Implement RTC Alarm

epicardium/modules/rtc.c

+#include "epicardium.h"
+#include "modules/log.h"
+#include "api/interrupt-sender.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+
 #include "rtc.h"
 
 #include <stdint.h>
 
 uint32_t epic_rtc_get_seconds(void)
 {
-	return RTC_GetSecond();
+	uint32_t sec, subsec;
+
+	/*
+	 * TODO:  Find out what causes the weird behavior of this function.  The
+	 *        time needed for this call seems to depend on the frequency at
+	 *        which it is called.
+	 */
+	while (RTC_GetTime(&sec, &subsec) == E_BUSY) {
+		vTaskDelay(pdMS_TO_TICKS(4));
+	}
+
+	return sec;
+}
+
+void RTC_IRQHandler(void)
+{
+	int flags = RTC_GetFlags();
+
+	if (flags & MXC_F_RTC_CTRL_ALDF) {
+		RTC_ClearFlags(MXC_F_RTC_CTRL_ALDF);
+		/* TODO: Fix interrupt triggering slightly early */
+		api_interrupt_trigger(EPIC_INT_RTC_ALARM);
+	} else {
+		LOG_WARN("rtc", "Unknown IRQ catched!");
+		/* Disable IRQ so it does not retrigger */
+		NVIC_DisableIRQ(RTC_IRQn);
+	}
+}
+
+int epic_rtc_schedule_alarm(uint32_t timestamp)
+{
+	int res;
+
+	NVIC_EnableIRQ(RTC_IRQn);
+
+	while ((res = RTC_SetTimeofdayAlarm(MXC_RTC, timestamp)) == E_BUSY)
+		;
+
+	if (res != E_SUCCESS) {
+		return -EINVAL;
+	}
+
+	return 0;
 }