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.htm
  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(void)
  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_hpet->hpet_mc);
 170                 write_counter(t + m + devp->hd_hpets->hp_delta,
 171                               &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 (irq = find_first_bit(&v, HPET_MAX_IRQ); irq < HPET_MAX_IRQ;
 220                 irq = find_next_bit(&v, HPET_MAX_IRQ, 1 + irq)) {
 221
 222                 if (irq >= nr_irqs) {
 223                         irq = HPET_MAX_IRQ;
 224                         break;
 225                 }
 226
 227                 gsi = acpi_register_gsi(irq, ACPI_LEVEL_SENSITIVE,
 228                                         ACPI_ACTIVE_LOW);
 229                 if (gsi > 0)
 230                         break;
 231
 232                 /* FIXME: Setup interrupt source table */
 233         }
 234
 235         if (irq < HPET_MAX_IRQ) {
 236                 spin_lock_irq(&hpet_lock);
 237                 v = readl(&timer->hpet_config);
 238                 v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 239                 writel(v, &timer->hpet_config);
 240                 devp->hd_hdwirq = gsi;
 241                 spin_unlock_irq(&hpet_lock);
 242         }
 243         return;
 244 }
 245
 246 static int hpet_open(struct inode *inode, struct file *file)
 247 {
 248         struct hpet_dev *devp;
 249         struct hpets *hpetp;
 250         int i;
 251
 252         if (file->f_mode & FMODE_WRITE)
 253                 return -EINVAL;
 254
 255         lock_kernel();
 256         spin_lock_irq(&hpet_lock);
 257
 258         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 259                 for (i = 0; i < hpetp->hp_ntimer; i++)
 260                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN)
 261                                 continue;
 262                         else {
 263                                 devp = &hpetp->hp_dev[i];
 264                                 break;
 265                         }
 266
 267         if (!devp) {
 268                 spin_unlock_irq(&hpet_lock);
 269                 unlock_kernel();
 270                 return -EBUSY;
 271         }
 272
 273         file->private_data = devp;
 274         devp->hd_irqdata = 0;
 275         devp->hd_flags |= HPET_OPEN;
 276         spin_unlock_irq(&hpet_lock);
 277         unlock_kernel();
 278
 279         hpet_timer_set_irq(devp);
 280
 281         return 0;
 282 }
 283
 284 static ssize_t
 285 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 286 {
 287         DECLARE_WAITQUEUE(wait, current);
 288         unsigned long data;
 289         ssize_t retval;
 290         struct hpet_dev *devp;
 291
 292         devp = file->private_data;
 293         if (!devp->hd_ireqfreq)
 294                 return -EIO;
 295
 296         if (count < sizeof(unsigned long))
 297                 return -EINVAL;
 298
 299         add_wait_queue(&devp->hd_waitqueue, &wait);
 300
 301         for ( ; ; ) {
 302                 set_current_state(TASK_INTERRUPTIBLE);
 303
 304                 spin_lock_irq(&hpet_lock);
 305                 data = devp->hd_irqdata;
 306                 devp->hd_irqdata = 0;
 307                 spin_unlock_irq(&hpet_lock);
 308
 309                 if (data)
 310                         break;
 311                 else if (file->f_flags & O_NONBLOCK) {
 312                         retval = -EAGAIN;
 313                         goto out;
 314                 } else if (signal_pending(current)) {
 315                         retval = -ERESTARTSYS;
 316                         goto out;
 317                 }
 318                 schedule();
 319         }
 320
 321         retval = put_user(data, (unsigned long __user *)buf);
 322         if (!retval)
 323                 retval = sizeof(unsigned long);
 324 out:
 325         __set_current_state(TASK_RUNNING);
 326         remove_wait_queue(&devp->hd_waitqueue, &wait);
 327
 328         return retval;
 329 }
 330
 331 static unsigned int hpet_poll(struct file *file, poll_table * wait)
 332 {
 333         unsigned long v;
 334         struct hpet_dev *devp;
 335
 336         devp = file->private_data;
 337
 338         if (!devp->hd_ireqfreq)
 339                 return 0;
 340
 341         poll_wait(file, &devp->hd_waitqueue, wait);
 342
 343         spin_lock_irq(&hpet_lock);
 344         v = devp->hd_irqdata;
 345         spin_unlock_irq(&hpet_lock);
 346
 347         if (v != 0)
 348                 return POLLIN | POLLRDNORM;
 349
 350         return 0;
 351 }
 352
 353 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 354 {
 355 #ifdef  CONFIG_HPET_MMAP
 356         struct hpet_dev *devp;
 357         unsigned long addr;
 358
 359         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
 360                 return -EINVAL;
 361
 362         devp = file->private_data;
 363         addr = devp->hd_hpets->hp_hpet_phys;
 364
 365         if (addr & (PAGE_SIZE - 1))
