drivers/char/hpet.c

   1 /*
   2  * Intel & MS High Precision Event Timer Implementation.
   3  *
   4  * Copyright (C) 2003 Intel Corporation
   5  *      Venki Pallipadi
   6  * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
   7  *      Bob Picco <robert.picco@hp.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/interrupt.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/types.h>
  19 #include <linux/miscdevice.h>
  20 #include <linux/major.h>
  21 #include <linux/ioport.h>
  22 #include <linux/fcntl.h>
  23 #include <linux/init.h>
  24 #include <linux/poll.h>
  25 #include <linux/mm.h>
  26 #include <linux/proc_fs.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/sysctl.h>
  29 #include <linux/wait.h>
  30 #include <linux/bcd.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/bitops.h>
  33 #include <linux/clocksource.h>
  34 #include <linux/slab.h>
  35
  36 #include <asm/current.h>
  37 #include <asm/uaccess.h>
  38 #include <asm/system.h>
  39 #include <asm/io.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 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         .mult           = 0, /* to be calculated */
  87         .shift          = 10,
  88         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  89 };
  90 static struct clocksource *hpet_clocksource;
  91 #endif
  92
  93 /* A lock for concurrent access by app and isr hpet activity. */
  94 static DEFINE_SPINLOCK(hpet_lock);
  95
  96 #define HPET_DEV_NAME   (7)
  97
  98 struct hpet_dev {
  99         struct hpets *hd_hpets;
 100         struct hpet __iomem *hd_hpet;
 101         struct hpet_timer __iomem *hd_timer;
 102         unsigned long hd_ireqfreq;
 103         unsigned long hd_irqdata;
 104         wait_queue_head_t hd_waitqueue;
 105         struct fasync_struct *hd_async_queue;
 106         unsigned int hd_flags;
 107         unsigned int hd_irq;
 108         unsigned int hd_hdwirq;
 109         char hd_name[HPET_DEV_NAME];
 110 };
 111
 112 struct hpets {
 113         struct hpets *hp_next;
 114         struct hpet __iomem *hp_hpet;
 115         unsigned long hp_hpet_phys;
 116         struct clocksource *hp_clocksource;
 117         unsigned long long hp_tick_freq;
 118         unsigned long hp_delta;
 119         unsigned int hp_ntimer;
 120         unsigned int hp_which;
 121         struct hpet_dev hp_dev[1];
 122 };
 123
 124 static struct hpets *hpets;
 125
 126 #define HPET_OPEN               0x0001
 127 #define HPET_IE                 0x0002  /* interrupt enabled */
 128 #define HPET_PERIODIC           0x0004
 129 #define HPET_SHARED_IRQ         0x0008
 130
 131
 132 #ifndef readq
 133 static inline unsigned long long readq(void __iomem *addr)
 134 {
 135         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 136 }
 137 #endif
 138
 139 #ifndef writeq
 140 static inline void writeq(unsigned long long v, void __iomem *addr)
 141 {
 142         writel(v & 0xffffffff, addr);
 143         writel(v >> 32, addr + 4);
 144 }
 145 #endif
 146
 147 static irqreturn_t hpet_interrupt(int irq, void *data)
 148 {
 149         struct hpet_dev *devp;
 150         unsigned long isr;
 151
 152         devp = data;
 153         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 154
 155         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 156             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 157                 return IRQ_NONE;
 158
 159         spin_lock(&hpet_lock);
 160         devp->hd_irqdata++;
 161
 162         /*
 163          * For non-periodic timers, increment the accumulator.
 164          * This has the effect of treating non-periodic like periodic.
