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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E3D2ECCFA05 for ; Fri, 7 Nov 2025 12:36:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=RNPAjdFUODf1DNYQg5T1DhotSLcFiTR7Emd2m0OL/JM=; b=CPZpuVDCEPDATZBdOXKTuyRGsr bGpXo7pNrahpN5bqA5rRLoMbUD4NqnyBP40PvVxVlDJAXuY2kanOXsV7QQQ2eCyLkFQ57qzXB0NEK aQgjhMT6PaCY2UpJF+wwLA+w/aS6h8/9Fc07ESxT2OELaxe7kp9100OgXyD3mHCQLIuCQ4+ZCTkfl avCAfOSqupKrerdxxFWpZDnYwo3MPXrdekcUmcBhK+dlhGKOSM8KG7PH6icvvm8+s2QRhMKCj6oLS gp6KBCvwXlAhL8DhdRX5PM6gb7psLL/LHVxQTBEr6iqt5InzPs5qqpeV8k9ec+kvZTYBjqkBgXwUy qA034DlQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vHLhZ-0000000HJBg-0PON; Fri, 07 Nov 2025 12:36:25 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vHLhU-0000000HJ7s-2jFh for linux-arm-kernel@lists.infradead.org; Fri, 07 Nov 2025 12:36:23 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 721AB1515; Fri, 7 Nov 2025 04:36:12 -0800 (PST) Received: from e134344.cambridge.arm.com (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 4D2673F66E; Fri, 7 Nov 2025 04:36:15 -0800 (PST) From: Ben Horgan To: james.morse@arm.com Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, bobo.shaobowang@huawei.com, carl@os.amperecomputing.com, catalin.marinas@arm.com, dakr@kernel.org, dave.martin@arm.com, david@redhat.com, dfustini@baylibre.com, fenghuay@nvidia.com, gregkh@linuxfoundation.org, gshan@redhat.com, guohanjun@huawei.com, jeremy.linton@arm.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, lpieralisi@kernel.org, peternewman@google.com, quic_jiles@quicinc.com, rafael@kernel.org, robh@kernel.org, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, sudeep.holla@arm.com, tan.shaopeng@fujitsu.com, will@kernel.org, xhao@linux.alibaba.com, Shaopeng Tan , Ben Horgan Subject: [PATCH 10/33] arm_mpam: Add probe/remove for mpam msc driver and kbuild boiler plate Date: Fri, 7 Nov 2025 12:34:27 +0000 Message-ID: <20251107123450.664001-11-ben.horgan@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251107123450.664001-1-ben.horgan@arm.com> References: <20251107123450.664001-1-ben.horgan@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251107_043622_468009_9392F064 X-CRM114-Status: GOOD ( 29.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: James Morse Probing MPAM is convoluted. MSCs that are integrated with a CPU may only be accessible from those CPUs, and they may not be online. Touching the hardware early is pointless as MPAM can't be used until the system-wide common values for num_partid and num_pmg have been discovered. Start with driver probe/remove and mapping the MSC. CC: Carl Worth Tested-by: Fenghua Yu Tested-by: Shaopeng Tan Tested-by: Peter Newman Signed-off-by: James Morse Signed-off-by: Ben Horgan --- Changes since v3: >From Jonathan: Include cleanup Use devm_mutex_init() Add an ERR_CAST() Fenghua: Return zero from update_msc_accessibility() Additional: Fail probe if MSC doesn't have an MMIO interface --- arch/arm64/Kconfig | 1 + drivers/Kconfig | 2 + drivers/Makefile | 1 + drivers/resctrl/Kconfig | 15 +++ drivers/resctrl/Makefile | 4 + drivers/resctrl/mpam_devices.c | 194 ++++++++++++++++++++++++++++++++ drivers/resctrl/mpam_internal.h | 49 ++++++++ 7 files changed, 266 insertions(+) create mode 100644 drivers/resctrl/Kconfig create mode 100644 drivers/resctrl/Makefile create mode 100644 drivers/resctrl/mpam_devices.c create mode 100644 drivers/resctrl/mpam_internal.h diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index c5e66d5d72cd..004d58cfbff8 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -2025,6 +2025,7 @@ config ARM64_TLB_RANGE config ARM64_MPAM bool "Enable support for MPAM" + select ARM64_MPAM_DRIVER if