diff options
Diffstat (limited to 'util/flashrom/udelay.c')
-rw-r--r-- | util/flashrom/udelay.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/util/flashrom/udelay.c b/util/flashrom/udelay.c new file mode 100644 index 0000000000..30b8dde261 --- /dev/null +++ b/util/flashrom/udelay.c @@ -0,0 +1,37 @@ +#include <sys/time.h> +#include <stdio.h> + +// count to a billion. Time it. If it's < 1 sec, count to 10B, etc. +unsigned long micro = 1; + +void myusec_delay(int time) +{ + volatile unsigned long i; + for (i = 0; i < time * micro; i++); +} + +void myusec_calibrate_delay() +{ + int count = 1000; + unsigned long timeusec; + struct timeval start, end; + int ok = 0; + + printf("Setting up microsecond timing loop\n"); + while (!ok) { + gettimeofday(&start, 0); + myusec_delay(count); + gettimeofday(&end, 0); + timeusec = 1000000 * (end.tv_sec - start.tv_sec) + + (end.tv_usec - start.tv_usec); + count *= 2; + if (timeusec < 1000000 / 4) + continue; + ok = 1; + } + + // compute one microsecond. That will be count / time + micro = count / timeusec; + + fprintf(stderr, "%ldM loops per second\n", (unsigned long) micro); +} |