 165          */
 166         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 167                 unsigned long m, t;
 168
 169                 t = devp->hd_ireqfreq;
 170                 m = read_counter(&devp->hd_timer->hpet_compare);
 171                 write_counter(t + m, &devp->hd_timer->hpet_compare);
 172         }
 173
 174         if (devp->hd_flags & HPET_SHARED_IRQ)
 175                 writel(isr, &devp->hd_hpet->hpet_isr);
 176         spin_unlock(&hpet_lock);
 177
 178         wake_up_interruptible(&devp->hd_waitqueue);
 179
 180         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 181
 182         return IRQ_HANDLED;
 183 }
 184
 185 static void hpet_timer_set_irq(struct hpet_dev *devp)
 186 {
 187         unsigned long v;
 188         int irq, gsi;
 189         struct hpet_timer __iomem *timer;
 190
 191         spin_lock_irq(&hpet_lock);
 192         if (devp->hd_hdwirq) {
 193                 spin_unlock_irq(&hpet_lock);
 194                 return;
 195         }
 196
 197         timer = devp->hd_timer;
 198
 199         /* we prefer level triggered mode */
 200         v = readl(&timer->hpet_config);
 201         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
 202                 v |= Tn_INT_TYPE_CNF_MASK;
 203                 writel(v, &timer->hpet_config);
 204         }
 205         spin_unlock_irq(&hpet_lock);
 206
 207         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
 208                                  Tn_INT_ROUTE_CAP_SHIFT;
 209
 210         /*
 211          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
 212          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
 213          */
 214         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 215                 v &= ~0xf3df;
 216         else
 217                 v &= ~0xffff;
 218
 219         for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
 220                 if (irq >= nr_irqs) {
 221                         irq = HPET_MAX_IRQ;
 222                         break;
 223                 }
 224
 225                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
 226                                         ACPI_ACTIVE_LOW);
 227                 if (gsi > 0)
 228                         break;
 229
 230                 /* FIXME: Setup interrupt source table */
 231         }
 232
 233         if (irq < HPET_MAX_IRQ) {
 234                 spin_lock_irq(&hpet_lock);
 235                 v = readl(&timer->hpet_config);
 236                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 237                 writel(v, &timer->hpet_config);
 238                 devp->hd_hdwirq = gsi;
 239                 spin_unlock_irq(&hpet_lock);
 240         }
 241         return;
 242 }
 243
 244 static int hpet_open(struct inode *inode, struct file *file)
 245 {
 246         struct hpet_dev *devp;
 247         struct hpets *hpetp;
 248         int i;
 249
 250         if (file->f_mode & FMODE_WRITE)
 251                 return -EINVAL;
 252
 253         lock_kernel();
 254         spin_lock_irq(&hpet_lock);
 255
 256         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 257                 for (i = 0; i < hpetp->hp_ntimer; i++)
 258                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
 259                                 continue;
 260                         else {
 261                                 devp = &hpetp->hp_dev[i];
 262                                 break;
 263                         }
 264
 265         if (!devp) {
 266                 spin_unlock_irq(&hpet_lock);
 267                 unlock_kernel();
 268                 return -EBUSY;
 269         }
 270
 271         file->private_data = devp;
 272         devp->hd_irqdata = 0;
 273         devp->hd_flags |= HPET_OPEN;
 274         spin_unlock_irq(&hpet_lock);
 275         unlock_kernel();
 276
 277         hpet_timer_set_irq(devp);
 278
 279         return 0;
 280 }
 281
 282 static ssize_t
 283 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 284 {
 285         DECLARE_WAITQUEUE(wait, current);
 286         unsigned long data;
 287         ssize_t retval;
 288         struct hpet_dev *devp;
 289
 290         devp = file->private_data;
 291         if (!devp->hd_ireqfreq)
 292                 return -EIO;
 293
 294         if (count < sizeof(unsigned long))
 295                 return -EINVAL;
 296
 297         add_wait_queue(&devp->hd_waitqueue, &wait);
 298
 299         for ( ; ; ) {
 300                 set_current_state(TASK_INTERRUPTIBLE);
 301
 302                 spin_lock_irq(&hpet_lock);
 303                 data = devp->hd_irqdata;
 304                 devp->hd_irqdata = 0;
 305                 spin_unlock_irq(&hpet_lock);
 306
 307                 if (data)
 308                         break;
 309                 else if (file->f_flags & O_NONBLOCK) {
 310                         retval = -EAGAIN;
 311                         goto out;
 312                 } else if (signal_pending(current)) {
 313                         retval = -ERESTARTSYS;
 314                         goto out;
 315                 }
