STM32_MDMA_CBNDTR
stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id)));
stm32_mdma_write(dmadev, STM32_MDMA_CBNDTR(id), hwdesc->cbndtr);
cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id));
cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id));