From patchwork Tue Jan 3 07:34:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Huacai Chen X-Patchwork-Id: 13087275 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 D0551C3DA7D for ; Tue, 3 Jan 2023 07:34:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232970AbjACHem (ORCPT ); Tue, 3 Jan 2023 02:34:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231239AbjACHel (ORCPT ); Tue, 3 Jan 2023 02:34:41 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8606DEDF for ; Mon, 2 Jan 2023 23:34:40 -0800 (PST) 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 57668B80E14 for ; Tue, 3 Jan 2023 07:34:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6C75C433D2; Tue, 3 Jan 2023 07:34:35 +0000 (UTC) From: Huacai Chen To: Bjorn Helgaas , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= Cc: linux-pci@vger.kernel.org, Jianmin Lv , Xuefeng Li , Huacai Chen , Jiaxun Yang , Huacai Chen Subject: [PATCH 2/2] PCI: Add quirk for LS7A to avoid reboot failure Date: Tue, 3 Jan 2023 15:34:01 +0800 Message-Id: <20230103073401.1256736-3-chenhuacai@loongson.cn> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230103073401.1256736-1-chenhuacai@loongson.cn> References: <20230103073401.1256736-1-chenhuacai@loongson.cn> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org cc27b735ad3a7557 ("PCI/portdrv: Turn off PCIe services during shutdown") causes poweroff/reboot failure on systems with LS7A chipset. We found that if we remove "pci_command &= ~PCI_COMMAND_MASTER" in do_pci_disable _device(), it can work well. The hardware engineer says that the root cause is that CPU is still accessing PCIe devices while poweroff/reboot, and if we disable the Bus Master Bit at this time, the PCIe controller doesn't forward requests to downstream devices, and also does not send TIMEOUT to CPU, which causes CPU wait forever (hardware deadlock). This behavior is a PCIe protocol violation (Bus Master should not be involved in CPU MMIO transactions), and it will be fixed in new revisions of hardware (add timeout mechanism for CPU read request, whether or not Bus Master bit is cleared). On some x86 platforms, radeon/amdgpu devices can cause similar problems [1][2]. Once before I wanted to make a single patch to solve "all of these problems" together, but it seems unreasonable because maybe they are not exactly the same problem. So, this patch add a new function pcie_portdrv_shutdown(), a slight modified copy of pcie_portdrv_remove() dedicated for the shutdown path, and then add a quirk just for LS7A to avoid clearing Bus Master bit in pcie_portdrv_shutdown(). Leave other platforms behave as before. [1] https://bugs.freedesktop.org/show_bug.cgi?id=97980 [2] https://bugs.freedesktop.org/show_bug.cgi?id=98638 Signed-off-by: Huacai Chen --- drivers/pci/controller/pci-loongson.c | 17 +++++++++++++++++ drivers/pci/pcie/portdrv.c | 21 +++++++++++++++++++-- include/linux/pci.h | 1 + 3 files changed, 37 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c index 759ec211c17b..641308ba4126 100644 --- a/drivers/pci/controller/pci-loongson.c +++ b/drivers/pci/controller/pci-loongson.c @@ -93,6 +93,23 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, DEV_PCIE_PORT_2, loongson_mrrs_quirk); +static void loongson_bmaster_quirk(struct pci_dev *pdev) +{ + /* + * Some Loongson PCIe ports will cause CPU deadlock if disable + * the Bus Master bit during poweroff/reboot. + */ + struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus); + + bridge->no_dis_bmaster = 1; +} +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, + DEV_PCIE_PORT_0, loongson_bmaster_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, + DEV_PCIE_PORT_1, loongson_bmaster_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, + DEV_PCIE_PORT_2, loongson_bmaster_quirk); + static void loongson_pci_pin_quirk(struct pci_dev *pdev) { pdev->pin = 1 + (PCI_FUNC(pdev->devfn) & 3); diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c index 2cc2e60bcb39..96f45c444422 100644 --- a/drivers/pci/pcie/portdrv.c +++ b/drivers/pci/pcie/portdrv.c @@ -501,7 +501,6 @@ static void pcie_port_device_remove(struct pci_dev *dev) { device_for_each_child(&dev->dev, NULL, remove_iter); pci_free_irq_vectors(dev); - pci_disable_device(dev); } /** @@ -727,6 +726,24 @@ static void pcie_portdrv_remove(struct pci_dev *dev) } pcie_port_device_remove(dev); + + pci_disable_device(dev); +} + +static void pcie_portdrv_shutdown(struct pci_dev *dev) +{ + struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus); + + if (pci_bridge_d3_possible(dev)) { + pm_runtime_forbid(&dev->dev); + pm_runtime_get_noresume(&dev->dev); + pm_runtime_dont_use_autosuspend(&dev->dev); + } + + pcie_port_device_remove(dev); + + if (!bridge->no_dis_bmaster) + pci_disable_device(dev); } static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev, @@ -777,7 +794,7 @@ static struct pci_driver pcie_portdriver = { .probe = pcie_portdrv_probe, .remove = pcie_portdrv_remove, - .shutdown = pcie_portdrv_remove, + .shutdown = pcie_portdrv_shutdown, .err_handler = &pcie_portdrv_err_handler, diff --git a/include/linux/pci.h b/include/linux/pci.h index 3df2049ec4a8..a64dbcb89231 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -573,6 +573,7 @@ struct pci_host_bridge { unsigned int ignore_reset_delay:1; /* For entire hierarchy */ unsigned int no_ext_tags:1; /* No Extended Tags */ unsigned int no_inc_mrrs:1; /* No Increase MRRS */ + unsigned int no_dis_bmaster:1; /* No Disable Bus Master */ unsigned int native_aer:1; /* OS may use PCIe AER */ unsigned int native_pcie_hotplug:1; /* OS may use PCIe hotplug */ unsigned int native_shpc_hotplug:1; /* OS may use SHPC hotplug */