From nobody Sun Sep 22 15:27:29 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 DD159C433FE for ; Thu, 18 Nov 2021 14:06:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC87B60EFD for ; Thu, 18 Nov 2021 14:06:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232442AbhKROJI (ORCPT ); Thu, 18 Nov 2021 09:09:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232408AbhKROJH (ORCPT ); Thu, 18 Nov 2021 09:09:07 -0500 Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9290C061570; Thu, 18 Nov 2021 06:06:06 -0800 (PST) Received: by mail-pg1-x52e.google.com with SMTP id h63so5382126pgc.12; Thu, 18 Nov 2021 06:06:06 -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=FA4eEA0vKwb58YOkbLP9K2NVmJYtwGLqPjb+iaCxg5k=; b=pvFZ0MRzAJrj8pt979HKbEHcM6RZZRo84yo77627EYv7H5wrgSzp+Tof5GsOgr6wmL DPAA5oSOmTX+Fz9oXY1GFjV6XxP3Csvm+jcu9V+6t0GXEPIpTIPxC1geB6HIdWwuNY4+ sk5l4jsU1SifopQYlOtZLV/P7hdsHgV/2wh8F7PAJP6ZDNRNJ7N5pBGj3aK75YfFhZRZ GCJiIHMbk96TSg8nM0qOcdoXp3pcX5B9K16CH3HC+YiYhAI2ZWtytvT0NZWV5uq2bCW3 zKdewD7ldn6cCDPa9jaZ4J++AeBybJbKcswV3mfPUtq+bCJ6Kj3bYaaYTlPv+vW4Ecze rKGw== 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=FA4eEA0vKwb58YOkbLP9K2NVmJYtwGLqPjb+iaCxg5k=; b=rbyJ/HfDcagt1dcCXRWx/an0sUjFh15SC+yggi4lSUnU9W+h8rFlBWATOvgGIJudWu McqfeuYxNX2mJVeo3LCaU7cvjZPsjNS+El16Y+/2t5qEGXpi79m/D5giPz0avm2rJdxH mTfzPjKh+RVlbEIF9f/E3mmD49tLOh/EyEhaodBKCv+tcFcF8e237VwKtyEQDE/9rTej mffyO6WVcJ8aP51Hv3bfcXnxQNFLdH0c4m9DsvBj8OXiaokPA9EDjJ+Jc97YZViHLHxn Ycu4830eZuTMioHfTS+eoFQO3dVfO6FfOyZZtXaKIHARa7PA4e5NRAixSVUMrgfWDoVc GAGw== X-Gm-Message-State: AOAM532tfMUnMZ2n+fRF1vS/09DRxhOUVluypKTKDPfcJWn/NPkgs80z O0BpxMZzqqxyMmAS39lvKrk= X-Google-Smtp-Source: ABdhPJyYmcR/6DtK9DVRdL5nij9z3SmJ2ySPLjdsrWeskedGCKj8rft+HErV7xfOCFlSXzH7EUe/EQ== X-Received: by 2002:a65:5589:: with SMTP id j9mr11358991pgs.291.1637244366422; Thu, 18 Nov 2021 06:06:06 -0800 (PST) Received: from localhost.localdomain ([2406:7400:63:2c47:5ffe:fc34:61f0:f1ea]) by smtp.gmail.com with ESMTPSA id x14sm2822878pjl.27.2021.11.18.06.06.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Nov 2021 06:06:06 -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, Shawn Guo , Lorenzo Pieralisi , Rob Herring , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= Subject: [PATCH v4 09/25] PCI: histb: Remove redundant error fabrication when device read fails Date: Thu, 18 Nov 2021 19:33:19 +0530 Message-Id: <7da7ea760abc5f85cad6e9b0d3e59eebd93f50d3.1637243717.git.naveennaidu479@gmail.com> 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/dwc/pcie-histb.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-histb.c b/drivers/pci/controll= er/dwc/pcie-histb.c index 86f9d16c50d7..410555dccb6d 100644 --- a/drivers/pci/controller/dwc/pcie-histb.c +++ b/drivers/pci/controller/dwc/pcie-histb.c @@ -127,10 +127,8 @@ static int histb_pcie_rd_own_conf(struct pci_bus *bus,= unsigned int devfn, { struct dw_pcie *pci =3D to_dw_pcie_from_pp(bus->sysdata); =20 - if (PCI_SLOT(devfn)) { - *val =3D ~0; + if (PCI_SLOT(devfn)) return PCIBIOS_DEVICE_NOT_FOUND; - } =20 *val =3D dw_pcie_read_dbi(pci, where, size); return PCIBIOS_SUCCESSFUL; --=20 2.25.1