From patchwork Wed Aug 26 13:03:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ionela Voinescu X-Patchwork-Id: 11738349 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 04D201751 for ; Wed, 26 Aug 2020 13:06:19 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CD5C420707 for ; Wed, 26 Aug 2020 13:06:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="0IYszONF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD5C420707 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:MIME-Version:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:References:In-Reply-To:Message-Id:Date:Subject:To: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=sNhImuxydlpIE3+2rddpNpB4MkdDZmMJjl8pzeRNL9k=; b=0IYszONF5/6cyG4E5LouPTIVwR dl5Q6g37KGCMTp7b1rjRLtVg/wqsT3lrasO1d+sTV4zr4pbYKl2gBj8lYJ1yDtfIqujP7HvcSvhT6 GlO+bJR2pz9XppG3B+2hlMVHwhV1830NLC/jsy2A72eLEk2i+LRtsvSHBdbmSExUGSFiMVwtWAWeZ rLCRokVHnzGMtJX6VjFK1Yf5HdKfzcRpn51cQbyIZLb4fKpARq+mkNiz/G9dqPfEsjhJb5Wnp7AMQ 9u0Jzw/sIDKamU2n0y3Bdq3pK5pNeMP51MtdKkNpJIDrM2PHW6A1EaG5J6QQ1URUMHb0VzFY+U8kE WEEz8S3g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kAv6R-0001hw-AH; Wed, 26 Aug 2020 13:04:35 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kAv60-0001XY-Vd for linux-arm-kernel@lists.infradead.org; Wed, 26 Aug 2020 13:04:10 +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 880C81045; Wed, 26 Aug 2020 06:04:07 -0700 (PDT) Received: from e108754-lin.cambridge.arm.com (unknown [10.1.199.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 185193F68F; Wed, 26 Aug 2020 06:04:05 -0700 (PDT) From: Ionela Voinescu To: catalin.marinas@arm.com, will@kernel.org, sudeep.holla@arm.com Subject: [PATCH 4/4] arm64: implement CPPC FFH support using AMUs Date: Wed, 26 Aug 2020 14:03:09 +0100 Message-Id: <20200826130309.28027-5-ionela.voinescu@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200826130309.28027-1-ionela.voinescu@arm.com> References: <20200826130309.28027-1-ionela.voinescu@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200826_090409_148282_4666FD53 X-CRM114-Status: GOOD ( 16.84 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: souvik.chakravarty@arm.com, viresh.kumar@linaro.org, valentin.schneider@arm.com, linux-kernel@vger.kernel.org, dietmar.eggemann@arm.com, ionela.voinescu@arm.com, morten.rasmussen@arm.com, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org If Activity Monitors (AMUs) are present, two of the counters can be used to implement support for CPPC's (Collaborative Processor Performance Control) delivered and reference performance monitoring functionality using FFH (Functional Fixed Hardware). Given that counters for a certain CPU can only be read from that CPU, while FFH operations can be called from any CPU for any of the CPUs, use smp_call_function_single() to provide the requested values. Therefore, depending on the register addresses, the following values are returned: - 0x0 (DeliveredPerformanceCounterRegister): AMU core counter - 0x1 (ReferencePerformanceCounterRegister): AMU constant counter The use of Activity Monitors is hidden behind the generic {read,store}_{corecnt,constcnt}() functions. Read functionality for these two registers represents the only current FFH support for CPPC. Read operations for other register values or write operation for all registers are unsupported. Therefore, keep CPPC's FFH unsupported if no CPUs have valid AMU frequency counters. Signed-off-by: Ionela Voinescu Cc: Catalin Marinas Cc: Will Deacon --- arch/arm64/kernel/topology.c | 62 ++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index edc44b46e34f..cb0372de9aa9 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -326,3 +326,65 @@ void topology_scale_freq_tick(void) this_cpu_write(arch_core_cycles_prev, core_cnt); this_cpu_write(arch_const_cycles_prev, const_cnt); } + +#ifdef CONFIG_ACPI_CPPC_LIB +#include + +static inline +int counters_read_on_cpu(int cpu, smp_call_func_t func, u64 *val) +{ + const struct cpumask *cnt_cpu_mask = cpus_with_amu_counters(); + + if (!cnt_cpu_mask || !cpumask_test_cpu(cpu, cnt_cpu_mask)) + return -EOPNOTSUPP; + + smp_call_function_single(cpu, func, val, 1); + + return 0; +} + +/* + * Refer to drivers/acpi/cppc_acpi.c for the description of the functions + * below. + */ +bool cpc_ffh_supported(void) +{ + const struct cpumask *cnt_cpu_mask = cpus_with_amu_counters(); + int cpu = nr_cpu_ids; + + if (cnt_cpu_mask) + cpu = cpumask_any_and(cnt_cpu_mask, cpu_present_mask); + + if ((cpu >= nr_cpu_ids) || !freq_counters_valid(cpu)) + return false; + + return true; +} + +int cpc_read_ffh(int cpu, struct cpc_reg *reg, u64 *val) +{ + int ret = -EOPNOTSUPP; + + switch ((u64)reg->address) { + case 0x0: + ret = counters_read_on_cpu(cpu, store_corecnt, val); + break; + case 0x1: + ret = counters_read_on_cpu(cpu, store_constcnt, val); + break; + } + + if (!ret) { + *val &= GENMASK_ULL(reg->bit_offset + reg->bit_width - 1, + reg->bit_offset); + *val >>= reg->bit_offset; + } + + return ret; +} + +int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val) +{ + return -EOPNOTSUPP; +} +#endif /* CONFIG_ACPI_CPPC_LIB */