drivers/char/hpet.c

   1 /*
   2  * Intel & MS High Precision Event Timer Implementation.
   3  *
   4  * Copyright (C) 2003 Intel Corporation
   5  *      Venki Pallipadi
   6  * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
   7  *      Bob Picco <robert.picco@hp.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/interrupt.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/types.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/major.h>
  20 #include <linux/ioport.h>
  21 #include <linux/fcntl.h>
  22 #include <linux/init.h>
  23 #include <linux/poll.h>
  24 #include <linux/mm.h>
  25 #include <linux/proc_fs.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/wait.h>
  29 #include <linux/bcd.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/bitops.h>
  32 #include <linux/compat.h>
  33 #include <linux/clocksource.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/slab.h>
  36 #include <linux/io.h>
  37
  38 #include <asm/current.h>
  39 #include <asm/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 DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
  70 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  71
  72 /* This clocksource driver currently only works on ia64 */
  73 #ifdef CONFIG_IA64
  74 static void __iomem *hpet_mctr;
  75
  76 static cycle_t read_hpet(struct clocksource *cs)
  77 {
  78         return (cycle_t)read_counter((void __iomem *)hpet_mctr);
  79 }
  80
  81 static 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 };
  88 static struct clocksource *hpet_clocksource;
  89 #endif
  90
  91 /* A lock for concurrent access by app and isr hpet activity. */
  92 static DEFINE_SPINLOCK(hpet_lock);
  93
  94 #define HPET_DEV_NAME   (7)
  95
  96 struct 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
 110 struct 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
 122 static 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
 131 static 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
 138 static 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
 145 static 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
 204 static 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
 263 static 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
 301 static ssize_t
 302 hpet_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);
 341 out:
 342         __set_current_state(TASK_RUNNING);
 343         remove_wait_queue(&devp->hd_waitqueue, &wait);
 344
 345         return retval;
 346 }
 347
 348 static 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
 370 static 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
 389 static 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
 401 static 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
 439 static 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 ? IRQF_SHARED : 0;
 490                 if (request_irq(irq, hpet_interrupt, irq_flags,
 491                                 devp->hd_name, (void *)devp)) {
 492                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 493                         irq = 0;
 494                 }
 495         }
 496
 497         if (irq == 0) {
 498                 spin_lock_irq(&hpet_lock);
 499                 devp->hd_flags ^= HPET_IE;
 500                 spin_unlock_irq(&hpet_lock);
 501                 return -EIO;
 502         }
 503
 504         devp->hd_irq = irq;
 505         t = devp->hd_ireqfreq;
 506         v = readq(&timer->hpet_config);
 507
 508         /* 64-bit comparators are not yet supported through the ioctls,
 509          * so force this into 32-bit mode if it supports both modes
 510          */
 511         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 512
 513         if (devp->hd_flags & HPET_PERIODIC) {
 514                 g |= Tn_TYPE_CNF_MASK;
 515                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 516                 writeq(v, &timer->hpet_config);
 517                 local_irq_save(flags);
 518
 519                 /*
 520                  * NOTE: First we modify the hidden accumulator
 521                  * register supported by periodic-capable comparators.
 522                  * We never want to modify the (single) counter; that
 523                  * would affect all the comparators. The value written
 524                  * is the counter value when the first interrupt is due.
 525                  */
 526                 m = read_counter(&hpet->hpet_mc);
 527                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 528                 /*
 529                  * Then we modify the comparator, indicating the period
 530                  * for subsequent interrupt.
