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Subject: Re: [v4 09/11] drivers/hwmon: Add PECI cputemp driver
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Jean Delvare <jdelvare@suse.com>,
        Jason M Biils <jason.m.bills@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org,
        Alan Cox <alan@linux.intel.com>,
        Andrew Jeffery <andrew@aj.id.au>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Arnd Bergmann <arnd@arndb.de>, Joel Stanley <joel@jms.id.au>,
        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Stef van Os <stef.van.os@prodrive-technologies.com>
References: <20180521195952.28073-1-jae.hyun.yoo@linux.intel.com>
 <20180521204238.GA26471@roeck-us.net>
 <f8824489-a0d7-6a13-baab-a6fc50164b67@linux.intel.com>
 <20180521210423.GB26644@roeck-us.net>
From:   Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Message-ID: <f1917418-43a3-22b2-7ba4-2a946611bcbc@linux.intel.com>
Date:   Mon, 21 May 2018 14:24:56 -0700
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On 5/21/2018 2:04 PM, Guenter Roeck wrote:
> On Mon, May 21, 2018 at 01:50:34PM -0700, Jae Hyun Yoo wrote:
>> On 5/21/2018 1:42 PM, Guenter Roeck wrote:
>>> On Mon, May 21, 2018 at 12:59:52PM -0700, Jae Hyun Yoo wrote:
>>>> This commit adds PECI cputemp hwmon driver.
>>>>
>>>> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
>>>> Reviewed-by: Haiyue Wang <haiyue.wang@linux.intel.com>
>>>> Reviewed-by: James Feist <james.feist@linux.intel.com>
>>>> Reviewed-by: Vernon Mauery <vernon.mauery@linux.intel.com>
>>>> Cc: Alan Cox <alan@linux.intel.com>
>>>> Cc: Andrew Jeffery <andrew@aj.id.au>
>>>> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>>>> Cc: Arnd Bergmann <arnd@arndb.de>
>>>> Cc: Jason M Biils <jason.m.bills@linux.intel.com>
>>>> Cc: Joel Stanley <joel@jms.id.au>
>>>> Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
>>>> Cc: Andrew Lunn <andrew@lunn.ch>
>>>> Cc: Stef van Os <stef.van.os@prodrive-technologies.com>
>>>> ---
>>>>   drivers/hwmon/Kconfig        |  14 ++
>>>>   drivers/hwmon/Makefile       |   1 +
>>>>   drivers/hwmon/peci-cputemp.c | 407 +++++++++++++++++++++++++++++++++++
>>>>   drivers/hwmon/peci-hwmon.c   | 124 +++++++++++
>>>>   drivers/hwmon/peci-hwmon.h   |  51 +++++
>>>>   5 files changed, 597 insertions(+)
>>>>   create mode 100644 drivers/hwmon/peci-cputemp.c
>>>>   create mode 100644 drivers/hwmon/peci-hwmon.c
>>>>   create mode 100644 drivers/hwmon/peci-hwmon.h
>>>>
>>>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
>>>> index f10840ad465c..8492586bb1e4 100644
>>>> --- a/drivers/hwmon/Kconfig
>>>> +++ b/drivers/hwmon/Kconfig
>>>> @@ -1256,6 +1256,20 @@ config SENSORS_NCT7904
>>>>   	  This driver can also be built as a module.  If so, the module
>>>>   	  will be called nct7904.
>>>> +config SENSORS_PECI_CPUTEMP
>>>> +	tristate "PECI CPU temperature monitoring support"
>>>> +	depends on OF
>>>> +	depends on PECI
>>>> +	help
>>>> +	  If you say yes here you get support for the generic Intel PECI
>>>> +	  cputemp driver which provides Digital Thermal Sensor (DTS) thermal
>>>> +	  readings of the CPU package and CPU cores that are accessible using
>>>> +	  the PECI Client Command Suite via the processor PECI client.
>>>> +	  Check Documentation/hwmon/peci-cputemp for details.
>>>> +
>>>> +	  This driver can also be built as a module.  If so, the module
>>>> +	  will be called peci-cputemp.
