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Commit f7e4bb44 authored by Mihir Patel's avatar Mihir Patel Committed by Matt Wagantall
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msm: kgsl: Dynamic AB voting based on actual bus transactions 



Right now AB vote is calulated as a percentage of total possible BW
which causes higher AB vote than actual GPU bus transactions in some
use cases. We can calculate actual GPU bus BW if we know bus_width
for the target. This change will derive AB vote based on bus_width
defined in dtsi and VBIF counters.

Define bus_width in number of bytes in target gpu dtsi file to use
this new AB vote calculation.

Change-Id: I75d19c18649d9a87d20e3dbf7b623b772265fb5b
Signed-off-by: default avatarMihir Patel <mihirp@codeaurora.org>
parent 2f6ae135

Documentation/devicetree/bindings/gpu/adreno.txt

+2 −0
Original line number Diff line number Diff line
@@ -83,6 +83,8 @@ Optional Properties: 
- qcom,initial-powerlevel: This value indicates which qcom,gpu-pwrlevel should be used at start time

			   and when coming back out of resume

- qcom,bus-control:	   Boolean. Enables an independent bus vote from the gpu frequency

- qcom,bus-width:	   Bus width in number of bytes. This enables dynamic AB bus voting based on

			   bus width and actual bus transactions.

- qcom,gpubw-dev:	   a phandle to a device representing bus bandwidth requirements

			   (see devdw.txt)

- qcom,idle-timeout:	   This property represents the time in microseconds for idle timeout.

drivers/devfreq/governor_gpubw_mon.c

+12 −2
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ 
#define HIST                    5

#define TARGET                  80

#define CAP                     75

/* AB vote is in multiple of BW_STEP Mega bytes */

#define BW_STEP                 160



static void _update_cutoff(struct devfreq_msm_adreno_tz_data *priv,

					unsigned int norm_max)
@@ -60,6 +62,7 @@ static int devfreq_gpubw_get_target(struct devfreq *df, 
	 */

	static int norm_ab_max = 300;

	int norm_ab;

	unsigned long ab_mbytes = 0;



	stats.private_data = &b;
@@ -104,8 +107,15 @@ static int devfreq_gpubw_get_target(struct devfreq *df, 
			bus_profile->flag = DEVFREQ_FLAG_SLOW_HINT;

	}



	/* Calculate the AB vote based on bus width if defined */

	if (priv->bus.width) {

		norm_ab =  (unsigned int)priv->bus.ram_time /

			(unsigned int) priv->bus.total_time;

		/* Calculate AB in Mega Bytes and roundup in BW_STEP */

		ab_mbytes = (norm_ab * priv->bus.width * 1000000ULL) >> 20;

		bus_profile->ab_mbytes = roundup(ab_mbytes, BW_STEP);

	} else if (bus_profile->flag) {

		/* Re-calculate the AB percentage for a new IB vote */

	if (bus_profile->flag) {

		norm_ab =  (unsigned int)priv->bus.ram_time /

			(unsigned int) priv->bus.total_time;

		if (norm_ab > norm_ab_max)

drivers/gpu/msm/kgsl_pwrctrl.c

+9 −1
Original line number Diff line number Diff line
@@ -168,8 +168,10 @@ static void _ab_buslevel_update(struct kgsl_pwrctrl *pwr, 
		return;

	if (ib == 0)

		*ab = 0;

	else if (!pwr->bus_percent_ab)

	else if ((!pwr->bus_percent_ab) && (!pwr->bus_ab_mbytes))

		*ab = DEFAULT_BUS_P * ib / 100;

	else if (pwr->bus_width)

		*ab = pwr->bus_ab_mbytes;

	else

		*ab = (pwr->bus_percent_ab * max_bw) / 100;
@@ -250,6 +252,8 @@ void kgsl_pwrctrl_buslevel_update(struct kgsl_device *device, 
	} else {

		/* If the bus is being turned off, reset to default level */

		pwr->bus_mod = 0;

		pwr->bus_percent_ab = 0;

		pwr->bus_ab_mbytes = 0;

	}

	trace_kgsl_buslevel(device, pwr->active_pwrlevel, buslevel);

	last_vote_buslevel = buslevel;
@@ -1548,6 +1552,10 @@ int kgsl_pwrctrl_init(struct kgsl_device *device) 


	/* Set if independent bus BW voting is supported */

	pwr->bus_control = pdata->bus_control;

	/* Bus width in bytes, set it to zero if not found */

	if (of_property_read_u32(pdev->dev.of_node, "qcom,bus-width",

		&pwr->bus_width))

		pwr->bus_width = 0;



	/* Check if gpu bandwidth vote device is defined in dts */

	gpubw_dev_node = of_parse_phandle(pdev->dev.of_node,

drivers/gpu/msm/kgsl_pwrctrl.h

+4 −0
Original line number Diff line number Diff line
@@ -108,6 +108,8 @@ struct kgsl_pwr_constraint { 
 * @bus_control - true if the bus calculation is independent

 * @bus_mod - modifier from the current power level for the bus vote

 * @bus_percent_ab - current percent of total possible bus usage

 * @bus_width - target specific bus width in number of bytes

 * @bus_ab_mbytes - AB vote in Mbytes for current bus usage

 * @bus_index - default bus index into the bus_ib table

 * @bus_ib - the set of unique ib requests needed for the bus calculation

 * @constraint - currently active power constraint
@@ -152,6 +154,8 @@ struct kgsl_pwrctrl { 
	bool bus_control;

	int bus_mod;

	unsigned int bus_percent_ab;

	unsigned int bus_width;

	unsigned long bus_ab_mbytes;

	struct device *devbw;

	unsigned int bus_index[KGSL_MAX_PWRLEVELS];

	uint64_t *bus_ib;

drivers/gpu/msm/kgsl_pwrscale.c

+2 −0
Original line number Diff line number Diff line
@@ -715,6 +715,7 @@ int kgsl_busmon_target(struct device *dev, unsigned long *freq, u32 flags) 


	if (pwr->bus_mod != b) {

		pwr->bus_percent_ab = device->pwrscale.bus_profile.percent_ab;

		pwr->bus_ab_mbytes =  device->pwrscale.bus_profile.ab_mbytes;

		kgsl_pwrctrl_buslevel_update(device, true);

	}
@@ -797,6 +798,7 @@ int kgsl_pwrscale_init(struct device *dev, const char *governor) 
		data->bus.num = out;

		data->bus.ib = &pwr->bus_ib[0];

		data->bus.index = &pwr->bus_index[0];

		data->bus.width = pwr->bus_width;

	} else

		data->bus.num = 0;