Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756594Ab0G1XMv (ORCPT ); Wed, 28 Jul 2010 19:12:51 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:63979 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751610Ab0G1XMu convert rfc822-to-8bit (ORCPT ); Wed, 28 Jul 2010 19:12:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=H/R51kxRHbj3SCtZdY5ELemzQftoYjkerauoOTM360b93WT28iLIPRQ17oV2YO6EpL gIndC4yvqy0m3LH91XlbO4U4crkoM6Xk1N0YcHvGecwhkH/Jr07NUsNtv2DdW8WpIp9g ps2aT4JGEi9RoxjFcDrfIaYKtRYK5a1uImW4g= MIME-Version: 1.0 In-Reply-To: References: <1277811391-17966-1-git-send-email-linus.walleij@stericsson.com> Date: Thu, 29 Jul 2010 01:12:48 +0200 Message-ID: Subject: Re: [PATCH 2/2] DMAENGINE: driver for the ARM PL080/PL081 PrimeCells From: Linus Walleij To: Dan Williams Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, yuanyabin1978@sina.com, Peter Pearse , Ben Dooks , Kukjin Kim , Alessandro Rubini , Viresh Kumar , Russell King Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2241 Lines: 56 2010/7/28 Dan Williams : > On Tue, Jun 29, 2010 at 4:36 AM, Linus Walleij > wrote: >> This creates a DMAengine driver for the ARM PL080/PL081 PrimeCells >> based on the implementation earlier submitted by Peter Pearse. >> This is working like a charm for memcpy and slave DMA to the PL011 >> PrimeCell on the PB11MPCore. > > Russell I am assuming this implementation and testing is sufficient to > allay your prior nak [1]? ?Linus is oversubscribing virtual channels > to physical channels to handle muxing. I don't think Russell has ever NAK:ed the PL08x driver(s). The NAK was about the PrimeCell DMA extenstions to amba-pl011.c etc. (Still I'm happy if Russell looks at this thing of course.) This patch along with the generic channel control removed the cross-dependency between the PrimeCell DMA patchset and the drivers/dma DMA engine framework (yay!) so there is no arch/arm or AMBA stuff involved anymore, other than the fact that this driver sits on the AMBA/PrimeCell bus. >> +#ifdef MODULE >> + >> +# error "AMBA PL08X DMA CANNOT BE COMPILED AS A LOADABLE MODULE AT PRESENT" >> + >> +/* >> + ? ? ? a) Some devices might make use of DMA during boot >> + ? ? ? ? ?(esp true for DMAENGINE implementation) >> + ? ? ? b) Memory allocation will need much more attention >> + ? ? ? ? ?before load/unload can be supported >> + */ >> +#endif > > This is taken care of by being "config bool", but I assume you want > this for documentation purposes? Peter had that in and I didn't remove it. If you don't like it you can remove it or I can send a new patch. >> + ? ? ? txd = kzalloc(sizeof(struct pl08x_txd), GFP_KERNEL); > > ...appears in the prep routines. ?Will this driver be used by any > storage controllers on the platfom? ?Might we deadlock waiting on i/o > that needs to allocate a descriptor to complete? I haven't noticed anything but a descriptor pool is on my list of things to look into and fix. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/