1/* 2 * Copyright 2017, Data61 3 * Commonwealth Scientific and Industrial Research Organisation (CSIRO) 4 * ABN 41 687 119 230. 5 * 6 * This software may be distributed and modified according to the terms of 7 * the BSD 2-Clause license. Note that NO WARRANTY is provided. 8 * See "LICENSE_BSD2.txt" for details. 9 * 10 * @TAG(DATA61_BSD) 11 */ 12 13#include <autoconf.h> 14#include <platsupport/gen_config.h> 15#include <platsupport/arch/tsc.h> 16#include <platsupport/delay.h> 17#include <stdint.h> 18#include <stdio.h> 19 20#define DEFAULT_CPUFREQ 1500000000UL 21 22static unsigned long cpufreq_hint = DEFAULT_CPUFREQ; 23#define CYCLES_PER_US(cpufreq) (cpufreq / 1000000) 24 25static void 26ps_do_cycle_delay(uint64_t cycles) 27{ 28 uint64_t end = rdtsc_pure() + cycles; 29 30 while (1) { 31 if (end <= rdtsc_pure()) { 32 break; 33 } 34 } 35} 36 37void 38ps_udelay(unsigned long us) 39{ 40 ps_do_cycle_delay((uint64_t)us * CYCLES_PER_US(cpufreq_hint)); 41} 42 43void 44ps_cpufreq_hint(unsigned long hz) 45{ 46 if (hz == 0) { 47 ZF_LOGW("%s:%d - Invalid CPU frequency for delay loop, use the default\n", 48 __FILE__, __LINE__); 49 hz = DEFAULT_CPUFREQ; 50 } 51 52 cpufreq_hint = hz; 53} 54