From patchwork Thu Dec 11 06:26:41 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jisheng Zhang X-Patchwork-Id: 5474291 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 26EB8BEEA8 for ; Thu, 11 Dec 2014 06:31:36 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4302F20121 for ; Thu, 11 Dec 2014 06:31:35 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 751A32011D for ; Thu, 11 Dec 2014 06:31:34 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XyxG0-0000CV-LV; Thu, 11 Dec 2014 06:29:48 +0000 Received: from mx0b-0016f401.pphosted.com ([67.231.156.173]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XyxFu-00006a-Tl for linux-arm-kernel@lists.infradead.org; Thu, 11 Dec 2014 06:29:45 +0000 Received: from pps.filterd (m0045851.ppops.net [127.0.0.1]) by mx0b-0016f401.pphosted.com (8.14.5/8.14.5) with SMTP id sBB6PNsc000324; Wed, 10 Dec 2014 22:29:21 -0800 Received: from sc-owa.marvell.com ([199.233.58.135]) by mx0b-0016f401.pphosted.com with ESMTP id 1r6a1y3jyx-1 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT); Wed, 10 Dec 2014 22:29:21 -0800 Received: from maili.marvell.com (10.93.76.43) by SC-OWA.marvell.com (10.93.76.28) with Microsoft SMTP Server id 8.3.327.1; Wed, 10 Dec 2014 22:29:19 -0800 Received: from xhacker.marvell.com (unknown [10.37.135.218]) by maili.marvell.com (Postfix) with ESMTP id 23B583F703F; Wed, 10 Dec 2014 22:29:18 -0800 (PST) From: Jisheng Zhang To: , Subject: [PATCH] i2c: designware: use {readl|writel}_relaxed instead of readl/writel Date: Thu, 11 Dec 2014 14:26:41 +0800 Message-ID: <1418279201-3886-1-git-send-email-jszhang@marvell.com> X-Mailer: git-send-email 2.1.3 MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.13.68, 1.0.33, 0.0.0000 definitions=2014-12-11_01:2014-12-10, 2014-12-11, 1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1402240000 definitions=main-1412110069 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141210_222943_101556_8D9E4F4C X-CRM114-Status: GOOD ( 11.07 ) X-Spam-Score: -0.7 (/) Cc: Jisheng Zhang , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP readl/writel is too expensive especially on Cortex A9 w/ outer L2 cache. This introduces i2c read/write errors on Marvell BG2/BG2Q SoCs when there are heavy L2 cache maintenance operations at the same time. The driver does not perform DMA, so it's safe to use the relaxed version. From another side, the relaxed io accessor macros are available on all architectures now, so we can use the relaxed versions instead. Signed-off-by: Jisheng Zhang Acked-by: Mika Westerberg --- drivers/i2c/busses/i2c-designware-core.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c index 23628b7..e279948 100644 --- a/drivers/i2c/busses/i2c-designware-core.c +++ b/drivers/i2c/busses/i2c-designware-core.c @@ -170,10 +170,10 @@ u32 dw_readl(struct dw_i2c_dev *dev, int offset) u32 value; if (dev->accessor_flags & ACCESS_16BIT) - value = readw(dev->base + offset) | - (readw(dev->base + offset + 2) << 16); + value = readw_relaxed(dev->base + offset) | + (readw_relaxed(dev->base + offset + 2) << 16); else - value = readl(dev->base + offset); + value = readl_relaxed(dev->base + offset); if (dev->accessor_flags & ACCESS_SWAP) return swab32(value); @@ -187,10 +187,10 @@ void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset) b = swab32(b); if (dev->accessor_flags & ACCESS_16BIT) { - writew((u16)b, dev->base + offset); - writew((u16)(b >> 16), dev->base + offset + 2); + writew_relaxed((u16)b, dev->base + offset); + writew_relaxed((u16)(b >> 16), dev->base + offset + 2); } else { - writel(b, dev->base + offset); + writel_relaxed(b, dev->base + offset); } }