The following list of Web sites provides additional information on modifying device drivers and configuring the Linux kernel.
Information on Dynamic DMA mapping is available at http://lwn.net/2001/0712/a/dma-interface.php3.
Kernel-HOWTO is available from the Linux Documentation Project at http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html.
Linux Device Drivers, 2nd Edition published by O'Reilly is available online at http://www.xml.com/ldd/chapter/book/index.html.