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hpet.c

/*
 * Intel & MS High Precision Event Timer Implementation.
 *
 * Copyright (C) 2003 Intel Corporation
 *    Venki Pallipadi
 * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
 *    Bob Picco <robert.picco@hp.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/major.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/sysctl.h>
#include <linux/wait.h>
#include <linux/bcd.h>
#include <linux/seq_file.h>
#include <linux/bitops.h>
#include <linux/clocksource.h>

#include <asm/current.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/div64.h>

#include <linux/acpi.h>
#include <acpi/acpi_bus.h>
#include <linux/hpet.h>

/*
 * The High Precision Event Timer driver.
 * This driver is closely modelled after the rtc.c driver.
 * http://www.intel.com/hardwaredesign/hpetspec.htm
 */
#define     HPET_USER_FREQ    (64)
#define     HPET_DRIFT  (500)

#define HPET_RANGE_SIZE       1024  /* from HPET spec */

#if BITS_PER_LONG == 64
#define     write_counter(V, MC)    writeq(V, MC)
#define     read_counter(MC)  readq(MC)
#else
#define     write_counter(V, MC)    writel(V, MC)
#define     read_counter(MC)  readl(MC)
#endif

static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;

/* This clocksource driver currently only works on ia64 */
#ifdef CONFIG_IA64
static void __iomem *hpet_mctr;

static cycle_t read_hpet(void)
{
      return (cycle_t)read_counter((void __iomem *)hpet_mctr);
}

static struct clocksource clocksource_hpet = {
        .name           = "hpet",
        .rating         = 250,
        .read           = read_hpet,
        .mask           = CLOCKSOURCE_MASK(64),
        .mult           = 0, /*to be caluclated*/
        .shift          = 10,
        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
};
static struct clocksource *hpet_clocksource;
#endif

/* A lock for concurrent access by app and isr hpet activity. */
static DEFINE_SPINLOCK(hpet_lock);
/* A lock for concurrent intermodule access to hpet and isr hpet activity. */
static DEFINE_SPINLOCK(hpet_task_lock);

#define     HPET_DEV_NAME     (7)

struct hpet_dev {
      struct hpets *hd_hpets;
      struct hpet __iomem *hd_hpet;
      struct hpet_timer __iomem *hd_timer;
      unsigned long hd_ireqfreq;
      unsigned long hd_irqdata;
      wait_queue_head_t hd_waitqueue;
      struct fasync_struct *hd_async_queue;
      struct hpet_task *hd_task;
      unsigned int hd_flags;
      unsigned int hd_irq;
      unsigned int hd_hdwirq;
      char hd_name[HPET_DEV_NAME];
};

struct hpets {
      struct hpets *hp_next;
      struct hpet __iomem *hp_hpet;
      unsigned long hp_hpet_phys;
      struct clocksource *hp_clocksource;
      unsigned long long hp_tick_freq;
      unsigned long hp_delta;
      unsigned int hp_ntimer;
      unsigned int hp_which;
      struct hpet_dev hp_dev[1];
};

static struct hpets *hpets;

#define     HPET_OPEN         0x0001
#define     HPET_IE                 0x0002      /* interrupt enabled */
#define     HPET_PERIODIC           0x0004
#define     HPET_SHARED_IRQ         0x0008


#ifndef readq
static inline unsigned long long readq(void __iomem *addr)
{
      return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
}
#endif

#ifndef writeq
static inline void writeq(unsigned long long v, void __iomem *addr)
{
      writel(v & 0xffffffff, addr);
      writel(v >> 32, addr + 4);
}
#endif

static irqreturn_t hpet_interrupt(int irq, void *data)
{
      struct hpet_dev *devp;
      unsigned long isr;

      devp = data;
      isr = 1 << (devp - devp->hd_hpets->hp_dev);

      if ((devp->hd_flags & HPET_SHARED_IRQ) &&
          !(isr & readl(&devp->hd_hpet->hpet_isr)))
            return IRQ_NONE;

      spin_lock(&hpet_lock);
      devp->hd_irqdata++;

