[1/2] LoongArch: Add CPU HWMon platform driver

This add CPU HWMon (temperature sensor) platform driver for Loongson-3.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/platform/Kconfig               |   3 +
 drivers/platform/Makefile              |   1 +
 drivers/platform/loongarch/Kconfig     |  26 ++++
 drivers/platform/loongarch/Makefile    |   1 +
 drivers/platform/loongarch/cpu_hwmon.c | 195 +++++++++++++++++++++++++
 5 files changed, 226 insertions(+)
 create mode 100644 drivers/platform/loongarch/Kconfig
 create mode 100644 drivers/platform/loongarch/Makefile
 create mode 100644 drivers/platform/loongarch/cpu_hwmon.c

It shows my CPU temperature is floating between 48 and 50 Celsius. 
Higher than I expected but I guess it's because we've not implemented
CPUFreq yet.

Tested-by: Xi Ruoyao <xry111@xry111.site>

On Mon, 2022-08-15 at 20:48 +0800, Huacai Chen wrote:
> This add CPU HWMon (temperature sensor) platform driver for Loongson-
> 3.
> 
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
>  drivers/platform/Kconfig               |   3 +
>  drivers/platform/Makefile              |   1 +
>  drivers/platform/loongarch/Kconfig     |  26 ++++
>  drivers/platform/loongarch/Makefile    |   1 +
>  drivers/platform/loongarch/cpu_hwmon.c | 195
> +++++++++++++++++++++++++
>  5 files changed, 226 insertions(+)
>  create mode 100644 drivers/platform/loongarch/Kconfig
>  create mode 100644 drivers/platform/loongarch/Makefile
>  create mode 100644 drivers/platform/loongarch/cpu_hwmon.c
> 
> diff --git a/drivers/platform/Kconfig b/drivers/platform/Kconfig
> index b437847b6237..9c68e2def2cb 100644
> --- a/drivers/platform/Kconfig
> +++ b/drivers/platform/Kconfig
> @@ -2,6 +2,9 @@
>  if MIPS
>  source "drivers/platform/mips/Kconfig"
>  endif
> +if LOONGARCH
> +source "drivers/platform/loongarch/Kconfig"
> +endif
>  
>  source "drivers/platform/goldfish/Kconfig"
>  
> diff --git a/drivers/platform/Makefile b/drivers/platform/Makefile
> index 4de08ef4ec9d..41640172975a 100644
> --- a/drivers/platform/Makefile
> +++ b/drivers/platform/Makefile
> @@ -4,6 +4,7 @@
>  #
>  
>  obj-$(CONFIG_X86)              += x86/
> +obj-$(CONFIG_LOONGARCH)                += loongarch/
>  obj-$(CONFIG_MELLANOX_PLATFORM)        += mellanox/
>  obj-$(CONFIG_MIPS)             += mips/
>  obj-$(CONFIG_OLPC_EC)          += olpc/
> diff --git a/drivers/platform/loongarch/Kconfig
> b/drivers/platform/loongarch/Kconfig
> new file mode 100644
> index 000000000000..a1542843b0ad
> --- /dev/null
> +++ b/drivers/platform/loongarch/Kconfig
> @@ -0,0 +1,26 @@
> +#
> +# LoongArch Platform Specific Drivers
> +#
> +
> +menuconfig LOONGARCH_PLATFORM_DEVICES
> +       bool "LoongArch Platform Specific Device Drivers"
> +       default LOONGARCH
> +       help
> +         Say Y here to get to see options for device drivers of
> various
> +         LoongArch platforms, including vendor-specific
> laptop/desktop
> +         extension and hardware monitor drivers. This option itself
> does
> +         not add any kernel code.
> +
> +         If you say N, all options in this submenu will be skipped
> and disabled.
> +
> +if LOONGARCH_PLATFORM_DEVICES
> +
> +config CPU_HWMON
> +       bool "Loongson CPU HWMon Driver"
> +       depends on MACH_LOONGSON64
> +       select HWMON
> +       default y
> +       help
> +         Loongson-3A/3B/3C CPU HWMon (temperature sensor) driver.
