From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 21 Oct 2010 14:58:15 +0200 (CEST) Received: from h5.dl5rb.org.uk ([81.2.74.5]:37257 "EHLO h5.dl5rb.org.uk" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S1491137Ab0JUM6M (ORCPT ); Thu, 21 Oct 2010 14:58:12 +0200 Received: from h5.dl5rb.org.uk (localhost.localdomain [127.0.0.1]) by h5.dl5rb.org.uk (8.14.4/8.14.3) with ESMTP id o9LCwAV9006816; Thu, 21 Oct 2010 13:58:10 +0100 Received: (from ralf@localhost) by h5.dl5rb.org.uk (8.14.4/8.14.4/Submit) id o9LCw9xd006814; Thu, 21 Oct 2010 13:58:09 +0100 Date: Thu, 21 Oct 2010 13:58:09 +0100 From: Ralf Baechle To: Kevin Cernekee Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 8/9] MIPS: Honor L2 bypass bit Message-ID: <20101021125809.GA15031@linux-mips.org> References: <74b5d3ba9506b2e6d885546bd6dcdaec@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <74b5d3ba9506b2e6d885546bd6dcdaec@localhost> User-Agent: Mutt/1.5.21 (2010-09-15) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 28183 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Wed, Oct 20, 2010 at 08:05:42PM -0700, Kevin Cernekee wrote: > On many of the newer MIPS32 cores, CP0 CONFIG2 bit 12 (L2B) indicates > that the L2 cache is disabled and therefore Linux should not attempt > to use it. I did a bit of research in the meantime. Turns out that some MIPS customers are using their own L2 cache controller. That means a simple check by the CPU PrID is not sufficient and we will need some sort of platform-specific probe, sigh. I've moved all the code your patch adds to a separate function and added a comment so at least people working on platforms with different L2 conntrollers will have a small chance of figuring out what mine blew up under their feet. Ralf