From patchwork Thu Oct 21 15:07:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Naveen Naidu X-Patchwork-Id: 12575433 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 EC545C433EF for ; Thu, 21 Oct 2021 15:11:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D505860F9F for ; Thu, 21 Oct 2021 15:11:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231828AbhJUPOM (ORCPT ); Thu, 21 Oct 2021 11:14:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230000AbhJUPOM (ORCPT ); Thu, 21 Oct 2021 11:14:12 -0400 Received: from mail-pf1-x436.google.com (mail-pf1-x436.google.com [IPv6:2607:f8b0:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9CEDC0613B9; Thu, 21 Oct 2021 08:11:55 -0700 (PDT) Received: by mail-pf1-x436.google.com with SMTP id m14so906582pfc.9; Thu, 21 Oct 2021 08:11:55 -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=3zEq2AfHmzmiP6iMn6OVsjvfYEnKpi8akIlRzP+t4I8=; b=pX96mXwiXPeCcU/ZLXG+82KZ6X1WwZf7RX3Kw1oTJXJycww++ljoclt7YyZKGpMDD+ 5l7uHnUBBtAH9GLNcQIhXR7I/ykoIVERhA0RlU5kuEWYgPTonPpKkAEhltbqXzkLMfnA rYYVpWcaqQQQtDXee/oBhUP9Gu6Ht6SlR6A9LzEh4O/+QIMrqFdUz0hY1NGJguRPysU6 4DLYEssZQTX1tZuyhgkcVMlLKa3vx39CbBG/mb+9U8PJuwX8QNXI1nFrl/1UXWIWiELP b6KgYX+FV0mh5PcY7vBfUmlJ8cv4vrqjyLIIyaPLyEKOJvTTbLQAfPNoHGbINcyC30n+ uklw== 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=3zEq2AfHmzmiP6iMn6OVsjvfYEnKpi8akIlRzP+t4I8=; b=q58pSKX4YtuQ4VLLhwDLqtv/peqddX4iBQ5aM8NGWWdocyeuLe3Cjue+5Twbukjaym 8mSqDyGGJteSm8OyUhYHGs+61L3Qe5/MWTw3Ocdn321wVL5RZN+K76d+5UBT9sCnMV01 MLruE0XPN8Tk6I5vnyCiKD8JkcjW9g8YXuK5T9nuRBm98o91xMb9rT3m6nwC9AZaYWbw U8R6RNxwrlddMReP6bdYiFjgDWFXb4BcIEAVKILex+y4a+SHrpq781vIDjcetzHE9prE LGp8qOdRWgGSgr7uZqB+XaoC8Xei+zqhSPYswoVpsOeRiqMwMJx2rIy6ABd66+/CtbCw etQA== X-Gm-Message-State: AOAM530h4Mf6tGXyzLveVEOjtNPuxvWlroGhSosZZWTbyVc+Twg6zSKD XIbj4FCOz9qXttJB7g1yLR1V0vaS9lu1jj9h X-Google-Smtp-Source: ABdhPJyOLoEwlKV3KvkQhGAg1lxKYQIxIPxhV0ueMTAUdFskUAKjBG6cDkUpWJ/2X1ITIVPBwFiEJQ== X-Received: by 2002:aa7:9099:0:b0:44c:a3b5:ca52 with SMTP id i25-20020aa79099000000b0044ca3b5ca52mr6578798pfa.85.1634829115365; Thu, 21 Oct 2021 08:11:55 -0700 (PDT) Received: from localhost.localdomain ([2406:7400:63:29a4:d874:a949:6890:f95f]) by smtp.gmail.com with ESMTPSA id c9sm5508027pgq.58.2021.10.21.08.11.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Oct 2021 08:11:54 -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, Thomas Petazzoni , =?utf-8?q?Pali_Roh=C3=A1r?= , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , linux-arm-kernel@lists.infradead.org (moderated list:PCI DRIVER FOR AARDVARK (Marvell Armada 3700)) Subject: [PATCH v3 11/25] PCI: aardvark: Remove redundant error fabrication when device read fails Date: Thu, 21 Oct 2021 20:37:36 +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 Reviewed-by: Pali Rohár --- drivers/pci/controller/pci-aardvark.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index 596ebcfcc82d..1af772c76d06 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -893,10 +893,8 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn, u32 reg; int ret; - if (!advk_pcie_valid_device(pcie, bus, devfn)) { - *val = 0xffffffff; + if (!advk_pcie_valid_device(pcie, bus, devfn)) return PCIBIOS_DEVICE_NOT_FOUND; - } if (pci_is_root_bus(bus)) return pci_bridge_emul_conf_read(&pcie->bridge, where, @@ -920,7 +918,6 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn, *val = CFG_RD_CRS_VAL; return PCIBIOS_SUCCESSFUL; } - *val = 0xffffffff; return PCIBIOS_SET_FAILED; } @@ -955,16 +952,13 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn, *val = CFG_RD_CRS_VAL; return PCIBIOS_SUCCESSFUL; } - *val = 0xffffffff; return PCIBIOS_SET_FAILED; } /* Check PIO status and get the read result */ ret = advk_pcie_check_pio_status(pcie, allow_crs, val); - if (ret < 0) { - *val = 0xffffffff; + if (ret < 0) return PCIBIOS_SET_FAILED; - } if (size == 1) *val = (*val >> (8 * (where & 3))) & 0xff;