EXPERT # does nothing yet select ACPI_MPAM if ACPI help Memory System Resource Partitioning and Monitoring (MPAM) is an diff --git a/drivers/Kconfig b/drivers/Kconfig index 4915a63866b0..3054b50a2f4c 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -251,4 +251,6 @@ source "drivers/hte/Kconfig" source "drivers/cdx/Kconfig" +source "drivers/resctrl/Kconfig" + endmenu diff --git a/drivers/Makefile b/drivers/Makefile index 8e1ffa4358d5..20eb17596b89 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -194,6 +194,7 @@ obj-$(CONFIG_HTE) += hte/ obj-$(CONFIG_DRM_ACCEL) += accel/ obj-$(CONFIG_CDX_BUS) += cdx/ obj-$(CONFIG_DPLL) += dpll/ +obj-y += resctrl/ obj-$(CONFIG_DIBS) += dibs/ obj-$(CONFIG_S390) += s390/ diff --git a/drivers/resctrl/Kconfig b/drivers/resctrl/Kconfig new file mode 100644 index 000000000000..ef2f3adf64a9 --- /dev/null +++ b/drivers/resctrl/Kconfig @@ -0,0 +1,15 @@ +menuconfig ARM64_MPAM_DRIVER + bool "MPAM driver" + depends on ARM64 && ARM64_MPAM && EXPERT + help + Memory System Resource Partitioning and Monitoring (MPAM) driver for + System IP, e,g. caches and memory controllers. + +if ARM64_MPAM_DRIVER + +config ARM64_MPAM_DRIVER_DEBUG + bool "Enable debug messages from the MPAM driver" + help + Say yes here to enable debug messages from the MPAM driver. + +endif diff --git a/drivers/resctrl/Makefile b/drivers/resctrl/Makefile new file mode 100644 index 000000000000..898199dcf80d --- /dev/null +++ b/drivers/resctrl/Makefile @@ -0,0 +1,4 @@ +obj-$(CONFIG_ARM64_MPAM_DRIVER) += mpam.o +mpam-y += mpam_devices.o + +ccflags-$(CONFIG_ARM64_MPAM_DRIVER_DEBUG) += -DDEBUG diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c new file mode 100644 index 000000000000..6c6be133d73a --- /dev/null +++ b/drivers/resctrl/mpam_devices.c @@ -0,0 +1,194 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2025 Arm Ltd. + +#define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "mpam_internal.h" + +/* + * mpam_list_lock protects the SRCU lists when writing. Once the + * mpam_enabled key is enabled these lists are read-only, + * unless the error interrupt disables the driver. + */ +static DEFINE_MUTEX(mpam_list_lock); +static LIST_HEAD(mpam_all_msc); + +struct srcu_struct mpam_srcu; + +/* + * Number of MSCs that have been probed. Once all MSC have been probed MPAM + * can be enabled. + */ +static atomic_t mpam_num_msc; + +/* + * An MSC can control traffic from a set of CPUs, but may only be accessible + * from a (hopefully wider) set of CPUs. The common reason for this is power + * management. If all the CPUs in a cluster are in PSCI:CPU_SUSPEND, the + * corresponding cache may also be powered off. By making accesses from + * one of those CPUs, we ensure this isn't the case. + */ +static int update_msc_accessibility(struct mpam_msc *msc) +{ + u32 affinity_id; + int err; + + err = device_property_read_u32(&msc->pdev->dev, "cpu_affinity", + &affinity_id); + if (err) + cpumask_copy(&msc->accessibility, cpu_possible_mask); + else + acpi_pptt_get_cpus_from_container(affinity_id, + &msc->accessibility); + return 0; +} + +static int fw_num_msc; + +static void mpam_msc_destroy(struct mpam_msc *msc) +{ + struct platform_device *pdev = msc->pdev; + + lockdep_assert_held(&mpam_list_lock); + + list_del_rcu(&msc->all_msc_list); + platform_set_drvdata(pdev, NULL); +} + +static void mpam_msc_drv_remove(struct platform_device *pdev) +{ + struct mpam_msc *msc = platform_get_drvdata(pdev); + + if (!msc) + return; + + mutex_lock(&mpam_list_lock); + mpam_msc_destroy(msc); + mutex_unlock(&mpam_list_lock); + + synchronize_srcu(&mpam_srcu); +} + +static struct mpam_msc *do_mpam_msc_drv_probe(struct platform_device *pdev) +{ + int err; + u32 tmp; + struct