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/*
* 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) 2001 Silicon Graphics, Inc. All rights reserved.
*
* SGI Hi Resolution Clock
*
* SGI SN platforms provide a high resolution clock that is
* synchronized across all nodes. The clock can be memory mapped
* and directly read from user space.
*
* Access to the clock is thru the following:
* (error checking not shown)
*
* (Note: should library routines be provided to encapsulate this??)
*
* int fd:
* volatile long *clk;
*
* fd = open (HIRES_FULLNAME, O_RDONLY);
* clk = mmap(0, getpagesize(), PROT_READ, MAP_SHARED, fd, 0);
* clk += ioctl(fd, HIRES_IOCQGETOFFSET, 0);
*
* At this point, clk is a pointer to the high resolution clock.
*
* The clock period can be obtained via:
*
* long picosec_per_tick;
* picosec_per_tick = ioctl(fd, HIRES_IOCQGETPICOSEC, 0);
*/
#ifndef _ASM_IA64_SN_HIRES_CLOCK_H
#define _ASM_IA64_SN_HIRES_CLOCK_H
#define HIRES_BASENAME "sgi_hires_clock"
#define HIRES_FULLNAME "/dev/sgi_hires_clock"
#define HIRES_IOC_BASE 's'
/* Get page offset of hires timer */
#define HIRES_IOCQGETOFFSET _IO( HIRES_IOC_BASE, 0 )
/* get clock period in picoseconds per tick */
#define HIRES_IOCQGETPICOSEC _IO( HIRES_IOC_BASE, 1 )
/* get number of significant bits in clock counter */
#define HIRES_IOCQGETCLOCKBITS _IO( HIRES_IOC_BASE, 2 )
#endif /* _ASM_IA64_SN_HIRES_CLOCK_H */
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