      /*
       * For non-periodic timers, increment the accumulator.
       * This has the effect of treating non-periodic like periodic.
       */
      if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
            unsigned long m, t;

            t = devp->hd_ireqfreq;
            m = read_counter(&devp->hd_hpet->hpet_mc);
            write_counter(t + m + devp->hd_hpets->hp_delta,
                        &devp->hd_timer->hpet_compare);
      }

      if (devp->hd_flags & HPET_SHARED_IRQ)
            writel(isr, &devp->hd_hpet->hpet_isr);
      spin_unlock(&hpet_lock);

      spin_lock(&hpet_task_lock);
      if (devp->hd_task)
            devp->hd_task->ht_func(devp->hd_task->ht_data);
      spin_unlock(&hpet_task_lock);

      wake_up_interruptible(&devp->hd_waitqueue);

      kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);

      return IRQ_HANDLED;
}

static int hpet_open(struct inode *inode, struct file *file)
{
      struct hpet_dev *devp;
      struct hpets *hpetp;
      int i;

      if (file->f_mode & FMODE_WRITE)
            return -EINVAL;

      spin_lock_irq(&hpet_lock);

      for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
            for (i = 0; i < hpetp->hp_ntimer; i++)
                  if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
                      || hpetp->hp_dev[i].hd_task)
                        continue;
                  else {
                        devp = &hpetp->hp_dev[i];
                        break;
                  }

      if (!devp) {
            spin_unlock_irq(&hpet_lock);
            return -EBUSY;
      }

      file->private_data = devp;
      devp->hd_irqdata = 0;
      devp->hd_flags |= HPET_OPEN;
      spin_unlock_irq(&hpet_lock);

      return 0;
}

static ssize_t
hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
{
      DECLARE_WAITQUEUE(wait, current);
      unsigned long data;
      ssize_t retval;
      struct hpet_dev *devp;

      devp = file->private_data;
      if (!devp->hd_ireqfreq)
            return -EIO;

      if (count < sizeof(unsigned long))
            return -EINVAL;

      add_wait_queue(&devp->hd_waitqueue, &wait);

      for ( ; ; ) {
            set_current_state(TASK_INTERRUPTIBLE);

            spin_lock_irq(&hpet_lock);
            data = devp->hd_irqdata;
            devp->hd_irqdata = 0;
            spin_unlock_irq(&hpet_lock);

            if (data)
                  break;
            else if (file->f_flags & O_NONBLOCK) {
                  retval = -EAGAIN;
                  goto out;
            } else if (signal_pending(current)) {
                  retval = -ERESTARTSYS;
                  goto out;
            }
            schedule();
      }

      retval = put_user(data, (unsigned long __user *)buf);
      if (!retval)
            retval = sizeof(unsigned long);
out:
      __set_current_state(TASK_RUNNING);
      remove_wait_queue(&devp->hd_waitqueue, &wait);

      return retval;
}

static unsigned int hpet_poll(struct file *file, poll_table * wait)
{
      unsigned long v;
      struct hpet_dev *devp;

      devp = file->private_data;

      if (!devp->hd_ireqfreq)
            return 0;

      poll_wait(file, &devp->hd_waitqueue, wait);

      spin_lock_irq(&hpet_lock);
      v = devp->hd_irqdata;
      spin_unlock_irq(&hpet_lock);

      if (v != 0)
            return POLLIN | POLLRDNORM;

      return 0;
}

static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
{
#ifdef      CONFIG_HPET_MMAP
      struct hpet_dev *devp;
      unsigned long addr;

      if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
            return -EINVAL;

      devp = file->private_data;
      addr = devp->hd_hpets->hp_hpet_phys;

      if (addr & (PAGE_SIZE - 1))
            return -ENOSYS;

      vma->vm_flags |= VM_IO;
      vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

      if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
                              PAGE_SIZE, vma->vm_page_prot)) {
            printk(KERN_ERR "%s: io_remap_pfn_range failed\n",
                  __FUNCTION__);
            return -EAGAIN;
      }

