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/config.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/module.h>
  17 #include <linux/kernel.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/proc_fs.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/wait.h>
  29 #include <linux/bcd.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/bitops.h>
  32
  33 #include <asm/current.h>
  34 #include <asm/uaccess.h>
  35 #include <asm/system.h>
  36 #include <asm/io.h>
  37 #include <asm/irq.h>
  38 #include <asm/div64.h>
  39
  40 #include <linux/acpi.h>
  41 #include <acpi/acpi_bus.h>
  42 #include <linux/hpet.h>
  43
  44 /*
  45  * The High Precision Event Timer driver.
  46  * This driver is closely modelled after the rtc.c driver.
  47  * http://www.intel.com/hardwaredesign/hpetspec.htm
  48  */
  49 #define HPET_USER_FREQ  (64)
  50 #define HPET_DRIFT      (500)
  51
  52 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
  53
  54 /* A lock for concurrent access by app and isr hpet activity. */
  55 static DEFINE_SPINLOCK(hpet_lock);
  56 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
  57 static DEFINE_SPINLOCK(hpet_task_lock);
  58
  59 #define HPET_DEV_NAME   (7)
  60
  61 struct hpet_dev {
  62         struct hpets *hd_hpets;
  63         struct hpet __iomem *hd_hpet;
  64         struct hpet_timer __iomem *hd_timer;
  65         unsigned long hd_ireqfreq;
  66         unsigned long hd_irqdata;
  67         wait_queue_head_t hd_waitqueue;
  68         struct fasync_struct *hd_async_queue;
  69         struct hpet_task *hd_task;
  70         unsigned int hd_flags;
  71         unsigned int hd_irq;
  72         unsigned int hd_hdwirq;
  73         char hd_name[HPET_DEV_NAME];
  74 };
  75
  76 struct hpets {
  77         struct hpets *hp_next;
  78         struct hpet __iomem *hp_hpet;
  79         unsigned long hp_hpet_phys;
  80         struct time_interpolator *hp_interpolator;
  81         unsigned long long hp_tick_freq;
  82         unsigned long hp_delta;
  83         unsigned int hp_ntimer;
  84         unsigned int hp_which;
  85         struct hpet_dev hp_dev[1];
  86 };
  87
  88 static struct hpets *hpets;
  89
  90 #define HPET_OPEN               0x0001
  91 #define HPET_IE                 0x0002  /* interrupt enabled */
  92 #define HPET_PERIODIC           0x0004
  93 #define HPET_SHARED_IRQ         0x0008
  94
  95 #if BITS_PER_LONG == 64
  96 #define write_counter(V, MC)    writeq(V, MC)
  97 #define read_counter(MC)        readq(MC)
  98 #else
  99 #define write_counter(V, MC)    writel(V, MC)
 100 #define read_counter(MC)        readl(MC)
 101 #endif
 102
 103 #ifndef readq
 104 static inline unsigned long long readq(void __iomem *addr)
 105 {
 106         return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
 107 }
 108 #endif
 109
 110 #ifndef writeq
 111 static inline void writeq(unsigned long long v, void __iomem *addr)
 112 {
 113         writel(v & 0xffffffff, addr);
 114         writel(v >> 32, addr + 4);
 115 }
 116 #endif
 117
 118 static irqreturn_t hpet_interrupt(int irq, void *data, struct pt_regs *regs)
 119 {
 120         struct hpet_dev *devp;
 121         unsigned long isr;
 122
 123         devp = data;
 124         isr = 1 << (devp - devp->hd_hpets->hp_dev);
 125
 126         if ((devp->hd_flags & HPET_SHARED_IRQ) &&
 127             !(isr & readl(&devp->hd_hpet->hpet_isr)))
 128                 return IRQ_NONE;
 129
 130         spin_lock(&hpet_lock);
 131         devp->hd_irqdata++;
 132
 133         /*
 134          * For non-periodic timers, increment the accumulator.
 135          * This has the effect of treating non-periodic like periodic.
