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         file->private_data = NULL;
 431         return 0;
 432 }
 433
 434 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
 435
 436 static int
 437 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 438            unsigned long arg)
 439 {
 440         struct hpet_dev *devp;
 441
 442         devp = file->private_data;
 443         return hpet_ioctl_common(devp, cmd, arg, 0);
 444 }
 445
 446 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 447 {
 448         struct hpet_timer __iomem *timer;
 449         struct hpet __iomem *hpet;
 450         struct hpets *hpetp;
 451         int irq;
 452         unsigned long g, v, t, m;
 453         unsigned long flags, isr;
 454
 455         timer = devp->hd_timer;
 456         hpet = devp->hd_hpet;
 457         hpetp = devp->hd_hpets;
 458
 459         if (!devp->hd_ireqfreq)
 460                 return -EIO;
 461
 462         spin_lock_irq(&hpet_lock);
 463
 464         if (devp->hd_flags & HPET_IE) {
 465                 spin_unlock_irq(&hpet_lock);
 466                 return -EBUSY;
 467         }
 468
 469         devp->hd_flags |= HPET_IE;
 470
 471         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 472                 devp->hd_flags |= HPET_SHARED_IRQ;
 473         spin_unlock_irq(&hpet_lock);
 474
 475         irq = devp->hd_hdwirq;
 476
 477         if (irq) {
 478                 unsigned long irq_flags;
 479
 480                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 481                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 482                                                 ? IRQF_SHARED : IRQF_DISABLED;
 483                 if (request_irq(irq, hpet_interrupt, irq_flags,
 484                                 devp->hd_name, (void *)devp)) {
 485                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 486                         irq = 0;
 487                 }
 488         }
 489
 490         if (irq == 0) {
 491                 spin_lock_irq(&hpet_lock);
 492                 devp->hd_flags ^= HPET_IE;
 493                 spin_unlock_irq(&hpet_lock);
 494                 return -EIO;
 495         }
 496
 497         devp->hd_irq = irq;
 498         t = devp->hd_ireqfreq;
 499         v = readq(&timer->hpet_config);
 500
 501         /* 64-bit comparators are not yet supported through the ioctls,
 502          * so force this into 32-bit mode if it supports both modes
 503          */
 504         g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
 505
 506         if (devp->hd_flags & HPET_PERIODIC) {
 507                 write_counter(t, &timer->hpet_compare);
 508                 g |= Tn_TYPE_CNF_MASK;
 509                 v |= Tn_TYPE_CNF_MASK;
 510                 writeq(v, &timer->hpet_config);
 511                 v |= Tn_VAL_SET_CNF_MASK;
 512                 writeq(v, &timer->hpet_config);
 513                 local_irq_save(flags);
 514
 515                 /* NOTE:  what we modify here is a hidden accumulator
 516                  * register supported by periodic-capable comparators.
 517                  * We never want to modify the (single) counter; that
 518                  * would affect all the comparators.
 519                  */
 520                 m = read_counter(&hpet->hpet_mc);
 521                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 522         } else {
 523                 local_irq_save(flags);
 524                 m = read_counter(&hpet->hpet_mc);
 525                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 526         }
 527
 528         if (devp->hd_flags & HPET_SHARED_IRQ) {
 529                 isr = 1 << (devp - devp->hd_hpets->hp_dev);
 530                 writel(isr, &hpet->hpet_isr);
 531         }
 532         writeq(g, &timer->hpet_config);
 533         local_irq_restore(flags);
 534
 535         return 0;
 536 }
 537
 538 /* converts Hz to number of timer ticks */
 539 static inline unsigned long hpet_time_div(struct hpets *hpets,
 540                                           unsigned long dis)
 541 {
 542         unsigned long long m;
 543
 544         m = hpets->hp_tick_freq + (dis >> 1);
 545         do_div(m, dis);
 546         return (unsigned long)m;
 547 }
 548
 549 static int
 550 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
 551 {
 552         struct hpet_timer __iomem *timer;
 553         struct hpet __iomem *hpet;
 554         struct hpets *hpetp;
 555         int err;
 556         unsigned long v;
 557
 558         switch (cmd) {
 559         case HPET_IE_OFF:
 560         case HPET_INFO:
 561         case HPET_EPI:
 562         case HPET_DPI:
 563         case HPET_IRQFREQ:
 564                 timer = devp->hd_timer;
 565                 hpet = devp->hd_hpet;
 566                 hpetp = devp->hd_hpets;
 567                 break;
 568         case HPET_IE_ON:
 569                 return hpet_ioctl_ieon(devp);
 570         default:
