2b793e4945
Make the frclock functions similar to the tsc utility functions. This way, we can call frclock functions from the framebuffer driver which will use frclock on ARM and tsc on X86. Also, frclock_64_to_micros computed seconds, not microseconds Change-Id: I6718ae0fb7db050794f6f032205923e1a32dc1ac
119 lines
2.3 KiB
C
119 lines
2.3 KiB
C
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#include <stdio.h>
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#include <time.h>
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#include <sys/times.h>
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#include <sys/types.h>
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#include <minix/u64.h>
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#include <minix/config.h>
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#include <minix/const.h>
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#include <minix/minlib.h>
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#include <machine/archtypes.h>
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#include "sysutil.h"
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#ifndef CONFIG_MAX_CPUS
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#define CONFIG_MAX_CPUS 1
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#endif
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#define MICROHZ 1000000 /* number of micros per second */
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#define MICROSPERTICK(h) (MICROHZ/(h)) /* number of micros per HZ tick */
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#define CALIBRATE \
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if(!calibrated) { \
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int r; \
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if((r=tsc_calibrate()) != OK) \
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panic("calibrate failed: %d", r); \
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}
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static u32_t calib_mhz, Hz = 0;
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static int calibrated = 0;
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int
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tsc_calibrate(void)
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{
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struct cpu_info cpu_info[CONFIG_MAX_CPUS];
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/* Get HZ. */
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Hz = sys_hz();
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/* Obtain CPU frequency from kernel */
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if (sys_getcpuinfo(&cpu_info)) {
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printf("tsc_calibrate: cannot get cpu info\n");
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return -1;
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}
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/* For now, use the frequency of the first CPU; everything here will
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* break down in case we get scheduled on multiple CPUs with different
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* frequencies regardless
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*/
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calib_mhz = cpu_info[0].freq;
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calibrated = 1;
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return OK;
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}
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int
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micro_delay(u32_t micros)
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{
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u64_t now, end;
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/* Start of delay. */
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read_tsc_64(&now);
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CALIBRATE;
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/* We have to know when to end the delay. */
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end = add64(now, mul64u(micros, calib_mhz));
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/* If we have to wait for at least one HZ tick, use the regular
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* tickdelay first. Round downwards on purpose, so the average
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* half-tick we wait short (depending on where in the current tick
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* we call tickdelay). We can correct for both overhead of tickdelay
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* itself and the short wait in the busywait later.
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*/
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if(micros >= MICROSPERTICK(Hz))
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tickdelay(micros*Hz/MICROHZ);
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/* Wait (the rest) of the delay time using busywait. */
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while(cmp64(now, end) < 0)
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read_tsc_64(&now);
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return OK;
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}
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u32_t tsc_64_to_micros(u64_t tsc)
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{
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u64_t tmp;
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CALIBRATE;
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tmp = div64u64(tsc, calib_mhz);
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if (ex64hi(tmp)) {
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printf("tsc_64_to_micros: more than 2^32ms\n");
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return ~0UL;
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} else {
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return ex64lo(tmp);
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}
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}
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u32_t tsc_to_micros(u32_t low, u32_t high)
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{
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return tsc_64_to_micros(make64(low, high));
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}
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u32_t tsc_get_khz(void)
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{
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CALIBRATE;
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return calib_mhz * 1000;
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}
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#define frclock_64_to_micros tsc_64_to_micros
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#define read_frclock_64 read_tsc_64
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u64_t delta_frclock_64(u64_t base, u64_t cur)
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{
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return cur - base;
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}
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