// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * HWMON driver for ASUS B550/X570 motherboards that publish sensor
 * values via the embedded controller registers.
 *
 * Copyright (C) 2021 Eugene Shalygin <eugene.shalygin@gmail.com>
 * Copyright (C) 2018-2019 Ed Brindley <kernel@maidavale.org>
 *
 * EC provides:
 * - Chipset temperature
 * - CPU temperature
 * - Motherboard temperature
 * - T_Sensor temperature
 * - VRM temperature
 * - Water In temperature
 * - Water Out temperature
 * - CPU Optional Fan RPM
 * - Chipset Fan RPM
 * - Water Flow Fan RPM
 * - CPU current
 */

#include <linux/acpi.h>
#include <linux/dmi.h>
#include <linux/hwmon.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/nls.h>
#include <linux/units.h>
#include <linux/wmi.h>

#include <asm/unaligned.h>

#define ASUSWMI_MONITORING_GUID		"466747A0-70EC-11DE-8A39-0800200C9A66"
#define ASUSWMI_METHODID_BLOCK_READ_EC	0x42524543 /* BREC */
/* From the ASUS DSDT source */
#define ASUSWMI_BREC_REGISTERS_MAX	16
#define ASUSWMI_MAX_BUF_LEN		128
#define SENSOR_LABEL_LEN		16

static u32 hwmon_attributes[hwmon_max] = {
	[hwmon_chip]	= HWMON_C_REGISTER_TZ,
	[hwmon_temp]	= HWMON_T_INPUT | HWMON_T_LABEL,
	[hwmon_in]	= HWMON_I_INPUT | HWMON_I_LABEL,
	[hwmon_curr]	= HWMON_C_INPUT | HWMON_C_LABEL,
	[hwmon_fan]	= HWMON_F_INPUT | HWMON_F_LABEL,
};

struct asus_wmi_ec_sensor_address {
	u8 index;
	u8 bank;
	u8 size;
};

#define MAKE_SENSOR_ADDRESS(size_i, bank_i, index_i) {	\
	.size = size_i,					\
	.bank = bank_i,					\
	.index = index_i,				\
}

struct ec_sensor_info {
	struct asus_wmi_ec_sensor_address addr;
	char label[SENSOR_LABEL_LEN];
	enum hwmon_sensor_types type;
};

#define EC_SENSOR(sensor_label, sensor_type, size, bank, index) {	\
	.addr = MAKE_SENSOR_ADDRESS(size, bank, index),			\
	.label = sensor_label,						\
	.type = sensor_type,						\
}

enum known_ec_sensor {
	SENSOR_TEMP_CHIPSET,
	SENSOR_TEMP_CPU,
	SENSOR_TEMP_MB,
	SENSOR_TEMP_T_SENSOR,
	SENSOR_TEMP_VRM,
	SENSOR_FAN_CPU_OPT,
	SENSOR_FAN_CHIPSET,
	SENSOR_FAN_VRM_HS,
	SENSOR_FAN_WATER_FLOW,
	SENSOR_CURR_CPU,
	SENSOR_TEMP_WATER_IN,
	SENSOR_TEMP_WATER_OUT,
	SENSOR_MAX
};

/* All known sensors for ASUS EC controllers */
static const struct ec_sensor_info known_ec_sensors[] = {
	[SENSOR_TEMP_CHIPSET]	= EC_SENSOR("Chipset", hwmon_temp, 1, 0x00, 0x3a),
	[SENSOR_TEMP_CPU]	= EC_SENSOR("CPU", hwmon_temp, 1, 0x00, 0x3b),
	[SENSOR_TEMP_MB]	= EC_SENSOR("Motherboard", hwmon_temp, 1, 0x00, 0x3c),
	[SENSOR_TEMP_T_SENSOR]	= EC_SENSOR("T_Sensor", hwmon_temp, 1, 0x00, 0x3d),
	[SENSOR_TEMP_VRM]	= EC_SENSOR("VRM", hwmon_temp, 1, 0x00, 0x3e),
	[SENSOR_FAN_CPU_OPT]	= EC_SENSOR("CPU_Opt", hwmon_fan, 2, 0x00, 0xb0),
	[SENSOR_FAN_VRM_HS]	= EC_SENSOR("VRM HS", hwmon_fan, 2, 0x00, 0xb2),
	[SENSOR_FAN_CHIPSET]	= EC_SENSOR("Chipset", hwmon_fan, 2, 0x00, 0xb4),
	[SENSOR_FAN_WATER_FLOW]	= EC_SENSOR("Water_Flow", hwmon_fan, 2, 0x00, 0xbc),
	[SENSOR_CURR_CPU]	= EC_SENSOR("CPU", hwmon_curr, 1, 0x00, 0xf4),
	[SENSOR_TEMP_WATER_IN]	= EC_SENSOR("Water_In", hwmon_temp, 1, 0x01, 0x00),
	[SENSOR_TEMP_WATER_OUT]	= EC_SENSOR("Water_Out", hwmon_temp, 1, 0x01, 0x01),
};

struct asus_wmi_data {
	const enum known_ec_sensor known_board_sensors[SENSOR_MAX + 1];
};

