linux/drivers/char/hpet.c
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   1/*
   2 * Intel & MS High Precision Event Timer Implementation.
   3 *
   4 * Copyright (C) 2003 Intel Corporation
   5 *      Venki Pallipadi
   6 * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
   7 *      Bob Picco <robert.picco@hp.com>
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License version 2 as
  11 * published by the Free Software Foundation.
  12 */
  13
  14#include <linux/interrupt.h>
  15#include <linux/module.h>
  16#include <linux/kernel.h>
  17#include <linux/types.h>
  18#include <linux/miscdevice.h>
  19#include <linux/major.h>
  20#include <linux/ioport.h>
  21#include <linux/fcntl.h>
  22#include <linux/init.h>
  23#include <linux/poll.h>
  24#include <linux/mm.h>
  25#include <linux/proc_fs.h>
  26#include <linux/spinlock.h>
  27#include <linux/sysctl.h>
  28#include <linux/wait.h>
  29#include <linux/bcd.h>
  30#include <linux/seq_file.h>
  31#include <linux/bitops.h>
  32#include <linux/compat.h>
  33#include <linux/clocksource.h>
  34#include <linux/uaccess.h>
  35#include <linux/slab.h>
  36#include <linux/io.h>
  37
  38#include <asm/current.h>
  39#include <asm/irq.h>
  40#include <asm/div64.h>
  41
  42#include <linux/acpi.h>
  43#include <acpi/acpi_bus.h>
  44#include <linux/hpet.h>
  45
  46/*
  47 * The High Precision Event Timer driver.
  48 * This driver is closely modelled after the rtc.c driver.
  49 * http://www.intel.com/hardwaredesign/hpetspec_1.pdf
  50 */
  51#define HPET_USER_FREQ  (64)
  52#define HPET_DRIFT      (500)
  53
  54#define HPET_RANGE_SIZE         1024    /* from HPET spec */
  55
  56
  57/* WARNING -- don't get confused.  These macros are never used
  58 * to write the (single) counter, and rarely to read it.
  59 * They're badly named; to fix, someday.
  60 */
  61#if BITS_PER_LONG == 64
  62#define write_counter(V, MC)    writeq(V, MC)
  63#define read_counter(MC)        readq(MC)
  64#else
  65#define write_counter(V, MC)    writel(V, MC)
  66#define read_counter(MC)        readl(MC)
  67#endif
  68
  69static DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
  70static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  71
  72/* This clocksource driver currently only works on ia64 */
  73#ifdef CONFIG_IA64
  74static void __iomem *hpet_mctr;
  75
  76static cycle_t read_hpet(struct clocksource *cs)
  77{
  78        return (cycle_t)read_counter((void __iomem *)hpet_mctr);
  79}
  80
  81static struct clocksource clocksource_hpet = {
  82        .name           = "hpet",
  83        .rating         = 250,
  84        .read           = read_hpet,
  85        .mask           = CLOCKSOURCE_MASK(64),
  86        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  87};
  88static struct clocksource *hpet_clocksource;
  89#endif
  90
  91/* A lock for concurrent access by app and isr hpet activity. */
  92static DEFINE_SPINLOCK(hpet_lock);
  93
  94#define HPET_DEV_NAME   (7)
  95
  96struct hpet_dev {
  97        struct hpets *hd_hpets;
  98        struct hpet __iomem *hd_hpet;
  99        struct hpet_timer __iomem *hd_timer;
 100        unsigned long hd_ireqfreq;
 101        unsigned long hd_irqdata;
 102        wait_queue_head_t hd_waitqueue;
 103        struct fasync_struct *hd_async_queue;
 104        unsigned int hd_flags;
 105        unsigned int hd_irq;
 106        unsigned int hd_hdwirq;
 107        char hd_name[HPET_DEV_NAME];
 108};
 109
 110struct hpets {
 111        struct hpets *hp_next;
 112        struct hpet __iomem *hp_hpet;
 113        unsigned long hp_hpet_phys;
 114        struct clocksource *hp_clocksource;
 115        unsigned long long hp_tick_freq;
 116        unsigned long hp_delta;
 117        unsigned int hp_ntimer;
 118        unsigned int hp_which;
 119        struct hpet_dev hp_dev[1];
 120};
 121
 122static struct hpets *hpets;
 123
 124#define HPET_OPEN               0x0001
 125#define HPET_IE                 0x0002  /* interrupt enabled */
 126#define HPET_PERIODIC           0x0004
 127#define HPET_SHARED_IRQ         0x0008
 128
 129
 130#ifndef readq
 131static inline unsigned long long readq(void __iomem *addr)
 132{
 133        return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 134}
 135#endif
 136
 137#ifndef writeq
 138static inline void writeq(unsigned long long v, void __iomem *addr)
 139{
 140        writel(v & 0xffffffff, addr);
 141        writel(v >> 32, addr + 4);
 142}
 143#endif
 144
 145static irqreturn_t hpet_interrupt(int irq, void *data)
 146{
 147        struct hpet_dev *devp;
 148        unsigned long isr;
 149
 150        devp = data;
 151        isr = 1 << (devp - devp->hd_hpets->hp_dev);
 152
 153        if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 154            !(isr & readl(&devp->hd_hpet->hpet_isr)))
 155                return IRQ_NONE;
 156
 157        spin_lock(&hpet_lock);
 158        devp->hd_irqdata++;
 159
 160        /*
 161         * For non-periodic timers, increment the accumulator.
