Subject: Re: [PATCH] QorIQ/TMU: add thermal management support based on TMU

From: Eduardo Valentin <[email-masked]>
Date: Mon, 11 May 2015 18:49:00 -0700

Jia Hongtao,

Thanks for sharing your driver. Sorry for the late answer. Please find
couple of comments as follows.

On Fri, Apr 03, 2015 at 03:11:27PM +0800, Jia Hongtao wrote:
> It supports one critical trip point and one passive trip point.
> The cpufreq is used as the cooling device to throttle CPUs when
> the passive trip is crossed.
> 
> Signed-off-by: Jia Hongtao <[email-masked]>
> ---
>  drivers/thermal/Kconfig         |  11 ++
>  drivers/thermal/Makefile        |   1 +
>  drivers/thermal/qoriq_thermal.c | 405 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 417 insertions(+)
>  create mode 100644 drivers/thermal/qoriq_thermal.c
> 
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index af40db0..c0a8bd1 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -147,6 +147,17 @@ config IMX_THERMAL
>  	  cpufreq is used as the cooling device to throttle CPUs when the
>  	  passive trip is crossed.
>  
> +config QORIQ_THERMAL
> +	tristate "Freescale QorIQ Thermal Monitoring Unit"
> +	depends on CPU_THERMAL
> +	depends on OF
> +	default n
> +	help
> +	  Enable thermal management based on Freescale QorIQ Thermal Monitoring
> +	  Unit (TMU). It supports one critical trip point and one passive trip
> +	  point. The cpufreq is used as the cooling device to throttle CPUs when
> +	  the passive trip is crossed.

dummy question, what is the level of overlap between QorIQ and IMX
thermal drivers?

> +
>  config SPEAR_THERMAL
>  	bool "SPEAr thermal sensor driver"
>  	depends on PLAT_SPEAR
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index fa0dc48..7de4847 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -31,6 +31,7 @@ obj-$(CONFIG_DOVE_THERMAL)  	+= dove_thermal.o
>  obj-$(CONFIG_DB8500_THERMAL)	+= db8500_thermal.o
>  obj-$(CONFIG_ARMADA_THERMAL)	+= armada_thermal.o
>  obj-$(CONFIG_IMX_THERMAL)	+= imx_thermal.o
> +obj-$(CONFIG_QORIQ_THERMAL)	+= qoriq_thermal.o
>  obj-$(CONFIG_DB8500_CPUFREQ_COOLING)	+= db8500_cpufreq_cooling.o
>  obj-$(CONFIG_INTEL_POWERCLAMP)	+= intel_powerclamp.o
>  obj-$(CONFIG_X86_PKG_TEMP_THERMAL)	+= x86_pkg_temp_thermal.o
> diff --git a/drivers/thermal/qoriq_thermal.c b/drivers/thermal/qoriq_thermal.c
> new file mode 100644
> index 0000000..f5d3a2c
> --- /dev/null
> +++ b/drivers/thermal/qoriq_thermal.c
> @@ -0,0 +1,405 @@
> +/*
> + * Copyright 2015 Freescale Semiconductor, Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + */
> +
> +/*
> + * Based on Freescale QorIQ Thermal Monitoring Unit (TMU)
> + */
> +#include <linux/cpufreq.h>
> +#include <linux/cpu_cooling.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/thermal.h>
> +
> +#define SITES_MAX		16
> +
> +#define TMU_TEMP_PASSIVE	85000
> +#define TMU_TEMP_CRITICAL	95000
> +
> +#define TMU_PASSIVE_DELAY	1000	/* Milliseconds */
> +#define TMU_POLLING_DELAY	5000
> +
> +/* The driver supports 1 passive trip point and 1 critical trip point */
> +enum tmu_thermal_trip {
> +	TMU_TRIP_PASSIVE,
> +	TMU_TRIP_CRITICAL,
> +	TMU_TRIP_NUM,
> +};
> +

the above symbol is not used in this driver.

