drivers/char/hpet.c

   1 /*
   2  * Intel & MS High Precision Event Timer Implementation.
   3  *
   4  * Copyright (C) 2003 Intel Corporation
   5  *      Venki Pallipadi
   6  * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
   7  *      Bob Picco <robert.picco@hp.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/interrupt.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/types.h>
  19 #include <linux/miscdevice.h>
  20 #include <linux/major.h>
  21 #include <linux/ioport.h>
  22 #include <linux/fcntl.h>
  23 #include <linux/init.h>
  24 #include <linux/poll.h>
  25 #include <linux/mm.h>
  26 #include <linux/proc_fs.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/sysctl.h>
  29 #include <linux/wait.h>
  30 #include <linux/bcd.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/bitops.h>
  33 #include <linux/clocksource.h>
  34
  35 #include <asm/current.h>
  36 #include <asm/uaccess.h>
  37 #include <asm/system.h>
  38 #include <asm/io.h>
  39 #include <asm/irq.h>
  40 #include <asm/div64.h>
  41
  42 #include <linux/acpi.h>
  43 #include <acpi/acpi_bus.h>
  44 #include <linux/hpet.h>
  45
  46 /*
  47  * The High Precision Event Timer driver.
  48  * This driver is closely modelled after the rtc.c driver.
  49  * http://www.intel.com/hardwaredesign/hpetspec_1.pdf
  50  */
  51 #define HPET_USER_FREQ  (64)
  52 #define HPET_DRIFT      (500)
  53
  54 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
  55
  56
  57 /* WARNING -- don't get confused.  These macros are never used
  58  * to write the (single) counter, and rarely to read it.
  59  * They're badly named; to fix, someday.
  60  */
  61 #if BITS_PER_LONG == 64
  62 #define write_counter(V, MC)    writeq(V, MC)
  63 #define read_counter(MC)        readq(MC)
  64 #else
  65 #define write_counter(V, MC)    writel(V, MC)
  66 #define read_counter(MC)        readl(MC)
  67 #endif
  68
  69 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  70
  71 /* This clocksource driver currently only works on ia64 */
  72 #ifdef CONFIG_IA64
  73 static void __iomem *hpet_mctr;
  74
  75 static cycle_t read_hpet(struct clocksource *cs)
  76 {
  77         return (cycle_t)read_counter((void __iomem *)hpet_mctr);
  78 }
  79
  80 static struct clocksource clocksource_hpet = {
  81         .name           = "hpet",
  82         .rating         = 250,
  83         .read           = read_hpet,
  84         .mask           = CLOCKSOURCE_MASK(64),
  85         .mult           = 0, /* to be calculated */
  86         .shift          = 10,
  87         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  88 };
  89 static struct clocksource *hpet_clocksource;
  90 #endif
  91
  92 /* A lock for concurrent access by app and isr hpet activity. */
  93 static DEFINE_SPINLOCK(hpet_lock);
  94
  95 #define HPET_DEV_NAME   (7)
  96
  97 struct hpet_dev {
  98         struct hpets *hd_hpets;
  99         struct hpet __iomem *hd_hpet;
 100         struct hpet_timer __iomem *hd_timer;
 101         unsigned long hd_ireqfreq;
 102         unsigned long hd_irqdata;
 103         wait_queue_head_t hd_waitqueue;
 104         struct fasync_struct *hd_async_queue;
 105         unsigned int hd_flags;
 106         unsigned int hd_irq;
 107         unsigned int hd_hdwirq;
 108         char hd_name[HPET_DEV_NAME];
 109 };
 110
 111 struct hpets {
 112         struct hpets *hp_next;
 113         struct hpet __iomem *hp_hpet;
 114         unsigned long hp_hpet_phys;
 115         struct clocksource *hp_clocksource;
 116         unsigned long long hp_tick_freq;
 117         unsigned long hp_delta;
 118         unsigned int hp_ntimer;
 119         unsigned int hp_which;
 120         struct hpet_dev hp_dev[1];
 121 };
 122
 123 static struct hpets *hpets;
 124
 125 #define HPET_OPEN               0x0001
 126 #define HPET_IE                 0x0002  /* interrupt enabled */
 127 #define HPET_PERIODIC           0x0004
 128 #define HPET_SHARED_IRQ         0x0008
 129
 130
 131 #ifndef readq
 132 static inline unsigned long long readq(void __iomem *addr)
 133 {
 134         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 135 }
 136 #endif
 137
 138 #ifndef writeq
 139 static inline void writeq(unsigned long long v, void __iomem *addr)
 140 {
 141         writel(v & 0xffffffff, addr);
 142         writel(v >> 32, addr + 4);
 143 }
 144 #endif
 145
 146 static irqreturn_t hpet_interrupt(int irq, void *data)
 147 {
 148         struct hpet_dev *devp;
 149         unsigned long isr;
 150
 151         devp = data;
 152         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 153
 154         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 155             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 156                 return IRQ_NONE;
 157
 158         spin_lock(&hpet_lock);
 159         devp->hd_irqdata++;
 160
 161         /*
 162          * For non-periodic timers, increment the accumulator.
