[PATCH] HPET driver

The driver supports the High Precision Event Timer.  The driver has adopted
a similar API to the Real Time Clock driver.  It can support any number of
HPET devices and the maximum number of timers per HPET device.  For further
information look at the documentation in the patch.

Thanks to Venki at Intel for testing the driver on X86 hardware with HPET.

HPET documentation is available at http://www.intel.com/design/chipsets/datashts/252516.htmSigned-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/filesystems/proc.txt

@@ -201,7 +201,7 @@ Table 1-3: Kernel info in /proc
  devices     Available devices (block and character)           
  dma         Used DMS channels                                 
  filesystems Supported filesystems                             
- driver	     Various drivers grouped here, currently rtc	(2.4)
+ driver	     Various drivers grouped here, currently rtc (2.4) and hpet (2.6)
  execdomains Execdomains, related to security			(2.4)
  fb	     Frame Buffer devices				(2.4)
  fs	     File system parameters, currently nfs/exports	(2.4)

Documentation/hpet.txt

+		High Precision Event Timer Driver for Linux
+
+The High Precision Event Timer (HPET) hardware is the future replacement for the 8254 and Real
+Time Clock (RTC) periodic timer functionality.  Each HPET can have up two 32 timers.  It is possible
+to configure the first two timers as legacy replacements for 8254 and RTC periodic.  A specification
+done by INTEL and Microsoft can be found at http://www.intel.com/labs/platcomp/hpet/hpetspec.htm.
+
+The driver supports detection of HPET driver allocation and initialization of the HPET before the
+driver module_init routine is called.  This enables platform code which uses timer 0 or 1 as the
+main timer to intercept HPET initialization.  An example of this initialization can be found in
+arch/i386/kernel/time_hpet.c.
+
+The driver provides two APIs which are very similar to the API found in the rtc.c driver.
+There is a user space API and a kernel space API.  An example user space program is provided
+below.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <memory.h>
+#include <malloc.h>
+#include <time.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <linux/hpet.h>
+
+
+extern void hpet_open_close(int, const char **);
+extern void hpet_info(int, const char **);
+extern void hpet_poll(int, const char **);
+extern void hpet_fasync(int, const char **);
+extern void hpet_read(int, const char **);
+
+#include <sys/poll.h>
+#include <sys/ioctl.h>
+#include <signal.h>
+
+struct hpet_command {
+	char		*command;
+	void		(*func)(int argc, const char ** argv);
+} hpet_command[] = {
+	{
+		"open-close",
+		hpet_open_close
+	},
+	{
+		"info",
+		hpet_info
+	},
+	{
+		"poll",
+		hpet_poll
+	},
+	{
+		"fasync",
+		hpet_fasync
+	},
+};
+
+int
+main(int argc, const char ** argv)
+{
+	int	i;
+
+	argc--;
+	argv++;
+
+	if (!argc) {
+		fprintf(stderr, "-hpet: requires command\n");
+		return -1;
+	}
+
+
+	for (i = 0; i < (sizeof (hpet_command) / sizeof (hpet_command[0])); i++)
+		if (!strcmp(argv[0], hpet_command[i].command)) {
+			argc--;
+			argv++;
+			fprintf(stderr, "-hpet: executing %s\n",
+				hpet_command[i].command);
+			hpet_command[i].func(argc, argv);
+			return 0;
+		}
+
+	fprintf(stderr, "do_hpet: command %s not implemented\n", argv[0]);
+
+	return -1;
+}
+
+void
+hpet_open_close(int argc, const char **argv)
+{
+	int	fd;
+
+	if (argc != 1) {
+		fprintf(stderr, "hpet_open_close: device-name\n");
+		return;
+	}
+
+	fd = open(argv[0], O_RDWR);
+	if (fd < 0)
+		fprintf(stderr, "hpet_open_close: open failed\n");
+	else
+		close(fd);
+
+	return;
+}
+
+void
+hpet_info(int argc, const char **argv)
+{
+}
+
+void
+hpet_poll(int argc, const char **argv)
+{
+	unsigned long		freq;
+	int			iterations, i, fd;
+	struct pollfd		pfd;
+	struct hpet_info	info;
+	struct timeval		stv, etv;