>>>> +
>>>>   config SENSORS_NSA320
>>>>   	tristate "ZyXEL NSA320 and compatible fan speed and temperature sensors"
>>>>   	depends on GPIOLIB && OF
>>>> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
>>>> index e7d52a36e6c4..d18b374a9000 100644
>>>> --- a/drivers/hwmon/Makefile
>>>> +++ b/drivers/hwmon/Makefile
>>>> @@ -136,6 +136,7 @@ obj-$(CONFIG_SENSORS_NCT7802)	+= nct7802.o
>>>>   obj-$(CONFIG_SENSORS_NCT7904)	+= nct7904.o
>>>>   obj-$(CONFIG_SENSORS_NSA320)	+= nsa320-hwmon.o
>>>>   obj-$(CONFIG_SENSORS_NTC_THERMISTOR)	+= ntc_thermistor.o
>>>> +obj-$(CONFIG_SENSORS_PECI_CPUTEMP)	+= peci-cputemp.o peci-hwmon.o
>>>>   obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
>>>>   obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
>>>>   obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
>>>> diff --git a/drivers/hwmon/peci-cputemp.c b/drivers/hwmon/peci-cputemp.c
>>>> new file mode 100644
>>>> index 000000000000..49c5a862bb58
>>>> --- /dev/null
>>>> +++ b/drivers/hwmon/peci-cputemp.c
>>>> @@ -0,0 +1,407 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +// Copyright (c) 2018 Intel Corporation
>>>> +
>>>> +#include <linux/hwmon.h>
>>>> +#include <linux/jiffies.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/of_device.h>
>>>> +
>>>> +#include "peci-hwmon.h"
>>>> +
>>>> +#define DEFAULT_CHANNEL_NUMS   4
>>>> +#define CORETEMP_CHANNEL_NUMS  CORE_NUMS_MAX
>>>> +#define CPUTEMP_CHANNEL_NUMS   (DEFAULT_CHANNEL_NUMS + CORETEMP_CHANNEL_NUMS)
>>>> +
>>>> +/* The RESOLVED_CORES register in PCU of a client CPU */
>>>> +#define REG_RESOLVED_CORES_BUS      1
>>>> +#define REG_RESOLVED_CORES_DEVICE   30
>>>> +#define REG_RESOLVED_CORES_FUNCTION 3
>>>> +#define REG_RESOLVED_CORES_OFFSET   0xB4
>>>> +
>>>> +struct temp_group {
>>>> +	struct temp_data die;
>>>> +	struct temp_data tcontrol;
>>>> +	struct temp_data tthrottle;
>>>> +	struct temp_data tjmax;
>>>> +	struct temp_data core[CORETEMP_CHANNEL_NUMS];
>>>> +};
>>>> +
>>>> +struct peci_cputemp {
>>>> +	struct peci_client *client;
>>>> +	struct device *dev;
>>>> +	char name[PECI_NAME_SIZE];
>>>> +	struct temp_group temp;
>>>> +	u8 addr;
>>>> +	uint cpu_no;
>>>> +	const struct cpu_gen_info *gen_info;
>>>> +	u32 core_mask;
>>>> +	u32 temp_config[CPUTEMP_CHANNEL_NUMS + 1];
>>>> +	uint config_idx;
>>>> +	struct hwmon_channel_info temp_info;
>>>> +	const struct hwmon_channel_info *info[2];
>>>> +	struct hwmon_chip_info chip;
>>>> +};
>>>> +
>>>> +enum cputemp_channels {
>>>> +	channel_die,
>>>> +	channel_tcontrol,
>>>> +	channel_tthrottle,
>>>> +	channel_tjmax,
>>>> +	channel_core,
>>>> +};
>>>> +
>>>> +static const u32 config_table[DEFAULT_CHANNEL_NUMS + 1] = {
>>>> +	/* Die temperature */
>>>> +	HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
>>>> +	HWMON_T_CRIT_HYST,
>>>> +
>>>> +	/* Tcontrol temperature */
>>>> +	HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_CRIT,
>>>> +
>>>> +	/* Tthrottle temperature */
>>>> +	HWMON_T_LABEL | HWMON_T_INPUT,
>>>> +
>>>> +	/* Tjmax temperature */
>>>> +	HWMON_T_LABEL | HWMON_T_INPUT,