 162         * This has the effect of treating non-periodic like periodic.
 163         */
 164        if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 165                unsigned long m, t, mc, base, k;
 166                struct hpet __iomem *hpet = devp->hd_hpet;
 167                struct hpets *hpetp = devp->hd_hpets;
 168
 169                t = devp->hd_ireqfreq;
 170                m = read_counter(&devp->hd_timer->hpet_compare);
 171                mc = read_counter(&hpet->hpet_mc);
 172                /* The time for the next interrupt would logically be t + m,
 173                 * however, if we are very unlucky and the interrupt is delayed
 174                 * for longer than t then we will completely miss the next
 175                 * interrupt if we set t + m and an application will hang.
 176                 * Therefore we need to make a more complex computation assuming
 177                 * that there exists a k for which the following is true:
 178                 * k * t + base < mc + delta
 179                 * (k + 1) * t + base > mc + delta
 180                 * where t is the interval in hpet ticks for the given freq,
 181                 * base is the theoretical start value 0 < base < t,
 182                 * mc is the main counter value at the time of the interrupt,
 183                 * delta is the time it takes to write the a value to the
 184                 * comparator.
 185                 * k may then be computed as (mc - base + delta) / t .
 186                 */
 187                base = mc % t;
 188                k = (mc - base + hpetp->hp_delta) / t;
 189                write_counter(t * (k + 1) + base,
 190                              &devp->hd_timer->hpet_compare);
 191        }
 192
 193        if (devp->hd_flags & HPET_SHARED_IRQ)
 194                writel(isr, &devp->hd_hpet->hpet_isr);
 195        spin_unlock(&hpet_lock);
 196
 197        wake_up_interruptible(&devp->hd_waitqueue);
 198
 199        kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 200
 201        return IRQ_HANDLED;
 202}
 203
 204static void hpet_timer_set_irq(struct hpet_dev *devp)
 205{
 206        unsigned long v;
 207        int irq, gsi;
 208        struct hpet_timer __iomem *timer;
 209
 210        spin_lock_irq(&hpet_lock);
 211        if (devp->hd_hdwirq) {
 212                spin_unlock_irq(&hpet_lock);
 213                return;
 214        }
 215
 216        timer = devp->hd_timer;
 217
 218        /* we prefer level triggered mode */
 219        v = readl(&timer->hpet_config);
 220        if (!(v & Tn_INT_TYPE_CNF_MASK)) {
 221                v |= Tn_INT_TYPE_CNF_MASK;
 222                writel(v, &timer->hpet_config);
 223        }
 224        spin_unlock_irq(&hpet_lock);
 225
 226        v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
 227                                 Tn_INT_ROUTE_CAP_SHIFT;
 228
 229        /*
 230         * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
 231         * legacy device. In IO APIC mode, we skip all the legacy IRQS.
