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Commit 2ad4263c authored by Rama Aparna Mallavarapu's avatar Rama Aparna Mallavarapu
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msm: devfreq_cpubw: Add devfreq driver for device bandwidth voting 



This driver registers itself as a devfreq device that allows devfreq
governors to make IB/AB bandwidth votes. This driver allows the governors
to be agnostic of the bandwidth voting APIs, the number of master ports or
slave ports, the actual port numbers, the system topology, the available
frequencies, etc.

Change-Id: If055ddd580afd41f9668b111e6c09a047488b2e0
Signed-off-by: default avatarSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: default avatarRama Aparna Mallavarapu <aparnam@codeaurora.org>
parent 593edff9

drivers/devfreq/Kconfig

+14 −0
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@@ -156,6 +156,20 @@ config DEVFREQ_SIMPLE_DEV 
	  Device driver for simple devices that control their frequency using

	  clock APIs and don't have any form of status reporting.



config QCOM_DEVFREQ_DEVBW

	bool "Qualcomm Technologies Inc. DEVFREQ device for device master <-> slave IB/AB BW voting"

	depends on ARCH_QCOM

	select DEVFREQ_GOV_PERFORMANCE

	select DEVFREQ_GOV_POWERSAVE

	select DEVFREQ_GOV_USERSPACE

	select DEVFREQ_GOV_CPUFREQ

	default n

	help

	  Different devfreq governors use this devfreq device to make CPU to

	  DDR IB/AB bandwidth votes. This driver provides a SoC topology

	  agnostic interface to so that some of the devfreq governors can be

	  shared across SoCs.



source "drivers/devfreq/event/Kconfig"



endif # PM_DEVFREQ

drivers/devfreq/Makefile

+1 −0
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@@ -14,6 +14,7 @@ obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o 
obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ)	+= rk3399_dmc.o

obj-$(CONFIG_ARM_TEGRA_DEVFREQ)		+= tegra-devfreq.o

obj-$(CONFIG_ARM_QCOM_DEVFREQ_FW)	+= devfreq_qcom_fw.o

obj-$(CONFIG_QCOM_DEVFREQ_DEVBW)		+= devfreq_devbw.o

obj-$(CONFIG_DEVFREQ_SIMPLE_DEV)	+= devfreq_simple_dev.o



# DEVFREQ Event Drivers

drivers/devfreq/devfreq_devbw.c

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// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (c) 2013-2014, 2019, The Linux Foundation. All rights reserved.

 */



#define pr_fmt(fmt) "devbw: " fmt



#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/io.h>

#include <linux/delay.h>

#include <linux/ktime.h>

#include <linux/time.h>

#include <linux/err.h>

#include <linux/errno.h>

#include <linux/mutex.h>

#include <linux/interrupt.h>

#include <linux/devfreq.h>

#include <linux/of.h>

#include <trace/events/power.h>

#include <linux/msm-bus.h>

#include <linux/msm-bus-board.h>



/* Has to be ULL to prevent overflow where this macro is used. */

#define MBYTE (1ULL << 20)

#define MAX_PATHS	2

#define DBL_BUF		2



struct dev_data {

	struct msm_bus_vectors vectors[MAX_PATHS * DBL_BUF];

	struct msm_bus_paths bw_levels[DBL_BUF];

	struct msm_bus_scale_pdata bw_data;

	int num_paths;

	u32 bus_client;

	int cur_idx;

	int cur_ab;

	int cur_ib;

	long gov_ab;

	struct devfreq *df;

	struct devfreq_dev_profile dp;

};



static int set_bw(struct device *dev, int new_ib, int new_ab)

{

	struct dev_data *d = dev_get_drvdata(dev);

	int i, ret;



	if (d->cur_ib == new_ib && d->cur_ab == new_ab)

		return 0;



	i = (d->cur_idx + 1) % DBL_BUF;



	d->bw_levels[i].vectors[0].ib = new_ib * MBYTE;

	d->bw_levels[i].vectors[0].ab = new_ab / d->num_paths * MBYTE;

	d->bw_levels[i].vectors[1].ib = new_ib * MBYTE;

	d->bw_levels[i].vectors[1].ab = new_ab / d->num_paths * MBYTE;



	dev_dbg(dev, "BW MBps: AB: %d IB: %d\n", new_ab, new_ib);



	ret = msm_bus_scale_client_update_request(d->bus_client, i);

	if (ret) {

		dev_err(dev, "bandwidth request failed (%d)\n", ret);

	} else {

		d->cur_idx = i;

		d->cur_ib = new_ib;

		d->cur_ab = new_ab;

	}



	return ret;

}



static void find_freq(struct devfreq_dev_profile *p, unsigned long *freq,

			u32 flags)

{

	int i;

	unsigned long atmost, atleast, f;



	atmost = p->freq_table[0];

	atleast = p->freq_table[p->max_state-1];

	for (i = 0; i < p->max_state; i++) {

		f = p->freq_table[i];

		if (f <= *freq)

			atmost = max(f, atmost);

		if (f >= *freq)

			atleast = min(f, atleast);

	}



	if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND)

		*freq = atmost;

	else

		*freq = atleast;

}



static int devbw_target(struct device *dev, unsigned long *freq, u32 flags)

{

	struct dev_data *d = dev_get_drvdata(dev);



	find_freq(&d->dp, freq, flags);

	return set_bw(dev, *freq, d->gov_ab);

