MACEPAR_CONTEXT_DATA_BOUND
parport_ip32_dma_setup_context(MACEPAR_CONTEXT_DATA_BOUND);
limit = MACEPAR_CONTEXT_DATA_BOUND -
(parport_ip32_dma.next & (MACEPAR_CONTEXT_DATA_BOUND - 1));
parport_ip32_dma_setup_context(MACEPAR_CONTEXT_DATA_BOUND);