+	struct timezone		tz;
+	long			usec;
+
+	if (argc != 3) {
+		fprintf(stderr, "hpet_poll: device-name freq iterations\n");
+		return;
+	}
+
+	freq = atoi(argv[1]);
+	iterations = atoi(argv[2]);
+
+	fd = open(argv[0], O_RDWR);
+
+	if (fd < 0) {
+		fprintf(stderr, "hpet_poll: open of %s failed\n", argv[0]);
+		return;
+	}
+
+	if (ioctl(fd, HPET_IRQFREQ, freq) < 0) {
+		fprintf(stderr, "hpet_poll: HPET_IRQFREQ failed\n");
+		goto out;
+	}
+
+	if (ioctl(fd, HPET_INFO, &info) < 0) {
+		fprintf(stderr, "hpet_poll: failed to get info\n");
+		goto out;
+	}
+
+	fprintf(stderr, "hpet_poll: info.hi_flags 0x%lx\n", info.hi_flags);
+
+	if (info.hi_flags && (ioctl(fd, HPET_EPI, 0) < 0)) {
+		fprintf(stderr, "hpet_poll: HPET_EPI failed\n");
+		goto out;
+	}
+
+	if (ioctl(fd, HPET_IE_ON, 0) < 0) {
+		fprintf(stderr, "hpet_poll, HPET_IE_ON failed\n");
+		goto out;
+	}
+
+	pfd.fd = fd;
+	pfd.events = POLLIN;
+
+	for (i = 0; i < iterations; i++) {
+		pfd.revents = 0;
+		gettimeofday(&stv, &tz);
+		if (poll(&pfd, 1, -1) < 0)
+			fprintf(stderr, "hpet_poll: poll failed\n");
+		else {
+			long 	data;
+
+			gettimeofday(&etv, &tz);
+			usec = stv.tv_sec * 1000000 + stv.tv_usec;
+			usec = (etv.tv_sec * 1000000 + etv.tv_usec) - usec;
+
+			fprintf(stderr,
+				"hpet_poll: expired time = 0x%lx\n", usec);
+
+			fprintf(stderr, "hpet_poll: revents = 0x%x\n",
+				pfd.revents);
+
+			if (read(fd, &data, sizeof(data)) != sizeof(data)) {
+				fprintf(stderr, "hpet_poll: read failed\n");
+			}
+			else
+				fprintf(stderr, "hpet_poll: data 0x%lx\n",
+					data);
+		}
+	}
+
+out:
+	close(fd);
+	return;
+}
+
+static int hpet_sigio_count;
+
+static void
+hpet_sigio(int val)
+{
+	fprintf(stderr, "hpet_sigio: called\n");
+	hpet_sigio_count++;
+}
+
+void
+hpet_fasync(int argc, const char **argv)
+{
+	unsigned long		freq;
+	int			iterations, i, fd, value;
+	sig_t			oldsig;
+	struct hpet_info	info;
+
+	hpet_sigio_count = 0;
+	fd = -1;
+
+	if ((oldsig = signal(SIGIO, hpet_sigio)) == SIG_ERR) {
+		fprintf(stderr, "hpet_fasync: failed to set signal handler\n");
+		return;
+	}
+
+	if (argc != 3) {
+		fprintf(stderr, "hpet_fasync: device-name freq iterations\n");
+		goto out;
+	}
+
+	fd = open(argv[0], O_RDWR);
+
+	if (fd < 0) {
+		fprintf(stderr, "hpet_fasync: failed to open %s\n", argv[0]);
+		return;
+	}
+
+
+	if ((fcntl(fd, F_SETOWN, getpid()) == 1) ||
+		((value = fcntl(fd, F_GETFL)) == 1) ||
+		(fcntl(fd, F_SETFL, value | O_ASYNC) == 1)) {
+		fprintf(stderr, "hpet_fasync: fcntl failed\n");
+		goto out;
+	}
+
+	freq = atoi(argv[1]);
+	iterations = atoi(argv[2]);
+
+	if (ioctl(fd, HPET_IRQFREQ, freq) < 0) {
+		fprintf(stderr, "hpet_fasync: HPET_IRQFREQ failed\n");
+		goto out;
+	}
+
+	if (ioctl(fd, HPET_INFO, &info) < 0) {
+		fprintf(stderr, "hpet_fasync: failed to get info\n");
+		goto out;
+	}
+
+	fprintf(stderr, "hpet_fasync: info.hi_flags 0x%lx\n", info.hi_flags);
+
+	if (info.hi_flags && (ioctl(fd, HPET_EPI, 0) < 0)) {
+		fprintf(stderr, "hpet_fasync: HPET_EPI failed\n");
+		goto out;
+	}
+
+	if (ioctl(fd, HPET_IE_ON, 0) < 0) {
+		fprintf(stderr, "hpet_fasync, HPET_IE_ON failed\n");
+		goto out;
+	}
+
+	for (i = 0; i < iterations; i++) {
+		(void) pause();
+		fprintf(stderr, "hpet_fasync: count = %d\n", hpet_sigio_count);
+	}
+
+out:
+	signal(SIGIO, oldsig);
+
+	if (fd >= 0)
+		close(fd);
+
+	return;
+}
+
+The kernel API has three interfaces exported from the driver:
+
+	hpet_register(struct hpet_task *tp, int periodic)
+	hpet_unregister(struct hpet_task *tp)
+	hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
+
+The kernel module using this interface fills in the ht_func and ht_data members of the
+hpet_task structure before calling hpet_register.  hpet_control simply vectors to the hpet_ioctl
+routine and has the same commands and respective arguments as the user API.  hpet_unregister
+is used to terminate usage of the HPET timer reserved by hpet_register.
+
+