>>>> +
>>>> +	/* Core temperature - for all core channels */
>>>> +	HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
>>>> +	HWMON_T_CRIT_HYST,
>>>> +};
>>>> +
>>>> +static const char *cputemp_label[CPUTEMP_CHANNEL_NUMS] = {
>>>> +	"Die",
>>>> +	"Tcontrol",
>>>> +	"Tthrottle",
>>>> +	"Tjmax",
>>>> +	"Core 0", "Core 1", "Core 2", "Core 3",
>>>> +	"Core 4", "Core 5", "Core 6", "Core 7",
>>>> +	"Core 8", "Core 9", "Core 10", "Core 11",
>>>> +	"Core 12", "Core 13", "Core 14", "Core 15",
>>>> +	"Core 16", "Core 17", "Core 18", "Core 19",
>>>> +	"Core 20", "Core 21", "Core 22", "Core 23",
>>>> +};
>>>> +
>>>> +static s32 ten_dot_six_to_millidegree(s32 val)
>>>> +{
>>>> +	return ((val ^ 0x8000) - 0x8000) * 1000 / 64;
>>>> +}
>>>> +
>>>> +static int get_temp_targets(struct peci_cputemp *priv)
>>>> +{
>>>> +	s32 tthrottle_offset;
>>>> +	s32 tcontrol_margin;
>>>> +	u8  pkg_cfg[4];
>>>> +	int rc;
>>>> +
>>>> +	/**
>>>> +	 * Just use only the tcontrol marker to determine if target values need
>>>> +	 * update.
>>>> +	 */
>>>> +	if (!peci_hwmon_need_update(&priv->temp.tcontrol))
>>>> +		return 0;
>>>> +
>>>> +	rc = peci_hwmon_rd_pkg_cfg_cmd(priv->client->adapter, priv->addr,
>>>> +				       MBX_INDEX_TEMP_TARGET, 0, pkg_cfg);
>>>> +	if (rc)
>>>> +		return rc;
>>>> +
>>>> +	priv->temp.tjmax.value = pkg_cfg[2] * 1000;
>>>> +
>>>> +	tcontrol_margin = pkg_cfg[1];
>>>> +	tcontrol_margin = ((tcontrol_margin ^ 0x80) - 0x80) * 1000;
>>>> +	priv->temp.tcontrol.value = priv->temp.tjmax.value - tcontrol_margin;
>>>> +
>>>> +	tthrottle_offset = (pkg_cfg[3] & 0x2f) * 1000;
>>>> +	priv->temp.tthrottle.value = priv->temp.tjmax.value - tthrottle_offset;
>>>> +
>>>> +	peci_hwmon_mark_updated(&priv->temp.tcontrol);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int get_die_temp(struct peci_cputemp *priv)
>>>> +{
>>>> +	struct peci_get_temp_msg msg;
>>>> +	int rc;
>>>> +
>>>> +	if (!peci_hwmon_need_update(&priv->temp.die))
>>>> +		return 0;
>>>> +
>>>> +	msg.addr = priv->addr;
>>>> +
>>>> +	rc = peci_command(priv->client->adapter, PECI_CMD_GET_TEMP, &msg);
>>>> +	if (rc)
>>>> +		return rc;
>>>> +
>>>> +	/* Note that the tjmax should be available before calling it */
>>>> +	priv->temp.die.value = priv->temp.tjmax.value +
>>>> +			       (msg.temp_raw * 1000 / 64);
>>>> +
>>>> +	peci_hwmon_mark_updated(&priv->temp.die);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int get_core_temp(struct peci_cputemp *priv, int core_index)
>>>> +{
>>>> +	s32 core_dts_margin;
>>>> +	u8  pkg_cfg[4];
>>>> +	int rc;
>>>> +
>>>> +	if (!peci_hwmon_need_update(&priv->temp.core[core_index]))
>>>> +		return 0;
>>>> +
>>>> +	rc = peci_hwmon_rd_pkg_cfg_cmd(priv->client->adapter, priv->addr,
>>>> +				       MBX_INDEX_PER_CORE_DTS_TEMP,
>>>> +				       core_index, pkg_cfg);
>>>> +	if (rc)
>>>> +		return rc;
>>>> +
>>>> +	core_dts_margin = le16_to_cpup((__le16 *)pkg_cfg);
>>>> +
>>>> +	/**
>>>> +	 * Processors return a value of the core DTS reading in 10.6 format
>>>> +	 * (10 bits signed decimal, 6 bits fractional).
