f-stack/dpdk/lib/eal/riscv/rte_cycles.c

78 lines
1.7 KiB
C

/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2015 Cavium, Inc
* Copyright(c) 2022 StarFive
* Copyright(c) 2022 SiFive
* Copyright(c) 2022 Semihalf
*/
#include <stdio.h>
#include "eal_private.h"
#include "rte_byteorder.h"
#include "rte_cycles.h"
#include "rte_log.h"
/** Read generic counter frequency */
static uint64_t
__rte_riscv_timefrq(void)
{
#define TIMEBASE_FREQ_SIZE 8
if (RTE_RISCV_TIME_FREQ > 0)
return RTE_RISCV_TIME_FREQ;
uint8_t buf[TIMEBASE_FREQ_SIZE];
ssize_t cnt;
FILE *file;
file = fopen("/proc/device-tree/cpus/timebase-frequency", "rb");
if (!file)
goto fail;
cnt = fread(buf, 1, TIMEBASE_FREQ_SIZE, file);
fclose(file);
switch (cnt) {
case 8:
return rte_be_to_cpu_64(*(uint64_t *)buf);
case 4:
return rte_be_to_cpu_32(*(uint32_t *)buf);
default:
break;
}
fail:
RTE_LOG(WARNING, EAL, "Unable to read timebase-frequency from FDT.\n");
return 0;
}
uint64_t
get_tsc_freq_arch(void)
{
RTE_LOG(NOTICE, EAL, "TSC using RISC-V %s.\n",
RTE_RISCV_RDTSC_USE_HPM ? "rdcycle" : "rdtime");
if (!RTE_RISCV_RDTSC_USE_HPM)
return __rte_riscv_timefrq();
#define CYC_PER_1MHZ 1E6
/*
* Use real time clock to estimate current cycle frequency
*/
uint64_t ticks, frq;
uint64_t start_ticks, cur_ticks;
uint64_t start_cycle, end_cycle;
/* Do not proceed unless clock frequency can be obtained. */
frq = __rte_riscv_timefrq();
if (!frq)
return 0;
/* Number of ticks for 1/10 second */
ticks = frq / 10;
start_ticks = __rte_riscv_rdtime_precise();
start_cycle = rte_rdtsc_precise();
do {
cur_ticks = __rte_riscv_rdtime();
} while ((cur_ticks - start_ticks) < ticks);
end_cycle = rte_rdtsc_precise();
/* Adjust the cycles to next 1Mhz */
return RTE_ALIGN_MUL_CEIL((end_cycle - start_cycle) * 10, CYC_PER_1MHZ);
}