From patchwork Sat Jul 2 09:08:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Huacai Chen X-Patchwork-Id: 12903943 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 22E47C43334 for ; Sat, 2 Jul 2022 09:10:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230262AbiGBJKS (ORCPT ); Sat, 2 Jul 2022 05:10:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229468AbiGBJKR (ORCPT ); Sat, 2 Jul 2022 05:10:17 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D84941ADB3 for ; Sat, 2 Jul 2022 02:10:16 -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 721E260AE9 for ; Sat, 2 Jul 2022 09:10:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B9D9C34114; Sat, 2 Jul 2022 09:10:13 +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 V15 4/7] PCI: loongson: Don't access non-existant devices Date: Sat, 2 Jul 2022 17:08:05 +0800 Message-Id: <20220702090808.1221300-5-chenhuacai@loongson.cn> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220702090808.1221300-1-chenhuacai@loongson.cn> References: <20220702090808.1221300-1-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 | 30 +++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c index a1222fc15454..de5be6d9bcbc 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; @@ -134,10 +135,17 @@ static void __iomem *cfg0_map(struct loongson_pci *priv, int bus, return priv->cfg0_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 char busnum = bus->number; + unsigned int device = PCI_SLOT(devfn); + unsigned int function = PCI_FUNC(devfn); struct loongson_pci *priv = pci_bus_to_loongson_pci(bus); if (pci_is_root_bus(bus)) @@ -147,9 +158,16 @@ static void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devf * 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 +215,12 @@ 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 +315,7 @@ 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);