From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 required=3.0 tests=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=ham 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 A4FFAC433E1 for ; Wed, 10 Jun 2020 07:45:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83C1B2064C for ; Wed, 10 Jun 2020 07:45:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="WXzfKpRR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726650AbgFJHp2 (ORCPT ); Wed, 10 Jun 2020 03:45:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726627AbgFJHpS (ORCPT ); Wed, 10 Jun 2020 03:45:18 -0400 Received: from mail-pj1-x1041.google.com (mail-pj1-x1041.google.com [IPv6:2607:f8b0:4864:20::1041]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94448C08C5C2 for ; Wed, 10 Jun 2020 00:45:18 -0700 (PDT) Received: by mail-pj1-x1041.google.com with SMTP id jz3so524633pjb.0 for ; Wed, 10 Jun 2020 00:45:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=dSE9dqY0eKEnI3JM3RkevfVx7P9DxAySSIY6zGnKG0k=; b=WXzfKpRRB+NVEcrx1DrXeFn4Zl0QZkDdxU//UBjGNAaCX+JQVGITtK+UGOBEoCUXIK myf8udUAJmwR/9W5QhgROJsAIQ3emSO1B/VNRSPChKLzT2h188lJKbMGa+mE+fk0V55+ 90JALIk6+qnfPhWOvhpZY6kPp/te71ZWukNxu2+zzKmF3sc0xj0+nFd8cYcdWs+/tEgv 0wRxswm3c+jDYZFIahRpQ77uyjSj87kH5OzsVodMBxQRLzcQjv02kH4YlPyAj+0O0QN6 3w4R02ldFEClJoNRIqcy60ArKH74VkIuJiAUUrR1vRbWef5r5f3OosL3rTBUkMktIN7v mAXg== 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; bh=dSE9dqY0eKEnI3JM3RkevfVx7P9DxAySSIY6zGnKG0k=; b=U6IGxIPJsfVvemzzjSmezGA5U68eGeqax74rwskKK6U974lMJY8mYV0RNOaler5uXd gIltQwpxnF+9HS1qvbZfn+7iKnmO+o58T2MXa3cxzhodHvTM1tjw4VpcvoFwIycNCpnY AJOlqYGSPjYO/IApFe5gX14SvjbZwQdLL+NsfVPsMHvaMAlaA6ycI+aRo0M7CPROTb78 6vTYd4gMvjq6ABGZEyJLt+nVWH7g1tsVGaSTY59gWnrG3ntQnw7henbPO0MjvTOePS1r /kNBqWOL/vqcO37+CeLdKJw6FEAysUwU2CDlFVMi6Q7l8JGi9NTpUm3L5BXMmBKsG7KO bwrA== X-Gm-Message-State: AOAM532LCIoem8JwT8P0rxEM295lCwJRLhr0aKJ10wK8+ZUvXpO0xk3I 1/X1hXshJUrCVcBI+2tO1GB2 X-Google-Smtp-Source: ABdhPJwmMllCSLLM48OYqjMqz6MJbQ+nGsnFGVQP7soYwKKPuw84pquM6EqVv45zwjpIhzYLZwIo9A== X-Received: by 2002:a17:90a:8a18:: with SMTP id w24mr1702381pjn.222.1591775118019; Wed, 10 Jun 2020 00:45:18 -0700 (PDT) Received: from Mani-XPS-13-9360.localdomain ([2409:4072:630f:1dba:c41:a14e:6586:388a]) by smtp.gmail.com with ESMTPSA id a20sm11516795pff.147.2020.06.10.00.45.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Jun 2020 00:45:17 -0700 (PDT) From: Manivannan Sadhasivam To: wg@grandegger.com, mkl@pengutronix.de Cc: kernel@martin.sperl.org, linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Manivannan Sadhasivam Subject: [PATCH 5/6] can: mcp25xxfd: Optimize TEF read by avoiding unnecessary SPI transfers Date: Wed, 10 Jun 2020 13:14:41 +0530 Message-Id: <20200610074442.10808-6-manivannan.sadhasivam@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200610074442.10808-1-manivannan.sadhasivam@linaro.org> References: <20200610074442.10808-1-manivannan.sadhasivam@linaro.org> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Martin Sperl We have already enough information to know how many tx-messages have been terminated so that we do not have to query TEF every time if there is anything pending but we can read the tefs blindly. This avoids 1 SPI transfer per TEF read. Signed-off-by: Martin Sperl Signed-off-by: Manivannan Sadhasivam --- .../net/can/spi/mcp25xxfd/mcp25xxfd_can_tx.c | 33 +++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_tx.c b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_tx.c index 5ea1e525e776..6f066cb95844 100644 --- a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_tx.c +++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_tx.c @@ -263,6 +263,13 @@ int mcp25xxfd_can_tx_handle_int_tefif_fifo(struct mcp25xxfd_can_priv *cpriv) MCP25XXFD_CAN_TEFCON_UINC); } +/* reading TEF entries can be made even more efficient by reading + * multiple TEF entries in one go. + * Under the assumption that we have count(TEF) >= count(TX_FIFO) + * we can even release TEFs early (before we read them) + * (and potentially restarting the transmit-queue early aswell) + */ + static int mcp25xxfd_can_tx_handle_int_tefif_conservative(struct mcp25xxfd_can_priv *cpriv) { @@ -293,6 +300,25 @@ mcp25xxfd_can_tx_handle_int_tefif_conservative(struct mcp25xxfd_can_priv *cpriv) return 0; } +static int +mcp25xxfd_can_tx_handle_int_tefif_optimized(struct mcp25xxfd_can_priv *cpriv, + u32 finished) +{ + int i, fifo, ret; + + /* now iterate those */ + for (i = 0, fifo = cpriv->fifos.tx.start; i < cpriv->fifos.tx.count; + i++, fifo++) { + if (finished & BIT(fifo)) { + ret = mcp25xxfd_can_tx_handle_int_tefif_fifo(cpriv); + if (ret) + return ret; + } + } + + return 0; +} + int mcp25xxfd_can_tx_handle_int_tefif(struct mcp25xxfd_can_priv *cpriv) { unsigned long flags; @@ -310,6 +336,13 @@ int mcp25xxfd_can_tx_handle_int_tefif(struct mcp25xxfd_can_priv *cpriv) spin_unlock_irqrestore(&cpriv->fifos.tx_queue->lock, flags); + /* run in optimized mode if possible */ + if (finished) + return mcp25xxfd_can_tx_handle_int_tefif_optimized(cpriv, + finished); + /* otherwise play it safe */ + netdev_warn(cpriv->can.dev, + "Something is wrong - we got a TEF interrupt but we were not able to detect a finished fifo\n"); return mcp25xxfd_can_tx_handle_int_tefif_conservative(cpriv); } -- 2.17.1