// See LICENSE for license details.
#include <stdio.h>
#include <stdlib.h>
#include "platform.h"
#include <string.h>
#include "encoding.h"
#include <unistd.h>
#include "sifive/devices/clic.h"
#include "clic/clic_driver.h"
#include "sifive/devices/clint.h"

#ifndef _SIFIVE_COREPLEXIP_ARTY_H
#error 'local_interrupts' demo only supported for Core IP Eval Kits
#endif

// Global Variable used to show
// software interrupts.
volatile uint32_t g_debouncing;

// vector table defined in init.c
typedef void (*interrupt_function_ptr_t) (void);
extern interrupt_function_ptr_t localISR[CLIC_NUM_INTERRUPTS]; 
extern void default_handler(void);

//clic data structure
clic_instance_t clic;

const char * instructions_msg = " \
\n\
              SiFive, Inc\n\
 E21 Core IP Eval Kit 'clic_vectored' demo.\n\
 This demo uses buttons 0, 1, and 2 on the\n\
 Arty board to trigger vectored clic interrupts.\n\
\n\
\n";

void print_instructions() {
  write (STDERR_FILENO, instructions_msg, strlen(instructions_msg));
}


//busy wait for the specified time
void wait_ms(uint64_t ms) {
  static const uint64_t ms_tick = RTC_FREQ/1000;
  volatile uint64_t * mtime  = (uint64_t*) (CLINT_CTRL_ADDR + CLINT_MTIME);
  uint64_t then = (ms_tick * ms) + *mtime;
  while(*mtime<then);
}

void button_0_isr(void) __attribute__((interrupt));
void button_0_isr(void) {
  // Toggle Red LED
  printf("Button 0 was pressed. Toggle Red.\n");
  GPIO_REG(GPIO_OUTPUT_VAL) = GPIO_REG(GPIO_OUTPUT_VAL) ^ (0x1 << RED_LED_OFFSET);
  wait_ms(500);
  clic_enable_interrupt(&clic, (LOCALINTIDBASE + LOCAL_INT_BTN_0));
  GPIO_REG(GPIO_OUTPUT_VAL) = GPIO_REG(GPIO_OUTPUT_VAL) ^ (0x1 << RED_LED_OFFSET);
}

void button_0_setup(void) {
  clic_install_handler(&clic, (LOCALINTIDBASE + LOCAL_INT_BTN_0), button_0_isr);
  clic_enable_interrupt(&clic, (LOCALINTIDBASE + LOCAL_INT_BTN_0));
}

void button_1_isr(void) __attribute__((interrupt));
void button_1_isr(void) {
  // Toggle Red LED
  printf("Button 1 was pressed. Toggle Blue.\n");
  GPIO_REG(GPIO_OUTPUT_VAL) = GPIO_REG(GPIO_OUTPUT_VAL) ^ (0x1 << BLUE_LED_OFFSET);
  wait_ms(500);
  clic_enable_interrupt(&clic, (LOCALINTIDBASE + LOCAL_INT_BTN_1));
  GPIO_REG(GPIO_OUTPUT_VAL) = GPIO_REG(GPIO_OUTPUT_VAL) ^ (0x1 << BLUE_LED_OFFSET);
}

void button_1_setup(void) {
  clic_install_handler(&clic, (LOCALINTIDBASE + LOCAL_INT_BTN_1), button_1_isr);
  clic_enable_interrupt(&clic, (LOCALINTIDBASE + LOCAL_INT_BTN_1));
}

void button_2_isr(void) __attribute__((interrupt));
void button_2_isr(void) {
  // Toggle Red LED
  printf("Button 2 was pressed. Toggle Green.\n");
  GPIO_REG(GPIO_OUTPUT_VAL) = GPIO_REG(GPIO_OUTPUT_VAL) ^ (0x1 << GREEN_LED_OFFSET);
  wait_ms(500);
  clic_enable_interrupt(&clic, (LOCALINTIDBASE + LOCAL_INT_BTN_2));
  GPIO_REG(GPIO_OUTPUT_VAL) = GPIO_REG(GPIO_OUTPUT_VAL) ^ (0x1 << GREEN_LED_OFFSET);
}

void button_2_setup(void) {
  clic_install_handler(&clic, (LOCALINTIDBASE + LOCAL_INT_BTN_2), button_2_isr);
  clic_enable_interrupt(&clic, (LOCALINTIDBASE + LOCAL_INT_BTN_2));
}

void config_gpio()  {
  // Configure LEDs as outputs.
  GPIO_REG(GPIO_INPUT_EN)    &= ~((0x1<< RED_LED_OFFSET) | (0x1<< GREEN_LED_OFFSET) | (0x1 << BLUE_LED_OFFSET)) ;
  GPIO_REG(GPIO_OUTPUT_EN)   |=  ((0x1<< RED_LED_OFFSET)| (0x1<< GREEN_LED_OFFSET) | (0x1 << BLUE_LED_OFFSET)) ;
  GPIO_REG(GPIO_OUTPUT_VAL)  &= ((0x1<< RED_LED_OFFSET) | (0x1<< GREEN_LED_OFFSET)|  (0x1 << BLUE_LED_OFFSET)) ;
}

int main(int argc, char **argv)
{
  clear_csr(mstatus, MSTATUS_MIE);
  clear_csr(mie, IRQ_M_SOFT);
  clear_csr(mie, IRQ_M_TIMER);

  //initialize clic registers and vector table
  clic_init(&clic, CLIC_HART0_ADDR, 
            (interrupt_function_ptr_t*)localISR,
            default_handler,
            CLIC_NUM_INTERRUPTS,
            CLIC_NUM_CONFIG_BITS);

  //initialize gpio and buttons.
  //each button registers an interrupt handler
  config_gpio();
  button_0_setup();
  button_1_setup();
  button_2_setup();

  // Enable all global interrupts
  set_csr(mstatus, MSTATUS_MIE);


  print_instructions();
  while(1);

  return 0;

}