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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 85F71C33CB6 for ; Thu, 16 Jan 2020 23:25:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5AB6D206D9 for ; Thu, 16 Jan 2020 23:25:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579217141; bh=Fo+u8jCqjvVU+GH5Zba5qwmB33L77o4+BSksY3M92EQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aXShSK7kuhWzVD4Xhe0X96S1AYmRZxY2aXk+yCqrpRaNy6J5aZAYQNu5O/OHBc6ZT /PKCvgXfzqcqnYS/2KrE9/7nHhP17A5alkFijpWZx/O0fVIqIApoZLEPRtF+En1HnV yv3+L+0qE5yzGhtiWgE15Z4FYRQBga+VZ8JTP1PE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729592AbgAPXZk (ORCPT ); Thu, 16 Jan 2020 18:25:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:54954 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387532AbgAPXZV (ORCPT ); Thu, 16 Jan 2020 18:25:21 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D06C02075B; Thu, 16 Jan 2020 23:25:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579217120; bh=Fo+u8jCqjvVU+GH5Zba5qwmB33L77o4+BSksY3M92EQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m4NbAfPKekBV2Uac/yLndh0lpKEFmzcv4LCMbMKIarsdhQIBMhYNc8gOrQ8Qgo9mb 6WXb6GzoBEBisJDhmLrldh6Nxfa4pb9jiXkvFxT2xDrlWCI4wDG3SX3LV6EpgpFUo1 ZrhaE3apJD5xSdPkA/54Sb9ygWCgYOnia1OrKq9I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oliver OHalloran , Michael Ellerman Subject: [PATCH 5.4 139/203] powerpc/powernv: Disable native PCIe port management Date: Fri, 17 Jan 2020 00:17:36 +0100 Message-Id: <20200116231757.169670122@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200116231745.218684830@linuxfoundation.org> References: <20200116231745.218684830@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oliver O'Halloran commit 9d72dcef891030545f39ad386a30cf91df517fb2 upstream. On PowerNV the PCIe topology is (currently) managed by the powernv platform code in Linux in cooperation with the platform firmware. Linux's native PCIe port service drivers operate independently of both and this can cause problems. The main issue is that the portbus driver will conflict with the platform specific hotplug driver (pnv_php) over ownership of the MSI used to notify the host when a hotplug event occurs. The portbus driver claims this MSI on behalf of the individual port services because the same interrupt is used for hotplug events, PMEs (on root ports), and link bandwidth change notifications. The portbus driver will always claim the interrupt even if the individual port service drivers, such as pciehp, are compiled out. The second, bigger, problem is that the hotplug port service driver fundamentally does not work on PowerNV. The platform assumes that all PCI devices have a corresponding arch-specific handle derived from the DT node for the device (pci_dn) and without one the platform will not allow a PCI device to be enabled. This problem is largely due to historical baggage, but it can't be resolved without significant re-factoring of the platform PCI support. We can fix these problems in the interim by setting the "pcie_ports_disabled" flag during platform initialisation. The flag indicates the platform owns the PCIe ports which stops the portbus driver from being registered. This does have the side effect of disabling all port services drivers that is: AER, PME, BW notifications, hotplug, and DPC. However, this is not a huge disadvantage on PowerNV since these services are either unused or handled through other means. Fixes: 66725152fb9f ("PCI/hotplug: PowerPC PowerNV PCI hotplug driver") Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191118065553.30362-1-oohall@gmail.com Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/platforms/powernv/pci.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) --- a/arch/powerpc/platforms/powernv/pci.c +++ b/arch/powerpc/platforms/powernv/pci.c @@ -945,6 +945,23 @@ void __init pnv_pci_init(void) if (!firmware_has_feature(FW_FEATURE_OPAL)) return; +#ifdef CONFIG_PCIEPORTBUS + /* + * On PowerNV PCIe devices are (currently) managed in cooperation + * with firmware. This isn't *strictly* required, but there's enough + * assumptions baked into both firmware and the platform code that + * it's unwise to allow the portbus services to be used. + * + * We need to fix this eventually, but for now set this flag to disable + * the portbus driver. The AER service isn't required since that AER + * events are handled via EEH. The pciehp hotplug driver can't work + * without kernel changes (and portbus binding breaks pnv_php). The + * other services also require some thinking about how we're going + * to integrate them. + */ + pcie_ports_disabled = true; +#endif + /* Look for IODA IO-Hubs. */ for_each_compatible_node(np, NULL, "ibm,ioda-hub") { pnv_pci_init_ioda_hub(np);