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 3AD3FCAC5B0 for ; Fri, 3 Oct 2025 00:59:08 +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: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=AIluKvUIeE/qbH8NmvnsgQ/Z6TBiua3Vl8s1i99/pgU=; b=qkueBIvft9oIDdsTgW9pP6kvqf X+fwpCh3QA9lwx4o+KWtLuErt9B5atKrfZzVrHcuxs67m5rscs5jhcX3g8NVZShI4MCZPX6ISoPGU ixJrF94ktj69FFXw7M1zoXP2tycV7zCyC7q6llcQ8tm0z33wXgaHkmTMA0Cy4y6K7SfItGG8BLyq6 DmA9Avt2dHGY72TVbcwZGnPiQEHloZ1Y0NFNAMnv27imi9+tY+Hn5LC0H9OHq3L6qtOZNObecIHNh LF7/uydmlVUuq4jvJk2ozyvXYvRIbOSP7NO46CuNFfQGcAnoUtl/bjiQqsTs5/CvVv/0yj2d7ci7N X5QNzxXA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v4U8S-0000000BTWG-2RgY; Fri, 03 Oct 2025 00:59:00 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v4U8Q-0000000BTVs-0CA4 for linux-arm-kernel@lists.infradead.org; Fri, 03 Oct 2025 00:58:59 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1759453136; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AIluKvUIeE/qbH8NmvnsgQ/Z6TBiua3Vl8s1i99/pgU=; b=bEqfIyFKl2v990Aw75j7FGHxyjM1yXs334ndKzrYk7EIO+NpLZFm8kBgbpDoqUAtFswzMx s0PXd2BQpX4yhyoL+cgQRbqh/3g8RPc3SCIpSUO5+sYRrmoFQOjnjU3RgepkGfbOdiaMrP 3t3qr98UpZYR56TzSBrF9bJ5dWGQa3A= Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-605--QVcGkc6OeeKr3KwNcqW5g-1; Thu, 02 Oct 2025 20:58:55 -0400 X-MC-Unique: -QVcGkc6OeeKr3KwNcqW5g-1 X-Mimecast-MFC-AGG-ID: -QVcGkc6OeeKr3KwNcqW5g_1759453134 Received: by mail-pl1-f198.google.com with SMTP id d9443c01a7336-26e4fcc744dso10586195ad.3 for ; Thu, 02 Oct 2025 17:58:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759453134; x=1760057934; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=AIluKvUIeE/qbH8NmvnsgQ/Z6TBiua3Vl8s1i99/pgU=; b=px/4fGTm2tNR1kPBixncRDNCjUSCH8aYNoayeFki3K4/LVdSG7QIQnOWU5vrN2+AfU KwxF0Pbq3NJrEeFg8BgaBGoeZrx2HKMwcqNfRNhX2DWDJu7ukfLlSHv05GGbP2qdT2gJ /wXEk54QGZntI1nV9SESkaJBHqAFcueKwzT5Vu71NcecSU96vJ4vHMKO+di3OpCIKBqD MeIyIPF747Urga+vsiIrHU8cabeokJqxsZ5ZcNTVMdX5q9a5n6+KGLzAWMnlHunf/608 k1BAmV5BB/Ps22jgspx98DknyyNlMCJwS5d8C7AB6ZlBSBmbxGiqbeIe4R/zggpYCl56 k3QA== X-Forwarded-Encrypted: i=1; AJvYcCUA8xD7HKMXNgxU+KWnHAOwqd8wYrdmqzNzqucptgSf1Gmpzw+NXQBQDrF5MWqwGAqMndpokTujRAiLhom0jner@lists.infradead.org X-Gm-Message-State: AOJu0YzAtlO/GgD14XOelE3fOh8QExVP726hczRee1i33yt1HMrDLICA C0/E+E8qn4X1h6XuycbzWtVi7WwJEZ9V1eY+0ksxYuACNlUthnphHe6gJGVCJIp/5ccyc147aTQ zTy1hch0yry12PA/v1FeHG8ZWRgmqHEleyUnTfiiDwmNOmPXxu2OL4zUKn7FLihnFJa3/uk9bfF oH X-Gm-Gg: ASbGncufMV+kOg3OGGBT0116kgfYhDpATiA3cUnZaYKGZtuTvOLEI2bDLmgtiPX/HYR SwcyJ/eiMv2o0JjOikMVo7IIPquTg+jzD5H/kpJ3Lr++ox682wOIUP5Te+mqKrG2ifrYZYkozEj 8R0QGpsXGFIp0LWi+HgXqSrQXRe788G6voglSDXTEyJD0zw8u43ZOh9N97ke+oEZvujlE3FViXw d6iUwwgy+kWLz3Df13m+4INlwWkiwYeAwKKrjV6p9s8DQA7cSiFfK6Psq7jiEyVN76yVwAv+hMW y1uGyQzNRhii1fA4xke+qz1ai6BhBrM6nyKT2XLt4V0Cv58Pv2HaBKJaTsOqipYOvTu0kFATw2c 0vL+SGvpxFA== X-Received: by 2002:a17:903:230a:b0:282:ee0e:5991 with SMTP id d9443c01a7336-28e9a5f7222mr12696955ad.30.1759453134209; Thu, 02 Oct 2025 17:58:54 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEaTEg5vD3QN8t3LUlZUTp2tkCic8On/odh9gyv30BwyKNn3A3xfpDioQ3VMbjbnGLOYln37A== X-Received: by 2002:a17:903:230a:b0:282:ee0e:5991 with SMTP id d9443c01a7336-28e9a5f7222mr12696725ad.30.1759453133677; Thu, 02 Oct 2025 17:58:53 -0700 (PDT) Received: from [192.168.68.51] (n175-34-62-5.mrk21.qld.optusnet.com.au. [175.34.62.5]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-28e8d1b845bsm32909455ad.79.2025.10.02.17.58.