 531                  */
 532                 write_counter(t, &timer->hpet_compare);
 533         } else {
 534                 local_irq_save(flags);
 535                 m = read_counter(&hpet->hpet_mc);
 536                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 537         }
 538
 539         if (devp->hd_flags & HPET_SHARED_IRQ) {
 540                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 541                 writel(isr, &hpet->hpet_isr);
 542         }
 543         writeq(g, &timer->hpet_config);
 544         local_irq_restore(flags);
 545
 546         return 0;
 547 }
 548
 549 /* converts Hz to number of timer ticks */
 550 static inline unsigned long hpet_time_div(struct hpets *hpets,
 551                                           unsigned long dis)
 552 {
 553         unsigned long long m;
 554
 555         m = hpets->hp_tick_freq + (dis >> 1);
 556         do_div(m, dis);
 557         return (unsigned long)m;
 558 }
 559
 560 static int
 561 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg,
 562                   struct hpet_info *info)
 563 {
 564         struct hpet_timer __iomem *timer;
 565         struct hpet __iomem *hpet;
 566         struct hpets *hpetp;
 567         int err;
 568         unsigned long v;
 569
 570         switch (cmd) {
 571         case HPET_IE_OFF:
 572         case HPET_INFO:
 573         case HPET_EPI:
 574         case HPET_DPI:
 575         case HPET_IRQFREQ:
 576                 timer = devp->hd_timer;
 577                 hpet = devp->hd_hpet;
 578                 hpetp = devp->hd_hpets;
 579                 break;
 580         case HPET_IE_ON:
 581                 return hpet_ioctl_ieon(devp);
 582         default:
 583                 return -EINVAL;
 584         }
 585
 586         err = 0;
 587
 588         switch (cmd) {
 589         case HPET_IE_OFF:
 590                 if ((devp->hd_flags & HPET_IE) == 0)
 591                         break;
 592                 v = readq(&timer->hpet_config);
 593                 v &= ~Tn_INT_ENB_CNF_MASK;
 594                 writeq(v, &timer->hpet_config);
 595                 if (devp->hd_irq) {
 596                         free_irq(devp->hd_irq, devp);
 597                         devp->hd_irq = 0;
 598                 }
 599                 devp->hd_flags ^= HPET_IE;
 600                 break;
 601         case HPET_INFO:
 602                 {
 603                         memset(info, 0, sizeof(*info));
 604                         if (devp->hd_ireqfreq)
 605                                 info->hi_ireqfreq =
 606                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 607                         info->hi_flags =
 608                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 609                         info->hi_hpet = hpetp->hp_which;
 610                         info->hi_timer = devp - hpetp->hp_dev;
 611                         break;
 612                 }
 613         case HPET_EPI:
 614                 v = readq(&timer->hpet_config);
 615                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 616                         err = -ENXIO;
 617                         break;
 618                 }
 619                 devp->hd_flags |= HPET_PERIODIC;
 620                 break;
 621         case HPET_DPI:
 622                 v = readq(&timer->hpet_config);
 623                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 624                         err = -ENXIO;
 625                         break;
 626                 }
 627                 if (devp->hd_flags & HPET_PERIODIC &&
 628                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 629                         v = readq(&timer->hpet_config);
 630                         v ^= Tn_TYPE_CNF_MASK;
 631                         writeq(v, &timer->hpet_config);
 632                 }
 633                 devp->hd_flags &= ~HPET_PERIODIC;
 634                 break;
 635         case HPET_IRQFREQ:
 636                 if ((arg > hpet_max_freq) &&
 637                     !capable(CAP_SYS_RESOURCE)) {
 638                         err = -EACCES;
 639                         break;
 640                 }
 641
 642                 if (!arg) {
 643                         err = -EINVAL;
 644                         break;
 645                 }
 646
 647                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 648         }
 649
 650         return err;
 651 }
 652
 653 static long
 654 hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 655 {
 656         struct hpet_info info;
 657         int err;
 658
 659         mutex_lock(&hpet_mutex);
