From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756999Ab1LWM2k (ORCPT ); Fri, 23 Dec 2011 07:28:40 -0500 Received: from mailout2.w1.samsung.com ([210.118.77.12]:53176 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756835Ab1LWM2H (ORCPT ); Fri, 23 Dec 2011 07:28:07 -0500 Date: Fri, 23 Dec 2011 13:27:32 +0100 From: Marek Szyprowski Subject: [PATCH 13/14] common: DMA-mapping: add WRITE_COMBINE attribute In-reply-to: <1324643253-3024-1-git-send-email-m.szyprowski@samsung.com> To: linux-kernel@vger.kernel.org Cc: Benjamin Herrenschmidt , Thomas Gleixner , Andrew Morton , Arnd Bergmann , Stephen Rothwell , microblaze-uclinux@itee.uq.edu.au, linux-arch@vger.kernel.org, x86@kernel.org, linux-sh@vger.kernel.org, linux-alpha@vger.kernel.org, sparclinux@vger.kernel.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mips@linux-mips.org, discuss@x86-64.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linaro-mm-sig@lists.linaro.org, Jonathan Corbet , Marek Szyprowski , Kyungmin Park , Andrzej Pietrasiewicz Message-id: <1324643253-3024-14-git-send-email-m.szyprowski@samsung.com> MIME-version: 1.0 X-Mailer: git-send-email 1.7.7.3 Content-type: TEXT/PLAIN Content-transfer-encoding: 7BIT References: <1324643253-3024-1-git-send-email-m.szyprowski@samsung.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org DMA_ATTR_WRITE_COMBINE specifies that writes to the mapping may be buffered to improve performance. It will be used by the replacement for ARM/ARV32 specific dma_alloc_writecombine() function. Signed-off-by: Marek Szyprowski Signed-off-by: Kyungmin Park --- Documentation/DMA-attributes.txt | 10 ++++++++++ include/linux/dma-attrs.h | 1 + 2 files changed, 11 insertions(+), 0 deletions(-) diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index b768cc0..811a5d4 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -31,3 +31,13 @@ may be weakly ordered, that is that reads and writes may pass each other. Since it is optional for platforms to implement DMA_ATTR_WEAK_ORDERING, those that do not will simply ignore the attribute and exhibit default behavior. + +DMA_ATTR_WRITE_COMBINE +---------------------- + +DMA_ATTR_WRITE_COMBINE specifies that writes to the mapping may be +buffered to improve performance. + +Since it is optional for platforms to implement DMA_ATTR_WRITE_COMBINE, +those that do not will simply ignore the attribute and exhibit default +behavior. diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h index 71ad34e..ada61e1 100644 --- a/include/linux/dma-attrs.h +++ b/include/linux/dma-attrs.h @@ -13,6 +13,7 @@ enum dma_attr { DMA_ATTR_WRITE_BARRIER, DMA_ATTR_WEAK_ORDERING, + DMA_ATTR_WRITE_COMBINE, DMA_ATTR_MAX, }; -- 1.7.1.569.g6f426