drivers/hwmon/sbrmi.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * sbrmi.c - hwmon driver for a SB-RMI mailbox
  *           compliant AMD SoC device.
  *
  * Copyright (C) 2020-2021 Advanced Micro Devices, Inc.
  */

 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/hwmon.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>

 /* Do not allow setting negative power limit */
 #define SBRMI_PWR_MIN	0
 /* Mask for Status Register bit[1] */
 #define SW_ALERT_MASK	0x2

 /* Software Interrupt for triggering */
 #define START_CMD	0x80
 #define TRIGGER_MAILBOX	0x01

 /*
  * SB-RMI supports soft mailbox service request to MP1 (power management
  * firmware) through SBRMI inbound/outbound message registers.
  * SB-RMI message IDs
  */
 enum sbrmi_msg_id {
 	SBRMI_READ_PKG_PWR_CONSUMPTION = 0x1,
 	SBRMI_WRITE_PKG_PWR_LIMIT,
 	SBRMI_READ_PKG_PWR_LIMIT,
 	SBRMI_READ_PKG_MAX_PWR_LIMIT,
 };

 /* SB-RMI registers */
 enum sbrmi_reg {
 	SBRMI_CTRL		= 0x01,
 	SBRMI_STATUS,
 	SBRMI_OUTBNDMSG0	= 0x30,
 	SBRMI_OUTBNDMSG1,
 	SBRMI_OUTBNDMSG2,
 	SBRMI_OUTBNDMSG3,
 	SBRMI_OUTBNDMSG4,
 	SBRMI_OUTBNDMSG5,
 	SBRMI_OUTBNDMSG6,
 	SBRMI_OUTBNDMSG7,
 	SBRMI_INBNDMSG0,
 	SBRMI_INBNDMSG1,
 	SBRMI_INBNDMSG2,
 	SBRMI_INBNDMSG3,
 	SBRMI_INBNDMSG4,
 	SBRMI_INBNDMSG5,
 	SBRMI_INBNDMSG6,
 	SBRMI_INBNDMSG7,
 	SBRMI_SW_INTERRUPT,
 };

 /* Each client has this additional data */
 struct sbrmi_data {
 	struct i2c_client *client;
 	struct mutex lock;
 	u32 pwr_limit_max;
 };

 struct sbrmi_mailbox_msg {
 	u8 cmd;
 	bool read;
 	u32 data_in;
 	u32 data_out;
 };

 static int sbrmi_enable_alert(struct i2c_client *client)
 {
 	int ctrl;

 	/*
 	 * Enable the SB-RMI Software alert status
 	 * by writing 0 to bit 4 of Control register(0x1)
 	 */
 	ctrl = i2c_smbus_read_byte_data(client, SBRMI_CTRL);
 	if (ctrl < 0)
 		return ctrl;

 	if (ctrl & 0x10) {
 		ctrl &= ~0x10;
 		return i2c_smbus_write_byte_data(client,
 						 SBRMI_CTRL, ctrl);
 	}

 	return 0;
 }

 static int rmi_mailbox_xfer(struct sbrmi_data *data,
 			    struct sbrmi_mailbox_msg *msg)
 {
 	int i, ret, retry = 10;
 	int sw_status;
 	u8 byte;

 	mutex_lock(&data->lock);

 	/* Indicate firmware a command is to be serviced */
 	ret = i2c_smbus_write_byte_data(data->client,
 					SBRMI_INBNDMSG7, START_CMD);
 	if (ret < 0)
 		goto exit_unlock;

 	/* Write the command to SBRMI::InBndMsg_inst0 */
 	ret = i2c_smbus_write_byte_data(data->client,
 					SBRMI_INBNDMSG0, msg->cmd);
 	if (ret < 0)
 		goto exit_unlock;

 	/*
 	 * For both read and write the initiator (BMC) writes
 	 * Command Data In[31:0] to SBRMI::InBndMsg_inst[4:1]
 	 * SBRMI_x3C(MSB):SBRMI_x39(LSB)
 	 */
 	for (i = 0; i < 4; i++) {
 		byte = (msg->data_in >> i * 8) & 0xff;
 		ret = i2c_smbus_write_byte_data(data->client,
 						SBRMI_INBNDMSG1 + i, byte);
 		if (ret < 0)
 			goto exit_unlock;
 	}

 	/*
 	 * Write 0x01 to SBRMI::SoftwareInterrupt to notify firmware to
 	 * perform the requested read or write command
 	 */
 	ret = i2c_smbus_write_byte_data(data->client,
 					SBRMI_SW_INTERRUPT, TRIGGER_MAILBOX);
 	if (ret < 0)
 		goto exit_unlock;

