Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 994 insertions, 0 deletions

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
new file mode 100644
index 0000000..5ec732e
--- /dev/null
+++ b/drivers/char/hpet.c
@@ -0,0 +1,994 @@
+/*
+ * 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/config.h>
+#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/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 <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/labs/platcomp/hpet/hpetspec.htm
+ */
+#define	HPET_USER_FREQ	(64)
+#define	HPET_DRIFT	(500)
+
+static u32 hpet_ntimer, hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
+
+/* 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 time_interpolator *hp_interpolator;
+	unsigned long hp_period;
+	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
+
+#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
+
+#ifndef readq
+static unsigned long long __inline readq(void __iomem *addr)
+{
+	return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
+}
+#endif
+
+#ifndef writeq
+static void __inline 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 pt_regs *regs)
+{
+	struct hpet_dev *devp;
+	unsigned long isr;
+
+	devp = data;
+
+	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);
+	}
+
+	isr = (1 << (devp - devp->hd_hpets->hp_dev));
+	writeq(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);
+	addr = __pa(addr);
+
+	if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
+					PAGE_SIZE, vma->vm_page_prot)) {
+		printk(KERN_ERR "remap_pfn_range failed in hpet.c\n");
+		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;
+
+	v = readq(&timer->hpet_config);
+	spin_lock_irq(&hpet_lock);
+
+	if (devp->hd_flags & HPET_IE) {
+		spin_unlock_irq(&hpet_lock);
+		return -EBUSY;
+	}
+
+	devp->hd_flags |= HPET_IE;
+	spin_unlock_irq(&hpet_lock);
+
+	t = readq(&timer->hpet_config);
+	irq = devp->hd_hdwirq;
+
+	if (irq) {
+		sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
+
+		if (request_irq
+		    (irq, hpet_interrupt, SA_INTERRUPT, 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);
+	}
+
+	isr = (1 << (devp - hpets->hp_dev));
+	writeq(isr, &hpet->hpet_isr);
+	writeq(g, &timer->hpet_config);
+	local_irq_restore(flags);
+
+	return 0;
+}
+
+static inline unsigned long hpet_time_div(unsigned long dis)
+{
+	unsigned long long m = 1000000000000000ULL;
+
+	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;
+
+			info.hi_ireqfreq = hpet_time_div(hpetp->hp_period *
+							 devp->hd_ireqfreq);
+			info.hi_flags =
+			    readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
+			info.hi_hpet = devp->hd_hpets->hp_which;
+			info.hi_timer = devp - devp->hd_hpets->hp_dev;
+			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 & (arg - 1)) {
+			err = -EINVAL;
+			break;
+		}
+
+		devp->hd_ireqfreq = hpet_time_div(hpetp->hp_period * arg);
+	}
+
+	return err;
+}
+
+static 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,
+};
+
+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;
+	}
+
+	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 = 1,
+	 .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 = 1,
+	 .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;
+
+static void hpet_register_interpolator(struct hpets *hpetp)
+{
+#ifdef	CONFIG_TIME_INTERPOLATION
+	struct time_interpolator *ti;
+
+	ti = kmalloc(sizeof(*ti), GFP_KERNEL);
+	if (!ti)
+		return;
+
+	memset(ti, 0, sizeof(*ti));
+	ti->source = TIME_SOURCE_MMIO64;
+	ti->shift = 10;
+	ti->addr = &hpetp->hp_hpet->hpet_mc;
+	ti->frequency = hpet_time_div(hpets->hp_period);
+	ti->drift = ti->frequency * HPET_DRIFT / 1000000;
+	ti->mask = -1;
+
+	hpetp->hp_interpolator = ti;
+	register_time_interpolator(ti);
+#endif
+}
+
+/*
+ * 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 = hpets->hp_hpet;
+	t = read_counter(&timer->hpet_compare);
+
+	i = 0;
+	count = hpet_time_div(hpetp->hp_period * 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 = (struct hpets *)0;
+	unsigned long ns;
+
+	/*
+	 * hpet_alloc can be called by platform dependent code.
+	 * if platform dependent code has allocated the hpet
+	 * ACPI also reports hpet, then we catch it here.
+	 */
+	for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
+		if (hpetp->hp_hpet == hdp->hd_address)
+			return 0;
+
+	siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
+				      sizeof(struct hpet_dev));
+
+	hpetp = kmalloc(siz, GFP_KERNEL);
+
+	if (!hpetp)
+		return -ENOMEM;
+
+	memset(hpetp, 0, siz);
+
+	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;
+
+	hpetp->hp_period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
+	    HPET_COUNTER_CLK_PERIOD_SHIFT;
+
+	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");
+
+	ns = hpetp->hp_period;	/* femptoseconds, 10^-15 */
+	do_div(ns, 1000000);	/* convert to nanoseconds, 10^-9 */
+	printk(KERN_INFO "hpet%d: %ldns tick, %d %d-bit timers\n",
+		hpetp->hp_which, ns, hpetp->hp_ntimer,
+		cap & HPET_COUNTER_SIZE_MASK ? 64 : 32);
+
+	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++, hpet_ntimer++, devp++) {
+		unsigned long v;
+		struct hpet_timer __iomem *timer;
+
+		timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
+		v = readq(&timer->hpet_config);
+
+		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);
+	hpet_register_interpolator(hpetp);
+
+	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;
+	struct hpets *hpetp;
+
+	hdp = data;
+
+	status = acpi_resource_to_address64(res, &addr);
+
+	if (ACPI_SUCCESS(status)) {
+		unsigned long size;
+
+		size = addr.max_address_range - addr.min_address_range + 1;
+		hdp->hd_phys_address = addr.min_address_range;
+		hdp->hd_address = ioremap(addr.min_address_range, size);
+
+		for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
+			if (hpetp->hp_hpet == hdp->hd_address)
+				return -EBUSY;
+	} else if (res->id == ACPI_RSTYPE_EXT_IRQ) {
+		struct acpi_resource_ext_irq *irqp;
+		int i;
+
+		irqp = &res->data.extended_irq;
+
+		if (irqp->number_of_interrupts > 0) {
+			hdp->hd_nirqs = irqp->number_of_interrupts;
+
+			for (i = 0; i < hdp->hd_nirqs; i++)
+				hdp->hd_irq[i] =
+				    acpi_register_gsi(irqp->interrupts[i],
+						      irqp->edge_level,
+						      irqp->active_high_low);
+		}
+	}
+
+	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 interpolator, dealloc mem, etc */
+	return -EINVAL;
+}
+
+static struct acpi_driver hpet_acpi_driver = {
+	.name = "hpet",
+	.ids = "PNP0103",
+	.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, 0);
+
+	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");