From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Joe Woodward" Subject: OMAP3 L2/outer cache enabled in kernel (after being disabled by uBoot)? Date: Mon, 16 Jan 2012 10:03:44 +0000 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Received: from smtp1.keele.netcentral.co.uk ([212.57.235.197]:57462 "EHLO smtp3.keele.netcentral.co.uk" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751896Ab2APKEK (ORCPT ); Mon, 16 Jan 2012 05:04:10 -0500 Received: from terrafix.co.uk (reverse.keele.netcentral.co.uk [212.57.249.250] (may be forged)) by smtp3.keele.netcentral.co.uk (8.14.2/8.14.2) with ESMTP id q0GA42MO015125 for ; Mon, 16 Jan 2012 10:04:07 GMT Received: from WorldClient by terrafix.co.uk (MDaemon PRO v12.5.2) with ESMTP id md50002145344.msg for ; Mon, 16 Jan 2012 10:04:02 +0000 Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: linux-omap@vger.kernel.org The latest uBoot release (2011.12) disables the L2/outer cache during boot on OMAP boards. uBoot commit: "armv7: disable L2 cache in cleanup_before_linux()" on 6th Dec 2011 by Aneesh V adds the following to uBootSources/arch/arm/cpu/armv7/cpu.c:cleanup_before_linux(): ... v7_out_cache_disable(); The commit message implies this change was to make booting reliable on OMAP4 by disabling L2 cache before jumping to Linux. Sadly this commit also affects OMAP3-based boards... Since switching to uBoot 2011.12 I'm seeing about half the performance on my GUSMTIX Overo (OMAP3530). In the kernel sources there seem to be OMAP4 specific functions for re-enabling the L2 cache (omap4-common.c:omap_l2_cache_init()), but none for OMAP3. So my question is... do we expect that Linux should be re-enabling the L2/outer cache during boot after uBoot has disabled it on OMAP3? Cheers, Joe (See http://lists.denx.de/pipermail/u-boot/2012-January/115056.html for uBoot mailing list on this subject)