From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3C7A99EF.1AF2F99@mvista.com> Date: Mon, 25 Feb 2002 12:09:19 -0800 From: Armin Kuster MIME-Version: 1.0 To: Gabriel Paubert Cc: Benjamin Herrenschmidt , linuxppc-dev Subject: Re: 405 DMA api References: Content-Type: text/plain; charset=iso-8859-1 Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: Gabriel Paubert wrote: > > On Mon, 25 Feb 2002, Benjamin Herrenschmidt wrote: > > > > > >Hello, > > > > > >I would like to have the 405 dma share the same dma api as the current > > >pmac. I propose to make the asm/dma.h _generic_ and move all the power > > >Mac unique stuff into a seperate file such as "pmac_dma.h". The dma.h > > >would then be the gateway for other ppc archs by using "CONFIG_" > > >to determine which hearder to pull in. I made the pmac_pma.h as the > > >default. I have tested this on the walnut and can only compile for the > > >pmac. I have included a patch and I would like some feedback and to > > >have the pmac_dma verified. > > > > > >files: > > >include/asm-ppc/dma.h <- generic defines and config selection > > >include/asm-ppc/pmac_dma.h <- most code from dma.h > > >include/asm-ppc/ppc405_dma.h <- changed func names > > >arch/ppc/kernel/ppc405_dma.c <- changes to refect new header scheme > > > > Well... except this isn't pmac dma. The pmac has a DBDMA controller > > which is much different from the legacy DMA controller used here. What > > you see in this dma.h file is, I bet, prep stuff. > > True. Itīs the legacy ISA DMA controller which can be found on PreP and > CHRP, almost always in the PCI-ISA bridge. However these are not all > created equal: the one in the WinBond 83C553 in my MVME boards, which is > almost identical to some Intel model (82378ZB), is actually capable of 32 > bit addressing and can do descripto based scatter-gather DMA. However, > since I never used anything that needed DMA on these boards (the floppy > actually) I did not bother to improve the dma driver. > > Some historical note: the 82378ZB, with its improved DMA engine, is AFAICS > the only Intel PCI<->ISA bridge with enhanced DMA capabilities. Also AFAIR > this chip was exactly the one specified in the PreP documentation, > strangely enough, the 82378 production was stopped and the enhanced DMA > capability disappeared from all later Intel PCI<->ISA bridge. My 82378ZB > doc is from March 1996 BTW... > > Regards, > Gabriel. Ok ... thanks for the info. where do we go from here? Can it get push in after a better name is selected? -- armin ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/