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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3DF75C43334 for ; Tue, 7 Jun 2022 22:19:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357975AbiFGWTa (ORCPT ); Tue, 7 Jun 2022 18:19:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378852AbiFGVNr (ORCPT ); Tue, 7 Jun 2022 17:13:47 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D21F152D8F; Tue, 7 Jun 2022 11:54:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5D74F61277; Tue, 7 Jun 2022 18:54:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6AE98C385A5; Tue, 7 Jun 2022 18:54:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654628063; bh=DEoc8i7aPgstshbzPGcR3ZykmcCRzy2UNNk8exG0MWY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eZL5A55d34p77nl+lT9otwQREfWZ52xiqtlOgb90mPS3vfjL4VqrOekl73jRxuxoQ 9ZR6MnKdkQ7TLhvAUF4NG9PSewEkTiJus0gfY2jv19qFzl9MMLkEDMuyoge5CA+gUF xEjvzDTrURSCi5bYKgSjBqAnfny2ZJVeyOJC51Y0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pierre Gondois , Sudeep Holla , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 5.18 191/879] ACPI: CPPC: Assume no transition latency if no PCCT Date: Tue, 7 Jun 2022 18:55:09 +0200 Message-Id: <20220607165008.385335751@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607165002.659942637@linuxfoundation.org> References: <20220607165002.659942637@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Pierre Gondois [ Upstream commit 6380b7b2b29da9d9c5ab2d4a265901cd93ba3696 ] The transition_delay_us (struct cpufreq_policy) is currently defined as: Preferred average time interval between consecutive invocations of the driver to set the frequency for this policy. To be set by the scaling driver (0, which is the default, means no preference). The transition_latency represents the amount of time necessary for a CPU to change its frequency. A PCCT table advertises mutliple values: - pcc_nominal: Expected latency to process a command, in microseconds - pcc_mpar: The maximum number of periodic requests that the subspace channel can support, reported in commands per minute. 0 indicates no limitation. - pcc_mrtt: The minimum amount of time that OSPM must wait after the completion of a command before issuing the next command, in microseconds. cppc_get_transition_latency() allows to get the max of them. commit d4f3388afd48 ("cpufreq / CPPC: Set platform specific transition_delay_us") allows to select transition_delay_us based on the platform, and fallbacks to cppc_get_transition_latency() otherwise. If _CPC objects are not using PCC channels (no PPCT table), the transition_delay_us is set to CPUFREQ_ETERNAL, leading to really long periods between frequency updates (~4s). If the desired_reg, where performance requests are written, is in SystemMemory or SystemIo ACPI address space, there is no delay in requests. So return 0 instead of CPUFREQ_ETERNAL, leading to transition_delay_us being set to LATENCY_MULTIPLIER us (1000 us). This patch also adds two macros to check the address spaces. Signed-off-by: Pierre Gondois Reviewed-by: Sudeep Holla Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/acpi/cppc_acpi.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index bc1454789a06..34576ab0e2e1 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -100,6 +100,16 @@ static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr); (cpc)->cpc_entry.reg.space_id == \ ACPI_ADR_SPACE_PLATFORM_COMM) +/* Check if a CPC register is in SystemMemory */ +#define CPC_IN_SYSTEM_MEMORY(cpc) ((cpc)->type == ACPI_TYPE_BUFFER && \ + (cpc)->cpc_entry.reg.space_id == \ + ACPI_ADR_SPACE_SYSTEM_MEMORY) + +/* Check if a CPC register is in SystemIo */ +#define CPC_IN_SYSTEM_IO(cpc) ((cpc)->type == ACPI_TYPE_BUFFER && \ + (cpc)->cpc_entry.reg.space_id == \ + ACPI_ADR_SPACE_SYSTEM_IO) + /* Evaluates to True if reg is a NULL register descriptor */ #define IS_NULL_REG(reg) ((reg)->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY && \ (reg)->address == 0 && \ @@ -1447,6 +1457,9 @@ EXPORT_SYMBOL_GPL(cppc_set_perf); * transition latency for performance change requests. The closest we have * is the timing information from the PCCT tables which provides the info * on the number and frequency of PCC commands the platform can handle. + * + * If desired_reg is in the SystemMemory or SystemIo ACPI address space, + * then assume there is no latency. */ unsigned int cppc_get_transition_latency(int cpu_num) { @@ -1472,7 +1485,9 @@ unsigned int cppc_get_transition_latency(int cpu_num) return CPUFREQ_ETERNAL; desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF]; - if (!CPC_IN_PCC(desired_reg)) + if (CPC_IN_SYSTEM_MEMORY(desired_reg) || CPC_IN_SYSTEM_IO(desired_reg)) + return 0; + else if (!CPC_IN_PCC(desired_reg)) return CPUFREQ_ETERNAL; if (pcc_ss_id < 0) -- 2.35.1