 232         */
 233        if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 234                v &= ~0xf3df;
 235        else
 236                v &= ~0xffff;
 237
 238        for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
 239                if (irq >= nr_irqs) {
 240                        irq = HPET_MAX_IRQ;
 241                        break;
 242                }
 243
 244                gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
 245                                        ACPI_ACTIVE_LOW);
 246                if (gsi > 0)
 247                        break;
 248
 249                /* FIXME: Setup interrupt source table */
 250        }
 251
 252        if (irq < HPET_MAX_IRQ) {
 253                spin_lock_irq(&hpet_lock);
 254                v = readl(&timer->hpet_config);
 255                v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 256                writel(v, &timer->hpet_config);
 257                devp->hd_hdwirq = gsi;
 258                spin_unlock_irq(&hpet_lock);
 259        }
 260        return;
 261}
 262
 263static int hpet_open(struct inode *inode, struct file *file)
 264{
 265        struct hpet_dev *devp;
 266        struct hpets *hpetp;
 267        int i;
 268
 269        if (file->f_mode & FMODE_WRITE)
 270                return -EINVAL;
 271
 272        mutex_lock(&hpet_mutex);
 273        spin_lock_irq(&hpet_lock);
 274
 275        for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 276                for (i = 0; i < hpetp->hp_ntimer; i++)
 277                        if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
 278                                continue;
 279                        else {
 280                                devp = &hpetp->hp_dev[i];
 281                                break;
 282                        }
 283
 284        if (!devp) {
 285                spin_unlock_irq(&hpet_lock);
 286                mutex_unlock(&hpet_mutex);
 287                return -EBUSY;
 288        }
 289
 290        file->private_data = devp;
 291        devp->hd_irqdata = 0;
 292        devp->hd_flags |= HPET_OPEN;
 293        spin_unlock_irq(&hpet_lock);
 294        mutex_unlock(&hpet_mutex);
 295
 296        hpet_timer_set_irq(devp);
 297
 298        return 0;
 299}
 300
 301static ssize_t
 302hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 303{
 304        DECLARE_WAITQUEUE(wait, current);
 305        unsigned long data;
 306        ssize_t retval;
 307        struct hpet_dev *devp;
 308
 309        devp = file->private_data;
 310        if (!devp->hd_ireqfreq)
 311                return -EIO;
 312
 313        if (count < sizeof(unsigned long))
 314                return -EINVAL;
 315
 316        add_wait_queue(&devp->hd_waitqueue, &wait);
 317
 318        for ( ; ; ) {
 319                set_current_state(TASK_INTERRUPTIBLE);
 320
 321                spin_lock_irq(&hpet_lock);
 322                data = devp->hd_irqdata;
 323                devp->hd_irqdata = 0;
 324                spin_unlock_irq(&hpet_lock);
 325
 326                if (data)
 327                        break;
 328                else if (file->f_flags & O_NONBLOCK) {
 329                        retval = -EAGAIN;
 330                        goto out;
 331                } else if (signal_pending(current)) {
 332                        retval = -ERESTARTSYS;
 333                        goto out;
 334                }
 335                schedule();
 336        }
 337
 338        retval = put_user(data, (unsigned long __user *)buf);
 339        if (!retval)
 340                retval = sizeof(unsigned long);
 341out:
 342        __set_current_state(TASK_RUNNING);
 343        remove_wait_queue(&devp->hd_waitqueue, &wait);
 344
 345        return retval;
 346}
 347
 348static unsigned int hpet_poll(struct file *file, poll_table * wait)
 349{
 350        unsigned long v;
 351        struct hpet_dev *devp;
 352
 353        devp = file->private_data;
 354
 355        if (!devp->hd_ireqfreq)
 356                return 0;
 357
 358        poll_wait(file, &devp->hd_waitqueue, wait);
 359
 360        spin_lock_irq(&hpet_lock);
 361        v = devp->hd_irqdata;
 362        spin_unlock_irq(&hpet_lock);
 363
 364        if (v != 0)
 365                return POLLIN | POLLRDNORM;
 366
 367        return 0;
 368}
 369
 370static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 371{
 372#ifdef  CONFIG_HPET_MMAP
 373        struct hpet_dev *devp;
 374        unsigned long addr;
 375
 376        devp = file->private_data;
 377        addr = devp->hd_hpets->hp_hpet_phys;
 378
 379        if (addr & (PAGE_SIZE - 1))
 380                return -ENOSYS;
 381
 382        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 383        return vm_iomap_memory(vma, addr, PAGE_SIZE);
 384#else
 385        return -ENOSYS;
 386#endif
 387}
 388
 389static int hpet_fasync(int fd, struct file *file, int on)
 390{
