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Commit 1cf1bef6 authored by Rama Aparna Mallavarapu's avatar Rama Aparna Mallavarapu
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PM / devfreq: bw_hwmon: Add HW offload support to governor 



Some HW monitors can do a better job of the sampling and the threshold
checking than the SW implementation in the governor.  Update the governor's
API to add support for them.

Change-Id: Id4b5593a5ed3290684ba43ebebe2466ba0b730b6
Signed-off-by: default avatarSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: default avatarRama Aparna Mallavarapu <aparnam@codeaurora.org>
parent c2d48d46

drivers/devfreq/governor_bw_hwmon.c

+73 −16
Original line number Diff line number Diff line
@@ -55,8 +55,6 @@ struct hwmon_node { 
	unsigned long hyst_trig_win;

	unsigned long hyst_en;

	unsigned long prev_req;

	unsigned long up_wake_mbps;

	unsigned long down_wake_mbps;

	unsigned int wake;

	unsigned int down_cnt;

	ktime_t prev_ts;
@@ -181,7 +179,7 @@ static unsigned int mbps_to_bytes(unsigned long mbps, unsigned int ms) 
	return mbps;

}



static int __bw_hwmon_sample_end(struct bw_hwmon *hwmon)

static int __bw_hwmon_sw_sample_end(struct bw_hwmon *hwmon)

{

	struct devfreq *df;

	struct hwmon_node *node;
@@ -210,9 +208,9 @@ static int __bw_hwmon_sample_end(struct bw_hwmon *hwmon) 
	 * bandwidth usage and do the bandwidth calculation based on just

	 * this micro sample.

	 */

	if (mbps > node->up_wake_mbps) {

	if (mbps > node->hw->up_wake_mbps) {

		wake = UP_WAKE;

	} else if (mbps < node->down_wake_mbps) {

	} else if (mbps < node->hw->down_wake_mbps) {

		if (node->down_cnt)

			node->down_cnt--;

		if (node->down_cnt <= 0)
@@ -231,6 +229,50 @@ static int __bw_hwmon_sample_end(struct bw_hwmon *hwmon) 
	return wake;

}



static int __bw_hwmon_hw_sample_end(struct bw_hwmon *hwmon)

{

	struct devfreq *df;

	struct hwmon_node *node;

	unsigned long bytes, mbps;

	int wake = 0;



	df = hwmon->df;

	node = df->data;



	/*

	 * If this read is in response to an IRQ, the HW monitor should

	 * return the measurement in the micro sample that triggered the IRQ.

	 * Otherwise, it should return the maximum measured value in any

	 * micro sample since the last time we called get_bytes_and_clear()

	 */

	bytes = hwmon->get_bytes_and_clear(hwmon);

	mbps = bytes_to_mbps(bytes, node->sample_ms * USEC_PER_MSEC);

	node->max_mbps = mbps;



	if (mbps > node->hw->up_wake_mbps)

		wake = UP_WAKE;

	else if (mbps < node->hw->down_wake_mbps)

		wake = DOWN_WAKE;



	node->wake = wake;

	node->sampled = true;



	trace_bw_hwmon_meas(dev_name(df->dev.parent),

				mbps,

				node->sample_ms * USEC_PER_MSEC,

				wake);



	return 1;

}



static int __bw_hwmon_sample_end(struct bw_hwmon *hwmon)

{

	if (hwmon->set_hw_events)

		return __bw_hwmon_hw_sample_end(hwmon);

	else

		return __bw_hwmon_sw_sample_end(hwmon);

}



int bw_hwmon_sample_end(struct bw_hwmon *hwmon)

{

	unsigned long flags;
@@ -265,12 +307,14 @@ static unsigned long get_bw_and_set_irq(struct hwmon_node *node, 
	struct bw_hwmon *hw = node->hw;

	unsigned int new_bw, io_percent = node->io_percent;

	ktime_t ts;

	unsigned int ms;

	unsigned int ms = 0;



	spin_lock_irqsave(&irq_lock, flags);



	if (!hw->set_hw_events) {

		ts = ktime_get();

		ms = ktime_to_ms(ktime_sub(ts, node->prev_ts));

