[PATCH v4 6/8] drm/panthor: call into devfreq for current frequency

Nicolas Frattaroli
2025-09-23T11:41:25Z

As it stands, panthor keeps a cached current frequency value for when it
wants to retrieve it. This doesn't work well for when things might
switch frequency without panthor's knowledge.

Instead, implement the get_cur_freq operation, and expose it through a
helper function to the rest of panthor.

Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/panthor/panthor_devfreq.c | 33 +++++++++++++++++++++++++++----
drivers/gpu/drm/panthor/panthor_devfreq.h | 2 ++
drivers/gpu/drm/panthor/panthor_device.h | 3 ---
drivers/gpu/drm/panthor/panthor_drv.c | 4 +++-
4 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_devfreq.c b/drivers/gpu/drm/panthor/panthor_devfreq.c
index 3686515d368db5bb329f4858d4a7247a4957cc24..8903f60c0a3f06313ac2008791c210ff32b6bd52 100644
--- a/drivers/gpu/drm/panthor/panthor_devfreq.c
+++ b/drivers/gpu/drm/panthor/panthor_devfreq.c
@@ -62,7 +62,6 @@ static void panthor_devfreq_update_utilization(struct panthor_devfreq *pdevfreq)
static int panthor_devfreq_target(struct device *dev, unsigned long *freq,
u32 flags)
{
- struct panthor_device *ptdev = dev_get_drvdata(dev);
struct dev_pm_opp *opp;
int err;

@@ -72,8 +71,6 @@ static int panthor_devfreq_target(struct device *dev, unsigned long *freq,
dev_pm_opp_put(opp);

err = dev_pm_opp_set_rate(dev, *freq);
- if (!err)
- ptdev->current_frequency = *freq;

return err;
}
@@ -115,11 +112,21 @@ static int panthor_devfreq_get_dev_status(struct device *dev,
return 0;
}

+static int panthor_devfreq_get_cur_freq(struct device *dev, unsigned long *freq)
+{
+ struct panthor_device *ptdev = dev_get_drvdata(dev);
+
+ *freq = clk_get_rate(ptdev->clks.core);
+
+ return 0;
+}
+
static struct devfreq_dev_profile panthor_devfreq_profile = {
.timer = DEVFREQ_TIMER_DELAYED,
.polling_ms = 50, /* ~3 frames */
.target = panthor_devfreq_target,
.get_dev_status = panthor_devfreq_get_dev_status,
+ .get_cur_freq = panthor_devfreq_get_cur_freq,
};

int panthor_devfreq_init(struct panthor_device *ptdev)
@@ -198,7 +205,6 @@ int panthor_devfreq_init(struct panthor_device *ptdev)
return PTR_ERR(opp);

panthor_devfreq_profile.initial_freq = cur_freq;
- ptdev->current_frequency = cur_freq;

/*
* Set the recommend OPP this will enable and configure the regulator
@@ -296,3 +302,22 @@ void panthor_devfreq_record_idle(struct panthor_device *ptdev)

spin_unlock_irqrestore(&pdevfreq->lock, irqflags);
}
+
+unsigned long panthor_devfreq_get_freq(struct panthor_device *ptdev)
+{
+ struct panthor_devfreq *pdevfreq = ptdev->devfreq;
+ unsigned long freq = 0;
+ int ret;
+
+ if (!pdevfreq || !pdevfreq->devfreq)
+ return 0;
+
+ if (pdevfreq->devfreq->profile->get_cur_freq) {
+ ret = pdevfreq->devfreq->profile->get_cur_freq(ptdev->base.dev,
+ &freq);
+ if (ret)
+ return 0;
+ }
+
+ return freq;
+}
diff --git a/drivers/gpu/drm/panthor/panthor_devfreq.h b/drivers/gpu/drm/panthor/panthor_devfreq.h
index b7631de695f7d79456478c87e8af5dc47673cd1d..f8e29e02f66cb3281ed4bb4c75cda9bd4df82b92 100644
--- a/drivers/gpu/drm/panthor/panthor_devfreq.h
+++ b/drivers/gpu/drm/panthor/panthor_devfreq.h
@@ -18,4 +18,6 @@ void panthor_devfreq_suspend(struct panthor_device *ptdev);
void panthor_devfreq_record_busy(struct panthor_device *ptdev);
void panthor_devfreq_record_idle(struct panthor_device *ptdev);

+unsigned long panthor_devfreq_get_freq(struct panthor_device *ptdev);
+
#endif /* __PANTHOR_DEVFREQ_H__ */
diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
index 9f0649ecfc4fc697a21a8b2fc4dd89c8ecf298df..f32c1868bf6d782d99df9dbd0babcea049c917e0 100644
--- a/drivers/gpu/drm/panthor/panthor_device.h
+++ b/drivers/gpu/drm/panthor/panthor_device.h
@@ -214,9 +214,6 @@ struct panthor_device {
/** @profile_mask: User-set profiling flags for job accounting. */
u32 profile_mask;

- /** @current_frequency: Device clock frequency at present. Set by DVFS*/
- unsigned long current_frequency;
-
/** @fast_rate: Maximum device clock frequency. Set by DVFS */
unsigned long fast_rate;

diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index ea4a37b566a8b215f2b7a09c333a696f1dcdb58f..4d59d94c353c3ca76f4b98a411c8f8284efafd08 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -25,6 +25,7 @@
#include <drm/gpu_scheduler.h>
#include <drm/panthor_drm.h>

+#include "panthor_devfreq.h"
#include "panthor_device.h"
#include "panthor_fw.h"
#include "panthor_gem.h"
@@ -1519,7 +1520,8 @@ static void panthor_gpu_show_fdinfo(struct panthor_device *ptdev,
drm_printf(p, "drm-cycles-panthor:\t%llu\n", pfile->stats.cycles);

drm_printf(p, "drm-maxfreq-panthor:\t%lu Hz\n", ptdev->fast_rate);
- drm_printf(p, "drm-curfreq-panthor:\t%lu Hz\n", ptdev->current_frequency);
+ drm_printf(p, "drm-curfreq-panthor:\t%lu Hz\n",
+ panthor_devfreq_get_freq(ptdev));
}

static void panthor_show_internal_memory_stats(struct drm_printer *p, struct drm_file *file)

--
2.51.0