mpam_msc *msc; + struct resource *msc_res; + struct device *dev = &pdev->dev; + + lockdep_assert_held(&mpam_list_lock); + + msc = devm_kzalloc(&pdev->dev, sizeof(*msc), GFP_KERNEL); + if (!msc) + return ERR_PTR(-ENOMEM); + + err = devm_mutex_init(dev, &msc->probe_lock); + if (err) + return ERR_PTR(err); + err = devm_mutex_init(dev, &msc->part_sel_lock); + if (err) + return ERR_PTR(err); + msc->id = pdev->id; + msc->pdev = pdev; + INIT_LIST_HEAD_RCU(&msc->all_msc_list); + INIT_LIST_HEAD_RCU(&msc->ris); + + err = update_msc_accessibility(msc); + if (err) + return ERR_PTR(err); + if (cpumask_empty(&msc->accessibility)) { + dev_err_once(dev, "MSC is not accessible from any CPU!"); + return ERR_PTR(-EINVAL); + } + + if (device_property_read_u32(&pdev->dev, "pcc-channel", &tmp)) + msc->iface = MPAM_IFACE_MMIO; + else + msc->iface = MPAM_IFACE_PCC; + + if (msc->iface == MPAM_IFACE_MMIO) { + void __iomem *io; + + io = devm_platform_get_and_ioremap_resource(pdev, 0, + &msc_res); + if (IS_ERR(io)) { + dev_err_once(dev, "Failed to map MSC base address\n"); + return ERR_CAST(io); + } + msc->mapped_hwpage_sz = msc_res->end - msc_res->start; + msc->mapped_hwpage = io; + } else { + return ERR_PTR(-ENOENT); + } + + list_add_rcu(&msc->all_msc_list, &mpam_all_msc); + platform_set_drvdata(pdev, msc); + + return msc; +} + +static int mpam_msc_drv_probe(struct platform_device *pdev) +{ + int err; + struct mpam_msc *msc = NULL; + void *plat_data = pdev->dev.platform_data; + + mutex_lock(&mpam_list_lock); + msc = do_mpam_msc_drv_probe(pdev); + mutex_unlock(&mpam_list_lock); + if (!IS_ERR(msc)) { + /* Create RIS entries described by firmware */ + err = acpi_mpam_parse_resources(msc, plat_data); + if (err) + mpam_msc_drv_remove(pdev); + } else { + err = PTR_ERR(msc); + } + + if (!err && atomic_add_return(1, &mpam_num_msc) == fw_num_msc) + pr_info("Discovered all MSC\n"); + + return err; +} + +static struct platform_driver mpam_msc_driver = { + .driver = { + .name = "mpam_msc", + }, + .probe = mpam_msc_drv_probe, + .remove = mpam_msc_drv_remove, +}; + +static int __init mpam_msc_driver_init(void) +{ + if (!system_supports_mpam()) + return -EOPNOTSUPP; + + init_srcu_struct(&mpam_srcu); + + fw_num_msc = acpi_mpam_count_msc(); + + if (fw_num_msc <= 0) { + pr_err("No MSC devices found in firmware\n"); + return -EINVAL; + } + + return platform_driver_register(&mpam_msc_driver); +} +subsys_initcall(mpam_msc_driver_init); diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h new file mode 100644 index 000000000000..540066903eca --- /dev/null +++ b/drivers/resctrl/mpam_internal.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +// Copyright (C) 2025 Arm Ltd. + +#ifndef MPAM_INTERNAL_H +#define MPAM_INTERNAL_H + +#include +#include +#include +#include +#include + +struct platform_device; + +struct mpam_msc { + /* member of mpam_all_msc */ + struct list_head all_msc_list; + + int id; + struct platform_device *pdev; + + /* Not modified after mpam_is_enabled() becomes true */ + enum mpam_msc_iface iface; + u32 nrdy_usec; + cpumask_t accessibility; + + /* + * probe_lock is only taken during discovery. After discovery these + * properties become read-only and the lists are protected by SRCU. + */ + struct mutex probe_lock; + unsigned long ris_idxs; + u32 ris_max; + + /* mpam_msc_ris of this component */ + struct list_head ris; + + /* + * part_sel_lock protects access to the MSC hardware registers that are + * affected by MPAMCFG_PART_SEL. (including the ID registers that vary + * by RIS). + * If needed, take msc->probe_lock first. + */ + struct mutex part_sel_lock; + + void __iomem *mapped_hwpage; + size_t mapped_hwpage_sz; +}; +#endif /* MPAM_INTERNAL_H */ -- 2.43.0