From patchwork Sat Apr 30 08:48:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Huacai Chen X-Patchwork-Id: 12833097 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 6F828C433EF for ; Sat, 30 Apr 2022 08:49:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231947AbiD3IxJ (ORCPT ); Sat, 30 Apr 2022 04:53:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229530AbiD3IxJ (ORCPT ); Sat, 30 Apr 2022 04:53:09 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC521B16 for ; Sat, 30 Apr 2022 01:49:48 -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 48D9860C8B for ; Sat, 30 Apr 2022 08:49:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12063C385A7; Sat, 30 Apr 2022 08:49:44 +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, Xuefeng Li , Huacai Chen , Jiaxun Yang , Huacai Chen Subject: [PATCH V13 3/6] PCI: loongson: Don't access unexisting devices Date: Sat, 30 Apr 2022 16:48:43 +0800 Message-Id: <20220430084846.3127041-4-chenhuacai@loongson.cn> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220430084846.3127041-1-chenhuacai@loongson.cn> References: <20220430084846.3127041-1-chenhuacai@loongson.cn> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On LS2K/LS7A, some unexisting devices don't return 0xffffffff when scanning. 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 | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c index adbfa4a2330f..48316daa1f23 100644 --- a/drivers/pci/controller/pci-loongson.c +++ b/drivers/pci/controller/pci-loongson.c @@ -138,6 +138,8 @@ static void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devf 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)) @@ -147,8 +149,13 @@ 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. For our hardware the root bus is always bus 0. */ - if (priv->data->flags & FLAG_DEV_FIX && - !pci_is_root_bus(bus) && PCI_SLOT(devfn) > 0) + if ((priv->data->flags & FLAG_DEV_FIX) && bus->self) { + if (!pci_is_root_bus(bus) && (device > 0)) + return NULL; + } + + /* Don't access unexisting devices */ + if (pci_is_root_bus(bus) && (device >= 9 && device <= 20 && function > 0)) return NULL; /* CFG0 can only access standard space */