      return 0;
#else
      return -ENOSYS;
#endif
}

static int hpet_fasync(int fd, struct file *file, int on)
{
      struct hpet_dev *devp;

      devp = file->private_data;

      if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
            return 0;
      else
            return -EIO;
}

static int hpet_release(struct inode *inode, struct file *file)
{
      struct hpet_dev *devp;
      struct hpet_timer __iomem *timer;
      int irq = 0;

      devp = file->private_data;
      timer = devp->hd_timer;

      spin_lock_irq(&hpet_lock);

      writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
             &timer->hpet_config);

      irq = devp->hd_irq;
      devp->hd_irq = 0;

      devp->hd_ireqfreq = 0;

      if (devp->hd_flags & HPET_PERIODIC
          && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
            unsigned long v;

            v = readq(&timer->hpet_config);
            v ^= Tn_TYPE_CNF_MASK;
            writeq(v, &timer->hpet_config);
      }

      devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
      spin_unlock_irq(&hpet_lock);

      if (irq)
            free_irq(irq, devp);

      if (file->f_flags & FASYNC)
            hpet_fasync(-1, file, 0);

      file->private_data = NULL;
      return 0;
}

static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);

static int
hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
         unsigned long arg)
{
      struct hpet_dev *devp;

      devp = file->private_data;
      return hpet_ioctl_common(devp, cmd, arg, 0);
}

static int hpet_ioctl_ieon(struct hpet_dev *devp)
{
      struct hpet_timer __iomem *timer;
      struct hpet __iomem *hpet;
      struct hpets *hpetp;
      int irq;
      unsigned long g, v, t, m;
      unsigned long flags, isr;

      timer = devp->hd_timer;
      hpet = devp->hd_hpet;
      hpetp = devp->hd_hpets;

      if (!devp->hd_ireqfreq)
            return -EIO;

      spin_lock_irq(&hpet_lock);

      if (devp->hd_flags & HPET_IE) {
            spin_unlock_irq(&hpet_lock);
            return -EBUSY;
      }

      devp->hd_flags |= HPET_IE;

      if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
            devp->hd_flags |= HPET_SHARED_IRQ;
      spin_unlock_irq(&hpet_lock);

      irq = devp->hd_hdwirq;

      if (irq) {
            unsigned long irq_flags;

            sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
            irq_flags = devp->hd_flags & HPET_SHARED_IRQ
                                    ? IRQF_SHARED : IRQF_DISABLED;
            if (request_irq(irq, hpet_interrupt, irq_flags,
                        devp->hd_name, (void *)devp)) {
                  printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
                  irq = 0;
            }
      }

      if (irq == 0) {
            spin_lock_irq(&hpet_lock);
            devp->hd_flags ^= HPET_IE;
            spin_unlock_irq(&hpet_lock);
            return -EIO;
      }

      devp->hd_irq = irq;
      t = devp->hd_ireqfreq;
      v = readq(&timer->hpet_config);
      g = v | Tn_INT_ENB_CNF_MASK;

      if (devp->hd_flags & HPET_PERIODIC) {
            write_counter(t, &timer->hpet_compare);
            g |= Tn_TYPE_CNF_MASK;
            v |= Tn_TYPE_CNF_MASK;
            writeq(v, &timer->hpet_config);
            v |= Tn_VAL_SET_CNF_MASK;
            writeq(v, &timer->hpet_config);
            local_irq_save(flags);
            m = read_counter(&hpet->hpet_mc);
            write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
      } else {
            local_irq_save(flags);
            m = read_counter(&hpet->hpet_mc);
            write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
      }

      if (devp->hd_flags & HPET_SHARED_IRQ) {
            isr = 1 << (devp - devp->hd_hpets->hp_dev);
            writel(isr, &hpet->hpet_isr);
      }
      writeq(g, &timer->hpet_config);
      local_irq_restore(flags);