 571                 return -EINVAL;
 572         }
 573
 574         err = 0;
 575
 576         switch (cmd) {
 577         case HPET_IE_OFF:
 578                 if ((devp->hd_flags & HPET_IE) == 0)
 579                         break;
 580                 v = readq(&timer->hpet_config);
 581                 v &= ~Tn_INT_ENB_CNF_MASK;
 582                 writeq(v, &timer->hpet_config);
 583                 if (devp->hd_irq) {
 584                         free_irq(devp->hd_irq, devp);
 585                         devp->hd_irq = 0;
 586                 }
 587                 devp->hd_flags ^= HPET_IE;
 588                 break;
 589         case HPET_INFO:
 590                 {
 591                         struct hpet_info info;
 592
 593                         if (devp->hd_ireqfreq)
 594                                 info.hi_ireqfreq =
 595                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 596                         else
 597                                 info.hi_ireqfreq = 0;
 598                         info.hi_flags =
 599                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 600                         info.hi_hpet = hpetp->hp_which;
 601                         info.hi_timer = devp - hpetp->hp_dev;
 602                         if (kernel)
 603                                 memcpy((void *)arg, &info, sizeof(info));
 604                         else
 605                                 if (copy_to_user((void __user *)arg, &info,
 606                                                  sizeof(info)))
 607                                         err = -EFAULT;
 608                         break;
 609                 }
 610         case HPET_EPI:
 611                 v = readq(&timer->hpet_config);
 612                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 613                         err = -ENXIO;
 614                         break;
 615                 }
 616                 devp->hd_flags |= HPET_PERIODIC;
 617                 break;
 618         case HPET_DPI:
 619                 v = readq(&timer->hpet_config);
 620                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 621                         err = -ENXIO;
 622                         break;
 623                 }
 624                 if (devp->hd_flags & HPET_PERIODIC &&
 625                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 626                         v = readq(&timer->hpet_config);
 627                         v ^= Tn_TYPE_CNF_MASK;
 628                         writeq(v, &timer->hpet_config);
 629                 }
 630                 devp->hd_flags &= ~HPET_PERIODIC;
 631                 break;
 632         case HPET_IRQFREQ:
 633                 if (!kernel && (arg > hpet_max_freq) &&
 634                     !capable(CAP_SYS_RESOURCE)) {
 635                         err = -EACCES;
 636                         break;
 637                 }
 638
 639                 if (!arg) {
 640                         err = -EINVAL;
 641                         break;
 642                 }
 643
 644                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 645         }
 646
 647         return err;
 648 }
 649
 650 static const struct file_operations hpet_fops = {
 651         .owner = THIS_MODULE,
 652         .llseek = no_llseek,
 653         .read = hpet_read,
 654         .poll = hpet_poll,
 655         .ioctl = hpet_ioctl,
 656         .open = hpet_open,
 657         .release = hpet_release,
 658         .fasync = hpet_fasync,
 659         .mmap = hpet_mmap,
 660 };
 661
 662 static int hpet_is_known(struct hpet_data *hdp)
 663 {
 664         struct hpets *hpetp;
 665
 666         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 667                 if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
 668                         return 1;
 669
 670         return 0;
 671 }
 672
 673 static ctl_table hpet_table[] = {
 674         {
 675          .ctl_name = CTL_UNNUMBERED,
 676          .procname = "max-user-freq",
 677          .data = &hpet_max_freq,
 678          .maxlen = sizeof(int),
 679          .mode = 0644,
 680          .proc_handler = &proc_dointvec,
 681          },
 682         {.ctl_name = 0}
 683 };
 684
 685 static ctl_table hpet_root[] = {
 686         {
 687          .ctl_name = CTL_UNNUMBERED,
 688          .procname = "hpet",
 689          .maxlen = 0,
 690          .mode = 0555,
 691          .child = hpet_table,
 692          },
 693         {.ctl_name = 0}
 694 };
 695
 696 static ctl_table dev_root[] = {
 697         {
 698          .ctl_name = CTL_DEV,
 699          .procname = "dev",
 700          .maxlen = 0,
 701          .mode = 0555,
 702          .child = hpet_root,
 703          },
 704         {.ctl_name = 0}
 705 };
 706
 707 static struct ctl_table_header *sysctl_header;
 708
 709 /*
 710  * Adjustment for when arming the timer with
 711  * initial conditions.  That is, main counter
 712  * ticks expired before interrupts are enabled.