>>>> +	 * Error codes:
>>>> +	 *   0x8000: General sensor error
>>>> +	 *   0x8001: Reserved
>>>> +	 *   0x8002: Underflow on reading value
>>>> +	 *   0x8003-0x81ff: Reserved
>>>> +	 */
>>>> +	if (core_dts_margin >= 0x8000 && core_dts_margin <= 0x81ff)
>>>> +		return -EIO;
>>>> +
>>>> +	core_dts_margin = ten_dot_six_to_millidegree(core_dts_margin);
>>>> +
>>>> +	/* Note that the tjmax should be available before calling it */
>>>> +	priv->temp.core[core_index].value = priv->temp.tjmax.value +
>>>> +					    core_dts_margin;
>>>> +
>>>> +	peci_hwmon_mark_updated(&priv->temp.core[core_index]);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int cputemp_read_string(struct device *dev,
>>>> +			       enum hwmon_sensor_types type,
>>>> +			       u32 attr, int channel, const char **str)
>>>> +{
>>>> +	if (attr != hwmon_temp_label)
>>>> +		return -EOPNOTSUPP;
>>>> +
>>>> +	*str = cputemp_label[channel];
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int cputemp_read(struct device *dev,
>>>> +			enum hwmon_sensor_types type,
>>>> +			u32 attr, int channel, long *val)
>>>> +{
>>>> +	struct peci_cputemp *priv = dev_get_drvdata(dev);
>>>> +	int rc, core_index;
>>>> +
>>>> +	if (channel >= CPUTEMP_CHANNEL_NUMS ||
>>>> +	    !(priv->temp_config[channel] & BIT(attr)))
>>>> +		return -EOPNOTSUPP;
>>>> +
>>>> +	rc = get_temp_targets(priv);
>>>> +	if (rc)
>>>> +		return rc;
>>>> +
>>>> +	switch (attr) {
>>>> +	case hwmon_temp_input:
>>>> +		switch (channel) {
>>>> +		case channel_die:
>>>> +			rc = get_die_temp(priv);
>>>> +			if (rc)
>>>> +				break;
>>>> +
>>>> +			*val = priv->temp.die.value;
>>>> +			break;
>>>> +		case channel_tcontrol:
>>>> +			*val = priv->temp.tcontrol.value;
>>>> +			break;
>>>> +		case channel_tthrottle:
>>>> +			*val = priv->temp.tthrottle.value;
>>>> +			break;
>>>> +		case channel_tjmax:
>>>> +			*val = priv->temp.tjmax.value;
>>>> +			break;
>>>> +		default:
>>>> +			core_index = channel - DEFAULT_CHANNEL_NUMS;
>>>> +			rc = get_core_temp(priv, core_index);
>>>> +			if (rc)
>>>> +				break;
>>>> +
>>>> +			*val = priv->temp.core[core_index].value;
>>>> +			break;
>>>> +		}
>>>> +		break;
>>>> +	case hwmon_temp_max:
>>>> +		*val = priv->temp.tcontrol.value;
>>>> +		break;
>>>> +	case hwmon_temp_crit:
>>>> +		*val = priv->temp.tjmax.value;
>>>> +		break;
>>>> +	case hwmon_temp_crit_hyst:
>>>> +		*val = priv->temp.tjmax.value - priv->temp.tcontrol.value;
>>>> +		break;
>>>> +	default:
>>>> +		rc = -EOPNOTSUPP;
>>>> +		break;
>>>> +	}
>>>> +
>>>> +	return rc;
>>>> +}
>>>> +
>>>> +static umode_t cputemp_is_visible(const void *data,
>>>> +				  enum hwmon_sensor_types type,
>>>> +				  u32 attr, int channel)
>>>> +{
>>>> +	const struct peci_cputemp *priv = data;
>>>> +
>>>> +	if (priv->temp_config[channel] & BIT(attr))
>>>> +		if (channel < DEFAULT_CHANNEL_NUMS ||
>>>> +		    (channel >= DEFAULT_CHANNEL_NUMS &&