 316                 schedule();
 317         }
 318
 319         retval = put_user(data, (unsigned long __user *)buf);
 320         if (!retval)
 321                 retval = sizeof(unsigned long);
 322 out:
 323         __set_current_state(TASK_RUNNING);
 324         remove_wait_queue(&devp->hd_waitqueue, &wait);
 325
 326         return retval;
 327 }
 328
 329 static unsigned int hpet_poll(struct file *file, poll_table * wait)
 330 {
 331         unsigned long v;
 332         struct hpet_dev *devp;
 333
 334         devp = file->private_data;
 335
 336         if (!devp->hd_ireqfreq)
 337                 return 0;
 338
 339         poll_wait(file, &devp->hd_waitqueue, wait);
 340
 341         spin_lock_irq(&hpet_lock);
 342         v = devp->hd_irqdata;
 343         spin_unlock_irq(&hpet_lock);
 344
 345         if (v != 0)
 346                 return POLLIN | POLLRDNORM;
 347
 348         return 0;
 349 }
 350
 351 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 352 {
 353 #ifdef  CONFIG_HPET_MMAP
 354         struct hpet_dev *devp;
 355         unsigned long addr;
 356
 357         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
 358                 return -EINVAL;
 359
 360         devp = file->private_data;
 361         addr = devp->hd_hpets->hp_hpet_phys;
 362
 363         if (addr & (PAGE_SIZE - 1))
 364                 return -ENOSYS;
 365
 366         vma->vm_flags |= VM_IO;
 367         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 368
 369         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
 370                                         PAGE_SIZE, vma->vm_page_prot)) {
 371                 printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
 372                         __func__);
 373                 return -EAGAIN;
 374         }
 375
 376         return 0;
 377 #else
 378         return -ENOSYS;
 379 #endif
 380 }
 381
 382 static int hpet_fasync(int fd, struct file *file, int on)
 383 {
 384         struct hpet_dev *devp;
 385
 386         devp = file->private_data;
 387
 388         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 389                 return 0;
 390         else
 391                 return -EIO;
 392 }
 393
 394 static int hpet_release(struct inode *inode, struct file *file)
 395 {
 396         struct hpet_dev *devp;
 397         struct hpet_timer __iomem *timer;
 398         int irq = 0;
 399
 400         devp = file->private_data;
 401         timer = devp->hd_timer;
 402
 403         spin_lock_irq(&hpet_lock);
 404
 405         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 406                &timer->hpet_config);
 407
 408         irq = devp->hd_irq;
 409         devp->hd_irq = 0;
 410
 411         devp->hd_ireqfreq = 0;
 412
 413         if (devp->hd_flags & HPET_PERIODIC
 414             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 415                 unsigned long v;
 416
 417                 v = readq(&timer->hpet_config);
 418                 v ^= Tn_TYPE_CNF_MASK;
 419                 writeq(v, &timer->hpet_config);
 420         }
 421
 422         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 423         spin_unlock_irq(&hpet_lock);
 424
 425         if (irq)
 426                 free_irq(irq, devp);
 427
 428         file->private_data = NULL;
 429         return 0;
 430 }
 431
 432 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
 433
 434 static long hpet_ioctl(struct file *file, unsigned int cmd,
 435                         unsigned long arg)
 436 {
 437         struct hpet_dev *devp;
 438         int ret;
 439
 440         devp = file->private_data;
 441         lock_kernel();
 442         ret = hpet_ioctl_common(devp, cmd, arg, 0);
 443         unlock_kernel();
 444
 445         return ret;
 446 }
 447
 448 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 449 {
 450         struct hpet_timer __iomem *timer;
 451         struct hpet __iomem *hpet;
 452         struct hpets *hpetp;
 453         int irq;
 454         unsigned long g, v, t, m;
 455         unsigned long flags, isr;
 456
 457         timer = devp->hd_timer;
 458         hpet = devp->hd_hpet;
 459         hpetp = devp->hd_hpets;
 460
 461         if (!devp->hd_ireqfreq)
 462                 return -EIO;
 463
 464         spin_lock_irq(&hpet_lock);
 465
 466         if (devp->hd_flags & HPET_IE) {
 467                 spin_unlock_irq(&hpet_lock);
 468                 return -EBUSY;
 469         }
 470
 471         devp->hd_flags |= HPET_IE;
 472
 473         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 474                 devp->hd_flags |= HPET_SHARED_IRQ;
 475         spin_unlock_irq(&hpet_lock);
 476
 477         irq = devp->hd_hdwirq;
 478
 479         if (irq) {
 480                 unsigned long irq_flags;
 481
 482                 if (devp->hd_flags & HPET_SHARED_IRQ) {
 483                         /*
 484                          * To prevent the interrupt handler from seeing an
 485                          * unwanted interrupt status bit, program the timer
 486                          * so that it will not fire in the near future ...