arch/i386/Kconfig

@@ -436,7 +436,8 @@ config HPET_TIMER
 	  Choose N to continue using the legacy 8254 timer.
 
 config HPET_EMULATE_RTC
-	def_bool HPET_TIMER && RTC=y
+	bool "Provide RTC interrupt"
+	depends on HPET_TIMER && RTC=y
 
 config SMP
 	bool "Symmetric multi-processing support"

arch/i386/kernel/time_hpet.c

@@ -21,6 +21,7 @@
 #include <linux/config.h>
 
 #include <asm/hpet.h>
+#include <linux/hpet.h>
 
 unsigned long hpet_period;	/* fsecs / HPET clock */
 unsigned long hpet_tick;	/* hpet clks count per tick */
@@ -135,6 +136,51 @@ int __init hpet_enable(void)
 	hpet_writel(cfg, HPET_CFG);
 
 	use_hpet = 1;
+
+#ifdef	CONFIG_HPET
+	{
+		struct hpet_data	hd;
+		unsigned int 		ntimer;
+
+		memset(&hd, 0, sizeof (hd));
+
+		ntimer = hpet_readl(HPET_ID);
+		ntimer = (ntimer & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT;
+		ntimer++;
+
+		/*
+		 * Register with driver.
+		 * Timer0 and Timer1 is used by platform.
+		 */
+		hd.hd_address = hpet_virt_address;
+		hd.hd_nirqs = ntimer;
+		hd.hd_flags = HPET_DATA_PLATFORM;
+#ifndef	CONFIG_HPET_EMULATE_RTC
+		hd.hd_state = 0x1;
+#else
+		hd.hd_state = 0x3;
+#endif
+		hd.hd_irq[0] = HPET_LEGACY_8254;
+		hd.hd_irq[1] = HPET_LEGACY_RTC;
+		if (ntimer > 2) {
+			struct hpet		*hpet;
+			struct hpet_timer	*timer;
+			int			i;
+
+			hpet = (struct hpet *) hpet_virt_address;
+
+			for (i = 2, timer = &hpet->hpet_timers[2]; i < ntimer;
+				timer++, i++)
+				hd.hd_irq[i] = (timer->hpet_config &
+					Tn_INT_ROUTE_CNF_MASK) >>
+					Tn_INT_ROUTE_CNF_SHIFT;
+
+		}
+
+		hpet_alloc(&hd);
+	}
+#endif
+
 #ifdef CONFIG_X86_LOCAL_APIC
 	wait_timer_tick = wait_hpet_tick;
 #endif

drivers/char/Kconfig

@@ -957,6 +957,33 @@ config RAW_DRIVER
           kernels.  Applications should simply open the device (eg /dev/hda1)
           with the O_DIRECT flag.
 