 136          */
 137         if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
 138                 unsigned long m, t;
 139
 140                 t = devp->hd_ireqfreq;
 141                 m = read_counter(&devp->hd_hpet->hpet_mc);
 142                 write_counter(t + m + devp->hd_hpets->hp_delta,
 143                               &devp->hd_timer->hpet_compare);
 144         }
 145
 146         if (devp->hd_flags & HPET_SHARED_IRQ)
 147                 writel(isr, &devp->hd_hpet->hpet_isr);
 148         spin_unlock(&hpet_lock);
 149
 150         spin_lock(&hpet_task_lock);
 151         if (devp->hd_task)
 152                 devp->hd_task->ht_func(devp->hd_task->ht_data);
 153         spin_unlock(&hpet_task_lock);
 154
 155         wake_up_interruptible(&devp->hd_waitqueue);
 156
 157         kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
 158
 159         return IRQ_HANDLED;
 160 }
 161
 162 static int hpet_open(struct inode *inode, struct file *file)
 163 {
 164         struct hpet_dev *devp;
 165         struct hpets *hpetp;
 166         int i;
 167
 168         if (file->f_mode & FMODE_WRITE)
 169                 return -EINVAL;
 170
 171         spin_lock_irq(&hpet_lock);
 172
 173         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 174                 for (i = 0; i < hpetp->hp_ntimer; i++)
 175                         if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
 176                             || hpetp->hp_dev[i].hd_task)
 177                                 continue;
 178                         else {
 179                                 devp = &hpetp->hp_dev[i];
 180                                 break;
 181                         }
 182
 183         if (!devp) {
 184                 spin_unlock_irq(&hpet_lock);
 185                 return -EBUSY;
 186         }
 187
 188         file->private_data = devp;
 189         devp->hd_irqdata = 0;
 190         devp->hd_flags |= HPET_OPEN;
 191         spin_unlock_irq(&hpet_lock);
 192
 193         return 0;
 194 }
 195
 196 static ssize_t
 197 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 198 {
 199         DECLARE_WAITQUEUE(wait, current);
 200         unsigned long data;
 201         ssize_t retval;
 202         struct hpet_dev *devp;
 203
 204         devp = file->private_data;
 205         if (!devp->hd_ireqfreq)
 206                 return -EIO;
 207
 208         if (count < sizeof(unsigned long))
 209                 return -EINVAL;
 210
 211         add_wait_queue(&devp->hd_waitqueue, &wait);
 212
 213         for ( ; ; ) {
 214                 set_current_state(TASK_INTERRUPTIBLE);
 215
 216                 spin_lock_irq(&hpet_lock);
 217                 data = devp->hd_irqdata;
 218                 devp->hd_irqdata = 0;
 219                 spin_unlock_irq(&hpet_lock);
 220
 221                 if (data)
 222                         break;
 223                 else if (file->f_flags & O_NONBLOCK) {
 224                         retval = -EAGAIN;
 225                         goto out;
 226                 } else if (signal_pending(current)) {
 227                         retval = -ERESTARTSYS;
 228                         goto out;
 229                 }
 230                 schedule();
 231         }
 232
 233         retval = put_user(data, (unsigned long __user *)buf);
 234         if (!retval)
 235                 retval = sizeof(unsigned long);
 236 out:
 237         __set_current_state(TASK_RUNNING);
 238         remove_wait_queue(&devp->hd_waitqueue, &wait);
 239
 240         return retval;
 241 }
 242
 243 static unsigned int hpet_poll(struct file *file, poll_table * wait)
 244 {
 245         unsigned long v;
 246         struct hpet_dev *devp;
 247
 248         devp = file->private_data;
 249
 250         if (!devp->hd_ireqfreq)
 251                 return 0;
 252
 253         poll_wait(file, &devp->hd_waitqueue, wait);
 254
 255         spin_lock_irq(&hpet_lock);
 256         v = devp->hd_irqdata;
 257         spin_unlock_irq(&hpet_lock);
 258
 259         if (v != 0)
