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 X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 88763C64E7A for ; Tue, 17 Nov 2020 14:33:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A10D2223D for ; Tue, 17 Nov 2020 14:33:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731801AbgKQOci (ORCPT ); Tue, 17 Nov 2020 09:32:38 -0500 Received: from mail-oi1-f195.google.com ([209.85.167.195]:43564 "EHLO mail-oi1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731006AbgKQOcb (ORCPT ); Tue, 17 Nov 2020 09:32:31 -0500 Received: by mail-oi1-f195.google.com with SMTP id t143so22699105oif.10; Tue, 17 Nov 2020 06:32:29 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=0xzVmVMNo5H9yrKMduWNe+xpelp4jIHck9Q/aKCYsek=; b=OPfT+pSxqHGjW4/ReEujozycOe1c53H+N4St6WPl6HbdzhgbpYj0Zp2ibTphAG13zt yg+BxUoNp0cCw9GWFopJM16AP+o9ajYkgDmRnk7VYjHnavhukvBFd5kSOoYLbQEieE+d mgyRmy7ZDcmKXqFzURFyPz4f50sCBRkRcHY58jj5SC++4NswhiqjuJ35nflczCpI6Gvy ZKlu8CZn0jeXZNAZpPplzaNft+GvJUyHilPMoAuCuBmwKuoTu0nwYd7Ru+yyckvV5b4n RmgB300jHZHL1hdvHG4PQa2arhqzKwebPGrpkqTbVGedKFhLiI2byJBDc2W68gwzxfPQ ZxpA== X-Gm-Message-State: AOAM531sYKA+IsUFoNvik+tdtajb00AmRzq3KadBYhWlTF4z2wqFowTK 8A43KNffQHqtdtHl4lFpWG/bUYVMItrc9hRWxrE9AWgoWqA= X-Google-Smtp-Source: ABdhPJxuiY2PL3KCvrF69XkvJyL2Db6xtdBuM0ub2Q0zsrbjKMZD+0KCsQADVrL3t5lT0cqYZllF7be5Hv3c/W9ZWyI= X-Received: by 2002:aca:c4c9:: with SMTP id u192mr2498947oif.69.1605623549108; Tue, 17 Nov 2020 06:32:29 -0800 (PST) MIME-Version: 1.0 References: <20201111054356.793390-1-ben.widawsky@intel.com> <20201111054356.793390-2-ben.widawsky@intel.com> In-Reply-To: <20201111054356.793390-2-ben.widawsky@intel.com> From: "Rafael J. Wysocki" Date: Tue, 17 Nov 2020 15:32:17 +0100 Message-ID: Subject: Re: [RFC PATCH 1/9] cxl/acpi: Add an acpi_cxl module for the CXL interconnect To: Ben Widawsky Cc: linux-cxl@vger.kernel.org, Linux Kernel Mailing List , Linux PCI , ACPI Devel Maling List , Dan Williams , Ira Weiny , Vishal Verma , "Kelley, Sean V" , Bjorn Helgaas , "Rafael J . Wysocki" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org On Wed, Nov 11, 2020 at 6:45 AM Ben Widawsky wrote: > > From: Vishal Verma > > Add an acpi_cxl module to coordinate the ACPI portions of the CXL > (Compute eXpress Link) interconnect. This driver binds to ACPI0017 > objects in the ACPI tree, and coordinates access to the resources > provided by the ACPI CEDT (CXL Early Discovery Table). > > It also coordinates operations of the root port _OSC object to notify > platform firmware that the OS has native support for the CXL > capabilities of endpoints. > > Note: the actbl1.h changes are speculative. The expectation is that they > will arrive through the ACPICA tree in due time. > > Cc: Ben Widawsky > Cc: Dan Williams > Signed-off-by: Vishal Verma > Signed-off-by: Ben Widawsky > --- > drivers/Kconfig | 1 + > drivers/Makefile | 1 + > drivers/cxl/Kconfig | 30 +++++++++++ > drivers/cxl/Makefile | 5 ++ > drivers/cxl/acpi.c | 119 ++++++++++++++++++++++++++++++++++++++++++ > drivers/cxl/acpi.h | 15 ++++++ > include/acpi/actbl1.h | 52 ++++++++++++++++++ > 7 files changed, 223 insertions(+) > create mode 100644 drivers/cxl/Kconfig > create mode 100644 drivers/cxl/Makefile > create mode 100644 drivers/cxl/acpi.c > create mode 100644 drivers/cxl/acpi.h > > diff --git a/drivers/Kconfig b/drivers/Kconfig > index dcecc9f6e33f..62c753a73651 100644 > --- a/drivers/Kconfig > +++ b/drivers/Kconfig > @@ -6,6 +6,7 @@ menu "Device Drivers" > source "drivers/amba/Kconfig" > source "drivers/eisa/Kconfig" > source "drivers/pci/Kconfig" > +source "drivers/cxl/Kconfig" > source "drivers/pcmcia/Kconfig" > source "drivers/rapidio/Kconfig" > > diff --git a/drivers/Makefile b/drivers/Makefile > index c0cd1b9075e3..5dad349de73b 100644 > --- a/drivers/Makefile > +++ b/drivers/Makefile > @@ -73,6 +73,7 @@ obj-$(CONFIG_NVM) += lightnvm/ > obj-y += base/ block/ misc/ mfd/ nfc/ > obj-$(CONFIG_LIBNVDIMM) += nvdimm/ > obj-$(CONFIG_DAX) += dax/ > +obj-$(CONFIG_CXL_BUS) += cxl/ > obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf/ > obj-$(CONFIG_NUBUS) += nubus/ > obj-y += macintosh/ > diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig > new file mode 100644 > index 000000000000..dd724bd364df > --- /dev/null > +++ b/drivers/cxl/Kconfig > @@ -0,0 +1,30 @@ > +# SPDX-License-Identifier: GPL-2.0-only > +menuconfig CXL_BUS > + tristate "CXL (Compute Express Link) Devices Support" > + help > + CXL is a bus that is electrically compatible with PCI-E, but layers > + three protocols on that signalling (CXL.io, CXL.cache, and CXL.mem). The > + CXL.cache protocol allows devices to hold cachelines locally, the > + CXL.mem protocol allows devices to be fully coherent memory targets, the > + CXL.io protocol is equivalent to PCI-E. Say 'y' to enable support for > + the configuration and management of devices supporting these protocols. > + > +if CXL_BUS > + > +config CXL_BUS_PROVIDER > + tristate > + > +config CXL_ACPI > + tristate "CXL Platform Support" > + depends on ACPI > + default CXL_BUS > + select CXL_BUS_PROVIDER > + help > + CXL Platform Support is a prerequisite for any CXL device driver that > + wants to claim ownership of the component register space. By default > + platform firmware assumes Linux is unaware of CXL capabilities and > + requires explicit opt-in. This platform component also mediates > + resources described by the CEDT (CXL Early Discovery Table) > + > + Say 'y' to enable CXL (Compute Express Link) drivers. > +endif > diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile > new file mode 100644 > index 000000000000..d38cd34a2582 > --- /dev/null > +++ b/drivers/cxl/Makefile > @@ -0,0 +1,5 @@ > +# SPDX-License-Identifier: GPL-2.0 > +obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o > + > +ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL > +cxl_acpi-y := acpi.o > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c > new file mode 100644 > index 000000000000..26e4f73838a7 > --- /dev/null > +++ b/drivers/cxl/acpi.c > @@ -0,0 +1,119 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright(c) 2020 Intel Corporation. All rights reserved. > + */ > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include "acpi.h" > + > +static void acpi_cxl_desc_init(struct acpi_cxl_desc *acpi_desc, struct device *dev) > +{ > + dev_set_drvdata(dev, acpi_desc); > + acpi_desc->dev = dev; > +} > + > +static void acpi_cedt_put_table(void *table) > +{ > + acpi_put_table(table); > +} > + > +static int acpi_cxl_add(struct acpi_device *adev) > +{ > + struct acpi_cxl_desc *acpi_desc; > + struct device *dev = &adev->dev; > + struct acpi_table_header *tbl; > + acpi_status status = AE_OK; > + acpi_size sz; > + int rc = 0; > + > + status = acpi_get_table(ACPI_SIG_CEDT, 0, &tbl); > + if (ACPI_FAILURE(status)) { > + dev_err(dev, "failed to find CEDT at startup\n"); > + return 0; > + } > + > + rc = devm_add_action_or_reset(dev, acpi_cedt_put_table, tbl); > + if (rc) > + return rc; > + sz = tbl->length; > + dev_info(dev, "found CEDT at startup: %lld bytes\n", sz); > + > + acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL); > + if (!acpi_desc) > + return -ENOMEM; > + acpi_cxl_desc_init(acpi_desc, &adev->dev); > + > + acpi_desc->acpi_header = *tbl; > + > + return 0; > +} > + > +static int acpi_cxl_remove(struct acpi_device *adev) > +{ > + return 0; > +} > + > +static const struct acpi_device_id acpi_cxl_ids[] = { > + { "ACPI0017", 0 }, > + { "", 0 }, > +}; > +MODULE_DEVICE_TABLE(acpi, acpi_cxl_ids); > + > +static struct acpi_driver acpi_cxl_driver = { First of all, no new acpi_driver instances, pretty please! acpi_default_enumeration() should create a platform device with the ACPI0017 ID for you. Can't