>>>> +		     (priv->core_mask & BIT(channel - DEFAULT_CHANNEL_NUMS))))
>>>> +			return 0444;
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static const struct hwmon_ops cputemp_ops = {
>>>> +	.is_visible = cputemp_is_visible,
>>>> +	.read_string = cputemp_read_string,
>>>> +	.read = cputemp_read,
>>>> +};
>>>> +
>>>> +static int check_resolved_cores(struct peci_cputemp *priv)
>>>> +{
>>>> +	struct peci_rd_pci_cfg_local_msg msg;
>>>> +	int rc;
>>>> +
>>>> +	/* Get the RESOLVED_CORES register value */
>>>> +	msg.addr = priv->addr;
>>>> +	msg.bus = REG_RESOLVED_CORES_BUS;
>>>> +	msg.device = REG_RESOLVED_CORES_DEVICE;
>>>> +	msg.function = REG_RESOLVED_CORES_FUNCTION;
>>>> +	msg.reg = REG_RESOLVED_CORES_OFFSET;
>>>> +	msg.rx_len = 4;
>>>> +
>>>> +	rc = peci_command(priv->client->adapter, PECI_CMD_RD_PCI_CFG_LOCAL,
>>>> +			  &msg);
>>>> +	if (rc)
>>>> +		return rc;
>>>> +
>>>> +	priv->core_mask = le32_to_cpup((__le32 *)msg.pci_config);
>>>> +	if (!priv->core_mask)
>>>> +		return -EAGAIN;
>>>> +
>>>> +	dev_dbg(priv->dev, "Scanned resolved cores: 0x%x\n", priv->core_mask);
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int create_core_temp_info(struct peci_cputemp *priv)
>>>> +{
>>>> +	int rc, i;
>>>> +
>>>> +	rc = check_resolved_cores(priv);
>>>> +	if (rc)
>>>> +		return rc;
>>>> +
>>>> +	for (i = 0; i < priv->gen_info->core_max; i++)
>>>> +		if (priv->core_mask & BIT(i))
>>>> +			while (i + DEFAULT_CHANNEL_NUMS >= priv->config_idx)
>>>> +				priv->temp_config[priv->config_idx++] =
>>>> +					config_table[channel_core];
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int peci_cputemp_probe(struct peci_client *client)
>>>> +{
>>>> +	struct device *dev = &client->dev;
>>>> +	struct peci_cputemp *priv;
>>>> +	struct device *hwmon_dev;
>>>> +	int rc;
>>>> +
>>>> +	if ((client->adapter->cmd_mask &
>>>> +	    (BIT(PECI_CMD_GET_TEMP) | BIT(PECI_CMD_RD_PKG_CFG))) !=
>>>> +	    (BIT(PECI_CMD_GET_TEMP) | BIT(PECI_CMD_RD_PKG_CFG)))
>>>> +		return -ENODEV;
>>>> +
>>>> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>>>> +	if (!priv)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	dev_set_drvdata(dev, priv);
>>>> +	priv->client = client;
>>>> +	priv->dev = dev;
>>>> +	priv->addr = client->addr;
>>>> +	priv->cpu_no = priv->addr - PECI_BASE_ADDR;
>>>> +
>>>> +	snprintf(priv->name, PECI_NAME_SIZE, "peci_cputemp.cpu%d",
>>>> +		 priv->cpu_no);
>>>> +
>>>> +	rc = peci_hwmon_get_cpu_gen_info(client->adapter, priv->addr,
>>>> +					 &priv->gen_info);
>>>> +	if (rc)
>>>> +		return rc;
>>>> +
>>>> +	priv->temp_config[priv->config_idx++] = config_table[channel_die];
>>>> +	priv->temp_config[priv->config_idx++] = config_table[channel_tcontrol];
>>>> +	priv->temp_config[priv->config_idx++] = config_table[channel_tthrottle];
>>>> +	priv->temp_config[priv->config_idx++] = config_table[channel_tjmax];
>>>> +
>>>> +	rc = create_core_temp_info(priv);