+config HPET
+	bool "HPET - High Precision Event Timer" if (X86 || IA64)
+	default n
+	depends on ACPI
+	help
+	  If you say Y here, you will have a device named "/dev/hpet/XX" for
+	  each timer supported by the HPET.  The timers are
+	  non-periodioc and/or periodic.
+
+config HPET_RTC_IRQ
+	bool "HPET Control RTC IRQ" if !HPET_EMULATE_RTC
+	default n
+	depends on HPET
+	help
+	  If you say Y here, you will disable RTC_IRQ in drivers/char/rtc.c. It
+	  is assumed the platform called hpet_alloc with the RTC IRQ values for
+	  the HPET timers.
+
+config HPET_NOMMAP
+	bool "HPET - Control mmap capability."
+	default n
+	depends on HPET
+	help
+	  If you say Y here, then the mmap interface for the HPET driver returns ENOSYS.
+	  Some hardware implementations might not want all the memory in the page the
+	  HPET control registers reside to be exposed.
+
 config MAX_RAW_DEVS
 	int "Maximum number of RAW devices to support (1-8192)"
 	depends on RAW_DRIVER

drivers/char/Makefile

@@ -54,6 +54,7 @@ obj-$(CONFIG_R3964) += n_r3964.o
 obj-$(CONFIG_APPLICOM) += applicom.o
 obj-$(CONFIG_SONYPI) += sonypi.o
 obj-$(CONFIG_RTC) += rtc.o
+obj-$(CONFIG_HPET) += hpet.o
 obj-$(CONFIG_GEN_RTC) += genrtc.o
 obj-$(CONFIG_EFI_RTC) += efirtc.o
 ifeq ($(CONFIG_GENERIC_NVRAM),y)

