Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751689AbWEKNPz (ORCPT ); Thu, 11 May 2006 09:15:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751694AbWEKNPz (ORCPT ); Thu, 11 May 2006 09:15:55 -0400 Received: from nf-out-0910.google.com ([64.233.182.186]:36031 "EHLO nf-out-0910.google.com") by vger.kernel.org with ESMTP id S1751689AbWEKNPy convert rfc822-to-8bit (ORCPT ); Thu, 11 May 2006 09:15:54 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=e+cBy7xz3D725DpiHPoth82VDSy3UMkASklV1yfmunBrzaN3L1Fv3eBXbvmy20KlAFhuwYkyOsRaatqPN+0loC2ea3S865YKpqTBK+pd3JxK/LMJTQTMZ+Op6kjxqV3ipCMlf881TYffQIgEiBkKdVTASexrjwS1uvC7WMvhX7g= Message-ID: Date: Thu, 11 May 2006 15:15:53 +0200 From: "Carlos Ojea Castro" To: "Lennart Sorensen" Subject: Re: LPC bus in a geode sc1200 Cc: linux-kernel@vger.kernel.org In-Reply-To: <20060510153950.GE2835@csclub.uwaterloo.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: <20060509142851.GA2837@csclub.uwaterloo.ca> <20060510153950.GE2835@csclub.uwaterloo.ca> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1844 Lines: 38 On 5/10/06, Lennart Sorensen wrote: > On Wed, May 10, 2006 at 09:55:47AM +0200, Carlos Ojea Castro wrote: > > Thank you very much for your reply, Len. > > I will also have an FPGA (I think it will be on port 0x1400 or so). I > > am writing to LPC using 'outb' like this: outb (data, port); > > So I see an I/O write on the LPC bus, that is: 2 bytes for address and > > 1 byte for data (it tooks one microsecond per transfer). > > > > To speed up things, I wish to transmit more than 1 byte for data in > > each transfer (if possible). > > Accordingly with page 194 of the sc1200 processor data book, it is > > also possible to do a "Bus Master Memory Write" to transmit 1,2 or 4 > > bytes. > > Do you know how can I make a "Bus Master Memory Write" to the LPC? > > Well I know we don't do that. We have very little data, just board > status information from various places on the board. LPC does support > doing DMA, which I believe is done in the same way it was done on ISA at > least as far as the software is concerned. How to implement DMA for LPC > in the FPGA I have no idea. The LPC specifications would probably tell > you. I imagine it involves setting up a DMA buffer in RAM (in the first > 16MB probably) and then sending a command to the FPGA telling it to do a > DMA transfer from that memory location using the LPC DMA commands. > > Len Sorensen Well at this moment, using the low address byte to transmit data, I can transmit 100.000 bytes in about 63 milliseconds, maybe it is enough. Will try DMA anyway... Thank you very much! Regards, Carlos - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/