 260                 return POLLIN | POLLRDNORM;
 261
 262         return 0;
 263 }
 264
 265 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 266 {
 267 #ifdef  CONFIG_HPET_MMAP
 268         struct hpet_dev *devp;
 269         unsigned long addr;
 270
 271         if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
 272                 return -EINVAL;
 273
 274         devp = file->private_data;
 275         addr = devp->hd_hpets->hp_hpet_phys;
 276
 277         if (addr & (PAGE_SIZE - 1))
 278                 return -ENOSYS;
 279
 280         vma->vm_flags |= VM_IO;
 281         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 282
 283         if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
 284                                         PAGE_SIZE, vma->vm_page_prot)) {
 285                 printk(KERN_ERR "remap_pfn_range failed in hpet.c\n");
 286                 return -EAGAIN;
 287         }
 288
 289         return 0;
 290 #else
 291         return -ENOSYS;
 292 #endif
 293 }
 294
 295 static int hpet_fasync(int fd, struct file *file, int on)
 296 {
 297         struct hpet_dev *devp;
 298
 299         devp = file->private_data;
 300
 301         if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
 302                 return 0;
 303         else
 304                 return -EIO;
 305 }
 306
 307 static int hpet_release(struct inode *inode, struct file *file)
 308 {
 309         struct hpet_dev *devp;
 310         struct hpet_timer __iomem *timer;
 311         int irq = 0;
 312
 313         devp = file->private_data;
 314         timer = devp->hd_timer;
 315
 316         spin_lock_irq(&hpet_lock);
 317
 318         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 319                &timer->hpet_config);
 320
 321         irq = devp->hd_irq;
 322         devp->hd_irq = 0;
 323
 324         devp->hd_ireqfreq = 0;
 325
 326         if (devp->hd_flags & HPET_PERIODIC
 327             && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 328                 unsigned long v;
 329
 330                 v = readq(&timer->hpet_config);
 331                 v ^= Tn_TYPE_CNF_MASK;
 332                 writeq(v, &timer->hpet_config);
 333         }
 334
 335         devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
 336         spin_unlock_irq(&hpet_lock);
 337
 338         if (irq)
 339                 free_irq(irq, devp);
 340
 341         if (file->f_flags & FASYNC)
 342                 hpet_fasync(-1, file, 0);
 343
 344         file->private_data = NULL;
 345         return 0;
 346 }
 347
 348 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
 349
 350 static int
 351 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 352            unsigned long arg)
 353 {
 354         struct hpet_dev *devp;
 355
 356         devp = file->private_data;
 357         return hpet_ioctl_common(devp, cmd, arg, 0);
 358 }
 359
 360 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 361 {
 362         struct hpet_timer __iomem *timer;
 363         struct hpet __iomem *hpet;
 364         struct hpets *hpetp;
 365         int irq;
 366         unsigned long g, v, t, m;
 367         unsigned long flags, isr;
 368
 369         timer = devp->hd_timer;
 370         hpet = devp->hd_hpet;
 371         hpetp = devp->hd_hpets;
 372
 373         if (!devp->hd_ireqfreq)
 374                 return -EIO;
 375
 376         spin_lock_irq(&hpet_lock);
 377
 378         if (devp->hd_flags & HPET_IE) {
 379                 spin_unlock_irq(&hpet_lock);
 380                 return -EBUSY;
 381         }
 382
 383         devp->hd_flags |= HPET_IE;
 384
 385         if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
 386                 devp->hd_flags |= HPET_SHARED_IRQ;
 387         spin_unlock_irq(&hpet_lock);
 388
 389         irq = devp->hd_hdwirq;
 390
 391         if (irq) {
 392                 unsigned long irq_flags;
 393
 394                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
 395                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