>>>> +	if (rc)
>>>> +		dev_dbg(dev, "Skipped creating core temp info\n");
>>>> +
>>>> +	priv->chip.ops = &cputemp_ops;
>>>> +	priv->chip.info = priv->info;
>>>> +
>>>> +	priv->info[0] = &priv->temp_info;
>>>> +
>>>> +	priv->temp_info.type = hwmon_temp;
>>>> +	priv->temp_info.config = priv->temp_config;
>>>> +
>>>> +	hwmon_dev = devm_hwmon_device_register_with_info(priv->dev,
>>>> +							 priv->name,
>>>> +							 priv,
>>>> +							 &priv->chip,
>>>> +							 NULL);
>>>> +
>>>> +	if (IS_ERR(hwmon_dev))
>>>> +		return PTR_ERR(hwmon_dev);
>>>> +
>>>> +	dev_dbg(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), priv->name);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static const struct of_device_id peci_cputemp_of_table[] = {
>>>> +	{ .compatible = "intel,peci-cputemp" },
>>>> +	{ }
>>>> +};
>>>> +MODULE_DEVICE_TABLE(of, peci_cputemp_of_table);
>>>> +
>>>> +static const struct peci_device_id peci_cputemp_ids[] = {
>>>> +	{ "peci-cputemp", 0, },
>>>> +	{ }
>>>> +};
>>>> +MODULE_DEVICE_TABLE(peci, peci_cputemp_ids);
>>>> +
>>>> +static struct peci_driver peci_cputemp_driver = {
>>>> +	.probe    = peci_cputemp_probe,
>>>> +	.id_table = peci_cputemp_ids,
>>>> +	.driver   = {
>>>> +			.name           = "peci-cputemp",
>>>> +			.of_match_table = of_match_ptr(peci_cputemp_of_table),
>>>> +	},
>>>> +};
>>>> +module_peci_driver(peci_cputemp_driver);
>>>> +
>>>> +MODULE_AUTHOR("Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>");
>>>> +MODULE_DESCRIPTION("PECI cputemp driver");
>>>> +MODULE_LICENSE("GPL v2");
>>>> diff --git a/drivers/hwmon/peci-hwmon.c b/drivers/hwmon/peci-hwmon.c
>>>> new file mode 100644
>>>> index 000000000000..e137e301eb97
>>>> --- /dev/null
>>>> +++ b/drivers/hwmon/peci-hwmon.c
>>>> @@ -0,0 +1,124 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +// Copyright (c) 2018 Intel Corporation
>>>> +
>>>> +#include <linux/bitfield.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/peci.h>
>>>> +
>>>> +#include "peci-hwmon.h"
>>>> +
>>>> +#if IS_ENABLED(CONFIG_X86)
>>>> +#include <asm/intel-family.h>
>>>> +#else
>>>> +#define INTEL_FAM6_HASWELL_X   0x3F
>>>> +#define INTEL_FAM6_BROADWELL_X 0x4F
>>>> +#define INTEL_FAM6_SKYLAKE_X   0x55
>>>> +#endif
>>>
>>> The entire code is very Intel specific. Why this #if instead of
>>> making the driver dependent on X86 ?
>>>
>>
>> This code will be running on ARM kernel at this moment with a purpose
>> of monitoring remote x86 CPUs through PECI connection, so it's limited
>> on x86 build environment.
>>
> Then add that comment into the code to explain why you can not include
> asm/intel-family.h, and declare the defines unconditionally here.
> 
> The distinction is that the driver only _supports_ Intel CPUs but
> can _run_ in the kernel of other architectures. This should be explained.
> 
> Thanks,
> Guenter
> 

Got it. I'll add a comment to explain that. Thanks a lot again!

