From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.primagraphics.com (unknown [81.20.3.25]) by ozlabs.org (Postfix) with SMTP id 0C25A2BDB5 for ; Mon, 13 Dec 2004 20:55:33 +1100 (EST) Message-ID: <41BD657F.7010000@primagraphics.co.uk> Date: Mon, 13 Dec 2004 09:48:47 +0000 From: Mark Powell MIME-Version: 1.0 To: cwernham@airspan.com References: <41B8255A.3040101@airspan.com> In-Reply-To: <41B8255A.3040101@airspan.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linuxppc-dev@ozlabs.org Subject: Re: PPC4XX DMA polarity bug in linuxppc-2.6.9 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Colin Wernham wrote: > I believe that there is a PPC4xx DMA driver bug in the following > kernel, file and function: > linuxppc-2.6.9, > /arch/ppc/syslib/ppc4xx_dma.c, > ppc4xx_init_dma_channel() > > > Is there anyone else using the PPC4XX DMA? FWIW I have used the PPC4xx dma on 405GP systems and a 440GP system with 2.4.21 and 2.4.25. I found the ppc4xx_dma.c functions didn't work in the way I needed. I just read the code very carefully and used a few of the functions combined with some direct manipulation of the DMA registers. As I recall, I don't think the polarity is the only problem in that file. It certainly doesn't support the 440 DMA registers - the COUNT register is different. The code in ppc4xx_dma.c is however, very useful as a guide in how to go about setting up a DMA transfer; just read it carefully with the processor manual to hand. -- Mark Powell, Senior Software Engineer Curtiss-Wright Controls Embedded Computing Tel: +44 (0) 1763 852222 Email: medp@primagraphics.com