From patchwork Thu Jul 14 12:42:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Huacai Chen X-Patchwork-Id: 12917856 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 A86C0C43334 for ; Thu, 14 Jul 2022 12:47:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239586AbiGNMrW (ORCPT ); Thu, 14 Jul 2022 08:47:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239173AbiGNMrC (ORCPT ); Thu, 14 Jul 2022 08:47:02 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF7596170C for ; Thu, 14 Jul 2022 05:45:17 -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 dfw.source.kernel.org (Postfix) with ESMTPS id B6C2961F91 for ; Thu, 14 Jul 2022 12:45:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB01AC34115; Thu, 14 Jul 2022 12:45:12 +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 V16 4/7] PCI: loongson: Don't access non-existant devices Date: Thu, 14 Jul 2022 20:42:13 +0800 Message-Id: <20220714124216.1489304-5-chenhuacai@loongson.cn> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220714124216.1489304-1-chenhuacai@loongson.cn> References: <20220714124216.1489304-1-chenhuacai@loongson.cn> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On LS2K/LS7A, some non-existant devices don't return 0xffffffff when scanning (they are hidden devices for debug in fact, access the config space may cause machine hang). This is a hardware flaw but we can only avoid it by software now. Signed-off-by: Huacai Chen --- drivers/pci/controller/pci-loongson.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c index 2db180a9e628..594653154deb 100644 --- a/drivers/pci/controller/pci-loongson.c +++ b/drivers/pci/controller/pci-loongson.c @@ -26,6 +26,7 @@ #define FLAG_CFG0 BIT(0) #define FLAG_CFG1 BIT(1) #define FLAG_DEV_FIX BIT(2) +#define FLAG_DEV_HIDDEN BIT(3) struct loongson_pci_data { u32 flags; @@ -138,18 +139,32 @@ static void __iomem *cfg1_map(struct loongson_pci *priv, return priv->cfg1_base + addroff; } +static bool pdev_may_exist(struct pci_bus *bus, unsigned int device, unsigned int function) +{ + return !(pci_is_root_bus(bus) && (device >= 9 && device <= 20) && (function > 0)); +} + static void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devfn, int where) { + unsigned int device = PCI_SLOT(devfn); + unsigned int function = PCI_FUNC(devfn); struct loongson_pci *priv = pci_bus_to_loongson_pci(bus); /* * Do not read more than one device on the bus other than * the host bus. */ - if (priv->data->flags & FLAG_DEV_FIX && - !pci_is_root_bus(bus) && PCI_SLOT(devfn) > 0) - return NULL; + if ((priv->data->flags & FLAG_DEV_FIX) && bus->self) { + if (!pci_is_root_bus(bus) && (device > 0)) + return NULL; + } + + /* Don't access non-existant devices */ + if (priv->data->flags & FLAG_DEV_HIDDEN) { + if (!pdev_may_exist(bus, device, function)) + return NULL; + } /* CFG0 can only access standard space */ if (where < PCI_CFG_SPACE_SIZE && priv->cfg0_base) @@ -197,12 +212,12 @@ static struct pci_ops loongson_pci_ops32 = { }; static const struct loongson_pci_data ls2k_pci_data = { - .flags = FLAG_CFG1 | FLAG_DEV_FIX, + .flags = FLAG_CFG1 | FLAG_DEV_FIX | FLAG_DEV_HIDDEN, .ops = &loongson_pci_ops, }; static const struct loongson_pci_data ls7a_pci_data = { - .flags = FLAG_CFG1 | FLAG_DEV_FIX, + .flags = FLAG_CFG1 | FLAG_DEV_FIX | FLAG_DEV_HIDDEN, .ops = &loongson_pci_ops, }; @@ -297,7 +312,7 @@ static int loongson_pci_ecam_init(struct pci_config_window *cfg) return -ENOMEM; cfg->priv = priv; - data->flags = FLAG_CFG1; + data->flags = FLAG_CFG1 | FLAG_DEV_HIDDEN; priv->data = data; priv->cfg1_base = cfg->win - (cfg->busr.start << 16);