-Jae

>>>> +
>>>> +#define LOWER_NIBBLE_MASK      GENMASK(3, 0)
>>>> +#define UPPER_NIBBLE_MASK      GENMASK(7, 4)
>>>> +
>>>> +#define CPU_ID_MODEL_MASK      GENMASK(7, 4)
>>>> +#define CPU_ID_FAMILY_MASK     GENMASK(11, 8)
>>>> +#define CPU_ID_EXT_MODEL_MASK  GENMASK(19, 16)
>>>> +#define CPU_ID_EXT_FAMILY_MASK GENMASK(27, 20)
>>>> +
>>>> +enum cpu_gens {
>>>> +	CPU_GEN_HSX = 0, /* Haswell Xeon */
>>>> +	CPU_GEN_BRX,     /* Broadwell Xeon */
>>>> +	CPU_GEN_SKX,     /* Skylake Xeon */
>>>> +};
>>>> +
>>>> +static const struct cpu_gen_info cpu_gen_info_table[] = {
>>>> +	[CPU_GEN_HSX] = {
>>>> +		.family        = 6, /* Family code */
>>>> +		.model         = INTEL_FAM6_HASWELL_X,
>>>> +		.core_max      = CORE_MAX_ON_HSX,
>>>> +		.chan_rank_max = CHAN_RANK_MAX_ON_HSX,
>>>> +		.dimm_idx_max  = DIMM_IDX_MAX_ON_HSX },
>>>> +	[CPU_GEN_BRX] = {
>>>> +		.family        = 6, /* Family code */
>>>> +		.model         = INTEL_FAM6_BROADWELL_X,
>>>> +		.core_max      = CORE_MAX_ON_BDX,
>>>> +		.chan_rank_max = CHAN_RANK_MAX_ON_BDX,
>>>> +		.dimm_idx_max  = DIMM_IDX_MAX_ON_BDX },
>>>> +	[CPU_GEN_SKX] = {
>>>> +		.family        = 6, /* Family code */
>>>> +		.model         = INTEL_FAM6_SKYLAKE_X,
>>>> +		.core_max      = CORE_MAX_ON_SKX,
>>>> +		.chan_rank_max = CHAN_RANK_MAX_ON_SKX,
>>>> +		.dimm_idx_max  = DIMM_IDX_MAX_ON_SKX },
>>>> +};
>>>> +
>>>> +int peci_hwmon_get_cpu_gen_info(struct peci_adapter *adapter, u8 addr,
>>>> +				const struct cpu_gen_info **gen_info)
>>>> +{
>>>> +	u32 cpu_id;
>>>> +	int i, rc;
>>>> +
>>>> +	rc = peci_get_cpu_id(adapter, addr, &cpu_id);
>>>> +	if (rc)
>>>> +		return rc;
>>>> +
>>>> +	for (i = 0; i < ARRAY_SIZE(cpu_gen_info_table); i++) {
>>>> +		if (FIELD_GET(CPU_ID_FAMILY_MASK, cpu_id) +
>>>> +			FIELD_GET(CPU_ID_EXT_FAMILY_MASK, cpu_id) ==
>>>> +				cpu_gen_info_table[i].family &&
>>>> +		    FIELD_GET(CPU_ID_MODEL_MASK, cpu_id) ==
>>>> +			FIELD_GET(LOWER_NIBBLE_MASK,
>>>> +				  cpu_gen_info_table[i].model) &&
>>>> +		    FIELD_GET(CPU_ID_EXT_MODEL_MASK, cpu_id) ==
>>>> +			FIELD_GET(UPPER_NIBBLE_MASK,
>>>> +				  cpu_gen_info_table[i].model)) {
>>>> +			break;
>>>> +		}
>>>> +	}
>>>> +
>>>> +	if (i >= ARRAY_SIZE(cpu_gen_info_table))
>>>> +		return -ENODEV;
>>>> +
>>>> +	*gen_info = &cpu_gen_info_table[i];
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(peci_hwmon_get_cpu_gen_info);
>>>> +
>>>> +bool peci_hwmon_need_update(struct temp_data *temp)
>>>> +{
>>>> +	if (temp->valid &&
>>>> +	    time_before(jiffies, temp->last_updated + UPDATE_INTERVAL))
>>>> +		return false;
>>>> +
>>>> +	return true;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(peci_hwmon_need_update);
>>>> +
>>>> +void peci_hwmon_mark_updated(struct temp_data *temp)
>>>> +{
>>>> +	temp->valid = 1;
>>>> +	temp->last_updated = jiffies;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(peci_hwmon_mark_updated);
>>>> +
