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soc: samsung: exynos-asv: Update Energy Model after adjusting voltage
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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@linaro.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Lukasz Luba authored and Rafael J. Wysocki committed Apr 8, 2024
1 parent cf61d53 commit a5bb5e0
Showing 1 changed file with 9 additions and 1 deletion.
10 changes: 9 additions & 1 deletion drivers/soc/samsung/exynos-asv.c
Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -97,9 +98,16 @@ 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) {
/*
* Update EM power values since OPP
* voltage values may have changed.
*/
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);
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