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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 782EDC433E6 for ; Mon, 1 Mar 2021 22:29:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF40A600EF for ; Mon, 1 Mar 2021 22:29:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244817AbhCAW2J (ORCPT ); Mon, 1 Mar 2021 17:28:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:56326 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238596AbhCAReP (ORCPT ); Mon, 1 Mar 2021 12:34:15 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0252B64FB5; Mon, 1 Mar 2021 16:53:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614617631; bh=zALidLivyhGJzurLP3RgXTjQv++DahGtOpqvB+1aiRQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tYJHks0ErVMJcYICq2izSoA532+feRhvBceCGOQqUBUaMqO4YJxSVk+1Qe4j9nBhe P+C9q7jVRU3Z+zVMV10KYrje0TACRwIQLx0jS+QmwLZ9jvh6Rqe/7xLHqIh2h0sRxI 4fkfr9/vdUtqwIW766XwutgNS7wkXdwd755ZwPXo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ferry Toth , Andy Shevchenko , Vinod Koul , Sasha Levin Subject: [PATCH 5.4 142/340] dmaengine: hsu: disable spurious interrupt Date: Mon, 1 Mar 2021 17:11:26 +0100 Message-Id: <20210301161055.305736328@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161048.294656001@linuxfoundation.org> References: <20210301161048.294656001@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ferry Toth [ Upstream commit 035b73b2b3b2e074a56489a7bf84b6a8012c0e0d ] On Intel Tangier B0 and Anniedale the interrupt line, disregarding to have different numbers, is shared between HSU DMA and UART IPs. Thus on such SoCs we are expecting that IRQ handler is called in UART driver only. hsu_pci_irq was handling the spurious interrupt from HSU DMA by returning immediately. This wastes CPU time and since HSU DMA and HSU UART interrupt occur simultaneously they race to be handled causing delay to the HSU UART interrupt handling. Fix this by disabling the interrupt entirely. Fixes: 4831e0d9054c ("serial: 8250_mid: handle interrupt correctly in DMA case") Signed-off-by: Ferry Toth Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20210112223749.97036-1-ftoth@exalondelft.nl Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin --- drivers/dma/hsu/pci.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/drivers/dma/hsu/pci.c b/drivers/dma/hsu/pci.c index 07cc7320a614f..9045a6f7f5893 100644 --- a/drivers/dma/hsu/pci.c +++ b/drivers/dma/hsu/pci.c @@ -26,22 +26,12 @@ static irqreturn_t hsu_pci_irq(int irq, void *dev) { struct hsu_dma_chip *chip = dev; - struct pci_dev *pdev = to_pci_dev(chip->dev); u32 dmaisr; u32 status; unsigned short i; int ret = 0; int err; - /* - * On Intel Tangier B0 and Anniedale the interrupt line, disregarding - * to have different numbers, is shared between HSU DMA and UART IPs. - * Thus on such SoCs we are expecting that IRQ handler is called in - * UART driver only. - */ - if (pdev->device == PCI_DEVICE_ID_INTEL_MRFLD_HSU_DMA) - return IRQ_HANDLED; - dmaisr = readl(chip->regs + HSU_PCI_DMAISR); for (i = 0; i < chip->hsu->nr_channels; i++) { if (dmaisr & 0x1) { @@ -105,6 +95,17 @@ static int hsu_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) if (ret) goto err_register_irq; + /* + * On Intel Tangier B0 and Anniedale the interrupt line, disregarding + * to have different numbers, is shared between HSU DMA and UART IPs. + * Thus on such SoCs we are expecting that IRQ handler is called in + * UART driver only. Instead of handling the spurious interrupt + * from HSU DMA here and waste CPU time and delay HSU UART interrupt + * handling, disable the interrupt entirely. + */ + if (pdev->device == PCI_DEVICE_ID_INTEL_MRFLD_HSU_DMA) + disable_irq_nosync(chip->irq); + pci_set_drvdata(pdev, chip); return 0; -- 2.27.0