 391        struct hpet_dev *devp;
 392
 393        devp = file->private_data;
 394
 395        if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 396                return 0;
 397        else
 398                return -EIO;
 399}
 400
 401static int hpet_release(struct inode *inode, struct file *file)
 402{
 403        struct hpet_dev *devp;
 404        struct hpet_timer __iomem *timer;
 405        int irq = 0;
 406
 407        devp = file->private_data;
 408        timer = devp->hd_timer;
 409
 410        spin_lock_irq(&hpet_lock);
 411
 412        writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 413               &timer->hpet_config);
 414
 415        irq = devp->hd_irq;
 416        devp->hd_irq = 0;
 417
 418        devp->hd_ireqfreq = 0;
 419
 420        if (devp->hd_flags & HPET_PERIODIC
 421            && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 422                unsigned long v;
 423
 424                v = readq(&timer->hpet_config);
 425                v ^= Tn_TYPE_CNF_MASK;
 426                writeq(v, &timer->hpet_config);
 427        }
 428
 429        devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 430        spin_unlock_irq(&hpet_lock);
 431
 432        if (irq)
 433                free_irq(irq, devp);
 434
 435        file->private_data = NULL;
 436        return 0;
 437}
 438
 439static int hpet_ioctl_ieon(struct hpet_dev *devp)
 440{
 441        struct hpet_timer __iomem *timer;
 442        struct hpet __iomem *hpet;
 443        struct hpets *hpetp;
 444        int irq;
 445        unsigned long g, v, t, m;
 446        unsigned long flags, isr;
 447
 448        timer = devp->hd_timer;
 449        hpet = devp->hd_hpet;
 450        hpetp = devp->hd_hpets;
 451
 452        if (!devp->hd_ireqfreq)
 453                return -EIO;
 454
 455        spin_lock_irq(&hpet_lock);
 456
 457        if (devp->hd_flags & HPET_IE) {
 458                spin_unlock_irq(&hpet_lock);
 459                return -EBUSY;
 460        }
 461
 462        devp->hd_flags |= HPET_IE;
 463
 464        if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 465                devp->hd_flags |= HPET_SHARED_IRQ;
 466        spin_unlock_irq(&hpet_lock);
 467
 468        irq = devp->hd_hdwirq;
 469
 470        if (irq) {
 471                unsigned long irq_flags;
 472
 473                if (devp->hd_flags & HPET_SHARED_IRQ) {
 474                        /*
 475                         * To prevent the interrupt handler from seeing an
 476                         * unwanted interrupt status bit, program the timer
 477                         * so that it will not fire in the near future ...
 478                         */
 479                        writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
 480                               &timer->hpet_config);
 481                        write_counter(read_counter(&hpet->hpet_mc),
 482                                      &timer->hpet_compare);
 483                        /* ... and clear any left-over status. */
 484                        isr = 1 << (devp - devp->hd_hpets->hp_dev);
 485                        writel(isr, &hpet->hpet_isr);
 486                }
 487
 488                sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 489                irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 490                                                ? IRQF_SHARED : IRQF_DISABLED;
 491                if (request_irq(irq, hpet_interrupt, irq_flags,
 492                                devp->hd_name, (void *)devp)) {
 493                        printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 494                        irq = 0;
 495                }
 496        }
 497
 498        if (irq == 0) {
 499                spin_lock_irq(&hpet_lock);
 500                devp->hd_flags ^= HPET_IE;
 501                spin_unlock_irq(&hpet_lock);
 502                return -EIO;
 503        }
 504
 505        devp->hd_irq = irq;
 506        t = devp->hd_ireqfreq;
 507        v = readq(&timer->hpet_config);
 508
 509        /* 64-bit comparators are not yet supported through the ioctls,
 510         * so force this into 32-bit mode if it supports both modes
 511         */
 512        g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 513
 514        if (devp->hd_flags & HPET_PERIODIC) {
 515                g |= Tn_TYPE_CNF_MASK;
 516                v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 517                writeq(v, &timer->hpet_config);
 518                local_irq_save(flags);
 519
 520                /*
 521                 * NOTE: First we modify the hidden accumulator
 522                 * register supported by periodic-capable comparators.
 523                 * We never want to modify the (single) counter; that
 524                 * would affect all the comparators. The value written
 525                 * is the counter value when the first interrupt is due.
