Subject: Re: [PATCH V3] thermal: qoriq: Add thermal management support

From: Scott Wood <[email-masked]>
Date: Thu, 24 Sep 2015 17:09:52 -0500

On Wed, 2015-09-23 at 16:28 +0800, Jia Hongtao wrote:
> This driver add thermal management support by enabling TMU (Thermal
> Monitoring Unit) on QorIQ platform.
> 
> It's based on thermal of framework:
> - Trip points defined in device tree.
> - Cpufreq as cooling device registered in qoriq cpufreq driver.

I don't see any cooling device registered in the qoriq cpufreq driver.  Is 
this dependent on some other patch?

> 
> Signed-off-by: Jia Hongtao <[email-masked]>
> ---
> V3: Using thermal of framework.
> 
>  drivers/thermal/Kconfig         |  11 ++
>  drivers/thermal/Makefile        |   1 +
>  drivers/thermal/qoriq_thermal.c | 267 
> ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 279 insertions(+)
>  create mode 100644 drivers/thermal/qoriq_thermal.c
> 
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 0390044..c91041b 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -180,6 +180,17 @@ 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 THERMAL_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.

"default n" is unnecessary -- n is already the default.

Where is the interaction between this driver and cpufreq?

> config SPEAR_THERMAL
>       bool "SPEAr thermal sensor driver"
>       depends on PLAT_SPEAR
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 26f1608..e55d703 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -33,6 +33,7 @@ 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..7c2a3261
> --- /dev/null
> +++ b/drivers/thermal/qoriq_thermal.c
> @@ -0,0 +1,267 @@
> +/*
> + * 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)
> + */

What does this comment mean?  This *is* the "Freescale QorIQ Thermal 
Monitoring Unit" driver.

> +#include <linux/cpufreq.h>

What do you use from this header?

> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/thermal.h>
> +
> +#include "thermal_core.h"
> +
> +#define SITES_MAX    16
> +
> +/*
> + * 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      /* Core temperature site */
> +#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 qoriq_tmu_regs __iomem *regs;
> +};
> +

> +static int tmu_get_temp(void *p, int *temp)
> +{
> +     u8 val;
> +     struct qoriq_tmu_data *data = p;
> +
> +     val = ioread32be(&data->regs->site[0].tritsr);
> +     *temp = (int)val * 1000;

Why don't you declare val as int in the first place?

> +     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);

Unnecessary casts.

> +     }
> +
> +     return 0;
> +}
> +
> +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_of_device_ops tmu_tz_ops = {
> +     .get_temp = tmu_get_temp,
> +};
> +
> +static int qoriq_tmu_probe(struct platform_device *pdev)
> +{
> +     int ret;
> +     const struct thermal_trip *trip;
> +     struct qoriq_tmu_data *data;
> +
> +     if (!pdev->dev.of_node) {
> +             dev_err(&pdev->dev, "Device OF-Node is NULL");
> +             return -EFAULT;
> +     }

EFAULT is for bad user addresses and is not appropriate here.

> +
> +     data = devm_kzalloc(&pdev->dev, sizeof(struct qoriq_tmu_data),
> +                         GFP_KERNEL);
> +     if (!data)
> +             return -ENOMEM;
> +
> +     platform_set_drvdata(pdev, 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;
> +     }
> +
> +     ret = qoriq_tmu_calibration(pdev);      /* TMU calibration */
> +     if (ret < 0) {
> +             dev_err(&pdev->dev, "TMU calibration failed.\n");
> +             ret = -ENODEV;
> +             goto err_iomap;
> +     }

That function returns negative when device tree properties are missing, not 
when a calibration procedure fails.

> +
> +     qoriq_tmu_init_device(data);    /* TMU initialization */
> +
> +     data->tz = thermal_zone_of_sensor_register(&pdev->dev, 0,
> +                             data, &tmu_tz_ops);
> +     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;
> +     }
> +
> +     trip = of_thermal_get_trip_points(data->tz);
> +
> +     data->tz->ops->set_mode(data->tz, THERMAL_DEVICE_ENABLED);

Doesn't thermal_zone_of_sensor_register() already call ops->set_mode with 
TERMAL_DEVICE_ENABLED?

> +
> +     return 0;
> +
> +err_thermal:
> +     iounmap(data->regs);
> +
> +err_iomap:
> +     platform_set_drvdata(pdev, NULL);
> +     devm_kfree(&pdev->dev, data);
> +
> +     return ret;
> +}
> +
> +static int qoriq_tmu_remove(struct platform_device *pdev)
> +{
> +     struct qoriq_tmu_data *data = platform_get_drvdata(pdev);
> +
> +     /* Disable monitoring */
> +     iowrite32be(TMR_DISABLE, &data->regs->tmr);
> +
> +     thermal_zone_of_sensor_unregister(&pdev->dev, data->tz);
> +     iounmap(data->regs);
> +
> +     platform_set_drvdata(pdev, 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);
> +     data->tz->ops->set_mode(data->tz, THERMAL_DEVICE_DISABLED);
> +
> +     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);
> +     data->tz->ops->set_mode(data->tz, THERMAL_DEVICE_ENABLED);
> +
> +     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", },
> +     {},
> +};

Binding?

> +
> +static struct platform_driver qoriq_tmu = {
> +     .driver = {
> +             .name           = "qoriq_thermal",
> +             .pm = &qoriq_tmu_pm_ops,
> +             .of_match_table = qoriq_tmu_match,
> +     },

Why the tabs after ".name"?

-Scott