 396                                                 ? SA_SHIRQ : SA_INTERRUPT;
 397                 if (request_irq(irq, hpet_interrupt, irq_flags,
 398                                 devp->hd_name, (void *)devp)) {
 399                         printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
 400                         irq = 0;
 401                 }
 402         }
 403
 404         if (irq == 0) {
 405                 spin_lock_irq(&hpet_lock);
 406                 devp->hd_flags ^= HPET_IE;
 407                 spin_unlock_irq(&hpet_lock);
 408                 return -EIO;
 409         }
 410
 411         devp->hd_irq = irq;
 412         t = devp->hd_ireqfreq;
 413         v = readq(&timer->hpet_config);
 414         g = v | Tn_INT_ENB_CNF_MASK;
 415
 416         if (devp->hd_flags & HPET_PERIODIC) {
 417                 write_counter(t, &timer->hpet_compare);
 418                 g |= Tn_TYPE_CNF_MASK;
 419                 v |= Tn_TYPE_CNF_MASK;
 420                 writeq(v, &timer->hpet_config);
 421                 v |= Tn_VAL_SET_CNF_MASK;
 422                 writeq(v, &timer->hpet_config);
 423                 local_irq_save(flags);
 424                 m = read_counter(&hpet->hpet_mc);
 425                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 426         } else {
 427                 local_irq_save(flags);
 428                 m = read_counter(&hpet->hpet_mc);
 429                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 430         }
 431
 432         if (devp->hd_flags & HPET_SHARED_IRQ) {
 433                 isr = 1 << (devp - hpets->hp_dev);
 434                 writel(isr, &hpet->hpet_isr);
 435         }
 436         writeq(g, &timer->hpet_config);
 437         local_irq_restore(flags);
 438
 439         return 0;
 440 }
 441
 442 /* converts Hz to number of timer ticks */
 443 static inline unsigned long hpet_time_div(struct hpets *hpets,
 444                                           unsigned long dis)
 445 {
 446         unsigned long long m;
 447
 448         m = hpets->hp_tick_freq + (dis >> 1);
 449         do_div(m, dis);
 450         return (unsigned long)m;
 451 }
 452
 453 static int
 454 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
 455 {
 456         struct hpet_timer __iomem *timer;
 457         struct hpet __iomem *hpet;
 458         struct hpets *hpetp;
 459         int err;
 460         unsigned long v;
 461
 462         switch (cmd) {
 463         case HPET_IE_OFF:
 464         case HPET_INFO:
 465         case HPET_EPI:
 466         case HPET_DPI:
 467         case HPET_IRQFREQ:
 468                 timer = devp->hd_timer;
 469                 hpet = devp->hd_hpet;
 470                 hpetp = devp->hd_hpets;
 471                 break;
 472         case HPET_IE_ON:
 473                 return hpet_ioctl_ieon(devp);
 474         default:
 475                 return -EINVAL;
 476         }
 477
 478         err = 0;
 479
 480         switch (cmd) {
 481         case HPET_IE_OFF:
 482                 if ((devp->hd_flags & HPET_IE) == 0)
 483                         break;
 484                 v = readq(&timer->hpet_config);
 485                 v &= ~Tn_INT_ENB_CNF_MASK;
 486                 writeq(v, &timer->hpet_config);
 487                 if (devp->hd_irq) {
 488                         free_irq(devp->hd_irq, devp);
 489                         devp->hd_irq = 0;
 490                 }
 491                 devp->hd_flags ^= HPET_IE;
 492                 break;
 493         case HPET_INFO:
 494                 {
 495                         struct hpet_info info;
 496
 497                         if (devp->hd_ireqfreq)
 498                                 info.hi_ireqfreq =
 499                                         hpet_time_div(hpetp, devp->hd_ireqfreq);
 500                         else
 501                                 info.hi_ireqfreq = 0;
 502                         info.hi_flags =
 503                             readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
