arch/arm/cpu/armv8/generic_timer.c

   1 /*
   2  * (C) Copyright 2013
   3  * David Feng <fenghua@phytium.com.cn>
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <command.h>
  10 #include <asm/system.h>
  11
  12 /*
  13  * Generic timer implementation of get_tbclk()
  14  */
  15 unsigned long get_tbclk(void)
  16 {
  17         unsigned long cntfrq;
  18         asm volatile("mrs %0, cntfrq_el0" : "=r" (cntfrq));
  19         return cntfrq;
  20 }
  21
  22 /*
  23  * Generic timer implementation of timer_read_counter()
  24  */
  25 unsigned long timer_read_counter(void)
  26 {
  27         unsigned long cntpct;
  28 #ifdef CONFIG_SYS_FSL_ERRATUM_A008585
  29         /* This erratum number needs to be confirmed to match ARM document */
  30         unsigned long temp;
  31 #endif
  32         isb();
  33         asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct));
  34 #ifdef CONFIG_SYS_FSL_ERRATUM_A008585
  35         asm volatile("mrs %0, cntpct_el0" : "=r" (temp));
  36         while (temp != cntpct) {
  37                 asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct));
  38                 asm volatile("mrs %0, cntpct_el0" : "=r" (temp));
  39         }
  40 #endif
  41         return cntpct;
  42 }
  43
  44 unsigned long usec2ticks(unsigned long usec)
  45 {
  46         ulong ticks;
  47         if (usec < 1000)
  48                 ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
  49         else
  50                 ticks = ((usec / 10) * (get_tbclk() / 100000));
  51
  52         return ticks;
  53 }