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 02 Oct 2025 17:58:53 -0700 (PDT) Message-ID: <64105db5-01e3-44ba-bfb0-6524de471ccb@redhat.com> Date: Fri, 3 Oct 2025 10:58:40 +1000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 06/29] ACPI / MPAM: Parse the MPAM table To: James Morse , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org Cc: D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Dave Martin , Koba Ko , Shanker Donthineni , fenghuay@nvidia.com, baisheng.gao@unisoc.com, Jonathan Cameron , Rob Herring , Rohit Mathew , Rafael Wysocki , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich References: <20250910204309.20751-1-james.morse@arm.com> <20250910204309.20751-7-james.morse@arm.com> From: Gavin Shan In-Reply-To: <20250910204309.20751-7-james.morse@arm.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 9bKwnpTIqhBV3OUw9CQ2ubNRlW_ur1tceMQ2KIiZUDs_1759453134 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251002_175858_248192_EEBE3336 X-CRM114-Status: GOOD ( 38.18 ) 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 On 9/11/25 6:42 AM, James Morse wrote: > Add code to parse the arm64 specific MPAM table, looking up the cache > level from the PPTT and feeding the end result into the MPAM driver. > > For now the MPAM hook mpam_ris_create() is stubbed out, but will update > the MPAM driver with optional discovered data. > > CC: Carl Worth > Link: https://developer.arm.com/documentation/den0065/3-0bet/?lang=en > Signed-off-by: James Morse > > --- > Changes since v1: > * Whitespace. > * Gave GLOBAL_AFFINITY a pre-processor'd name. > * Fixed assumption that there are zero functional dependencies. > * Bounds check walking of the MSC RIS. > * More bounds checking in the main table walk. > * Check for nonsense numbers of function dependencies. > * Smattering of pr_debug() to help folk feeding line-noise to the parser. > * Changed the comment flavour on the SPDX string. > * Removed additional table check. > * More comment wrangling. > > Changes since RFC: > * Used DEFINE_RES_IRQ_NAMED() and friends macros. > * Additional error handling. > * Check for zero sized MSC. > * Allow table revisions greater than 1. (no spec for revision 0!) > * Use cleanup helpers to retrive ACPI tables, which allows some functions > to be folded together. > --- > arch/arm64/Kconfig | 1 + > drivers/acpi/arm64/Kconfig | 3 + > drivers/acpi/arm64/Makefile | 1 + > drivers/acpi/arm64/mpam.c | 361 ++++++++++++++++++++++++++++++++++++ > drivers/acpi/tables.c | 2 +- > include/linux/acpi.h | 12 ++ > include/linux/arm_mpam.h | 48 +++++ > 7 files changed, 427 insertions(+), 1 deletion(-) > create mode 100644 drivers/acpi/arm64/mpam.c > create mode 100644 