From patchwork Thu Oct 21 15:07:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen Naidu X-Patchwork-Id: 12575423 X-Patchwork-Delegate: bhelgaas@google.com 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F1F8C433EF for ; Thu, 21 Oct 2021 15:11:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 424DD610A2 for ; Thu, 21 Oct 2021 15:11:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231605AbhJUPNR (ORCPT ); Thu, 21 Oct 2021 11:13:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49134 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230072AbhJUPNQ (ORCPT ); Thu, 21 Oct 2021 11:13:16 -0400 Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D2BA8C0613B9; Thu, 21 Oct 2021 08:11:00 -0700 (PDT) Received: by mail-pl1-x629.google.com with SMTP id e10so618450plh.8; Thu, 21 Oct 2021 08:11:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=r3o5gBqF0m60j/685v1gCV+85CWmYdPsbI4M53MCV74=; b=i2E12Gf3MradRaA6L+Vcc5Lo6XtZ/fVf/ZWnm8oDtjsE4xTJqRT+l19jozuA+esT+h PJFe/cy5U/ogFT/dPLmB/2eJP5WH67mC0Sc6YJpFdLeE4wCg+AtGoUkNW5E763Ake4L1 0mcJ4mk+yV5TKnLMWZUW0IFVz7ar2ciGv/Idb1uiTPEGS3aWtW0BH2zd2XvhO4uuGgqo c7t7w0ryMTIwqzsTWcp4XZqpzvVnoYlrP76HIhR4rwn5vX9hP2pa4b+gPjiRbyKUUKcL 9NH1RMGqUzPBQky4qUSGPv/4fbzQrRqvp4yp0IaUz2uFsJ/p2EIPz94JzBz5Js1HQjDE u5jw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=r3o5gBqF0m60j/685v1gCV+85CWmYdPsbI4M53MCV74=; b=3XyYOStHxqYX3ROqZBWIK7d993kIMWVp5pXJ6B1UG9nNGwnjoGHDWHH5yDqbOjIFHE LzuAny2DMMSw3SZCzFpEx6Xp4lOvYWtcPOWdkP+FVueIMrelSt/dYU3NKiw+6pHO4P+K iQcAsmh8u+alWmpP4txR3sGhltZwr5DlwzrmqbXgCo1+Pdys9YcPXvkwCJRqtv+AKKpa fmudTPR7tvBrxIl4ys8/MU0KrEa7EHMZTpFazmkKkjjWDA9rbXO28emo8RInsRepY2yF idHZz1k/ROvMWc8EMWYzw5yti96tUstIo7Ssly/U4f6Teq78k2yM8BTLDkEeJgFdZ4ZU 7j1w== X-Gm-Message-State: AOAM533Yp0kPHvZ9AVCHwCzhhlgVKC7OqkNfErUGiUlRvLxh7fS6LR2r Un8K0hy5Z2pzPUaXIYG74Bk= X-Google-Smtp-Source: ABdhPJxFk7e1vtp4qHS3c1Zxn06yJuOA57fAM3iyNvU3T73javJynq35EJA8Ilbs3c18IIVc7E5eZQ== X-Received: by 2002:a17:90b:3809:: with SMTP id mq9mr7304004pjb.7.1634829060352; Thu, 21 Oct 2021 08:11:00 -0700 (PDT) Received: from localhost.localdomain ([2406:7400:63:29a4:d874:a949:6890:f95f]) by smtp.gmail.com with ESMTPSA id c9sm5508027pgq.58.2021.10.21.08.10.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Oct 2021 08:10:59 -0700 (PDT) From: Naveen Naidu To: bhelgaas@google.com Cc: Naveen Naidu , linux-kernel-mentees@lists.linuxfoundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , Ray Jui , Scott Branden , bcm-kernel-feedback-list@broadcom.com (maintainer:BROADCOM IPROC ARM ARCHITECTURE), linux-arm-kernel@lists.infradead.org (moderated list:BROADCOM IPROC ARM ARCHITECTURE) Subject: [PATCH v3 06/25] PCI: iproc: Remove redundant error fabrication when device read fails Date: Thu, 21 Oct 2021 20:37:31 +0530 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org An MMIO read from a PCI device that doesn't exist or doesn't respond causes a PCI error. There's no real data to return to satisfy the CPU read, so most hardware fabricates ~0 data. The host controller drivers sets the error response values (~0) and returns an error when faulty hardware read occurs. But the error response value (~0) is already being set in PCI_OP_READ and PCI_USER_READ_CONFIG whenever a read by host controller driver fails. Thus, it's no longer necessary for the host controller drivers to fabricate any error response. This helps unify PCI error response checking and make error check consistent and easier to find. Signed-off-by: Naveen Naidu --- drivers/pci/controller/pcie-iproc.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c index 30ac5fbefbbf..e3d86416a4fb 100644 --- a/drivers/pci/controller/pcie-iproc.c +++ b/drivers/pci/controller/pcie-iproc.c @@ -659,10 +659,8 @@ static int iproc_pci_raw_config_read32(struct iproc_pcie *pcie, void __iomem *addr; addr = iproc_pcie_map_cfg_bus(pcie, 0, devfn, where & ~0x3); - if (!addr) { - *val = ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } *val = readl(addr);