/* boards with EC support */
static struct asus_wmi_data sensors_board_PW_X570_P = {
	.known_board_sensors = {
		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB, SENSOR_TEMP_VRM,
		SENSOR_FAN_CHIPSET,
		SENSOR_MAX
	},
};

static struct asus_wmi_data sensors_board_PW_X570_A = {
	.known_board_sensors = {
		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB, SENSOR_TEMP_VRM,
		SENSOR_FAN_CHIPSET,
		SENSOR_CURR_CPU,
		SENSOR_MAX
	},
};

static struct asus_wmi_data sensors_board_R_C8H = {
	.known_board_sensors = {
		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
		SENSOR_TEMP_WATER_IN, SENSOR_TEMP_WATER_OUT,
		SENSOR_FAN_CPU_OPT, SENSOR_FAN_CHIPSET, SENSOR_FAN_WATER_FLOW,
		SENSOR_CURR_CPU,
		SENSOR_MAX
	},
};

/* Same as Hero but without chipset fan */
static struct asus_wmi_data sensors_board_R_C8DH = {
	.known_board_sensors = {
		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
		SENSOR_TEMP_WATER_IN, SENSOR_TEMP_WATER_OUT,
		SENSOR_FAN_CPU_OPT, SENSOR_FAN_WATER_FLOW,
		SENSOR_CURR_CPU,
		SENSOR_MAX
	},
};

/* Same as Hero but without water */
static struct asus_wmi_data sensors_board_R_C8F = {
	.known_board_sensors = {
		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
		SENSOR_FAN_CPU_OPT, SENSOR_FAN_CHIPSET,
		SENSOR_CURR_CPU,
		SENSOR_MAX
	},
};

static struct asus_wmi_data sensors_board_RS_B550_E_G = {
	.known_board_sensors = {
		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
		SENSOR_FAN_CPU_OPT,
		SENSOR_MAX
	},
};

static struct asus_wmi_data sensors_board_RS_B550_I_G = {
	.known_board_sensors = {
		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
		SENSOR_FAN_VRM_HS,
		SENSOR_CURR_CPU,
		SENSOR_MAX
	},
};

static struct asus_wmi_data sensors_board_RS_X570_E_G = {
	.known_board_sensors = {
		SENSOR_TEMP_CHIPSET, SENSOR_TEMP_CPU, SENSOR_TEMP_MB,
		SENSOR_TEMP_T_SENSOR, SENSOR_TEMP_VRM,
		SENSOR_FAN_CHIPSET,
		SENSOR_CURR_CPU,
		SENSOR_MAX
	},
};

#define DMI_EXACT_MATCH_ASUS_BOARD_NAME(name, sensors) {			\
	.matches = {								\
		DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "ASUSTeK COMPUTER INC."),	\
		DMI_EXACT_MATCH(DMI_BOARD_NAME, name),				\
	},									\
	.driver_data = sensors,							\
}

static const struct dmi_system_id asus_wmi_ec_dmi_table[] = {
	DMI_EXACT_MATCH_ASUS_BOARD_NAME("PRIME X570-PRO", &sensors_board_PW_X570_P),
	DMI_EXACT_MATCH_ASUS_BOARD_NAME("Pro WS X570-ACE", &sensors_board_PW_X570_A),
	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG CROSSHAIR VIII DARK HERO", &sensors_board_R_C8DH),
	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG CROSSHAIR VIII FORMULA", &sensors_board_R_C8F),
	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG CROSSHAIR VIII HERO", &sensors_board_R_C8H),
	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG STRIX B550-E GAMING", &sensors_board_RS_B550_E_G),
	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG STRIX B550-I GAMING", &sensors_board_RS_B550_I_G),
	DMI_EXACT_MATCH_ASUS_BOARD_NAME("ROG STRIX X570-E GAMING", &sensors_board_RS_X570_E_G),
	{}
};
MODULE_DEVICE_TABLE(dmi, asus_wmi_ec_dmi_table);

struct ec_sensor {
	enum known_ec_sensor info_index;
	long cached_value;
};