 366                 return -ENOSYS;
 367
 368         vma->vm_flags |= VM_IO;
 369         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 370
 371         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
 372                                         PAGE_SIZE, vma->vm_page_prot)) {
 373                 printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
 374                         __func__);
 375                 return -EAGAIN;
 376         }
 377
 378         return 0;
 379 #else
 380         return -ENOSYS;
 381 #endif
 382 }
 383
 384 static int hpet_fasync(int fd, struct file *file, int on)
 385 {
 386         struct hpet_dev *devp;
 387
 388         devp = file->private_data;
 389
 390         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 391                 return 0;
 392         else
 393                 return -EIO;
 394 }
 395
 396 static int hpet_release(struct inode *inode, struct file *file)
 397 {
 398         struct hpet_dev *devp;
 399         struct hpet_timer __iomem *timer;
 400         int irq = 0;
 401
 402         devp = file->private_data;
 403         timer = devp->hd_timer;
 404
 405         spin_lock_irq(&hpet_lock);
 406
 407         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 408                &timer->hpet_config);
 409
 410         irq = devp->hd_irq;
 411         devp->hd_irq = 0;
 412
 413         devp->hd_ireqfreq = 0;
 414
 415         if (devp->hd_flags & HPET_PERIODIC
 416             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 417                 unsigned long v;
 418
 419                 v = readq(&timer->hpet_config);
 420                 v ^= Tn_TYPE_CNF_MASK;
 421                 writeq(v, &timer->hpet_config);
 422         }
 423
 424         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 425         spin_unlock_irq(&hpet_lock);
 426
 427         if (irq)
 428                 free_irq(irq, devp);
 429
 430         if (file->f_flags & FASYNC)
 431                 hpet_fasync(-1, file, 0);
 432
 433         file->private_data = NULL;
 434         return 0;
 435 }
 436
 437 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
 438
 439 static int
 440 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 441            unsigned long arg)
 442 {
 443         struct hpet_dev *devp;
 444
 445         devp = file->private_data;
 446         return hpet_ioctl_common(devp, cmd, arg, 0);
 447 }
 448
 449 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 450 {
 451         struct hpet_timer __iomem *timer;
 452         struct hpet __iomem *hpet;
 453         struct hpets *hpetp;
 454         int irq;
 455         unsigned long g, v, t, m;
 456         unsigned long flags, isr;
 457
 458         timer = devp->hd_timer;
 459         hpet = devp->hd_hpet;
 460         hpetp = devp->hd_hpets;
 461
 462         if (!devp->hd_ireqfreq)
 463                 return -EIO;
 464
 465         spin_lock_irq(&hpet_lock);
 466
 467         if (devp->hd_flags & HPET_IE) {
 468                 spin_unlock_irq(&hpet_lock);
 469                 return -EBUSY;
 470         }
 471
 472         devp->hd_flags |= HPET_IE;
 473
 474         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 475                 devp->hd_flags |= HPET_SHARED_IRQ;
 476         spin_unlock_irq(&hpet_lock);
 477
 478         irq = devp->hd_hdwirq;
 479
 480         if (irq) {
 481                 unsigned long irq_flags;
 482
 483                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 484                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 485                                                 ? IRQF_SHARED : IRQF_DISABLED;
 486                 if (request_irq(irq, hpet_interrupt, irq_flags,
 487                                 devp->hd_name, (void *)devp)) {
 488                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 489                         irq = 0;
 490                 }
 491         }
 492
 493         if (irq == 0) {
 494                 spin_lock_irq(&hpet_lock);
 495                 devp->hd_flags ^= HPET_IE;
 496                 spin_unlock_irq(&hpet_lock);
 497                 return -EIO;
 498         }
 499
 500         devp->hd_irq = irq;
 501         t = devp->hd_ireqfreq;
 502         v = readq(&timer->hpet_config);
 503
 504         /* 64-bit comparators are not yet supported through the ioctls,
 505          * so force this into 32-bit mode if it supports both modes
 506          */
 507         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 508
 509         if (devp->hd_flags & HPET_PERIODIC) {
 510                 write_counter(t, &timer->hpet_compare);
 511                 g |= Tn_TYPE_CNF_MASK;
 512                 v |= Tn_TYPE_CNF_MASK;
 513                 writeq(v, &timer->hpet_config);
 514                 v |= Tn_VAL_SET_CNF_MASK;
 515                 writeq(v, &timer->hpet_config);
 516                 local_irq_save(flags);
 517
 518                 /* NOTE:  what we modify here is a hidden accumulator
 519                  * register supported by periodic-capable comparators.
