70 lines
2.3 KiB
C
70 lines
2.3 KiB
C
/*
|
|
<:copyright-BRCM:2011:GPL/GPL:standard
|
|
|
|
Copyright (c) 2011 Broadcom Corporation
|
|
All Rights Reserved
|
|
|
|
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 (the "GPL").
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
|
|
A copy of the GPL is available at http://www.broadcom.com/licenses/GPLv2.php, or by
|
|
writing to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
Boston, MA 02111-1307, USA.
|
|
|
|
:>
|
|
*/
|
|
|
|
#if defined(CONFIG_MIPS_BRCM) && defined(BCM_KF_TSTAMP)
|
|
#ifndef _BCM_TSTAMP_H_
|
|
#define _BCM_TSTAMP_H_
|
|
|
|
#include <linux/types.h>
|
|
|
|
/*
|
|
* This is a just a simple set of utility functions for measuring
|
|
* small amounts of time (<20 seconds) using the MIPS c0 counter.
|
|
* The main limitation with this implementation is that the c0 counter
|
|
* will roll over about every 21 seconds, so measurements of time that
|
|
* are longer than 20 seconds will be unreliable.
|
|
* These functions maintain no state (other than the initial multipliers
|
|
* and divisors based on clock speed), so no SMP locking is needed to
|
|
* use these functions.
|
|
* It is OK to read a starting timestamp on one CPU, and then read the
|
|
* ending timestamp on the other. The c0 counters of both CPU's are
|
|
* within about 20 cycles of each other, and bcm_tstamp_delta() tries
|
|
* to detect if a migration plus read of a slightly behind end timestamp
|
|
* has happened (seems extremely unlikely though). In this case, it
|
|
* returns 1 cycle (instead of 4 billion cycles, which is unlikely unless
|
|
* you are measuring something that is close to 20 seconds long.)
|
|
*/
|
|
|
|
/** Get current timestamp
|
|
*/
|
|
u32 bcm_tstamp_read(void);
|
|
|
|
/** Return the number of cycles elapsed between start and end.
|
|
*/
|
|
u32 bcm_tstamp_delta(u32 start, u32 end);
|
|
|
|
/** Return the number of cycles elapsed between start and now.
|
|
*/
|
|
u32 bcm_tstamp_elapsed(u32 start);
|
|
|
|
/** Convert a timestamp to microseconds.
|
|
*/
|
|
u32 bcm_tstamp2us(u32 i);
|
|
|
|
/** Convert a timestamp to nanoseconds. Note 64 bit return val.
|
|
*/
|
|
u64 bcm_tstamp2ns(u32 i);
|
|
|
|
#endif /* _BCM_TSTAMP_H_ */
|
|
#endif /* defined(CONFIG_MIPS_BRCM) && defined(BCM_KF_TSTAMP) */
|