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=-18.9 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, URIBL_BLOCKED,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 0CA17C4743E for ; Tue, 8 Jun 2021 08:04:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E796161285 for ; Tue, 8 Jun 2021 08:04:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230355AbhFHIGM (ORCPT ); Tue, 8 Jun 2021 04:06:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:57461 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230330AbhFHIGJ (ORCPT ); Tue, 8 Jun 2021 04:06:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623139456; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=eRLfIlExKhLKW3ohxS3QmcrC8PB6Pwunoa93O+xqbII=; b=D2zd8bJgok0SvLPT69Bf+0IYBaLtMG6ggeUwwDn2wZJxhsvbhBIDhdAQ/TgHYEsehNwdyw +kJB5lyO7j1OVejSP+jJ5eZ9GX+kB6st2WSh1/HYb3M46Z+lxxLiPavtkRmtT0wRSNLQIT cl53VMNmAcw2XFntLyuX3flJnLnp5FU= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-101-K7GpG2QYPhmtIJAss_WOjw-1; Tue, 08 Jun 2021 04:04:15 -0400 X-MC-Unique: K7GpG2QYPhmtIJAss_WOjw-1 Received: by mail-wr1-f71.google.com with SMTP id g14-20020a5d698e0000b0290117735bd4d3so8971865wru.13 for ; Tue, 08 Jun 2021 01:04:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=eRLfIlExKhLKW3ohxS3QmcrC8PB6Pwunoa93O+xqbII=; b=Hb0guMHzbYG8iZvYW/oPCqUxhor37NoK+UGh7LM8Z0qJZRfsQMk2JsiXcj2xPxj0fW NsLEK1SHapVSF9P0zwvoaYi/SjbxiESbDAx1X9CGm8QjWPHQH17is78U0GyStM2Q3VXh rmtAh7qWrBemGvIneb1V6NbfkuiD5ypTouK7VkKipXxtvv1Kurbj6z5xmVCIZHtJKrfP AEt1TNuNmJzTU+SNLfz0KkQSLE3iBmEzagPcMG0AEp3qxxbz0aT18dw2f2rJKqxivkbD kNPKr2BTjlEya+wwpFeQhsmR4ZeeUawC066BFE+3dfB/w2rcarpL1OObTYcLerRZxHXa DmxA== X-Gm-Message-State: AOAM5331z4eMaNjTQ28KoQPJF8z+4CQXBYh9GnQqx9flRk6qMu0uebkx TLp2xXSmU/V3hF269xAZ56WZbUv8g3rn273ihuldt2vtkbTez1na4IphyCnQFvkJcfD9oGsJulz sTQD/vxBq2xENcSuuQT7xyEEJI/cpagVJRz8qmPKRR38KTiSowqO+BqRV9yNUbNq4EhorR+SX5W s= X-Received: by 2002:a5d:5983:: with SMTP id n3mr8801737wri.241.1623139453819; Tue, 08 Jun 2021 01:04:13 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwMZdm0lOV6CTzcaqjiMsts4ZrMuE5GRipe8Uouaz7yC1zHJCdwRHLBh8j5A6Gyo/laf6JPcw== X-Received: by 2002:a5d:5983:: with SMTP id n3mr8801701wri.241.1623139453534; Tue, 08 Jun 2021 01:04:13 -0700 (PDT) Received: from minerva.redhat.com ([92.176.231.106]) by smtp.gmail.com with ESMTPSA id q11sm18515680wrx.80.2021.06.08.01.04.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Jun 2021 01:04:13 -0700 (PDT) From: Javier Martinez Canillas To: linux-kernel@vger.kernel.org Cc: Javier Martinez Canillas , Peter Robinson , Shawn Lin , Bjorn Helgaas , Heiko Stuebner , Lorenzo Pieralisi , Rob Herring , linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-rockchip@lists.infradead.org Subject: [PATCH v2] PCI: rockchip: Avoid accessing PCIe registers with clocks gated Date: Tue, 8 Jun 2021 10:04:09 +0200 Message-Id: <20210608080409.1729276-1-javierm@redhat.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org IRQ handlers that are registered for shared interrupts can be called at any time after have been registered using the request_irq() function. It's up to drivers to ensure that's always safe for these to be called. Both the "pcie-sys" and "pcie-client" interrupts are shared, but since their handlers are registered very early in the probe function, an error later can lead to these handlers being executed before all the required resources have been properly setup. For example, the rockchip_pcie_read() function used by these IRQ handlers expects that some PCIe clocks will already be enabled, otherwise trying to access the PCIe registers causes the read to hang and never return. The CONFIG_DEBUG_SHIRQ option tests if drivers are able to cope with their shared interrupt handlers being called, by generating a spurious interrupt just before a shared interrupt handler is unregistered. But this means that if the option is enabled, any error in the probe path of this driver could lead to one of the IRQ handlers to be executed. In a rockpro64 board, the following sequence of events happens: 1) "pcie-sys" IRQ is requested and its handler registered. 2) "pcie-client" IRQ is requested and its handler registered. 3) probe later fails due readl_poll_timeout() returning a timeout. 4) the "pcie-sys" IRQ is unregistered. 5) CONFIG_DEBUG_SHIRQ triggers a spurious interrupt. 6) "pcie-client" IRQ handler is called for this spurious interrupt. 7) IRQ handler tries to read PCIE_CLIENT_INT_STATUS with clocks gated. 8) the machine hangs because rockchip_pcie_read() call never returns. To avoid cases like this, the handlers don't have to be registered until very late in the probe function, once all the resources have been setup. So let's just move all the IRQ init before the pci_host_probe() call, that will prevent issues like this and seems to be the correct thing to do too. Reported-by: Peter Robinson Signed-off-by: Javier Martinez Canillas Acked-by: Shawn Lin --- Changes in v2: - Add missing word in the commit message. - Include Shawn Lin's Acked-by tag. drivers/pci/controller/pcie-rockchip-host.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c index f1d08a1b159..78d04ac29cd 100644 --- a/drivers/pci/controller/pcie-rockchip-host.c +++ b/drivers/pci/controller/pcie-rockchip-host.c @@ -592,10 +592,6 @@ static int rockchip_pcie_parse_host_dt(struct rockchip_pcie *rockchip) if (err) return err; - err = rockchip_pcie_setup_irq(rockchip); - if (err) - return err; - rockchip->vpcie12v = devm_regulator_get_optional(dev, "vpcie12v"); if (IS_ERR(rockchip->vpcie12v)) { if (PTR_ERR(rockchip->vpcie12v) != -ENODEV) @@ -973,8 +969,6 @@ static int rockchip_pcie_probe(struct platform_device *pdev) if (err) goto err_vpcie; - rockchip_pcie_enable_interrupts(rockchip); - err = rockchip_pcie_init_irq_domain(rockchip); if (err < 0) goto err_deinit_port; @@ -992,6 +986,12 @@ static int rockchip_pcie_probe(struct platform_device *pdev) bridge->sysdata = rockchip; bridge->ops = &rockchip_pcie_ops; + err = rockchip_pcie_setup_irq(rockchip); + if (err) + goto err_remove_irq_domain; + + rockchip_pcie_enable_interrupts(rockchip); + err = pci_host_probe(bridge); if (err < 0) goto err_remove_irq_domain; -- 2.31.1