 526                 */
 527                m = read_counter(&hpet->hpet_mc);
 528                write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 529                /*
 530                 * Then we modify the comparator, indicating the period
 531                 * for subsequent interrupt.
 532                 */
 533                write_counter(t, &timer->hpet_compare);
 534        } else {
 535                local_irq_save(flags);
 536                m = read_counter(&hpet->hpet_mc);
 537                write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 538        }
 539
 540        if (devp->hd_flags & HPET_SHARED_IRQ) {
 541                isr = 1 << (devp - devp->hd_hpets->hp_dev);
 542                writel(isr, &hpet->hpet_isr);
 543        }
 544        writeq(g, &timer->hpet_config);
 545        local_irq_restore(flags);
 546
 547        return 0;
 548}
 549
 550/* converts Hz to number of timer ticks */
 551static inline unsigned long hpet_time_div(struct hpets *hpets,
 552                                          unsigned long dis)
 553{
 554        unsigned long long m;
 555
 556        m = hpets->hp_tick_freq + (dis >> 1);
 557        do_div(m, dis);
 558        return (unsigned long)m;
 559}
 560
 561static int
 562hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg,
 563                  struct hpet_info *info)
 564{
 565        struct hpet_timer __iomem *timer;
 566        struct hpet __iomem *hpet;
 567        struct hpets *hpetp;
 568        int err;
 569        unsigned long v;
 570
 571        switch (cmd) {
 572        case HPET_IE_OFF:
 573        case HPET_INFO:
 574        case HPET_EPI:
 575        case HPET_DPI:
 576        case HPET_IRQFREQ:
 577                timer = devp->hd_timer;
 578                hpet = devp->hd_hpet;
 579                hpetp = devp->hd_hpets;
 580                break;
 581        case HPET_IE_ON:
 582                return hpet_ioctl_ieon(devp);
 583        default:
 584                return -EINVAL;
 585        }
 586
 587        err = 0;
 588
 589        switch (cmd) {
 590        case HPET_IE_OFF:
 591                if ((devp->hd_flags & HPET_IE) == 0)
 592                        break;
 593                v = readq(&timer->hpet_config);
 594                v &= ~Tn_INT_ENB_CNF_MASK;
 595                writeq(v, &timer->hpet_config);
 596                if (devp->hd_irq) {
 597                        free_irq(devp->hd_irq, devp);
 598                        devp->hd_irq = 0;
 599                }
 600                devp->hd_flags ^= HPET_IE;
 601                break;
 602        case HPET_INFO:
 603                {
 604                        memset(info, 0, sizeof(*info));
 605                        if (devp->hd_ireqfreq)
 606                                info->hi_ireqfreq =
 607                                        hpet_time_div(hpetp, devp->hd_ireqfreq);
 608                        info->hi_flags =
 609                            readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 610                        info->hi_hpet = hpetp->hp_which;
 611                        info->hi_timer = devp - hpetp->hp_dev;
 612                        break;
 613                }
 614        case HPET_EPI:
 615                v = readq(&timer->hpet_config);
 616                if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 617                        err = -ENXIO;
 618                        break;
 619                }
 620                devp->hd_flags |= HPET_PERIODIC;
 621                break;
 622        case HPET_DPI:
 623                v = readq(&timer->hpet_config);
 624                if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 625                        err = -ENXIO;
 626                        break;
 627                }
 628                if (devp->hd_flags & HPET_PERIODIC &&
 629                    readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 630                        v = readq(&timer->hpet_config);
 631                        v ^= Tn_TYPE_CNF_MASK;
 632                        writeq(v, &timer->hpet_config);
 633                }
 634                devp->hd_flags &= ~HPET_PERIODIC;
 635                break;
 636        case HPET_IRQFREQ:
 637                if ((arg > hpet_max_freq) &&
 638                    !capable(CAP_SYS_RESOURCE)) {
 639                        err = -EACCES;
 640                        break;
 641                }
 642
 643                if (!arg) {
 644                        err = -EINVAL;
 645                        break;
 646                }
 647
 648                devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 649        }
 650
 651        return err;
 652}
 653
 654static long
