From patchwork Mon May 10 10:42:34 2010
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
X-Patchwork-Submitter: Oskar Schirmer <os@emlix.com>
X-Patchwork-Id: 98144
Received: from vger.kernel.org (vger.kernel.org [209.132.180.67])
	by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o4AAgiji007702
	for <patchwork-linux-input@patchwork.kernel.org>;
	Mon, 10 May 2010 10:42:44 GMT
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1756574Ab0EJKmo (ORCPT
	<rfc822;patchwork-linux-input@patchwork.kernel.org>);
	Mon, 10 May 2010 06:42:44 -0400
Received: from mx1.emlix.com ([193.175.82.87]:53994 "EHLO mx1.emlix.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1752849Ab0EJKmn (ORCPT <rfc822;linux-input@vger.kernel.org>);
	Mon, 10 May 2010 06:42:43 -0400
Received: from gate.emlix.com ([193.175.27.217]:41651 helo=mailer.emlix.com)
	by mx1.emlix.com with esmtp (Exim 4.69)
	(envelope-from <os@emlix.com>)
	id 1OBQRX-0003Xx-Ox; Mon, 10 May 2010 12:42:35 +0200
Received: by mailer.emlix.com
	id 1OBQRW-0005hI-Fh; Mon, 10 May 2010 12:42:35 +0200
Received: by mango (sSMTP sendmail emulation);
	Mon, 10 May 2010 12:42:34 +0200
From: "Oskar Schirmer" <os@emlix.com>
To: Michael Hennerich <Michael.Hennerich@analog.com>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>,
	Andrew Morton <akpm@linux-foundation.org>, linux-input@vger.kernel.org,
	linux-kernel@vger.kernel.org, Oskar Schirmer <os@emlix.com>,
	=?utf-8?q?Daniel=20Gl=C3=B6ckner?= <dg@emlix.com>,
	Oliver Schneidewind <osw@emlix.com>, Johannes Weiner <jw@emlix.com>
Subject: [PATCH v3] ad7877: keep dma rx buffers in seperate cache lines
Date: Mon, 10 May 2010 12:42:34 +0200
Message-Id: <1273488154-2993-1-git-send-email-os@emlix.com>
In-Reply-To: <1273487642-2169-1-git-send-email-os@emlix.com>
References: <1273487642-2169-1-git-send-email-os@emlix.com>
MIME-Version: 1.0
Organization: emlix gmbh, Goettingen, Germany
Sender: linux-input-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-input.vger.kernel.org>
X-Mailing-List: linux-input@vger.kernel.org
X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by
	milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]);
	Mon, 10 May 2010 10:42:52 +0000 (UTC)


diff --git a/drivers/input/touchscreen/ad7877.c b/drivers/input/touchscreen/ad7877.c
index 885354c..9ebb1b4 100644
--- a/drivers/input/touchscreen/ad7877.c
+++ b/drivers/input/touchscreen/ad7877.c
@@ -153,15 +153,29 @@ enum {
  */
 
 struct ser_req {
+	u16			sample;
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+	char			__padalign[L1_CACHE_BYTES - sizeof(u16)];
+
 	u16			reset;
 	u16			ref_on;
 	u16			command;
-	u16			sample;
 	struct spi_message	msg;
 	struct spi_transfer	xfer[6];
 };
 
 struct ad7877 {
+	u16			conversion_data[AD7877_NR_SENSE];
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+	char			__padalign[L1_CACHE_BYTES -
+					AD7877_NR_SENSE * sizeof(u16)];
+
 	struct input_dev	*input;
 	char			phys[32];
 
@@ -182,8 +196,6 @@ struct ad7877 {
 	u8			averaging;
 	u8			pen_down_acc_interval;
 
-	u16			conversion_data[AD7877_NR_SENSE];
-
 	struct spi_transfer	xfer[AD7877_NR_SENSE + 2];
 	struct spi_message	msg;