From patchwork Wed Nov 11 05:43:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Widawsky X-Patchwork-Id: 12187991 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51E16C56201 for ; Wed, 11 Nov 2020 05:44:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 140ED208CA for ; Wed, 11 Nov 2020 05:44:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726082AbgKKFoo (ORCPT ); Wed, 11 Nov 2020 00:44:44 -0500 Received: from mga12.intel.com ([192.55.52.136]:54147 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725903AbgKKFoH (ORCPT ); Wed, 11 Nov 2020 00:44:07 -0500 IronPort-SDR: dZQXnPX+xjfL1fhktFf/tJOXklqPlhAHKJRtFiGnsmlcSw/G7NICG3ImksiXFXcN1scuWa1oaw oTWQrv7t3EoA== X-IronPort-AV: E=McAfee;i="6000,8403,9801"; a="149372960" X-IronPort-AV: E=Sophos;i="5.77,468,1596524400"; d="scan'208";a="149372960" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Nov 2020 21:44:04 -0800 IronPort-SDR: c1yfbGvYRNgmO90XpmPA12ZWBwnjq6m1+Bkili3SSRDGWX+M/E3KT1G3oyVEHRHW5zDBY+xzcI +SL5JSBTHCZA== X-IronPort-AV: E=Sophos;i="5.77,468,1596524400"; d="scan'208";a="360414747" Received: from hccoutan-mobl1.amr.corp.intel.com (HELO bwidawsk-mobl5.local) ([10.252.131.159]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Nov 2020 21:44:04 -0800 From: Ben Widawsky To: linux-cxl@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, Dan Williams , Ira Weiny , Vishal Verma , "Kelley, Sean V" , Bjorn Helgaas , "Rafael J . Wysocki" , Ben Widawsky Subject: [RFC PATCH 3/9] cxl/mem: Add a driver for the type-3 mailbox Date: Tue, 10 Nov 2020 21:43:50 -0800 Message-Id: <20201111054356.793390-4-ben.widawsky@intel.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201111054356.793390-1-ben.widawsky@intel.com> References: <20201111054356.793390-1-ben.widawsky@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org From: Dan Williams The CXL.mem protocol allows a device to act as a provider of "System RAM" and/or "Persistent Memory" that is fully coherent as if the memory was attached to the typical CPU memory controller. The memory range exported by the device may optionally be described by the platform firmware memory map, or by infrastructure like LIBNVDIMM to provision persistent memory capacity from one, or more, CXL.mem devices. A pre-requisite for Linux-managed memory-capacity provisioning is this cxl_mem driver that can speak the "type-3 mailbox" protocol. For now just land the driver boiler-plate and fill it in with functionality in subsequent commits. Signed-off-by: Dan Williams Signed-off-by: Ben Widawsky --- drivers/cxl/Kconfig | 20 +++++++++++ drivers/cxl/Makefile | 2 ++ drivers/cxl/mem.c | 82 ++++++++++++++++++++++++++++++++++++++++++++ drivers/cxl/pci.h | 15 ++++++++ 4 files changed, 119 insertions(+) create mode 100644 drivers/cxl/mem.c create mode 100644 drivers/cxl/pci.h diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig index dd724bd364df..15548f5c77ff 100644 --- a/drivers/cxl/Kconfig +++ b/drivers/cxl/Kconfig @@ -27,4 +27,24 @@ config CXL_ACPI resources described by the CEDT (CXL Early Discovery Table) Say 'y' to enable CXL (Compute Express Link) drivers. + +config CXL_MEM + tristate "CXL.mem Device Support" + depends on PCI && CXL_BUS_PROVIDER != n + default m if CXL_BUS_PROVIDER + help + The CXL.mem protocol allows a device to act as a provider of + "System RAM" and/or "Persistent Memory" that is fully coherent + as if the memory was attached to the typical CPU memory + controller. + + Say 'y/m' to enable a driver named "cxl_mem.ko" that will attach + to CXL.mem devices for configuration, provisioning, and health + monitoring, the so called "type-3 mailbox". Note, this driver + is required for dynamic provisioning of CXL.mem attached + memory, a pre-requisite for persistent memory support, but + devices that provide volatile memory may be fully described by + existing platform firmware memory enumeration. + + If unsure say 'n'. endif diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile index d38cd34a2582..97fdffb00f2d 100644 --- a/drivers/cxl/Makefile +++ b/drivers/cxl/Makefile @@ -1,5 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o +obj-$(CONFIG_CXL_MEM) += cxl_mem.o ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL cxl_acpi-y := acpi.o +cxl_mem-y := mem.o diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c new file mode 100644 index 000000000000..aa7d881fa47b --- /dev/null +++ b/drivers/cxl/mem.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright(c) 2020 Intel Corporation. All rights reserved. +#include +#include +#include +#include "acpi.h" +#include "pci.h" + +struct cxl_mem { + void __iomem *regs; +}; + +static int cxl_mem_dvsec(struct pci_dev *pdev, int dvsec) +{ + int pos; + + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DVSEC); + if (!pos) + return 0; + + while (pos) { + u16 vendor, id; + + pci_read_config_word(pdev, pos + PCI_DVSEC_VENDOR_OFFSET, &vendor); + pci_read_config_word(pdev, pos + PCI_DVSEC_ID_OFFSET, &id); + if (vendor == PCI_DVSEC_VENDOR_CXL && dvsec == id) + return pos; + + pos = pci_find_next_ext_capability(pdev, pos, PCI_EXT_CAP_ID_DVSEC); + } + + return 0; +} + +static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id) +{ + struct device *dev = &pdev->dev; + struct cxl_mem *cxlm; + int rc, regloc; + + rc = cxl_bus_prepared(pdev); + if (rc != 0) { + dev_err(dev, "failed to acquire interface\n"); + return rc; + } + + regloc = cxl_mem_dvsec(pdev, PCI_DVSEC_ID_CXL_REGLOC); + if (!regloc) { + dev_err(dev, "register location dvsec not found\n"); + return -ENXIO; + } + + cxlm = devm_kzalloc(dev, sizeof(*cxlm), GFP_KERNEL); + if (!cxlm) + return -ENOMEM; + + return 0; +} + +static void cxl_mem_remove(struct pci_dev *pdev) +{ +} + +static const struct pci_device_id cxl_mem_pci_tbl[] = { + /* PCI class code for CXL.mem Type-3 Devices */ + { PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, + PCI_CLASS_MEMORY_CXL, 0xffffff, 0 }, + { /* terminate list */ }, +}; +MODULE_DEVICE_TABLE(pci, cxl_mem_pci_tbl); + +static struct pci_driver cxl_mem_driver = { + .name = KBUILD_MODNAME, + .id_table = cxl_mem_pci_tbl, + .probe = cxl_mem_probe, + .remove = cxl_mem_remove, +}; + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Intel Corporation"); +module_pci_driver(cxl_mem_driver); +MODULE_IMPORT_NS(CXL); diff --git a/drivers/cxl/pci.h b/drivers/cxl/pci.h new file mode 100644 index 000000000000..beb03921e6da --- /dev/null +++ b/drivers/cxl/pci.h @@ -0,0 +1,15 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright(c) 2020 Intel Corporation. All rights reserved. +#ifndef __CXL_PCI_H__ +#define __CXL_PCI_H__ + +#define PCI_CLASS_MEMORY_CXL 0x050210 + +#define PCI_EXT_CAP_ID_DVSEC 0x23 +#define PCI_DVSEC_VENDOR_CXL 0x1E98 +#define PCI_DVSEC_VENDOR_OFFSET 0x4 +#define PCI_DVSEC_ID_OFFSET 0x8 +#define PCI_DVSEC_ID_CXL 0x0 +#define PCI_DVSEC_ID_CXL_REGLOC 0x8 + +#endif /* __CXL_PCI_H__ */