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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 C1C30C433DF for ; Mon, 10 Aug 2020 10:20:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6ABD2070B for ; Mon, 10 Aug 2020 10:20:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726141AbgHJKUA (ORCPT ); Mon, 10 Aug 2020 06:20:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:34206 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725846AbgHJKUA (ORCPT ); Mon, 10 Aug 2020 06:20:00 -0400 Received: from gaia (unknown [95.146.230.158]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 65823206C3; Mon, 10 Aug 2020 10:19:57 +0000 (UTC) Date: Mon, 10 Aug 2020 11:19:55 +0100 From: Catalin Marinas To: Sudeep Holla Cc: Sumit Gupta , Kefeng Wang , Will Deacon , Mikko Perttunen , Viresh Kumar , Hulk Robot , "linux-kernel@vger.kernel.org List" , linux-arm-kernel@lists.infradead.org, Bibek Basu , linux-tegra , Thierry Reding , Jon Hunter Subject: Re: [PATCH -next] arm64: Export __cpu_logical_map Message-ID: <20200810101954.GA9480@gaia> References: <20200724030433.22287-1-wangkefeng.wang@huawei.com> <82f750c4-d423-1ed8-a158-e75153745e07@huawei.com> <20200724131059.GB6521@bogus> <00cf6e67-16ed-872d-2c16-0ceea6b6f514@nvidia.com> <20200727160515.GA8003@bogus> <20200810074956.GB28091@bogus> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200810074956.GB28091@bogus> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-tegra-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org On Mon, Aug 10, 2020 at 08:49:56AM +0100, Sudeep Holla wrote: > On Sat, Aug 01, 2020 at 05:46:43PM +0530, Sumit Gupta wrote: > > > > > > > ERROR: modpost: "__cpu_logical_map" [drivers/cpufreq/tegra194-cpufreq.ko] undefined! > > > > > > > > > > > > > > ARM64 tegra194-cpufreq driver use cpu_logical_map, export > > > > > > > __cpu_logical_map to fix build issue. > > > > > > > > > > > > > > > > > I wonder why like other instances in the drivers, the mpidr is not get > > > > > directly from the cpu. The cpufreq_driver->init call happens when the cpu > > > > > is being brought online and is executed on the required cpu IIUC. > > > > > > > > Yes, this occurs during hotplug case. > > > > But in the case of system boot, 'cpufreq_driver->init' is called later > > > > during cpufreq platform driver's probe. The value of CPU in 'policy->cpu' > > > > can be different from the current CPU. That's why read_cpuid_mpidr() can't > > > > be used. > > > > > > Fair enough, why not do cross call like in set_target ? Since it is one-off > > > in init, I don't see any issue when you are doing it runtime for set_target. > > > > > > > > read_cpuid_mpidr() is inline and avoids having to export the logical_cpu_map. > > > > > Though we may not add physical hotplug anytime soon, less dependency > > > > > on this cpu_logical_map is better given that we can resolve this without > > > > > the need to access the map. > > > > > > To be honest, we have tried to remove all the dependency on cluster id > > > in generic code as it is not well defined. This one is tegra specific > > > driver so should be fine. But I am still bit nervous to export > > > cpu_logical_map as we have no clue what that would mean for physical > > > hotplug. > > > > As suggested, I have done below change to get the cluster number using > > read_cpuid_mpidr(). Please review and suggest if this looks ok? > > I will send formal patch if the change is fine. > > > > diff --git a/drivers/cpufreq/tegra194-cpufreq.c > > b/drivers/cpufreq/tegra194-cpufreq.c > > index bae527e..06f5ccf 100644 > > --- a/drivers/cpufreq/tegra194-cpufreq.c > > +++ b/drivers/cpufreq/tegra194-cpufreq.c > > @@ -56,9 +56,11 @@ struct read_counters_work { > > > > static struct workqueue_struct *read_counters_wq; > > > > -static enum cluster get_cpu_cluster(u8 cpu) > > +static void get_cpu_cluster(void *cluster) > > { > > - return MPIDR_AFFINITY_LEVEL(cpu_logical_map(cpu), 1); > > + u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; > > + > > + *((uint32_t *) cluster) = MPIDR_AFFINITY_LEVEL(mpidr, 1); > > } > > > > /* > > @@ -186,8 +188,10 @@ static unsigned int tegra194_get_speed(u32 cpu) > > static int tegra194_cpufreq_init(struct cpufreq_policy *policy) > > { > > struct tegra194_cpufreq_data *data = cpufreq_get_driver_data(); > > - int cl = get_cpu_cluster(policy->cpu); > > u32 cpu; > > + u32 cl; > > + > > + smp_call_function_single(policy->cpu, get_cpu_cluster, &cl, true); > > Thanks for this, looks good to me. You can add: > > Reviewed-by: Sudeep Holla I already merged Kefeng's __cpu_logical_map fix (commit eaecca9e7710) but if the above goes in, I can drop the EXPORT_SYMBOL part (and keep the rest as it's a good refactoring). -- Catalin