      return 0;
}

/* converts Hz to number of timer ticks */
static inline unsigned long hpet_time_div(struct hpets *hpets,
                                unsigned long dis)
{
      unsigned long long m;

      m = hpets->hp_tick_freq + (dis >> 1);
      do_div(m, dis);
      return (unsigned long)m;
}

static int
hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
{
      struct hpet_timer __iomem *timer;
      struct hpet __iomem *hpet;
      struct hpets *hpetp;
      int err;
      unsigned long v;

      switch (cmd) {
      case HPET_IE_OFF:
      case HPET_INFO:
      case HPET_EPI:
      case HPET_DPI:
      case HPET_IRQFREQ:
            timer = devp->hd_timer;
            hpet = devp->hd_hpet;
            hpetp = devp->hd_hpets;
            break;
      case HPET_IE_ON:
            return hpet_ioctl_ieon(devp);
      default:
            return -EINVAL;
      }

      err = 0;

      switch (cmd) {
      case HPET_IE_OFF:
            if ((devp->hd_flags & HPET_IE) == 0)
                  break;
            v = readq(&timer->hpet_config);
            v &= ~Tn_INT_ENB_CNF_MASK;
            writeq(v, &timer->hpet_config);
            if (devp->hd_irq) {
                  free_irq(devp->hd_irq, devp);
                  devp->hd_irq = 0;
            }
            devp->hd_flags ^= HPET_IE;
            break;
      case HPET_INFO:
            {
                  struct hpet_info info;

                  if (devp->hd_ireqfreq)
                        info.hi_ireqfreq =
                              hpet_time_div(hpetp, devp->hd_ireqfreq);
                  else
                        info.hi_ireqfreq = 0;
                  info.hi_flags =
                      readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
                  info.hi_hpet = hpetp->hp_which;
                  info.hi_timer = devp - hpetp->hp_dev;
                  if (kernel)
                        memcpy((void *)arg, &info, sizeof(info));
                  else
                        if (copy_to_user((void __user *)arg, &info,
                                     sizeof(info)))
                              err = -EFAULT;
                  break;
            }
      case HPET_EPI:
            v = readq(&timer->hpet_config);
            if ((v & Tn_PER_INT_CAP_MASK) == 0) {
                  err = -ENXIO;
                  break;
            }
            devp->hd_flags |= HPET_PERIODIC;
            break;
      case HPET_DPI:
            v = readq(&timer->hpet_config);
            if ((v & Tn_PER_INT_CAP_MASK) == 0) {
                  err = -ENXIO;
                  break;
            }
            if (devp->hd_flags & HPET_PERIODIC &&
                readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
                  v = readq(&timer->hpet_config);
                  v ^= Tn_TYPE_CNF_MASK;
                  writeq(v, &timer->hpet_config);
            }
            devp->hd_flags &= ~HPET_PERIODIC;
            break;
      case HPET_IRQFREQ:
            if (!kernel && (arg > hpet_max_freq) &&
                !capable(CAP_SYS_RESOURCE)) {
                  err = -EACCES;
                  break;
            }

            if (!arg) {
                  err = -EINVAL;
                  break;
            }

            devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
      }

      return err;
}

static const struct file_operations hpet_fops = {
      .owner = THIS_MODULE,
      .llseek = no_llseek,
      .read = hpet_read,
      .poll = hpet_poll,
      .ioctl = hpet_ioctl,
      .open = hpet_open,
      .release = hpet_release,
      .fasync = hpet_fasync,
      .mmap = hpet_mmap,
};

static int hpet_is_known(struct hpet_data *hdp)
{
      struct hpets *hpetp;

      for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
            if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
                  return 1;

      return 0;
}

EXPORT_SYMBOL(hpet_alloc);
EXPORT_SYMBOL(hpet_register);
EXPORT_SYMBOL(hpet_unregister);
EXPORT_SYMBOL(hpet_control);

int hpet_register(struct hpet_task *tp, int periodic)
{
      unsigned int i;
      u64 mask;
      struct hpet_timer __iomem *timer;
      struct hpet_dev *devp;
      struct hpets *hpetp;