 660         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 661         mutex_unlock(&hpet_mutex);
 662
 663         if ((cmd == HPET_INFO) && !err &&
 664             (copy_to_user((void __user *)arg, &info, sizeof(info))))
 665                 err = -EFAULT;
 666
 667         return err;
 668 }
 669
 670 #ifdef CONFIG_COMPAT
 671 struct compat_hpet_info {
 672         compat_ulong_t hi_ireqfreq;     /* Hz */
 673         compat_ulong_t hi_flags;        /* information */
 674         unsigned short hi_hpet;
 675         unsigned short hi_timer;
 676 };
 677
 678 static long
 679 hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 680 {
 681         struct hpet_info info;
 682         int err;
 683
 684         mutex_lock(&hpet_mutex);
 685         err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
 686         mutex_unlock(&hpet_mutex);
 687
 688         if ((cmd == HPET_INFO) && !err) {
 689                 struct compat_hpet_info __user *u = compat_ptr(arg);
 690                 if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
 691                     put_user(info.hi_flags, &u->hi_flags) ||
 692                     put_user(info.hi_hpet, &u->hi_hpet) ||
 693                     put_user(info.hi_timer, &u->hi_timer))
 694                         err = -EFAULT;
 695         }
 696
 697         return err;
 698 }
 699 #endif
 700
 701 static const struct file_operations hpet_fops = {
 702         .owner = THIS_MODULE,
 703         .llseek = no_llseek,
 704         .read = hpet_read,
 705         .poll = hpet_poll,
 706         .unlocked_ioctl = hpet_ioctl,
 707 #ifdef CONFIG_COMPAT
 708         .compat_ioctl = hpet_compat_ioctl,
 709 #endif
 710         .open = hpet_open,
 711         .release = hpet_release,
 712         .fasync = hpet_fasync,
 713         .mmap = hpet_mmap,
 714 };
 715
 716 static int hpet_is_known(struct hpet_data *hdp)
 717 {
 718         struct hpets *hpetp;
 719
 720         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 721                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 722                         return 1;
 723
 724         return 0;
 725 }
 726
 727 static struct ctl_table hpet_table[] = {
 728         {
 729          .procname = "max-user-freq",
 730          .data = &hpet_max_freq,
 731          .maxlen = sizeof(int),
 732          .mode = 0644,
 733          .proc_handler = proc_dointvec,
 734          },
 735         {}
 736 };
 737
 738 static struct ctl_table hpet_root[] = {
 739         {
 740          .procname = "hpet",
 741          .maxlen = 0,
 742          .mode = 0555,
 743          .child = hpet_table,
 744          },
 745         {}
 746 };
 747
 748 static struct ctl_table dev_root[] = {
 749         {
 750          .procname = "dev",
 751          .maxlen = 0,
 752          .mode = 0555,
 753          .child = hpet_root,
 754          },
 755         {}
 756 };
 757
 758 static struct ctl_table_header *sysctl_header;
 759
 760 /*
 761  * Adjustment for when arming the timer with
 762  * initial conditions.  That is, main counter
 763  * ticks expired before interrupts are enabled.
 764  */
 765 #define TICK_CALIBRATE  (1000UL)
 766
 767 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 768 {
 769         struct hpet_timer __iomem *timer = NULL;
 770         unsigned long t, m, count, i, flags, start;
 771         struct hpet_dev *devp;
 772         int j;
 773         struct hpet __iomem *hpet;
 774
 775         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 776                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 777                         timer = devp->hd_timer;
 778                         break;
 779                 }
 780
 781         if (!timer)
 782                 return 0;
 783
 784         hpet = hpetp->hp_hpet;
 785         t = read_counter(&timer->hpet_compare);
 786
 787         i = 0;
 788         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 789
 790         local_irq_save(flags);
 791
 792         start = read_counter(&hpet->hpet_mc);
 793
 794         do {
 795                 m = read_counter(&hpet->hpet_mc);
 796                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 797         } while (i++, (m - start) < count);
 798
 799         local_irq_restore(flags);
 800
 801         return (m - start) / i;
 802 }
 803
 804 static unsigned long hpet_calibrate(struct hpets *hpetp)
 805 {
 806         unsigned long ret = ~0UL;
 807         unsigned long tmp;
 808
 809         /*
 810          * Try to calibrate until return value becomes stable small value.
 811          * If SMI interruption occurs in calibration loop, the return value
 812          * will be big. This avoids its impact.