 655hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 656{
 657        struct hpet_info info;
 658        int err;
 659
 660        mutex_lock(&hpet_mutex);
 661        err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 662        mutex_unlock(&hpet_mutex);
 663
 664        if ((cmd == HPET_INFO) && !err &&
 665            (copy_to_user((void __user *)arg, &info, sizeof(info))))
 666                err = -EFAULT;
 667
 668        return err;
 669}
 670
 671#ifdef CONFIG_COMPAT
 672struct compat_hpet_info {
 673        compat_ulong_t hi_ireqfreq;     /* Hz */
 674        compat_ulong_t hi_flags;        /* information */
 675        unsigned short hi_hpet;
 676        unsigned short hi_timer;
 677};
 678
 679static long
 680hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 681{
 682        struct hpet_info info;
 683        int err;
 684
 685        mutex_lock(&hpet_mutex);
 686        err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 687        mutex_unlock(&hpet_mutex);
 688
 689        if ((cmd == HPET_INFO) && !err) {
 690                struct compat_hpet_info __user *u = compat_ptr(arg);
 691                if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
 692                    put_user(info.hi_flags, &u->hi_flags) ||
 693                    put_user(info.hi_hpet, &u->hi_hpet) ||
 694                    put_user(info.hi_timer, &u->hi_timer))
 695                        err = -EFAULT;
 696        }
 697
 698        return err;
 699}
 700#endif
 701
 702static const struct file_operations hpet_fops = {
 703        .owner = THIS_MODULE,
 704        .llseek = no_llseek,
 705        .read = hpet_read,
 706        .poll = hpet_poll,
 707        .unlocked_ioctl = hpet_ioctl,
 708#ifdef CONFIG_COMPAT
 709        .compat_ioctl = hpet_compat_ioctl,
 710#endif
 711        .open = hpet_open,
 712        .release = hpet_release,
 713        .fasync = hpet_fasync,
 714        .mmap = hpet_mmap,
 715};
 716
 717static int hpet_is_known(struct hpet_data *hdp)
 718{
 719        struct hpets *hpetp;
 720
 721        for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 722                if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 723                        return 1;
 724
 725        return 0;
 726}
 727
 728static ctl_table hpet_table[] = {
 729        {
 730         .procname = "max-user-freq",
 731         .data = &hpet_max_freq,
 732         .maxlen = sizeof(int),
 733         .mode = 0644,
 734         .proc_handler = proc_dointvec,
 735         },
 736        {}
 737};
 738
 739static ctl_table hpet_root[] = {
 740        {
 741         .procname = "hpet",
 742         .maxlen = 0,
 743         .mode = 0555,
 744         .child = hpet_table,
 745         },
 746        {}
 747};
 748
 749static ctl_table dev_root[] = {
 750        {
 751         .procname = "dev",
 752         .maxlen = 0,
 753         .mode = 0555,
 754         .child = hpet_root,
 755         },
 756        {}
 757};
 758
 759static struct ctl_table_header *sysctl_header;
 760
 761/*
 762 * Adjustment for when arming the timer with
 763 * initial conditions.  That is, main counter
 764 * ticks expired before interrupts are enabled.
 765 */
 766#define TICK_CALIBRATE  (1000UL)
 767
 768static unsigned long __hpet_calibrate(struct hpets *hpetp)
 769{
 770        struct hpet_timer __iomem *timer = NULL;
 771        unsigned long t, m, count, i, flags, start;
 772        struct hpet_dev *devp;
 773        int j;
 774        struct hpet __iomem *hpet;
 775
 776        for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 777                if ((devp->hd_flags & HPET_OPEN) == 0) {
 778                        timer = devp->hd_timer;
 779                        break;
 780                }
 781
 782        if (!timer)
 783                return 0;
 784
 785        hpet = hpetp->hp_hpet;
 786        t = read_counter(&timer->hpet_compare);
 787
 788        i = 0;
 789        count = hpet_time_div(hpetp, TICK_CALIBRATE);
 790
 791        local_irq_save(flags);
 792
 793        start = read_counter(&hpet->hpet_mc);
 794
 795        do {
 796                m = read_counter(&hpet->hpet_mc);
 797                write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 798        } while (i++, (m - start) < count);
 799
 800        local_irq_restore(flags);
 801
 802        return (m - start) / i;
 803}
 804
 805static unsigned long hpet_calibrate(struct hpets *hpetp)
 806{
 807        unsigned long ret = ~0UL;
 808        unsigned long tmp;
 809
 810        /*
 811         * Try to calibrate until return value becomes stable small value.
 812         * If SMI interruption occurs in calibration loop, the return value
 813         * will be big. This avoids its impact.