 520                  * We never want to modify the (single) counter; that
 521                  * would affect all the comparators.
 522                  */
 523                 m = read_counter(&hpet->hpet_mc);
 524                 write_counter(t + m + hpetp->hp_delta, &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 int hpet_alloc(struct hpet_data *hdp)
 757 {
 758         u64 cap, mcfg;
 759         struct hpet_dev *devp;
 760         u32 i, ntimer;
 761         struct hpets *hpetp;
 762         size_t siz;
 763         struct hpet __iomem *hpet;
 764         static struct hpets *last = NULL;
 765         unsigned long period;
 766         unsigned long long temp;
 767         u32 remainder;
 768
 769         /*
 770          * hpet_alloc can be called by platform dependent code.
 771          * If platform dependent code has allocated the hpet that
 772          * ACPI has also reported, then we catch it here.
 773          */
 774         if (hpet_is_known(hdp)) {
 775                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 776                         __func__);
 777                 return 0;
 778         }
 779
 780         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 781                                       sizeof(struct hpet_dev));
 782
 783         hpetp = kzalloc(siz, GFP_KERNEL);
 784
 785         if (!hpetp)
 786                 return -ENOMEM;
 787
 788         hpetp->hp_which = hpet_nhpet++;
 789         hpetp->hp_hpet = hdp->hd_address;
 790         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 791
 792         hpetp->hp_ntimer = hdp->hd_nirqs;
 793
 794         for (i = 0; i < hdp->hd_nirqs; i++)
 795                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 796
 797         hpet = hpetp->hp_hpet;
 798
 799         cap = readq(&hpet->hpet_cap);
 800
 801         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 802
 803         if (hpetp->hp_ntimer != ntimer) {
 804                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 805                        " with number of timers\n");
 806                 kfree(hpetp);
 807                 return -ENODEV;
 808         }
 809
 810         if (last)
 811                 last->hp_next = hpetp;
 812         else
 813                 hpets = hpetp;
 814
 815         last = hpetp;
 816
 817         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 818                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 819         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 820         temp += period >> 1; /* round */
 821         do_div(temp, period);
 822         hpetp->hp_tick_freq = temp; /* ticks per second */
 823
 824         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 825                 hpetp->hp_which, hdp->hd_phys_address,
 826                 hpetp->hp_ntimer > 1 ? "s" : "");
 827         for (i = 0; i < hpetp->hp_ntimer; i++)
 828                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 829         printk("\n");
 830
 831         temp = hpetp->hp_tick_freq;
 832         remainder = do_div(temp, 1000000);
 833         printk(KERN_INFO
 834                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 835                 hpetp->hp_which, hpetp->hp_ntimer,
 836                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 837                 (unsigned) temp, remainder);
 838
 839         mcfg = readq(&hpet->hpet_config);
 840         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 841                 write_counter(0L, &hpet->hpet_mc);
 842                 mcfg |= HPET_ENABLE_CNF_MASK;
 843                 writeq(mcfg, &hpet->hpet_config);
 844         }
 845
 846         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 847                 struct hpet_timer __iomem *timer;
 848
 849                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 850
 851                 devp->hd_hpets = hpetp;
 852                 devp->hd_hpet = hpet;
 853                 devp->hd_timer = timer;
 854
 855                 /*
 856                  * If the timer was reserved by platform code,
 857                  * then make timer unavailable for opens.
