From patchwork Thu Nov 18 14:03:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen Naidu X-Patchwork-Id: 12627115 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 E4A4BC433F5 for ; Thu, 18 Nov 2021 14:07:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C8B2B61107 for ; Thu, 18 Nov 2021 14:07:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232487AbhKROKz (ORCPT ); Thu, 18 Nov 2021 09:10:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232503AbhKROKy (ORCPT ); Thu, 18 Nov 2021 09:10:54 -0500 Received: from mail-pf1-x42c.google.com (mail-pf1-x42c.google.com [IPv6:2607:f8b0:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89E93C061570; Thu, 18 Nov 2021 06:07:54 -0800 (PST) Received: by mail-pf1-x42c.google.com with SMTP id x5so6175666pfr.0; Thu, 18 Nov 2021 06:07:54 -0800 (PST) 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=MC+uMtAqzrUGxiPuMGV2uquDaVscrAuApobHOB73Khc=; b=iujRsX4QPoiun7MHP0bUBZW28PjBf6o6gfGjY/YCm/Lpia8P/wzPGdCWhiyGfZG09g Gjrmitr/DvKW1Se/u30W1xBctEtQ460BlEKz4w4a4RRLsG/Z9uYu8quQ3S8YNaXabwUL c0ODX2zYAPzZEc+6s3kYCQfPner0LQoYLnPLwcCCQxCnx5DSiPpfmdj91JA28o2Bh+zR Xxth8mCjdAdYY8DkskQ2AL8PFVJqPwsIgFNlvyqn9V5Q7seZuDDq1aaOMfpUVkRLcLVb p2wov/u8f1vPaBr2+y9SQZFEwiXZ5iREzuqbl0+ygDk3ftzRQ2vbE6NVCZ+zPwJOU+sx PG0A== 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=MC+uMtAqzrUGxiPuMGV2uquDaVscrAuApobHOB73Khc=; b=4AmvMsilUFcc9yAL0G1NHGdVHQX1A7b376rkqlxdCW3fwAule/EkVKnarNDNZD3Xu5 tw4mRzYvBHUKfiaiNzF2p9tjsSBevq4V9FOCFvpE8yPhMviUvEw/XB+Bx0Y2Q//kGoW1 8ALbAfFz87Bs6bf3PDZC12jP2z1a/mU+45oXSzBuw7p8hzzJ/z/QfOtEsh9tEo9sUmxY fDxW/SoMlmOoBAtuNDyFG4cBYMHi0bdrWWV8DNjOKn9aj8S/AYNF7V3bHUWrNY9O8xpA SlNGlem4d4+n1R9jhu92AB0e+ejDvdcmFwdNBWzPIVsEPLlvFcnDoXGZsze7PimU23gG 1R/w== X-Gm-Message-State: AOAM530nda8+C5DufGi/C/JmEO2M1TdPnqCfjpgdGjG/TehvRG0JrR3x G0qPPrz7epsTWAQALOGPXJw= X-Google-Smtp-Source: ABdhPJyuYGF3D5BwP9dBQadEZLcKBgGb+caRhXPH1nLvYia+cdRfnIzBQGuarTkOzB+UKMsDzzIvlg== X-Received: by 2002:a63:725e:: with SMTP id c30mr11339989pgn.240.1637244474011; Thu, 18 Nov 2021 06:07:54 -0800 (PST) Received: from localhost.localdomain ([2406:7400:63:2c47:5ffe:fc34:61f0:f1ea]) by smtp.gmail.com with ESMTPSA id x14sm2822878pjl.27.2021.11.18.06.07.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Nov 2021 06:07:53 -0800 (PST) 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, Geert Uytterhoeven , Marek Vasut , Yoshihiro Shimoda , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , linux-renesas-soc@vger.kernel.org (open list:PCI DRIVER FOR RENESAS R-CAR) Subject: [PATCH v4 14/25] PCI: rcar: Remove redundant error fabrication when device read fails Date: Thu, 18 Nov 2021 19:33:24 +0530 Message-Id: <83540eb3ae76a0d28bbe03d69d685a6d549b456b.1637243717.git.naveennaidu479@gmail.com> 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. Reviewed-by: Geert Uytterhoeven Signed-off-by: Naveen Naidu --- drivers/pci/controller/pcie-rcar-host.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c index e12c2d8be05a..6bd5619fbbf4 100644 --- a/drivers/pci/controller/pcie-rcar-host.c +++ b/drivers/pci/controller/pcie-rcar-host.c @@ -159,10 +159,8 @@ static int rcar_pcie_read_conf(struct pci_bus *bus, unsigned int devfn, ret = rcar_pcie_config_access(host, RCAR_PCI_ACCESS_READ, bus, devfn, where, val); - if (ret != PCIBIOS_SUCCESSFUL) { - *val = 0xffffffff; + if (ret != PCIBIOS_SUCCESSFUL) return ret; - } if (size == 1) *val = (*val >> (BITS_PER_BYTE * (where & 3))) & 0xff;