      switch (periodic) {
      case 1:
            mask = Tn_PER_INT_CAP_MASK;
            break;
      case 0:
            mask = 0;
            break;
      default:
            return -EINVAL;
      }

      tp->ht_opaque = NULL;

      spin_lock_irq(&hpet_task_lock);
      spin_lock(&hpet_lock);

      for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
            for (timer = hpetp->hp_hpet->hpet_timers, i = 0;
                 i < hpetp->hp_ntimer; i++, timer++) {
                  if ((readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK)
                      != mask)
                        continue;

                  devp = &hpetp->hp_dev[i];

                  if (devp->hd_flags & HPET_OPEN || devp->hd_task) {
                        devp = NULL;
                        continue;
                  }

                  tp->ht_opaque = devp;
                  devp->hd_task = tp;
                  break;
            }

      spin_unlock(&hpet_lock);
      spin_unlock_irq(&hpet_task_lock);

      if (tp->ht_opaque)
            return 0;
      else
            return -EBUSY;
}

static inline int hpet_tpcheck(struct hpet_task *tp)
{
      struct hpet_dev *devp;
      struct hpets *hpetp;

      devp = tp->ht_opaque;

      if (!devp)
            return -ENXIO;

      for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
            if (devp >= hpetp->hp_dev
                && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
                && devp->hd_hpet == hpetp->hp_hpet)
                  return 0;

      return -ENXIO;
}

int hpet_unregister(struct hpet_task *tp)
{
      struct hpet_dev *devp;
      struct hpet_timer __iomem *timer;
      int err;

      if ((err = hpet_tpcheck(tp)))
            return err;

      spin_lock_irq(&hpet_task_lock);
      spin_lock(&hpet_lock);

      devp = tp->ht_opaque;
      if (devp->hd_task != tp) {
            spin_unlock(&hpet_lock);
            spin_unlock_irq(&hpet_task_lock);
            return -ENXIO;
      }

      timer = devp->hd_timer;
      writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
             &timer->hpet_config);
      devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
      devp->hd_task = NULL;
      spin_unlock(&hpet_lock);
      spin_unlock_irq(&hpet_task_lock);

      return 0;
}

int hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
{
      struct hpet_dev *devp;
      int err;

      if ((err = hpet_tpcheck(tp)))
            return err;

      spin_lock_irq(&hpet_lock);
      devp = tp->ht_opaque;
      if (devp->hd_task != tp) {
            spin_unlock_irq(&hpet_lock);
            return -ENXIO;
      }
      spin_unlock_irq(&hpet_lock);
      return hpet_ioctl_common(devp, cmd, arg, 1);
}

static ctl_table hpet_table[] = {
      {
       .ctl_name = CTL_UNNUMBERED,
       .procname = "max-user-freq",
       .data = &hpet_max_freq,
       .maxlen = sizeof(int),
       .mode = 0644,
       .proc_handler = &proc_dointvec,
       },
      {.ctl_name = 0}
};

static ctl_table hpet_root[] = {
      {
       .ctl_name = CTL_UNNUMBERED,
       .procname = "hpet",
       .maxlen = 0,
       .mode = 0555,
       .child = hpet_table,
       },
      {.ctl_name = 0}
};

static ctl_table dev_root[] = {
      {
       .ctl_name = CTL_DEV,
       .procname = "dev",
       .maxlen = 0,
       .mode = 0555,
       .child = hpet_root,
       },
      {.ctl_name = 0}
};

static struct ctl_table_header *sysctl_header;

