drm/panthor: call into devfreq for current frequency

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: Chia-I Wu <[e-mail]>
Reviewed-by: Steven Price <[e-mail]>
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Reviewed-by: Karunika Choo <[e-mail]>
Reviewed-by: Liviu Dudau <[e-mail]>
Signed-off-by: Nicolas Frattaroli <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Liviu Dudau <[e-mail]>

drivers/gpu/drm/panthor/panthor_devfreq.c

···
 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;
 
···
 	dev_pm_opp_put(opp);
 
 	err = dev_pm_opp_set_rate(dev, *freq);
-	if (!err)
-		ptdev->current_frequency = *freq;
 
 	return err;
 }
···
 	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)
···
 		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
···
 	pdevfreq->last_busy_state = false;
 
 	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->devfreq)
+		return 0;
+
+	ret = pdevfreq->devfreq->profile->get_cur_freq(ptdev->base.dev, &freq);
+	if (ret)
+		return 0;
+
+	return freq;
 }

drivers/gpu/drm/panthor/panthor_devfreq.h

···
 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__ */

drivers/gpu/drm/panthor/panthor_device.h

···
 	/** @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;
 

drivers/gpu/drm/panthor/panthor_drv.c

···
 #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"
···
 		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)