 487                          */
 488                         writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
 489                                &timer->hpet_config);
 490                         write_counter(read_counter(&hpet->hpet_mc),
 491                                       &timer->hpet_compare);
 492                         /* ... and clear any left-over status. */
 493                         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 494                         writel(isr, &hpet->hpet_isr);
 495                 }
 496
 497                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 498                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 499                                                 ? IRQF_SHARED : IRQF_DISABLED;
 500                 if (request_irq(irq, hpet_interrupt, irq_flags,
 501                                 devp->hd_name, (void *)devp)) {
 502                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 503                         irq = 0;
 504                 }
 505         }
 506
 507         if (irq == 0) {
 508                 spin_lock_irq(&hpet_lock);
 509                 devp->hd_flags ^= HPET_IE;
 510                 spin_unlock_irq(&hpet_lock);
 511                 return -EIO;
 512         }
 513
 514         devp->hd_irq = irq;
 515         t = devp->hd_ireqfreq;
 516         v = readq(&timer->hpet_config);
 517
 518         /* 64-bit comparators are not yet supported through the ioctls,
 519          * so force this into 32-bit mode if it supports both modes
 520          */
 521         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 522
 523         if (devp->hd_flags & HPET_PERIODIC) {
 524                 g |= Tn_TYPE_CNF_MASK;
 525                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 526                 writeq(v, &timer->hpet_config);
 527                 local_irq_save(flags);
 528
 529                 /*
 530                  * NOTE: First we modify the hidden accumulator
 531                  * register supported by periodic-capable comparators.
 532                  * We never want to modify the (single) counter; that
 533                  * would affect all the comparators. The value written
 534                  * is the counter value when the first interrupt is due.
 535                  */
 536                 m = read_counter(&hpet->hpet_mc);
 537                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 538                 /*
 539                  * Then we modify the comparator, indicating the period
 540                  * for subsequent interrupt.
 541                  */
 542                 write_counter(t, &timer->hpet_compare);
 543         } else {
 544                 local_irq_save(flags);
 545                 m = read_counter(&hpet->hpet_mc);
 546                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 547         }
 548
 549         if (devp->hd_flags & HPET_SHARED_IRQ) {
 550                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 551                 writel(isr, &hpet->hpet_isr);
 552         }
 553         writeq(g, &timer->hpet_config);
 554         local_irq_restore(flags);
 555
 556         return 0;
 557 }
 558
 559 /* converts Hz to number of timer ticks */
 560 static inline unsigned long hpet_time_div(struct hpets *hpets,
 561                                           unsigned long dis)
 562 {
 563         unsigned long long m;
 564
 565         m = hpets->hp_tick_freq + (dis >> 1);
 566         do_div(m, dis);
 567         return (unsigned long)m;
 568 }
 569
 570 static int
 571 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
 572 {
 573         struct hpet_timer __iomem *timer;
 574         struct hpet __iomem *hpet;
 575         struct hpets *hpetp;
 576         int err;
 577         unsigned long v;
 578
 579         switch (cmd) {
 580         case HPET_IE_OFF:
 581         case HPET_INFO:
 582         case HPET_EPI:
 583         case HPET_DPI:
 584         case HPET_IRQFREQ:
 585                 timer = devp->hd_timer;
 586                 hpet = devp->hd_hpet;
 587                 hpetp = devp->hd_hpets;
 588                 break;
 589         case HPET_IE_ON:
 590                 return hpet_ioctl_ieon(devp);
 591         default:
 592                 return -EINVAL;
 593         }
 594
 595         err = 0;
 596
 597         switch (cmd) {
 598         case HPET_IE_OFF:
 599                 if ((devp->hd_flags & HPET_IE) == 0)
 600                         break;
 601                 v = readq(&timer->hpet_config);
 602                 v &= ~Tn_INT_ENB_CNF_MASK;
 603                 writeq(v, &timer->hpet_config);
 604                 if (devp->hd_irq) {
 605                         free_irq(devp->hd_irq, devp);
 606                         devp->hd_irq = 0;
 607                 }
 608                 devp->hd_flags ^= HPET_IE;
 609                 break;
 610         case HPET_INFO:
 611                 {
 612                         struct hpet_info info;
 613
 614                         if (devp->hd_ireqfreq)
 615                                 info.hi_ireqfreq =
 616                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 617                         else
 618                                 info.hi_ireqfreq = 0;