/**
 * struct asus_wmi_ec_info - sensor info.
 * @sensors: list of sensors.
 * @read_arg: UTF-16LE string to pass to BRxx() WMI function.
 * @read_buffer: decoded output from WMI result.
 * @nr_sensors: number of board EC sensors.
 * @nr_registers: number of EC registers to read (sensor might span more than 1 register).
 * @last_updated: in jiffies.
 */
struct asus_wmi_ec_info {
	struct ec_sensor sensors[SENSOR_MAX];
	char read_arg[(ASUSWMI_BREC_REGISTERS_MAX * 4 + 1) * 2];
	u8 read_buffer[ASUSWMI_BREC_REGISTERS_MAX];
	unsigned int nr_sensors;
	unsigned int nr_registers;
	unsigned long last_updated;
};

struct asus_wmi_sensors {
	struct asus_wmi_ec_info ec;
	/* lock access to internal cache */
	struct mutex lock;
};

static int asus_wmi_ec_fill_board_sensors(struct asus_wmi_ec_info *ec,
					  const enum known_ec_sensor *bsi)
{
	struct ec_sensor *s = ec->sensors;
	int i;

	ec->nr_sensors = 0;
	ec->nr_registers = 0;

	for (i = 0; bsi[i] != SENSOR_MAX; i++) {
		s[i].info_index = bsi[i];
		ec->nr_sensors++;
		ec->nr_registers += known_ec_sensors[bsi[i]].addr.size;
	}

	return 0;
}

/*
 * The next four functions convert to or from BRxx string argument format.
 * The format of the string is as follows:
 * - The string consists of two-byte UTF-16LE characters.
 * - The value of the very first byte in the string is equal to the total
 *   length of the next string in bytes, thus excluding the first two-byte
 *   character.
 * - The rest of the string encodes the pairs of (bank, index) pairs, where
 *   both values are byte-long (0x00 to 0xFF).
 * - Numbers are encoded as UTF-16LE hex values.
 */
static int asus_wmi_ec_decode_reply_buffer(const u8 *in, u32 length, u8 *out)
{
	char buffer[ASUSWMI_MAX_BUF_LEN * 2];
	u32 len = min_t(u32, get_unaligned_le16(in), length - 2);

	utf16s_to_utf8s((wchar_t *)(in + 2), len / 2, UTF16_LITTLE_ENDIAN, buffer, sizeof(buffer));

	return hex2bin(out, buffer, len / 4);
}

static void asus_wmi_ec_encode_registers(const u8 *in, u32 len, char *out)
{
	char buffer[ASUSWMI_MAX_BUF_LEN * 2];

	bin2hex(buffer, in, len);

	utf8s_to_utf16s(buffer, len * 2, UTF16_LITTLE_ENDIAN, (wchar_t *)(out + 2), len * 2);

	put_unaligned_le16(len * 4, out);
}

static void asus_wmi_ec_make_block_read_query(struct asus_wmi_ec_info *ec)
{
	u8 registers[ASUSWMI_BREC_REGISTERS_MAX * 2];
	const struct ec_sensor_info *si;
	int i, j, offset;

	offset = 0;
	for (i = 0; i < ec->nr_sensors; i++) {
		si = &known_ec_sensors[ec->sensors[i].info_index];
		for (j = 0; j < si->addr.size; j++) {
			registers[offset++] = si->addr.bank;
			registers[offset++] = si->addr.index + j;
		}
	}

	asus_wmi_ec_encode_registers(registers, offset, ec->read_arg);
}

static int asus_wmi_ec_block_read(u32 method_id, char *query, u8 *out)
{
	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
	struct acpi_buffer input;
	union acpi_object *obj;
	acpi_status status;
	int ret;

	/* The first byte of the BRxx() argument string has to be the string size. */
	input.length = query[0] + 2;
	input.pointer = query;
	status = wmi_evaluate_method(ASUSWMI_MONITORING_GUID, 0, method_id, &input, &output);
	if (ACPI_FAILURE(status))
		return -EIO;

	obj = output.pointer;
	if (!obj)
		return -EIO;

	if (obj->type != ACPI_TYPE_BUFFER || obj->buffer.length < 2) {
		ret = -EIO;
		goto out_free_obj;
	}

	ret = asus_wmi_ec_decode_reply_buffer(obj->buffer.pointer, obj->buffer.length, out);

out_free_obj:
	ACPI_FREE(obj);
	return ret;
}

static inline long get_sensor_value(const struct ec_sensor_info *si, u8 *data)
{
	switch (si->addr.size) {
	case 1:
		return *data;
	case 2:
		return get_unaligned_be16(data);
	case 4:
		return get_unaligned_be32(data);
	default:
		return 0;
	}
}