 163          * This has the effect of treating non-periodic like periodic.
 164          */
 165         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 166                 unsigned long m, t;
 167
 168                 t = devp->hd_ireqfreq;
 169                 m = read_counter(&devp->hd_timer->hpet_compare);
 170                 write_counter(t + m, &devp->hd_timer->hpet_compare);
 171         }
 172
 173         if (devp->hd_flags & HPET_SHARED_IRQ)
 174                 writel(isr, &devp->hd_hpet->hpet_isr);
 175         spin_unlock(&hpet_lock);
 176
 177         wake_up_interruptible(&devp->hd_waitqueue);
 178
 179         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 180
 181         return IRQ_HANDLED;
 182 }
 183
 184 static void hpet_timer_set_irq(struct hpet_dev *devp)
 185 {
 186         unsigned long v;
 187         int irq, gsi;
 188         struct hpet_timer __iomem *timer;
 189
 190         spin_lock_irq(&hpet_lock);
 191         if (devp->hd_hdwirq) {
 192                 spin_unlock_irq(&hpet_lock);
 193                 return;
 194         }
 195
 196         timer = devp->hd_timer;
 197
 198         /* we prefer level triggered mode */
 199         v = readl(&timer->hpet_config);
 200         if (!(v & Tn_INT_TYPE_CNF_MASK)) {
 201                 v |= Tn_INT_TYPE_CNF_MASK;
 202                 writel(v, &timer->hpet_config);
 203         }
 204         spin_unlock_irq(&hpet_lock);
 205
 206         v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
 207                                  Tn_INT_ROUTE_CAP_SHIFT;
 208
 209         /*
 210          * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
 211          * legacy device. In IO APIC mode, we skip all the legacy IRQS.
 212          */
 213         if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 214                 v &= ~0xf3df;
 215         else
 216                 v &= ~0xffff;
 217
 218         for (irq = find_first_bit(&v, HPET_MAX_IRQ); irq < HPET_MAX_IRQ;
 219                 irq = find_next_bit(&v, HPET_MAX_IRQ, 1 + irq)) {
 220
 221                 if (irq >= nr_irqs) {
 222                         irq = HPET_MAX_IRQ;
 223                         break;
 224                 }
 225
 226                 gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
 227                                         ACPI_ACTIVE_LOW);
 228                 if (gsi > 0)
 229                         break;
 230
 231                 /* FIXME: Setup interrupt source table */
 232         }
 233
 234         if (irq < HPET_MAX_IRQ) {
 235                 spin_lock_irq(&hpet_lock);
 236                 v = readl(&timer->hpet_config);
 237                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 238                 writel(v, &timer->hpet_config);
 239                 devp->hd_hdwirq = gsi;
 240                 spin_unlock_irq(&hpet_lock);
 241         }
 242         return;
 243 }
 244
 245 static int hpet_open(struct inode *inode, struct file *file)
 246 {
 247         struct hpet_dev *devp;
 248         struct hpets *hpetp;
 249         int i;
 250
 251         if (file->f_mode & FMODE_WRITE)
 252                 return -EINVAL;
 253
 254         lock_kernel();
 255         spin_lock_irq(&hpet_lock);
 256
 257         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 258                 for (i = 0; i < hpetp->hp_ntimer; i++)
 259                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
 260                                 continue;
 261                         else {
 262                                 devp = &hpetp->hp_dev[i];
 263                                 break;
 264                         }
 265
 266         if (!devp) {
 267                 spin_unlock_irq(&hpet_lock);
 268                 unlock_kernel();
 269                 return -EBUSY;
 270         }
 271
 272         file->private_data = devp;
 273         devp->hd_irqdata = 0;
 274         devp->hd_flags |= HPET_OPEN;
 275         spin_unlock_irq(&hpet_lock);
