From patchwork Tue Sep 4 02:40:17 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 1401081 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id 1D13F3FC85 for ; Tue, 4 Sep 2012 02:44:14 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1T8j4E-0001FV-F5; Tue, 04 Sep 2012 02:40:42 +0000 Received: from mail-out.m-online.net ([212.18.0.10]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1T8j49-0001ER-3B for linux-arm-kernel@lists.infradead.org; Tue, 04 Sep 2012 02:40:39 +0000 Received: from frontend1.mail.m-online.net (frontend1.mail.intern.m-online.net [192.168.8.180]) by mail-out.m-online.net (Postfix) with ESMTP id 3X9sjH1cwjz3hhb8; Tue, 4 Sep 2012 04:40:35 +0200 (CEST) X-Auth-Info: RKdFfAmUgvldRQOx2YYFpewS8kzH3/mTfuSxkWxhOvU= Received: from mashiro.lan (unknown [195.140.253.167]) by smtp-auth.mnet-online.de (Postfix) with ESMTPA id 3X9sjG6N5gzbbgN; Tue, 4 Sep 2012 04:40:34 +0200 (CEST) From: Marek Vasut To: spi-devel-general@lists.sourceforge.net Subject: [PATCH 3/4] mxs/spi: Decrement the DMA/PIO border Date: Tue, 4 Sep 2012 04:40:17 +0200 Message-Id: <1346726418-2856-4-git-send-email-marex@denx.de> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1346726418-2856-1-git-send-email-marex@denx.de> References: <1346726418-2856-1-git-send-email-marex@denx.de> X-Spam-Note: CRM114 invocation failed X-Spam-Score: -1.9 (-) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-1.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [212.18.0.10 listed in list.dnswl.org] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Marek Vasut , Fabio Estevam , Shawn Guo , Mark Brown , Grant Likely , Chris Ball , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org This driver checks the length of transfer to be made and based on this information, either chooses to transfer data via DMA or PIO. Decrement this border further to gain better performace eg. during SPI flash writes. Empiric measurement shows that this gives extra 3kB/s write speed with a M25P80 flash clocked at 40MHz. Signed-off-by: Marek Vasut Cc: Chris Ball Cc: Fabio Estevam Cc: Grant Likely Cc: Mark Brown Cc: Shawn Guo --- drivers/spi/spi-mxs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/spi/spi-mxs.c b/drivers/spi/spi-mxs.c index 282bdd7..6650ded 100644 --- a/drivers/spi/spi-mxs.c +++ b/drivers/spi/spi-mxs.c @@ -445,7 +445,7 @@ static int mxs_spi_transfer_one(struct spi_master *master, * DMA only: 2.164808 seconds, 473.0KB/s * Combined: 1.676276 seconds, 610.9KB/s */ - if (t->len <= 256) { + if (t->len < 32) { writel(BM_SSP_CTRL1_DMA_ENABLE, ssp->base + HW_SSP_CTRL1(ssp) + STMP_OFFSET_REG_CLR);