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5a0f50d110
On AMD platforms the Out-of-band access is provided by Advanced Platform Management Link (APML), APML is a SMBus v2.0 compatible 2-wire processor client interface. APML is also referred as the sideband interface (SBI). APML is used to communicate with the Side-Band Remote Management Interface (SB-RMI) which provides Soft Mailbox messages to manage power consumption and power limits of the CPU socket. - This module add support to read power consumption, power limit & max power limit and write power limit. - To instantiate this driver on a Board Management Controller (BMC) connected to an AMD CPU with SB-RMI support, the i2c bus number would be the bus connected from the BMC to the CPU. Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Akshay Gupta <Akshay.Gupta@amd.com> Signed-off-by: Naveen Krishna Chatradhi <nchatrad@amd.com> Link: https://lore.kernel.org/r/20210726133615.9709-1-nchatrad@amd.com [groeck: Fix uninitialized variable problem when reporting max power] Signed-off-by: Guenter Roeck <linux@roeck-us.net>
360 lines
7.7 KiB
C
360 lines
7.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* sbrmi.c - hwmon driver for a SB-RMI mailbox
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* compliant AMD SoC device.
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*
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* Copyright (C) 2020-2021 Advanced Micro Devices, Inc.
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*/
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/hwmon.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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/* Do not allow setting negative power limit */
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#define SBRMI_PWR_MIN 0
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/* Mask for Status Register bit[1] */
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#define SW_ALERT_MASK 0x2
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/* Software Interrupt for triggering */
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#define START_CMD 0x80
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#define TRIGGER_MAILBOX 0x01
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/*
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* SB-RMI supports soft mailbox service request to MP1 (power management
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* firmware) through SBRMI inbound/outbound message registers.
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* SB-RMI message IDs
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*/
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enum sbrmi_msg_id {
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SBRMI_READ_PKG_PWR_CONSUMPTION = 0x1,
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SBRMI_WRITE_PKG_PWR_LIMIT,
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SBRMI_READ_PKG_PWR_LIMIT,
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SBRMI_READ_PKG_MAX_PWR_LIMIT,
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};
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/* SB-RMI registers */
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enum sbrmi_reg {
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SBRMI_CTRL = 0x01,
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SBRMI_STATUS,
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SBRMI_OUTBNDMSG0 = 0x30,
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SBRMI_OUTBNDMSG1,
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SBRMI_OUTBNDMSG2,
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SBRMI_OUTBNDMSG3,
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SBRMI_OUTBNDMSG4,
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SBRMI_OUTBNDMSG5,
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SBRMI_OUTBNDMSG6,
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SBRMI_OUTBNDMSG7,
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SBRMI_INBNDMSG0,
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SBRMI_INBNDMSG1,
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SBRMI_INBNDMSG2,
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SBRMI_INBNDMSG3,
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SBRMI_INBNDMSG4,
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SBRMI_INBNDMSG5,
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SBRMI_INBNDMSG6,
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SBRMI_INBNDMSG7,
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SBRMI_SW_INTERRUPT,
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};
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/* Each client has this additional data */
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struct sbrmi_data {
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struct i2c_client *client;
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struct mutex lock;
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u32 pwr_limit_max;
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};
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struct sbrmi_mailbox_msg {
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u8 cmd;
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bool read;
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u32 data_in;
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u32 data_out;
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};
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static int sbrmi_enable_alert(struct i2c_client *client)
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{
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int ctrl;
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/*
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* Enable the SB-RMI Software alert status
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* by writing 0 to bit 4 of Control register(0x1)
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*/
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ctrl = i2c_smbus_read_byte_data(client, SBRMI_CTRL);
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if (ctrl < 0)
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return ctrl;
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if (ctrl & 0x10) {
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ctrl &= ~0x10;
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return i2c_smbus_write_byte_data(client,
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SBRMI_CTRL, ctrl);
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}
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return 0;
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}
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static int rmi_mailbox_xfer(struct sbrmi_data *data,
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struct sbrmi_mailbox_msg *msg)
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{
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int i, ret, retry = 10;
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int sw_status;
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u8 byte;
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mutex_lock(&data->lock);
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/* Indicate firmware a command is to be serviced */
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ret = i2c_smbus_write_byte_data(data->client,
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SBRMI_INBNDMSG7, START_CMD);
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if (ret < 0)
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goto exit_unlock;
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/* Write the command to SBRMI::InBndMsg_inst0 */
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ret = i2c_smbus_write_byte_data(data->client,
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SBRMI_INBNDMSG0, msg->cmd);