include/linux/arm_mpam.h > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 4be8a13505bf..6487c511bdc6 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -2062,6 +2062,7 @@ config ARM64_TLB_RANGE > > config ARM64_MPAM > bool "Enable support for MPAM" > + select ACPI_MPAM if ACPI > help > Memory System Resource Partitioning and Monitoring (MPAM) is an > optional extension to the Arm architecture that allows each > diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig > index b3ed6212244c..f2fd79f22e7d 100644 > --- a/drivers/acpi/arm64/Kconfig > +++ b/drivers/acpi/arm64/Kconfig > @@ -21,3 +21,6 @@ config ACPI_AGDI > > config ACPI_APMT > bool > + > +config ACPI_MPAM > + bool > diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile > index 05ecde9eaabe..9390b57cb564 100644 > --- a/drivers/acpi/arm64/Makefile > +++ b/drivers/acpi/arm64/Makefile > @@ -4,6 +4,7 @@ obj-$(CONFIG_ACPI_APMT) += apmt.o > obj-$(CONFIG_ACPI_FFH) += ffh.o > obj-$(CONFIG_ACPI_GTDT) += gtdt.o > obj-$(CONFIG_ACPI_IORT) += iort.o > +obj-$(CONFIG_ACPI_MPAM) += mpam.o > obj-$(CONFIG_ACPI_PROCESSOR_IDLE) += cpuidle.o > obj-$(CONFIG_ARM_AMBA) += amba.o > obj-y += dma.o init.o > diff --git a/drivers/acpi/arm64/mpam.c b/drivers/acpi/arm64/mpam.c > new file mode 100644 > index 000000000000..fd9cfa143676 > --- /dev/null > +++ b/drivers/acpi/arm64/mpam.c > @@ -0,0 +1,361 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// Copyright (C) 2025 Arm Ltd. > + > +/* Parse the MPAM ACPI table feeding the discovered nodes into the driver */ > + > +#define pr_fmt(fmt) "ACPI MPAM: " fmt > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include > + > +/* > + * Flags for acpi_table_mpam_msc.*_interrupt_flags. > + * See 2.1.1 Interrupt Flags, Table 5, of DEN0065B_MPAM_ACPI_3.0-bet. > + */ > +#define ACPI_MPAM_MSC_IRQ_MODE_MASK BIT(0) > +#define ACPI_MPAM_MSC_IRQ_TYPE_MASK GENMASK(2, 1) > +#define ACPI_MPAM_MSC_IRQ_TYPE_WIRED 0 > +#define ACPI_MPAM_MSC_IRQ_AFFINITY_PROCESSOR_CONTAINER BIT(3) > +#define ACPI_MPAM_MSC_IRQ_AFFINITY_VALID BIT(4) > + > +static bool acpi_mpam_register_irq(struct platform_device *pdev, int intid, > + u32 flags, int *irq, > + u32 processor_container_uid) > +{ > + int sense; > + > + if (!intid) > + return false; > + > + if (FIELD_GET(ACPI_MPAM_MSC_IRQ_TYPE_MASK, flags) != > + ACPI_MPAM_MSC_IRQ_TYPE_WIRED) > + return false; > + > + sense = FIELD_GET(ACPI_MPAM_MSC_IRQ_MODE_MASK, flags); > + > + if (16 <= intid && intid < 32 && processor_container_uid != GLOBAL_AFFINITY) { > + pr_err_once("Partitioned interrupts not supported\n"); > + return false; > + } > + > + *irq = acpi_register_gsi(&pdev->dev, intid, sense, ACPI_ACTIVE_HIGH); > + if (*irq <= 0) { > + pr_err_once("Failed to register interrupt 0x%x with ACPI\n", > + intid); > + return false; > + } > + > + return true; > +} 0 is allowed by acpi_register_gsi(). if (*irq < 0) { pr_err_once(...); return false; } > + > +static void acpi_mpam_parse_irqs(struct platform_device *pdev, > + struct acpi_mpam_msc_node *tbl_msc, > + struct resource *res, int *res_idx) > +{ > + u32 