/*
 * Adjustment for when arming the timer with
 * initial conditions.  That is, main counter
 * ticks expired before interrupts are enabled.
 */
#define     TICK_CALIBRATE    (1000UL)

static unsigned long hpet_calibrate(struct hpets *hpetp)
{
      struct hpet_timer __iomem *timer = NULL;
      unsigned long t, m, count, i, flags, start;
      struct hpet_dev *devp;
      int j;
      struct hpet __iomem *hpet;

      for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
            if ((devp->hd_flags & HPET_OPEN) == 0) {
                  timer = devp->hd_timer;
                  break;
            }

      if (!timer)
            return 0;

      hpet = hpetp->hp_hpet;
      t = read_counter(&timer->hpet_compare);

      i = 0;
      count = hpet_time_div(hpetp, TICK_CALIBRATE);

      local_irq_save(flags);

      start = read_counter(&hpet->hpet_mc);

      do {
            m = read_counter(&hpet->hpet_mc);
            write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
      } while (i++, (m - start) < count);

      local_irq_restore(flags);

      return (m - start) / i;
}

int hpet_alloc(struct hpet_data *hdp)
{
      u64 cap, mcfg;
      struct hpet_dev *devp;
      u32 i, ntimer;
      struct hpets *hpetp;
      size_t siz;
      struct hpet __iomem *hpet;
      static struct hpets *last = NULL;
      unsigned long period;
      unsigned long long temp;

      /*
       * hpet_alloc can be called by platform dependent code.
       * If platform dependent code has allocated the hpet that
       * ACPI has also reported, then we catch it here.
       */
      if (hpet_is_known(hdp)) {
            printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
                  __FUNCTION__);
            return 0;
      }

      siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
                              sizeof(struct hpet_dev));

      hpetp = kzalloc(siz, GFP_KERNEL);

      if (!hpetp)
            return -ENOMEM;

      hpetp->hp_which = hpet_nhpet++;
      hpetp->hp_hpet = hdp->hd_address;
      hpetp->hp_hpet_phys = hdp->hd_phys_address;

      hpetp->hp_ntimer = hdp->hd_nirqs;

      for (i = 0; i < hdp->hd_nirqs; i++)
            hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];

      hpet = hpetp->hp_hpet;

      cap = readq(&hpet->hpet_cap);

      ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;

      if (hpetp->hp_ntimer != ntimer) {
            printk(KERN_WARNING "hpet: number irqs doesn't agree"
                   " with number of timers\n");
            kfree(hpetp);
            return -ENODEV;
      }

      if (last)
            last->hp_next = hpetp;
      else
            hpets = hpetp;

      last = hpetp;

      period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
            HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
      temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
      temp += period >> 1; /* round */
      do_div(temp, period);
      hpetp->hp_tick_freq = temp; /* ticks per second */

      printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
            hpetp->hp_which, hdp->hd_phys_address,
            hpetp->hp_ntimer > 1 ? "s" : "");
      for (i = 0; i < hpetp->hp_ntimer; i++)
            printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
      printk("\n");

      printk(KERN_INFO "hpet%u: %u %d-bit timers, %Lu Hz\n",
             hpetp->hp_which, hpetp->hp_ntimer,
             cap & HPET_COUNTER_SIZE_MASK ? 64 : 32, hpetp->hp_tick_freq);

      mcfg = readq(&hpet->hpet_config);
      if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
            write_counter(0L, &hpet->hpet_mc);
            mcfg |= HPET_ENABLE_CNF_MASK;
            writeq(mcfg, &hpet->hpet_config);
      }

      for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
            struct hpet_timer __iomem *timer;

            timer = &hpet->hpet_timers[devp - hpetp->hp_dev];

            devp->hd_hpets = hpetp;
            devp->hd_hpet = hpet;
            devp->hd_timer = timer;

            /*
             * If the timer was reserved by platform code,
             * then make timer unavailable for opens.
             */
            if (hdp->hd_state & (1 << i)) {
                  devp->hd_flags = HPET_OPEN;
                  continue;
            }

            init_waitqueue_head(&devp->hd_waitqueue);
      }

      hpetp->hp_delta = hpet_calibrate(hpetp);

