From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A461C4332F for ; Fri, 16 Dec 2022 09:36:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229639AbiLPJgk (ORCPT ); Fri, 16 Dec 2022 04:36:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230156AbiLPJge (ORCPT ); Fri, 16 Dec 2022 04:36:34 -0500 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC80D26554 for ; Fri, 16 Dec 2022 01:36:32 -0800 (PST) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4NYP8j3pp1z686Kq; Fri, 16 Dec 2022 17:35:17 +0800 (CST) Received: from localhost (10.45.152.125) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Fri, 16 Dec 2022 09:36:30 +0000 Date: Fri, 16 Dec 2022 09:36:29 +0000 From: Jonathan Cameron To: Dave Jiang CC: , , , , Subject: Re: [PATCH v4] cxl: add RAS status unmasking for CXL Message-ID: <20221216093629.00000b7b@Huawei.com> In-Reply-To: <167112768345.3343090.11728168471813709343.stgit@djiang5-desk3.ch.intel.com> References: <167112768345.3343090.11728168471813709343.stgit@djiang5-desk3.ch.intel.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.45.152.125] X-ClientProxiedBy: lhrpeml500002.china.huawei.com (7.191.160.78) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org On Thu, 15 Dec 2022 11:08:03 -0700 Dave Jiang wrote: > By default the CXL RAS mask registers bits are defaulted to 1's and > suppress all error reporting. If the kernel has negotiated ownership > of error handling for CXL then unmask the mask registers by writing 0s. > > Signed-off-by: Dave Jiang > One trivial comment inline that is up to you. Dan's suggestion makes sense. Reviewed-by: Jonathan Cameron > --- > > Based on patch posted by Ira [1] to export CXL native error reporting control. > > [1]: https://lore.kernel.org/linux-cxl/20221212070627.1372402-2-ira.weiny@intel.com/ > > v4: > - Fix masking of RAS register. (Jonathan) > > v3: > - Remove flex bus port status check. (Jonathan) > - Only unmask known mask bits. (Jonathan) > > v2: > - Add definition of PCI_EXP_LNKSTA2_FLIT. (Dan) > - Return error for cxl_pci_ras_unmask(). (Dan) > - Add dev_dbg() for register bits to be cleared. (Dan) > - Check Flex Port DVSEC status. (Dan) > --- > drivers/cxl/cxl.h | 1 + > drivers/cxl/pci.c | 48 +++++++++++++++++++++++++++++++++++++++++ > include/uapi/linux/pci_regs.h | 1 + > 3 files changed, 50 insertions(+) > > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h > index 1b1cf459ac77..31e795c6d537 100644 > --- a/drivers/cxl/cxl.h > +++ b/drivers/cxl/cxl.h > @@ -130,6 +130,7 @@ static inline int ways_to_eiw(unsigned int ways, u8 *eiw) > #define CXL_RAS_UNCORRECTABLE_STATUS_MASK (GENMASK(16, 14) | GENMASK(11, 0)) > #define CXL_RAS_UNCORRECTABLE_MASK_OFFSET 0x4 > #define CXL_RAS_UNCORRECTABLE_MASK_MASK (GENMASK(16, 14) | GENMASK(11, 0)) > +#define CXL_RAS_UNCORRECTABLE_MASK_F256B_MASK BIT(8) > #define CXL_RAS_UNCORRECTABLE_SEVERITY_OFFSET 0x8 > #define CXL_RAS_UNCORRECTABLE_SEVERITY_MASK (GENMASK(16, 14) | GENMASK(11, 0)) > #define CXL_RAS_CORRECTABLE_STATUS_OFFSET 0xC > diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c > index 33083a522fd1..64272db6a3fd 100644 > --- a/drivers/cxl/pci.c > +++ b/drivers/cxl/pci.c > @@ -419,6 +419,53 @@ static void disable_aer(void *pdev) > pci_disable_pcie_error_reporting(pdev); > } > > +/* > + * CXL v3.0 6.2.3 Table 6-4 > + * The table indicates that if PCIe Flit Mode is set, then CXL is in 256B flits > + * mode, otherwise it's 68B flits mode. > + */ > +static bool cxl_pci_flit_256(struct pci_dev *pdev) > +{ > + u32 lnksta2; > + > + pcie_capability_read_dword(pdev, PCI_EXP_LNKSTA2, &lnksta2); > + return lnksta2 & PCI_EXP_LNKSTA2_FLIT; > +} > + > +static int cxl_pci_ras_unmask(struct pci_dev *pdev) > +{ > + struct pci_host_bridge *host_bridge = pci_find_host_bridge(pdev->bus); > + struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); > + void __iomem *addr; > + u32 val, mask; > + > + if (!cxlds->regs.ras) > + return -ENODEV; > + > + /* BIOS has CXL error control */ > + if (!host_bridge->native_cxl_error) > + return -EOPNOTSUPP; > + > + addr = cxlds->regs.ras + CXL_RAS_UNCORRECTABLE_MASK_OFFSET; > + val = readl(addr); > + dev_dbg(&pdev->dev, "Uncorrectable RAS Errors Mask: %#x\n", val); > + > + mask = CXL_RAS_UNCORRECTABLE_MASK_MASK; > + if (!cxl_pci_flit_256(pdev)) > + mask &= ~CXL_RAS_UNCORRECTABLE_MASK_F256B_MASK; > + val &= ~mask; > + writel(val, addr); > + dev_dbg(&pdev->dev, "Unmasked Uncorrectable RAS Errors Mask: %#x\n", val); > + > + addr = cxlds->regs.ras + CXL_RAS_CORRECTABLE_MASK_OFFSET; > + val = readl(addr); > + dev_dbg(&pdev->dev, "Correctable RAS Errors Mask: %#x\n", val); > + val &= ~CXL_RAS_CORRECTABLE_MASK_MASK; > + writel(val, addr); > + dev_dbg(&pdev->dev, "Unmasked Correctable RAS Errors Mask: %#x\n", val); Real nitpick but I'd like a blank line here as the return isn't related to the previous block of code. > + return 0; > +} > + > static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > { > struct cxl_register_map map; > @@ -498,6 +545,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > > if (cxlds->regs.ras) { > pci_enable_pcie_error_reporting(pdev); > + cxl_pci_ras_unmask(pdev); > rc = devm_add_action_or_reset(&pdev->dev, disable_aer, pdev); > if (rc) > return rc; > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h > index 82a03ea954af..576ee2ec973f 100644 > --- a/include/uapi/linux/pci_regs.h > +++ b/include/uapi/linux/pci_regs.h > @@ -693,6 +693,7 @@ > #define PCI_EXP_LNKCTL2_TX_MARGIN 0x0380 /* Transmit Margin */ > #define PCI_EXP_LNKCTL2_HASD 0x0020 /* HW Autonomous Speed Disable */ > #define PCI_EXP_LNKSTA2 0x32 /* Link Status 2 */ > +#define PCI_EXP_LNKSTA2_FLIT BIT(10) /* Flit Mode Status */ > #define PCI_CAP_EXP_ENDPOINT_SIZEOF_V2 0x32 /* end of v2 EPs w/ link */ > #define PCI_EXP_SLTCAP2 0x34 /* Slot Capabilities 2 */ > #define PCI_EXP_SLTCAP2_IBPD 0x00000001 /* In-band PD Disable Supported */ > >