From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by oss.sgi.com id ; Wed, 5 Jul 2000 17:28:44 -0700 Received: from f260.law9.hotmail.com ([64.4.8.135]:47114 "HELO hotmail.com") by oss.sgi.com with SMTP id ; Wed, 5 Jul 2000 17:28:20 -0700 Received: (qmail 64368 invoked by uid 0); 6 Jul 2000 00:28:24 -0000 Message-ID: <20000706002824.64367.qmail@hotmail.com> Received: from 208.198.161.2 by www.hotmail.com with HTTP; Wed, 05 Jul 2000 17:28:24 PDT X-Originating-IP: [208.198.161.2] From: "Erik Niessen" To: linux-mips@oss.sgi.com Subject: Doing DMA with the ide-driver Date: Thu, 06 Jul 2000 02:28:24 CEST Mime-Version: 1.0 Content-Type: text/plain; format=flowed Sender: owner-linux-mips@oss.sgi.com Precedence: bulk Return-Path: X-Orcpt: rfc822;linux-mips-outgoing Hello, I am trying to get an external ide-pci controller (CMD 646) working on an embedded mips board. The kernel-source is based on a 2.2.12 source tree. The problem is doing DMA. I receive address (0x80ff0000) for my dmatable in the function ide_setup_dma (__get_free_pages). Then in ide_buildtable it sets up the dmatable. Address 0x80376000 and a count of 0x400 (check_partition reads 2 sectors from the harddrive). These are all virtual addresses. For setting up the dmatable I use physical addresses. On the embedded board there is a 1:1 map of i/o bus to main memory so platform_mem_iobus_base is 0. So after doing the DMA read, I read only zero's at address 0x80376000 and the kernel hangs. But the harddrive is ready and I can't find any errors. It seems that it writes the data to a different memory location. After searching the memory the data is written at address 0x80000000?? Is the memory manager somewhere in between??? The next thing I did was reserving a piece of physical memory for DMA and fill in the dmatable myself. So that it uses my piece of reserved memory. After I did this, the data was at the correct address and the kernel didn't crash. Is this the solution??? Anyone a clue? Thanks, Erik ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com