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Commit 82b56c07 authored by Amir Vajid's avatar Amir Vajid
Browse files

PM / devfreq: Add support for memory latency QoS voting 



Add a devfreq device that has the ability to vote for a
QoS level to ensure better memory latency.

Change-Id: I33094b45ec250a58f244ecb1b7b8476df8791425
Signed-off-by: default avatarAmir Vajid <avajid@codeaurora.org>
parent 01e00127

drivers/devfreq/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -225,6 +225,19 @@ config QCOM_DEVFREQ_DEVBW 
	  agnostic interface to so that some of the devfreq governors can be

	  shared across SoCs.



config ARM_QCOM_DEVFREQ_QOSLAT

	bool "Qualcomm Technologies Inc. DEVFREQ QOSLAT device driver"

	depends on ARCH_QCOM

	select DEVFREQ_GOV_PERFORMANCE

	select DEVFREQ_GOV_POWERSAVE

	select DEVFREQ_GOV_USERSPACE

	default n

	help

	  Some Qualcomm Technologies, Inc. (QTI) chipsets have an

	  interface to vote for a memory latency QoS level. This

	  driver votes on this interface to request a particular

	  memory latency QoS level.



source "drivers/devfreq/event/Kconfig"



endif # PM_DEVFREQ

drivers/devfreq/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 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

obj-$(CONFIG_ARM_QCOM_DEVFREQ_QOSLAT)	+= devfreq_qcom_qoslat.o



# DEVFREQ Event Drivers

obj-$(CONFIG_PM_DEVFREQ_EVENT)		+= event/

drivers/devfreq/devfreq_qcom_qoslat.c

0 → 100644
+147 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

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

 */



#define pr_fmt(fmt) "devfreq-qcom-qoslat: " fmt



#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/io.h>

#include <linux/delay.h>

#include <linux/err.h>

#include <linux/errno.h>

#include <linux/platform_device.h>

#include <linux/devfreq.h>

#include <linux/pm_opp.h>

#include <linux/of.h>

#include <linux/mailbox_client.h>

#include <linux/mailbox/qmp.h>



struct qoslat_data {

	struct mbox_client		mbox_cl;

	struct mbox_chan		*mbox;

	struct devfreq			*df;

	struct devfreq_dev_profile	profile;

	unsigned int			qos_level;

};



#define MAX_MSG_LEN	96

static int update_qos_level(struct device *dev, struct qoslat_data *d)

{

	struct qmp_pkt pkt;

	char mbox_msg[MAX_MSG_LEN + 1] = {0};

	char *qos_msg = "off";

	int ret;



	if (d->qos_level)

		qos_msg = "on";



	snprintf(mbox_msg, MAX_MSG_LEN, "{class: ddr, perfmode: %s}", qos_msg);

	pkt.size = MAX_MSG_LEN;

	pkt.data = mbox_msg;



	ret = mbox_send_message(d->mbox, &pkt);

	if (ret < 0) {

		dev_err(dev, "Failed to send mbox message: %d\n", ret);

		return ret;

	}



	return 0;

}



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

{

	struct qoslat_data *d = dev_get_drvdata(dev);

	struct dev_pm_opp *opp;



	opp = devfreq_recommended_opp(dev, freq, flags);

	if (!IS_ERR(opp))

		dev_pm_opp_put(opp);

	else

		return PTR_ERR(opp);



	if (*freq == d->qos_level)

		return 0;



	d->qos_level = *freq;



	return update_qos_level(dev, d);

}



static int dev_get_cur_freq(struct device *dev, unsigned long *freq)

{

	struct qoslat_data *d = dev_get_drvdata(dev);



	*freq = d->qos_level;



	return 0;

}



static int devfreq_qcom_qoslat_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct qoslat_data *d;

	struct devfreq_dev_profile *p;

	const char *gov_name;

	int ret = 0;



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

	if (!d)

		return -ENOMEM;

	dev_set_drvdata(dev, d);



	if (!of_find_property(dev->of_node, "mboxes", NULL)) {

		dev_err(dev, "Couldn't find AOP mbox\n");

		return -EINVAL;

	}

	d->mbox_cl.dev = dev;

	d->mbox_cl.tx_block = true;

	d->mbox_cl.tx_tout = 1000;

	d->mbox_cl.knows_txdone = false;

	d->mbox = mbox_request_channel(&d->mbox_cl, 0);

	if (IS_ERR(d->mbox)) {

		ret = PTR_ERR(d->mbox);

		dev_err(dev, "Failed to get mailbox channel: %d\n", ret);

		return ret;

	}

	d->qos_level = 0;



	p = &d->profile;

	p->target = dev_target;

	p->get_cur_freq = dev_get_cur_freq;

	p->polling_ms = 10;



	ret = dev_pm_opp_of_add_table(dev);

	if (ret < 0)

		dev_err(dev, "Couldn't parse OPP table: %d\n", ret);



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

		gov_name = "powersave";



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

	if (IS_ERR(d->df)) {

		ret = PTR_ERR(d->df);

		dev_err(dev, "Failed to add devfreq device: %d\n", ret);

		return ret;

	}



	return 0;

}



static const struct of_device_id devfreq_qoslat_match_table[] = {

	{ .compatible = "qcom,devfreq-qoslat" },

	{}

};



static struct platform_driver devfreq_qcom_qoslat_driver = {

	.probe = devfreq_qcom_qoslat_probe,

	.driver = {

		.name		= "devfreq-qcom-qoslat",

		.of_match_table = devfreq_qoslat_match_table,

	},

};

module_platform_driver(devfreq_qcom_qoslat_driver);

MODULE_DESCRIPTION("Device driver for setting memory latency qos level");

MODULE_LICENSE("GPL v2");