From patchwork Thu Sep 19 08:45:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jie Zhan X-Patchwork-Id: 13807519 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 2E096CE8D5F for ; Thu, 19 Sep 2024 08:53:23 +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-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=aDDNZlZMaBmVNYg9SmPmXJ19rXzcDuOkee5OxKMWLuY=; b=fcis2Bj5hstR0qZP2KXtq992/d 3Pu2jdRsmR5VkywmQc7jBffkHTGz3zLhZpf5QxXvWIpYoh+MIihplGH03k4aO63+9rfDniMBt7T1D cN+vlGLHoFQC/xRH7v+WoC7d4Ho9+MrKRujJp0FOucvCO3e8Y8WUgWly9Lyon17VIBx8UEjRpZd9z 3cIJWA3pfOsfdkJIFzKqvVAs1gB13opcTGWHbQxKwSYL7v4Id2jo+jhX3e75jXgENPNlLcSgQIE6m FG419slqaUbielREwoK/PT/EWtoFb9Q+hwJq0+ykh7Vkop9XA/fC3lDv24sN05v3A076J8wfjbPY5 vmK6Y36A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1srCuU-00000009poi-3ryU; Thu, 19 Sep 2024 08:53:10 +0000 Received: from szxga06-in.huawei.com ([45.249.212.32]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1srCtM-00000009piC-1NIz for linux-arm-kernel@lists.infradead.org; Thu, 19 Sep 2024 08:52:03 +0000 Received: from mail.maildlp.com (unknown [172.19.163.44]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4X8Tln4Xkdz1ym6V; Thu, 19 Sep 2024 16:51:49 +0800 (CST) Received: from dggpeml500019.china.huawei.com (unknown [7.185.36.137]) by mail.maildlp.com (Postfix) with ESMTPS id 407FA140202; Thu, 19 Sep 2024 16:51:49 +0800 (CST) Received: from localhost.localdomain (10.90.30.45) by dggpeml500019.china.huawei.com (7.185.36.137) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Thu, 19 Sep 2024 16:51:48 +0800 From: Jie Zhan To: , , , , CC: , , , , , , , , , , , Subject: [PATCH v3 1/2] cppc_cpufreq: Use desired perf if feedback ctrs are 0 or unchanged Date: Thu, 19 Sep 2024 16:45:51 +0800 Message-ID: <20240919084552.3591400-2-zhanjie9@hisilicon.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20240919084552.3591400-1-zhanjie9@hisilicon.com> References: <20240919084552.3591400-1-zhanjie9@hisilicon.com> MIME-Version: 1.0 X-Originating-IP: [10.90.30.45] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpeml500019.china.huawei.com (7.185.36.137) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240919_015200_987066_2F2A33AA X-CRM114-Status: GOOD ( 16.82 ) 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 The CPPC performance feedback counters could be 0 or unchanged when the target cpu is in a low-power idle state, e.g. power-gated or clock-gated. When the counters are 0, cppc_cpufreq_get_rate() returns 0 KHz, which makes cpufreq_online() get a false error and fail to generate a cpufreq policy. When the counters are unchanged, the existing cppc_perf_from_fbctrs() returns a cached desired perf, but some platforms may update the real frequency back to the desired perf reg. For the above cases in cppc_cpufreq_get_rate(), get the latest desired perf to reflect the frequency; if failed, return the cached desired perf. Fixes: 6a4fec4f6d30 ("cpufreq: cppc: cppc_cpufreq_get_rate() returns zero in all error cases.") Signed-off-by: Jie Zhan Reviewed-by: Zeng Heng Reviewed-by: Ionela Voinescu Reviewed-by: Huisong Li --- drivers/cpufreq/cppc_cpufreq.c | 49 +++++++++++++++++++++++++++------- 1 file changed, 39 insertions(+), 10 deletions(-) diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index bafa32dd375d..e55192303a9f 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -118,6 +118,9 @@ static void cppc_scale_freq_workfn(struct kthread_work *work) perf = cppc_perf_from_fbctrs(cpu_data, &cppc_fi->prev_perf_fb_ctrs, &fb_ctrs); + if (!perf) + return; + cppc_fi->prev_perf_fb_ctrs = fb_ctrs; perf <<= SCHED_CAPACITY_SHIFT; @@ -726,11 +729,26 @@ static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data, /* Check to avoid divide-by zero and invalid delivered_perf */ if (!delta_reference || !delta_delivered) - return cpu_data->perf_ctrls.desired_perf; + return 0; return (reference_perf * delta_delivered) / delta_reference; } +static int cppc_get_perf_ctrs_sample(int cpu, + struct cppc_perf_fb_ctrs *fb_ctrs_t0, + struct cppc_perf_fb_ctrs *fb_ctrs_t1) +{ + int ret; + + ret = cppc_get_perf_ctrs(cpu, fb_ctrs_t0); + if (ret) + return ret; + + udelay(2); /* 2usec delay between sampling */ + + return cppc_get_perf_ctrs(cpu, fb_ctrs_t1); +} + static unsigned int cppc_cpufreq_get_rate(unsigned int cpu) { struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0}; @@ -746,18 +764,29 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu) cpufreq_cpu_put(policy); - ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t0); - if (ret) - return 0; - - udelay(2); /* 2usec delay between sampling */ - - ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t1); - if (ret) - return 0; + ret = cppc_get_perf_ctrs_sample(cpu, &fb_ctrs_t0, &fb_ctrs_t1); + if (ret) { + if (ret == -EFAULT) + goto out_invalid_counters; + else + return 0; + } delivered_perf = cppc_perf_from_fbctrs(cpu_data, &fb_ctrs_t0, &fb_ctrs_t1); + if (!delivered_perf) + goto out_invalid_counters; + + return cppc_perf_to_khz(&cpu_data->perf_caps, delivered_perf); + +out_invalid_counters: + /* + * Feedback counters could be unchanged or 0 when a cpu enters a + * low-power idle state, e.g. clock-gated or power-gated. + * Get the lastest or cached desired perf for reflecting frequency. + */ + if (cppc_get_desired_perf(cpu, &delivered_perf)) + delivered_perf = cpu_data->perf_ctrls.desired_perf; return cppc_perf_to_khz(&cpu_data->perf_caps, delivered_perf); }