Firmware2/Marlin/src/HAL/shared/Delay.h
2020-07-22 22:20:14 -05:00

162 lines
4.4 KiB
C

/**
* Marlin 3D Printer Firmware
* Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
#pragma once
/**
* Busy wait delay cycles routines:
*
* DELAY_CYCLES(count): Delay execution in cycles
* DELAY_NS(count): Delay execution in nanoseconds
* DELAY_US(count): Delay execution in microseconds
*/
#include "../../core/macros.h"
#if defined(__arm__) || defined(__thumb__)
#if __CORTEX_M == 7
// Cortex-M3 through M7 can use the cycle counter of the DWT unit
// https://www.anthonyvh.com/2017/05/18/cortex_m-cycle_counter/
FORCE_INLINE static void enableCycleCounter() {
CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
#if __CORTEX_M == 7
DWT->LAR = 0xC5ACCE55; // Unlock DWT on the M7
#endif
DWT->CYCCNT = 0;
DWT->CTRL |= DWT_CTRL_CYCCNTENA_Msk;
}
FORCE_INLINE volatile uint32_t getCycleCount() { return DWT->CYCCNT; }
FORCE_INLINE static void DELAY_CYCLES(const uint32_t x) {
const uint32_t endCycles = getCycleCount() + x;
while (PENDING(getCycleCount(), endCycles)) {}
}
#else
// https://blueprints.launchpad.net/gcc-arm-embedded/+spec/delay-cycles
#define nop() __asm__ __volatile__("nop;\n\t":::)
FORCE_INLINE static void __delay_4cycles(uint32_t cy) { // +1 cycle
#if ARCH_PIPELINE_RELOAD_CYCLES < 2
#define EXTRA_NOP_CYCLES A("nop")
#else
#define EXTRA_NOP_CYCLES ""
#endif
__asm__ __volatile__(
A(".syntax unified") // is to prevent CM0,CM1 non-unified syntax
L("1")
A("subs %[cnt],#1")
EXTRA_NOP_CYCLES
A("bne 1b")
: [cnt]"+r"(cy) // output: +r means input+output
: // input:
: "cc" // clobbers:
);
}
// Delay in cycles
FORCE_INLINE static void DELAY_CYCLES(uint32_t x) {
if (__builtin_constant_p(x)) {
#define MAXNOPS 4
if (x <= (MAXNOPS)) {
switch (x) { case 4: nop(); case 3: nop(); case 2: nop(); case 1: nop(); }
}
else { // because of +1 cycle inside delay_4cycles
const uint32_t rem = (x - 1) % (MAXNOPS);
switch (rem) { case 3: nop(); case 2: nop(); case 1: nop(); }
if ((x = (x - 1) / (MAXNOPS)))
__delay_4cycles(x); // if need more then 4 nop loop is more optimal
}
#undef MAXNOPS
}
else if ((x >>= 2))
__delay_4cycles(x);
}
#undef nop
#endif
#elif defined(__AVR__)
#define nop() __asm__ __volatile__("nop;\n\t":::)
FORCE_INLINE static void __delay_4cycles(uint8_t cy) {
__asm__ __volatile__(
L("1")
A("dec %[cnt]")
A("nop")
A("brne 1b")
: [cnt] "+r"(cy) // output: +r means input+output
: // input:
: "cc" // clobbers:
);
}
// Delay in cycles
FORCE_INLINE static void DELAY_CYCLES(uint16_t x) {
if (__builtin_constant_p(x)) {
#define MAXNOPS 4
if (x <= (MAXNOPS)) {
switch (x) { case 4: nop(); case 3: nop(); case 2: nop(); case 1: nop(); }
}
else {
const uint32_t rem = (x) % (MAXNOPS);
switch (rem) { case 3: nop(); case 2: nop(); case 1: nop(); }
if ((x = (x) / (MAXNOPS)))
__delay_4cycles(x); // if need more then 4 nop loop is more optimal
}
#undef MAXNOPS
}
else if ((x >>= 2))
__delay_4cycles(x);
}
#undef nop
#elif defined(__PLAT_LINUX__) || defined(ESP32)
// specified inside platform
#else
#error "Unsupported MCU architecture"
#endif
// Delay in nanoseconds
#define DELAY_NS(x) DELAY_CYCLES( (x) * (F_CPU / 1000000UL) / 1000UL )
// Delay in microseconds
#define DELAY_US(x) DELAY_CYCLES( (x) * (F_CPU / 1000000UL) )