 814         */
 815        for ( ; ; ) {
 816                tmp = __hpet_calibrate(hpetp);
 817                if (ret <= tmp)
 818                        break;
 819                ret = tmp;
 820        }
 821
 822        return ret;
 823}
 824
 825int hpet_alloc(struct hpet_data *hdp)
 826{
 827        u64 cap, mcfg;
 828        struct hpet_dev *devp;
 829        u32 i, ntimer;
 830        struct hpets *hpetp;
 831        size_t siz;
 832        struct hpet __iomem *hpet;
 833        static struct hpets *last;
 834        unsigned long period;
 835        unsigned long long temp;
 836        u32 remainder;
 837
 838        /*
 839         * hpet_alloc can be called by platform dependent code.
 840         * If platform dependent code has allocated the hpet that
 841         * ACPI has also reported, then we catch it here.
 842         */
 843        if (hpet_is_known(hdp)) {
 844                printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 845                        __func__);
 846                return 0;
 847        }
 848
 849        siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 850                                      sizeof(struct hpet_dev));
 851
 852        hpetp = kzalloc(siz, GFP_KERNEL);
 853
 854        if (!hpetp)
 855                return -ENOMEM;
 856
 857        hpetp->hp_which = hpet_nhpet++;
 858        hpetp->hp_hpet = hdp->hd_address;
 859        hpetp->hp_hpet_phys = hdp->hd_phys_address;
 860
 861        hpetp->hp_ntimer = hdp->hd_nirqs;
 862
 863        for (i = 0; i < hdp->hd_nirqs; i++)
 864                hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 865
 866        hpet = hpetp->hp_hpet;
 867
 868        cap = readq(&hpet->hpet_cap);
 869
 870        ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 871
 872        if (hpetp->hp_ntimer != ntimer) {
 873                printk(KERN_WARNING "hpet: number irqs doesn't agree"
 874                       " with number of timers\n");
 875                kfree(hpetp);
 876                return -ENODEV;
 877        }
 878
 879        if (last)
 880                last->hp_next = hpetp;
 881        else
 882                hpets = hpetp;
 883
 884        last = hpetp;
 885
 886        period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 887                HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 888        temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 889        temp += period >> 1; /* round */
 890        do_div(temp, period);
 891        hpetp->hp_tick_freq = temp; /* ticks per second */
 892
 893        printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 894                hpetp->hp_which, hdp->hd_phys_address,
 895                hpetp->hp_ntimer > 1 ? "s" : "");
 896        for (i = 0; i < hpetp->hp_ntimer; i++)
 897                printk(KERN_CONT "%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 898        printk(KERN_CONT "\n");
 899
 900        temp = hpetp->hp_tick_freq;
 901        remainder = do_div(temp, 1000000);
 902        printk(KERN_INFO
 903                "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 904                hpetp->hp_which, hpetp->hp_ntimer,
 905                cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 906                (unsigned) temp, remainder);
 907
 908        mcfg = readq(&hpet->hpet_config);
 909        if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 910                write_counter(0L, &hpet->hpet_mc);
 911                mcfg |= HPET_ENABLE_CNF_MASK;
 912                writeq(mcfg, &hpet->hpet_config);
 913        }
 914
 915        for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 916                struct hpet_timer __iomem *timer;
 917
 918                timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 919
 920                devp->hd_hpets = hpetp;
 921                devp->hd_hpet = hpet;
 922                devp->hd_timer = timer;
 923
 924                /*
 925                 * If the timer was reserved by platform code,
 926                 * then make timer unavailable for opens.
