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