105 lines
3.5 KiB
C
105 lines
3.5 KiB
C
/*
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* Copyright (c) 2011 Aeroflex Gaisler
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*
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* BSD license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef _LINUX_JIFFIES_H
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#define _LINUX_JIFFIES_H
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#include <asm-leon/types.h>
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#include <asm-leon/clock.h>
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#include <asm-leon/linkage.h>
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/* Suppose we want to devide two numbers NOM and DEN: NOM/DEN, the we can
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* improve accuracy by shifting LSH bits, hence calculating:
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* (NOM << LSH) / DEN
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* This however means trouble for large NOM, because (NOM << LSH) may no
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* longer fit in 32 bits. The following way of calculating this gives us
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* some slack, under the following conditions:
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* - (NOM / DEN) fits in (32 - LSH) bits.
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* - (NOM % DEN) fits in (32 - LSH) bits.
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*/
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#define SH_DIV(NOM,DEN,LSH) ( ((NOM / DEN) << LSH) \
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+ (((NOM % DEN) << LSH) + DEN / 2) / DEN)
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/* TICK_NSEC is the time between ticks in nsec assuming real ACTHZ */
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#define TICK_NSEC (SH_DIV (1000000UL * 1000, (HZ<<8), 8))
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/*
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* The 64-bit value is not volatile - you MUST NOT read it
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* without sampling the sequence number in xtime_lock.
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*/
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extern u64 jiffies_64;
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extern struct timespec xtime __attribute__ ((aligned (16)));
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#define jiffies (*((unsigned long *)(((unsigned long)(&jiffies_64))+4)))
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/*
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* These inlines deal with timer wrapping correctly. You are
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* strongly encouraged to use them
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* 1. Because people otherwise forget
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* 2. Because if the timer wrap changes in future you won't have to
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* alter your driver code.
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*
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* time_after(a,b) returns true if the time a is after time b.
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*
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* Do this with "<0" and ">=0" to only test the sign of the result. A
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* good compiler would generate better code (and a really good compiler
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* wouldn't care). Gcc is currently neither.
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*/
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#define time_after(a,b) \
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(typecheck(unsigned long, a) && \
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typecheck(unsigned long, b) && \
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((long)(b) - (long)(a) < 0))
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#define time_before(a,b) time_after(b,a)
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#define time_after_eq(a,b) \
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(typecheck(unsigned long, a) && \
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typecheck(unsigned long, b) && \
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((long)(a) - (long)(b) >= 0))
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#define time_before_eq(a,b) time_after_eq(b,a)
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/*
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* Have the 32 bit jiffies value wrap 5 minutes after boot
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* so jiffies wrap bugs show up earlier.
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*/
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#define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ))
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static inline void
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set_normalized_timespec (struct timespec *ts, time_t sec, long nsec)
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{
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while (nsec > NSEC_PER_SEC)
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{
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nsec -= NSEC_PER_SEC;
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++sec;
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}
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while (nsec < 0)
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{
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nsec += NSEC_PER_SEC;
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--sec;
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}
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ts->tv_sec = sec;
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ts->tv_nsec = nsec;
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}
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#endif
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