K230 Power Consumption Management Adaptation Guide

Preface

Overview

This document mainly describes the K230 platform power consumption management framework and how to use power control.

Target Audience

This document (this guide) is mainly applicable to the following personnel:

• Technical Support Engineers

• Software Development Engineers

Abbreviation Definitions

Abbreviation	Description

Revision History

Document Version	Modification Description	Modifier	Date
V1.0	Initial version	Zhang Tao	2023/07/17

1. Overview

The K230 platform power consumption management framework is divided into large core power management and small core power management, with both cores being independently controlled. The large core (rt-smart) mainly controls CPU1, AI module, display module, multimedia module, etc., while the small core (linux) mainly controls CPU0, etc. After the chip is powered on, all power domains and clocks are enabled by default. To reduce power consumption, the following power domains and clocks are turned off during the uboot-spl stage:

1. KPU power, KPU clk, KPU aclk

2. VPU power, VPU clk, VPU aclk, VPU cfgclk

3. DPU power, DPU clk, DPU aclk, DPU pclk

4. DISP power, disp clk

5. mclk

At the same time, each device driver is responsible for the corresponding clock and power domain management. When the user turns on the device, the driver should turn on the power domain and clock. When the user turns off the device, the driver should turn off the clock and power domain. For devices that do not support power domain management, only clock control is required.

2. Large Core Power Control

2.1 Control Framework Introduction

2.1.1 Power Management Domains

Large core power control mainly revolves around several power management domains:

1. CPU1

2. KPU

3. DPU

4. VPU

5. DISP

Each power management domain can be set to different frequencies. Among them, CPU1 and KPU also support DVFS, while other power management domains only support frequency settings. The frequencies supported by power management domains are built into the driver, and users can modify them according to their actual scenarios.

2.1.2 Control Strategies

Each power management domain can be set with different power control strategies, divided into four strategies:

1. Manual mode, where the user can manually configure the frequency by calling the interface in the program.

2. Performance mode, locking the highest frequency.

3. Power-saving mode, locking the lowest frequency.

4. Automatic mode, automatically switching frequencies based on load (only supported by CPU1).

2.1.3 Thermal Protection

Power control supports two levels of thermal protection. The first level limits the frequency of the module when the specified temperature is exceeded, and the second level forcibly shuts down the power domain of the module when the specified temperature is exceeded. Both levels support user configuration.

2.1.4 Power and Clock

Power control supports manual power on/off and clock control for each power management domain. Users generally do not need to manually call these; the device driver will turn on the power and clock when using the device and turn off the power and clock when turning off the device.

2.1.5 CPU1

The CPU supports four strategies: Manual Mode, Performance Mode, Power-saving Mode, Automatic Mode.

For the current power consumption optimization of CPU1 in door lock and dictionary pen POC, the main approach is to use manual mode. Users set a high frequency before the program segment with heavy computation and set it to a low frequency after completion. For multi-process or multi-threaded applications, each application can lock the minimum operating frequency. You can adjust the application to achieve the best power consumption by viewing the CPU statistics.

2.1.6 KPU

The KPU supports three strategies: Manual Mode, Performance Mode, Power-saving Mode.

KPU power control mainly adjusts the KPU frequency and switches the power clock. Through nncase, the kd_mpi_pm_runtime_runstage interface is called to inform the current running stage of the KPU. Users can control the clocks and power of each module according to each stage. For example, when using KPU in AI, the KPU clock can be turned on, and the clock can be turned off immediately after use (the control of the AI2D clock is automatically controlled by hardware by default). Users can also manually set the KPU frequency according to actual scenarios, such as setting the maximum frequency for high frame rate requirements and setting a lower frequency to reduce power consumption if there are no frame rate requirements or if the requirements are met.

2.1.7 DPU

Refer to KPU.

2.1.8 VPU

Refer to KPU.

2.1.9 DISPLAY

For the display-related part, several frequency combinations are built in, such as 60fps, 30fps, etc. Set them according to different scenarios at startup. Frequency adjustment during operation is not supported, only clock and power domain shutdown are supported.

2.2 Usage

The power management framework is enabled by default, with all domains initially set to Manual Mode, and the frequency is the system default initial value, which does not affect the original system functions.

2.2.1 Using Manual Mode

Users can refer to the following process to use Manual Mode:

1. Use the kd_mpi_pm_get_profiles interface to get the supported frequency points of the power management domain.

2. Use the kd_mpi_pm_set_governor interface to set the management strategy of the power management domain to manual mode.

