linux-kernel - [Patch] cpufreq: replace cpu_logical_map with read_cpuid

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Message-ID: <1597174997-22505-1-git-send-email-sumitg@nvidia.com>
Date:   Wed, 12 Aug 2020 01:13:17 +0530
From:   Sumit Gupta <sumitg@...dia.com>
To:     <sudeep.holla@....com>, <rjw@...ysocki.net>,
        <viresh.kumar@...aro.org>, <catalin.marinas@....com>,
        <thierry.reding@...il.com>, <jonathanh@...dia.com>,
        <linux-pm@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
CC:     <bbasu@...dia.com>, <sumitg@...dia.com>,
        <wangkefeng.wang@...wei.com>
Subject: [Patch] cpufreq: replace cpu_logical_map with read_cpuid_mpir

Commit eaecca9e7710 ("arm64: Fix __cpu_logical_map undefined issue")
fixes the issue with building tegra194 cpufreq driver as module. But
the fix might cause problem while supporting physical cpu hotplug[1].

This patch fixes the original problem by avoiding use of cpu_logical_map().
Instead calling read_cpuid_mpidr() to get MPIDR on target cpu.

[1] https://lore.kernel.org/linux-arm-kernel/20200724131059.GB6521@bogus/

Reviewed-by: Sudeep Holla <sudeep.holla@....com>
Signed-off-by: Sumit Gupta <sumitg@...dia.com>
---
 drivers/cpufreq/tegra194-cpufreq.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/cpufreq/tegra194-cpufreq.c b/drivers/cpufreq/tegra194-cpufreq.c
index bae527e..e1d931c 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);
 
 	if (cl >= data->num_clusters)
 		return -EINVAL;
-- 
2.7.4