tx_fifo_level
u32 tx_fifo_level = ax_spi_read(xspi, AX_SPI_TX_FBCAR);
if (tx_fifo_level == 0)
return spi->tx_fifo_size - tx_fifo_level(spi);
else if (!tx_fifo_level(spi))
for (; i2s->tx_fifo_level < i2s->tx_fifo_high; \
i2s->tx_fifo_level += 2) { \
i2s->tx_fifo_level = i2s->tx_fifo_low;
i2s->tx_fifo_level = 0;
i2s->tx_fifo_level = i2s->tx_fifo_low;
unsigned tx_fifo_level;