 276         unlock_kernel();
 277
 278         hpet_timer_set_irq(devp);
 279
 280         return 0;
 281 }
 282
 283 static ssize_t
 284 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 285 {
 286         DECLARE_WAITQUEUE(wait, current);
 287         unsigned long data;
 288         ssize_t retval;
 289         struct hpet_dev *devp;
 290
 291         devp = file->private_data;
 292         if (!devp->hd_ireqfreq)
 293                 return -EIO;
 294
 295         if (count < sizeof(unsigned long))
 296                 return -EINVAL;
 297
 298         add_wait_queue(&devp->hd_waitqueue, &wait);
 299
 300         for ( ; ; ) {
 301                 set_current_state(TASK_INTERRUPTIBLE);
 302
 303                 spin_lock_irq(&hpet_lock);
 304                 data = devp->hd_irqdata;
 305                 devp->hd_irqdata = 0;
 306                 spin_unlock_irq(&hpet_lock);
 307
 308                 if (data)
 309                         break;
 310                 else if (file->f_flags & O_NONBLOCK) {
 311                         retval = -EAGAIN;
 312                         goto out;
 313                 } else if (signal_pending(current)) {
 314                         retval = -ERESTARTSYS;
 315                         goto out;
 316                 }
 317                 schedule();
 318         }
 319
 320         retval = put_user(data, (unsigned long __user *)buf);
 321         if (!retval)
 322                 retval = sizeof(unsigned long);
 323 out:
 324         __set_current_state(TASK_RUNNING);
 325         remove_wait_queue(&devp->hd_waitqueue, &wait);
 326
 327         return retval;
 328 }
 329
 330 static unsigned int hpet_poll(struct file *file, poll_table * wait)
 331 {
 332         unsigned long v;
 333         struct hpet_dev *devp;
 334
 335         devp = file->private_data;
 336
 337         if (!devp->hd_ireqfreq)
 338                 return 0;
 339
 340         poll_wait(file, &devp->hd_waitqueue, wait);
 341
 342         spin_lock_irq(&hpet_lock);
 343         v = devp->hd_irqdata;
 344         spin_unlock_irq(&hpet_lock);
 345
 346         if (v != 0)
 347                 return POLLIN | POLLRDNORM;
 348
 349         return 0;
 350 }
 351
 352 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 353 {
 354 #ifdef  CONFIG_HPET_MMAP
 355         struct hpet_dev *devp;
 356         unsigned long addr;
 357
 358         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
 359                 return -EINVAL;
 360
 361         devp = file->private_data;
 362         addr = devp->hd_hpets->hp_hpet_phys;
 363
 364         if (addr & (PAGE_SIZE - 1))
 365                 return -ENOSYS;
 366
 367         vma->vm_flags |= VM_IO;
 368         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 369
 370         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
 371                                         PAGE_SIZE, vma->vm_page_prot)) {
 372                 printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
 373                         __func__);
 374                 return -EAGAIN;
 375         }
 376
 377         return 0;
 378 #else
 379         return -ENOSYS;
 380 #endif
 381 }
 382
 383 static int hpet_fasync(int fd, struct file *file, int on)
 384 {
 385         struct hpet_dev *devp;
 386
 387         devp = file->private_data;
 388
 389         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 390                 return 0;
 391         else
 392                 return -EIO;
 393 }
 394
 395 static int hpet_release(struct inode *inode, struct file *file)
 396 {
 397         struct hpet_dev *devp;
 398         struct hpet_timer __iomem *timer;
 399         int irq = 0;
 400
 401         devp = file->private_data;
 402         timer = devp->hd_timer;
 403
 404         spin_lock_irq(&hpet_lock);
 405
 406         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 407                &timer->hpet_config);
 408
 409         irq = devp->hd_irq;
 410         devp->hd_irq = 0;
 411
 412         devp->hd_ireqfreq = 0;