 504                         info.hi_hpet = devp->hd_hpets->hp_which;
 505                         info.hi_timer = devp - devp->hd_hpets->hp_dev;
 506                         if (kernel)
 507                                 memcpy((void *)arg, &info, sizeof(info));
 508                         else
 509                                 if (copy_to_user((void __user *)arg, &info,
 510                                                  sizeof(info)))
 511                                         err = -EFAULT;
 512                         break;
 513                 }
 514         case HPET_EPI:
 515                 v = readq(&timer->hpet_config);
 516                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 517                         err = -ENXIO;
 518                         break;
 519                 }
 520                 devp->hd_flags |= HPET_PERIODIC;
 521                 break;
 522         case HPET_DPI:
 523                 v = readq(&timer->hpet_config);
 524                 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
 525                         err = -ENXIO;
 526                         break;
 527                 }
 528                 if (devp->hd_flags & HPET_PERIODIC &&
 529                     readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
 530                         v = readq(&timer->hpet_config);
 531                         v ^= Tn_TYPE_CNF_MASK;
 532                         writeq(v, &timer->hpet_config);
 533                 }
 534                 devp->hd_flags &= ~HPET_PERIODIC;
 535                 break;
 536         case HPET_IRQFREQ:
 537                 if (!kernel && (arg > hpet_max_freq) &&
 538                     !capable(CAP_SYS_RESOURCE)) {
 539                         err = -EACCES;
 540                         break;
 541                 }
 542
 543                 if (!arg) {
 544                         err = -EINVAL;
 545                         break;
 546                 }
 547
 548                 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
 549         }
 550
 551         return err;
 552 }
 553
 554 static struct file_operations hpet_fops = {
 555         .owner = THIS_MODULE,
 556         .llseek = no_llseek,
 557         .read = hpet_read,
 558         .poll = hpet_poll,
 559         .ioctl = hpet_ioctl,
 560         .open = hpet_open,
 561         .release = hpet_release,
 562         .fasync = hpet_fasync,
 563         .mmap = hpet_mmap,
 564 };
 565
 566 EXPORT_SYMBOL(hpet_alloc);
 567 EXPORT_SYMBOL(hpet_register);
 568 EXPORT_SYMBOL(hpet_unregister);
 569 EXPORT_SYMBOL(hpet_control);
 570
 571 int hpet_register(struct hpet_task *tp, int periodic)
 572 {
 573         unsigned int i;
 574         u64 mask;
 575         struct hpet_timer __iomem *timer;
 576         struct hpet_dev *devp;
 577         struct hpets *hpetp;
 578
 579         switch (periodic) {
 580         case 1:
 581                 mask = Tn_PER_INT_CAP_MASK;
 582                 break;
 583         case 0:
 584                 mask = 0;
 585                 break;
 586         default:
 587                 return -EINVAL;
 588         }
 589
 590         spin_lock_irq(&hpet_task_lock);
 591         spin_lock(&hpet_lock);
 592
 593         for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
 594                 for (timer = hpetp->hp_hpet->hpet_timers, i = 0;
 595                      i < hpetp->hp_ntimer; i++, timer++) {
 596                         if ((readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK)
 597                             != mask)
 598                                 continue;
 599
 600                         devp = &hpetp->hp_dev[i];
 601
 602                         if (devp->hd_flags & HPET_OPEN || devp->hd_task) {
 603                                 devp = NULL;
 604                                 continue;
 605                         }
 606
 607                         tp->ht_opaque = devp;
 608                         devp->hd_task = tp;
 609                         break;
 610                 }
