From patchwork Thu Oct 21 15:07:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen Naidu X-Patchwork-Id: 12575425 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 6A36BC433F5 for ; Thu, 21 Oct 2021 15:11:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 563EE610A2 for ; Thu, 21 Oct 2021 15:11:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231787AbhJUPNY (ORCPT ); Thu, 21 Oct 2021 11:13:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49166 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231784AbhJUPNX (ORCPT ); Thu, 21 Oct 2021 11:13:23 -0400 Received: from mail-pg1-x52b.google.com (mail-pg1-x52b.google.com [IPv6:2607:f8b0:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6408C061348; Thu, 21 Oct 2021 08:11:07 -0700 (PDT) Received: by mail-pg1-x52b.google.com with SMTP id r2so574072pgl.10; Thu, 21 Oct 2021 08:11:07 -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=E2kMW7De0WUTFR8R6pbmw+v+DfoEFjJfFZEPmx6TpIo=; b=bzWdSeZQujO32b5BMXmzC0hhRwPksEaiJE/YCATPkO92U0l+nmR4WGg3cVxc0hTdyz FEiwDhNx3vFODZnaOwNJgeNx0e8s9VBE4HACA2WQtqadySltUFMRd4kiTbex9lmpKjce 4OU4FX1VyEsIA2rp6LEjNuvr7zj4dR/48s7cnxdC1nFzwHVkbFVZFqn+L/n6KvocLObi /Xro4uDDTsrKtYwU2fe5EgmulOTv0YFTQt/SrAZ4iN2CbapeYV6/AF9/iayp6Gix1gdW QIyfLJ+azZ1EVH0YzaszjJDw32Rygn46IcE9+H14XdELtLHoCGDulU6jFktpuLeWb6z4 Z1hg== 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=E2kMW7De0WUTFR8R6pbmw+v+DfoEFjJfFZEPmx6TpIo=; b=bnktslb/yZKDnPpuodKVtxCo2+hsAt2L3V4odwZ8rb4/qneJ86NhKZjSH61JqKVfMd EnbS7IwYj8K4e9Rcmte1vH6zE0Kvahd7Yj8eUzCjIJ/+cxZybpj5vuVPwzKmtSwKYa4r Vo75xV1YUpKGcK5UE011k3qdVxIzWXus2sF6ba7q/2mfTQscuI5l6LS/BDUjx4KpOMrh 9fJaLLRhqnDhtbs/72hKopFbycfTcDT12wJpXPX63iHdHx5v7sdf4uBIVp6kOfgFjBMj 6oDrxFqFRVHQFTl6qPT2nZs4bnKMILUrAgvIN/Hz0d6yQhCPWYOOuB6fo9I56xX4E9lP PVLw== X-Gm-Message-State: AOAM531FP1b3rMOFVxCCLHuCnSIEqe1Vec4z7b/qkEHhlPdWDc2qAWk5 McUcrtH+IU7nj/+JXkU2N5Q= X-Google-Smtp-Source: ABdhPJxg0pcHZ6TPn2MFYXLLISmkE9s8HA75KNL2gwUrIwqR1ZdHdF+RKfas5XSIW73ZAHG7QCE0Lw== X-Received: by 2002:a05:6a00:b45:b0:44d:c4c4:409b with SMTP id p5-20020a056a000b4500b0044dc4c4409bmr6124670pfo.3.1634829067053; Thu, 21 Oct 2021 08:11:07 -0700 (PDT) Received: from localhost.localdomain ([2406:7400:63:29a4:d874:a949:6890:f95f]) by smtp.gmail.com with ESMTPSA id c9sm5508027pgq.58.2021.10.21.08.11.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Oct 2021 08:11:06 -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, Ryder Lee , Jianjun Wang , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , Matthias Brugger , linux-mediatek@lists.infradead.org (open list:PCIE DRIVER FOR MEDIATEK), linux-arm-kernel@lists.infradead.org (moderated list:ARM/Mediatek SoC support) Subject: [PATCH v3 07/25] PCI: mediatek: Remove redundant error fabrication when device read fails Date: Thu, 21 Oct 2021 20:37:32 +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-mediatek.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c index 2f3f974977a3..a19f8ec5d392 100644 --- a/drivers/pci/controller/pcie-mediatek.c +++ b/drivers/pci/controller/pcie-mediatek.c @@ -365,19 +365,12 @@ static int mtk_pcie_config_read(struct pci_bus *bus, unsigned int devfn, { struct mtk_pcie_port *port; u32 bn = bus->number; - int ret; port = mtk_pcie_find_port(bus, devfn); - if (!port) { - *val = ~0; + if (!port) return PCIBIOS_DEVICE_NOT_FOUND; - } - - ret = mtk_pcie_hw_rd_cfg(port, bn, devfn, where, size, val); - if (ret) - *val = ~0; - return ret; + return mtk_pcie_hw_rd_cfg(port, bn, devfn, where, size, val); } static int mtk_pcie_config_write(struct pci_bus *bus, unsigned int devfn,