#include <sys/types.h>
#include <sys/mman.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <assert.h>
#include <fcntl.h>

#include "voodoo2.h"

struct name_int {
  const char * name;
  uint32_t value;
};

void print_registers(struct voodoo2_reg * reg)
{
  const struct name_int registers[] = {
    {"status", reg->status},
    {"fbiInit0", reg->fbiInit0},
    {"fbiInit1", reg->fbiInit1},
    {"fbiInit2", reg->fbiInit2},
    {"fbiInit3", reg->fbiInit3},
    {"fbiInit4", reg->fbiInit4},
    {"fbiInit5", reg->fbiInit5},
    {"fbiInit6", reg->fbiInit6},
    {"fbiInit7", reg->fbiInit7},
    //
    {"backPorch", reg->backPorch},
    {"videoDimensions", reg->videoDimensions},
    {"hSync", reg->hSync},
    {"vSync", reg->vSync},
  };

  for (int i = 0; i < (sizeof (registers)) / (sizeof (registers[0])); i++) {
    printf("%s %08x\n", registers[i].name, registers[i].value);
  }
}

static inline void wait_graphics_busy(voodoo2_reg * voodoo2)
{
  int cnt = 0;
  for (int i = 0; i < 4096; i++) {
    if (voodoo2->status & STATUS__GRAPHICS_BUSY) {
      cnt += 1;
    } else {
      cnt = 0;
    }
    if (cnt >= 3)
      return;
  }

  assert(!"busy wait timeout");
}

static inline void dac_data_read(voodoo2_reg * voodoo2,
                                 int data,
                                 int rs)
{
  voodoo2->dacData
    = DACDATA__WRITE_DATA(data)
    | DACDATA__ADDRESS_2_0(rs >> 0)
    | DACDATA__READ_COMMAND
    | DACDATA__ADDRESS_4_3(rs >> 3)
    ;
}

static inline void dac_data_write(voodoo2_reg * voodoo2,
                                  int data,
                                  int rs)
{
  voodoo2->dacData
    = DACDATA__WRITE_DATA(data)
    | DACDATA__ADDRESS_2_0(rs >> 0)
    | DACDATA__ADDRESS_4_3(rs >> 3)
    ;
}

static inline void dac_write_pll_8(voodoo2_reg * voodoo2,
                                   int address,
                                   int parameter_m)
{
  dac_data_write(voodoo2, address, DAC__RS__PLL_ADDRESS_WRITE, 0);
  wait_graphics_busy(voodoo2);

  dac_data_write(voodoo2, parameter_m, DAC__RS__PLL_PARAMETER, 0);
  wait_graphics_busy(voodoo2);
}

static inline void dac_write_pll_16(voodoo2_reg * voodoo2,
                                    int address,
                                    int parameter_m,
                                    int parameter_n)
{
  dac_data_write(voodoo2, address, DAC__RS__PLL_ADDRESS_WRITE, 0);
  wait_graphics_busy(voodoo2);

  dac_data_write(voodoo2, parameter_m, DAC__RS__PLL_PARAMETER, 0);
  wait_graphics_busy(voodoo2);

  dac_data_write(voodoo2, parameter_n, DAC__RS__PLL_PARAMETER, 0);
  wait_graphics_busy(voodoo2);
}

typedef struct mn {
  uint8_t m;
  uint8_t n;
} mn_t;

static inline struct mn_t dac_read_16(voodoo2_reg * voodoo,
                                      int address)
{
  dac_data_write(base, address, DAC__RS__PLL_ADDRESS_READ);
  wait_graphics_busy(base);

  dac_data_read(base, 0, DAC__RS__PLL_PARAMETER);
  wait_graphics_busy(base);
  int m = voodoo2->fbiInit2 & 0xff;

  dac_data_read(base, 0, DAC__RS__PLL_PARAMETER);
  wait_graphics_busy(base);
  int n = voodoo2->fbiInit2 & 0xff;

  return (struct m_n){ m, n };
}

int main()
{
  const char * config = "/sys/bus/pci/devices/0000:02:0a.0/config";
  int fd = open(config, O_RDWR | O_SYNC);
  assert(fd >= 0);

  const char * filename = "/sys/bus/pci/devices/0000:02:0a.0/resource0";

  int fd = open(filename, O_RDWR | O_SYNC);
  assert(fd >= 0);

  uint32_t map_size = 0x4000;

  off_t target_base = 0;
  void * map_base = mmap(0, map_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, target_base);
  assert(map_base != MAP_FAILED);

  struct voodoo2_reg * reg = (struct voodoo2_reg *)map_base;
  print_registers(reg);

  close(fd);
}