flags, aff; > + int irq; > + > + flags = tbl_msc->overflow_interrupt_flags; > + if (flags & ACPI_MPAM_MSC_IRQ_AFFINITY_VALID && > + flags & ACPI_MPAM_MSC_IRQ_AFFINITY_PROCESSOR_CONTAINER) > + aff = tbl_msc->overflow_interrupt_affinity; > + else > + aff = GLOBAL_AFFINITY; > + if (acpi_mpam_register_irq(pdev, tbl_msc->overflow_interrupt, flags, &irq, aff)) > + res[(*res_idx)++] = DEFINE_RES_IRQ_NAMED(irq, "overflow"); > + > + flags = tbl_msc->error_interrupt_flags; > + if (flags & ACPI_MPAM_MSC_IRQ_AFFINITY_VALID && > + flags & ACPI_MPAM_MSC_IRQ_AFFINITY_PROCESSOR_CONTAINER) > + aff = tbl_msc->error_interrupt_affinity; > + else > + aff = GLOBAL_AFFINITY; > + if (acpi_mpam_register_irq(pdev, tbl_msc->error_interrupt, flags, &irq, aff)) > + res[(*res_idx)++] = DEFINE_RES_IRQ_NAMED(irq, "error"); > +} > + > +static int acpi_mpam_parse_resource(struct mpam_msc *msc, > + struct acpi_mpam_resource_node *res) > +{ > + int level, nid; > + u32 cache_id; > + > + switch (res->locator_type) { > + case ACPI_MPAM_LOCATION_TYPE_PROCESSOR_CACHE: > + cache_id = res->locator.cache_locator.cache_reference; > + level = find_acpi_cache_level_from_id(cache_id); > + if (level <= 0) { > + pr_err_once("Bad level (%u) for cache with id %u\n", level, cache_id); > + return -EINVAL; > + } > + return mpam_ris_create(msc, res->ris_index, MPAM_CLASS_CACHE, > + level, cache_id); > + case ACPI_MPAM_LOCATION_TYPE_MEMORY: > + nid = pxm_to_node(res->locator.memory_locator.proximity_domain); > + if (nid == NUMA_NO_NODE) > + nid = 0; > + return mpam_ris_create(msc, res->ris_index, MPAM_CLASS_MEMORY, > + 255, nid); It's perhaps worthy a warning message when @nid is explicitly set to zero due to the bad proximity domain, something like below. if (nid == NUMA_NO_NODE) { nid = 0; if (num_possible_nodes() > 1) { pr_warn("Bad proximity domain %d, mapped to node 0\n", res->locator.memory_locator.proximity_domain); } } > + default: > + /* These get discovered later and treated as unknown */ > + return 0; > + } > +} > + > +int acpi_mpam_parse_resources(struct mpam_msc *msc, > + struct acpi_mpam_msc_node *tbl_msc) > +{ > + int i, err; > + char *ptr, *table_end; > + struct acpi_mpam_resource_node *resource; > + > + ptr = (char *)(tbl_msc + 1); > + table_end = ptr + tbl_msc->length; > + for (i = 0; i < tbl_msc->num_resource_nodes; i++) { > + u64 max_deps, remaining_table; > + > + if (ptr + sizeof(*resource) > table_end) > + return -EINVAL; > + > + resource = (struct acpi_mpam_resource_node *)ptr; > + > + remaining_table = table_end - ptr; > + max_deps = remaining_table / sizeof(struct acpi_mpam_func_deps); > + if (resource->num_functional_deps > max_deps) { > + pr_debug("MSC has impossible number of functional dependencies\n"); > + return -EINVAL; > + } > + > + err = acpi_mpam_parse_resource(msc, resource); > + if (err) > + return err; > + > + ptr += sizeof(*resource); > + ptr += resource->num_functional_deps * sizeof(struct acpi_mpam_func_deps); > + } > + > + return 0; > +} > + > +static bool __init parse_msc_pm_link(struct acpi_mpam_msc_node *tbl_msc, > + struct platform_device *pdev, > + u32 *acpi_id) > +{ > + char hid[sizeof(tbl_msc->hardware_id_linked_device) + 1]; > + bool acpi_id_valid = false; > + struct acpi_device *buddy; > + char uid[11]; > + int err; > + > + memset(&hid, 0, sizeof(hid)); > + memcpy(hid, &tbl_msc->hardware_id_linked_device, > + sizeof(tbl_msc->hardware_id_linked_device)); > + > + if (!strcmp(hid, ACPI_PROCESSOR_CONTAINER_HID)) { > + *acpi_id = tbl_msc->instance_id_linked_device; > + acpi_id_valid = true; > + } > + > + err = snprintf(uid, sizeof(uid), "%u", > + tbl_msc->instance_id_linked_device); > + if (err >= sizeof(uid)) { > + pr_debug("Failed to convert uid of device for power management."); > + return acpi_id_valid; > + } > + > + buddy = acpi_dev_get_first_match_dev(hid, uid, -1); > + if (buddy) > + device_link_add(&pdev->dev, &buddy->dev, DL_FLAG_STATELESS); > + > + return acpi_id_valid; > +} > + > +static int decode_interface_type(struct acpi_mpam_msc_node *tbl_msc, > + enum mpam_msc_iface *iface) > +{ > + switch (tbl_msc->interface_type) { > + case 0: > + *iface = MPAM_IFACE_MMIO; > + return 0; > + case 0xa: > + *iface = MPAM_IFACE_PCC; > + return 0; > + default: > + return -EINVAL; > + } > +} > + > +static int __init acpi_mpam_parse(void) > +{ > + struct acpi_table_header *table __free(acpi_table) = acpi_get_table_ret(ACPI_SIG_MPAM, 0); > + char *table_end, *table_offset = (char *)(table + 1); > + struct property_entry props[4]; /* needs a sentinel */ > + struct acpi_mpam_msc_node *tbl_msc; > + int next_res, next_prop, err = 0; > + struct acpi_device *companion; > + struct platform_device *pdev; > + enum mpam_msc_iface iface; > + struct resource res[3]; > + char uid[16]; > + u32 acpi_id; > + > + if (acpi_disabled || !system_supports_mpam() || IS_ERR(table)) > + return 0; > + > + if (table->revision < 1) > + return 0; > + > + table_end = (char *)table + table->length; > + > + while (table_offset < table_end) { > + tbl_msc = (struct acpi_mpam_msc_node *)table_offset; > + table_offset += tbl_msc->length; > + > + if (table_offset > table_end) { > + pr_debug("MSC entry overlaps end of ACPI table\n"); > + break; > + } > + > + /* > + * If any of the reserved fields are set, make no attempt to > + * parse the MSC structure. This MSC will still be counted, > + * meaning the MPAM driver can't probe against all MSC, and > + * will never be enabled. There is no way to enable it safely, > + * because we cannot determine safe system-wide partid and pmg > + * ranges in this situation. > + */ > + if (tbl_msc->reserved || tbl_msc->reserved1 || tbl_msc->reserved2) { > + pr_err_once("Unrecognised MSC, MPAM not usable\n"); > + pr_debug("MSC.%u: reserved field set\n", tbl_msc->identifier); > + continue; > + } > + > + if (!tbl_msc->mmio_size) { > + pr_debug("MSC.%u: marked as disabled\n", tbl_msc->identifier); > + continue; > + } > + > + if (decode_interface_type(tbl_msc, &iface)) { > + pr_debug("MSC.