 813          */
 814         for ( ; ; ) {
 815                 tmp = __hpet_calibrate(hpetp);
 816                 if (ret <= tmp)
 817                         break;
 818                 ret = tmp;
 819         }
 820
 821         return ret;
 822 }
 823
 824 int hpet_alloc(struct hpet_data *hdp)
 825 {
 826         u64 cap, mcfg;
 827         struct hpet_dev *devp;
 828         u32 i, ntimer;
 829         struct hpets *hpetp;
 830         size_t siz;
 831         struct hpet __iomem *hpet;
 832         static struct hpets *last;
 833         unsigned long period;
 834         unsigned long long temp;
 835         u32 remainder;
 836
 837         /*
 838          * hpet_alloc can be called by platform dependent code.
 839          * If platform dependent code has allocated the hpet that
 840          * ACPI has also reported, then we catch it here.
 841          */
 842         if (hpet_is_known(hdp)) {
 843                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 844                         __func__);
 845                 return 0;
 846         }
 847
 848         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 849                                       sizeof(struct hpet_dev));
 850
 851         hpetp = kzalloc(siz, GFP_KERNEL);
 852
 853         if (!hpetp)
 854                 return -ENOMEM;
 855
 856         hpetp->hp_which = hpet_nhpet++;
 857         hpetp->hp_hpet = hdp->hd_address;
 858         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 859
 860         hpetp->hp_ntimer = hdp->hd_nirqs;
 861
 862         for (i = 0; i < hdp->hd_nirqs; i++)
 863                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 864
 865         hpet = hpetp->hp_hpet;
 866
 867         cap = readq(&hpet->hpet_cap);
 868
 869         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 870
 871         if (hpetp->hp_ntimer != ntimer) {
 872                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 873                        " with number of timers\n");
 874                 kfree(hpetp);
 875                 return -ENODEV;
 876         }
 877
 878         if (last)
 879                 last->hp_next = hpetp;
 880         else
 881                 hpets = hpetp;
 882
 883         last = hpetp;
 884
 885         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 886                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 887         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 888         temp += period >> 1; /* round */
 889         do_div(temp, period);
 890         hpetp->hp_tick_freq = temp; /* ticks per second */
 891
 892         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 893                 hpetp->hp_which, hdp->hd_phys_address,
 894                 hpetp->hp_ntimer > 1 ? "s" : "");
 895         for (i = 0; i < hpetp->hp_ntimer; i++)
 896                 printk(KERN_CONT "%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 897         printk(KERN_CONT "\n");
 898
 899         temp = hpetp->hp_tick_freq;
 900         remainder = do_div(temp, 1000000);
 901         printk(KERN_INFO
 902                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 903                 hpetp->hp_which, hpetp->hp_ntimer,
 904                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 905                 (unsigned) temp, remainder);
 906
 907         mcfg = readq(&hpet->hpet_config);
 908         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 909                 write_counter(0L, &hpet->hpet_mc);
 910                 mcfg |= HPET_ENABLE_CNF_MASK;
 911                 writeq(mcfg, &hpet->hpet_config);
 912         }
 913
 914         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 915                 struct hpet_timer __iomem *timer;
 916
 917                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 918
 919                 devp->hd_hpets = hpetp;
 920                 devp->hd_hpet = hpet;
 921                 devp->hd_timer = timer;
 922
 923                 /*
 924                  * If the timer was reserved by platform code,
 925                  * then make timer unavailable for opens.