drivers/char/hpet.c

+/*
+ * Intel & MS High Precision Event Timer Implementation.
+ * Contributors:
+ *	Venki Pallipadi
+ * 	Bob Picco
+ */
+
+#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 <asm/current.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/bitops.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 spinlock_t hpet_lock = SPIN_LOCK_UNLOCKED;
+/* A lock for concurrent intermodule access to hpet and isr hpet activity. */
+static spinlock_t hpet_task_lock = SPIN_LOCK_UNLOCKED;
+
+struct hpet_dev {
+	struct hpets *hd_hpets;
+	struct hpet *hd_hpet;
+	struct hpet_timer *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;
+};
+
+struct hpets {
+	struct hpets *hp_next;
+	struct hpet *hp_hpet;
+	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 *addr)
+{
+	return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
+}
+#endif
+
+#ifndef writeq
+static void __inline writeq(unsigned long long v, void *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;
+
+	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 *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);
+
+	do {
+		__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();
+
+	} while (1);
+
+	retval = put_user(data, (unsigned long *)buf);
+	if (!retval)
+		retval = sizeof(unsigned long);
+      out:
+	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_NOMMAP
+	return -ENOSYS;
+#else
+	struct hpet_dev *devp;
+	unsigned long addr;
+
+	if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
+		return -EINVAL;
+
+	if (vma->vm_flags & VM_WRITE)
+		return -EPERM;
+
+	devp = file->private_data;
+	addr = (unsigned long)devp->hd_hpet;
+
+	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 (remap_page_range
+	    (vma, vma->vm_start, addr, PAGE_SIZE, vma->vm_page_prot)) {
+		printk(KERN_ERR "remap_page_range failed in hpet.c\n");
+		return -EAGAIN;
+	}
+
+	return 0;
+#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 *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 = 0;
+	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 *timer;
+	struct hpet *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) {
+		char name[7];
+
+		sprintf(name, "hpet%d", (int)(devp - hpetp->hp_dev));
+
+		if (request_irq
+		    (irq, hpet_interrupt, SA_INTERRUPT, 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 *timer;
+	struct hpet *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 *)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 *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 = 0, 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 = 0;
+				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 *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 = 0;
+	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);
+}
+
+#ifdef	CONFIG_TIME_INTERPOLATION
+
+static unsigned long hpet_offset, last_wall_hpet;
+static long hpet_nsecs_per_cycle, hpet_cycles_per_sec;
+
+static unsigned long hpet_getoffset(void)
+{
+	return hpet_offset + (read_counter(&hpets->hp_hpet->hpet_mc) -
+			      last_wall_hpet) * hpet_nsecs_per_cycle;
+}
+
+static void hpet_update(long delta)
+{
+	unsigned long mc;
+	unsigned long offset;
+
+	mc = read_counter(&hpets->hp_hpet->hpet_mc);
+	offset = hpet_offset + (mc - last_wall_hpet) * hpet_nsecs_per_cycle;
+
+	if (delta < 0 || (unsigned long)delta < offset)
+		hpet_offset = offset - delta;
+	else
+		hpet_offset = 0;
+	last_wall_hpet = mc;
+}
+
+static void hpet_reset(void)
+{
+	hpet_offset = 0;
+	last_wall_hpet = read_counter(&hpets->hp_hpet->hpet_mc);
+}
+
+static struct time_interpolator hpet_interpolator = {
+	.get_offset = hpet_getoffset,
+	.update = hpet_update,
+	.reset = hpet_reset
+};
+
+#endif
+
+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_start(struct seq_file *s, loff_t * pos)
+{
+	struct hpets *hpetp;
+	loff_t n;
+
+	for (n = *pos, hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
+		if (!n--)
+			return hpetp;
+
+	return 0;
+}
+
