#include "bsp/pmod_spi.h"

#include "bsp/mmio.h"
#include "bsp/soc.h"

#define PMOD_SPI_CTRL  (BSP_PMOD_SPI_BASE + 0x00u)
#define PMOD_SPI_TX    (BSP_PMOD_SPI_BASE + 0x04u)
#define PMOD_SPI_RX    (BSP_PMOD_SPI_BASE + 0x08u)
#define PMOD_SPI_READY (BSP_PMOD_SPI_BASE + 0x0cu)

#define PMOD_SPI_CTRL_BUSY 0x1u
#define PMOD_SPI_CTRL_CSN  0x2u
#define PMOD_SPI_CTRL_QUAD 0x4u

static uint32_t pmod_spi_ctrl_shadow = PMOD_SPI_CTRL_CSN;

static void pmod_spi_wait_ready(void)
{
  while ((bsp_read32(PMOD_SPI_READY) & 1u) == 0u) {
  }
  while ((bsp_read32(PMOD_SPI_CTRL) & PMOD_SPI_CTRL_BUSY) != 0u) {
  }
}

static void pmod_spi_write_ctrl(uint32_t ctrl)
{
  pmod_spi_wait_ready();
  pmod_spi_ctrl_shadow = ctrl & (PMOD_SPI_CTRL_CSN | PMOD_SPI_CTRL_QUAD);
  bsp_write32(PMOD_SPI_CTRL, pmod_spi_ctrl_shadow);
}

void bsp_pmod_spi_init(void)
{
  pmod_spi_write_ctrl(PMOD_SPI_CTRL_CSN);
}

void bsp_pmod_spi_set_mode(bsp_pmod_spi_mode_t mode)
{
  uint32_t ctrl = pmod_spi_ctrl_shadow & ~PMOD_SPI_CTRL_QUAD;
  if (mode == BSP_PMOD_SPI_MODE_QUAD) {
    ctrl |= PMOD_SPI_CTRL_QUAD;
  }
  pmod_spi_write_ctrl(ctrl);
}

bsp_pmod_spi_mode_t bsp_pmod_spi_mode(void)
{
  return (pmod_spi_ctrl_shadow & PMOD_SPI_CTRL_QUAD) != 0u
      ? BSP_PMOD_SPI_MODE_QUAD
      : BSP_PMOD_SPI_MODE_SINGLE;
}

void bsp_pmod_spi_set_quad(int enabled)
{
  bsp_pmod_spi_set_mode(enabled ? BSP_PMOD_SPI_MODE_QUAD : BSP_PMOD_SPI_MODE_SINGLE);
}

void bsp_pmod_spi_select(void)
{
  pmod_spi_write_ctrl(pmod_spi_ctrl_shadow & ~PMOD_SPI_CTRL_CSN);
}

void bsp_pmod_spi_deselect(void)
{
  pmod_spi_write_ctrl(pmod_spi_ctrl_shadow | PMOD_SPI_CTRL_CSN);
}

int bsp_pmod_spi_ready(void)
{
  return ((bsp_read32(PMOD_SPI_READY) & 1u) != 0u) &&
         ((bsp_read32(PMOD_SPI_CTRL) & PMOD_SPI_CTRL_BUSY) == 0u);
}

uint32_t bsp_pmod_spi_ctrl(void)
{
  return bsp_read32(PMOD_SPI_CTRL);
}

uint32_t bsp_pmod_spi_rx(void)
{
  return bsp_read32(PMOD_SPI_RX);
}

uint8_t bsp_pmod_spi_xfer8(uint8_t value)
{
  pmod_spi_wait_ready();
  bsp_pmod_spi_set_mode(BSP_PMOD_SPI_MODE_SINGLE);
  bsp_write32(PMOD_SPI_TX, ((uint32_t)value) << 24);
  pmod_spi_wait_ready();
  return (uint8_t)(bsp_read32(PMOD_SPI_RX) & 0xffu);
}

uint32_t bsp_pmod_spi_xfer32(uint32_t value)
{
  pmod_spi_wait_ready();
  bsp_pmod_spi_set_mode(BSP_PMOD_SPI_MODE_QUAD);
  bsp_write32(PMOD_SPI_TX, value);
  pmod_spi_wait_ready();
  return bsp_read32(PMOD_SPI_RX);
}

void bsp_pmod_spi_transfer(const uint8_t *tx, uint8_t *rx, size_t len)
{
  for (size_t i = 0; i < len; ++i) {
    uint8_t out = tx ? tx[i] : 0xffu;
    uint8_t in = bsp_pmod_spi_xfer8(out);
    if (rx) {
      rx[i] = in;
    }
  }
}