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=-13.1 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 B1668C43461 for ; Mon, 7 Sep 2020 17:52:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7EBC5208C7 for ; Mon, 7 Sep 2020 17:52:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729617AbgIGRwk (ORCPT ); Mon, 7 Sep 2020 13:52:40 -0400 Received: from foss.arm.com ([217.140.110.172]:33980 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729056AbgIGL5z (ORCPT ); Mon, 7 Sep 2020 07:57:55 -0400 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 4472E1045; Mon, 7 Sep 2020 04:57:52 -0700 (PDT) Received: from [10.57.6.175] (unknown [10.57.6.175]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D51103F66E; Mon, 7 Sep 2020 04:57:50 -0700 (PDT) Subject: Re: [PATCH v3] perf: arm_dsu: Support DSU ACPI devices To: will@kernel.org, tuanphan@os.amperecomputing.com Cc: patches@amperecomputing.com, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <1597451980-11405-1-git-send-email-tuanphan@os.amperecomputing.com> <20200907110236.GA12174@willie-the-truck> From: Suzuki K Poulose Message-ID: Date: Mon, 7 Sep 2020 13:02:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20200907110236.GA12174@willie-the-truck> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/07/2020 12:02 PM, Will Deacon wrote: > [+ Suzuki as I'd like his Ack on this] > Thanks Will ! > On Fri, Aug 14, 2020 at 05:39:40PM -0700, Tuan Phan wrote: >> Add support for probing device from ACPI node. >> Each DSU ACPI node and its associated cpus are inside a cluster node. >> >> Signed-off-by: Tuan Phan >> --- >> Changes in v3: >> - Based on the latest ARM ACPI binding at: https://developer.arm.com/documentation/den0093/c/ >> >> Changes in v2: >> - Removed IRQF_SHARED. >> - Fixed ACPI runtime detection. >> >> drivers/perf/arm_dsu_pmu.c | 68 ++++++++++++++++++++++++++++++++++++++++------ >> 1 file changed, 60 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/perf/arm_dsu_pmu.c b/drivers/perf/arm_dsu_pmu.c >> index 96ed93c..4be355d 100644 >> --- a/drivers/perf/arm_dsu_pmu.c >> +++ b/drivers/perf/arm_dsu_pmu.c >> @@ -11,6 +11,7 @@ >> #define DRVNAME PMUNAME "_pmu" >> #define pr_fmt(fmt) DRVNAME ": " fmt >> >> +#include >> #include >> #include >> #include >> @@ -603,18 +604,21 @@ static struct dsu_pmu *dsu_pmu_alloc(struct platform_device *pdev) >> } >> >> /** >> - * dsu_pmu_dt_get_cpus: Get the list of CPUs in the cluster. >> + * dsu_pmu_dt_get_cpus: Get the list of CPUs in the cluster >> + * from device tree. >> */ >> -static int dsu_pmu_dt_get_cpus(struct device_node *dev, cpumask_t *mask) >> +static int dsu_pmu_dt_get_cpus(struct platform_device *pdev) >> { >> int i = 0, n, cpu; >> struct device_node *cpu_node; >> + struct dsu_pmu *dsu_pmu = >> + (struct dsu_pmu *) platform_get_drvdata(pdev); >> >> - n = of_count_phandle_with_args(dev, "cpus", NULL); >> + n = of_count_phandle_with_args(pdev->dev.of_node, "cpus", NULL); >> if (n <= 0) >> return -ENODEV; >> for (; i < n; i++) { >> - cpu_node = of_parse_phandle(dev, "cpus", i); >> + cpu_node = of_parse_phandle(pdev->dev.of_node, "cpus", i); >> if (!cpu_node) >> break; >> cpu = of_cpu_node_to_id(cpu_node); >> @@ -626,11 +630,51 @@ static int dsu_pmu_dt_get_cpus(struct device_node *dev, cpumask_t *mask) >> */ >> if (cpu < 0) >> continue; >> - cpumask_set_cpu(cpu, mask); >> + cpumask_set_cpu(cpu, &dsu_pmu->associated_cpus); >> } >> return 0; >> } >> >> +/** >> + * dsu_pmu_acpi_get_cpus: Get the list of CPUs in the cluster >> + * from ACPI. >> + */ >> +static int dsu_pmu_acpi_get_cpus(struct platform_device *pdev) >> +{ >> + int cpu; >> + struct dsu_pmu *dsu_pmu = (struct dsu_pmu *) platform_get_drvdata(pdev); >> + >> + /* >> + * A dsu pmu node is inside a cluster parent node along with cpu nodes. >> + * We need to find out all cpus that have the same parent with this pmu. >> + */ >> + for_each_possible_cpu(cpu) { >> + struct acpi_device *acpi_dev = ACPI_COMPANION(get_cpu_device(cpu)); minor nit: Please could we split this into : struct acpi_device *acpi_dev; struct device *cpu_dev = get_cpu_device(cpu); if (!cpu_dev) continue; acpi_dev = ACPI_COMPANION(cpu_dev); ... So that we are explicitly clear that we don't end up in NULL pointer dereferences (ACPI_COMPANION() is safe btw). Otherwise, with Will's comments addressed, looks fine to me. Appreciate a Cc in the next posting. Suzuki