#include <assert.h>
#include <rtc.h>
#include <stdint.h>

#define VIRT_RTC_BASE 0x0101000UL
#define VIRT_RTC_SIZE 0x1000

#define RTC_TIME_LOW   0x00
#define RTC_TIME_HIGH  0x04
#define RTC_ALARM_LOW  0x08
#define RTC_ALARM_HIGH 0x0c

#define RTC_ALARM_STATUS 0x18
#define RTC_CLEAR_ALARM  0x14

#define RTC_IRQ_ENABLED 0x10
#define RTC_IRQ_CLEAR   0x1c

#define REG32(addr)      (*((volatile uint32_t *)(addr)))
#define REG64(addr)      (*((volatile uint64_t *)(addr)))
#define GF_REG32(offset) (REG32(VIRT_RTC_BASE + offset))
#define GF_REG64(offset) (REG64(VIRT_RTC_BASE + offset))

/* Read the current time of the RTC */
uint64_t rtc_time_read(void) {
    uint32_t low = GF_REG32(RTC_TIME_LOW); // mmio_read32(VIRT_RTC_BASE + RTC_TIME_LOW);
    uint32_t high = GF_REG32(RTC_TIME_HIGH);
    return ((uint64_t)high << 32) | low;
}

/* Set the time of the RTC */
void rtc_time_set(uint64_t ns) {
    GF_REG32(RTC_TIME_HIGH) = ns >> 32;
    GF_REG32(RTC_TIME_LOW) = ns & 0xFFFFFFFF;
}

/* Set the alarm. this will automatically enable it. */
void rtc_alarm_set(uint64_t ns) {
    /* Order matters here, low write starts the alarm */
    GF_REG32(RTC_ALARM_HIGH) = ns >> 32;
    GF_REG32(RTC_ALARM_LOW) = ns & 0xFFFFFFFF;
}

uint64_t rtc_alarm_read(void) {
    uint32_t low = GF_REG32(RTC_ALARM_LOW);
    uint32_t high = GF_REG32(RTC_ALARM_HIGH);
    return ((uint64_t)high << 32) | low;
}

uint32_t rtc_alarm_status(void) {
    return GF_REG32(RTC_ALARM_STATUS) & 0x1;
}

void rtc_alarm_clear(void) {
    GF_REG32(RTC_CLEAR_ALARM) = 1;
}

void rtc_irq_clear(void) {
    GF_REG32(RTC_IRQ_CLEAR) = 1;
}

uint32_t rtc_irq_enabled(void) {
    return GF_REG32(RTC_IRQ_ENABLED) & 0x1;
}