From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 07/24] C6X: memory management Date: Wed, 17 Aug 2011 15:34:35 +0200 Message-ID: <201108171534.36007.arnd@arndb.de> References: <1312839879-13592-1-git-send-email-msalter@redhat.com> <201108091827.40045.arnd@arndb.de> <1313587573.2306.12.camel@deneb.redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.17.10]:54302 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750887Ab1HQNel (ORCPT ); Wed, 17 Aug 2011 09:34:41 -0400 In-Reply-To: <1313587573.2306.12.camel@deneb.redhat.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Mark Salter Cc: linux-arch@vger.kernel.org On Wednesday 17 August 2011, Mark Salter wrote: > C6X is never consistent in that there is no hw snooping between main > memory and L2 cache. There is some cache control however which allows > us to create a pool of uncached memory for use as consistent DMA memory. > I think the __dma_is_coherent tries to tell at runtime if the dma handle > comes from such a pool of consistent memory. > > I'm not aware of any drivers actually needing this although I'm sure TI > has some. For the purpose of getting the arch accepted, I could just > punt and take it out for now, simplifying the dma support. It can be > revisited later if needed. Yes, sounds good. Not sure if you meant removing all calls to arch_is_coherent() as well, but I'd suggest you do that, too. This should further simplify the code by removing code paths that are unused and untested. Arnd