Scott Wood <scottw...@freescale.com> wrote on 30/03/2009 19:45:17: > > Joakim Tjernlund wrote: > > Scott Wood <scottw...@freescale.com> wrote on 30/03/2009 19:22:03: > >> Joakim Tjernlund wrote: > >>> gianfar does not seem to use in_/out_ functions for the BDs. Works > > just > >>> fine that too it seems. > >> It does now that it has explicit barriers in a few places. Before they > > > > In 2.6.29 or later? > > No, it was earlier.
Ah, I see now. The eieio() stuff. > > >> were added, it would sometimes fail under load. That was due to a > >> compiler reordering, but CPU reordering was possible as well. > > > > Does not the CPU skip reordering if the guarded bit is set? > > The guarded bit is typically not set for DMA buffers. ucc_geth is a bit > different since descriptors are in MURAM which is ioremap()ed -- though > switching to a cacheable mapping with barriers should be a performance > improvement. I always thought that MURAM was very fast. The whole reason to have BDs in MURAM is that it is faster than normal RAM, at least that is what I thought. Jocke _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
