91 lines
2.1 KiB
C

/*
* This file is part of open_agb_firm
* Copyright (C) 2023 derrek, profi200
*
* 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 <http://www.gnu.org/licenses/>.
*/
#include "types.h"
#include "arm9/drivers/timer.h"
#include "arm9/drivers/interrupt.h"
#include "arm.h"
// For TIMER_sleepMs().
static au32 g_overflows;
static void timerSleepHandler(UNUSED u32 id);
void TIMER_init(void)
{
for(u32 i = 0; i < 4; i++)
{
getTimerRegs(i)->cnt = 0;
}
IRQ_registerIsr(IRQ_TIMER_3, timerSleepHandler);
}
void TIMER_start(const u8 tmr, const u16 ticks, const u8 params)
{
Timer *const timer = getTimerRegs(tmr);
timer->val = ticks;
timer->cnt = TIMER_EN | params;
}
u16 TIMER_getTicks(const u8 tmr)
{
return getTimerRegs(tmr)->val;
}
u16 TIMER_stop(const u8 tmr)
{
Timer *const timer = getTimerRegs(tmr);
timer->cnt = 0;
return timer->val;
}
void TIMER_sleepMs(const u32 ms)
{
Timer *const timer = getTimerRegs(3);
timer->val = TIMER_FREQ_64(1000);
// With LTO enabled gcc may move the write to g_overflows after
// the write to TIMER_CNT.
// We have to use signal fence to avoid calls to the atomic lib.
atomic_store_explicit(&g_overflows, ms, memory_order_relaxed);
atomic_signal_fence(memory_order_release);
timer->cnt = TIMER_EN | TIMER_IRQ_EN | TIMER_PRESC_64;
do
{
__wfi();
} while(timer->cnt & TIMER_EN);
}
static void timerSleepHandler(UNUSED u32 id)
{
u32 tmp = atomic_load_explicit(&g_overflows, memory_order_relaxed);
if(--tmp == 0)
{
getTimerRegs(3)->cnt = 0;
return;
}
atomic_store_explicit(&g_overflows, tmp, memory_order_relaxed);
}