 	/*
 	 * Firmware will write SBRMI::Status[SwAlertSts]=1 to generate
 	 * an ALERT (if enabled) to initiator (BMC) to indicate completion
 	 * of the requested command
 	 */
 	do {
 		sw_status = i2c_smbus_read_byte_data(data->client,
 						     SBRMI_STATUS);
 		if (sw_status < 0) {
 			ret = sw_status;
 			goto exit_unlock;
 		}
 		if (sw_status & SW_ALERT_MASK)
 			break;
 		usleep_range(50, 100);
 	} while (retry--);

 	if (retry < 0) {
 		dev_err(&data->client->dev,
 			"Firmware fail to indicate command completion\n");
 		ret = -EIO;
 		goto exit_unlock;
 	}

 	/*
 	 * For a read operation, the initiator (BMC) reads the firmware
 	 * response Command Data Out[31:0] from SBRMI::OutBndMsg_inst[4:1]
 	 * {SBRMI_x34(MSB):SBRMI_x31(LSB)}.
 	 */
 	if (msg->read) {
 		for (i = 0; i < 4; i++) {
 			ret = i2c_smbus_read_byte_data(data->client,
 						       SBRMI_OUTBNDMSG1 + i);
 			if (ret < 0)
 				goto exit_unlock;
 			msg->data_out |= ret << i * 8;
 		}
 	}

 	/*
 	 * BMC must write 1'b1 to SBRMI::Status[SwAlertSts] to clear the
 	 * ALERT to initiator
 	 */
 	ret = i2c_smbus_write_byte_data(data->client, SBRMI_STATUS,
 					sw_status | SW_ALERT_MASK);

 exit_unlock:
 	mutex_unlock(&data->lock);
 	return ret;
 }

 static int sbrmi_read(struct device *dev, enum hwmon_sensor_types type,
 		      u32 attr, int channel, long *val)
 {
 	struct sbrmi_data *data = dev_get_drvdata(dev);
 	struct sbrmi_mailbox_msg msg = { 0 };
 	int ret;

 	if (type != hwmon_power)
 		return -EINVAL;

 	msg.read = true;
 	switch (attr) {
 	case hwmon_power_input:
 		msg.cmd = SBRMI_READ_PKG_PWR_CONSUMPTION;
 		ret = rmi_mailbox_xfer(data, &msg);
 		break;
 	case hwmon_power_cap:
 		msg.cmd = SBRMI_READ_PKG_PWR_LIMIT;
 		ret = rmi_mailbox_xfer(data, &msg);
 		break;
 	case hwmon_power_cap_max:
 		msg.data_out = data->pwr_limit_max;
 		ret = 0;
 		break;
 	default:
 		return -EINVAL;
 	}
 	if (ret < 0)
 		return ret;
 	/* hwmon power attributes are in microWatt */
 	*val = (long)msg.data_out * 1000;
 	return ret;
 }

 static int sbrmi_write(struct device *dev, enum hwmon_sensor_types type,
 		       u32 attr, int channel, long val)
 {
 	struct sbrmi_data *data = dev_get_drvdata(dev);
 	struct sbrmi_mailbox_msg msg = { 0 };

 	if (type != hwmon_power && attr != hwmon_power_cap)
 		return -EINVAL;
 	/*
 	 * hwmon power attributes are in microWatt
 	 * mailbox read/write is in mWatt
 	 */
 	val /= 1000;

 	val = clamp_val(val, SBRMI_PWR_MIN, data->pwr_limit_max);

 	msg.cmd = SBRMI_WRITE_PKG_PWR_LIMIT;
 	msg.data_in = val;
 	msg.read = false;

 	return rmi_mailbox_xfer(data, &msg);
 }

 static umode_t sbrmi_is_visible(const void *data,
 				enum hwmon_sensor_types type,
 				u32 attr, int channel)
 {
 	switch (type) {
 	case hwmon_power:
 		switch (attr) {
 		case hwmon_power_input:
 		case hwmon_power_cap_max:
 			return 0444;
 		case hwmon_power_cap:
 			return 0644;
 		}
 		break;
 	default:
 		break;
 	}
 	return 0;
 }

 static const struct hwmon_channel_info *sbrmi_info[] = {
 	HWMON_CHANNEL_INFO(power,
 			   HWMON_P_INPUT | HWMON_P_CAP | HWMON_P_CAP_MAX),
 	NULL
 };

