arch/xtensa/variants/s6000/delay.c

   1 #include <asm/delay.h>
   2 #include <asm/timex.h>
   3 #include <asm/io.h>
   4 #include <variant/hardware.h>
   5
   6 #define LOOPS 10
   7 void platform_calibrate_ccount(void)
   8 {
   9         u32 uninitialized_var(a);
  10         u32 uninitialized_var(u);
  11         u32 b;
  12         u32 tstamp = S6_REG_GREG1 + S6_GREG1_GLOBAL_TIMER;
  13         int i = LOOPS+1;
  14         do {
  15                 u32 t = u;
  16                 asm volatile(
  17                 "1:     l32i %0, %2, 0 ;"
  18                 "       beq %0, %1, 1b ;"
  19                 : "=&a"(u) : "a"(t), "a"(tstamp));
  20                 b = xtensa_get_ccount();
  21                 if (i == LOOPS)
  22                         a = b;
  23         } while (--i >= 0);
  24         b -= a;
  25         nsec_per_ccount = (LOOPS * 10000) / b;
  26         ccount_per_jiffy = b * (100000UL / (LOOPS * HZ));
  27 }