From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id BFC716B010B for ; Mon, 20 Jun 2011 11:23:29 -0400 (EDT) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=us-ascii Received: from eu_spt1 ([210.118.77.14]) by mailout4.w1.samsung.com (Sun Java(tm) System Messaging Server 6.3-8.04 (built Jul 29 2009; 32bit)) with ESMTP id <0LN3008F2HF2VY10@mailout4.w1.samsung.com> for linux-mm@kvack.org; Mon, 20 Jun 2011 16:23:26 +0100 (BST) Received: from linux.samsung.com ([106.116.38.10]) by spt1.w1.samsung.com (iPlanet Messaging Server 5.2 Patch 2 (built Jul 14 2004)) with ESMTPA id <0LN3002RUHF17F@spt1.w1.samsung.com> for linux-mm@kvack.org; Mon, 20 Jun 2011 16:23:25 +0100 (BST) Date: Mon, 20 Jun 2011 17:23:22 +0200 From: Marek Szyprowski Subject: RE: [PATCH 4/8] ARM: dma-mapping: implement dma sg methods on top of generic dma ops In-reply-to: <20110620144012.GE26089@n2100.arm.linux.org.uk> Message-id: <000801cc2f5d$fdd720a0$f98561e0$%szyprowski@samsung.com> Content-language: pl References: <1308556213-24970-1-git-send-email-m.szyprowski@samsung.com> <1308556213-24970-5-git-send-email-m.szyprowski@samsung.com> <20110620144012.GE26089@n2100.arm.linux.org.uk> Sender: owner-linux-mm@kvack.org List-ID: To: 'Russell King - ARM Linux' Cc: linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, 'Kyungmin Park' , 'Arnd Bergmann' , 'Joerg Roedel' , Marek Szyprowski Hello, On Monday, June 20, 2011 4:40 PM Russell King - ARM Linux wrote: > On Mon, Jun 20, 2011 at 09:50:09AM +0200, Marek Szyprowski wrote: > > This patch converts all dma_sg methods to be generic (independent of the > > current DMA mapping implementation for ARM architecture). All dma sg > > operations are now implemented on top of respective > > dma_map_page/dma_sync_single_for* operations from dma_map_ops structure. > > No. We really don't want to do this. I assume you want to keep the current design for performance reasons? It's really not a problem for me. I can change my patches to keep arm_dma_*_sg_* functions and create some stubs for dmabounce version. > If we want to move the dsb() out of the mapping functions (which I > have a patch for) to avoid doing a dsb() on each and every sg segment, > then we must not use the generic stuff. Ok, specialized (optimized) version of dma_*_sg_* operations are definitely better. The current version just calls respective dma_single_* operations in a loop, so in my patches I decided to create some generic version just to simplify the code. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org