> +/*
> + * QorIQ TMU Registers
> + */
> +struct qoriq_tmu_site_regs {
> +	__be32 tritsr;		/* Immediate Temperature Site Register */
> +	__be32 tratsr;		/* Average Temperature Site Register */
> +	u8 res0[0x8];
> +} __packed;
> +
> +struct qoriq_tmu_regs {
> +	__be32 tmr;		/* Mode Register */
> +#define TMR_DISABLE	0x0
> +#define TMR_ME		0x80000000
> +#define TMR_ALPF	0x0c000000
> +#define TMR_MSITE	0x00008000
> +#define TMR_ALL		(TMR_ME | TMR_ALPF | TMR_MSITE)
> +	__be32 tsr;		/* Status Register */
> +	__be32 tmtmir;		/* Temperature measurement interval Register */
> +#define TMTMIR_DEFAULT	0x00000007
> +	u8 res0[0x14];
> +	__be32 tier;		/* Interrupt Enable Register */
> +#define TIER_DISABLE	0x0
> +	__be32 tidr;		/* Interrupt Detect Register */
> +	__be32 tiscr;		/* Interrupt Site Capture Register */
> +	__be32 ticscr;		/* Interrupt Critical Site Capture Register */
> +	u8 res1[0x10];
> +	__be32 tmhtcrh;		/* High Temperature Capture Register */
> +	__be32 tmhtcrl;		/* Low Temperature Capture Register */
> +	u8 res2[0x8];
> +	__be32 tmhtitr;		/* High Temperature Immediate Threshold */
> +	__be32 tmhtatr;		/* High Temperature Average Threshold */
> +	__be32 tmhtactr;	/* High Temperature Average Crit Threshold */
> +	u8 res3[0x24];
> +	__be32 ttcfgr;		/* Temperature Configuration Register */
> +	__be32 tscfgr;		/* Sensor Configuration Register */
> +	u8 res4[0x78];
> +	struct qoriq_tmu_site_regs site[SITES_MAX];
> +	u8 res5[0x9f8];
> +	__be32 ipbrr0;		/* IP Block Revision Register 0 */
> +	__be32 ipbrr1;		/* IP Block Revision Register 1 */
> +	u8 res6[0x310];
> +	__be32 ttr0cr;		/* Temperature Range 0 Control Register */
> +	__be32 ttr1cr;		/* Temperature Range 1 Control Register */
> +	__be32 ttr2cr;		/* Temperature Range 2 Control Register */
> +	__be32 ttr3cr;		/* Temperature Range 3 Control Register */
> +};
> +
> +/*
> + * Thermal zone data
> + */
> +struct qoriq_tmu_data {
> +	struct thermal_zone_device *tz;
> +	struct thermal_cooling_device *cdev;
> +	enum thermal_device_mode mode;
> +	unsigned long temp_passive;
> +	unsigned long temp_critical;
> +	struct qoriq_tmu_regs __iomem *regs;
> +};
> +
> +static int tmu_get_mode(struct thermal_zone_device *tz,
> +			enum thermal_device_mode *mode)
> +{
> +	struct qoriq_tmu_data *data = tz->devdata;
> +
> +	*mode = data->mode;
> +
> +	return 0;
> +}
> +
> +static int tmu_set_mode(struct thermal_zone_device *tz,
> +			enum thermal_device_mode mode)
> +{
> +	struct qoriq_tmu_data *data = tz->devdata;
> +
> +	if (mode == THERMAL_DEVICE_ENABLED) {
> +		tz->polling_delay = TMU_POLLING_DELAY;
> +		tz->passive_delay = TMU_PASSIVE_DELAY;
> +		thermal_zone_device_update(tz);
> +	} else {
> +		tz->polling_delay = 0;
> +		tz->passive_delay = 0;
> +	}
> +
> +	data->mode = mode;
> +
> +	return 0;
> +}
> +
> +static int tmu_get_temp(struct thermal_zone_device *tz, unsigned long *temp)
> +{
> +	u8 val;
> +	struct qoriq_tmu_data *data = tz->devdata;
> +
> +	val = ioread32be(&data->regs->site[0].tritsr);
> +	*temp = (unsigned long)val * 1000;
> +
> +	return 0;
> +}
> +
> +static int tmu_get_trip_type(struct thermal_zone_device *tz, int trip,
> +			     enum thermal_trip_type *type)
> +{
> +	*type = (trip == TMU_TRIP_PASSIVE) ? THERMAL_TRIP_PASSIVE :
> +					     THERMAL_TRIP_CRITICAL;
> +	return 0;
> +}
> +
> +static int tmu_get_trip_temp(struct thermal_zone_device *tz, int trip,
> +			     unsigned long *temp)
> +{
> +	struct qoriq_tmu_data *data = tz->devdata;
> +
> +	*temp = (trip == TMU_TRIP_PASSIVE) ? data->temp_passive :
> +					     data->temp_critical;
> +	return 0;
> +}
> +
> +static int tmu_get_crit_temp(struct thermal_zone_device *tz,
> +			     unsigned long *temp)
> +{
> +	struct qoriq_tmu_data *data = tz->devdata;
> +
> +	*temp = data->temp_critical;

nip: add an empty line, to follow your pattern.