static void asus_wmi_ec_update_ec_sensors(struct asus_wmi_ec_info *ec)
{
	const struct ec_sensor_info *si;
	struct ec_sensor *s;
	u8 i_sensor;
	u8 *data;

	data = ec->read_buffer;
	for (i_sensor = 0; i_sensor < ec->nr_sensors; i_sensor++) {
		s = &ec->sensors[i_sensor];
		si = &known_ec_sensors[s->info_index];
		s->cached_value = get_sensor_value(si, data);
		data += si->addr.size;
	}
}

static long asus_wmi_ec_scale_sensor_value(long value, int data_type)
{
	switch (data_type) {
	case hwmon_curr:
	case hwmon_temp:
	case hwmon_in:
		return value * MILLI;
	default:
		return value;
	}
}

static int asus_wmi_ec_find_sensor_index(const struct asus_wmi_ec_info *ec,
					 enum hwmon_sensor_types type, int channel)
{
	int i;

	for (i = 0; i < ec->nr_sensors; i++) {
		if (known_ec_sensors[ec->sensors[i].info_index].type == type) {
			if (channel == 0)
				return i;

			channel--;
		}
	}
	return -EINVAL;
}

static int asus_wmi_ec_get_cached_value_or_update(struct asus_wmi_sensors *sensor_data,
						  int sensor_index,
						  long *value)
{
	struct asus_wmi_ec_info *ec = &sensor_data->ec;
	int ret = 0;

	mutex_lock(&sensor_data->lock);

	if (time_after(jiffies, ec->last_updated + HZ)) {
		ret = asus_wmi_ec_block_read(ASUSWMI_METHODID_BLOCK_READ_EC,
					     ec->read_arg, ec->read_buffer);
		if (ret)
			goto unlock;

		asus_wmi_ec_update_ec_sensors(ec);
		ec->last_updated = jiffies;
	}

	*value = ec->sensors[sensor_index].cached_value;

unlock:
	mutex_unlock(&sensor_data->lock);

	return ret;
}

/* Now follow the functions that implement the hwmon interface */

static int asus_wmi_ec_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
				  u32 attr, int channel, long *val)
{
	struct asus_wmi_sensors *sensor_data = dev_get_drvdata(dev);
	struct asus_wmi_ec_info *ec = &sensor_data->ec;
	int ret, sidx, info_index;
	long value = 0;

	sidx = asus_wmi_ec_find_sensor_index(ec, type, channel);
	if (sidx < 0)
		return sidx;

	ret = asus_wmi_ec_get_cached_value_or_update(sensor_data, sidx, &value);
	if (ret)
		return ret;

	info_index = ec->sensors[sidx].info_index;
	*val = asus_wmi_ec_scale_sensor_value(value, known_ec_sensors[info_index].type);

	return ret;
}

static int asus_wmi_ec_hwmon_read_string(struct device *dev,
					 enum hwmon_sensor_types type, u32 attr,
					 int channel, const char **str)
{
	struct asus_wmi_sensors *sensor_data = dev_get_drvdata(dev);
	struct asus_wmi_ec_info *ec = &sensor_data->ec;
	int sensor_index;

	sensor_index = asus_wmi_ec_find_sensor_index(ec, type, channel);
	*str = known_ec_sensors[ec->sensors[sensor_index].info_index].label;

	return 0;
}

static umode_t asus_wmi_ec_hwmon_is_visible(const void *drvdata,
					    enum hwmon_sensor_types type, u32 attr,
					    int channel)
{
	const struct asus_wmi_sensors *sensor_data = drvdata;
	const struct asus_wmi_ec_info *ec = &sensor_data->ec;
	int index;

	index = asus_wmi_ec_find_sensor_index(ec, type, channel);

	return index < 0 ? 0 : 0444;
}

static int asus_wmi_hwmon_add_chan_info(struct hwmon_channel_info *asus_wmi_hwmon_chan,
					struct device *dev, int num,
					enum hwmon_sensor_types type, u32 config)
{
	u32 *cfg;

	cfg = devm_kcalloc(dev, num + 1, sizeof(*cfg), GFP_KERNEL);
	if (!cfg)
		return -ENOMEM;

	asus_wmi_hwmon_chan->type = type;
	asus_wmi_hwmon_chan->config = cfg;
	memset32(cfg, config, num);

	return 0;
}

static const struct hwmon_ops asus_wmi_ec_hwmon_ops = {
	.is_visible = asus_wmi_ec_hwmon_is_visible,
	.read = asus_wmi_ec_hwmon_read,
	.read_string = asus_wmi_ec_hwmon_read_string,
};