%u: unknown interface type\n", tbl_msc->identifier); > + continue; > + } > + > + next_res = 0; > + next_prop = 0; > + memset(res, 0, sizeof(res)); > + memset(props, 0, sizeof(props)); > + > + pdev = platform_device_alloc("mpam_msc", tbl_msc->identifier); > + if (!pdev) { > + err = -ENOMEM; > + break; > + } > + > + if (tbl_msc->length < sizeof(*tbl_msc)) { > + err = -EINVAL; > + break; > + } > + > + /* Some power management is described in the namespace: */ > + err = snprintf(uid, sizeof(uid), "%u", tbl_msc->identifier); > + if (err > 0 && err < sizeof(uid)) { > + companion = acpi_dev_get_first_match_dev("ARMHAA5C", uid, -1); > + if (companion) > + ACPI_COMPANION_SET(&pdev->dev, companion); > + else > + pr_debug("MSC.%u: missing namespace entry\n", tbl_msc->identifier); > + } > + > + if (iface == MPAM_IFACE_MMIO) { > + res[next_res++] = DEFINE_RES_MEM_NAMED(tbl_msc->base_address, > + tbl_msc->mmio_size, > + "MPAM:MSC"); > + } else if (iface == MPAM_IFACE_PCC) { > + props[next_prop++] = PROPERTY_ENTRY_U32("pcc-channel", > + tbl_msc->base_address); > + next_prop++; > + } > + > + acpi_mpam_parse_irqs(pdev, tbl_msc, res, &next_res); > + err = platform_device_add_resources(pdev, res, next_res); > + if (err) > + break; > + > + props[next_prop++] = PROPERTY_ENTRY_U32("arm,not-ready-us", > + tbl_msc->max_nrdy_usec); > + > + /* > + * The MSC's CPU affinity is described via its linked power > + * management device, but only if it points at a Processor or > + * Processor Container. > + */ > + if (parse_msc_pm_link(tbl_msc, pdev, &acpi_id)) { > + props[next_prop++] = PROPERTY_ENTRY_U32("cpu_affinity", > + acpi_id); > + } > + > + err = device_create_managed_software_node(&pdev->dev, props, > + NULL); > + if (err) > + break; > + > + /* Come back later if you want the RIS too */ > + err = platform_device_add_data(pdev, tbl_msc, tbl_msc->length); > + if (err) > + break; > + > + err = platform_device_add(pdev); > + if (err) > + break; > + } > + > + if (err) > + platform_device_put(pdev); > + > + return err; > +} > + > +int acpi_mpam_count_msc(void) > +{ > + struct acpi_table_header *table __free(acpi_table) = acpi_get_table_ret(ACPI_SIG_MPAM, 0); > + char *table_end, *table_offset = (char *)(table + 1); > + struct acpi_mpam_msc_node *tbl_msc; > + int count = 0; > + > + if (IS_ERR(table)) > + return 0; > + > + if (table->revision < 1) > + return 0; > + > + table_end = (char *)table + table->length; > + > + while (table_offset < table_end) { > + tbl_msc = (struct acpi_mpam_msc_node *)table_offset; > + if (!tbl_msc->mmio_size) > + continue; > + > + if (tbl_msc->length < sizeof(*tbl_msc)) > + return -EINVAL; > + if (tbl_msc->length > table_end - table_offset) > + return -EINVAL; > + table_offset += tbl_msc->length; > + > + count++; > + } > + > + return count; > +} > + acpi_mpam_count_msc() iterates the existing MSC node, which is part of acpi_mpam_parse(). So the question is why we can't drop acpi_mpam_count_msc() and maintain a variable to count the existing MSC nodes in acpi_mpam_parse() ? > +/* > + * Call after ACPI devices have been created, which happens behind acpi_scan_init() > + * called from subsys_initcall(). PCC requires the mailbox driver, which is > + * initialised