 413
 414         if (devp->hd_flags & HPET_PERIODIC
 415             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 416                 unsigned long v;
 417
 418                 v = readq(&timer->hpet_config);
 419                 v ^= Tn_TYPE_CNF_MASK;
 420                 writeq(v, &timer->hpet_config);
 421         }
 422
 423         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 424         spin_unlock_irq(&hpet_lock);
 425
 426         if (irq)
 427                 free_irq(irq, devp);
 428
 429         file->private_data = NULL;
 430         return 0;
 431 }
 432
 433 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
 434
 435 static int
 436 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 437            unsigned long arg)
 438 {
 439         struct hpet_dev *devp;
 440
 441         devp = file->private_data;
 442         return hpet_ioctl_common(devp, cmd, arg, 0);
 443 }
 444
 445 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 446 {
 447         struct hpet_timer __iomem *timer;
 448         struct hpet __iomem *hpet;
 449         struct hpets *hpetp;
 450         int irq;
 451         unsigned long g, v, t, m;
 452         unsigned long flags, isr;
 453
 454         timer = devp->hd_timer;
 455         hpet = devp->hd_hpet;
 456         hpetp = devp->hd_hpets;
 457
 458         if (!devp->hd_ireqfreq)
 459                 return -EIO;
 460
 461         spin_lock_irq(&hpet_lock);
 462
 463         if (devp->hd_flags & HPET_IE) {
 464                 spin_unlock_irq(&hpet_lock);
 465                 return -EBUSY;
 466         }
 467
 468         devp->hd_flags |= HPET_IE;
 469
 470         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 471                 devp->hd_flags |= HPET_SHARED_IRQ;
 472         spin_unlock_irq(&hpet_lock);
 473
 474         irq = devp->hd_hdwirq;
 475
 476         if (irq) {
 477                 unsigned long irq_flags;
 478
 479                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 480                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 481                                                 ? IRQF_SHARED : IRQF_DISABLED;
 482                 if (request_irq(irq, hpet_interrupt, irq_flags,
 483                                 devp->hd_name, (void *)devp)) {
 484                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 485                         irq = 0;
 486                 }
 487         }
 488
 489         if (irq == 0) {
 490                 spin_lock_irq(&hpet_lock);
 491                 devp->hd_flags ^= HPET_IE;
 492                 spin_unlock_irq(&hpet_lock);
 493                 return -EIO;
 494         }
 495
 496         devp->hd_irq = irq;
 497         t = devp->hd_ireqfreq;
 498         v = readq(&timer->hpet_config);
 499
 500         /* 64-bit comparators are not yet supported through the ioctls,
 501          * so force this into 32-bit mode if it supports both modes
 502          */
 503         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 504
 505         if (devp->hd_flags & HPET_PERIODIC) {
 506                 g |= Tn_TYPE_CNF_MASK;
 507                 v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
 508                 writeq(v, &timer->hpet_config);
 509                 local_irq_save(flags);
 510
 511                 /*
 512                  * NOTE: First we modify the hidden accumulator
 513                  * register supported by periodic-capable comparators.
 514                  * We never want to modify the (single) counter; that
 515                  * would affect all the comparators. The value written
 516                  * is the counter value when the first interrupt is due.
 517                  */
 518                 m = read_counter(&hpet->hpet_mc);
 519                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 520                 /*
 521                  * Then we modify the comparator, indicating the period
 522                  * for subsequent interrupt.
