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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 40616C76192 for ; Thu, 18 Jul 2019 03:09:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1A0C721848 for ; Thu, 18 Jul 2019 03:09:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563419374; bh=S/h8bMj9dYlzLDIQkq5FX3kIwrthWQmwTA+B6FKzt/4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=m+JgqKrgWEcki726Mi5mObKFReSTXmJyYL5Qh6gRLJNaeBFt1GeAolnb4u7mj+h0i MclyhFJ6IpcWjdGSldFDYOr7DU2nD1006qhgx0bDmSdygBC8VICpmsgLLegrLYi2mG DW7EXJFcGEtT61HpPJLDIVCsPXPF33pSPpkaRNjg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391005AbfGRDJd (ORCPT ); Wed, 17 Jul 2019 23:09:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:42118 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390999AbfGRDJc (ORCPT ); Wed, 17 Jul 2019 23:09:32 -0400 Received: from localhost (115.42.148.210.bf.2iij.net [210.148.42.115]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C1AAB20818; Thu, 18 Jul 2019 03:09:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563419371; bh=S/h8bMj9dYlzLDIQkq5FX3kIwrthWQmwTA+B6FKzt/4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k+d/x0jaAtvS+E/PMEG2c24YeOU7XlKAvJrgc5+JOMs44nUwoJVgKVH3b+hTSddbJ buBZn9ph8FvqzzVqSXIeh+yOHmqK1AAmi6uK0AHuUia0HHxb+Fd3mxJFwOkCLzppxf 1V0tWsPxVcAVkZThahKzCMIZOpPbbnDQ4cRdcKik= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eugen Hristev , Ludovic Desroches , Marc Kleine-Budde , Sasha Levin Subject: [PATCH 4.14 19/80] can: m_can: implement errata "Needless activation of MRAF irq" Date: Thu, 18 Jul 2019 12:01:10 +0900 Message-Id: <20190718030100.325995106@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190718030058.615992480@linuxfoundation.org> References: <20190718030058.615992480@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit 3e82f2f34c930a2a0a9e69fdc2de2f2f1388b442 ] During frame reception while the MCAN is in Error Passive state and the Receive Error Counter has thevalue MCAN_ECR.REC = 127, it may happen that MCAN_IR.MRAF is set although there was no Message RAM access failure. If MCAN_IR.MRAF is enabled, an interrupt to the Host CPU is generated. Work around: The Message RAM Access Failure interrupt routine needs to check whether MCAN_ECR.RP = '1' and MCAN_ECR.REC = '127'. In this case, reset MCAN_IR.MRAF. No further action is required. This affects versions older than 3.2.0 Errata explained on Sama5d2 SoC which includes this hardware block: http://ww1.microchip.com/downloads/en/DeviceDoc/SAMA5D2-Family-Silicon-Errata-and-Data-Sheet-Clarification-DS80000803B.pdf chapter 6.2 Reproducibility: If 2 devices with m_can are connected back to back, configuring different bitrate on them will lead to interrupt storm on the receiving side, with error "Message RAM access failure occurred". Another way is to have a bad hardware connection. Bad wire connection can lead to this issue as well. This patch fixes the issue according to provided workaround. Signed-off-by: Eugen Hristev Reviewed-by: Ludovic Desroches Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin --- drivers/net/can/m_can/m_can.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index d3ce904e929e..ebad93ac8f11 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -818,6 +818,27 @@ static int m_can_poll(struct napi_struct *napi, int quota) if (!irqstatus) goto end; + /* Errata workaround for issue "Needless activation of MRAF irq" + * During frame reception while the MCAN is in Error Passive state + * and the Receive Error Counter has the value MCAN_ECR.REC = 127, + * it may happen that MCAN_IR.MRAF is set although there was no + * Message RAM access failure. + * If MCAN_IR.MRAF is enabled, an interrupt to the Host CPU is generated + * The Message RAM Access Failure interrupt routine needs to check + * whether MCAN_ECR.RP = ’1’ and MCAN_ECR.REC = 127. + * In this case, reset MCAN_IR.MRAF. No further action is required. + */ + if ((priv->version <= 31) && (irqstatus & IR_MRAF) && + (m_can_read(priv, M_CAN_ECR) & ECR_RP)) { + struct can_berr_counter bec; + + __m_can_get_berr_counter(dev, &bec); + if (bec.rxerr == 127) { + m_can_write(priv, M_CAN_IR, IR_MRAF); + irqstatus &= ~IR_MRAF; + } + } + psr = m_can_read(priv, M_CAN_PSR); if (irqstatus & IR_ERR_STATE) work_done += m_can_handle_state_errors(dev, psr); -- 2.20.1