simultaneous map of DMA read and write buffers

• From: Alex Fielding <afielding_at_adelphia.net>
• Date: Mon, 10 May 2004 00:56:03 -0400

How does one simulaneously map the read and write DMA buffers? The way I
have it now, mmap returns a pointer to the same memory location, that
appears to be relevant to DMA read.

comedi_config /dev/comedi0 ni_pcimio --read_buffer 1024 --write_buffer 1024

RxBufSize= comedi_get_buffer_size(dev,0); // adc buffer (returns 1048576)
TxBufSize= comedi_get_buffer_size(dev,1); // dac buffer (returns 1048576)

RxMap= mmap(NULL, RxBufSize, PROT_READ, MAP_SHARED, comedi_fileno(dev), 0);
TxMap= mmap(NULL, TxBufSize, PROT_READ, MAP_SHARED, comedi_fileno(dev), 0);

Received on 2004-05-10Z03:56:03