3. Use the kd_mpi_pm_set_profile or kd_mpi_pm_set_profile_lock interface to set the profile number of the power management domain.

2.2.2 Using Other Modes

Users can refer to the following process to use Performance Mode, Power-saving Mode, Automatic Mode:

1. Use the kd_mpi_pm_set_governor interface to set the management strategy of the power management domain to the corresponding mode.

2.2.3 Using Thermal Protection

1. Use the kd_mpi_pm_set_thermal_protect interface to set the thermal protection temperature and downclock profile number. When the temperature exceeds the specified value, it will downclock to the specified profile.

2. Use the kd_mpi_pm_set_thermal_shutdown interface to set the thermal shutdown temperature. When the temperature exceeds the specified value, each power management domain will be forcibly powered off.

2.2.4 Using Custom Frequencies

For example, if you need to modify the frequencies supported by the CPU, you can modify the profiles array in the k230_sdk/src/big/mpp/kernel/pm/src/pm_domain_cpu.c file:

static k_pm_profile profiles[] = {
    {1.6e9, 0.8e6},
    {1.188e9, 0.7e6},
    {0.8e9, 0.68e6},
    {0.594e9, 0.66e6},
    {0.4e9, 0.64e6},
    {0.2e9, 0.62e6},
};

After modifying the array, you also need to modify the set_clock function in the same file to generate the corresponding frequency. If the domain supports DVFS, you also need to specify the voltage corresponding to each frequency. If not supported, use the default voltage uniformly.

Modifications for KPU, DPU, and VPU are similar.

Note: If you need to use the CPU Automatic Mode strategy, after modifying the frequency, you also need to modify the load conversion table load_table.

2.3 API Reference

The framework provides the following APIs:

• kd_mpi_pm_set_reg

• kd_mpi_pm_get_reg

• kd_mpi_pm_get_profiles

• kd_mpi_pm_get_stat

• kd_mpi_pm_set_governor

• kd_mpi_pm_get_governor

• kd_mpi_pm_set_profile

• kd_mpi_pm_get_profile

• kd_mpi_pm_set_profile_lock

• kd_mpi_pm_set_profile_unlock

• kd_mpi_pm_set_thermal_protect

• kd_mpi_pm_get_thermal_protect

• kd_mpi_pm_set_thermal_shutdown

• kd_mpi_pm_get_thermal_shutdown

• kd_mpi_pm_set_clock

• kd_mpi_pm_set_power

• kd_mpi_pm_runtime_runstage

2.3.1 kd_mpi_pm_set_reg

【Description】

Write to the register, used for extension or debugging.

【Syntax】

int kd_mpi_pm_set_reg(uint32_t reg, uint32_t val);

【Parameters】

Parameter Name	Description	Input/Output
reg	Register address	Input
val	Register data	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

Only supports CMU, PWR address segments.

【Example】

None

2.3.2 kd_mpi_pm_get_reg

【Description】

Read the register, used for extension or debugging.

【Syntax】

int kd_mpi_pm_get_reg(uint32_t reg, uint32_t *pval);

【Parameters】

Parameter Name	Description	Input/Output
reg	Register address	Input
pval	Register data	Output

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

Only supports CMU, PWR address segments.

【Example】

None

2.3.3 kd_mpi_pm_get_profiles

【Description】

Get the profile attributes of the power management domain.

【Syntax】

int kd_mpi_pm_get_profiles(k_pm_domain domain, uint32_t *pcount, k_pm_profile *pprofile);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
pcount	Number of attributes	Input/Output
pprofile	Attributes	Output

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

1. *pcount maximum value is 128.

2. When *pcount is 0, it returns the number of profiles in the power management domain, pprofile is not used.

3. When *pcount is greater than 0 and less than a certain value, it returns the specified number of profile attributes, pprofile cannot be null and must be larger than *pcount.

4. When *pcount is greater than a certain value, it returns the maximum number of profiles and the maximum number of profile attributes, pprofile cannot be null and must be larger than the maximum value of *pcount.

5. Profiles are arranged in descending order, with index 0 being the highest frequency, and the larger the index, the lower the frequency.

【Example】

None

2.3.4 kd_mpi_pm_get_stat

【Description】

Get the statistical information of the power management domain.

【Syntax】

int kd_mpi_pm_get_stat(k_pm_domain domain);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

1. Currently, only the CPU power management domain is supported.

【Example】

None

2.3.5 kd_mpi_pm_set_governor

【Description】

Set the management strategy of the power management domain.

