From patchwork Thu May 19 18:01:25 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Linus Walleij X-Patchwork-Id: 798282 Received: from bombadil.infradead.org (bombadil.infradead.org [18.85.46.34]) by demeter2.kernel.org (8.14.4/8.14.3) with ESMTP id p4JI3pMV024705 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 19 May 2011 18:04:13 GMT Received: from canuck.infradead.org ([2001:4978:20e::1]) by bombadil.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QN7Xz-0008Gq-4z; Thu, 19 May 2011 18:02:07 +0000 Received: from localhost ([127.0.0.1] helo=canuck.infradead.org) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1QN7Xx-0007Py-Cd; Thu, 19 May 2011 18:02:05 +0000 Received: from eu1sys200aog119.obsmtp.com ([207.126.144.147]) by canuck.infradead.org with smtps (Exim 4.76 #1 (Red Hat Linux)) id 1QN7Xs-0007Pe-Si for linux-arm-kernel@lists.infradead.org; Thu, 19 May 2011 18:02:01 +0000 Received: from beta.dmz-us.st.com ([167.4.1.35]) (using TLSv1) by eu1sys200aob119.postini.com ([207.126.147.11]) with SMTP ID DSNKTdVbDLURihmpa88FoILYsYOq+NfWGNZT@postini.com; Thu, 19 May 2011 18:02:00 UTC Received: from zeta.dmz-us.st.com (ns4.st.com [167.4.16.71]) by beta.dmz-us.st.com (STMicroelectronics) with ESMTP id 000183C; Thu, 19 May 2011 18:01:32 +0000 (GMT) Received: from relay2.stm.gmessaging.net (unknown [10.230.100.18]) by zeta.dmz-us.st.com (STMicroelectronics) with ESMTP id 6945D61; Thu, 19 May 2011 18:01:32 +0000 (GMT) Received: from exdcvycastm004.EQ1STM.local (alteon-source-exch [10.230.100.61]) (using TLSv1 with cipher RC4-MD5 (128/128 bits)) (Client CN "exdcvycastm004", Issuer "exdcvycastm004" (not verified)) by relay2.stm.gmessaging.net (Postfix) with ESMTPS id D44FBA8065; Thu, 19 May 2011 20:01:24 +0200 (CEST) Received: from localhost.localdomain (10.230.100.153) by smtp.stericsson.com (10.230.100.2) with Microsoft SMTP Server (TLS) id 8.3.83.0; Thu, 19 May 2011 20:01:32 +0200 From: Linus Walleij To: Grant Likely , Subject: [PATCH] spi/pl022: use cpu_relax in the busy loop Date: Thu, 19 May 2011 20:01:25 +0200 Message-ID: <1305828085-25135-1-git-send-email-linus.walleij@stericsson.com> X-Mailer: git-send-email 1.7.3.2 MIME-Version: 1.0 X-CRM114-Version: 20090807-BlameThorstenAndJenny ( TRE 0.7.6 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20110519_140201_238202_1DC572E8 X-CRM114-Status: GOOD ( 14.40 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.3.1 on canuck.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [207.126.144.147 listed in list.dnswl.org] Cc: Linus Walleij , Lee Jones , Linus Walleij , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Thu, 19 May 2011 18:04:13 +0000 (UTC) This relaxes the cpu in the polling busy-wait loop. Reported-by: Vitaly Wool Signed-off-by: Linus Walleij --- drivers/spi/amba-pl022.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/drivers/spi/amba-pl022.c b/drivers/spi/amba-pl022.c index 18667de..8a2b88a 100644 --- a/drivers/spi/amba-pl022.c +++ b/drivers/spi/amba-pl022.c @@ -1424,6 +1424,7 @@ static void do_polling_transfer(struct pl022 *pl022) message->state = STATE_ERROR; goto out; } + cpu_relax(); } /* Update total byte transferred */