 static const struct hwmon_ops sbrmi_hwmon_ops = {
 	.is_visible = sbrmi_is_visible,
 	.read = sbrmi_read,
 	.write = sbrmi_write,
 };

 static const struct hwmon_chip_info sbrmi_chip_info = {
 	.ops = &sbrmi_hwmon_ops,
 	.info = sbrmi_info,
 };

 static int sbrmi_get_max_pwr_limit(struct sbrmi_data *data)
 {
 	struct sbrmi_mailbox_msg msg = { 0 };
 	int ret;

 	msg.cmd = SBRMI_READ_PKG_MAX_PWR_LIMIT;
 	msg.read = true;
 	ret = rmi_mailbox_xfer(data, &msg);
 	if (ret < 0)
 		return ret;
 	data->pwr_limit_max = msg.data_out;

 	return ret;
 }

 static int sbrmi_probe(struct i2c_client *client,
 		       const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
 	struct device *hwmon_dev;
 	struct sbrmi_data *data;
 	int ret;

 	data = devm_kzalloc(dev, sizeof(struct sbrmi_data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	data->client = client;
 	mutex_init(&data->lock);

 	/* Enable alert for SB-RMI sequence */
 	ret = sbrmi_enable_alert(client);
 	if (ret < 0)
 		return ret;

 	/* Cache maximum power limit */
 	ret = sbrmi_get_max_pwr_limit(data);
 	if (ret < 0)
 		return ret;

 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
 							 &sbrmi_chip_info, NULL);

 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }

 static const struct i2c_device_id sbrmi_id[] = {
 	{"sbrmi", 0},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, sbrmi_id);

 static const struct of_device_id __maybe_unused sbrmi_of_match[] = {
 	{
 		.compatible = "amd,sbrmi",
 	},
 	{ },
 };
 MODULE_DEVICE_TABLE(of, sbrmi_of_match);

 static struct i2c_driver sbrmi_driver = {
 	.class = I2C_CLASS_HWMON,
 	.driver = {
 		.name = "sbrmi",
 		.of_match_table = of_match_ptr(sbrmi_of_match),
 	},
 	.probe = sbrmi_probe,
 	.id_table = sbrmi_id,
 };

 module_i2c_driver(sbrmi_driver);

 MODULE_AUTHOR("Akshay Gupta <akshay.gupta@amd.com>");
 MODULE_DESCRIPTION("Hwmon driver for AMD SB-RMI emulated sensor");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* sbrmi.c - hwmon driver for a SB-RMI mailbox
	* compliant AMD SoC device.
	*
	* Copyright (C) 2020-2021 Advanced Micro Devices, Inc.
	*/

	#include <linux/delay.h>
	#include <linux/err.h>
	#include <linux/hwmon.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>

	/* Do not allow setting negative power limit */
	#define SBRMI_PWR_MIN 0
	/* Mask for Status Register bit[1] */
	#define SW_ALERT_MASK 0x2

	/* Software Interrupt for triggering */
	#define START_CMD 0x80
	#define TRIGGER_MAILBOX 0x01

	/*
	* SB-RMI supports soft mailbox service request to MP1 (power management
	* firmware) through SBRMI inbound/outbound message registers.
	* SB-RMI message IDs
	*/
	enum sbrmi_msg_id {
	SBRMI_READ_PKG_PWR_CONSUMPTION = 0x1,
	SBRMI_WRITE_PKG_PWR_LIMIT,
	SBRMI_READ_PKG_PWR_LIMIT,
	SBRMI_READ_PKG_MAX_PWR_LIMIT,
	};

	/* SB-RMI registers */
	enum sbrmi_reg {
	SBRMI_CTRL = 0x01,
	SBRMI_STATUS,
	SBRMI_OUTBNDMSG0 = 0x30,
	SBRMI_OUTBNDMSG1,
	SBRMI_OUTBNDMSG2,
	SBRMI_OUTBNDMSG3,
	SBRMI_OUTBNDMSG4,
	SBRMI_OUTBNDMSG5,
	SBRMI_OUTBNDMSG6,
	SBRMI_OUTBNDMSG7,
	SBRMI_INBNDMSG0,
	SBRMI_INBNDMSG1,
	SBRMI_INBNDMSG2,
	SBRMI_INBNDMSG3,
	SBRMI_INBNDMSG4,
	SBRMI_INBNDMSG5,
	SBRMI_INBNDMSG6,
	SBRMI_INBNDMSG7,
	SBRMI_SW_INTERRUPT,
	};

