From patchwork Sat Sep 12 21:08:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 258221 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8860C2D0E1 for ; Sat, 12 Sep 2020 21:08:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 869D820829 for ; Sat, 12 Sep 2020 21:08:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="HY13hSv3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725952AbgILVIq (ORCPT ); Sat, 12 Sep 2020 17:08:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725925AbgILVIU (ORCPT ); Sat, 12 Sep 2020 17:08:20 -0400 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C866BC061757 for ; Sat, 12 Sep 2020 14:08:19 -0700 (PDT) Received: by mail-pg1-x542.google.com with SMTP id 34so8675037pgo.13 for ; Sat, 12 Sep 2020 14:08:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=lNyBzqYxhNLfRyzcGYVhpsNYZE01k6vdArIGmMCZyP4=; b=HY13hSv3vsmDbVwvsXcGM1uwa9ssg1EaF0jrXqrOxFlN9zlWG928ZYfHs81NzfcTzB M2M6AgkZ5clA0Vw+h0s8afCY+On1qQfAcpHnOOz/Kj7rY+9H3WBU996zkr9qy9t/T3T2 Sb146Z4Fh3WT70BYQuGvrkIzyVAd7UGgJ4rfg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=lNyBzqYxhNLfRyzcGYVhpsNYZE01k6vdArIGmMCZyP4=; b=rg7EXyOt+wRpG66fC+TqzMJvOQNtRsjOKhmYGmpLT3oXTCGzG1UDaJ5/gYyiep/+os MQ56TZmow7GGvqBPD0s50DbS5RUT9rzKoVFNcD/TIGG2QPOdp1wqmGEFiTqji952Uw0s SHbVgwnoO1/SBEQ9JVTZzpMu0L1ZUUG8CFA3l5xg8AmI8Lisq8v/aqo65D5FBTqoRvgJ unxz1XdndjA/ko3xZIZV4SgkZm/WRv1Dy4VQ3Zlgn6ipALnmJmsk4hWuRChZKVkM1Kt0 h0IqBpH9GkWpsxblsbUKpB/JSwHlGv8M7jDOADKh9rt/mgZg2tz7vckPHEqCmoDe8+86 +ncw== X-Gm-Message-State: AOAM531FlKyJdARqLbZR0NHrh5llFvoWvzaT/hJFbg9gd2jF1J3gnnw5 9XImRHIGeDzT6pfUYGTfwe+rEA== X-Google-Smtp-Source: ABdhPJw7Hcc5QSI5JuRjeZo+HyHcn5RCuI7pIwHNcKnmRxgH6mJMLxHWdY8tE5JD+7KF58ozETdhvA== X-Received: by 2002:a63:4418:: with SMTP id r24mr5829295pga.8.1599944899358; Sat, 12 Sep 2020 14:08:19 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:42b0:34ff:fe3d:58e6]) by smtp.gmail.com with ESMTPSA id e10sm3369020pgb.45.2020.09.12.14.08.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 12 Sep 2020 14:08:18 -0700 (PDT) From: Douglas Anderson To: Mark Brown Cc: Akash Asthana , swboyd@chromium.org, Douglas Anderson , Andy Gross , Bjorn Andersson , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org Subject: [PATCH 3/3] spi: spi-geni-qcom: Slightly optimize setup of bidirectional xfters Date: Sat, 12 Sep 2020 14:08:01 -0700 Message-Id: <20200912140730.3.Ided778fb4cd078e36c6b240d1b279cd7a534a313@changeid> X-Mailer: git-send-email 2.28.0.618.gf4bc123cb7-goog In-Reply-To: <20200912140730.1.Ie67fa32009b94702d56232c064f1d89065ee8836@changeid> References: <20200912140730.1.Ie67fa32009b94702d56232c064f1d89065ee8836@changeid> MIME-Version: 1.0 Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org When setting up a bidirectional transfer we need to program both the TX and RX lengths. We don't need a memory barrier between those two writes. Factor out the __iowmb() and use writel_relaxed(). This saves a fraction of a microsecond of setup overhead on bidirectional transfers. Signed-off-by: Douglas Anderson Reviewed-by: Bjorn Andersson Reported-by: kernel test robot --- drivers/spi/spi-geni-qcom.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c index 92d88bf85a90..6c7e12b68bf0 100644 --- a/drivers/spi/spi-geni-qcom.c +++ b/drivers/spi/spi-geni-qcom.c @@ -376,15 +376,22 @@ static void setup_fifo_xfer(struct spi_transfer *xfer, len &= TRANS_LEN_MSK; mas->cur_xfer = xfer; + + /* + * Factor out the __iowmb() so that we can use writel_relaxed() for + * both writes below and thus only incur the overhead once even if + * we execute both of them. + */ + __iowmb(); + if (xfer->tx_buf) { m_cmd |= SPI_TX_ONLY; mas->tx_rem_bytes = xfer->len; - writel(len, se->base + SE_SPI_TX_TRANS_LEN); + writel_relaxed(len, se->base + SE_SPI_TX_TRANS_LEN); } - if (xfer->rx_buf) { m_cmd |= SPI_RX_ONLY; - writel(len, se->base + SE_SPI_RX_TRANS_LEN); + writel_relaxed(len, se->base + SE_SPI_RX_TRANS_LEN); mas->rx_rem_bytes = xfer->len; }