From nobody Sun Sep 22 15:39:09 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 B93EEC433EF for ; Thu, 18 Nov 2021 14:05:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A067060EFD for ; Thu, 18 Nov 2021 14:05:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232229AbhKROIe (ORCPT ); Thu, 18 Nov 2021 09:08:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232120AbhKROId (ORCPT ); Thu, 18 Nov 2021 09:08:33 -0500 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 972B0C061570; Thu, 18 Nov 2021 06:05:33 -0800 (PST) Received: by mail-pl1-x633.google.com with SMTP id y8so5345759plg.1; Thu, 18 Nov 2021 06:05:33 -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=/1DR3OOSzZuxfUtlUJMZJiGVE0NaIRWqbUvxoOW0jlM=; b=jdSkECp3SP2RSmPMNet1SnMVaDyeo8yKkV5XHhVCvBhepg39GB2PfKzHjI+JTCDOEd guMiR3Jz/cAYlAQZmKlQjSrTuQ9GsLk6ntRuvGW+LNSHWj9DGA+EH+dJZwkDmB0upCqa KoQ/F8hvOOqHkXQTqf7ey2jAwYO4YZd1QWmdlxXb+nJgU7oLMjbGVJrms2xRStItbWqS 3wrwCSjD6xcmyik3lX3vTdmKuYBwqZTqmuUIFJqS/pM6qeS+PreJLe/cVu0HL1hF2qdh Ys5BoxlLTUTsYytDVQhE6LH5h/6F+1Qme6HtPpolIQAk3KfkWJr7PuZ8rVhw5aitmm7D 3+rQ== 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=/1DR3OOSzZuxfUtlUJMZJiGVE0NaIRWqbUvxoOW0jlM=; b=m1fz5SYWXM0MUZcfgbulBam9ih7fRH8ijYzhI/NaD2IVhbPf2GeftplCixadZIwA26 oqBnVlfIwv7Rm3dRMuHXAExf15BNQ7Wg4lJ2DsaaG5Ih1traq+PI0IrsTey83T4b+QF1 lCHbK/1NBxfnbMzlTNIZV1Y4cHsf9FBbFhy6HdTbA2HRkKMPszOMJ16K/eXCixKXtWFP Fye/ISIVbXu/B1HE4R7/KUjZAKsHGAYASwxXTapx0pjfHaL/1x5QvF4NydgcpfBPRCQ+ MSSTJB2zd+Iwoud8qFeGyJYz94tDZoqKMTQalcGhBXkSF6Oox3xHR/2N7sKuRp8pBWX4 hjqA== X-Gm-Message-State: AOAM5317hRrQ5sGwUs3475Fv/riQ8YF2oXFuqzL3xnWwCzJ5gOmOIIs5 JuLk+0wpfXhR9blLGZZ+Q3w= X-Google-Smtp-Source: ABdhPJylY1j0PXT0hDdZWfRI0y02595GqGzG4pRAVnMOmOXr655gaWX9MhLwp3Tgo0soIDQbH4IMtQ== X-Received: by 2002:a17:902:9303:b0:143:d6c7:babc with SMTP id bc3-20020a170902930300b00143d6c7babcmr21577067plb.58.1637244333020; Thu, 18 Nov 2021 06:05:33 -0800 (PST) Received: from localhost.localdomain ([2406:7400:63:2c47:5ffe:fc34:61f0:f1ea]) by smtp.gmail.com with ESMTPSA id x14sm2822878pjl.27.2021.11.18.06.05.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Nov 2021 06:05:32 -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, Robert Richter , Lorenzo Pieralisi , Rob Herring , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , linux-arm-kernel@lists.infradead.org (moderated list:PCIE DRIVER FOR CAVIUM THUNDERX) Subject: [PATCH v4 05/25] PCI: thunder: Remove redundant error fabrication when device read fails Date: Thu, 18 Nov 2021 19:33:15 +0530 Message-Id: <22f471b638276422926c49f3d42ac41bc7b28b3d.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/pci-thunder-ecam.c | 46 ++++++++--------------- drivers/pci/controller/pci-thunder-pem.c | 4 +- 2 files changed, 17 insertions(+), 33 deletions(-) diff --git a/drivers/pci/controller/pci-thunder-ecam.c b/drivers/pci/contro= ller/pci-thunder-ecam.c index e9d5ca245f5e..b5bd10a62adb 100644 --- a/drivers/pci/controller/pci-thunder-ecam.c +++ b/drivers/pci/controller/pci-thunder-ecam.c @@ -41,10 +41,9 @@ static int handle_ea_bar(u32 e0, int bar, struct pci_bus= *bus, } if (where_a =3D=3D 0x4) { addr =3D bus->ops->map_bus(bus, devfn, bar); /* BAR 0 */ - if (!addr) { - *val =3D ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } + v =3D readl(addr); v &=3D ~0xf; v |=3D 2; /* EA entry-1. Base-L */ @@ -56,10 +55,9 @@ static int handle_ea_bar(u32 e0, int bar, struct pci_bus= *bus, u32 barl_rb; =20 addr =3D