	/* Each client has this additional data */
	struct sbrmi_data {
	struct i2c_client *client;
	struct mutex lock;
	u32 pwr_limit_max;
	};

	struct sbrmi_mailbox_msg {
	u8 cmd;
	bool read;
	u32 data_in;
	u32 data_out;
	};

	static int sbrmi_enable_alert(struct i2c_client *client)
	{
	int ctrl;

	/*
	* Enable the SB-RMI Software alert status
	* by writing 0 to bit 4 of Control register(0x1)
	*/
	ctrl = i2c_smbus_read_byte_data(client, SBRMI_CTRL);
	if (ctrl < 0)
	return ctrl;

	if (ctrl & 0x10) {
	ctrl &= ~0x10;
	return i2c_smbus_write_byte_data(client,
	SBRMI_CTRL, ctrl);
	}

	return 0;
	}

	static int rmi_mailbox_xfer(struct sbrmi_data *data,
	struct sbrmi_mailbox_msg *msg)
	{
	int i, ret, retry = 10;
	int sw_status;
	u8 byte;

	mutex_lock(&data->lock);

	/* Indicate firmware a command is to be serviced */
	ret = i2c_smbus_write_byte_data(data->client,
	SBRMI_INBNDMSG7, START_CMD);
	if (ret < 0)
	goto exit_unlock;

	/* Write the command to SBRMI::InBndMsg_inst0 */
	ret = i2c_smbus_write_byte_data(data->client,
	SBRMI_INBNDMSG0, msg->cmd);
	if (ret < 0)
	goto exit_unlock;

	/*
	* For both read and write the initiator (BMC) writes
	* Command Data In[31:0] to SBRMI::InBndMsg_inst[4:1]
	* SBRMI_x3C(MSB):SBRMI_x39(LSB)
	*/
	for (i = 0; i < 4; i++) {
	byte = (msg->data_in >> i * 8) & 0xff;
	ret = i2c_smbus_write_byte_data(data->client,
	SBRMI_INBNDMSG1 + i, byte);
	if (ret < 0)
	goto exit_unlock;
	}

	/*
	* Write 0x01 to SBRMI::SoftwareInterrupt to notify firmware to
	* perform the requested read or write command
	*/
	ret = i2c_smbus_write_byte_data(data->client,
	SBRMI_SW_INTERRUPT, TRIGGER_MAILBOX);
	if (ret < 0)
	goto exit_unlock;

	/*
	* Firmware will write SBRMI::Status[SwAlertSts]=1 to generate
	* an ALERT (if enabled) to initiator (BMC) to indicate completion
	* of the requested command
	*/
	do {
	sw_status = i2c_smbus_read_byte_data(data->client,
	SBRMI_STATUS);
	if (sw_status < 0) {
	ret = sw_status;
	goto exit_unlock;
	}
	if (sw_status & SW_ALERT_MASK)
	break;
	usleep_range(50, 100);
	} while (retry--);

	if (retry < 0) {
	dev_err(&data->client->dev,
	"Firmware fail to indicate command completion\n");
	ret = -EIO;
	goto exit_unlock;
	}

	/*
	* For a read operation, the initiator (BMC) reads the firmware
	* response Command Data Out[31:0] from SBRMI::OutBndMsg_inst[4:1]
	* {SBRMI_x34(MSB):SBRMI_x31(LSB)}.
	*/
	if (msg->read) {
	for (i = 0; i < 4; i++) {
	ret = i2c_smbus_read_byte_data(data->client,
	SBRMI_OUTBNDMSG1 + i);
	if (ret < 0)
	goto exit_unlock;
	msg->data_out \|= ret << i * 8;
	}
	}

	/*
	* BMC must write 1'b1 to SBRMI::Status[SwAlertSts] to clear the
	* ALERT to initiator
	*/
	ret = i2c_smbus_write_byte_data(data->client, SBRMI_STATUS,
	sw_status \| SW_ALERT_MASK);

	exit_unlock:
	mutex_unlock(&data->lock);
	return ret;
	}

	static int sbrmi_read(struct device *dev, enum hwmon_sensor_types type,
	u32 attr, int channel, long *val)
	{
	struct sbrmi_data *data = dev_get_drvdata(dev);
	struct sbrmi_mailbox_msg msg = { 0 };
	int ret;

	if (type != hwmon_power)
	return -EINVAL;