 523                  */
 524                 write_counter(t, &timer->hpet_compare);
 525         } else {
 526                 local_irq_save(flags);
 527                 m = read_counter(&hpet->hpet_mc);
 528                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 529         }
 530
 531         if (devp->hd_flags & HPET_SHARED_IRQ) {
 532                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 533                 writel(isr, &hpet->hpet_isr);
 534         }
 535         writeq(g, &timer->hpet_config);
 536         local_irq_restore(flags);
 537
 538         return 0;
 539 }
 540
 541 /* converts Hz to number of timer ticks */
 542 static inline unsigned long hpet_time_div(struct hpets *hpets,
 543                                           unsigned long dis)
 544 {
 545         unsigned long long m;
 546
 547         m = hpets->hp_tick_freq + (dis >> 1);
 548         do_div(m, dis);
 549         return (unsigned long)m;
 550 }
 551
 552 static int
 553 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
 554 {
 555         struct hpet_timer __iomem *timer;
 556         struct hpet __iomem *hpet;
 557         struct hpets *hpetp;
 558         int err;
 559         unsigned long v;
 560
 561         switch (cmd) {
 562         case HPET_IE_OFF:
 563         case HPET_INFO:
 564         case HPET_EPI:
 565         case HPET_DPI:
 566         case HPET_IRQFREQ:
 567                 timer = devp->hd_timer;
 568                 hpet = devp->hd_hpet;
 569                 hpetp = devp->hd_hpets;
 570                 break;
 571         case HPET_IE_ON:
 572                 return hpet_ioctl_ieon(devp);
 573         default:
 574                 return -EINVAL;
 575         }
 576
 577         err = 0;
 578
 579         switch (cmd) {
 580         case HPET_IE_OFF:
 581                 if ((devp->hd_flags & HPET_IE) == 0)
 582                         break;
 583                 v = readq(&timer->hpet_config);
 584                 v &= ~Tn_INT_ENB_CNF_MASK;
 585                 writeq(v, &timer->hpet_config);
 586                 if (devp->hd_irq) {
 587                         free_irq(devp->hd_irq, devp);
 588                         devp->hd_irq = 0;
 589                 }
 590                 devp->hd_flags ^= HPET_IE;
 591                 break;
 592         case HPET_INFO:
 593                 {
 594                         struct hpet_info info;
 595
 596                         if (devp->hd_ireqfreq)
 597                                 info.hi_ireqfreq =
 598                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 599                         else
 600                                 info.hi_ireqfreq = 0;
 601                         info.hi_flags =
 602                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 603                         info.hi_hpet = hpetp->hp_which;
 604                         info.hi_timer = devp - hpetp->hp_dev;
 605                         if (kernel)
 606                                 memcpy((void *)arg, &info, sizeof(info));
 607                         else
 608                                 if (copy_to_user((void __user *)arg, &info,
 609                                                  sizeof(info)))
 610                                         err = -EFAULT;
 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 (!kernel && (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 const struct file_operations hpet_fops = {
 654         .owner = THIS_MODULE,
 655         .llseek = no_llseek,
 656         .read = hpet_read,
 657         .poll = hpet_poll,
 658         .ioctl = hpet_ioctl,
 659         .open = hpet_open,
 660         .release = hpet_release,
 661         .fasync = hpet_fasync,
 662         .mmap = hpet_mmap,
 663 };
 664
 665 static int hpet_is_known(struct hpet_data *hdp)
 666 {
 667         struct hpets *hpetp;
 668
 669         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 670                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 671                         return 1;
 672
 673         return 0;
 674 }
 675
 676 static ctl_table hpet_table[] = {
 677         {
 678          .ctl_name = CTL_UNNUMBERED,
 679          .procname = "max-user-freq",
 680          .data = &hpet_max_freq,
 681          .maxlen = sizeof(int),
 682          .mode = 0644,
 683          .proc_handler = &proc_dointvec,
 684          },
 685         {.ctl_name = 0}
 686 };
 687
 688 static ctl_table hpet_root[] = {
 689         {
 690          .ctl_name = CTL_UNNUMBERED,
 691          .procname = "hpet",
 692          .maxlen = 0,
 693          .mode = 0555,
 694          .child = hpet_table,
 695          },
 696         {.ctl_name = 0}
 697 };
 698
 699 static ctl_table dev_root[] = {
 700         {
 701          .ctl_name = CTL_DEV,
 702          .procname = "dev",
 703          .maxlen = 0,
 704          .mode = 0555,
 705          .child = hpet_root,
 706          },
 707         {.ctl_name = 0}
 708 };
 709
 710 static struct ctl_table_header *sysctl_header;
 711
 712 /*
 713  * Adjustment for when arming the timer with
 714  * initial conditions.  That is, main counter
 715  * ticks expired before interrupts are enabled.
 716  */
 717 #define TICK_CALIBRATE  (1000UL)
 718
 719 static unsigned long __hpet_calibrate(struct hpets *hpetp)
 720 {
 721         struct hpet_timer __iomem *timer = NULL;
 722         unsigned long t, m, count, i, flags, start;
 723         struct hpet_dev *devp;
 724         int j;
 725         struct hpet __iomem *hpet;
 726
 727         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 728                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 729                         timer = devp->hd_timer;
 730                         break;
 731                 }
 732
 733         if (!timer)
 734                 return 0;
 735
 736         hpet = hpetp->hp_hpet;
 737         t = read_counter(&timer->hpet_compare);
 738
 739         i = 0;
 740         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 741
 742         local_irq_save(flags);
 743
 744         start = read_counter(&hpet->hpet_mc);
 745
 746         do {
 747                 m = read_counter(&hpet->hpet_mc);
 748                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 749         } while (i++, (m - start) < count);
 750
 751         local_irq_restore(flags);
 752
 753         return (m - start) / i;
 754 }
 755
 756 static unsigned long hpet_calibrate(struct hpets *hpetp)
 757 {
 758         unsigned long ret = -1;
 759         unsigned long tmp;
 760
 761         /*
 762          * Try to calibrate until return value becomes stable small value.
