SCMI

Table of Contents

• Features Supported
• SysConfig Features
• Important Usage Guidelines
• Features NOT Supported
• Example Usage
• API

System Control and Management Interface (SCMI) is a standardized protocol for communication between platform management controllers (Trusted Firmware-A) and application processors. It provides a unified interface for system control and management operations.

Features Supported

• Message-based communication protocol
• Power domain control
• Clock management
• Support for multiple transport protocols
• Protocol versioning

SysConfig Features

• SCMI init and open is done by default through sysconfig generated code.
• SCMI init and open has been done before power and clock are enabled for the peripherals in the sysconfig generated code.

Important Usage Guidelines

• Most of these APIs are already integrated with SysConfig tool and the generated code does the required call to enable a module, set the required clock and so on through the SoC layer.
• User may not need to perform any explicit configuration for power domain and clock, unless it's needed in exceptional scenarios.

Features NOT Supported

NA

Example Usage

Include the below file to access the APIs

#include <drivers/scmi.h>

Base protocol versioning example

    int32_t status;
    uint32_t version;
    SCMI_Handle handle = SCMI_getHandle(CONFIG_SCMI_INSTANCE);
 
    /* Get Power Domain Protocol Version */
    status = SCMI_baseGenericProtocolVersion(handle, SCMI_PROTOCOL_POWER, &version);
    DebugP_log("SCMI_PROTOCOL_POWER: version : %x\r\n", version);
    DebugP_assert(status == SystemP_SUCCESS);
 
    /* Get Clock Domain Protocol Version */
    status = SCMI_baseGenericProtocolVersion(handle, SCMI_PROTOCOL_CLOCK, &version);
    DebugP_log("SCMI_PROTOCOL_CLOCK: version : %x\r\n", version);
    DebugP_assert(status == SystemP_SUCCESS);

Power domain state set and get example

    int32_t status;
    uint32_t flags = 0U;
    /* Power on */
    status = SCMI_powerDomainStateSet(handle, TEST_SCMI_PD_AM62LX_DEV_MMCSD0,
                                      flags, SCMI_PWD_POWER_STATE_ON);
    DebugP_assert(status == SystemP_SUCCESS);
 
    /* Check the power state */
    status = SCMI_powerDomainStateGet(handle, TEST_SCMI_PD_AM62LX_DEV_MMCSD0,
                                      &pstate);
    DebugP_asssert(pstate == SCMI_PWD_POWER_STATE_ON);

Clock rate get and set example

    int32_t status;
    uint64_t clockRate;
    SCMI_Handle handle = SCMI_getHandle(CONFIG_SCMI_INSTANCE);
 
    /* Get clock rate */
    status = SCMI_clockRateGet(handle, TEST_CLK_AM62LX_DEV_FSS0_OSPI0_RCLK_CLK,
                            &clockRate);
    DebugP_assert(status == SystemP_SUCCESS);
    DebugP_log("SCMI_PROTOCOL_CLOCK: TEST_CLK_AM62LX_DEV_FSS0_OSPI0_RCLK_CLK: Get Rate : %d\r\n", clockRate);
 
    /* Set clock rate */
    clockRate = TEST_CLK_AM62LX_CLOCK_FREQ;
    status = SCMI_clockRateSet(handle, TEST_CLK_AM62LX_DEV_FSS0_OSPI0_RCLK_CLK,
                            clockRate);
    DebugP_assert(status == SystemP_SUCCESS);

API

APIs for SCMI