From patchwork Thu Oct 21 15:07:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen Naidu X-Patchwork-Id: 12575503 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 1BF8DC433F5 for ; Thu, 21 Oct 2021 15:13:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF731611C7 for ; Thu, 21 Oct 2021 15:13:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232082AbhJUPQL (ORCPT ); Thu, 21 Oct 2021 11:16:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49702 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232069AbhJUPPj (ORCPT ); Thu, 21 Oct 2021 11:15:39 -0400 Received: from mail-pl1-x633.google.com (mail-pl1-x633.google.com [IPv6:2607:f8b0:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87153C06122C; Thu, 21 Oct 2021 08:13:13 -0700 (PDT) Received: by mail-pl1-x633.google.com with SMTP id f21so645644plb.3; Thu, 21 Oct 2021 08:13:13 -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=g4G4Yffk64HxtbjZzw9/E8PSnsLTvUujtQvSwE3J4gU=; b=cI4maM6sHC3cIMldIjQc1WksuleNIofwFqWYF4hgi1mSUPjEGy/WmXoWahcRKKe5+w j+zLwnck9MFzmr8MftgklxRZ5wNxIbu4G2AheKg9ZMv2lHgNNhGgL2J7UsV3l6gjZExb H4tZgM8wyBorCpeRi921+Tm3u0WVTydBr3Tj3cAhZ9aNPzvoqZ4hpLqS+KH5vxfSS8kl RuDF/0hlWT9G4JzVK0afVRra+EpY2rFrGAa9crTmNU2ssX8sWEbik9C86qDFbaKzhp+l Qiuu1E0eKf6ZEerz3y53kIBw8RH87UqQ0r1zBn0XyLQryf6q11P3qfumh997IU+rjQxH 8n1g== 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=g4G4Yffk64HxtbjZzw9/E8PSnsLTvUujtQvSwE3J4gU=; b=4BEaDgR7WXMTsTe4Hhmh2swoNTEFDsbhCIT0x5j0buBukkAk1fIyEAnqSafCC6pvZu id86LgmFzf+pNx5RvmJ/8Bojrzk/Rdxj2yazemefd6HBhHEQ8PpxEoaQITfuItW/osXE RMTc6vFaMlW0bGk9NBoda7nE6Jc70pxJdEvCguThwZEmMfz/ScZ4ua9N9750SpJAmLD+ me6RUVOSpO+a2IW4E+2y6+Yjpa1hWLvv5ezHhAgwOxemcRzbz3WPmqQl1QI8wXazyOsD 4Cix+I6cHPqbGQXC5o8YbPhi7WXEvHNmbisA/0VEUxvs1AAvmv9E7U4NyTnGIc5ohZys Epog== X-Gm-Message-State: AOAM532gsgqLtreMI6/Hiw4FCDM3XDDG94+aztRg+NQQVbYurGGAoKAI PzOptgrU4rYtj8/SRwMjWgM= X-Google-Smtp-Source: ABdhPJwuN72upSJVb5RV31HWJ0Rk/DS/k3MWELCcfxWrH5dP6+GQCb3WOGhj7YB/ramfc8/eTUFdtQ== X-Received: by 2002:a17:90b:1a87:: with SMTP id ng7mr7478114pjb.69.1634829192977; Thu, 21 Oct 2021 08:13:12 -0700 (PDT) Received: from localhost.localdomain ([2406:7400:63:29a4:d874:a949:6890:f95f]) by smtp.gmail.com with ESMTPSA id c9sm5508027pgq.58.2021.10.21.08.13.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Oct 2021 08:13:12 -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, Shawn Lin , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , Heiko Stuebner , linux-rockchip@lists.infradead.org (open list:PCIE DRIVER FOR ROCKCHIP), linux-arm-kernel@lists.infradead.org (moderated list:ARM/Rockchip SoC support) Subject: [PATCH v3 15/25] PCI: rockchip: Remove redundant error fabrication when device read fails Date: Thu, 21 Oct 2021 20:37:40 +0530 Message-Id: <59113f443210c0c4d9d7696b22274c21ec2b7276.1634825082.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. Signed-off-by: Naveen Naidu --- drivers/pci/controller/pcie-rockchip-host.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c index c52316d0bfd2..45a28880f322 100644 --- a/drivers/pci/controller/pcie-rockchip-host.c +++ b/drivers/pci/controller/pcie-rockchip-host.c @@ -221,10 +221,8 @@ static int rockchip_pcie_rd_conf(struct pci_bus *bus, u32 devfn, int where, { struct rockchip_pcie *rockchip = bus->sysdata; - if (!rockchip_pcie_valid_device(rockchip, bus, PCI_SLOT(devfn))) { - *val = 0xffffffff; + if (!rockchip_pcie_valid_device(rockchip, bus, PCI_SLOT(devfn))) return PCIBIOS_DEVICE_NOT_FOUND; - } if (pci_is_root_bus(bus)) return rockchip_pcie_rd_own_conf(rockchip, where, size, val);