arch/xtensa/variants/s6000/delay.c

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