> +
> +endif # LOONGARCH_PLATFORM_DEVICES
> diff --git a/drivers/platform/loongarch/Makefile
> b/drivers/platform/loongarch/Makefile
> new file mode 100644
> index 000000000000..8dfd03924c37
> --- /dev/null
> +++ b/drivers/platform/loongarch/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_CPU_HWMON) += cpu_hwmon.o
> diff --git a/drivers/platform/loongarch/cpu_hwmon.c
> b/drivers/platform/loongarch/cpu_hwmon.c
> new file mode 100644
> index 000000000000..3673c850f66c
> --- /dev/null
> +++ b/drivers/platform/loongarch/cpu_hwmon.c
> @@ -0,0 +1,195 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2022 Loongson Technology Corporation Limited
> + */
> +#include <linux/module.h>
> +#include <linux/reboot.h>
> +#include <linux/jiffies.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +
> +#include <asm/loongson.h>
> +
> +int loongson3_cpu_temp(int cpu)
> +{
> +       u32 reg;
> +
> +       reg = iocsr_read32(LOONGARCH_IOCSR_CPUTEMP) & 0xff;
> +
> +       return (int)((s8)reg) * 1000;
> +}
> +EXPORT_SYMBOL(loongson3_cpu_temp);
> +
> +static int nr_packages;
> +static struct device *cpu_hwmon_dev;
> +
> +static ssize_t cpu_temp_label(struct device *dev,
> +                       struct device_attribute *attr, char *buf)
> +{
> +       int id = (to_sensor_dev_attr(attr))->index - 1;
> +       return sprintf(buf, "CPU %d Temperature\n", id);
> +}
> +
> +static ssize_t get_cpu_temp(struct device *dev,
> +                       struct device_attribute *attr, char *buf)
> +{
> +       int id = (to_sensor_dev_attr(attr))->index - 1;
> +       int value = loongson3_cpu_temp(id);
> +       return sprintf(buf, "%d\n", value);
> +}
> +
> +static SENSOR_DEVICE_ATTR(temp1_input, 0444, get_cpu_temp, NULL, 1);
> +static SENSOR_DEVICE_ATTR(temp1_label, 0444, cpu_temp_label, NULL,
> 1);
> +static SENSOR_DEVICE_ATTR(temp2_input, 0444, get_cpu_temp, NULL, 2);
> +static SENSOR_DEVICE_ATTR(temp2_label, 0444, cpu_temp_label, NULL,
> 2);
> +static SENSOR_DEVICE_ATTR(temp3_input, 0444, get_cpu_temp, NULL, 3);
> +static SENSOR_DEVICE_ATTR(temp3_label, 0444, cpu_temp_label, NULL,
> 3);
> +static SENSOR_DEVICE_ATTR(temp4_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp4_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp5_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp5_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp6_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp6_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp7_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp7_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp8_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp8_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp9_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp9_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp10_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp10_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp11_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp11_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp12_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp12_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp13_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp13_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp14_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp14_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp15_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp15_label, 0444, cpu_temp_label, NULL,
> 4);
> +static SENSOR_DEVICE_ATTR(temp16_input, 0444, get_cpu_temp, NULL, 4);
> +static SENSOR_DEVICE_ATTR(temp16_label, 0444, cpu_temp_label, NULL,
> 4);
> +
> +static struct attribute *cpu_hwmon_attributes[] = {
> +       &sensor_dev_attr_temp1_input.dev_attr.attr,
> +       &sensor_dev_attr_temp1_label.dev_attr.attr,
> +       &sensor_dev_attr_temp2_input.dev_attr.attr,
> +       &sensor_dev_attr_temp2_label.dev_attr.attr,
> +       &sensor_dev_attr_temp3_input.dev_attr.attr,
> +       &sensor_dev_attr_temp3_label.dev_attr.attr,
> +       &sensor_dev_attr_temp4_input.dev_attr.attr,
> +       &sensor_dev_attr_temp4_label.dev_attr.attr,