you provide a driver for this one? > + .name = KBUILD_MODNAME, > + .ids = acpi_cxl_ids, > + .ops = { > + .add = acpi_cxl_add, > + .remove = acpi_cxl_remove, > + }, > +}; > + > +/* > + * If/when CXL support is defined by other platform firmware the kernel > + * will need a mechanism to select between the platform specific version > + * of this routine, until then, hard-code ACPI assumptions > + */ > +int cxl_bus_prepared(struct pci_dev *pdev) > +{ > + struct acpi_device *adev; > + struct pci_dev *root_port; > + struct device *root; > + > + root_port = pcie_find_root_port(pdev); > + if (!root_port) > + return -ENXIO; > + > + root = root_port->dev.parent; > + if (!root) > + return -ENXIO; > + > + adev = ACPI_COMPANION(root); > + if (!adev) > + return -ENXIO; > + > + /* TODO: OSC enabling */ > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(cxl_bus_prepared); > + > +static __init int acpi_cxl_init(void) > +{ > + return acpi_bus_register_driver(&acpi_cxl_driver); > +} > + > +static __exit void acpi_cxl_exit(void) > +{ > + acpi_bus_unregister_driver(&acpi_cxl_driver); > +} > + > +module_init(acpi_cxl_init); > +module_exit(acpi_cxl_exit); > +MODULE_LICENSE("GPL v2"); > +MODULE_AUTHOR("Intel Corporation"); > diff --git a/drivers/cxl/acpi.h b/drivers/cxl/acpi.h > new file mode 100644 > index 000000000000..011505475cc6 > --- /dev/null > +++ b/drivers/cxl/acpi.h > @@ -0,0 +1,15 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +// Copyright(c) 2020 Intel Corporation. All rights reserved. > + > +#ifndef __CXL_ACPI_H__ > +#define __CXL_ACPI_H__ > +#include > + > +struct acpi_cxl_desc { > + struct acpi_table_header acpi_header; > + struct device *dev; > +}; > + > +int cxl_bus_prepared(struct pci_dev *pci_dev); > + > +#endif /* __CXL_ACPI_H__ */ > diff --git a/include/acpi/actbl1.h b/include/acpi/actbl1.h > index 43549547ed3e..70f745f526e3 100644 > --- a/include/acpi/actbl1.h > +++ b/include/acpi/actbl1.h > @@ -28,6 +28,7 @@ > #define ACPI_SIG_BERT "BERT" /* Boot Error Record Table */ > #define ACPI_SIG_BGRT "BGRT" /* Boot Graphics Resource Table */ > #define ACPI_SIG_BOOT "BOOT" /* Simple Boot Flag Table */ > +#define ACPI_SIG_CEDT "CEDT" /* CXL Early Discovery Table */ > #define ACPI_SIG_CPEP "CPEP" /* Corrected Platform Error Polling table */ > #define ACPI_SIG_CSRT "CSRT" /* Core System Resource Table */ > #define ACPI_SIG_DBG2 "DBG2" /* Debug Port table type 2 */ > @@ -1624,6 +1625,57 @@ struct acpi_ibft_target { > u16 reverse_chap_secret_offset; > }; > > +/******************************************************************************* > + * > + * CEDT - CXL Early Discovery Table (ACPI 6.4) > + * Version 1 > + * > + ******************************************************************************/ > + > +struct acpi_table_cedt { > + struct acpi_table_header header; /* Common ACPI table header */ > + u32 reserved; > +}; > + > +/* Values for CEDT structure types */ > + > +enum acpi_cedt_type { > + ACPI_CEDT_TYPE_HOST_BRIDGE = 0, /* CHBS - CXL Host Bridge Structure */ > + ACPI_CEDT_TYPE_CFMWS = 1, /* CFMWS - CXL Fixed Memory Window Structure */ > +}; > + > +struct acpi_cedt_structure { > + u8 type; > + u8 reserved; > + u16 length; > +}; > + > +/* > + * CEDT Structures, correspond to Type in struct acpi_cedt_structure > + */ > + > +/* 0: CXL Host Bridge Structure */ > + > +struct acpi_cedt_chbs { > + struct acpi_cedt_structure header; > + u32 uid; > + u32 version; > + u32 reserved1; > + u64 base; > + u32 length; > + u32 reserved2; > +}; > + > +/* Values for version field above */ > + > +#define ACPI_CEDT_CHBS_VERSION_CXL11 (0) > +#define ACPI_CEDT_CHBS_VERSION_CXL20 (1) > + > +/* Values for length field above */ > + > +#define ACPI_CEDT_CHBS_LENGTH_CXL11 (0x2000) > +#define ACPI_CEDT_CHBS_LENGTH_CXL20 (0x10000) > + > /* Reset to default packing */ > > #pragma pack() > -- > 2.29.2 >