linux/drivers/char/uv_mmtimer.c

/*
 * Timer device implementation for SGI UV platform.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 2009 Silicon Graphics, Inc.  All rights reserved.
 *
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/ioctl.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/mmtimer.h>
#include <linux/miscdevice.h>
#include <linux/posix-timers.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/math64.h>

#include <asm/genapic.h>
#include <asm/uv/uv_hub.h>
#include <asm/uv/bios.h>
#include <asm/uv/uv.h>

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;

/* name of the device, usually in /dev */
#define UV_MMTIMER_NAME …
#define UV_MMTIMER_DESC …
#define UV_MMTIMER_VERSION …

static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd,
						unsigned long arg);
static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma);

/*
 * Period in femtoseconds (10^-15 s)
 */
static unsigned long uv_mmtimer_femtoperiod;

static const struct file_operations uv_mmtimer_fops = …;

/**
 * uv_mmtimer_ioctl - ioctl interface for /dev/uv_mmtimer
 * @file: file structure for the device
 * @cmd: command to execute
 * @arg: optional argument to command
 *
 * Executes the command specified by @cmd.  Returns 0 for success, < 0 for
 * failure.
 *
 * Valid commands:
 *
 * %MMTIMER_GETOFFSET - Should return the offset (relative to the start
 * of the page where the registers are mapped) for the counter in question.
 *
 * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15)
 * seconds
 *
 * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address
 * specified by @arg
 *
 * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter
 *
 * %MMTIMER_MMAPAVAIL - Returns 1 if registers can be mmap'd into userspace
 *
 * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it
 * in the address specified by @arg.
 */
static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd,
						unsigned long arg)
{ … }

/**
 * uv_mmtimer_mmap - maps the clock's registers into userspace
 * @file: file structure for the device
 * @vma: VMA to map the registers into
 *
 * Calls remap_pfn_range() to map the clock's registers into
 * the calling process' address space.
 */
static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma)
{ … }

static struct miscdevice uv_mmtimer_miscdev = …;


/**
 * uv_mmtimer_init - device initialization routine
 *
 * Does initial setup for the uv_mmtimer device.
 */
static int __init uv_mmtimer_init(void)
{ … }

module_init(…) …;