	msg.read = true;
	switch (attr) {
	case hwmon_power_input:
	msg.cmd = SBRMI_READ_PKG_PWR_CONSUMPTION;
	ret = rmi_mailbox_xfer(data, &msg);
	break;
	case hwmon_power_cap:
	msg.cmd = SBRMI_READ_PKG_PWR_LIMIT;
	ret = rmi_mailbox_xfer(data, &msg);
	break;
	case hwmon_power_cap_max:
	msg.data_out = data->pwr_limit_max;
	ret = 0;
	break;
	default:
	return -EINVAL;
	}
	if (ret < 0)
	return ret;
	/* hwmon power attributes are in microWatt */
	val = (long)msg.data_out 1000;
	return ret;
	}

	static int sbrmi_write(struct device *dev, enum hwmon_sensor_types type,
	u32 attr, int channel, long val)
	{
	struct sbrmi_data *data = dev_get_drvdata(dev);
	struct sbrmi_mailbox_msg msg = { 0 };

	if (type != hwmon_power && attr != hwmon_power_cap)
	return -EINVAL;
	/*
	* hwmon power attributes are in microWatt
	* mailbox read/write is in mWatt
	*/
	val /= 1000;

	val = clamp_val(val, SBRMI_PWR_MIN, data->pwr_limit_max);

	msg.cmd = SBRMI_WRITE_PKG_PWR_LIMIT;
	msg.data_in = val;
	msg.read = false;

	return rmi_mailbox_xfer(data, &msg);
	}

	static umode_t sbrmi_is_visible(const void *data,
	enum hwmon_sensor_types type,
	u32 attr, int channel)
	{
	switch (type) {
	case hwmon_power:
	switch (attr) {
	case hwmon_power_input:
	case hwmon_power_cap_max:
	return 0444;
	case hwmon_power_cap:
	return 0644;
	}
	break;
	default:
	break;
	}
	return 0;
	}

	static const struct hwmon_channel_info *sbrmi_info[] = {
	HWMON_CHANNEL_INFO(power,
	HWMON_P_INPUT \| HWMON_P_CAP \| HWMON_P_CAP_MAX),
	NULL
	};

	static const struct hwmon_ops sbrmi_hwmon_ops = {
	.is_visible = sbrmi_is_visible,
	.read = sbrmi_read,
	.write = sbrmi_write,
	};

	static const struct hwmon_chip_info sbrmi_chip_info = {
	.ops = &sbrmi_hwmon_ops,
	.info = sbrmi_info,
	};

	static int sbrmi_get_max_pwr_limit(struct sbrmi_data *data)
	{
	struct sbrmi_mailbox_msg msg = { 0 };
	int ret;

	msg.cmd = SBRMI_READ_PKG_MAX_PWR_LIMIT;
	msg.read = true;
	ret = rmi_mailbox_xfer(data, &msg);
	if (ret < 0)
	return ret;
	data->pwr_limit_max = msg.data_out;

	return ret;
	}

	static int sbrmi_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct device *dev = &client->dev;
	struct device *hwmon_dev;
	struct sbrmi_data *data;
	int ret;

	data = devm_kzalloc(dev, sizeof(struct sbrmi_data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	data->client = client;
	mutex_init(&data->lock);

	/* Enable alert for SB-RMI sequence */
	ret = sbrmi_enable_alert(client);
	if (ret < 0)
	return ret;

	/* Cache maximum power limit */
	ret = sbrmi_get_max_pwr_limit(data);
	if (ret < 0)
	return ret;

	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
	&sbrmi_chip_info, NULL);

	return PTR_ERR_OR_ZERO(hwmon_dev);
	}

	static const struct i2c_device_id sbrmi_id[] = {
	{"sbrmi", 0},
	{}
	};
	MODULE_DEVICE_TABLE(i2c, sbrmi_id);

	static const struct of_device_id __maybe_unused sbrmi_of_match[] = {
	{
	.compatible = "amd,sbrmi",
	},
	{ },
	};
	MODULE_DEVICE_TABLE(of, sbrmi_of_match);

	static struct i2c_driver sbrmi_driver = {
	.class = I2C_CLASS_HWMON,
	.driver = {
	.name = "sbrmi",
	.of_match_table = of_match_ptr(sbrmi_of_match),
	},
	.probe = sbrmi_probe,
	.id_table = sbrmi_id,
	};

	module_i2c_driver(sbrmi_driver);

	MODULE_AUTHOR("Akshay Gupta <akshay.gupta@amd.com>");
	MODULE_DESCRIPTION("Hwmon driver for AMD SB-RMI emulated sensor");
	MODULE_LICENSE("GPL");