> +	return 0;
> +}
> +
> +static int tmu_get_trend(struct thermal_zone_device *thermal,
> +			int trip, enum thermal_trend *trend)
> +{
> +	int ret;
> +	unsigned long trip_temp;
> +
> +	ret = tmu_get_trip_temp(thermal, trip, &trip_temp);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (thermal->temperature >= trip_temp)
> +		*trend = THERMAL_TREND_RAISE_FULL;
> +	else
> +		*trend = THERMAL_TREND_DROP_FULL;
> +

Did I miss something here
or that is not really trending, is it? 

Trending is supposed to be 
delta(temperature)/delta(time).

> +	return 0;
> +}
> +
> +static int tmu_bind(struct thermal_zone_device *tz,
> +		    struct thermal_cooling_device *cdev)
> +{
> +	int ret;
> +
> +	ret = thermal_zone_bind_cooling_device(tz, TMU_TRIP_PASSIVE, cdev,
> +					       THERMAL_NO_LIMIT,
> +					       THERMAL_NO_LIMIT);
> +	if (ret) {
> +		dev_err(&tz->device,
> +			"Binding zone %s with cdev %s failed:%d\n",
> +			tz->type, cdev->type, ret);
> +		return ret;
> +	}

> +
> +	return 0;

I think it is fine if you just return ret;

> +}
> +
> +static int tmu_unbind(struct thermal_zone_device *tz,
> +		      struct thermal_cooling_device *cdev)
> +{
> +	int ret;
> +
> +	ret = thermal_zone_unbind_cooling_device(tz, TMU_TRIP_PASSIVE, cdev);
> +	if (ret) {
> +		dev_err(&tz->device,
> +			"Unbinding zone %s with cdev %s failed:%d\n",
> +			tz->type, cdev->type, ret);
> +		return ret;
> +	}

ditto.

> +
> +	return 0;
> +}
> +
> +static void qoriq_tmu_calibration(struct platform_device *pdev)
> +{
> +	int i, val, len;
> +	const __be32 *calibration;
> +	struct device_node *node = pdev->dev.of_node;
> +	struct qoriq_tmu_data *data = dev_get_drvdata(&pdev->dev);
> +
> +	/* Disable monitoring before calibration */
> +	iowrite32be(TMR_DISABLE, &data->regs->tmr);
> +
> +	calibration = of_get_property(node, "calibration", &len);
> +	if (calibration == NULL) {
> +		pr_err("TMU: Failed to get calibration data.\n");

use dev_err when possible.

> +		return;
> +	}
> +
> +	for (i = 0; i < len; i += 8, calibration += 2) {
> +		val = (int)of_read_number(calibration, 1);
> +		iowrite32be(val, &data->regs->ttcfgr);
> +		val = (int)of_read_number(calibration + 1, 1);
> +		iowrite32be(val, &data->regs->tscfgr);

are the above properties your offset and slope extrapolation constants?

If yes, please use the coefficients DT property. Please, check the of
thermal code.

> +	}
> +}
> +
> +static void qoriq_tmu_init_device(struct qoriq_tmu_data *data)
> +{
> +	/* Disable interrupt, using polling instead */
> +	iowrite32be(TIER_DISABLE, &data->regs->tier);
> +
> +	/* Set update_interval */
> +	iowrite32be(TMTMIR_DEFAULT, &data->regs->tmtmir);
> +
> +	/* Enable monitoring */
> +	iowrite32be(TMR_ALL, &data->regs->tmr);
> +}
> +
> +static struct thermal_zone_device_ops tmu_tz_ops = {
> +	.bind = tmu_bind,
> +	.unbind = tmu_unbind,
> +	.get_temp = tmu_get_temp,
> +	.get_trend = tmu_get_trend,
> +	.get_mode = tmu_get_mode,
> +	.set_mode = tmu_set_mode,
> +	.get_trip_type = tmu_get_trip_type,
> +	.get_trip_temp = tmu_get_trip_temp,
> +	.get_crit_temp = tmu_get_crit_temp,
> +};
> +
> +static int qoriq_tmu_probe(struct platform_device *pdev)
> +{
> +	int ret;
> +	struct cpumask clip_cpus;
> +	struct qoriq_tmu_data *data;
> +
> +	if (!cpufreq_get_current_driver()) {
> +		dev_dbg(&pdev->dev, "No cpufreq driver yet\n");
> +		return -EPROBE_DEFER;
> +	}
> +
> +	if (!pdev->dev.of_node) {
> +		dev_err(&pdev->dev, "Device OF-Node is NULL");
> +		return -EFAULT;
> +	}
> +
> +	data = devm_kzalloc(&pdev->dev, sizeof(struct qoriq_tmu_data),
> +			    GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	dev_set_drvdata(&pdev->dev, data);
> +	data->regs = of_iomap(pdev->dev.of_node, 0);
> +
> +	if (!data->regs) {
> +		dev_err(&pdev->dev, "Failed to get memory region\n");
> +		ret = -ENODEV;
> +		goto err_iomap;
> +	}
> +
> +	qoriq_tmu_calibration(pdev);	/* TMU calibration */
> +
> +	qoriq_tmu_init_device(data);	/* TMU initialization */
> +
> +	cpumask_setall(&clip_cpus);
> +	data->cdev = cpufreq_cooling_register(&clip_cpus);