 927                 */
 928                if (hdp->hd_state & (1 << i)) {
 929                        devp->hd_flags = HPET_OPEN;
 930                        continue;
 931                }
 932
 933                init_waitqueue_head(&devp->hd_waitqueue);
 934        }
 935
 936        hpetp->hp_delta = hpet_calibrate(hpetp);
 937
 938/* This clocksource driver currently only works on ia64 */
 939#ifdef CONFIG_IA64
 940        if (!hpet_clocksource) {
 941                hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 942                clocksource_hpet.archdata.fsys_mmio = hpet_mctr;
 943                clocksource_register_hz(&clocksource_hpet, hpetp->hp_tick_freq);
 944                hpetp->hp_clocksource = &clocksource_hpet;
 945                hpet_clocksource = &clocksource_hpet;
 946        }
 947#endif
 948
 949        return 0;
 950}
 951
 952static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 953{
 954        struct hpet_data *hdp;
 955        acpi_status status;
 956        struct acpi_resource_address64 addr;
 957
 958        hdp = data;
 959
 960        status = acpi_resource_to_address64(res, &addr);
 961
 962        if (ACPI_SUCCESS(status)) {
 963                hdp->hd_phys_address = addr.minimum;
 964                hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 965
 966                if (hpet_is_known(hdp)) {
 967                        iounmap(hdp->hd_address);
 968                        return AE_ALREADY_EXISTS;
 969                }
 970        } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 971                struct acpi_resource_fixed_memory32 *fixmem32;
 972
 973                fixmem32 = &res->data.fixed_memory32;
 974                if (!fixmem32)
 975                        return AE_NO_MEMORY;
 976
 977                hdp->hd_phys_address = fixmem32->address;
 978                hdp->hd_address = ioremap(fixmem32->address,
 979                                                HPET_RANGE_SIZE);
 980
 981                if (hpet_is_known(hdp)) {
 982                        iounmap(hdp->hd_address);
 983                        return AE_ALREADY_EXISTS;
 984                }
 985        } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 986                struct acpi_resource_extended_irq *irqp;
 987                int i, irq;
 988
 989                irqp = &res->data.extended_irq;
 990
 991                for (i = 0; i < irqp->interrupt_count; i++) {
 992                        if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
 993                                break;
 994
 995                        irq = acpi_register_gsi(NULL, irqp->interrupts[i],
 996                                      irqp->triggering, irqp->polarity);
 997                        if (irq < 0)
 998                                return AE_ERROR;
 999
1000                        hdp->hd_irq[hdp->hd_nirqs] = irq;
1001                        hdp->hd_nirqs++;
1002                }
1003        }
1004
1005        return AE_OK;
1006}
1007
1008static int hpet_acpi_add(struct acpi_device *device)
1009{
1010        acpi_status result;
1011        struct hpet_data data;
1012
1013        memset(&data, 0, sizeof(data));
1014
1015        result =
1016            acpi_walk_resources(device->handle, METHOD_NAME__CRS,
1017                                hpet_resources, &data);
1018
1019        if (ACPI_FAILURE(result))
1020                return -ENODEV;
1021
1022        if (!data.hd_address || !data.hd_nirqs) {
1023                if (data.hd_address)
1024                        iounmap(data.hd_address);
1025                printk("%s: no address or irqs in _CRS\n", __func__);
1026                return -ENODEV;
1027        }
1028
1029        return hpet_alloc(&data);
1030}
1031
1032static int hpet_acpi_remove(struct acpi_device *device, int type)
1033{
1034        /* XXX need to unregister clocksource, dealloc mem, etc */
1035        return -EINVAL;
1036}
1037
1038static const struct acpi_device_id hpet_device_ids[] = {
1039        {"PNP0103", 0},
1040        {"", 0},
1041};
1042MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
1043
1044static struct acpi_driver hpet_acpi_driver = {
1045        .name = "hpet",
1046        .ids = hpet_device_ids,
1047        .ops = {
1048                .add = hpet_acpi_add,
1049                .remove = hpet_acpi_remove,
1050                },
1051};
1052
1053static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1054
1055static int __init hpet_init(void)
1056{
1057        int result;
1058
1059        result = misc_register(&hpet_misc);
1060        if (result < 0)
1061                return -ENODEV;
1062
1063        sysctl_header = register_sysctl_table(dev_root);
1064
1065        result = acpi_bus_register_driver(&hpet_acpi_driver);
1066        if (result < 0) {
1067                if (sysctl_header)
1068                        unregister_sysctl_table(sysctl_header);
1069                misc_deregister(&hpet_misc);
1070                return result;
1071        }
1072
1073        return 0;
1074}
1075
1076static void __exit hpet_exit(void)
1077{
1078        acpi_bus_unregister_driver(&hpet_acpi_driver);
1079
1080        if (sysctl_header)
1081                unregister_sysctl_table(sysctl_header);
1082        misc_deregister(&hpet_misc);
1083
1084        return;
1085}
1086
1087module_init(hpet_init);
1088module_exit(hpet_exit);
1089MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1090MODULE_LICENSE("GPL");
1091
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