> +       &sensor_dev_attr_temp5_input.dev_attr.attr,
> +       &sensor_dev_attr_temp5_label.dev_attr.attr,
> +       &sensor_dev_attr_temp6_input.dev_attr.attr,
> +       &sensor_dev_attr_temp6_label.dev_attr.attr,
> +       &sensor_dev_attr_temp7_input.dev_attr.attr,
> +       &sensor_dev_attr_temp7_label.dev_attr.attr,
> +       &sensor_dev_attr_temp8_input.dev_attr.attr,
> +       &sensor_dev_attr_temp8_label.dev_attr.attr,
> +       &sensor_dev_attr_temp9_input.dev_attr.attr,
> +       &sensor_dev_attr_temp9_label.dev_attr.attr,
> +       &sensor_dev_attr_temp10_input.dev_attr.attr,
> +       &sensor_dev_attr_temp10_label.dev_attr.attr,
> +       &sensor_dev_attr_temp11_input.dev_attr.attr,
> +       &sensor_dev_attr_temp11_label.dev_attr.attr,
> +       &sensor_dev_attr_temp12_input.dev_attr.attr,
> +       &sensor_dev_attr_temp12_label.dev_attr.attr,
> +       &sensor_dev_attr_temp13_input.dev_attr.attr,
> +       &sensor_dev_attr_temp13_label.dev_attr.attr,
> +       &sensor_dev_attr_temp14_input.dev_attr.attr,
> +       &sensor_dev_attr_temp14_label.dev_attr.attr,
> +       &sensor_dev_attr_temp15_input.dev_attr.attr,
> +       &sensor_dev_attr_temp15_label.dev_attr.attr,
> +       &sensor_dev_attr_temp16_input.dev_attr.attr,
> +       &sensor_dev_attr_temp16_label.dev_attr.attr,
> +       NULL
> +};
> +static umode_t cpu_hwmon_is_visible(struct kobject *kobj,
> +                                   struct attribute *attr, int i)
> +{
> +       int id = i / 2;
> +
> +       if (id < nr_packages)
> +               return attr->mode;
> +       return 0;
> +}
> +
> +static struct attribute_group cpu_hwmon_group = {
> +       .attrs = cpu_hwmon_attributes,
> +       .is_visible = cpu_hwmon_is_visible,
> +};
> +
> +static const struct attribute_group *cpu_hwmon_groups[] = {
> +       &cpu_hwmon_group,
> +       NULL
> +};
> +
> +static int cpu_initial_threshold = 72000;
> +static int cpu_thermal_threshold = 96000;
> +module_param(cpu_thermal_threshold, int, 0644);
> +MODULE_PARM_DESC(cpu_thermal_threshold, "cpu thermal threshold (96000
> (default))");
> +
> +static struct delayed_work thermal_work;
> +
> +static void do_thermal_timer(struct work_struct *work)
> +{
> +       int i, value, temp_max = 0;
> +
> +       for (i=0; i<nr_packages; i++) {
> +               value = loongson3_cpu_temp(i);
> +               if (value > temp_max)
> +                       temp_max = value;
> +       }
> +
> +       if (temp_max <= cpu_thermal_threshold)
> +               schedule_delayed_work(&thermal_work,
> msecs_to_jiffies(5000));
> +       else
> +               orderly_poweroff(true);
> +}
> +
> +static int __init loongson_hwmon_init(void)
> +{
> +       int i, value, temp_max = 0;
> +
> +       pr_info("Loongson Hwmon Enter...\n");
> +
> +       nr_packages = loongson_sysconf.nr_cpus /
> +               loongson_sysconf.cores_per_package;
> +
> +       cpu_hwmon_dev = hwmon_device_register_with_groups(NULL,
> "cpu_hwmon",
> +                                                         NULL,
> cpu_hwmon_groups);
> +       if (IS_ERR(cpu_hwmon_dev)) {
> +               pr_err("hwmon_device_register fail!\n");
> +               return PTR_ERR(cpu_hwmon_dev);
> +       }
> +
> +       for (i = 0; i < nr_packages; i++) {
> +               value = loongson3_cpu_temp(i);
> +               if (value > temp_max)
> +                       temp_max = value;
> +       }
> +
> +       pr_info("Initial CPU temperature is %d (highest).\n",
> temp_max);
> +       if (temp_max > cpu_initial_threshold)
> +               cpu_thermal_threshold += temp_max -
> cpu_initial_threshold;
> +
> +       INIT_DEFERRABLE_WORK(&thermal_work, do_thermal_timer);
> +       schedule_delayed_work(&thermal_work, msecs_to_jiffies(20000));
> +
> +       return 0;
> +}
> +
> +static void __exit loongson_hwmon_exit(void)
> +{
> +       cancel_delayed_work_sync(&thermal_work);
> +       hwmon_device_unregister(cpu_hwmon_dev);
> +}
> +
> +module_init(loongson_hwmon_init);
> +module_exit(loongson_hwmon_exit);
> +
> +MODULE_AUTHOR("Huacai Chen <chenhuacai@loongson.cn>");
> +MODULE_DESCRIPTION("Loongson CPU Hwmon driver");
> +MODULE_LICENSE("GPL");