microsecond_timer_gpt.cpp

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#include "pch.h"
#include "port_microsecond_timer.h"
 
#if EFI_PROD_CODE && HAL_USE_GPT
 
void portSetHardwareSchedulerTimer(efitick_t nowNt, efitick_t setTimeNt) {
    int32_t deltaTimeUs = NT2US((int32_t)setTimeNt - (int32_t)nowNt);
 
    // If already set, reset the timer
    if (GPTDEVICE.state == GPT_ONESHOT) {
        gptStopTimerI(&GPTDEVICE);
    }
 
    if (GPTDEVICE.state != GPT_READY) {
        firmwareError(ObdCode::CUSTOM_HW_TIMER, "HW timer state %d", GPTDEVICE.state);
        return;
    }
 
    // Start the timer
    gptStartOneShotI(&GPTDEVICE, deltaTimeUs);
}
 
static void hwTimerCallback(GPTDriver*) {
    portMicrosecondTimerCallback();
}
 
/*
 * The specific 1MHz frequency is important here since 'setHardwareUsTimer' method takes microsecond parameter
 * For any arbitrary frequency to work we would need an additional layer of conversion.
 */
static constexpr GPTConfig gpt5cfg = { 1000000, /* 1 MHz timer clock.*/
        hwTimerCallback, /* Timer callback.*/
0, 0 };
 
void portInitMicrosecondTimer() {
    gptStart(&GPTDEVICE, &gpt5cfg);
    efiAssertVoid(ObdCode::CUSTOM_ERR_TIMER_STATE, GPTDEVICE.state == GPT_READY, "hw state");
}
 
#endif // EFI_PROD_CODE
 
// This implementation just uses the generic port counter - this usually returns a count of CPU cycles since start
uint32_t getTimeNowLowerNt() {
    return port_rt_get_counter_value();
}