From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934224Ab2JXCY5 (ORCPT ); Tue, 23 Oct 2012 22:24:57 -0400 Received: from mx.scalarmail.ca ([98.158.95.75]:42550 "EHLO ironport-01.sms.scalar.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755785Ab2JXCYy (ORCPT ); Tue, 23 Oct 2012 22:24:54 -0400 Date: Tue, 23 Oct 2012 17:17:42 -0400 From: Nick Bowler To: Josh Cartwright Cc: Rob Herring , Arnd Bergmann , arm@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, John Linn Subject: Re: [PATCH v2 2/4] zynq: move static peripheral mappings Message-ID: <20121023211742.GA14047@elliptictech.com> References: <20121022211219.GC31538@beefymiracle.amer.corp.natinst.com> <201210231450.11540.arnd@arndb.de> <5086F973.6050309@gmail.com> <20121023205304.GJ20593@beefymiracle.amer.corp.natinst.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121023205304.GJ20593@beefymiracle.amer.corp.natinst.com> Organization: Elliptic Technologies Inc. User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2012-10-23 15:53 -0500, Josh Cartwright wrote: > On Tue, Oct 23, 2012 at 03:09:23PM -0500, Rob Herring wrote: > > On 10/23/2012 09:50 AM, Arnd Bergmann wrote: > > > On Monday 22 October 2012, Josh Cartwright wrote: > > >> -#define SCU_PERIPH_PHYS 0xF8F00000 > > >> -#define SCU_PERIPH_VIRT SCU_PERIPH_PHYS > > >> +#define SCU_PERIPH_PHYS 0xF8F00000 > > >> +#define SCU_PERIPH_SIZE SZ_8K > > >> +#define SCU_PERIPH_VIRT (PL310_L2CC_VIRT - SCU_PERIPH_SIZE) > > > > > > And your patch 3 already obsoletes this mapping. > > > > Actually, it's probably still needed. The smp platform code typically > > reads the number of cores from the SCU and the mapping has to be in > > place before ioremap is up. I don't think there is an architected way to > > get the number of cores, but it would be nice to avoid this early SCU > > access. We could also mandate getting the core count from DT instead. > > > > Also, the physical address can be read with this on A9's: > > > > asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base)); > > For the sake of the zynq cleanups, I think it may still make sense to > remove the SCU peripheral mappings for now. By the time we're ready to > push in SMP support for zynq, maybe we can tackle the problem of how to > solve the SCU mapping problem generically. Then the static mapping can be removed if and when the we "solve the SCU mapping problem generically". There's no point in removing it until then since it doesn't cause any actual problems, does it? Cheers, -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)