From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933148Ab1ETNBu (ORCPT ); Fri, 20 May 2011 09:01:50 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:54199 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932678Ab1ETNBs (ORCPT ); Fri, 20 May 2011 09:01:48 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=IR2Ysr9r0K0SFVXngP+N/myY3StsOxDLf6pya+ylv1ttXtnBAHg8W3P9X7kCbLtdtM 1ndfEco3xi1rulDf1vvWCWo0t5/+vZLKuwx0lhvNK3zi0JyOpTRi6Ma++c5x6jgreCLL mStI/GWCE7QDUwpgxtH49M6ljIEvby7ZiMSKg= MIME-Version: 1.0 In-Reply-To: <1305863541.7481.132.camel@pasglop> References: <1305753895-24845-1-git-send-email-ericvh@gmail.com> <1305753895-24845-6-git-send-email-ericvh@gmail.com> <1305851941.7481.92.camel@pasglop> <1305856442.7481.120.camel@pasglop> <4DD5E218.5030508@mcs.anl.gov> <1305863541.7481.132.camel@pasglop> Date: Fri, 20 May 2011 08:01:47 -0500 Message-ID: Subject: Re: [bg-linux] [PATCH 6/7] [RFC] enable early TLBs for BG/P From: Eric Van Hensbergen To: Benjamin Herrenschmidt Cc: Kazutomo Yoshii , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, bg-linux@lists.anl-external.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 19, 2011 at 10:52 PM, Benjamin Herrenschmidt wrote: >> Unfortunately, the firmware is also required: >> - to configure Blue Gene Interrupt Controller(BIC) >> - to configure Torus DMA unit. e.g. fifo >> - to configure global interrupt (even we don't use, we need to disable >> some channel correctly) > > Can't we just write bare metal code for that ? > The kittyhawk code has the bare-metal equivalents for all of these. When I get to the drivers, I'll favor the kittyhawk versions for submission and then we'll see if it would be possible to adapt the HPC extensions to use the bare-metal versions of the drivers versus the firmware interface. >> - to access node personality information (node id, DDR size, HZ, etc) or >> maybe we can directly access SRAM? > > That should be turned into device-tree at boot, possibly from a > bootloader or from the zImage wrapper. > This is the approach is used by the kittyhawk u-boot approach. However, it would also be just as easy to construct an in-memory device-tree within Linux by mapping the personality page and copying the relevant bits out. This has the advantage of being able to boot Linux directly on the nodes without an intermediary boot loader (which kittyhawk uses just to allow us customize which kernel boots on a node-to-node basis whereas the stock system boots the same kernel on all the nodes within a partition allocation (64-40,000 nodes)). -eric