#include "project.h"


static uint8_t dma_buf[DMA_BUF_SZ];
uint8_t vram_2[DMA_BUF_SZ];

static int dma_in_progress = 0;
static int refresh_enabled = 0;
static uint32_t refresh_wdt = 0;
static int oled_sad = 0;


static void
start_dma (void)
{
  uint8_t cmds[] = {
    SSD1306_SET_PAGE_ADDR, 0, 0xff,
    SSD1306_SET_COLUMN_ADDR, 0, SSD1306_WIDTH - 1
  };

  if (dma_in_progress)
    return;


  memcpy (dma_buf, vram_2, DMA_BUF_SZ);

  if (ssd1306_cmds (I2C2, cmds, sizeof (cmds), 0)) {
    oled_sad++;
    return;
  }

  if (i2cp_start_transaction (I2C2, SSD1306_I2C_ADDRESS, I2C_WRITE)) {
    oled_sad++;
    return;
  }

  refresh_wdt = 0;
  dma_in_progress = 1;

  i2cp2_start_dma (dma_buf, DMA_BUF_SZ);
}



void
dma1_channel4_isr (void)
{
  if (dma_in_progress) {
    i2cp2_stop_dma();

    i2cp_stop (I2C2);
    dma_in_progress = 0;
  }

  if (refresh_enabled)
    start_dma();
}

void
oled2_ticker (void)
{
  if (!refresh_enabled)
    return;

  refresh_wdt++;

  if ((refresh_wdt < MS_TO_TICKS (1000)) && (!oled_sad))
    return;

  refresh_wdt = 0;

  /*No refresh for 1s, restart everything */

  i2cp2_stop_dma();
  i2cp_stop (I2C2);
  dma_in_progress = 0;

  if (oled_sad) {
    oled_sad = 0;
    i2cp2_reset_sm();
  }

  start_dma();

}

void
oled2_enable_refresh (void)
{
  refresh_enabled = 1;
  start_dma();
}


void
oled2_disable_refresh (void)
{
  refresh_enabled = 0;

  while (dma_in_progress);
}



void
oled2_init (void)
{
  oled_reset (I2C2);

  delay_us (100);

  oled_generate_stream (vram_2);

  nvic_enable_irq (NVIC_DMA1_CHANNEL4_IRQ);
  oled2_enable_refresh();
}


void
oled2_shutdown (void)
{
  oled2_disable_refresh();
  oled_off (I2C2);
}