From patchwork Wed Apr 19 22:33:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Judith Mendez X-Patchwork-Id: 13217591 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7E570C6FD18 for ; Wed, 19 Apr 2023 22:34:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:CC :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=htJns63WxWE30Vop8gZIy+sY77HjVjPQf1K2IKUmy+w=; b=xPvf2aHG4ydVVU BtkDs4IfuW8OG8Si5uwm6t1dPUJwYo4d0QaD6nh7bUzdd7KYJsG5FL1UBSLSkpy1ACBGYnwyzXfDZ haGMx7I6Gn4qKdd/fBA80vHqHnYfqLtgkTqVaR/ewmKlIFZ/mTT8wQpREgwPr6k14RY4zQipsbfip 0CF6icvfTTQ4aSpexbq7LfqojfkjHVWSGOCq5PUw54dTNgg6ZAhuje4wMGUUIGHILncpeGI79usT5 RFIuKcG8+sL4E0Zb8+bNZSlt2rKVDWDKM9Fntk887ZrCM3G+kS8owxMVbJFcEAxXOK/ZDeOb6fWEJ 1uUmeqsU0ZaDpc/eu7IA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1ppGNB-006VrD-1Y; Wed, 19 Apr 2023 22:33:57 +0000 Received: from fllv0016.ext.ti.com ([198.47.19.142]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1ppGMz-006Voc-2H for linux-arm-kernel@lists.infradead.org; Wed, 19 Apr 2023 22:33:48 +0000 Received: from fllv0035.itg.ti.com ([10.64.41.0]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 33JMXOTX088934; Wed, 19 Apr 2023 17:33:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1681943604; bh=qSHxA2JuD9iVuHUIsjmZUVoAD15PhbOU9uLN9c3n25g=; h=From:To:CC:Subject:Date; b=ng6lnJQqlOjY+0biJJDivbVoW2wOfHYT26DJcfg/sbVkwss1AhUTmpuZeQ/i1bqJV 3RslBeMDaY2fu+ZDgKtF4j3fFwvsvgocK54/dEP10NUBOM+afMoWBhoPgGISYj+4zg 4Gws3A1rawdVHqtXXQI0S+mIKcAqbZSHgOuMHYAI= Received: from DLEE101.ent.ti.com (dlee101.ent.ti.com [157.170.170.31]) by fllv0035.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 33JMXOlh059400 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 19 Apr 2023 17:33:24 -0500 Received: from DLEE107.ent.ti.com (157.170.170.37) by DLEE101.ent.ti.com (157.170.170.31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.16; Wed, 19 Apr 2023 17:33:24 -0500 Received: from lelv0327.itg.ti.com (10.180.67.183) by DLEE107.ent.ti.com (157.170.170.37) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.16 via Frontend Transport; Wed, 19 Apr 2023 17:33:23 -0500 Received: from a0498204.dal.design.ti.com (ileaxei01-snat2.itg.ti.com [10.180.69.6]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id 33JMXNLV015736; Wed, 19 Apr 2023 17:33:23 -0500 From: Judith Mendez To: Chandrasekar Ramakrishnan , Wolfgang Grandegger , Marc Kleine-Budde CC: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Schuyler Patton , Nishanth Menon , Vignesh Raghavendra , Tero Kristo , Rob Herring , Krzysztof Kozlowski , Oliver Hartkopp , Judith Mendez , , , , , Subject: [PATCH 0/4] Enable multiple MCAN on AM62x Date: Wed, 19 Apr 2023 17:33:19 -0500 Message-ID: <20230419223323.20384-1-jm@ti.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230419_153345_841460_670293B6 X-CRM114-Status: GOOD ( 16.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On AM62x there is one MCAN in MAIN domain and two in MCU domain. The MCANs in MCU domain were not enabled since there is no hardware interrupt routed to A53 GIC interrupt controller. Therefore A53 Linux cannot be interrupted by MCU MCANs. This solution instantiates a hrtimer with 1 ms polling interval for a MCAN when there is no hardware interrupt. This hrtimer generates a recurring software interrupt which allows to call the isr. The isr will check if there is pending transaction by reading a register and proceed normally if there is. On AM62x this series enables two MCU MCAN which will use the hrtimer implementation. MCANs with hardware interrupt routed to A53 Linux will continue to use the hardware interrupt as expected. Timer polling method was tested on both classic CAN and CAN-FD at 125 KBPS, 250 KBPS, 1 MBPS and 2.5 MBPS with 4 MBPS bitrate switching. Letency and CPU load benchmarks were tested on 3x MCAN on AM62x. 1 MBPS timer polling interval is the better timer polling interval since it has comparable latency to hardware interrupt with the worse case being 1ms + CAN frame propagation time and CPU load is not substantial. Latency can be improved further with less than 1 ms polling intervals, howerver it is at the cost of CPU usage since CPU load increases at 0.5 ms and lower polling periods than 1ms. Note that in terms of power, enabling MCU MCANs with timer-polling implementation might have negative impact since we will have to wake up every 1 ms whether there are CAN packets pending in the RX FIFO or not. This might prevent the CPU from entering into deeper idle states for extended periods of time. This patch series depends on 'Enable CAN PHY transceiver driver': https://lore.kernel.org/lkml/775ec9ce-7668-429c-a977-6c8995968d6e@app.fastmail.com/T/ Previously sent an RFC: https://lore.kernel.org/linux-can/52a37e51-4143-9017-42ee-8d17c67028e3@ti.com/T/#t Judith Mendez (4): can: m_can: Add hrtimer to generate software interrupt dt-bindings: net: can: Make interrupt attributes optional for MCAN arm64: dts: ti: Add AM62x MCAN MAIN domain transceiver overlay arm64: dts: ti: Enable MCU MCANs for AM62x .../bindings/net/can/bosch,m_can.yaml | 2 - arch/arm64/boot/dts/ti/Makefile | 2 + arch/arm64/boot/dts/ti/k3-am62-mcu.dtsi | 24 ++++++++ .../boot/dts/ti/k3-am625-sk-mcan-main.dtso | 35 ++++++++++++ .../boot/dts/ti/k3-am625-sk-mcan-mcu.dtso | 55 +++++++++++++++++++ drivers/net/can/m_can/m_can.c | 30 +++++++++- drivers/net/can/m_can/m_can.h | 3 + drivers/net/can/m_can/m_can_platform.c | 13 ++++- 8 files changed, 158 insertions(+), 6 deletions(-) create mode 100644 arch/arm64/boot/dts/ti/k3-am625-sk-mcan-main.dtso create mode 100644 arch/arm64/boot/dts/ti/k3-am625-sk-mcan-mcu.dtso