//See LICENSE for license details.
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>

#include "platform.h"
#include "encoding.h"

extern int main(int argc, char** argv);
extern void trap_entry();

static unsigned long get_cpu_freq()
{
  return 65000000;
}

unsigned long get_timer_freq()
{
  return get_cpu_freq();
}

uint64_t get_timer_value()
{
#if __riscv_xlen == 32
  while (1) {
    uint32_t hi = read_csr(mcycleh);
    uint32_t lo = read_csr(mcycle);
    if (hi == read_csr(mcycleh))
      return ((uint64_t)hi << 32) | lo;
  }
#else
  return read_csr(mcycle);
#endif
}

static void uart_init(size_t baud_rate)
{
  GPIO_REG(GPIO_IOF_SEL) &= ~IOF0_UART0_MASK;
  GPIO_REG(GPIO_IOF_EN) |= IOF0_UART0_MASK;
  UART0_REG(UART_REG_DIV) = get_cpu_freq() / baud_rate - 1;
  UART0_REG(UART_REG_TXCTRL) |= UART_TXEN;
}


#ifdef USE_PLIC
extern void handle_m_ext_interrupt();
#endif

#ifdef USE_M_TIME
extern void handle_m_time_interrupt();
#endif

uintptr_t handle_trap(uintptr_t mcause, uintptr_t epc)
{
  if (0){
#ifdef USE_PLIC
    // External Machine-Level interrupt from PLIC
  } else if ((mcause & MCAUSE_INT) && ((mcause & MCAUSE_CAUSE) == IRQ_M_EXT)) {
    handle_m_ext_interrupt();
#endif
#ifdef USE_M_TIME
    // External Machine-Level interrupt from PLIC
  } else if ((mcause & MCAUSE_INT) && ((mcause & MCAUSE_CAUSE) == IRQ_M_TIMER)){
    handle_m_time_interrupt();
#endif
  }
  else {
    write(1, "Unhandled Trap:\n", 16);
    _exit(1 + mcause);
  }
  return epc;
}

void _init()
{
  #ifndef NO_INIT
  uart_init(115200);

  printf("core freq at %d Hz\n", get_cpu_freq());

  write_csr(mtvec, &trap_entry);
  #endif
}

void _fini()
{
}