	}

	if (!node->sampled || ms >= node->sample_ms)

		__bw_hwmon_sample_end(node->hw);

	node->sampled = false;
@@ -367,9 +411,10 @@ static unsigned long get_bw_and_set_irq(struct hwmon_node *node, 


	/* Stretch the short sample window size, if the traffic is too low */

	if (meas_mbps < MIN_MBPS) {

		node->up_wake_mbps = (max(MIN_MBPS, req_mbps)

		hw->up_wake_mbps = (max(MIN_MBPS, req_mbps)

					* (100 + node->up_thres)) / 100;

		node->down_wake_mbps = 0;

		hw->down_wake_mbps = 0;

		hw->undo_over_req_mbps = 0;

		thres = mbps_to_bytes(max(MIN_MBPS, req_mbps / 2),

					node->sample_ms);

	} else {
@@ -380,13 +425,22 @@ static unsigned long get_bw_and_set_irq(struct hwmon_node *node, 
		 * reduce the vote based on the measured mbps being less than

		 * the previous measurement that caused the "over request".

		 */

		node->up_wake_mbps = (req_mbps * (100 + node->up_thres)) / 100;

		node->down_wake_mbps = (meas_mbps * node->down_thres) / 100;

		hw->up_wake_mbps = (req_mbps * (100 + node->up_thres)) / 100;

		hw->down_wake_mbps = (meas_mbps * node->down_thres) / 100;

		if (node->wake == UP_WAKE)

			hw->undo_over_req_mbps = min(req_mbps, meas_mbps_zone);

		else

			hw->undo_over_req_mbps = 0;

		thres = mbps_to_bytes(meas_mbps, node->sample_ms);

	}

	node->down_cnt = node->down_count;



	if (hw->set_hw_events) {

		hw->down_cnt = node->down_count;

		hw->set_hw_events(hw, node->sample_ms);

	} else {

		node->down_cnt = node->down_count;

		node->bytes = hw->set_thres(hw, thres);

	}



	node->wake = 0;

	node->prev_req = req_mbps;
@@ -411,8 +465,8 @@ static unsigned long get_bw_and_set_irq(struct hwmon_node *node, 
	trace_bw_hwmon_update(dev_name(node->hw->df->dev.parent),

				new_bw,

				*freq,

				node->up_wake_mbps,

				node->down_wake_mbps);

				hw->up_wake_mbps,

				hw->down_wake_mbps);

	return req_mbps;

}
@@ -482,6 +536,9 @@ static int start_monitor(struct devfreq *df, bool init) 
		node->resume_freq = 0;

		node->resume_ab = 0;

		mbps = (df->previous_freq * node->io_percent) / 100;

		hw->up_wake_mbps = mbps;

		hw->down_wake_mbps = MIN_MBPS;

		hw->undo_over_req_mbps = 0;

		ret = hw->start_hwmon(hw, mbps);

	} else {

		ret = hw->resume_hwmon(hw);

drivers/devfreq/governor_bw_hwmon.h

+7 −0
Original line number Diff line number Diff line
@@ -40,6 +40,8 @@ struct bw_hwmon { 
	int (*suspend_hwmon)(struct bw_hwmon *hw);

	int (*resume_hwmon)(struct bw_hwmon *hw);

	unsigned long (*set_thres)(struct bw_hwmon *hw, unsigned long bytes);

	unsigned long (*set_hw_events)(struct bw_hwmon *hw,

					unsigned int sample_ms);

	unsigned long (*get_bytes_and_clear)(struct bw_hwmon *hw);

	int (*set_throttle_adj)(struct bw_hwmon *hw, uint adj);

	u32 (*get_throttle_adj)(struct bw_hwmon *hw);
@@ -47,6 +49,11 @@ struct bw_hwmon { 
	struct device_node *of_node;

	struct devfreq_governor *gov;



	unsigned long up_wake_mbps;

	unsigned long undo_over_req_mbps;

	unsigned long down_wake_mbps;

	unsigned int down_cnt;



	struct devfreq *df;

};