static struct hwmon_chip_info asus_wmi_ec_chip_info = {
	.ops = &asus_wmi_ec_hwmon_ops,
};

static int asus_wmi_ec_configure_sensor_setup(struct device *dev,
					      const enum known_ec_sensor *bsi)
{
	struct asus_wmi_sensors *sensor_data = dev_get_drvdata(dev);
	struct asus_wmi_ec_info *ec = &sensor_data->ec;
	struct hwmon_channel_info *asus_wmi_hwmon_chan;
	const struct hwmon_channel_info **asus_wmi_ci;
	int nr_count[hwmon_max] = {}, nr_types = 0;
	const struct hwmon_chip_info *chip_info;
	const struct ec_sensor_info *si;
	enum hwmon_sensor_types type;
	struct device *hwdev;
	int i, ret;

	ret = asus_wmi_ec_fill_board_sensors(ec, bsi);
	if (ret)
		return ret;

	if (!sensor_data->ec.nr_sensors)
		return -ENODEV;

	for (i = 0; i < ec->nr_sensors; i++) {
		si = &known_ec_sensors[ec->sensors[i].info_index];
		if (!nr_count[si->type])
			nr_types++;
		nr_count[si->type]++;
	}

	if (nr_count[hwmon_temp]) {
		nr_count[hwmon_chip]++;
		nr_types++;
	}

	/*
	 * If we can get values for all the registers in a single query,
	 * the query will not change from call to call.
	 */
	asus_wmi_ec_make_block_read_query(ec);

	asus_wmi_hwmon_chan = devm_kcalloc(dev, nr_types, sizeof(*asus_wmi_hwmon_chan),
					   GFP_KERNEL);
	if (!asus_wmi_hwmon_chan)
		return -ENOMEM;

	asus_wmi_ci = devm_kcalloc(dev, nr_types + 1, sizeof(*asus_wmi_ci), GFP_KERNEL);
	if (!asus_wmi_ci)
		return -ENOMEM;

	asus_wmi_ec_chip_info.info = asus_wmi_ci;
	chip_info = &asus_wmi_ec_chip_info;

	for (type = 0; type < hwmon_max; type++) {
		if (!nr_count[type])
			continue;

		ret = asus_wmi_hwmon_add_chan_info(asus_wmi_hwmon_chan, dev,
						   nr_count[type], type,
						   hwmon_attributes[type]);
		if (ret)
			return ret;

		*asus_wmi_ci++ = asus_wmi_hwmon_chan++;
	}

	dev_dbg(dev, "board has %d EC sensors that span %d registers",
		ec->nr_sensors, ec->nr_registers);

	hwdev = devm_hwmon_device_register_with_info(dev, "asus_wmi_ec_sensors",
						     sensor_data, chip_info, NULL);

	return PTR_ERR_OR_ZERO(hwdev);
}

static int asus_wmi_probe(struct wmi_device *wdev, const void *context)
{
	struct asus_wmi_sensors *sensor_data;
	struct asus_wmi_data *board_sensors;
	const struct dmi_system_id *dmi_id;
	const enum known_ec_sensor *bsi;
	struct device *dev = &wdev->dev;

	dmi_id = dmi_first_match(asus_wmi_ec_dmi_table);
	if (!dmi_id)
		return -ENODEV;

	board_sensors = dmi_id->driver_data;
	bsi = board_sensors->known_board_sensors;

	sensor_data = devm_kzalloc(dev, sizeof(*sensor_data), GFP_KERNEL);
	if (!sensor_data)
		return -ENOMEM;

	mutex_init(&sensor_data->lock);

	dev_set_drvdata(dev, sensor_data);

	return asus_wmi_ec_configure_sensor_setup(dev, bsi);
}

static const struct wmi_device_id asus_ec_wmi_id_table[] = {
	{ ASUSWMI_MONITORING_GUID, NULL },
	{ }
};

static struct wmi_driver asus_sensors_wmi_driver = {
	.driver = {
		.name = "asus_wmi_ec_sensors",
	},
	.id_table = asus_ec_wmi_id_table,
	.probe = asus_wmi_probe,
};
module_wmi_driver(asus_sensors_wmi_driver);

MODULE_AUTHOR("Ed Brindley <kernel@maidavale.org>");
MODULE_AUTHOR("Eugene Shalygin <eugene.shalygin@gmail.com>");
MODULE_DESCRIPTION("Asus WMI Sensors Driver");
MODULE_LICENSE("GPL");