tick_freq = temp; /* ticks per second */
 838
 839         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 840                 hpetp->hp_which, hdp->hd_phys_address,
 841                 hpetp->hp_ntimer > 1 ? "s" : "");
 842         for (i = 0; i < hpetp->hp_ntimer; i++)
 843                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 844         printk("\n");
 845
 846         temp = hpetp->hp_tick_freq;
 847         remainder = do_div(temp, 1000000);
 848         printk(KERN_INFO
 849                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 850                 hpetp->hp_which, hpetp->hp_ntimer,
 851                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 852                 (unsigned) temp, remainder);
 853
 854         mcfg = readq(&hpet->hpet_config);
 855         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 856                 write_counter(0L, &hpet->hpet_mc);
 857                 mcfg |= HPET_ENABLE_CNF_MASK;
 858                 writeq(mcfg, &hpet->hpet_config);
 859         }
 860
 861         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 862                 struct hpet_timer __iomem *timer;
 863
 864                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 865
 866                 devp->hd_hpets = hpetp;
 867                 devp->hd_hpet = hpet;
 868                 devp->hd_timer = timer;
 869
 870                 /*
 871                  * If the timer was reserved by platform code,
 872                  * then make timer unavailable for opens.
 873                  */
 874                 if (hdp->hd_state & (1 << i)) {
 875                         devp->hd_flags = HPET_OPEN;
 876                         continue;
 877                 }
 878
 879                 init_waitqueue_head(&devp->hd_waitqueue);
 880         }
 881
 882         hpetp->hp_delta = hpet_calibrate(hpetp);
 883
 884 /* This clocksource driver currently only works on ia64 */
 885 #ifdef CONFIG_IA64
 886         if (!hpet_clocksource) {
 887                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 888                 CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
 889                 clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
 890                                                 clocksource_hpet.shift);
 891                 clocksource_register(&clocksource_hpet);
 892                 hpetp->hp_clocksource = &clocksource_hpet;
 893                 hpet_clocksource = &clocksource_hpet;
 894         }
 895 #endif
 896
 897         return 0;
 898 }
 899
 900 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 901 {
 902         struct hpet_data *hdp;
 903         acpi_status status;
 904         struct acpi_resource_address64 addr;
 905
 906         hdp = data;
 907
 908         status = acpi_resource_to_address64(res, &addr);
 909
 910         if (ACPI_SUCCESS(status)) {
 911                 hdp->hd_phys_address = addr.minimum;
 912                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 913
 914                 if (hpet_is_known(hdp)) {
 915                         iounmap(hdp->hd_address);
 916                         return AE_ALREADY_EXISTS;
 917                 }
 918         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 919                 struct acpi_resource_fixed_memory32 *fixmem32;
 920
 921                 fixmem32 = &res->data.fixed_memory32;
 922                 if (!fixmem32)
 923                         return AE_NO_MEMORY;
 924
 925                 hdp->hd_phys_address = fixmem32->address;
 926                 hdp->hd_address = ioremap(fixmem32->address,
 927                                                 HPET_RANGE_SIZE);
 928
 929                 if (hpet_is_known(hdp)) {
 930                         iounmap(hdp->hd_address);
 931                         return AE_ALREADY_EXISTS;
 932                 }
 933         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 934                 struct acpi_resource_extended_irq *irqp;
 935                 int i, irq;
 936
 937                 irqp = &res->data.extended_irq;
 938
 939                 for (i = 0; i < irqp->interrupt_count; i++) {
 940                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
 941                                       irqp->triggering, irqp->polarity);
 942                         if (irq < 0)
 943                                 return AE_ERROR;
 944
 945                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 946                         hdp->hd_nirqs++;
 947                 }
 948         }
 949
 950         return AE_OK;
 951 }
 952
 953 static int hpet_acpi_add(struct acpi_device *device)
 954 {
 955         acpi_status result;
 956         struct hpet_data data;
 957
 958         memset(&data, 0, sizeof(data));
 959
 960         result =
 961             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 962                                 hpet_resources, &data);
 963
 964         if (ACPI_FAILURE(result))
 965                 return -ENODEV;
 966
 967         if (!data.hd_address || !data.hd_nirqs) {
 968                 printk("%s: no address or irqs in _CRS\n", __func__);
 969                 return -ENODEV;
 970         }
 971
 972         return hpet_alloc(&data);
 973 }
 974
 975 static int hpet_acpi_remove(struct acpi_device *device, int type)
 976 {
 977         /* XXX need to unregister clocksource, dealloc mem, etc */
 978         return -EINVAL;
 979 }
 980
 981 static const struct acpi_device_id hpet_device_ids[] = {
 982         {"PNP0103", 0},
 983         {"", 0},
 984 };
 985 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
 986
 987 static struct acpi_driver hpet_acpi_driver = {
 988         .name = "hpet",
 989         .ids = hpet_device_ids,
 990         .ops = {
 991                 .add = hpet_acpi_add,
 992                 .remove = hpet_acpi_remove,
 993                 },
 994 };
 995
 996 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
 997
 998 static int __init hpet_init(void)
 999 {
1000         int result;
1001
1002         result = misc_register(&hpet_misc);
1003         if (result < 0)
1004                 return -ENODEV;
1005
1006         sysctl_header = register_sysctl_table(dev_root);
1007
1008         result = acpi_bus_register_driver(&hpet_acpi_driver);
1009         if (result < 0) {
1010                 if (sysctl_header)
1011                         unregister_sysctl_table(sysctl_header);
1012                 misc_deregister(&hpet_misc);
1013                 return result;
1014         }
1015
1016         return 0;
1017 }
1018
1019 static void __exit hpet_exit(void)
1020 {
1021         acpi_bus_unregister_driver(&hpet_acpi_driver);
1022
1023         if (sysctl_header)
1024                 unregister_sysctl_table(sysctl_header);
1025         misc_deregister(&hpet_misc);
1026
1027         return;
1028 }
1029
1030 module_init(hpet_init);
1031 module_exit(hpet_exit);
1032 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1033 MODULE_LICENSE("GPL");