 763          * If SMI interruption occurs in calibration loop, the return value
 764          * will be big. This avoids its impact.
 765          */
 766         for ( ; ; ) {
 767                 tmp = __hpet_calibrate(hpetp);
 768                 if (ret <= tmp)
 769                         break;
 770                 ret = tmp;
 771         }
 772
 773         return ret;
 774 }
 775
 776 int hpet_alloc(struct hpet_data *hdp)
 777 {
 778         u64 cap, mcfg;
 779         struct hpet_dev *devp;
 780         u32 i, ntimer;
 781         struct hpets *hpetp;
 782         size_t siz;
 783         struct hpet __iomem *hpet;
 784         static struct hpets *last = NULL;
 785         unsigned long period;
 786         unsigned long long temp;
 787         u32 remainder;
 788
 789         /*
 790          * hpet_alloc can be called by platform dependent code.
 791          * If platform dependent code has allocated the hpet that
 792          * ACPI has also reported, then we catch it here.
 793          */
 794         if (hpet_is_known(hdp)) {
 795                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 796                         __func__);
 797                 return 0;
 798         }
 799
 800         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 801                                       sizeof(struct hpet_dev));
 802
 803         hpetp = kzalloc(siz, GFP_KERNEL);
 804
 805         if (!hpetp)
 806                 return -ENOMEM;
 807
 808         hpetp->hp_which = hpet_nhpet++;
 809         hpetp->hp_hpet = hdp->hd_address;
 810         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 811
 812         hpetp->hp_ntimer = hdp->hd_nirqs;
 813
 814         for (i = 0; i < hdp->hd_nirqs; i++)
 815                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 816
 817         hpet = hpetp->hp_hpet;
 818
 819         cap = readq(&hpet->hpet_cap);
 820
 821         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 822
 823         if (hpetp->hp_ntimer != ntimer) {
 824                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 825                        " with number of timers\n");
 826                 kfree(hpetp);
 827                 return -ENODEV;
 828         }
 829
 830         if (last)
 831                 last->hp_next = hpetp;
 832         else
 833                 hpets = hpetp;
 834
 835         last = hpetp;
 836
 837         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 838                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 839         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 840         temp += period >> 1; /* round */
 841         do_div(temp, period);
 842         hpetp->hp_tick_freq = temp; /* ticks per second */
 843
 844         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 845                 hpetp->hp_which, hdp->hd_phys_address,
 846                 hpetp->hp_ntimer > 1 ? "s" : "");
 847         for (i = 0; i < hpetp->hp_ntimer; i++)
 848                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 849         printk("\n");
 850
 851         temp = hpetp->hp_tick_freq;
 852         remainder = do_div(temp, 1000000);
 853         printk(KERN_INFO
 854                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 855                 hpetp->hp_which, hpetp->hp_ntimer,
 856                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 857                 (unsigned) temp, remainder);
 858
 859         mcfg = readq(&hpet->hpet_config);
 860         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 861                 write_counter(0L, &hpet->hpet_mc);
 862                 mcfg |= HPET_ENABLE_CNF_MASK;
 863                 writeq(mcfg, &hpet->hpet_config);
 864         }
 865
 866         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 867                 struct hpet_timer __iomem *timer;
 868
 869                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 870
 871                 devp->hd_hpets = hpetp;
 872                 devp->hd_hpet = hpet;
 873                 devp->hd_timer = timer;
 874
 875                 /*
 876                  * If the timer was reserved by platform code,
 877                  * then make timer unavailable for opens.