 713  */
 714 #define TICK_CALIBRATE  (1000UL)
 715
 716 static unsigned long hpet_calibrate(struct hpets *hpetp)
 717 {
 718         struct hpet_timer __iomem *timer = NULL;
 719         unsigned long t, m, count, i, flags, start;
 720         struct hpet_dev *devp;
 721         int j;
 722         struct hpet __iomem *hpet;
 723
 724         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 725                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 726                         timer = devp->hd_timer;
 727                         break;
 728                 }
 729
 730         if (!timer)
 731                 return 0;
 732
 733         hpet = hpetp->hp_hpet;
 734         t = read_counter(&timer->hpet_compare);
 735
 736         i = 0;
 737         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 738
 739         local_irq_save(flags);
 740
 741         start = read_counter(&hpet->hpet_mc);
 742
 743         do {
 744                 m = read_counter(&hpet->hpet_mc);
 745                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 746         } while (i++, (m - start) < count);
 747
 748         local_irq_restore(flags);
 749
 750         return (m - start) / i;
 751 }
 752
 753 int hpet_alloc(struct hpet_data *hdp)
 754 {
 755         u64 cap, mcfg;
 756         struct hpet_dev *devp;
 757         u32 i, ntimer;
 758         struct hpets *hpetp;
 759         size_t siz;
 760         struct hpet __iomem *hpet;
 761         static struct hpets *last = NULL;
 762         unsigned long period;
 763         unsigned long long temp;
 764         u32 remainder;
 765
 766         /*
 767          * hpet_alloc can be called by platform dependent code.
 768          * If platform dependent code has allocated the hpet that
 769          * ACPI has also reported, then we catch it here.
 770          */
 771         if (hpet_is_known(hdp)) {
 772                 printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
 773                         __func__);
 774                 return 0;
 775         }
 776
 777         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 778                                       sizeof(struct hpet_dev));
 779
 780         hpetp = kzalloc(siz, GFP_KERNEL);
 781
 782         if (!hpetp)
 783                 return -ENOMEM;
 784
 785         hpetp->hp_which = hpet_nhpet++;
 786         hpetp->hp_hpet = hdp->hd_address;
 787         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 788
 789         hpetp->hp_ntimer = hdp->hd_nirqs;
 790
 791         for (i = 0; i < hdp->hd_nirqs; i++)
 792                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 793
 794         hpet = hpetp->hp_hpet;
 795
 796         cap = readq(&hpet->hpet_cap);
 797
 798         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 799
 800         if (hpetp->hp_ntimer != ntimer) {
 801                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 802                        " with number of timers\n");
 803                 kfree(hpetp);
 804                 return -ENODEV;
 805         }
 806
 807         if (last)
 808                 last->hp_next = hpetp;
 809         else
 810                 hpets = hpetp;
 811
 812         last = hpetp;
 813
 814         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 815                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 816         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 817         temp += period >> 1; /* round */
 818         do_div(temp, period);
 819         hpetp->hp_tick_freq = temp; /* ticks per second */
 820
 821         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 822                 hpetp->hp_which, hdp->hd_phys_address,
 823                 hpetp->hp_ntimer > 1 ? "s" : "");
 824         for (i = 0; i < hpetp->hp_ntimer; i++)
 825                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 826         printk("\n");
 827
 828         temp = hpetp->hp_tick_freq;
 829         remainder = do_div(temp, 1000000);
 830         printk(KERN_INFO
 831                 "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
 832                 hpetp->hp_which, hpetp->hp_ntimer,
 833                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
 834                 (unsigned) temp, remainder);
 835
 836         mcfg = readq(&hpet->hpet_config);
 837         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 838                 write_counter(0L, &hpet->hpet_mc);
 839                 mcfg |= HPET_ENABLE_CNF_MASK;
 840                 writeq(mcfg, &hpet->hpet_config);
 841         }
 842
 843         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 844                 struct hpet_timer __iomem *timer;
 845
 846                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 847
 848                 devp->hd_hpets = hpetp;
 849                 devp->hd_hpet = hpet;
 850                 devp->hd_timer = timer;
 851
 852                 /*
 853                  * If the timer was reserved by platform code,
 854                  * then make timer unavailable for opens.