}



static int devbw_get_dev_status(struct device *dev,

				struct devfreq_dev_status *stat)

{

	struct dev_data *d = dev_get_drvdata(dev);



	stat->private_data = &d->gov_ab;

	return 0;

}



#define PROP_PORTS "qcom,src-dst-ports"

#define PROP_TBL "qcom,bw-tbl"

#define PROP_ACTIVE "qcom,active-only"



int devfreq_add_devbw(struct device *dev)

{

	struct dev_data *d;

	struct devfreq_dev_profile *p;

	u32 *data, ports[MAX_PATHS * 2];

	const char *gov_name;

	int ret, len, i, num_paths;



	d = devm_kzalloc(dev, sizeof(*d), GFP_KERNEL);

	if (!d)

		return -ENOMEM;

	dev_set_drvdata(dev, d);



	if (of_find_property(dev->of_node, PROP_PORTS, &len)) {

		len /= sizeof(ports[0]);

		if (len % 2 || len > ARRAY_SIZE(ports)) {

			dev_err(dev, "Unexpected number of ports\n");

			return -EINVAL;

		}



		ret = of_property_read_u32_array(dev->of_node, PROP_PORTS,

						 ports, len);

		if (ret)

			return ret;



		num_paths = len / 2;

	} else {

		return -EINVAL;

	}



	d->bw_levels[0].vectors = &d->vectors[0];

	d->bw_levels[1].vectors = &d->vectors[MAX_PATHS];

	d->bw_data.usecase = d->bw_levels;

	d->bw_data.num_usecases = ARRAY_SIZE(d->bw_levels);

	d->bw_data.name = dev_name(dev);

	d->bw_data.active_only = of_property_read_bool(dev->of_node,

							PROP_ACTIVE);



	for (i = 0; i < num_paths; i++) {

		d->bw_levels[0].vectors[i].src = ports[2 * i];

		d->bw_levels[0].vectors[i].dst = ports[2 * i + 1];

		d->bw_levels[1].vectors[i].src = ports[2 * i];

		d->bw_levels[1].vectors[i].dst = ports[2 * i + 1];

	}

	d->bw_levels[0].num_paths = num_paths;

	d->bw_levels[1].num_paths = num_paths;

	d->num_paths = num_paths;



	p = &d->dp;

	p->polling_ms = 50;

	p->target = devbw_target;

	p->get_dev_status = devbw_get_dev_status;



	if (of_find_property(dev->of_node, PROP_TBL, &len)) {

		len /= sizeof(*data);

		data = devm_kzalloc(dev, len * sizeof(*data), GFP_KERNEL);

		if (!data)

			return -ENOMEM;



		p->freq_table = devm_kzalloc(dev,

					     len * sizeof(*p->freq_table),

					     GFP_KERNEL);

		if (!p->freq_table)

			return -ENOMEM;



		ret = of_property_read_u32_array(dev->of_node, PROP_TBL,

						 data, len);

		if (ret)

			return ret;



		for (i = 0; i < len; i++)

			p->freq_table[i] = data[i];

		p->max_state = len;

	}



	d->bus_client = msm_bus_scale_register_client(&d->bw_data);

	if (!d->bus_client) {

		dev_err(dev, "Unable to register bus client\n");

		return -ENODEV;

	}



	if (of_property_read_string(dev->of_node, "governor", &gov_name))

		gov_name = "performance";



	d->df = devfreq_add_device(dev, p, gov_name, NULL);

	if (IS_ERR(d->df)) {

		msm_bus_scale_unregister_client(d->bus_client);

		return PTR_ERR(d->df);

	}



	return 0;

}



static int devfreq_devbw_probe(struct platform_device *pdev)

{

	return devfreq_add_devbw(&pdev->dev);

}



int devfreq_remove_devbw(struct device *dev)

{

	struct dev_data *d = dev_get_drvdata(dev);



	msm_bus_scale_unregister_client(d->bus_client);

	devfreq_remove_device(d->df);

	return 0;

}



static int devfreq_devbw_remove(struct platform_device *pdev)

{

	return devfreq_remove_devbw(&pdev->dev);

}



static const struct of_device_id devbw_match_table[] = {

	{ .compatible = "qcom,devbw" },

	{}

};



static struct platform_driver devbw_driver = {

	.probe = devfreq_devbw_probe,

	.remove = devfreq_devbw_remove,

	.driver = {

		.name = "devbw",

		.of_match_table = devbw_match_table,

	},

};



module_platform_driver(devbw_driver);

MODULE_DESCRIPTION("Device DDR bandwidth voting driver MSM SoCs");

MODULE_LICENSE("GPL v2");

include/soc/qcom/devfreq_devbw.h

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/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Copyright (c) 2014, 2019, The Linux Foundation. All rights reserved.

 */



#ifndef _DEVFREQ_DEVBW_H

#define _DEVFREQ_DEVBW_H



#include <linux/devfreq.h>



#ifdef CONFIG_MSM_DEVFREQ_DEVBW

int devfreq_add_devbw(struct device *dev);

int devfreq_remove_devbw(struct device *dev);

#else

static inline int devfreq_add_devbw(struct device *dev)

{

	return 0;

}

static inline int devfreq_remove_devbw(struct device *dev)

{

	return 0;

}

#endif



#endif /* _DEVFREQ_DEVBW_H */