From patchwork Mon Oct 11 17:37:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen Naidu X-Patchwork-Id: 12550705 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 D00EFC4332F for ; Mon, 11 Oct 2021 17:38:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B365B60EDF for ; Mon, 11 Oct 2021 17:38:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233262AbhJKRkJ (ORCPT ); Mon, 11 Oct 2021 13:40:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232277AbhJKRkJ (ORCPT ); Mon, 11 Oct 2021 13:40:09 -0400 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F76BC06161C; Mon, 11 Oct 2021 10:38:09 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id y1so11767872plk.10; Mon, 11 Oct 2021 10:38:09 -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=WTDymu/kK4gMRJAHOJpsOJeHyCsZ/lww9DjrtPbDpJ4=; b=HwHRRV+S/RE+GIDbxexsfa91uds8RaTJQMPwbLhyAkzd491qats0xSsaC4mhiRl6Jq gXXjtWMCRFCl24UDsqtfCnqLD1Cbtd/93S7HO5AgB4ueGG4bEHV+hcSl1HJMqS26/8sA AKDOYmV4WnzsAqwxPmP3185eWqTzwnWRl2QPIf3ODwukpfqNg79k8CXYXbmjBmwmlM7H JLjBNNDOGJ+Mxf3ToELn+xPiqYpbj9hM9X5kn0apcvp1wMCYCAV20W1pQqigoIPr8oqY TGxAUPwne4Rec2JXIdYu17BaZHyNtS6uIqjuojEWOKeCG+TbAaPT/AAhWcUg9ysN4hhq wH4g== 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=WTDymu/kK4gMRJAHOJpsOJeHyCsZ/lww9DjrtPbDpJ4=; b=pEySNMGyfKN0LhsuGrEnaujwUsG5yy6keiiDjkenRyt3junaA3t6EcHB56bVO7oMwO 0fb2kE434Zw9nkXAY7/mIPsVxmJoqo5S1AGtZpZAUBiLv2vi/Vb+HAzCTh20wXnOGpqC r4zif068qL9Yq6zL8DsYMHBvJciETqaWZfNHr3uBAfi4dpfVvk/TbPShtKh3+cqrArtC o1a/K9al8UtgA7R53YZYeQKbn5U6d4JPG4rz059vRD+UM2WjLZmWtT+/UIH80WCPFEm0 1wygVF7NXAbu9qlbcaklqLDeZnEqgXdQtEmrA8XDJweoqf6vUgGylV6HlXmSqCe8+uTZ 930Q== X-Gm-Message-State: AOAM531MbS8/QzG1i8jH5G3lMUkVTy/ddLFaUTtkmAAAJ2r9HbjuTUZ9 hdYAxTIT6a72KSJFGt0nqfo= X-Google-Smtp-Source: ABdhPJxEBdoXamrVCKeesJUkEsfNWnP0PDrt34jLeyC7FqCvn2xqaY1LwruNHL9Qwq4e9o9alifRPA== X-Received: by 2002:a17:90a:67c1:: with SMTP id g1mr335114pjm.177.1633973888608; Mon, 11 Oct 2021 10:38:08 -0700 (PDT) Received: from localhost.localdomain ([2406:7400:63:9f95:848b:7cc8:d852:ad42]) by smtp.gmail.com with ESMTPSA id c12sm8456919pfc.161.2021.10.11.10.38.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Oct 2021 10:38:08 -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, linux-arm-kernel@lists.infradead.org, bcm-kernel-feedback-list@broadcom.com, linux-mediatek@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-rockchip@lists.infradead.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH 01/22] PCI: Add PCI_ERROR_RESPONSE and it's related defintions Date: Mon, 11 Oct 2021 23:07:53 +0530 Message-Id: <5b4ba38fa56c7625d391383a3aed47dea6726946.1633972263.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. Add a PCI_ERROR_RESPONSE definition for that and use it where appropriate to make these checks consistent and easier to find. Also add helper definitions SET_PCI_ERROR_RESPONSE and RESPONSE_IS_PCI_ERROR to make the code more readable. Signed-off-by: Naveen Naidu --- include/linux/pci.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/include/linux/pci.h b/include/linux/pci.h index cd8aa6fce204..928c589bb5c4 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -154,6 +154,15 @@ enum pci_interrupt_pin { /* The number of legacy PCI INTx interrupts */ #define PCI_NUM_INTX 4 +/* + * Reading from a device that doesn't respond typically returns ~0. A + * successful read from a device may also return ~0, so you need additional + * information to reliably identify errors. + */ +#define PCI_ERROR_RESPONSE (~0ULL) +#define SET_PCI_ERROR_RESPONSE(val) (*val = ((typeof(*val)) PCI_ERROR_RESPONSE)) +#define RESPONSE_IS_PCI_ERROR(val) (*val == ((typeof(*val)) PCI_ERROR_RESPONSE)) + /* * pci_power_t values must match the bits in the Capabilities PME_Support * and Control/Status PowerState fields in the Power Management capability.