From patchwork Thu Dec 21 11:38:44 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honghui Zhang X-Patchwork-Id: 851870 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3z2V6c220qz9s7F for ; Thu, 21 Dec 2017 22:39:36 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752816AbdLULjI (ORCPT ); Thu, 21 Dec 2017 06:39:08 -0500 Received: from mailgw02.mediatek.com ([210.61.82.184]:37719 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751867AbdLULjE (ORCPT ); Thu, 21 Dec 2017 06:39:04 -0500 X-UUID: a763e491aa144c8fa31a78b12787ed6d-20171221 Received: from mtkexhb02.mediatek.inc [(172.21.101.103)] by mailgw02.mediatek.com (envelope-from ) (mhqrelay.mediatek.com ESMTP with TLS) with ESMTP id 330635135; Thu, 21 Dec 2017 19:38:59 +0800 Received: from MTKCAS06.mediatek.inc (172.21.101.30) by mtkmbs08n1.mediatek.inc (172.21.101.55) with Microsoft SMTP Server (TLS) id 15.0.1210.3; Thu, 21 Dec 2017 19:38:57 +0800 Received: from localhost.localdomain (10.17.3.153) by MTKCAS06.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1210.3 via Frontend Transport; Thu, 21 Dec 2017 19:38:56 +0800 From: To: , , , , , , , , , , CC: , , , , , , Subject: [PATCH v3 1/2] PCI: mediatek: Clear IRQ status after IRQ dispatched to avoid reentry Date: Thu, 21 Dec 2017 19:38:44 +0800 Message-ID: <1513856325-28813-2-git-send-email-honghui.zhang@mediatek.com> X-Mailer: git-send-email 2.6.4 In-Reply-To: <1513856325-28813-1-git-send-email-honghui.zhang@mediatek.com> References: <1513856325-28813-1-git-send-email-honghui.zhang@mediatek.com> MIME-Version: 1.0 X-MTK: N Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Honghui Zhang There maybe a same IRQ reentry scenario after IRQ received in current IRQ handle flow: EP device PCIe host driver EP driver 1. issue an IRQ 2. received IRQ 3. clear IRQ status 4. dispatch IRQ 5. clear IRQ source The IRQ status was not successfully cleared at step 2 since the IRQ source was not cleared yet. So the PCIe host driver may receive the same IRQ after step 5. Then there's an IRQ reentry occurred. Even worse, if the reentry IRQ was not an IRQ that EP driver expected, it may not handle the IRQ. Then we may run into the infinite loop from step 2 to step 4. Clear the IRQ status after IRQ have been dispatched to avoid the IRQ reentry. This patch also fix another INTx IRQ issue by initialize the iterate before the loop. If an INTx IRQ re-occurred while we are dispatching the INTx IRQ, then iterate may start from PCI_NUM_INTX + INTX_SHIFT instead of INTX_SHIFT for the second time entering the for_each_set_bit_from() loop. Signed-off-by: Honghui Zhang Acked-by: Ryder Lee --- drivers/pci/host/pcie-mediatek.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/pci/host/pcie-mediatek.c b/drivers/pci/host/pcie-mediatek.c index db93efd..fc29a9a 100644 --- a/drivers/pci/host/pcie-mediatek.c +++ b/drivers/pci/host/pcie-mediatek.c @@ -601,15 +601,16 @@ static irqreturn_t mtk_pcie_intr_handler(int irq, void *data) struct mtk_pcie_port *port = (struct mtk_pcie_port *)data; unsigned long status; u32 virq; - u32 bit = INTX_SHIFT; + u32 bit; while ((status = readl(port->base + PCIE_INT_STATUS)) & INTX_MASK) { + bit = INTX_SHIFT; for_each_set_bit_from(bit, &status, PCI_NUM_INTX + INTX_SHIFT) { - /* Clear the INTx */ - writel(1 << bit, port->base + PCIE_INT_STATUS); virq = irq_find_mapping(port->irq_domain, bit - INTX_SHIFT); generic_handle_irq(virq); + /* Clear the INTx */ + writel(1 << bit, port->base + PCIE_INT_STATUS); } } @@ -619,10 +620,10 @@ static irqreturn_t mtk_pcie_intr_handler(int irq, void *data) while ((imsi_status = readl(port->base + PCIE_IMSI_STATUS))) { for_each_set_bit(bit, &imsi_status, MTK_MSI_IRQS_NUM) { - /* Clear the MSI */ - writel(1 << bit, port->base + PCIE_IMSI_STATUS); virq = irq_find_mapping(port->msi_domain, bit); generic_handle_irq(virq); + /* Clear the MSI */ + writel(1 << bit, port->base + PCIE_IMSI_STATUS); } } /* Clear MSI interrupt status */