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if (ret < 0)
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goto exit_unlock;
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/*
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* For both read and write the initiator (BMC) writes
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* Command Data In[31:0] to SBRMI::InBndMsg_inst[4:1]
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* SBRMI_x3C(MSB):SBRMI_x39(LSB)
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*/
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for (i = 0; i < 4; i++) {
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byte = (msg->data_in >> i * 8) & 0xff;
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ret = i2c_smbus_write_byte_data(data->client,
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SBRMI_INBNDMSG1 + i, byte);
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if (ret < 0)
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goto exit_unlock;
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}
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/*
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* Write 0x01 to SBRMI::SoftwareInterrupt to notify firmware to
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* perform the requested read or write command
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*/
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ret = i2c_smbus_write_byte_data(data->client,
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SBRMI_SW_INTERRUPT, TRIGGER_MAILBOX);
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if (ret < 0)
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goto exit_unlock;
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/*
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* Firmware will write SBRMI::Status[SwAlertSts]=1 to generate
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* an ALERT (if enabled) to initiator (BMC) to indicate completion
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* of the requested command
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*/
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do {
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sw_status = i2c_smbus_read_byte_data(data->client,
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SBRMI_STATUS);
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if (sw_status < 0) {
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ret = sw_status;
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goto exit_unlock;
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}
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if (sw_status & SW_ALERT_MASK)
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break;
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usleep_range(50, 100);
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} while (retry--);
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if (retry < 0) {
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dev_err(&data->client->dev,
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"Firmware fail to indicate command completion\n");
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ret = -EIO;
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goto exit_unlock;
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}
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/*
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* For a read operation, the initiator (BMC) reads the firmware
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* response Command Data Out[31:0] from SBRMI::OutBndMsg_inst[4:1]
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* {SBRMI_x34(MSB):SBRMI_x31(LSB)}.
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*/
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if (msg->read) {
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for (i = 0; i < 4; i++) {
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ret = i2c_smbus_read_byte_data(data->client,
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SBRMI_OUTBNDMSG1 + i);
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if (ret < 0)
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goto exit_unlock;
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msg->data_out |= ret << i * 8;
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}
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}
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/*
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* BMC must write 1'b1 to SBRMI::Status[SwAlertSts] to clear the
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* ALERT to initiator
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*/
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ret = i2c_smbus_write_byte_data(data->client, SBRMI_STATUS,
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sw_status | SW_ALERT_MASK);
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exit_unlock:
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mutex_unlock(&data->lock);
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return ret;
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}
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static int sbrmi_read(struct device *dev, enum hwmon_sensor_types type,
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u32 attr, int channel, long *val)
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{
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struct sbrmi_data *data = dev_get_drvdata(dev);
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struct sbrmi_mailbox_msg msg = { 0 };
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int ret;
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if (type != hwmon_power)
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return -EINVAL;
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msg.read = true;
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switch (attr) {
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case hwmon_power_input:
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msg.cmd = SBRMI_READ_PKG_PWR_CONSUMPTION;
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ret = rmi_mailbox_xfer(data, &msg);
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break;
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case hwmon_power_cap:
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msg.cmd = SBRMI_READ_PKG_PWR_LIMIT;
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ret = rmi_mailbox_xfer(data, &msg);
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break;
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case hwmon_power_cap_max:
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msg.data_out = data->pwr_limit_max;
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ret = 0;
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break;
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default:
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return -EINVAL;
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}
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if (ret < 0)
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return ret;
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/* hwmon power attributes are in microWatt */
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*val = (long)msg.data_out * 1000;
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return ret;
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}
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static int sbrmi_write(struct device *dev, enum hwmon_sensor_types type,
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u32 attr, int channel, long val)
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{
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struct sbrmi_data *data = dev_get_drvdata(dev);