 619                         info.hi_flags =
 620                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 621                         info.hi_hpet = hpetp->hp_which;
 622                         info.hi_timer = devp - hpetp->hp_dev;
 623                         if (kernel)
 624                                 memcpy((void *)arg, &info, sizeof(info));
 625                         else
 626                                 if (copy_to_user((void __user *)arg, &info,
 627                                                  sizeof(info)))
 628                                         err = -EFAULT;
 629                         break;
 630                 }
 631         case HPET_EPI:
 632                 v = readq(&timer->hpet_config);
 633                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 634                         err = -ENXIO;
 635                         break;
 636                 }
 637                 devp->hd_flags |= HPET_PERIODIC;
 638                 break;
 639         case HPET_DPI:
 640                 v = readq(&timer->hpet_config);
 641                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 642                         err = -ENXIO;
 643                         break;
 644                 }
 645                 if (devp->hd_flags & HPET_PERIODIC &&
 646                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 647                         v = readq(&timer->hpet_config);
 648                         v ^= Tn_TYPE_CNF_MASK;
 649                         writeq(v, &timer->hpet_config);
 650                 }
 651                 devp->hd_flags &= ~HPET_PERIODIC;
 652                 break;
 653         case HPET_IRQFREQ:
 654                 if (!kernel && (arg > hpet_max_freq) &&
 655                     !capable(CAP_SYS_RESOURCE)) {
 656                         err = -EACCES;
 657                         break;
 658                 }
 659
 660                 if (!arg) {
 661                         err = -EINVAL;
 662                         break;
 663                 }
 664
 665                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 666         }
 667
 668         return err;
 669 }
 670
 671 static const struct file_operations hpet_fops = {
 672         .owner = THIS_MODULE,
 673         .llseek = no_llseek,
 674         .read = hpet_read,
 675         .poll = hpet_poll,
 676         .unlocked_ioctl = hpet_ioctl,
 677         .open = hpet_open,
 678         .release = hpet_release,
 679         .fasync = hpet_fasync,
 680         .mmap = hpet_mmap,
 681 };
 682
 683 static int hpet_is_known(struct hpet_data *hdp)
 684 {
 685         struct hpets *hpetp;
 686
 687         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 688                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 689                         return 1;
 690
 691         return 0;
 692 }
 693
 694 static ctl_table hpet_table[] = {
 695         {
 696          .procname = "max-user-freq",
 697          .data = &hpet_max_freq,
 698          .maxlen = sizeof(int),
 699          .mode = 0644,
 700          .proc_handler = proc_dointvec,
 701          },
 702         {}
 703 };
 704
 705 static ctl_table hpet_root[] = {
 706         {
 707          .procname = "hpet",
 708          .maxlen = 0,
 709          .mode = 0555,
 710          .child = hpet_table,
 711          },
 712         {}
 713 };
 714
 715 static ctl_table dev_root[] = {
 716         {
 717          .procname = "dev",
 718          .maxlen = 0,
 719          .mode = 0555,
 720          .child = hpet_root,
 721          },
 722         {}
 723 };
 724
 725 static struct ctl_table_header *sysctl_header;
 726
 727 /*
 728  * Adjustment for when arming the timer with
 729  * initial conditions.  That is, main counter
 730  * ticks expired before interrupts are enabled.
 731  */
 732 #define TICK_CALIBRATE  (1000UL)
 733
 734 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 735 {
 736         struct hpet_timer __iomem *timer = NULL;
 737         unsigned long t, m, count, i, flags, start;
 738         struct hpet_dev *devp;
 739         int j;
 740         struct hpet __iomem *hpet;
 741
 742         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 743                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 744                         timer = devp->hd_timer;
 745                         break;
 746                 }
 747
 748         if (!timer)
 749                 return 0;
 750
 751         hpet = hpetp->hp_hpet;
 752         t = read_counter(&timer->hpet_compare);
 753
 754         i = 0;
 755         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 756
 757         local_irq_save(flags);
 758
 759         start = read_counter(&hpet->hpet_mc);
 760
 761         do {
 762                 m = read_counter(&hpet->hpet_mc);
 763                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 764         } while (i++, (m - start) < count);
 765
 766         local_irq_restore(flags);
 767
 768         return (m - start) / i;
 769 }
 770
 771 static unsigned long hpet_calibrate(struct hpets *hpetp)
 772 {
 773         unsigned long ret = -1;
 774         unsigned long tmp;
 775
 776         /*
 777          * Try to calibrate until return value becomes stable small value.