 878                  */
 879                 if (hdp->hd_state & (1 << i)) {
 880                         devp->hd_flags = HPET_OPEN;
 881                         continue;
 882                 }
 883
 884                 init_waitqueue_head(&devp->hd_waitqueue);
 885         }
 886
 887         hpetp->hp_delta = hpet_calibrate(hpetp);
 888
 889 /* This clocksource driver currently only works on ia64 */
 890 #ifdef CONFIG_IA64
 891         if (!hpet_clocksource) {
 892                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 893                 CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
 894                 clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
 895                                                 clocksource_hpet.shift);
 896                 clocksource_register(&clocksource_hpet);
 897                 hpetp->hp_clocksource = &clocksource_hpet;
 898                 hpet_clocksource = &clocksource_hpet;
 899         }
 900 #endif
 901
 902         return 0;
 903 }
 904
 905 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 906 {
 907         struct hpet_data *hdp;
 908         acpi_status status;
 909         struct acpi_resource_address64 addr;
 910
 911         hdp = data;
 912
 913         status = acpi_resource_to_address64(res, &addr);
 914
 915         if (ACPI_SUCCESS(status)) {
 916                 hdp->hd_phys_address = addr.minimum;
 917                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 918
 919                 if (hpet_is_known(hdp)) {
 920                         iounmap(hdp->hd_address);
 921                         return AE_ALREADY_EXISTS;
 922                 }
 923         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 924                 struct acpi_resource_fixed_memory32 *fixmem32;
 925
 926                 fixmem32 = &res->data.fixed_memory32;
 927                 if (!fixmem32)
 928                         return AE_NO_MEMORY;
 929
 930                 hdp->hd_phys_address = fixmem32->address;
 931                 hdp->hd_address = ioremap(fixmem32->address,
 932                                                 HPET_RANGE_SIZE);
 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_EXTENDED_IRQ) {
 939                 struct acpi_resource_extended_irq *irqp;
 940                 int i, irq;
 941
 942                 irqp = &res->data.extended_irq;
 943
 944                 for (i = 0; i < irqp->interrupt_count; i++) {
 945                         irq = acpi_register_gsi(NULL, irqp->interrupts[i],
 946                                       irqp->triggering, irqp->polarity);
 947                         if (irq < 0)
 948                                 return AE_ERROR;
 949
 950                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 951                         hdp->hd_nirqs++;
 952                 }
 953         }
 954
 955         return AE_OK;
 956 }
 957
 958 static int hpet_acpi_add(struct acpi_device *device)
 959 {
 960         acpi_status result;
 961         struct hpet_data data;
 962
 963         memset(&data, 0, sizeof(data));
 964
 965         result =
 966             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 967                                 hpet_resources, &data);
 968
 969         if (ACPI_FAILURE(result))
 970                 return -ENODEV;
 971
 972         if (!data.hd_address || !data.hd_nirqs) {
 973                 printk("%s: no address or irqs in _CRS\n", __func__);
 974                 return -ENODEV;
 975         }
 976
 977         return hpet_alloc(&data);
 978 }
 979
 980 static int hpet_acpi_remove(struct acpi_device *device, int type)
 981 {
 982         /* XXX need to unregister clocksource, dealloc mem, etc */
 983         return -EINVAL;
 984 }
 985
 986 static const struct acpi_device_id hpet_device_ids[] = {
 987         {"PNP0103", 0},
 988         {"", 0},
 989 };
 990 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
 991
 992 static struct acpi_driver hpet_acpi_driver = {
 993         .name = "hpet",
 994         .ids = hpet_device_ids,
 995         .ops = {
 996                 .add = hpet_acpi_add,
 997                 .remove = hpet_acpi_remove,
 998                 },
 999 };
1000
1001 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
1002
1003 static int __init hpet_init(void)
1004 {
1005         int result;
1006
1007         result = misc_register(&hpet_misc);
1008         if (result < 0)
1009                 return -ENODEV;
1010
1011         sysctl_header = register_sysctl_table(dev_root);
1012
1013         result = acpi_bus_register_driver(&hpet_acpi_driver);
1014         if (result < 0) {
1015                 if (sysctl_header)
1016                         unregister_sysctl_table(sysctl_header);
1017                 misc_deregister(&hpet_misc);
1018                 return result;
1019         }
1020
1021         return 0;
1022 }
1023
1024 static void __exit hpet_exit(void)
1025 {
1026         acpi_bus_unregister_driver(&hpet_acpi_driver);
1027
1028         if (sysctl_header)
1029                 unregister_sysctl_table(sysctl_header);
1030         misc_deregister(&hpet_misc);
1031
1032         return;
1033 }
1034
1035 module_init(hpet_init);
1036 module_exit(hpet_exit);
1037 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1038 MODULE_LICENSE("GPL");