 855                  */
 856                 if (hdp->hd_state & (1 << i)) {
 857                         devp->hd_flags = HPET_OPEN;
 858                         continue;
 859                 }
 860
 861                 init_waitqueue_head(&devp->hd_waitqueue);
 862         }
 863
 864         hpetp->hp_delta = hpet_calibrate(hpetp);
 865
 866 /* This clocksource driver currently only works on ia64 */
 867 #ifdef CONFIG_IA64
 868         if (!hpet_clocksource) {
 869                 hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
 870                 CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
 871                 clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
 872                                                 clocksource_hpet.shift);
 873                 clocksource_register(&clocksource_hpet);
 874                 hpetp->hp_clocksource = &clocksource_hpet;
 875                 hpet_clocksource = &clocksource_hpet;
 876         }
 877 #endif
 878
 879         return 0;
 880 }
 881
 882 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 883 {
 884         struct hpet_data *hdp;
 885         acpi_status status;
 886         struct acpi_resource_address64 addr;
 887
 888         hdp = data;
 889
 890         status = acpi_resource_to_address64(res, &addr);
 891
 892         if (ACPI_SUCCESS(status)) {
 893                 hdp->hd_phys_address = addr.minimum;
 894                 hdp->hd_address = ioremap(addr.minimum, addr.address_length);
 895
 896                 if (hpet_is_known(hdp)) {
 897                         iounmap(hdp->hd_address);
 898                         return AE_ALREADY_EXISTS;
 899                 }
 900         } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
 901                 struct acpi_resource_fixed_memory32 *fixmem32;
 902
 903                 fixmem32 = &res->data.fixed_memory32;
 904                 if (!fixmem32)
 905                         return AE_NO_MEMORY;
 906
 907                 hdp->hd_phys_address = fixmem32->address;
 908                 hdp->hd_address = ioremap(fixmem32->address,
 909                                                 HPET_RANGE_SIZE);
 910
 911                 if (hpet_is_known(hdp)) {
 912                         iounmap(hdp->hd_address);
 913                         return AE_ALREADY_EXISTS;
 914                 }
 915         } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
 916                 struct acpi_resource_extended_irq *irqp;
 917                 int i, irq;
 918
 919                 irqp = &res->data.extended_irq;
 920
 921                 for (i = 0; i < irqp->interrupt_count; i++) {
 922                         irq = acpi_register_gsi(irqp->interrupts[i],
 923                                       irqp->triggering, irqp->polarity);
 924                         if (irq < 0)
 925                                 return AE_ERROR;
 926
 927                         hdp->hd_irq[hdp->hd_nirqs] = irq;
 928                         hdp->hd_nirqs++;
 929                 }
 930         }
 931
 932         return AE_OK;
 933 }
 934
 935 static int hpet_acpi_add(struct acpi_device *device)
 936 {
 937         acpi_status result;
 938         struct hpet_data data;
 939
 940         memset(&data, 0, sizeof(data));
 941
 942         result =
 943             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 944                                 hpet_resources, &data);
 945
 946         if (ACPI_FAILURE(result))
 947                 return -ENODEV;
 948
 949         if (!data.hd_address || !data.hd_nirqs) {
 950                 printk("%s: no address or irqs in _CRS\n", __func__);
 951                 return -ENODEV;
 952         }
 953
 954         return hpet_alloc(&data);
 955 }
 956
 957 static int hpet_acpi_remove(struct acpi_device *device, int type)
 958 {
 959         /* XXX need to unregister clocksource, dealloc mem, etc */
 960         return -EINVAL;
 961 }
 962
 963 static const struct acpi_device_id hpet_device_ids[] = {
 964         {"PNP0103", 0},
 965         {"", 0},
 966 };
 967 MODULE_DEVICE_TABLE(acpi, hpet_device_ids);
 968
 969 static struct acpi_driver hpet_acpi_driver = {
 970         .name = "hpet",
 971         .ids = hpet_device_ids,
 972         .ops = {
 973                 .add = hpet_acpi_add,
 974                 .remove = hpet_acpi_remove,
 975                 },
 976 };
 977
 978 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
 979
 980 static int __init hpet_init(void)
 981 {
 982         int result;
 983
 984         result = misc_register(&hpet_misc);
 985         if (result < 0)
 986                 return -ENODEV;
 987
 988         sysctl_header = register_sysctl_table(dev_root);
 989
 990         result = acpi_bus_register_driver(&hpet_acpi_driver);
 991         if (result < 0) {
 992                 if (sysctl_header)
 993                         unregister_sysctl_table(sysctl_header);
 994                 misc_deregister(&hpet_misc);
 995                 return result;
 996         }
 997
 998         return 0;
 999 }
1000
1001 static void __exit hpet_exit(void)
1002 {
1003         acpi_bus_unregister_driver(&hpet_acpi_driver);
1004
1005         if (sysctl_header)
1006                 unregister_sysctl_table(sysctl_header);
1007         misc_deregister(&hpet_misc);
1008
1009         return;
1010 }
1011
1012 module_init(hpet_init);
1013 module_exit(hpet_exit);
1014 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1015 MODULE_LICENSE("GPL");