 778          * If SMI interruption occurs in calibration loop, the return value
 779          * will be big. This avoids its impact.
 780          */
 781         for ( ; ; ) {
 782                 tmp = __hpet_calibrate(hpetp);
 783                 if (ret <= tmp)
 784                         break;
 785                 ret = tmp;
 786         }
 787
 788         return ret;
 789 }
 790
 791 int hpet_alloc(struct hpet_data *hdp)
 792 {
 793         u64 cap, mcfg;
 794         struct hpet_dev *devp;
 795         u32 i, ntimer;
 796         struct hpets *hpetp;
 797         size_t siz;
 798         struct hpet __iomem *hpet;
 799         static struct hpets *last = NULL;
 800         unsigned long period;
 801         unsigned long long temp;
 802         u32 remainder;
 803
 804         /*
 805          * hpet_alloc can be called by platform dependent code.
 806          * If platform dependent code has allocated the hpet that
 807          * ACPI has also reported, then we catch it here.
 808          */
 809         if (hpet_is_known(hdp)) {
 810                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 811                         __func__);
 812                 return 0;
 813         }
 814
 815         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 816                                       sizeof(struct hpet_dev));
 817
 818         hpetp = kzalloc(siz, GFP_KERNEL);
 819
 820         if (!hpetp)
 821                 return -ENOMEM;
 822
 823         hpetp->hp_which = hpet_nhpet++;
 824         hpetp->hp_hpet = hdp->hd_address;
 825         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 826
 827         hpetp->hp_ntimer = hdp->hd_nirqs;
 828
 829         for (i = 0; i < hdp->hd_nirqs; i++)
 830                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 831
 832         hpet = hpetp->hp_hpet;
 833
 834         cap = readq(&hpet->hpet_cap);
 835
 836         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 837
 838         if (hpetp->hp_ntimer != ntimer) {
 839                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 840                        " with number of timers\n");
 841                 kfree(hpetp);
 842                 return -ENODEV;
 843         }
 844
 845         if (last)
 846                 last->hp_next = hpetp;
 847         else
 848                 hpets = hpetp;
 849
 850         last = hpetp;
 851
 852         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 853                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 854         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 855         temp += period >> 1; /* round */
 856         do_div(temp, period);
 857         hpetp->hp_tick_freq = temp; /* ticks per second */
 858
 859         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 860                 hpetp->hp_which, hdp->hd_phys_address,
 861                 hpetp->hp_ntimer > 1 ? "s" : "");
 862         for (i = 0; i < hpetp->hp_ntimer; i++)
 863                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 864         printk("\n");
 865
 866         temp = hpetp->hp_tick_freq;
 867         remainder = do_div(temp, 1000000);
 868         printk(KERN_INFO
 869                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 870                 hpetp->hp_which, hpetp->hp_ntimer,
 871                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 872                 (unsigned) temp, remainder);
 873
 874         mcfg = readq(&hpet->hpet_config);
 875         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 876                 write_counter(0L, &hpet->hpet_mc);
 877                 mcfg |= HPET_ENABLE_CNF_MASK;
 878                 writeq(mcfg, &hpet->hpet_config);
 879         }
 880
 881         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 882                 struct hpet_timer __iomem *timer;
 883
 884                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 885
 886                 devp->hd_hpets = hpetp;
 887                 devp->hd_hpet = hpet;
 888                 devp->hd_timer = timer;
 889
 890                 /*
 891                  * If the timer was reserved by platform code,
 892                  * then make timer unavailable for opens.
