qmk-firmware/keyboards/handwired/onekey/keymaps/chibios_waiting_test/keymap.c
Stefan Kerkmann 3f5dc47296
[Core] Use polled waiting on ChibiOS platforms that support it (#17607)
* Use polled waiting on platforms that support it

Due to context switching overhead waiting a very short amount of time on
a sleeping thread is often not accurate and in fact not usable for timing
critical usage i.e. in a driver. Thus we use polled waiting for ranges
in the us range on platforms that support it instead. The fallback is
the thread sleeping mechanism.

This includes:

* ARM platforms with CYCCNT register (ARMv7, ARMv8) this is
  incremented at CPU clock frequency
* GD32VF103 RISC-V port with CSR_MCYCLE register this is incremented at
  CPU clock frequency
* RP2040 ARMv6 port which uses the integrated timer peripheral which is
  incremented with a fixed 1MHz frequency

* Use wait_us() instead of chSysPolledDelayX

...as it is powered by busy waiting now.

* Add chibios waiting methods test bench
2022-07-11 15:17:05 +02:00

48 lines
1.5 KiB
C

// Copyright 2022 Stefan Kerkmann
// SPDX-License-Identifier: GPL-2.0-or-later
#include QMK_KEYBOARD_H
const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {LAYOUT_ortho_1x1(KC_A)};
#if defined(__AVR__)
# pragma message "AVR uses polled waiting by default, running theses tests will not show any difference"
static inline void chThdSleepMicroseconds(uint32_t us) {
wait_us(us);
}
#endif
void keyboard_post_init_user(void) {
setPinOutput(QMK_WAITING_TEST_BUSY_PIN);
setPinOutput(QMK_WAITING_TEST_YIELD_PIN);
}
static inline void wait_us_polling_with_strobe(uint32_t us) {
writePinHigh(QMK_WAITING_TEST_BUSY_PIN);
wait_us(us);
writePinLow(QMK_WAITING_TEST_BUSY_PIN);
}
static inline void wait_us_yield_with_strobe(uint32_t us) {
writePinHigh(QMK_WAITING_TEST_YIELD_PIN);
chThdSleepMicroseconds(us);
writePinLow(QMK_WAITING_TEST_YIELD_PIN);
}
static const uint32_t waiting_values[] = {0, 1, 5, 10, 25, 50, 100, 150, 200, 500, 1000};
void housekeeping_task_user(void) {
static uint32_t last_bench = 0;
if (timer_elapsed32(last_bench) > 500) {
for (int i = 0; i < (sizeof(waiting_values) / sizeof(waiting_values[0])); i++) {
wait_us_polling_with_strobe(waiting_values[i]);
wait_us(10);
}
for (int i = 0; i < (sizeof(waiting_values) / sizeof(waiting_values[0])); i++) {
wait_us_yield_with_strobe(waiting_values[i]);
wait_us(10);
}
last_bench = timer_read32();
}
}