linux-kernel - [PATCH] powercap: DTPM: Fix unneeded conversion to micro-Watts

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Message-Id: <20231127092819.2019744-1-lukasz.luba@arm.com>
Date:   Mon, 27 Nov 2023 09:28:19 +0000
From:   Lukasz Luba <lukasz.luba@....com>
To:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        daniel.lezcano@...aro.org
Cc:     lukasz.luba@....com, rafael@...nel.org, stable@...r.kernel.org
Subject: [PATCH] powercap: DTPM: Fix unneeded conversion to micro-Watts

The Power values coming from the Energy Model are already in uW.
The PowerCap and DTPM framework operate on uW, thus all places should
just use the values from EM. Fix the code which left and still does
the unneeded conversion.

Fixes: ae6ccaa65038 (PM: EM: convert power field to micro-Watts precision and align drivers)
Cc: <stable@...r.kernel.org> # v5.19+
Signed-off-by: Lukasz Luba <lukasz.luba@....com>
---
Hi Daniel,

I have found an issue due to the uW in the EM. My apologies for that.
I have check those with the Rockpi dev board with your DTPM module there.
BTW, if you like to check the DTPM_devfreq there, you can apply that
patch. It should create EM for your GPU there and setup DTPM GPU:
https://lore.kernel.org/all/20231127081511.1911706-1-lukasz.luba@arm.com/

Regards,
Lukasz


 drivers/powercap/dtpm_cpu.c     |  6 +-----
 drivers/powercap/dtpm_devfreq.c | 11 +++--------
 2 files changed, 4 insertions(+), 13 deletions(-)

diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
index 2ff7717530bf..8a2f18fa3faf 100644
--- a/drivers/powercap/dtpm_cpu.c
+++ b/drivers/powercap/dtpm_cpu.c
@@ -24,7 +24,6 @@
 #include <linux/of.h>
 #include <linux/pm_qos.h>
 #include <linux/slab.h>
-#include <linux/units.h>
 
 struct dtpm_cpu {
 	struct dtpm dtpm;
@@ -104,8 +103,7 @@ static u64 get_pd_power_uw(struct dtpm *dtpm)
 		if (pd->table[i].frequency < freq)
 			continue;
 
-		return scale_pd_power_uw(pd_mask, pd->table[i].power *
-					 MICROWATT_PER_MILLIWATT);
+		return scale_pd_power_uw(pd_mask, pd->table[i].power);
 	}
 
 	return 0;
@@ -122,11 +120,9 @@ static int update_pd_power_uw(struct dtpm *dtpm)
 	nr_cpus = cpumask_weight(&cpus);
 
 	dtpm->power_min = em->table[0].power;
-	dtpm->power_min *= MICROWATT_PER_MILLIWATT;
 	dtpm->power_min *= nr_cpus;
 
 	dtpm->power_max = em->table[em->nr_perf_states - 1].power;
-	dtpm->power_max *= MICROWATT_PER_MILLIWATT;
 	dtpm->power_max *= nr_cpus;
 
 	return 0;
diff --git a/drivers/powercap/dtpm_devfreq.c b/drivers/powercap/dtpm_devfreq.c
index 91276761a31d..612c3b59dd5b 100644
--- a/drivers/powercap/dtpm_devfreq.c
+++ b/drivers/powercap/dtpm_devfreq.c
@@ -39,10 +39,8 @@ static int update_pd_power_uw(struct dtpm *dtpm)
 	struct em_perf_domain *pd = em_pd_get(dev);
 
 	dtpm->power_min = pd->table[0].power;
-	dtpm->power_min *= MICROWATT_PER_MILLIWATT;
 
 	dtpm->power_max = pd->table[pd->nr_perf_states - 1].power;
-	dtpm->power_max *= MICROWATT_PER_MILLIWATT;
 
 	return 0;
 }
@@ -54,13 +52,10 @@ static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
 	struct device *dev = devfreq->dev.parent;
 	struct em_perf_domain *pd = em_pd_get(dev);
 	unsigned long freq;
-	u64 power;
 	int i;
 
 	for (i = 0; i < pd->nr_perf_states; i++) {
-
-		power = pd->table[i].power * MICROWATT_PER_MILLIWATT;
-		if (power > power_limit)
+		if (pd->table[i].power > power_limit)
 			break;
 	}
 
@@ -68,7 +63,7 @@ static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
 
 	dev_pm_qos_update_request(&dtpm_devfreq->qos_req, freq);
 
-	power_limit = pd->table[i - 1].power * MICROWATT_PER_MILLIWATT;
+	power_limit = pd->table[i - 1].power;
 
 	return power_limit;
 }
@@ -110,7 +105,7 @@ static u64 get_pd_power_uw(struct dtpm *dtpm)
 		if (pd->table[i].frequency < freq)
 			continue;
 
-		power = pd->table[i].power * MICROWATT_PER_MILLIWATT;
+		power = pd->table[i].power;
 		power *= status.busy_time;
 		power >>= 10;
 
-- 
2.25.1