 893                  */
 894                 if (hdp->hd_state & (1 << i)) {
 895                         devp->hd_flags = HPET_OPEN;
 896                         continue;
 897                 }
 898
 899                 init_waitqueue_head(&devp->hd_waitqueue);
 900         }
 901
 902         hpetp->hp_delta = hpet_calibrate(hpetp);
 903
 904 /* This clocksource driver currently only works on ia64 */
 905 #ifdef CONFIG_IA64
 906         if (!hpet_clocksource) {
 907                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 908                 CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
 909                 clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
 910                                                 clocksource_hpet.shift);
 911                 clocksource_register(&clocksource_hpet);
 912                 hpetp->hp_clocksource = &clocksource_hpet;
 913                 hpet_clocksource = &clocksource_hpet;
 914         }
 915 #endif
 916
 917         return 0;
 918 }
 919
 920 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 921 {
 922         struct hpet_data *hdp;
 923         acpi_status status;
 924         struct acpi_resource_address64 addr;
 925
 926         hdp = data;
 927
 928         status = acpi_resource_to_address64(res, &addr);
 929
 930         if (ACPI_SUCCESS(status)) {
 931                 hdp->hd_phys_address = addr.minimum;
 932                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 933
 934                 if (hpet_is_known(hdp)) {
 935                         iounmap(hdp->hd_address);
 936                         return AE_ALREADY_EXISTS;
 937                 }
 938         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 939                 struct acpi_resource_fixed_memory32 *fixmem32;
 940
 941                 fixmem32 = &res->data.fixed_memory32;
 942                 if (!fixmem32)
 943                         return AE_NO_MEMORY;
 944
 945                 hdp->hd_phys_address = fixmem32->address;
 946                 hdp->hd_address = ioremap(fixmem32->address,
 947                                                 HPET_RANGE_SIZE);
 948
 949                 if (hpet_is_known(hdp)) {
 950                         iounmap(hdp->hd_address);
 951                         return AE_ALREADY_EXISTS;
 952                 }
 953         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 954                 struct acpi_resource_extended_irq *irqp;
 955                 int i, irq;
 956
 957                 irqp = &res->data.extended_irq;
 958
 959                 for (i = 0; i < irqp->interrupt_count; i++) {
 960                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
 961                                       irqp->triggering, irqp->polarity);
 962                         if (irq < 0)
 963                                 return AE_ERROR;
 964
 965                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 966                         hdp->hd_nirqs++;
 967                 }
 968         }
 969
 970         return AE_OK;
 971 }
 972
 973 static int hpet_acpi_add(struct acpi_device *device)
 974 {
 975         acpi_status result;
 976         struct hpet_data data;
 977
 978         memset(&data, 0, sizeof(data));
 979
 980         result =
 981             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 982                                 hpet_resources, &data);
 983
 984         if (ACPI_FAILURE(result))
 985                 return -ENODEV;
 986
 987         if (!data.hd_address || !data.hd_nirqs) {
 988                 if (data.hd_address)
 989                         iounmap(data.hd_address);
 990                 printk("%s: no address or irqs in _CRS\n", __func__);
 991                 return -ENODEV;
 992         }
 993
 994         return hpet_alloc(&data);
 995 }
 996
 997 static int hpet_acpi_remove(struct acpi_device *device, int type)
 998 {
 999         /* XXX need to unregister clocksource, dealloc mem, etc */
1000         return -EINVAL;
1001 }
1002
1003 static const struct acpi_device_id hpet_device_ids[] = {
1004         {"PNP0103", 0},
1005         {"", 0},
1006 };
1007 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
1008
1009 static struct acpi_driver hpet_acpi_driver = {
1010         .name = "hpet",
1011         .ids = hpet_device_ids,
1012         .ops = {
1013                 .add = hpet_acpi_add,
1014                 .remove = hpet_acpi_remove,
1015                 },
1016 };
1017
1018 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1019
1020 static int __init hpet_init(void)
1021 {
1022         int result;
1023
1024         result = misc_register(&hpet_misc);
1025         if (result < 0)
1026                 return -ENODEV;
1027
1028         sysctl_header = register_sysctl_table(dev_root);
1029
1030         result = acpi_bus_register_driver(&hpet_acpi_driver);
1031         if (result < 0) {
1032                 if (sysctl_header)
1033                         unregister_sysctl_table(sysctl_header);
1034                 misc_deregister(&hpet_misc);
1035                 return result;
1036         }
1037
1038         return 0;
1039 }
1040
1041 static void __exit hpet_exit(void)
1042 {
1043         acpi_bus_unregister_driver(&hpet_acpi_driver);
1044
1045         if (sysctl_header)
1046                 unregister_sysctl_table(sysctl_header);
1047         misc_deregister(&hpet_misc);
1048
1049         return;
1050 }
1051
1052 module_init(hpet_init);
1053 module_exit(hpet_exit);
1054 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1055 MODULE_LICENSE("GPL");