diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/hwmon/sbrmi.c | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/drivers/hwmon/sbrmi.c b/drivers/hwmon/sbrmi.c new file mode 100644 index 000000000..7bf0c3fba --- /dev/null +++ b/drivers/hwmon/sbrmi.c @@ -0,0 +1,359 @@ +// 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"); |