bus->ops->map_bus(bus, devfn, bar); /* BAR 0 */ - if (!addr) { - *val =3D ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } + barl_orig =3D readl(addr + 0); writel(0xffffffff, addr + 0); barl_rb =3D readl(addr + 0); @@ -72,10 +70,9 @@ static int handle_ea_bar(u32 e0, int bar, struct pci_bus= *bus, } if (where_a =3D=3D 0xc) { addr =3D bus->ops->map_bus(bus, devfn, bar + 4); /* BAR 1 */ - if (!addr) { - *val =3D ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } + v =3D readl(addr); /* EA entry-3. Base-H */ set_val(v, where, size, val); return PCIBIOS_SUCCESSFUL; @@ -104,10 +101,8 @@ static int thunder_ecam_p2_config_read(struct pci_bus = *bus, unsigned int devfn, } =20 addr =3D bus->ops->map_bus(bus, devfn, where_a); - if (!addr) { - *val =3D ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } =20 v =3D readl(addr); =20 @@ -135,10 +130,8 @@ static int thunder_ecam_config_read(struct pci_bus *bu= s, unsigned int devfn, int where_a =3D where & ~3; =20 addr =3D bus->ops->map_bus(bus, devfn, 0xc); - if (!addr) { - *val =3D ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } =20 v =3D readl(addr); =20 @@ -146,10 +139,8 @@ static int thunder_ecam_config_read(struct pci_bus *bu= s, unsigned int devfn, cfg_type =3D (v >> 16) & 0x7f; =20 addr =3D bus->ops->map_bus(bus, devfn, 8); - if (!addr) { - *val =3D ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } =20 class_rev =3D readl(addr); if (class_rev =3D=3D 0xffffffff) @@ -176,10 +167,8 @@ static int thunder_ecam_config_read(struct pci_bus *bu= s, unsigned int devfn, } =20 addr =3D bus->ops->map_bus(bus, devfn, 0); - if (!addr) { - *val =3D ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } =20 vendor_device =3D readl(addr); if (vendor_device =3D=3D 0xffffffff) @@ -196,10 +185,9 @@ static int thunder_ecam_config_read(struct pci_bus *bu= s, unsigned int devfn, bool is_tns =3D (vendor_device =3D=3D 0xa01f177d); =20 addr =3D bus->ops->map_bus(bus, devfn, 0x70); - if (!addr) { - *val =3D ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } + /* E_CAP */ v =3D readl(addr); has_msix =3D (v & 0xff00) !=3D 0; @@ -211,10 +199,9 @@ static int thunder_ecam_config_read(struct pci_bus *bu= s, unsigned int devfn, } if (where_a =3D=3D 0xb0) { addr =3D bus->ops->map_bus(bus, devfn, where_a); - if (!addr) { - *val =3D ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } + v =3D readl(addr); if (v & 0xff00) pr_err("Bad MSIX cap header: %08x\n", v); @@ -268,10 +255,9 @@ static int thunder_ecam_config_read(struct pci_bus *bu= s, unsigned int devfn, =20 if (where_a =3D=3D 0x70) { addr =3D bus->ops->map_bus(bus, devfn, where_a); - if (!addr) { - *val =3D ~0; + if (!addr) return PCIBIOS_DEVICE_NOT_FOUND; - } + v =3D readl(addr); if (v & 0xff00) pr_err("Bad PCIe cap header: %08x\n", v); diff --git a/drivers/pci/controller/pci-thunder-pem.c b/drivers/pci/control= ler/pci-thunder-pem.c index 0660b9da204f..06a9855cb431 100644 --- a/drivers/pci/controller/pci-thunder-pem.c +++ b/drivers/pci/controller/pci-thunder-pem.c @@ -41,10 +41,8 @@ static int thunder_pem_bridge_read(struct pci_bus *bus, = unsigned int devfn, struct pci_config_window *cfg =3D bus->sysdata; struct thunder_pem_pci *pem_pci =3D (struct thunder_pem_pci *)cfg->priv; =20 - if (devfn !=3D 0 || where >=3D 2048) { - *val =3D ~0; + if (devfn !=3D 0 || where >=3D 2048) return PCIBIOS_DEVICE_NOT_FOUND; - } =20 /* * 32-bit accesses only. Write the address to the low order --=20 2.25.1