 926                  */
 927                 if (hdp->hd_state & (1 << i)) {
 928                         devp->hd_flags = HPET_OPEN;
 929                         continue;
 930                 }
 931
 932                 init_waitqueue_head(&devp->hd_waitqueue);
 933         }
 934
 935         hpetp->hp_delta = hpet_calibrate(hpetp);
 936
 937 /* This clocksource driver currently only works on ia64 */
 938 #ifdef CONFIG_IA64
 939         if (!hpet_clocksource) {
 940                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 941                 clocksource_hpet.archdata.fsys_mmio = hpet_mctr;
 942                 clocksource_register_hz(&clocksource_hpet, hpetp->hp_tick_freq);
 943                 hpetp->hp_clocksource = &clocksource_hpet;
 944                 hpet_clocksource = &clocksource_hpet;
 945         }
 946 #endif
 947
 948         return 0;
 949 }
 950
 951 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 952 {
 953         struct hpet_data *hdp;
 954         acpi_status status;
 955         struct acpi_resource_address64 addr;
 956
 957         hdp = data;
 958
 959         status = acpi_resource_to_address64(res, &addr);
 960
 961         if (ACPI_SUCCESS(status)) {
 962                 hdp->hd_phys_address = addr.minimum;
 963                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 964
 965                 if (hpet_is_known(hdp)) {
 966                         iounmap(hdp->hd_address);
 967                         return AE_ALREADY_EXISTS;
 968                 }
 969         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 970                 struct acpi_resource_fixed_memory32 *fixmem32;
 971
 972                 fixmem32 = &res->data.fixed_memory32;
 973
 974                 hdp->hd_phys_address = fixmem32->address;
 975                 hdp->hd_address = ioremap(fixmem32->address,
 976                                                 HPET_RANGE_SIZE);
 977
 978                 if (hpet_is_known(hdp)) {
 979                         iounmap(hdp->hd_address);
 980                         return AE_ALREADY_EXISTS;
 981                 }
 982         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 983                 struct acpi_resource_extended_irq *irqp;
 984                 int i, irq;
 985
 986                 irqp = &res->data.extended_irq;
 987
 988                 for (i = 0; i < irqp->interrupt_count; i++) {
 989                         if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
 990                                 break;
 991
 992                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
 993                                       irqp->triggering, irqp->polarity);
 994                         if (irq < 0)
 995                                 return AE_ERROR;
 996
 997                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 998                         hdp->hd_nirqs++;
 999                 }
1000         }
1001
1002         return AE_OK;
1003 }
1004
1005 static int hpet_acpi_add(struct acpi_device *device)
1006 {
1007         acpi_status result;
1008         struct hpet_data data;
1009
1010         memset(&data, 0, sizeof(data));
1011
1012         result =
1013             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
1014                                 hpet_resources, &data);
1015
1016         if (ACPI_FAILURE(result))
1017                 return -ENODEV;
1018
1019         if (!data.hd_address || !data.hd_nirqs) {
1020                 if (data.hd_address)
1021                         iounmap(data.hd_address);
1022                 printk("%s: no address or irqs in _CRS\n", __func__);
1023                 return -ENODEV;
1024         }
1025
1026         return hpet_alloc(&data);
1027 }
1028
1029 static int hpet_acpi_remove(struct acpi_device *device)
1030 {
1031         /* XXX need to unregister clocksource, dealloc mem, etc */
1032         return -EINVAL;
1033 }
1034
1035 static const struct acpi_device_id hpet_device_ids[] = {
1036         {"PNP0103", 0},
1037         {"", 0},
1038 };
1039 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
1040
1041 static struct acpi_driver hpet_acpi_driver = {
1042         .name = "hpet",
1043         .ids = hpet_device_ids,
1044         .ops = {
1045                 .add = hpet_acpi_add,
1046                 .remove = hpet_acpi_remove,
1047                 },
1048 };
1049
1050 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1051
1052 static int __init hpet_init(void)
1053 {
1054         int result;
1055
1056         result = misc_register(&hpet_misc);
1057         if (result < 0)
1058                 return -ENODEV;
1059
1060         sysctl_header = register_sysctl_table(dev_root);
1061
1062         result = acpi_bus_register_driver(&hpet_acpi_driver);
1063         if (result < 0) {
1064                 if (sysctl_header)
1065                         unregister_sysctl_table(sysctl_header);
1066                 misc_deregister(&hpet_misc);
1067                 return result;
1068         }
1069
1070         return 0;
1071 }
1072
1073 static void __exit hpet_exit(void)
1074 {
1075         acpi_bus_unregister_driver(&hpet_acpi_driver);
1076
1077         if (sysctl_header)
1078                 unregister_sysctl_table(sysctl_header);
1079         misc_deregister(&hpet_misc);
1080
1081         return;
1082 }
1083
1084 module_init(hpet_init);
1085 module_exit(hpet_exit);
1086 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1087 MODULE_LICENSE("GPL");