From patchwork Fri Nov 29 14:14:15 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Viresh Kumar X-Patchwork-Id: 21896 Return-Path: X-Original-To: linaro@patches.linaro.org Delivered-To: linaro@patches.linaro.org Received: from mail-oa0-f69.google.com (mail-oa0-f69.google.com [209.85.219.69]) by ip-10-151-82-157.ec2.internal (Postfix) with ESMTPS id D2A1423FC4 for ; Fri, 29 Nov 2013 14:14:32 +0000 (UTC) Received: by mail-oa0-f69.google.com with SMTP id h16sf32497191oag.8 for ; Fri, 29 Nov 2013 06:14:32 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:delivered-to:from:to:cc:subject :date:message-id:in-reply-to:references:in-reply-to:references :x-original-sender:x-original-authentication-results:precedence :mailing-list:list-id:list-post:list-help:list-archive :list-unsubscribe; bh=V0rj19AIFclsjgQAS7lXhtv/QXU/NF2IL+C74qP51/k=; b=OPPx4Zdp5ITKgU3ELL903BS27XTYT1S1wn9F8h+Y9L2KXB1aaYSAv5OfBAZDd9cvsl sTKvkSm2zvSDpj8rHa3FPXAkI+atKwJZAAyKu8OjuXTBFxCqCnOFSTaPALcnT29up5G6 VZhrj0clcnFU3CKJtzXLwfFfVOktvCqKfJNqhoLGIRN9KRl9kjRDLqQCwso9aTr0z+67 Bo5QHYCvaiUWBfieM3t3hEBE2n3HIxZBPzpcSrs+g0ICNvKgY2KHAaurIjqHgdIGXeRD YsZ13Hi2q9FX5f/7ctS9DEL7ypTtoHssm9n1eHlaDvIHNEP4LRBDKd6MYpn9GpOERu+Z XDdw== X-Gm-Message-State: ALoCoQm87XnqfHM/hu2DnzYNdCwFwYjxh38XRhWY5gUyvmXjuVVz+9Tj7K2q9wnlmZ8z395ZUs9V X-Received: by 10.42.100.13 with SMTP id y13mr674942icn.32.1385734472170; Fri, 29 Nov 2013 06:14:32 -0800 (PST) MIME-Version: 1.0 X-BeenThere: patchwork-forward@linaro.org Received: by 10.49.24.174 with SMTP id v14ls2200125qef.74.gmail; Fri, 29 Nov 2013 06:14:32 -0800 (PST) X-Received: by 10.58.237.99 with SMTP id vb3mr12386vec.86.1385734471979; Fri, 29 Nov 2013 06:14:31 -0800 (PST) Received: from mail-vc0-f173.google.com (mail-vc0-f173.google.com [209.85.220.173]) by mx.google.com with ESMTPS id ov5si24911183vcb.97.2013.11.29.06.14.31 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 29 Nov 2013 06:14:31 -0800 (PST) Received-SPF: neutral (google.com: 209.85.220.173 is neither permitted nor denied by best guess record for domain of patch+caf_=patchwork-forward=linaro.org@linaro.org) client-ip=209.85.220.173; Received: by mail-vc0-f173.google.com with SMTP id ia6so6560016vcb.4 for ; Fri, 29 Nov 2013 06:14:31 -0800 (PST) X-Received: by 10.52.227.233 with SMTP id sd9mr763005vdc.53.1385734471878; Fri, 29 Nov 2013 06:14:31 -0800 (PST) X-Forwarded-To: patchwork-forward@linaro.org X-Forwarded-For: patch@linaro.org patchwork-forward@linaro.org Delivered-To: patches@linaro.org Received: by 10.220.174.196 with SMTP id u4csp95364vcz; Fri, 29 Nov 2013 06:14:31 -0800 (PST) X-Received: by 10.67.21.130 with SMTP id hk2mr53367799pad.76.1385734470396; Fri, 29 Nov 2013 06:14:30 -0800 (PST) Received: from mail-pb0-f52.google.com (mail-pb0-f52.google.com [209.85.160.52]) by mx.google.com with ESMTPS id hb3si39943053pac.210.2013.11.29.06.14.30 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 29 Nov 2013 06:14:30 -0800 (PST) Received-SPF: neutral (google.com: 209.85.160.52 is neither permitted nor denied by best guess record for domain of viresh.kumar@linaro.org) client-ip=209.85.160.52; Received: by mail-pb0-f52.google.com with SMTP id uo5so14450436pbc.25 for ; Fri, 29 Nov 2013 06:14:30 -0800 (PST) X-Received: by 10.66.14.41 with SMTP id m9mr33018856pac.123.1385734469807; Fri, 29 Nov 2013 06:14:29 -0800 (PST) Received: from localhost ([122.167.133.207]) by mx.google.com with ESMTPSA id p1sm102479172pbo.12.2013.11.29.06.14.25 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Fri, 29 Nov 2013 06:14:29 -0800 (PST) From: Viresh Kumar To: rjw@rjwysocki.net Cc: linaro-kernel@lists.linaro.org, patches@linaro.org, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, nm@ti.com, ceh@ti.com, Viresh Kumar Subject: [PATCH V4 2/2] cpufreq: Make sure CPU is running on a freq from freq-table Date: Fri, 29 Nov 2013 19:44:15 +0530 Message-Id: X-Mailer: git-send-email 1.7.12.rc2.18.g61b472e In-Reply-To: <0875dc1b263f39081232c560fc72c15cd42dfc6f.1385734305.git.viresh.kumar@linaro.org> References: <0875dc1b263f39081232c560fc72c15cd42dfc6f.1385734305.git.viresh.kumar@linaro.org> In-Reply-To: <0875dc1b263f39081232c560fc72c15cd42dfc6f.1385734305.git.viresh.kumar@linaro.org> References: <0875dc1b263f39081232c560fc72c15cd42dfc6f.1385734305.git.viresh.kumar@linaro.org> X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: viresh.kumar@linaro.org X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 209.85.220.173 is neither permitted nor denied by best guess record for domain of patch+caf_=patchwork-forward=linaro.org@linaro.org) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Precedence: list Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org List-ID: X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , Sometimes boot loaders set CPU frequency to a value outside of frequency table present with cpufreq core. In such cases CPU might be unstable if it has to run on that frequency for long duration of time and so its better to set it to a frequency which is specified in freq-table. This also makes cpufreq stats inconsistent as cpufreq-stats would fail to register because current frequency of CPU isn't found in freq-table. Because we don't want this change to effect boot process badly, we go for the next freq which is >= policy->cur ('cur' must be set by now, otherwise we will end up setting freq to lowest of the table as 'cur' is initialized to zero). In case current frequency doesn't match any frequency from freq-table, we throw warnings to user, so that user can get this fixed in their bootloaders or freq-tables. Reported-by: Carlos Hernandez Reported-and-tested-by: Nishanth Menon Signed-off-by: Viresh Kumar --- drivers/cpufreq/cpufreq.c | 40 ++++++++++++++++++++++++++++++++++++++++ drivers/cpufreq/freq_table.c | 22 ++++++++++++++++++++++ include/linux/cpufreq.h | 2 ++ 3 files changed, 64 insertions(+) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 606224a..f13320a 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1042,6 +1042,46 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, } } + /* + * Sometimes boot loaders set CPU frequency to a value outside of + * frequency table present with cpufreq core. In such cases CPU might be + * unstable if it has to run on that frequency for long duration of time + * and so its better to set it to a frequency which is specified in + * freq-table. This also makes cpufreq stats inconsistent as + * cpufreq-stats would fail to register because current frequency of CPU + * isn't found in freq-table. + * + * Because we don't want this change to effect boot process badly, we go + * for the next freq which is >= policy->cur ('cur' must be set by now, + * otherwise we will end up setting freq to lowest of the table as 'cur' + * is initialized to zero). + * + * We are passing target-freq as "policy->cur - 1" otherwise + * __cpufreq_driver_target() would simply fail, as policy->cur will be + * equal to target-freq. + */ + if (!(cpufreq_driver->flags & CPUFREQ_SKIP_INITIAL_FREQ_CHECK) + && has_target()) { + /* Are we running at unknown frequency ? */ + ret = cpufreq_frequency_table_get_index(policy, policy->cur); + if (ret == -EINVAL) { + /* Warn user and fix it */ + pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n", + __func__, policy->cpu, policy->cur); + ret = __cpufreq_driver_target(policy, policy->cur - 1, + CPUFREQ_RELATION_L); + + /* + * Reaching here after boot in a few seconds may not + * mean that system will remain stable at "unknown" + * frequency for longer duration. Hence, a BUG_ON(). + */ + BUG_ON(ret); + pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n", + __func__, policy->cpu, policy->cur); + } + } + /* related cpus should atleast have policy->cpus */ cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus); diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c index 3458d27..a8ac042 100644 --- a/drivers/cpufreq/freq_table.c +++ b/drivers/cpufreq/freq_table.c @@ -178,7 +178,29 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy, } EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target); +int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy, + unsigned int freq) +{ + struct cpufreq_frequency_table *table; + int i; + + table = cpufreq_frequency_get_table(policy->cpu); + if (unlikely(!table)) { + pr_debug("%s: Unable to find frequency table\n", __func__); + return -ENOENT; + } + + for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { + if (table[i].frequency == freq) + return i; + } + + return -EINVAL; +} +EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_index); + static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table); + /** * show_available_freqs - show available frequencies for the specified CPU */ diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 13b8802..03174ab 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -456,6 +456,8 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation, unsigned int *index); +int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy, + unsigned int freq); void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy); ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf);