linux-kernel - [PATCH v3 4/4] soc: samsung: exynos-asv: Update Energy Model after adjusting voltage

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Message-Id: <20240328085112.3873050-5-lukasz.luba@arm.com>
Date: Thu, 28 Mar 2024 08:51:12 +0000
From: Lukasz Luba <lukasz.luba@....com>
To: linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org,
	rafael@...nel.org
Cc: lukasz.luba@....com,
	dietmar.eggemann@....com,
	linux-arm-kernel@...ts.infradead.org,
	sboyd@...nel.org,
	nm@...com,
	linux-samsung-soc@...r.kernel.org,
	daniel.lezcano@...aro.org,
	viresh.kumar@...aro.org,
	krzysztof.kozlowski@...aro.org,
	alim.akhtar@...sung.com,
	m.szyprowski@...sung.com,
	mhiramat@...nel.org
Subject: [PATCH v3 4/4] soc: samsung: exynos-asv: Update Energy Model after adjusting voltage

When the voltage for OPPs is adjusted there is a need to also update
Energy Model framework. The EM data contains power values which depend
on voltage values. The EM structure is used for thermal (IPA governor)
and in scheduler task placement (EAS) so it should reflect the real HW
model as best as possible to operate properly.

Based on data on Exynos5422 ASV tables the maximum power difference might
be ~29%. An Odroid-XU4 (with a random sample SoC in this chip lottery)
showed power difference for some OPPs ~20%. Therefore, it's worth to
update the EM.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Signed-off-by: Lukasz Luba <lukasz.luba@....com>
---
 drivers/soc/samsung/exynos-asv.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/samsung/exynos-asv.c b/drivers/soc/samsung/exynos-asv.c
index d60af8acc3916..d6d003e3a81ab 100644
--- a/drivers/soc/samsung/exynos-asv.c
+++ b/drivers/soc/samsung/exynos-asv.c
@@ -11,6 +11,7 @@
 
 #include <linux/cpu.h>
 #include <linux/device.h>
+#include <linux/energy_model.h>
 #include <linux/errno.h>
 #include <linux/of.h>
 #include <linux/pm_opp.h>
@@ -97,9 +98,17 @@ static int exynos_asv_update_opps(struct exynos_asv *asv)
 			last_opp_table = opp_table;
 
 			ret = exynos_asv_update_cpu_opps(asv, cpu);
-			if (ret < 0)
+			if (!ret) {
+				/*
+				 * When the voltage for OPPs could be changed,
+				 * make sure to update the EM power values, to
+				 * reflect the reality and not use stale data.
+				 */
+				em_dev_update_chip_binning(cpu);
+			} else {
 				dev_err(asv->dev, "Couldn't udate OPPs for cpu%d\n",
 					cpuid);
+			}
 		}
 
 		dev_pm_opp_put_opp_table(opp_table);
-- 
2.25.1