 611
 612         spin_unlock(&hpet_lock);
 613         spin_unlock_irq(&hpet_task_lock);
 614
 615         if (tp->ht_opaque)
 616                 return 0;
 617         else
 618                 return -EBUSY;
 619 }
 620
 621 static inline int hpet_tpcheck(struct hpet_task *tp)
 622 {
 623         struct hpet_dev *devp;
 624         struct hpets *hpetp;
 625
 626         devp = tp->ht_opaque;
 627
 628         if (!devp)
 629                 return -ENXIO;
 630
 631         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 632                 if (devp >= hpetp->hp_dev
 633                     && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
 634                     && devp->hd_hpet == hpetp->hp_hpet)
 635                         return 0;
 636
 637         return -ENXIO;
 638 }
 639
 640 int hpet_unregister(struct hpet_task *tp)
 641 {
 642         struct hpet_dev *devp;
 643         struct hpet_timer __iomem *timer;
 644         int err;
 645
 646         if ((err = hpet_tpcheck(tp)))
 647                 return err;
 648
 649         spin_lock_irq(&hpet_task_lock);
 650         spin_lock(&hpet_lock);
 651
 652         devp = tp->ht_opaque;
 653         if (devp->hd_task != tp) {
 654                 spin_unlock(&hpet_lock);
 655                 spin_unlock_irq(&hpet_task_lock);
 656                 return -ENXIO;
 657         }
 658
 659         timer = devp->hd_timer;
 660         writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
 661                &timer->hpet_config);
 662         devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
 663         devp->hd_task = NULL;
 664         spin_unlock(&hpet_lock);
 665         spin_unlock_irq(&hpet_task_lock);
 666
 667         return 0;
 668 }
 669
 670 int hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
 671 {
 672         struct hpet_dev *devp;
 673         int err;
 674
 675         if ((err = hpet_tpcheck(tp)))
 676                 return err;
 677
 678         spin_lock_irq(&hpet_lock);
 679         devp = tp->ht_opaque;
 680         if (devp->hd_task != tp) {
 681                 spin_unlock_irq(&hpet_lock);
 682                 return -ENXIO;
 683         }
 684         spin_unlock_irq(&hpet_lock);
 685         return hpet_ioctl_common(devp, cmd, arg, 1);
 686 }
 687
 688 static ctl_table hpet_table[] = {
 689         {
 690          .ctl_name = 1,
 691          .procname = "max-user-freq",
 692          .data = &hpet_max_freq,
 693          .maxlen = sizeof(int),
 694          .mode = 0644,
 695          .proc_handler = &proc_dointvec,
 696          },
 697         {.ctl_name = 0}
 698 };
 699
 700 static ctl_table hpet_root[] = {
 701         {
 702          .ctl_name = 1,
 703          .procname = "hpet",
 704          .maxlen = 0,
 705          .mode = 0555,
 706          .child = hpet_table,
 707          },
 708         {.ctl_name = 0}
 709 };
 710
 711 static ctl_table dev_root[] = {
 712         {
 713          .ctl_name = CTL_DEV,
 714          .procname = "dev",
 715          .maxlen = 0,
 716          .mode = 0555,
 717          .child = hpet_root,
 718          },
 719         {.ctl_name = 0}
 720 };
 721
 722 static struct ctl_table_header *sysctl_header;
 723
 724 static void hpet_register_interpolator(struct hpets *hpetp)
 725 {
 726 #ifdef  CONFIG_TIME_INTERPOLATION
 727         struct time_interpolator *ti;
 728
 729         ti = kmalloc(sizeof(*ti), GFP_KERNEL);
 730         if (!ti)
 731                 return;
 732
 733         memset(ti, 0, sizeof(*ti));
 734         ti->source = TIME_SOURCE_MMIO64;
 735         ti->shift = 10;
 736         ti->addr = &hpetp->hp_hpet->hpet_mc;
 737         ti->frequency = hpetp->hp_tick_freq;
 738         ti->drift = HPET_DRIFT;
 739         ti->mask = -1;
 740
 741         hpetp->hp_interpolator = ti;
 742         register_time_interpolator(ti);
 743 #endif
 744 }
 745
 746 /*
 747  * Adjustment for when arming the timer with
 748  * initial conditions.  That is, main counter
 749  * ticks expired before interrupts are enabled.
