hpet.c

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/*
 * 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 <[e-mail]>
 *
 * 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,