/* This clocksource driver currently only works on ia64 */
#ifdef CONFIG_IA64
      if (!hpet_clocksource) {
            hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
            CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
            clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
                                    clocksource_hpet.shift);
            clocksource_register(&clocksource_hpet);
            hpetp->hp_clocksource = &clocksource_hpet;
            hpet_clocksource = &clocksource_hpet;
      }
#endif

      return 0;
}

static acpi_status hpet_resources(struct acpi_resource *res, void *data)
{
      struct hpet_data *hdp;
      acpi_status status;
      struct acpi_resource_address64 addr;

      hdp = data;

      status = acpi_resource_to_address64(res, &addr);

      if (ACPI_SUCCESS(status)) {
            hdp->hd_phys_address = addr.minimum;
            hdp->hd_address = ioremap(addr.minimum, addr.address_length);

            if (hpet_is_known(hdp)) {
                  printk(KERN_DEBUG "%s: 0x%lx is busy\n",
                        __FUNCTION__, hdp->hd_phys_address);
                  iounmap(hdp->hd_address);
                  return AE_ALREADY_EXISTS;
            }
      } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
            struct acpi_resource_fixed_memory32 *fixmem32;

            fixmem32 = &res->data.fixed_memory32;
            if (!fixmem32)
                  return AE_NO_MEMORY;

            hdp->hd_phys_address = fixmem32->address;
            hdp->hd_address = ioremap(fixmem32->address,
                                    HPET_RANGE_SIZE);

            if (hpet_is_known(hdp)) {
                  printk(KERN_DEBUG "%s: 0x%lx is busy\n",
                        __FUNCTION__, hdp->hd_phys_address);
                  iounmap(hdp->hd_address);
                  return AE_ALREADY_EXISTS;
            }
      } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
            struct acpi_resource_extended_irq *irqp;
            int i, irq;

            irqp = &res->data.extended_irq;

            for (i = 0; i < irqp->interrupt_count; i++) {
                  irq = acpi_register_gsi(irqp->interrupts[i],
                              irqp->triggering, irqp->polarity);
                  if (irq < 0)
                        return AE_ERROR;

                  hdp->hd_irq[hdp->hd_nirqs] = irq;
                  hdp->hd_nirqs++;
            }
      }

      return AE_OK;
}

static int hpet_acpi_add(struct acpi_device *device)
{
      acpi_status result;
      struct hpet_data data;

      memset(&data, 0, sizeof(data));

      result =
          acpi_walk_resources(device->handle, METHOD_NAME__CRS,
                        hpet_resources, &data);

      if (ACPI_FAILURE(result))
            return -ENODEV;

      if (!data.hd_address || !data.hd_nirqs) {
            printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
            return -ENODEV;
      }

      return hpet_alloc(&data);
}

static int hpet_acpi_remove(struct acpi_device *device, int type)
{
      /* XXX need to unregister clocksource, dealloc mem, etc */
      return -EINVAL;
}

static const struct acpi_device_id hpet_device_ids[] = {
      {"PNP0103", 0},
      {"", 0},
};
MODULE_DEVICE_TABLE(acpi, hpet_device_ids);

static struct acpi_driver hpet_acpi_driver = {
      .name = "hpet",
      .ids = hpet_device_ids,
      .ops = {
            .add = hpet_acpi_add,
            .remove = hpet_acpi_remove,
            },
};

static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };

static int __init hpet_init(void)
{
      int result;

      result = misc_register(&hpet_misc);
      if (result < 0)
            return -ENODEV;

      sysctl_header = register_sysctl_table(dev_root);

      result = acpi_bus_register_driver(&hpet_acpi_driver);
      if (result < 0) {
            if (sysctl_header)
                  unregister_sysctl_table(sysctl_header);
            misc_deregister(&hpet_misc);
            return result;
      }

      return 0;
}

static void __exit hpet_exit(void)
{
      acpi_bus_unregister_driver(&hpet_acpi_driver);

      if (sysctl_header)
            unregister_sysctl_table(sysctl_header);
      misc_deregister(&hpet_misc);

      return;
}

module_init(hpet_init);
module_exit(hpet_exit);
MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
MODULE_LICENSE("GPL");

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