neorv32/sw/lib/source/neorv32_mtime.c

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2024-02-24 08:25:27 +00:00
// #################################################################################################
// # << NEORV32: neorv32_mtime.c - Machine System Timer (MTIME) HW Driver >> #
// # ********************************************************************************************* #
// # BSD 3-Clause License #
// # #
// # Copyright (c) 2022, Stephan Nolting. All rights reserved. #
// # #
// # Redistribution and use in source and binary forms, with or without modification, are #
// # permitted provided that the following conditions are met: #
// # #
// # 1. Redistributions of source code must retain the above copyright notice, this list of #
// # conditions and the following disclaimer. #
// # #
// # 2. Redistributions in binary form must reproduce the above copyright notice, this list of #
// # conditions and the following disclaimer in the documentation and/or other materials #
// # provided with the distribution. #
// # #
// # 3. Neither the name of the copyright holder nor the names of its contributors may be used to #
// # endorse or promote products derived from this software without specific prior written #
// # permission. #
// # #
// # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS #
// # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF #
// # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE #
// # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, #
// # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE #
// # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED #
// # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING #
// # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED #
// # OF THE POSSIBILITY OF SUCH DAMAGE. #
// # ********************************************************************************************* #
// # The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting #
// #################################################################################################
/**********************************************************************//**
* @file neorv32_mtime.c
* @brief Machine System Timer (MTIME) HW driver source file.
*
* @note These functions should only be used if the MTIME unit was synthesized (IO_MTIME_EN = true).
**************************************************************************/
#include "neorv32.h"
#include "neorv32_mtime.h"
/**********************************************************************//**
* Check if MTIME unit was synthesized.
*
* @return 0 if MTIME was not synthesized, 1 if MTIME is available.
**************************************************************************/
int neorv32_mtime_available(void) {
if (NEORV32_SYSINFO->SOC & (1 << SYSINFO_SOC_IO_MTIME)) {
return 1;
}
else {
return 0;
}
}
/**********************************************************************//**
* Set current system time.
*
* @note The MTIME timer increments with the primary processor clock.
*
* @param[in] time New system time (uint64_t)
**************************************************************************/
void neorv32_mtime_set_time(uint64_t time) {
union {
uint64_t uint64;
uint32_t uint32[sizeof(uint64_t)/sizeof(uint32_t)];
} cycles;
cycles.uint64 = time;
NEORV32_MTIME->TIME_LO = 0;
NEORV32_MTIME->TIME_HI = cycles.uint32[1];
NEORV32_MTIME->TIME_LO = cycles.uint32[0];
asm volatile("nop"); // delay due to write buffer
}
/**********************************************************************//**
* Get current system time.
*
* @note The MTIME timer increments with the primary processor clock.
*
* @return Current system time (uint64_t)
**************************************************************************/
uint64_t neorv32_mtime_get_time(void) {
union {
uint64_t uint64;
uint32_t uint32[sizeof(uint64_t)/sizeof(uint32_t)];
} cycles;
uint32_t tmp1, tmp2, tmp3;
while(1) {
tmp1 = NEORV32_MTIME->TIME_HI;
tmp2 = NEORV32_MTIME->TIME_LO;
tmp3 = NEORV32_MTIME->TIME_HI;
if (tmp1 == tmp3) {
break;
}
}
cycles.uint32[0] = tmp2;
cycles.uint32[1] = tmp3;
return cycles.uint64;
}
/**********************************************************************//**
* Set compare time register (MTIMECMP) for generating interrupts.
*
* @note The interrupt is triggered when MTIME >= MTIMECMP.
* @note Global interrupts and the timer interrupt source have to be enabled .
*
* @param[in] timecmp System time for interrupt (uint64_t)
**************************************************************************/
void neorv32_mtime_set_timecmp(uint64_t timecmp) {
union {
uint64_t uint64;
uint32_t uint32[sizeof(uint64_t)/sizeof(uint32_t)];
} cycles;
cycles.uint64 = timecmp;
NEORV32_MTIME->TIMECMP_LO = -1; // prevent MTIMECMP from temporarily becoming smaller than the lesser of the old and new values
NEORV32_MTIME->TIMECMP_HI = cycles.uint32[1];
NEORV32_MTIME->TIMECMP_LO = cycles.uint32[0];
asm volatile("nop"); // delay due to write buffer
}
/**********************************************************************//**
* Get compare time register (MTIMECMP).
*
* @return Current MTIMECMP value.
**************************************************************************/
uint64_t neorv32_mtime_get_timecmp(void) {
union {
uint64_t uint64;
uint32_t uint32[sizeof(uint64_t)/sizeof(uint32_t)];
} cycles;
cycles.uint32[0] = NEORV32_MTIME->TIMECMP_LO;
cycles.uint32[1] = NEORV32_MTIME->TIMECMP_HI;
return cycles.uint64;
}