linux-kernel - [PATCH 2/2] cpufreq: brcmstb-avs-cpufreq: properly retrieve P-state upon suspend

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Date:   Mon, 19 Dec 2016 12:10:28 -0800
From:   Markus Mayer <code@...yer.net>
To:     Viresh Kumar <viresh.kumar@...aro.org>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>
Cc:     Power Management List <linux-pm@...r.kernel.org>,
        Broadcom Kernel List <bcm-kernel-feedback-list@...adcom.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Markus Mayer <mmayer@...adcom.com>
Subject: [PATCH 2/2] cpufreq: brcmstb-avs-cpufreq: properly retrieve P-state upon suspend

From: Markus Mayer <mmayer@...adcom.com>

The AVS GET_PMAP command does return a P-state along with the P-map
information. However, that P-state is the initial P-state when the
P-map was first downloaded to AVS. It is *not* the current P-state.

Therefore, we explicitly retrieve the P-state using the GET_PSTATE
command.

Signed-off-by: Markus Mayer <mmayer@...adcom.com>
---
 drivers/cpufreq/brcmstb-avs-cpufreq.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/brcmstb-avs-cpufreq.c b/drivers/cpufreq/brcmstb-avs-cpufreq.c
index 2c6e325..c943606 100644
--- a/drivers/cpufreq/brcmstb-avs-cpufreq.c
+++ b/drivers/cpufreq/brcmstb-avs-cpufreq.c
@@ -784,8 +784,19 @@ static int brcm_avs_target_index(struct cpufreq_policy *policy,
 static int brcm_avs_suspend(struct cpufreq_policy *policy)
 {
 	struct private_data *priv = policy->driver_data;
+	int ret;
+
+	ret = brcm_avs_get_pmap(priv, &priv->pmap);
+	if (ret)
+		return ret;
 
-	return brcm_avs_get_pmap(priv, &priv->pmap);
+	/*
+	 * We can't use the P-state returned by brcm_avs_get_pmap(), since
+	 * that's the initial P-state from when the P-map was downloaded to the
+	 * AVS co-processor, not necessarily the P-state we are running at now.
+	 * So, we get the current P-state explicitly.
+	 */
+	return brcm_avs_get_pstate(priv, &priv->pmap.state);
 }
 
 static int brcm_avs_resume(struct cpufreq_policy *policy)
-- 
2.7.4