+static void *hpet_next(struct seq_file *s, void *v, loff_t * pos)
+{
+	struct hpets *hpetp;
+
+	hpetp = v;
+	++*pos;
+	return hpetp->hp_next;
+}
+
+static void hpet_stop(struct seq_file *s, void *v)
+{
+	return;
+}
+
+static int hpet_show(struct seq_file *s, void *v)
+{
+	struct hpets *hpetp;
+	struct hpet *hpet;
+	u64 cap, vendor, period;
+
+	hpetp = v;
+	hpet = hpetp->hp_hpet;
+
+	cap = readq(&hpet->hpet_cap);
+	period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
+	    HPET_COUNTER_CLK_PERIOD_SHIFT;
+	vendor = (cap & HPET_VENDOR_ID_MASK) >> HPET_VENDOR_ID_SHIFT;
+
+	seq_printf(s,
+		   "HPET%d period = %d 10**-15  vendor = 0x%x number timer = %d\n",
+		   hpetp->hp_which, (u32) period, (u32) vendor,
+		   hpetp->hp_ntimer);
+
+	return 0;
+}
+
+static struct seq_operations hpet_seq_ops = {
+	.start = hpet_start,
+	.next = hpet_next,
+	.stop = hpet_stop,
+	.show = hpet_show
+};
+
+static int hpet_proc_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &hpet_seq_ops);
+}
+
+static struct file_operations hpet_proc_fops = {
+	.open = hpet_proc_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release
+};
+
+/*
+ * 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 __init hpet_calibrate(struct hpets *hpetp)
+{
+	struct hpet_timer *timer;
+	unsigned long t, m, count, i, flags, start;
+	struct hpet_dev *devp;
+	int j;
+	struct hpet *hpet;
+
+	for (timer = 0, 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 __init hpet_alloc(struct hpet_data *hdp)
+{
+	u64 cap, mcfg;
+	struct hpet_dev *devp;
+	u32 i, ntimer;
+	struct hpets *hpetp;
+	size_t siz;
+	struct hpet *hpet;
+	static struct hpets *last __initdata = (struct hpets *)0;
+
+	/*
+	 * 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 == (struct 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 = (struct hpet *)hdp->hd_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;
+
+	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 *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);
+
+	return 0;
+}
+
+static acpi_status __init 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_address =
+		    (unsigned long)ioremap(addr.min_address_range, size);
+
+		for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
+			if (hpetp->hp_hpet == (struct 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++)
+#ifdef	CONFIG_IA64
+				hdp->hd_irq[i] =
+				    acpi_register_gsi(irqp->interrupts[i],
+						      irqp->edge_level,
+						      irqp->active_high_low);
+#else
+				hdp->hd_irq[i] = irqp->interrupts[i];
+#endif
+		}
+	}
+
+	return AE_OK;
+}
+
+static int __init 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 __init hpet_acpi_remove(struct acpi_device *device, int type)
+{
+	return 0;
+}
+
+static struct acpi_driver hpet_acpi_driver __initdata = {
+	.name = "hpet",
+	.class = "",
+	.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)
+{
+	struct proc_dir_entry *entry;
+
+	(void)acpi_bus_register_driver(&hpet_acpi_driver);
+
+	if (hpets) {
+		if (misc_register(&hpet_misc))
+			return -ENODEV;
+
+		entry = create_proc_entry("driver/hpet", 0, 0);
+
+		if (entry)
+			entry->proc_fops = &hpet_proc_fops;
+
+		sysctl_header = register_sysctl_table(dev_root, 0);
+
+#ifdef	CONFIG_TIME_INTERPOLATION
+		{
+			struct hpet *hpet;
+
+			hpet = hpets->hp_hpet;
+			hpet_cycles_per_sec = hpet_time_div(hpets->hp_period);
+			hpet_interpolator.frequency = hpet_cycles_per_sec;
+			hpet_interpolator.drift = hpet_cycles_per_sec *
+			    HPET_DRIFT / 1000000;
+			hpet_nsecs_per_cycle = 1000000000 / hpet_cycles_per_sec;
+			register_time_interpolator(&hpet_interpolator);
+		}
+#endif
+		return 0;
+	} else
+		return -ENODEV;
+}
+
+static void __exit hpet_exit(void)
+{
+	acpi_bus_unregister_driver(&hpet_acpi_driver);
+
+	if (hpets) {
+		unregister_sysctl_table(sysctl_header);
+		remove_proc_entry("driver/hpet", NULL);
+	}
+
+	return;
+}
+
+module_init(hpet_init);
+module_exit(hpet_exit);
+MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
+MODULE_LICENSE("GPL");

drivers/char/rtc.c

@@ -97,6 +97,11 @@ static unsigned long rtc_port;
 static int rtc_irq = PCI_IRQ_NONE;
 #endif
 
+#ifdef	CONFIG_HPET_RTC_IRQ
+#undef	RTC_IRQ
+#define	RTC_IRQ	0
+#endif
+
 #ifdef RTC_IRQ
 static int rtc_has_irq = 1;
 #endif

include/asm-i386/hpet.h

@@ -57,9 +57,12 @@
 #define HPET_ID_LEGSUP	0x00008000
 #define HPET_ID_NUMBER	0x00001f00
 #define HPET_ID_REV	0x000000ff
+#define	HPET_ID_NUMBER_SHIFT	8
 
 #define HPET_CFG_ENABLE	0x001
 #define HPET_CFG_LEGACY	0x002
+#define	HPET_LEGACY_8254	2
+#define	HPET_LEGACY_RTC		8
 
 #define HPET_TN_ENABLE		0x004
 #define HPET_TN_PERIODIC	0x008

include/linux/hpet.h

+#ifndef	__HPET__
+#define	__HPET__ 1
+
+/*
+ * Offsets into HPET Registers
+ */
+
+struct hpet {
+	u64 hpet_cap;		/* capabilities */
+	u64 res0;		/* reserved */
+	u64 hpet_config;	/* configuration */
+	u64 res1;		/* reserved */
+	u64 hpet_isr;		/* interrupt status reg */
+	u64 res2[25];		/* reserved */
+	union {			/* main counter */
+		u64 _hpet_mc64;
+		u32 _hpet_mc32;
+		unsigned long _hpet_mc;
+	} _u0;
+	u64 res3;		/* reserved */
+	struct hpet_timer {
+		u64 hpet_config;	/* configuration/cap */
+		union {		/* timer compare register */
+			u64 _hpet_hc64;
+			u32 _hpet_hc32;
+			unsigned long _hpet_compare;
+		} _u1;
+		u64 hpet_fsb[2];	/* FSB route */
+	} hpet_timers[1];
+};
+
+#define	hpet_mc		_u0._hpet_mc
+#define	hpet_compare	_u1._hpet_compare
+
+#define	HPET_MAX_TIMERS	(32)
+
+/*
+ * HPET general capabilities register
+ */
+
+#define	HPET_COUNTER_CLK_PERIOD_MASK	(0xffffffff00000000ULL)
+#define	HPET_COUNTER_CLK_PERIOD_SHIFT	(32UL)
+#define	HPET_VENDOR_ID_MASK		(0x00000000ffff0000ULL)
+#define	HPET_VENDOR_ID_SHIFT		(16ULL)
+#define	HPET_LEG_RT_CAP_MASK		(0x8000)
+#define	HPET_COUNTER_SIZE_MASK		(0x2000)
+#define	HPET_NUM_TIM_CAP_MASK		(0x1f00)
+#define	HPET_NUM_TIM_CAP_SHIFT		(8ULL)
+
+/*
+ * HPET general configuration register
+ */
+
+#define	HPET_LEG_RT_CNF_MASK		(2UL)
+#define	HPET_ENABLE_CNF_MASK		(1UL)
+
+/*
+ * HPET interrupt status register
+ */
+
+#define	HPET_ISR_CLEAR(HPET, TIMER)				\
+		(HPET)->hpet_isr |= (1UL << TIMER)
+
+/*
+ * Timer configuration register
+ */
+
+#define	Tn_INT_ROUTE_CAP_MASK		(0xffffffff00000000ULL)
+#define	Tn_INI_ROUTE_CAP_SHIFT		(32UL)
+#define	Tn_FSB_INT_DELCAP_MASK		(0x8000UL)
+#define	Tn_FSB_INT_DELCAP_SHIFT		(15)
+#define	Tn_FSB_EN_CNF_MASK		(0x4000UL)
+#define	Tn_FSB_EN_CNF_SHIFT		(14)
+#define	Tn_INT_ROUTE_CNF_MASK		(0x3e00UL)
+#define	Tn_INT_ROUTE_CNF_SHIFT		(9)
+#define	Tn_32MODE_CNF_MASK		(0x0100UL)
+#define	Tn_VAL_SET_CNF_MASK		(0x0040UL)
+#define	Tn_SIZE_CAP_MASK		(0x0020UL)
+#define	Tn_PER_INT_CAP_MASK		(0x0010UL)
+#define	Tn_TYPE_CNF_MASK		(0x0008UL)
+#define	Tn_INT_ENB_CNF_MASK		(0x0004UL)
+#define	Tn_INT_TYPE_CNF_MASK		(0x0002UL)
+
+/*
+ * Timer FSB Interrupt Route Register
+ */
+
+#define	Tn_FSB_INT_ADDR_MASK		(0xffffffff00000000ULL)
+#define	Tn_FSB_INT_ADDR_SHIFT		(32UL)
+#define	Tn_FSB_INT_VAL_MASK		(0x00000000ffffffffULL)
+
+struct hpet_info {
+	unsigned long hi_ireqfreq;	/* Hz */
+	unsigned long hi_flags;	/* information */
+	unsigned short hi_hpet;
+	unsigned short hi_timer;
+};
+
+#define	HPET_INFO_PERIODIC	0x0001	/* timer is periodic */
+
+#define	HPET_IE_ON	_IO('h', 0x01)	/* interrupt on */
+#define	HPET_IE_OFF	_IO('h', 0x02)	/* interrupt off */
+#define	HPET_INFO	_IOR('h', 0x03, struct hpet_info)
+#define	HPET_EPI	_IO('h', 0x04)	/* enable periodic */
+#define	HPET_DPI	_IO('h', 0x05)	/* disable periodic */
+#define	HPET_IRQFREQ	_IOW('h', 0x6, unsigned long)	/* IRQFREQ usec */
+
+/*
+ * exported interfaces
+ */
+
+struct hpet_task {
+	void (*ht_func) (void *);
+	void *ht_data;
+	void *ht_opaque;
+};
+
+struct hpet_data {
+	unsigned long hd_address;
+	unsigned short hd_nirqs;
+	unsigned short hd_flags;
+	unsigned int hd_state;	/* timer allocated */
+	unsigned int hd_irq[HPET_MAX_TIMERS];
+};
+
+#define	HPET_DATA_PLATFORM	0x0001	/* platform call to hpet_alloc */
+
+int hpet_alloc(struct hpet_data *);
+int hpet_register(struct hpet_task *, int);
+int hpet_unregister(struct hpet_task *);
+int hpet_control(struct hpet_task *, unsigned int, unsigned long);
+
+#endif				/* !__HPET__ */

include/linux/miscdevice.h

@@ -33,6 +33,7 @@
 #define SGI_STREAMS_KEYBOARD 150
 /* drivers/sgi/char/usema.c */
 #define SGI_USEMACLONE	     151
+#define	HPET_MINOR	     152
 
 #define TUN_MINOR	     200