【Syntax】

int kd_mpi_pm_set_governor(k_pm_domain domain, k_pm_governor governor);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
governor	Management strategy	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

None

【Example】

None

2.3.6 kd_mpi_pm_get_governor

【Description】

Get the management strategy of the power management domain.

【Syntax】

int kd_mpi_pm_get_governor(k_pm_domain domain, k_pm_governor *pgovernor);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
pgovernor	Management strategy	Output

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

None

【Example】

None

2.3.7 kd_mpi_pm_set_profile

【Description】

Set the current profile index of the power management domain.

【Syntax】

int kd_mpi_pm_set_profile(k_pm_domain domain, int32_t index);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
index	Profile index	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

1. Only supports manual mode.

2. Supports negative numbers, e.g., -1 represents the last profile, -2 represents the second last profile.

3. Negative numbers out of range will be limited to the first profile.

4. Positive numbers out of range will be limited to the last profile.

【Example】

None

2.3.8 kd_mpi_pm_get_profile

【Description】

Get the current profile index of the power management domain.

【Syntax】

int kd_mpi_pm_get_profile(k_pm_domain domain, int32_t *pindex);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
pindex	Profile index	Output

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

None

【Example】

None

2.3.9 kd_mpi_pm_set_profile_lock

【Description】

Set the minimum profile index of the power management domain.

【Syntax】

int kd_mpi_pm_set_profile_lock(k_pm_domain domain, int32_t index);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
index	Profile index	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

1. After setting, the current profile may be greater than the set value. For example, if another process sets the minimum profile to 1, and the current process sets the minimum profile to 2, the actual profile will be 1.

2. Refer to kd_mpi_pm_set_profile for other details.

【Example】

None

2.3.10 kd_mpi_pm_set_profile_unlock

【Description】

Clear the minimum profile index of the power management domain.

【Syntax】

int kd_mpi_pm_set_profile_unlock(k_pm_domain domain, int32_t index);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
index	Profile index	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

None

【Example】

None

2.3.11 kd_mpi_pm_set_thermal_protect

【Description】

Set the thermal protection downclocking for the power management domain.

【Syntax】

int kd_mpi_pm_set_thermal_protect(k_pm_domain domain, int32_t temp, int32_t index);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
temp	Temperature, unit: 0.01℃	Input
index	Profile index	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

1. Only CPU and KPU power management domains support thermal protection settings.

【Example】

None

2.3.12 kd_mpi_pm_get_thermal_protect

【Description】

Get the thermal protection downclocking configuration of the power management domain.

【Syntax】

int kd_mpi_pm_get_thermal_protect(k_pm_domain domain, int32_t *ptemp, int32_t *pindex);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
ptemp	Temperature, unit: 0.01℃	Output
pindex	Profile index	Output

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

1. Only CPU and KPU power management domains support thermal protection settings.

【Example】

None

2.3.13 kd_mpi_pm_set_thermal_shutdown

【Description】

Set the thermal shutdown temperature.

【Syntax】

int kd_mpi_pm_set_thermal_shutdown(int32_t temp);

【Parameters】

Parameter Name	Description	Input/Output
temp	Temperature, unit: 0.01℃	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

None

【Example】

None

2.3.14 kd_mpi_pm_get_thermal_shutdown

【Description】

Get the thermal shutdown temperature.

【Syntax】

int kd_mpi_pm_get_thermal_shutdown(int32_t *ptemp);

【Parameters】

Parameter Name	Description	Input/Output
ptemp	Temperature, unit: 0.01℃	Output

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

None

【Example】

None

2.3.15 kd_mpi_pm_set_clock

【Description】

Set the clock of the power management domain.

【Syntax】

int kd_mpi_pm_set_clock(k_pm_domain domain, bool enable);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
enable	Enable/Disable	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

None

【Example】

None

2.3.16 kd_mpi_pm_set_power

【Description】

Set the power of the power management domain.

【Syntax】

int kd_mpi_pm_set_power(k_pm_domain domain, bool enable);

【Parameters】

Parameter Name	Description	Input/Output
domain	Power management domain	Input
enable	Enable/Disable	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

None

【Example】

None

2.3.17 kd_mpi_pm_runtime_runstage

【Description】

Set the runtime stage for nncase, called by nncase runtime.

【Syntax】

int kd_mpi_pm_runtime_runstage(k_runtimestage_id stage);

【Parameters】

Parameter Name	Description	Input/Output
stage	Runtime stage ID	Input

【Return Value】

Return Value	Description
0	Success
Non-zero	Failure, see Error Codes for its value

【Requirements】

• Header file: mpi_pm_api.h

• Library file: libpm.a

【Note】

1. The PM module has a built-in control strategy. It turns on the KPU power and clock at RUNTIMESTAGE_ID_KPU_START, and turns off the KPU power and clock at RUNTIMESTAGE_ID_KPU_STOP. Users can override this function according to their actual needs.