 750  */
 751 #define TICK_CALIBRATE  (1000UL)
 752
 753 static unsigned long hpet_calibrate(struct hpets *hpetp)
 754 {
 755         struct hpet_timer __iomem *timer = NULL;
 756         unsigned long t, m, count, i, flags, start;
 757         struct hpet_dev *devp;
 758         int j;
 759         struct hpet __iomem *hpet;
 760
 761         for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
 762                 if ((devp->hd_flags & HPET_OPEN) == 0) {
 763                         timer = devp->hd_timer;
 764                         break;
 765                 }
 766
 767         if (!timer)
 768                 return 0;
 769
 770         hpet = hpets->hp_hpet;
 771         t = read_counter(&timer->hpet_compare);
 772
 773         i = 0;
 774         count = hpet_time_div(hpetp, TICK_CALIBRATE);
 775
 776         local_irq_save(flags);
 777
 778         start = read_counter(&hpet->hpet_mc);
 779
 780         do {
 781                 m = read_counter(&hpet->hpet_mc);
 782                 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
 783         } while (i++, (m - start) < count);
 784
 785         local_irq_restore(flags);
 786
 787         return (m - start) / i;
 788 }
 789
 790 int hpet_alloc(struct hpet_data *hdp)
 791 {
 792         u64 cap, mcfg;
 793         struct hpet_dev *devp;
 794         u32 i, ntimer;
 795         struct hpets *hpetp;
 796         size_t siz;
 797         struct hpet __iomem *hpet;
 798         static struct hpets *last = (struct hpets *)0;
 799         unsigned long ns, period;
 800         unsigned long long temp;
 801
 802         /*
 803          * hpet_alloc can be called by platform dependent code.
 804          * if platform dependent code has allocated the hpet
 805          * ACPI also reports hpet, then we catch it here.
 806          */
 807         for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 808                 if (hpetp->hp_hpet == hdp->hd_address)
 809                         return 0;
 810
 811         siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
 812                                       sizeof(struct hpet_dev));
 813
 814         hpetp = kmalloc(siz, GFP_KERNEL);
 815
 816         if (!hpetp)
 817                 return -ENOMEM;
 818
 819         memset(hpetp, 0, siz);
 820
 821         hpetp->hp_which = hpet_nhpet++;
 822         hpetp->hp_hpet = hdp->hd_address;
 823         hpetp->hp_hpet_phys = hdp->hd_phys_address;
 824
 825         hpetp->hp_ntimer = hdp->hd_nirqs;
 826
 827         for (i = 0; i < hdp->hd_nirqs; i++)
 828                 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
 829
 830         hpet = hpetp->hp_hpet;
 831
 832         cap = readq(&hpet->hpet_cap);
 833
 834         ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
 835
 836         if (hpetp->hp_ntimer != ntimer) {
 837                 printk(KERN_WARNING "hpet: number irqs doesn't agree"
 838                        " with number of timers\n");
 839                 kfree(hpetp);
 840                 return -ENODEV;
 841         }
 842
 843         if (last)
 844                 last->hp_next = hpetp;
 845         else
 846                 hpets = hpetp;
 847
 848         last = hpetp;
 849
 850         period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
 851                 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
 852         temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
 853         temp += period >> 1; /* round */
 854         do_div(temp, period);
 855         hpetp->hp_tick_freq = temp; /* ticks per second */
 856
 857         printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
 858                 hpetp->hp_which, hdp->hd_phys_address,
 859                 hpetp->hp_ntimer > 1 ? "s" : "");
 860         for (i = 0; i < hpetp->hp_ntimer; i++)
 861                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
 862         printk("\n");
 863
 864         ns = period / 1000000;  /* convert to nanoseconds, 10^-9 */
 865         printk(KERN_INFO "hpet%d: %ldns tick, %d %d-bit timers\n",
 866                 hpetp->hp_which, ns, hpetp->hp_ntimer,
 867                 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32);
 868
 869         mcfg = readq(&hpet->hpet_config);
 870         if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
 871                 write_counter(0L, &hpet->hpet_mc);
 872                 mcfg |= HPET_ENABLE_CNF_MASK;
 873                 writeq(mcfg, &hpet->hpet_config);
 874         }
 875
 876         for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
 877                 struct hpet_timer __iomem *timer;
 878
 879                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 880
 881                 devp->hd_hpets = hpetp;
 882                 devp->hd_hpet = hpet;
 883                 devp->hd_timer = timer;
 884
 885                 /*
 886                  * If the timer was reserved by platform code,
 887                  * then make timer unavailable for opens.
