linux-kernel - [PATCH 1/2] cpufreq: tegra186: Fix initial frequency

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Date:   Sun, 12 Jul 2020 11:06:44 +0100
From:   Jon Hunter <jonathanh@...dia.com>
To:     Thierry Reding <thierry.reding@...il.com>
CC:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Jon Hunter <jonathanh@...dia.com>
Subject: [PATCH 1/2] cpufreq: tegra186: Fix initial frequency

Commit 6cc3d0e9a097 ("cpufreq: tegra186: add
CPUFREQ_NEED_INITIAL_FREQ_CHECK flag") fixed CPUFREQ support for
Tegra186 but as a consequence the following warnings are now seen on
boot ...

 cpufreq: cpufreq_online: CPU0: Running at unlisted freq: 0 KHz
 cpufreq: cpufreq_online: CPU0: Unlisted initial frequency changed to: 2035200 KHz
 cpufreq: cpufreq_online: CPU1: Running at unlisted freq: 0 KHz
 cpufreq: cpufreq_online: CPU1: Unlisted initial frequency changed to: 2035200 KHz
 cpufreq: cpufreq_online: CPU2: Running at unlisted freq: 0 KHz
 cpufreq: cpufreq_online: CPU2: Unlisted initial frequency changed to: 2035200 KHz
 cpufreq: cpufreq_online: CPU3: Running at unlisted freq: 0 KHz
 cpufreq: cpufreq_online: CPU3: Unlisted initial frequency changed to: 2035200 KHz
 cpufreq: cpufreq_online: CPU4: Running at unlisted freq: 0 KHz
 cpufreq: cpufreq_online: CPU4: Unlisted initial frequency changed to: 2035200 KHz
 cpufreq: cpufreq_online: CPU5: Running at unlisted freq: 0 KHz
 cpufreq: cpufreq_online: CPU5: Unlisted initial frequency changed to: 2035200 KHz

Although we could fix this by adding a 'get' operator for the Tegra186
CPUFREQ driver, there is really little point because the CPUFREQ on
Tegra186 is set by writing a value stored in the frequency table to a
register and we just need to set the initial frequency. So for Tegra186
the simplest way to fix this is read the register that sets the
frequency for each CPU and set the initial frequency when initialising
the CPUFREQ driver.

Signed-off-by: Jon Hunter <jonathanh@...dia.com>
---
 drivers/cpufreq/tegra186-cpufreq.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/cpufreq/tegra186-cpufreq.c b/drivers/cpufreq/tegra186-cpufreq.c
index 3d2f143748ef..c44190ce3f03 100644
--- a/drivers/cpufreq/tegra186-cpufreq.c
+++ b/drivers/cpufreq/tegra186-cpufreq.c
@@ -59,6 +59,7 @@ static int tegra186_cpufreq_init(struct cpufreq_policy *policy)
 		struct tegra186_cpufreq_cluster *cluster = &data->clusters[i];
 		const struct tegra186_cpufreq_cluster_info *info =
 			cluster->info;
+		u32 edvd_val;
 		int core;
 
 		for (core = 0; core < ARRAY_SIZE(info->cpus); core++) {
@@ -71,6 +72,13 @@ static int tegra186_cpufreq_init(struct cpufreq_policy *policy)
 		policy->driver_data =
 			data->regs + info->offset + EDVD_CORE_VOLT_FREQ(core);
 		policy->freq_table = cluster->table;
+
+		edvd_val = readl(policy->driver_data);
+
+		for (i = 0; cluster->table[i].frequency != CPUFREQ_TABLE_END; i++) {
+			if (cluster->table[i].driver_data == edvd_val)
+				policy->cur = cluster->table[i].frequency;
+		}
 		break;
 	}
 
-- 
2.17.1