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struct sbrmi_mailbox_msg msg = { 0 };
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if (type != hwmon_power && attr != hwmon_power_cap)
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return -EINVAL;
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/*
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* hwmon power attributes are in microWatt
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* mailbox read/write is in mWatt
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*/
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val /= 1000;
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val = clamp_val(val, SBRMI_PWR_MIN, data->pwr_limit_max);
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msg.cmd = SBRMI_WRITE_PKG_PWR_LIMIT;
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msg.data_in = val;
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msg.read = false;
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return rmi_mailbox_xfer(data, &msg);
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}
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static umode_t sbrmi_is_visible(const void *data,
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enum hwmon_sensor_types type,
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u32 attr, int channel)
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{
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switch (type) {
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case hwmon_power:
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switch (attr) {
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case hwmon_power_input:
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case hwmon_power_cap_max:
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return 0444;
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case hwmon_power_cap:
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return 0644;
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}
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break;
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default:
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break;
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}
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return 0;
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}
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static const struct hwmon_channel_info *sbrmi_info[] = {
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HWMON_CHANNEL_INFO(power,
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HWMON_P_INPUT | HWMON_P_CAP | HWMON_P_CAP_MAX),
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NULL
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};
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static const struct hwmon_ops sbrmi_hwmon_ops = {
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.is_visible = sbrmi_is_visible,
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.read = sbrmi_read,
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.write = sbrmi_write,
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};
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static const struct hwmon_chip_info sbrmi_chip_info = {
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.ops = &sbrmi_hwmon_ops,
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.info = sbrmi_info,
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};
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static int sbrmi_get_max_pwr_limit(struct sbrmi_data *data)
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{
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struct sbrmi_mailbox_msg msg = { 0 };
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int ret;
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msg.cmd = SBRMI_READ_PKG_MAX_PWR_LIMIT;
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msg.read = true;
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ret = rmi_mailbox_xfer(data, &msg);
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if (ret < 0)
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return ret;
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data->pwr_limit_max = msg.data_out;
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return ret;
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}
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static int sbrmi_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct device *dev = &client->dev;
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struct device *hwmon_dev;
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struct sbrmi_data *data;
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int ret;
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data = devm_kzalloc(dev, sizeof(struct sbrmi_data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->client = client;
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mutex_init(&data->lock);
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/* Enable alert for SB-RMI sequence */
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ret = sbrmi_enable_alert(client);
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if (ret < 0)
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return ret;
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/* Cache maximum power limit */
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ret = sbrmi_get_max_pwr_limit(data);
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if (ret < 0)
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return ret;
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hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
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&sbrmi_chip_info, NULL);
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return PTR_ERR_OR_ZERO(hwmon_dev);
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}
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static const struct i2c_device_id sbrmi_id[] = {
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{"sbrmi", 0},
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{}
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};
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MODULE_DEVICE_TABLE(i2c, sbrmi_id);
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static const struct of_device_id __maybe_unused sbrmi_of_match[] = {
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{
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.compatible = "amd,sbrmi",
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},
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{ },
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};
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MODULE_DEVICE_TABLE(of, sbrmi_of_match);
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static struct i2c_driver sbrmi_driver = {
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.class = I2C_CLASS_HWMON,
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.driver = {
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.name = "sbrmi",
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.of_match_table = of_match_ptr(sbrmi_of_match),
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},
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.probe = sbrmi_probe,
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.id_table = sbrmi_id,
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};
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module_i2c_driver(sbrmi_driver);
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MODULE_AUTHOR("Akshay Gupta <akshay.gupta@amd.com>");
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MODULE_DESCRIPTION("Hwmon driver for AMD SB-RMI emulated sensor");
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MODULE_LICENSE("GPL");
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