From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Williams Subject: Re: [PATCH 00/11] ARM: PrimeCell DMA Interface v5 Date: Sat, 1 May 2010 16:25:52 -0700 Message-ID: References: <1270681920-4461-1-git-send-email-linus.walleij@stericsson.com> <20100422110025.GC20008@n2100.arm.linux.org.uk> <20100501224429.GA17693@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-pw0-f46.google.com ([209.85.160.46]:33842 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755339Ab0EAXZx convert rfc822-to-8bit (ORCPT ); Sat, 1 May 2010 19:25:53 -0400 In-Reply-To: <20100501224429.GA17693@n2100.arm.linux.org.uk> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Russell King - ARM Linux Cc: Linus Walleij , Linus WALLEIJ , "akpm@linux-foundation.org" , Grant Likely , "linux-arm-kernel@lists.infradead.org" , "linux-mmc@vger.kernel.org" , STEricsson_nomadik_linux , "linux-kernel@vger.kernel.org" On Sat, May 1, 2010 at 3:44 PM, Russell King - ARM Linux wrote: > On Sat, May 01, 2010 at 03:00:09PM -0700, Dan Williams wrote: >> Just to clarify are you nak'ing these patches for upstream inclusion >> until this testing occurs? =A0Or do we just need a !ARCH_VERSATILE >> somewhere to allow any incompatibilities to be worked out later >> in-tree? > > What I don't want to do is to get into the situation where we throw > this patchset into the kernel and then find that we have to invent a > whole new implementation in the various primecell drivers to support > the Versatile hardware. > > Versatile has some MUXing on three of the DMA signals, so (eg) we > really don't want UARTs claiming DMAs just because they're in existen= ce > and not in use - that would prevent DMAs from being used for (eg) AAC= I > or MMC. > > The alternative is that we could just take the attitude that Versatil= e/ > Realview will never have DMA support implemented, but that seems rath= er > silly, as they've tended to be the first platforms I get new CPU > architectures for. =A0(This is why DMA coherency stuff on new archite= ctures > tends to be left for others to do...) Ok, it will be good to have this approach vetted on a challenging arch. We'll see where things stand when the merge window opens. -- Dan