TX_DMA_ENABLE
if (buff_stat & TX_DMA_ENABLE) {
ptxd->buff_stat = lower_32_bits(pDB->dma_addr) | TX_DMA_ENABLE;
reg_val_DMACR |= TX_DMA_ENABLE;
writel(reg_val_DMACR & ~TX_DMA_ENABLE, msp->registers + MSP_DMACR);