from postcore_initcall(). > + */ > +subsys_initcall_sync(acpi_mpam_parse); > diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c > index fa9bb8c8ce95..835e3795ede3 100644 > --- a/drivers/acpi/tables.c > +++ b/drivers/acpi/tables.c > @@ -408,7 +408,7 @@ static const char table_sigs[][ACPI_NAMESEG_SIZE] __nonstring_array __initconst > ACPI_SIG_PSDT, ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT, > ACPI_SIG_IORT, ACPI_SIG_NFIT, ACPI_SIG_HMAT, ACPI_SIG_PPTT, > ACPI_SIG_NHLT, ACPI_SIG_AEST, ACPI_SIG_CEDT, ACPI_SIG_AGDI, > - ACPI_SIG_NBFT }; > + ACPI_SIG_NBFT, ACPI_SIG_MPAM }; > > #define ACPI_HEADER_SIZE sizeof(struct acpi_table_header) > > diff --git a/include/linux/acpi.h b/include/linux/acpi.h > index c5fd92cda487..af449964426b 100644 > --- a/include/linux/acpi.h > +++ b/include/linux/acpi.h > @@ -8,6 +8,7 @@ > #ifndef _LINUX_ACPI_H > #define _LINUX_ACPI_H > > +#include > #include > #include /* for struct resource */ > #include > @@ -221,6 +222,17 @@ void acpi_reserve_initial_tables (void); > void acpi_table_init_complete (void); > int acpi_table_init (void); > > +static inline struct acpi_table_header *acpi_get_table_ret(char *signature, u32 instance) > +{ > + struct acpi_table_header *table; > + int status = acpi_get_table(signature, instance, &table); > + > + if (ACPI_FAILURE(status)) > + return ERR_PTR(-ENOENT); > + return table; > +} > +DEFINE_FREE(acpi_table, struct acpi_table_header *, if (!IS_ERR(_T)) acpi_put_table(_T)) > + > int acpi_table_parse(char *id, acpi_tbl_table_handler handler); > int __init_or_acpilib acpi_table_parse_entries(char *id, > unsigned long table_size, int entry_id, > diff --git a/include/linux/arm_mpam.h b/include/linux/arm_mpam.h > new file mode 100644 > index 000000000000..3d6c39c667c3 > --- /dev/null > +++ b/include/linux/arm_mpam.h > @@ -0,0 +1,48 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* Copyright (C) 2025 Arm Ltd. */ > + > +#ifndef __LINUX_ARM_MPAM_H > +#define __LINUX_ARM_MPAM_H > + > +#include > +#include > + > +#define GLOBAL_AFFINITY ~0 > + > +struct mpam_msc; > + > +enum mpam_msc_iface { > + MPAM_IFACE_MMIO, /* a real MPAM MSC */ > + MPAM_IFACE_PCC, /* a fake MPAM MSC */ > +}; > + > +enum mpam_class_types { > + MPAM_CLASS_CACHE, /* Well known caches, e.g. L2 */ > + MPAM_CLASS_MEMORY, /* Main memory */ > + MPAM_CLASS_UNKNOWN, /* Everything else, e.g. SMMU */ > +}; > + > +#ifdef CONFIG_ACPI_MPAM > +/* Parse the ACPI description of resources entries for this MSC. */ > +int acpi_mpam_parse_resources(struct mpam_msc *msc, > + struct acpi_mpam_msc_node *tbl_msc); > + > +int acpi_mpam_count_msc(void); > +#else > +static inline int acpi_mpam_parse_resources(struct mpam_msc *msc, > + struct acpi_mpam_msc_node *tbl_msc) > +{ > + return -EINVAL; > +} > + > +static inline int acpi_mpam_count_msc(void) { return -EINVAL; } > +#endif > + > +static inline int mpam_ris_create(struct mpam_msc *msc, u8 ris_idx, > + enum mpam_class_types type, u8 class_id, > + int component_id) > +{ > + return -EINVAL; > +} > + > +#endif /* __LINUX_ARM_MPAM_H */ Thanks, Gavin