On Wed, 2008-10-08 at 12:51 -0700, Kevin Diggs wrote: > Hi, > > I thought I might take a whack at fixing the 2.6 serial driver > for my 8600. At the top of pmac_zilog.c (2.6.26) there is a todo for DMA. > A quick glance at macserial.c (2.4.31) suggests it has dbdma support for > receive. Anyone know of any pitfalls for adding dbdma support for > pmac_zilog.c?
Yes, it's not totally trivial and I wouldn't recommend using the weirdo code in macserial (it does things that I don't understand how they work with the dbdma engine). The best way I see is to start from scratch with two different mechanisms: - For Tx, that's the easiest, the fire off DMA's for outgoing chars, maybe queue up a few descriptors to let data accumulate. - For Rx, one descriptor per byte. That sucks but I think that's also what Apple does. No need to have a huge Rx buffer anyway. That gives you precise Rx status to the byte. Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev