From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3E765932.7040206@embeddededge.com> Date: Mon, 17 Mar 2003 18:24:34 -0500 From: Dan Malek MIME-Version: 1.0 To: "Penn, John" Cc: linuxppc-embedded@lists.linuxppc.org Subject: Re: 8250 idma problem - cache? References: Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Penn, John wrote: > ...I seem > to have a transmit problem that could be explained > by the dcache holding the packet, I guess you mean you wrote something into memory and the IDMA didn't move it to the device on the local bus? Can you use a bus analyzer to ensure the IDMA actually ran as expected? What DMA mode are you using? > snooping - tried enabling it on tx DGBL, no difference > SIUMCR - ESE is enabled If I understand "transmitting", that would be from main memory to the device, so you need to set SGBL. > using local bus memory instead of 603 memory for buffers > I would rather use 603 memory If you have a device on the local bus, that would be a wise choice. :-) > the 8260 is fully cache coherent so you don't have > to invalidate the dcache. That's true, but in the case of transmitting you wouldn't want to invalidate, you would want to flush. > Now I am at the point of needing some clarification. > > 1. Do I have to invalidate dcache and if so how? You do not need to do this. > 2. Has anyone used the IDMA with 603 memory or must > I use local bus memory? The system (603) memory works fine, it just sounds like you need to ensure the channel is correctly configured and your device protocol on the local bus is working correctly. Thanks. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/