Given that this is a DT based device driver, have you considered using
OF thermal APIs?

> +	if (IS_ERR(data->cdev)) {
> +		ret = PTR_ERR(data->cdev);
> +		dev_err(&data->cdev->device,
> +			"Failed to register cpufreq cooling device: %d\n", ret);
> +		goto err_cooling;
> +	}
> +
> +	data->temp_passive = TMU_TEMP_PASSIVE;
> +	data->temp_critical = TMU_TEMP_CRITICAL;
> +	data->tz = thermal_zone_device_register("tmu_thermal_zone",
> +						TMU_TRIP_NUM,
> +						0, data,
> +						&tmu_tz_ops, NULL,
> +						TMU_PASSIVE_DELAY,
> +						TMU_POLLING_DELAY);
> +
> +	if (IS_ERR(data->tz)) {
> +		ret = PTR_ERR(data->tz);
> +		dev_err(&pdev->dev,
> +			"Failed to register thermal zone device %d\n", ret);
> +		goto err_thermal;
> +	}
> +
> +	data->mode = THERMAL_DEVICE_ENABLED;

Don't you need to get a clock and enable it before handling this sensor?

> +
> +	return 0;
> +
> +err_thermal:
> +	cpufreq_cooling_unregister(data->cdev);
> +
> +err_cooling:
> +	iounmap(data->regs);
> +
> +err_iomap:
> +	dev_set_drvdata(&pdev->dev, NULL);
> +	devm_kfree(&pdev->dev, data);
> +
> +	return ret;
> +}
> +
> +static int qoriq_tmu_remove(struct platform_device *pdev)
> +{
> +	struct qoriq_tmu_data *data = dev_get_drvdata(&pdev->dev);
> +
> +	/* Disable monitoring */
> +	iowrite32be(TMR_DISABLE, &data->regs->tmr);
> +
> +	thermal_zone_device_unregister(data->tz);
> +	cpufreq_cooling_unregister(data->cdev);
> +	iounmap(data->regs);
> +
> +	dev_set_drvdata(&pdev->dev, NULL);
> +	devm_kfree(&pdev->dev, data);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int qoriq_tmu_suspend(struct device *dev)
> +{
> +	struct qoriq_tmu_data *data = dev_get_drvdata(dev);
> +
> +	/* Disable monitoring */
> +	iowrite32be(TMR_DISABLE, &data->regs->tmr);
> +
> +	return 0;
> +}
> +
> +static int qoriq_tmu_resume(struct device *dev)
> +{
> +	struct qoriq_tmu_data *data = dev_get_drvdata(dev);
> +
> +	/* Enable monitoring */
> +	iowrite32be(TMR_ALL, &data->regs->tmr);
> +
> +	return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(qoriq_tmu_pm_ops,
> +			 qoriq_tmu_suspend, qoriq_tmu_resume);
> +
> +static const struct of_device_id qoriq_tmu_match[] = {
> +	{ .compatible = "fsl,qoriq-tmu", },
> +	{},
> +};

You need to add a binding file describing your chip, and how
to deploy its DT nodes under:
 Documentation/devicetree/bindings/thermal/

> +
> +static struct platform_driver qoriq_tmu = {
> +	.driver	= {
> +		.owner		= THIS_MODULE,
> +		.name		= "qoriq_thermal",
> +		.pm = &qoriq_tmu_pm_ops,
> +		.of_match_table	= qoriq_tmu_match,
> +	},
> +	.probe	= qoriq_tmu_probe,
> +	.remove	= qoriq_tmu_remove,
> +};
> +module_platform_driver(qoriq_tmu);
> +
> +MODULE_AUTHOR("Jia Hongtao <[email-masked]>");
> +MODULE_DESCRIPTION("Freescale QorIQ Thermal Monitoring Unit driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.1.0.27.g96db324
> 
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