>>>> +int peci_hwmon_rd_pkg_cfg_cmd(struct peci_adapter *adapter, u8 addr,
>>>> +			      u8 mbx_idx, u16 param, u8 *data)
>>>> +{
>>>> +	struct peci_rd_pkg_cfg_msg msg;
>>>> +	int rc;
>>>> +
>>>> +	msg.addr = addr;
>>>> +	msg.index = mbx_idx;
>>>> +	msg.param = param;
>>>> +	msg.rx_len = 4;
>>>> +
>>>> +	rc = peci_command(adapter, PECI_CMD_RD_PKG_CFG, &msg);
>>>> +	if (!rc)
>>>> +		memcpy(data, msg.pkg_config, 4);
>>>> +
>>>> +	return rc;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(peci_hwmon_rd_pkg_cfg_cmd);
>>>> +
>>>> +MODULE_AUTHOR("Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>");
>>>> +MODULE_DESCRIPTION("PECI hwmon module");
>>>> +MODULE_LICENSE("GPL v2");
>>>> diff --git a/drivers/hwmon/peci-hwmon.h b/drivers/hwmon/peci-hwmon.h
>>>> new file mode 100644
>>>> index 000000000000..0896c27f33d8
>>>> --- /dev/null
>>>> +++ b/drivers/hwmon/peci-hwmon.h
>>>> @@ -0,0 +1,51 @@
>>>> +/* SPDX-License-Identifier: GPL-2.0 */
>>>> +/* Copyright (c) 2018 Intel Corporation */
>>>> +
>>>> +#ifndef __PECI_HWMON_H
>>>> +#define __PECI_HWMON_H
>>>> +
>>>> +#include <linux/peci.h>
>>>> +
>>>> +#define TEMP_TYPE_PECI         6 /* Sensor type 6: Intel PECI */
>>>> +
>>>> +#define UPDATE_INTERVAL        HZ
>>>> +
>>>> +struct temp_data {
>>>> +	uint  valid;
>>>> +	s32   value;
>>>> +	ulong last_updated;
>>>> +};
>>>> +
>>>> +struct cpu_gen_info {
>>>> +	u16  family;
>>>> +	u8   model;
>>>> +	uint core_max;
>>>> +	uint chan_rank_max;
>>>> +	uint dimm_idx_max;
>>>> +};
>>>> +
>>>> +#define CORE_MAX_ON_HSX        18 /* Max number of cores on Haswell */
>>>> +#define CHAN_RANK_MAX_ON_HSX   8  /* Max number of channel ranks on Haswell */
>>>> +#define DIMM_IDX_MAX_ON_HSX    3  /* Max DIMM index per channel on Haswell */
>>>> +
>>>> +#define CORE_MAX_ON_BDX        24 /* Max number of cores on Broadwell */
>>>> +#define CHAN_RANK_MAX_ON_BDX   4  /* Max number of channel ranks on Broadwell */
>>>> +#define DIMM_IDX_MAX_ON_BDX    3  /* Max DIMM index per channel on Broadwell */
>>>> +
>>>> +#define CORE_MAX_ON_SKX        28 /* Max number of cores on Skylake */
>>>> +#define CHAN_RANK_MAX_ON_SKX   6  /* Max number of channel ranks on Skylake */
>>>> +#define DIMM_IDX_MAX_ON_SKX    2  /* Max DIMM index per channel on Skylake */
>>>> +
>>>> +#define CORE_NUMS_MAX          CORE_MAX_ON_SKX
>>>> +#define CHAN_RANK_MAX          CHAN_RANK_MAX_ON_HSX
>>>> +#define DIMM_IDX_MAX           DIMM_IDX_MAX_ON_HSX
>>>> +#define DIMM_NUMS_MAX          (CHAN_RANK_MAX * DIMM_IDX_MAX)
>>>> +
>>>> +int  peci_hwmon_get_cpu_gen_info(struct peci_adapter *adapter, u8 addr,
>>>> +				 const struct cpu_gen_info **gen_info);
>>>> +bool peci_hwmon_need_update(struct temp_data *temp);
>>>> +void peci_hwmon_mark_updated(struct temp_data *temp);
>>>> +int  peci_hwmon_rd_pkg_cfg_cmd(struct peci_adapter *adapter, u8 addr,
>>>> +			       u8 mbx_idx, u16 param, u8 *data);
>>>> +
>>>> +#endif /* __PECI_HWMON_H */
>>>> -- 
>>>> 2.17.0
>>>>