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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 162E4C43334 for ; Fri, 17 Jun 2022 07:48:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380242AbiFQHst (ORCPT ); Fri, 17 Jun 2022 03:48:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346603AbiFQHst (ORCPT ); Fri, 17 Jun 2022 03:48:49 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9CAE674F7 for ; Fri, 17 Jun 2022 00:48:47 -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 A6E59B827A2 for ; Fri, 17 Jun 2022 07:48:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 103E3C3411B; Fri, 17 Jun 2022 07:48:42 +0000 (UTC) From: Huacai Chen To: Bjorn Helgaas , Lorenzo Pieralisi , Rob Herring , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= Cc: linux-pci@vger.kernel.org, Jianmin Lv , Xuefeng Li , Huacai Chen , Jiaxun Yang , Huacai Chen Subject: [PATCH V14 6/7] PCI: Add quirk for LS7A to avoid reboot failure Date: Fri, 17 Jun 2022 15:43:29 +0800 Message-Id: <20220617074330.12605-7-chenhuacai@loongson.cn> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220617074330.12605-1-chenhuacai@loongson.cn> References: <20220617074330.12605-1-chenhuacai@loongson.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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_core.c | 1 - drivers/pci/pcie/portdrv_pci.c | 20 +++++++++++++++++++- include/linux/pci.h | 1 + 4 files changed, 37 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c index 62ac91b2a5c5..6d7276debcfd 100644 --- a/drivers/pci/controller/pci-loongson.c +++ b/drivers/pci/controller/pci-loongson.c @@ -85,6 +85,23 @@ 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 struct loongson_pci *pci_bus_to_loongson_pci(struct pci_bus *bus) { struct pci_config_window *cfg; diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c index 604feeb84ee4..ee3d654dcbb4 100644 --- a/drivers/pci/pcie/portdrv_core.c +++ b/drivers/pci/pcie/portdrv_core.c @@ -493,7 +493,6 @@ 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); } /** diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index 7f8788a970ae..f821f916d020 100644 --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -148,6 +148,24 @@ 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, @@ -198,7 +216,7 @@ 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 a9211074add6..0f0908679074 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -570,6 +570,7 @@ 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 */ -- 2.27.0