 888                  */
 889                 if (hdp->hd_state & (1 << i)) {
 890                         devp->hd_flags = HPET_OPEN;
 891                         continue;
 892                 }
 893
 894                 init_waitqueue_head(&devp->hd_waitqueue);
 895         }
 896
 897         hpetp->hp_delta = hpet_calibrate(hpetp);
 898         hpet_register_interpolator(hpetp);
 899
 900         return 0;
 901 }
 902
 903 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
 904 {
 905         struct hpet_data *hdp;
 906         acpi_status status;
 907         struct acpi_resource_address64 addr;
 908         struct hpets *hpetp;
 909
 910         hdp = data;
 911
 912         status = acpi_resource_to_address64(res, &addr);
 913
 914         if (ACPI_SUCCESS(status)) {
 915                 unsigned long size;
 916
 917                 size = addr.max_address_range - addr.min_address_range + 1;
 918                 hdp->hd_phys_address = addr.min_address_range;
 919                 hdp->hd_address = ioremap(addr.min_address_range, size);
 920
 921                 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
 922                         if (hpetp->hp_hpet == hdp->hd_address)
 923                                 return -EBUSY;
 924         } else if (res->id == ACPI_RSTYPE_EXT_IRQ) {
 925                 struct acpi_resource_ext_irq *irqp;
 926                 int i;
 927
 928                 irqp = &res->data.extended_irq;
 929
 930                 if (irqp->number_of_interrupts > 0) {
 931                         hdp->hd_nirqs = irqp->number_of_interrupts;
 932
 933                         for (i = 0; i < hdp->hd_nirqs; i++) {
 934                                 int rc =
 935                                     acpi_register_gsi(irqp->interrupts[i],
 936                                                       irqp->edge_level,
 937                                                       irqp->active_high_low);
 938                                 if (rc < 0)
 939                                         return AE_ERROR;
 940                                 hdp->hd_irq[i] = rc;
 941                         }
 942                 }
 943         }
 944
 945         return AE_OK;
 946 }
 947
 948 static int hpet_acpi_add(struct acpi_device *device)
 949 {
 950         acpi_status result;
 951         struct hpet_data data;
 952
 953         memset(&data, 0, sizeof(data));
 954
 955         result =
 956             acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 957                                 hpet_resources, &data);
 958
 959         if (ACPI_FAILURE(result))
 960                 return -ENODEV;
 961
 962         if (!data.hd_address || !data.hd_nirqs) {
 963                 printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
 964                 return -ENODEV;
 965         }
 966
 967         return hpet_alloc(&data);
 968 }
 969
 970 static int hpet_acpi_remove(struct acpi_device *device, int type)
 971 {
 972         /* XXX need to unregister interpolator, dealloc mem, etc */
 973         return -EINVAL;
 974 }
 975
 976 static struct acpi_driver hpet_acpi_driver = {
 977         .name = "hpet",
 978         .ids = "PNP0103",
 979         .ops = {
 980                 .add = hpet_acpi_add,
 981                 .remove = hpet_acpi_remove,
 982                 },
 983 };
 984
 985 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
 986
 987 static int __init hpet_init(void)
 988 {
 989         int result;
 990
 991         result = misc_register(&hpet_misc);
 992         if (result < 0)
 993                 return -ENODEV;
 994
 995         sysctl_header = register_sysctl_table(dev_root, 0);
 996
 997         result = acpi_bus_register_driver(&hpet_acpi_driver);
 998         if (result < 0) {
 999                 if (sysctl_header)
1000                         unregister_sysctl_table(sysctl_header);
1001                 misc_deregister(&hpet_misc);
1002                 return result;
1003         }
1004
1005         return 0;
1006 }
1007
1008 static void __exit hpet_exit(void)
1009 {
1010         acpi_bus_unregister_driver(&hpet_acpi_driver);
1011
1012         if (sysctl_header)
1013                 unregister_sysctl_table(sysctl_header);
1014         misc_deregister(&hpet_misc);
1015
1016         return;
1017 }
1018
1019 module_init(hpet_init);
1020 module_exit(hpet_exit);
1021 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1022 MODULE_LICENSE("GPL");