 858                  */
 859                 if (hdp->hd_state & (1 << i)) {
 860                         devp->hd_flags = HPET_OPEN;
 861                         continue;
 862                 }
 863
 864                 init_waitqueue_head(&devp->hd_waitqueue);
 865         }
 866
 867         hpetp->hp_delta = hpet_calibrate(hpetp);
 868
 869 /* This clocksource driver currently only works on ia64 */
 870 #ifdef CONFIG_IA64
 871         if (!hpet_clocksource) {
 872                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 873                 CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
 874                 clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
 875                                                 clocksource_hpet.shift);
 876                 clocksource_register(&clocksource_hpet);
 877                 hpetp->hp_clocksource = &clocksource_hpet;
 878                 hpet_clocksource = &clocksource_hpet;
 879         }
 880 #endif
 881
 882         return 0;
 883 }
 884
 885 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 886 {
 887         struct hpet_data *hdp;
 888         acpi_status status;
 889         struct acpi_resource_address64 addr;
 890
 891         hdp = data;
 892
 893         status = acpi_resource_to_address64(res, &addr);
 894
 895         if (ACPI_SUCCESS(status)) {
 896                 hdp->hd_phys_address = addr.minimum;
 897                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 898
 899                 if (hpet_is_known(hdp)) {
 900                         iounmap(hdp->hd_address);
 901                         return AE_ALREADY_EXISTS;
 902                 }
 903         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 904                 struct acpi_resource_fixed_memory32 *fixmem32;
 905
 906                 fixmem32 = &res->data.fixed_memory32;
 907                 if (!fixmem32)
 908                         return AE_NO_MEMORY;
 909
 910                 hdp->hd_phys_address = fixmem32->address;
 911                 hdp->hd_address = ioremap(fixmem32->address,
 912                                                 HPET_RANGE_SIZE);
 913
 914                 if (hpet_is_known(hdp)) {
 915                         iounmap(hdp->hd_address);
 916                         return AE_ALREADY_EXISTS;
 917                 }
 918         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 919                 struct acpi_resource_extended_irq *irqp;
 920                 int i, irq;
 921
 922                 irqp = &res->data.extended_irq;
 923
 924                 for (i = 0; i < irqp->interrupt_count; i++) {
 925                         irq = acpi_register_gsi(irqp->interrupts[i],
 926                                       irqp->triggering, irqp->polarity);
 927                         if (irq < 0)
 928                                 return AE_ERROR;
 929
 930                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 931                         hdp->hd_nirqs++;
 932                 }
 933         }
 934
 935         return AE_OK;
 936 }
 937
 938 static int hpet_acpi_add(struct acpi_device *device)
 939 {
 940         acpi_status result;
 941         struct hpet_data data;
 942
 943         memset(&data, 0, sizeof(data));
 944
 945         result =
 946             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 947                                 hpet_resources, &data);
 948
 949         if (ACPI_FAILURE(result))
 950                 return -ENODEV;
 951
 952         if (!data.hd_address || !data.hd_nirqs) {
 953                 printk("%s: no address or irqs in _CRS\n", __func__);
 954                 return -ENODEV;
 955         }
 956
 957         return hpet_alloc(&data);
 958 }
 959
 960 static int hpet_acpi_remove(struct acpi_device *device, int type)
 961 {
 962         /* XXX need to unregister clocksource, dealloc mem, etc */
 963         return -EINVAL;
 964 }
 965
 966 static const struct acpi_device_id hpet_device_ids[] = {
 967         {"PNP0103", 0},
 968         {"", 0},
 969 };
 970 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
 971
 972 static struct acpi_driver hpet_acpi_driver = {
 973         .name = "hpet",
 974         .ids = hpet_device_ids,
 975         .ops = {
 976                 .add = hpet_acpi_add,
 977                 .remove = hpet_acpi_remove,
 978                 },
 979 };
 980
 981 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
 982
 983 static int __init hpet_init(void)
 984 {
 985         int result;
 986
 987         result = misc_register(&hpet_misc);
 988         if (result < 0)
 989                 return -ENODEV;
 990
 991         sysctl_header = register_sysctl_table(dev_root);
 992
 993         result = acpi_bus_register_driver(&hpet_acpi_driver);
 994         if (result < 0) {
 995                 if (sysctl_header)
 996                         unregister_sysctl_table(sysctl_header);
 997                 misc_deregister(&hpet_misc);
 998                 return result;
 999         }
1000
1001         return 0;
1002 }
1003
1004 static void __exit hpet_exit(void)
1005 {
1006         acpi_bus_unregister_driver(&hpet_acpi_driver);
1007
1008         if (sysctl_header)
1009                 unregister_sysctl_table(sysctl_header);
1010         misc_deregister(&hpet_misc);
1011
1012         return;
1013 }
1014
1015 module_init(hpet_init);
1016 module_exit(hpet_exit);
1017 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1018 MODULE_LICENSE("GPL");