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Diffstat (limited to 'libgloss/sparc_leon/asm-leon/jiffies.h')
-rw-r--r-- | libgloss/sparc_leon/asm-leon/jiffies.h | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/libgloss/sparc_leon/asm-leon/jiffies.h b/libgloss/sparc_leon/asm-leon/jiffies.h new file mode 100644 index 000000000..60b0e2701 --- /dev/null +++ b/libgloss/sparc_leon/asm-leon/jiffies.h @@ -0,0 +1,104 @@ +/* + * Copyright (c) 2011 Aeroflex Gaisler + * + * BSD license: + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + + +#ifndef _LINUX_JIFFIES_H +#define _LINUX_JIFFIES_H + +#include <asm-leon/types.h> +#include <asm-leon/clock.h> +#include <asm-leon/linkage.h> + +/* Suppose we want to devide two numbers NOM and DEN: NOM/DEN, the we can + * improve accuracy by shifting LSH bits, hence calculating: + * (NOM << LSH) / DEN + * This however means trouble for large NOM, because (NOM << LSH) may no + * longer fit in 32 bits. The following way of calculating this gives us + * some slack, under the following conditions: + * - (NOM / DEN) fits in (32 - LSH) bits. + * - (NOM % DEN) fits in (32 - LSH) bits. + */ +#define SH_DIV(NOM,DEN,LSH) ( ((NOM / DEN) << LSH) \ + + (((NOM % DEN) << LSH) + DEN / 2) / DEN) + +/* TICK_NSEC is the time between ticks in nsec assuming real ACTHZ */ +#define TICK_NSEC (SH_DIV (1000000UL * 1000, (HZ<<8), 8)) + +/* + * The 64-bit value is not volatile - you MUST NOT read it + * without sampling the sequence number in xtime_lock. + */ +extern u64 jiffies_64; +extern struct timespec xtime __attribute__ ((aligned (16))); +#define jiffies (*((unsigned long *)(((unsigned long)(&jiffies_64))+4))) + +/* + * These inlines deal with timer wrapping correctly. You are + * strongly encouraged to use them + * 1. Because people otherwise forget + * 2. Because if the timer wrap changes in future you won't have to + * alter your driver code. + * + * time_after(a,b) returns true if the time a is after time b. + * + * Do this with "<0" and ">=0" to only test the sign of the result. A + * good compiler would generate better code (and a really good compiler + * wouldn't care). Gcc is currently neither. + */ +#define time_after(a,b) \ + (typecheck(unsigned long, a) && \ + typecheck(unsigned long, b) && \ + ((long)(b) - (long)(a) < 0)) +#define time_before(a,b) time_after(b,a) + +#define time_after_eq(a,b) \ + (typecheck(unsigned long, a) && \ + typecheck(unsigned long, b) && \ + ((long)(a) - (long)(b) >= 0)) +#define time_before_eq(a,b) time_after_eq(b,a) + +/* + * Have the 32 bit jiffies value wrap 5 minutes after boot + * so jiffies wrap bugs show up earlier. + */ +#define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ)) + +static inline void +set_normalized_timespec (struct timespec *ts, time_t sec, long nsec) +{ + while (nsec > NSEC_PER_SEC) + { + nsec -= NSEC_PER_SEC; + ++sec; + } + while (nsec < 0) + { + nsec += NSEC_PER_SEC; + --sec; + } + ts->tv_sec = sec; + ts->tv_nsec = nsec; +} + +#endif |