From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jared Hulbert" Subject: Re: [PATCH 00/10] AXFS: Advanced XIP filesystem Date: Mon, 15 Sep 2008 12:43:00 -0700 Message-ID: <6934efce0809151243h60a6e48bpf0c7600d4badf3c4@mail.gmail.com> References: <6934efce0809121452kd20deb6m268715f6ed83a71e@mail.gmail.com> <20080915163421.GA13631@shareable.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=s+miAZFB4TZl6JjN+GV4vlV42t2DxyvjLOrjHpp4z8Q=; b=v5aLZpGmIRzismCR4y1zMduxRzCH7yQm40khniStiL1ThigmtmNGwwHcwLB0C0k+cw N5bbL3nKFsRRi4WrG5Fpf8hUlOQqc4EJQGVw0bAxQ4fKJ12Z/RaL8+K0jhlg8Hk3k8Br 0FqHdMZOm1v3bg2zXSGi7DMzOVixpPrGuvYBU= In-Reply-To: <20080915163421.GA13631@shareable.org> Content-Disposition: inline Sender: linux-embedded-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Jamie Lokier Cc: Greg Ungerer , Linux-kernel@vger.kernel.org, linux-embedded@vger.kernel.org, linux-mtd , =?UTF-8?Q?J=C3=B6rn_Engel?= , tim.bird@am.sony.com, cotte@de.ibm.com, nickpiggin@yahoo.com.au >> >> I'm using Spansion MirrorBit S29GL128N, which reads at about 0.6 MByte/s. >> >> If you are using a GL, you'll probably find our P33 a good fit and at >> competitive prices to GL as I understand it. That's I think 50Mhz. > > What's a GL? Never heard of it - all I can think of is OpenGL :-) S29_GL_128N > I'm not sure if cache is an option with this device - but would it > make a difference anyway? Well the first read takes 100ns (plus the other chipset overhead 300ns) but other reads in a page are only an extra 25ns each. So your benefit is not from having the entire executable in cache it's from having the next 7 instructions in the cacheline for only an extra 25ns each instead of 400ns. > Interesting, thanks. I'm not sure it's possible to change the way NOR > is being used with this chip, and it'll be a while before it's > economical to replace the board with a new design. Usually these things can be fixed in the bootloader or by hacking the kernel to tweak the relevant chipset registers.