From nobody Sun Sep 22 15:22:41 2024 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 DDD2EC433F5 for ; Thu, 18 Nov 2021 14:07:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C2BBB61AE2 for ; Thu, 18 Nov 2021 14:07:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232471AbhKROKo (ORCPT ); Thu, 18 Nov 2021 09:10:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38468 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232460AbhKROKm (ORCPT ); Thu, 18 Nov 2021 09:10:42 -0500 Received: from mail-pj1-x1033.google.com (mail-pj1-x1033.google.com [IPv6:2607:f8b0:4864:20::1033]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E371C061570; Thu, 18 Nov 2021 06:07:42 -0800 (PST) Received: by mail-pj1-x1033.google.com with SMTP id gb13-20020a17090b060d00b001a674e2c4a8so5792817pjb.4; Thu, 18 Nov 2021 06:07:42 -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=j6PFmrQZfsZKbN43caoyPHUp+nOh1/rI/bPUZ2uC0hc=; b=BvRkTG9QWh/nDql0vdChRnHccpwZ0VM4CIM6EBHq/1BgkYqp8nyvYg5knfbTMtAm9S ONlfHuNPSw+chm+zhOREpoCqOzSkBHPKq75nMzMfYfiZlXJxO1UzO+C4gtA3QmzLKDht 5Bh9Bb28TGsINdTlHnoi5ncLJOJaSg/5E0PcUP9CNVvwPbL1vmYQSvju02y+it/aKDyo bHC7GrlUfpx1NQeiTbAYZCf2+wSQkkFEQBQnTN0Oj1LnMZ4GV0qjtQiwT0flkCu+B/VH bQ/E1ZigUq2WIZaIk1/PHMG9CyxkEykKLu6Udtb8QqjOAh1HqyDy+b9+qLN6PKFCLy2B JMig== 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=j6PFmrQZfsZKbN43caoyPHUp+nOh1/rI/bPUZ2uC0hc=; b=7vZzS6Ej42orbFfZrrFKLd3ifYQsJ3HHzakG4x17HHQ7bhVyGk4k4MrNsJdbpTxri2 Yimtn2Xc9NWHraGlYmJHf4KXbt+DAATfACUzxGn/aBAnvvaF9YsVoyZTVrTGrJ7W9D89 9+9IngD4LskIfRNRzbvbnwlmMS0yAfIy1oO9fCDryMKDeEW5yeH5w0aMzRBbBbfOPdWJ iRfEwrfD2hjpXbE8LcV965FeT1zYYp8nFlKGdHFMVjKdNUXR5TQYA7LVckH2WLU7CsND bT8cYGqhi/v6MCKR6MxqMEk6+L9ByZdWRG+cwyX4KNqlCbb8Xa6u+D57p3fDMnm9NG4v 40GA== X-Gm-Message-State: AOAM533xUDHaRTM4o79zkTLEkMw6+4rhmCmJqRHxdv9WOfqSJZgdVz7F aCzBmgcIClFkZC+j6KdoiS0= X-Google-Smtp-Source: ABdhPJyvJjeiaFKSgytjId5brKyWz+xbwXrqFdhy7A6dGUOrftB/u/RY89uvHrTE/ZR0106/YqLWVA== X-Received: by 2002:a17:90b:3b81:: with SMTP id pc1mr10785668pjb.67.1637244462074; Thu, 18 Nov 2021 06:07:42 -0800 (PST) Received: from localhost.localdomain ([2406:7400:63:2c47:5ffe:fc34:61f0:f1ea]) by smtp.gmail.com with ESMTPSA id x14sm2822878pjl.27.2021.11.18.06.07.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Nov 2021 06:07:41 -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, Thomas Petazzoni , Lorenzo Pieralisi , Rob Herring , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , linux-arm-kernel@lists.infradead.org Subject: [PATCH v4 12/25] PCI: mvebu: Remove redundant error fabrication when device read fails Date: Thu, 18 Nov 2021 19:33:22 +0530 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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/pci-mvebu.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pc= i-mvebu.c index ed13e81cd691..70a96af8cd2f 100644 --- a/drivers/pci/controller/pci-mvebu.c +++ b/drivers/pci/controller/pci-mvebu.c @@ -653,20 +653,16 @@ static int mvebu_pcie_rd_conf(struct pci_bus *bus, u3= 2 devfn, int where, int ret; =20 port =3D mvebu_pcie_find_port(pcie, bus, devfn); - if (!port) { - *val =3D 0xffffffff; + if (!port) return PCIBIOS_DEVICE_NOT_FOUND; - } =20 /* Access the emulated PCI-to-PCI bridge */ if (bus->number =3D=3D 0) return pci_bridge_emul_conf_read(&port->bridge, where, size, val); =20 - if (!mvebu_pcie_link_up(port)) { - *val =3D 0xffffffff; + if (!mvebu_pcie_link_up(port)) return PCIBIOS_DEVICE_NOT_FOUND; - } =20 /* Access the real PCIe interface */ ret =3D mvebu_pcie_hw_rd_conf(port, bus, devfn, --=20 2.25.1