【Example】

None

2.4 Data Structures

2.4.1 k_pm_domain

【Description】

Define power management domains.

【Definition】

typedef enum {
    PM_DOMAIN_CPU,
    PM_DOMAIN_KPU,
    PM_DOMAIN_DPU,
    PM_DOMAIN_VPU,
    PM_DOMAIN_DISPLAY,
    PM_DOMAIN_MEDIA,
    PM_DOMAIN_NR,
} k_pm_domain;

【Members】

Member Name	Description
PM_DOMAIN_CPU	CPU power management domain
PM_DOMAIN_KPU	KPU power management domain
PM_DOMAIN_DPU	DPU power management domain
PM_DOMAIN_VPU	VPU power management domain
PM_DOMAIN_DISPLAY	Display power management domain
PM_DOMAIN_MEDIA	Media power management domain
PM_DOMAIN_NR	Total number of power management domains

【Notes】

None

2.4.2 k_pm_governor

【Description】

Define power management strategies.

【Definition】

typedef enum {
    PM_GOVERNOR_MANUAL,
    PM_GOVERNOR_PERFORMANCE,
    PM_GOVERNOR_ENERGYSAVING,
    PM_GOVERNOR_AUTO,
} k_pm_governor;

【Members】

Member Name	Description
PM_GOVERNOR_MANUAL	Manual mode
PM_GOVERNOR_PERFORMANCE	Performance mode
PM_GOVERNOR_ENERGYSAVING	Energy-saving mode
PM_GOVERNOR_AUTO	Automatic mode

【Notes】

None

2.4.3 k_pm_profile

【Description】

Define frequency points, including frequency and voltage.

【Definition】

typedef struct {
    int32_t freq;
    int32_t volt;
} k_pm_profile;

【Members】

Member Name	Description
freq	Frequency, unit: Hz
volt	Voltage, unit: uV

【Notes】

1. Frequency points are arranged in descending order, with index 0 being the highest frequency, and the larger the index, the lower the frequency.

2.4.4 k_runtimestage_id

【Description】

Define AI runtime stages, which may involve AI2D, KPU, CPU during AI operation.

【Definition】

typedef enum {
    RUNTIMESTAGE_ID_AI2D_START,
    RUNTIMESTAGE_ID_AI2D_STOP,
    RUNTIMESTAGE_ID_KPU_START,
    RUNTIMESTAGE_ID_KPU_STOP,
    RUNTIMESTAGE_ID_CPU_START,
    RUNTIMESTAGE_ID_CPU_STOP,
} k_runtimestage_id;

【Members】

Member Name	Description
RUNTIMESTAGE_ID_AI2D_START	AI2D operation start
RUNTIMESTAGE_ID_AI2D_STOP	AI2D operation stop
RUNTIMESTAGE_ID_KPU_START	KPU operation start
RUNTIMESTAGE_ID_KPU_STOP	KPU operation stop
RUNTIMESTAGE_ID_CPU_START	CPU operation start
RUNTIMESTAGE_ID_CPU_STOP	CPU operation stop

【Notes】

None

2.5 Error Codes

Error Code	Macro Definition	Description
0xa0178003	K_ERR_PM_ILLEGAL_PARAM	Invalid parameter setting
0xa0178004	K_ERR_PM_EXIST	Device already exists
0xa0178005	K_ERR_PM_UNEXIST	Device does not exist
0xa0178006	K_ERR_PM_NULL_PTR	Null pointer parameter
0xa0178007	K_ERR_PM_NOT_CONFIG	Device not configured
0xa0178008	K_ERR_PM_NOT_SUPPORT	Operation not supported
0xa0178009	K_ERR_PM_NOT_PERM	Operation not permitted
0xa017800c	K_ERR_PM_NOMEM	Memory allocation failed
0xa0178010	K_ERR_PM_NOTREADY	Device not ready
0xa0178011	K_ERR_PM_BADADDR	Bad address
0xa0178012	K_ERR_PM_BUSY	Device busy

3. Low-Power Core Control

3.1 Control Framework Introduction

The low-power core control mainly targets CPU0, supporting Linux cpu_freq, temperature protection, and cooling control.

3.1.1 cpu_freq

cpu_freq is a Linux standard. Please refer to the kernel documentation.