From patchwork Tue Aug 2 12:38:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Pali_Roh=C3=A1r?= X-Patchwork-Id: 12934615 X-Patchwork-Delegate: lorenzo.pieralisi@arm.com 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA71EC00140 for ; Tue, 2 Aug 2022 12:39:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236081AbiHBMjT (ORCPT ); Tue, 2 Aug 2022 08:39:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233181AbiHBMjS (ORCPT ); Tue, 2 Aug 2022 08:39:18 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C64E1FCDD; Tue, 2 Aug 2022 05:39:17 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2A166B81EF7; Tue, 2 Aug 2022 12:39:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B945C433D6; Tue, 2 Aug 2022 12:39:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659443954; bh=czjqSbGtpIYmswV/Rh3E0u4EPRbeo8kro8V9wiWdp5k=; h=From:To:Cc:Subject:Date:From; b=GzvWjGshRogL5da+jhHTw7kSXC/ItA43Eelv5Fg5fhWHujny4CORKbWe3G8cl6dmv rWDUl1TZNX6WUGK3WmTrBjdB0J0lGa/AWWNQbJsBqmgHDiAMb+ULVxWfmtDnZO/NhY mONuZthsFIplbOHBEv6BspaNrSEQTKlZ8YXYJ+xDGL54Bmzg8tzaEpWzPFnf3cS8HH ykbPOMNvbi6SXS5gkp/kv/9cembG4Nk0MpWeFo3ghK6CDKZsffLJM8T7yqTmuRPLll oJMxIGznROtPB7+wi3zpKTh9xPVZCFnPG60O7he/CRWBUUhjNE5eioQjhGudIdGDAV o1uy/9X1hpKAQ== Received: by pali.im (Postfix) id F224DF81; Tue, 2 Aug 2022 14:39:10 +0200 (CEST) From: =?utf-8?q?Pali_Roh=C3=A1r?= To: Thomas Petazzoni , Lorenzo Pieralisi , Bjorn Helgaas , Elad Nachman Cc: =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , Rob Herring , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Gregory Clement , =?utf-8?q?Marek_Beh=C3=BAn?= , Remi Pommarel , Xogium , Tomasz Maciej Nowak Subject: [PATCH v2] PCI: aardvark: Implement workaround for PCIe Completion Timeout Date: Tue, 2 Aug 2022 14:38:16 +0200 Message-Id: <20220802123816.21817-1-pali@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Marvell Armada 3700 Functional Errata, Guidelines, and Restrictions document describes in erratum 3.12 PCIe Completion Timeout (Ref #: 251), that PCIe IP does not support a strong-ordered model for inbound posted vs. outbound completion. As a workaround for this erratum, DIS_ORD_CHK flag in Debug Mux Control register must be set. It disables the ordering check in the core between Completions and Posted requests received from the link. Marvell also suggests to do full memory barrier at the beginning of aardvark summary interrupt handler before calling interrupt handlers of endpoint drivers in order to minimize the risk for the race condition documented in the Erratum between the DMA done status reading and the completion of writing to the host memory. More details about this issue and suggested workarounds are in discussion: https://lore.kernel.org/linux-pci/BN9PR18MB425154FE5019DCAF2028A1D5DB8D9@BN9PR18MB4251.namprd18.prod.outlook.com/t/#u It was reported that enabling this workaround fixes instability issues and "Unhandled fault" errors when using 60 GHz WiFi 802.11ad card with Qualcomm QCA6335 chip under significant load which were caused by interrupt status stuck in the outbound CMPLT queue traced back to this erratum. This workaround fixes also kernel panic triggered after some minutes of usage 5 GHz WiFi 802.11ax card with Mediatek MT7915 chip: Internal error: synchronous external abort: 96000210 [#1] SMP Kernel panic - not syncing: Fatal exception in interrupt Signed-off-by: Thomas Petazzoni Signed-off-by: Pali Rohár Fixes: 8c39d710363c ("PCI: aardvark: Add Aardvark PCI host controller driver") Cc: stable@vger.kernel.org Reviewed-by: Elad Nachman --- drivers/pci/controller/pci-aardvark.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index 060936ef01fe..3ae8a85ec72e 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -210,6 +210,8 @@ enum { }; #define VENDOR_ID_REG (LMI_BASE_ADDR + 0x44) +#define DEBUG_MUX_CTRL_REG (LMI_BASE_ADDR + 0x208) +#define DIS_ORD_CHK BIT(30) /* PCIe core controller registers */ #define CTRL_CORE_BASE_ADDR 0x18000 @@ -558,6 +560,11 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie) PCIE_CORE_CTRL2_TD_ENABLE; advk_writel(pcie, reg, PCIE_CORE_CTRL2_REG); + /* Disable ordering checks, workaround for erratum 3.12 "PCIe completion timeout" */ + reg = advk_readl(pcie, DEBUG_MUX_CTRL_REG); + reg |= DIS_ORD_CHK; + advk_writel(pcie, reg, DEBUG_MUX_CTRL_REG); + /* Set lane X1 */ reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG); reg &= ~LANE_CNT_MSK; @@ -1581,6 +1588,9 @@ static irqreturn_t advk_pcie_irq_handler(int irq, void *arg) struct advk_pcie *pcie = arg; u32 status; + /* Full memory barrier (ARM dsb sy), workaround for erratum 3.12 "PCIe completion timeout" */ + mb(); + status = advk_readl(pcie, HOST_CTRL_INT_STATUS_REG); if (!(status & PCIE_IRQ_CORE_INT)) return IRQ_NONE;