Power Mode User Guide

Note

SL2610 Power Modes are implemented in the M52 firmware and are currently released as a binary. This guide applies to SL1620, SL1640, and SL1680.

Overview

Astra Machina supports two types of power modes, as follows.

Suspend Mode
- System state is stored in RAM
- Most hardware is powered off except RAM and the AON domain
- Can resume very fast
Low Power Mode
- System is fully turned off
- Only AON domain is alive

	Suspend Mode	Low Power Mode
SL1620	✔	✖
SL1640	✔	✔
SL1680	✔	✔
SL261x	✔	✔

Power Flow

The commands below are used to enter power flow.

Suspend

“systemctl suspend” or “echo mem > /sys/power/state”
Low Power

“shutdown -h now”

The following diagrams show the power flow of Astra platforms.

Suspend and Resume

Note

Under Suspend mode of SL1620, VCPU domain remains alive and primary CPU is in WFI state while other CPUs are powered off.

Note

The System Manager of SL1640/SL1680 is limited to access the resources of SoC power domain.

Note

The System Manager on SL261x has full access permission to SoC side.

Low Power and Boot-Up

SL1620 does not support Low Power mode because it does not include System Manager on SL1620.

The boot-up from Low Power mode is almost the same as cold boot.

Configurations and Settings

To support power mode, each module needs to set the appropriate configurations.

Linux Kernel Configurations

Linux Kernel 6.12 as an example, below options are needed to enable the power mode.

Core Power Management (MANDATORY)
- CONFIG_PM=y
- CONFIG_PM_SLEEP=y
- CONFIG_SUSPEND=y
- CONFIG_SUSPEND_FREEZER=y
ARM64 Architecture Support
- CONFIG_ARM64=y
- CONFIG_ARCH_SUSPEND_POSSIBLE=y
- CONFIG_ARCH_SUSPEND_NONZERO_CPU=y
PSCI
- CONFIG_ARM_PSCI_FW=y
- CONFIG_ARM_PSCI_CPUIDLE=y
- CONFIG_ARM_PSCI_CPUIDLE_DOMAIN=y
CPU Idle Framework
- CONFIG_CPU_IDLE=y
- CONFIG_CPU_IDLE_MULTIPLE_DRIVERS=y
- CONFIG_DT_IDLE_STATES=y
Device Tree Support
- CONFIG_OF=y
- CONFIG_OF_SLEEP=y

Here is the power mode behavior on ARM64 defined in device tree.

psci {
    compatible = "arm,psci-1.0";
    method = "smc";
};

cpus {
    cpu@0 {
        enable-method = "psci";
    };
};

idle-states {
    entry-method = "psci";
};

ATF (Arm Trusted Firmware)

Both Suspend-to-RAM and Low Power require the cooperation of Arm Trusted Firmware.

PSCI version >= 1.0 is recommended.

The version of ATF in ASTRA release 2.3.0 is v2.7.0. It supports PSCI version 1.1.

DEN0022C_Power_State_Coordination_Interface.pdf

Implement vendor specific PSCI operations.

To support power modes, ASTRA Machina implements below functions.

const plat_psci_ops_t berlin_plat_psci_ops = {
    .cpu_standby         = berlin_cpu_standby,
    .pwr_domain_on           = berlin_pwr_domain_on,
    .pwr_domain_off          = berlin_pwr_domain_off,
    .pwr_domain_suspend      = berlin_pwr_domain_suspend,
    .pwr_domain_on_finish        = berlin_pwr_domain_on_finish,
    .pwr_domain_suspend_finish   = berlin_pwr_domain_suspend_finish,
    .pwr_domain_pwr_down_wfi = berlin_pwr_domain_pwr_down_wfi,
    .system_off          = berlin_system_off,
    .system_reset            = berlin_system_reset,
    .system_reset2           = berlin_system_reset2,
    .validate_power_state        = berlin_validate_power_state,
    .validate_ns_entrypoint      = berlin_validate_ns_entrypoint,
    .get_sys_suspend_power_state = berlin_get_sys_suspend_power_state,
};

System Manager

The System Manager resides in the AON domain and it is responsible for the power management of SoC. It uses GPIO or PMIC to control the on/off of power.

Table of Power Control

Power Domain	SL1640	SL1680	SL261x
VCORE	EXPANDE R.SM-TW3.GPIO0_0	EXPANDE R.SM-TW3.GPIO0_0	S Y8827N.SM_TW2.0x60
VCPU	EXPANDE R.SM-TW3.GPIO0_0	EXPANDE R.SM-TW3.GPIO0_1	✖
VDDM	EXPANDE R.SM-TW3.GPIO0_2	EXPANDE R.SM-TW3.GPIO0_2	EXP.SM-TW0.GPIO0_2
V DDM_LPQ	EXPANDE R.SM-TW3.GPIO0_3	EXPANDE R.SM-TW3.GPIO0_3	EXP.SM-TW0.GPIO0_3
Stan d-By_En	EXPANDE R.SM-TW3.GPIO0_4	EXPANDE R.SM-TW3.GPIO0_4	EXP.SM-TW0.GPIO0_4
NPU	Not Control by SM	Not Control by SM	Reg.R A_Gbl_npu_pwr_ctrl
GPU	Not Control by SM	Not Control by SM	Reg.RA_ Gbl_gfx3D_pwr_ctrl

Power Measurement

This section focuses on power measurement in Suspend and Low Power modes.

To quick check if the power domain is powered off or on, Astra Machina platforms provides short and voltage check points. Please refer to the part of “Short and voltage check points” in Astra Machina Eval Platform.

Here shows the diagram of SL261x.

To get the accurate power data, please use Power Meter.

For SL261x, software provides a way to calculate the power under Suspend and Low Power. Here are the steps.

“systemctl suspend” or “echo mem > /sys/power/state” to suspend
Wait for about 10 second
Press ‘p’

Example output:

0356393760:[0][INF][SYS ]:System Power status (100 samples)

0356396764:[0][INF][GENR]: PWR_3V3 PWR_1V8 VCORE_SOC VDDM_1V2 VDDM_2V5 VCORE_SM Total Power

0356396764:[0][INF][GENR]: 134.27 31.85 0.00 24.16 10.02 19.65 219.95(mW)

By the way, Kernel also implement a feature to measure power at runtime. Power Measurements with Astra Machina

Wake-Up

Wake Up Source

ASTRA Machina supports several wake up sources relies on the design of the board. Here lists several possible sources.

UART

UART wake up is enabled by default and the wake up keys are ‘W’, ‘w’ and space.

CEC

CEC wake up is supported in Android case. Here lists the wake events.

CEC_MSG_OPCODE_IMAGE_VIEW_ON
CEC_MSG_OPCODE_TEXT_VIEW_ON
CEC_MSG_OPCODE_USER_CONTROL_PRESSED
CEC_MSG_OPCODE_ACTIVE_SOURCE
CEC_MSG_OPCODE_SET_STREAM_PATH
CEC_VEND_CMD_BUDDY_LAUNCH_SPECIFIC_APP
CEC_MSG_OPCODE_DECK_CONTROL

WOL

On SL1640, it use a built-in 10/100 FE-PHY. An interrupt will be triggered and send to Cortex CM3 NVIC controller. System Manager will receive and handle the event and boot SoC.

For Geth, if WOL package is received, it will toggle a SM GPIO. System Manager shall handle the GPIO signal and wake up SoC.

WIFI

The wake up signal of WIFI is also connected to a SM GPIO.

BT

BT uses the same way as WIFI. Toggling a GPIO to inform System Manager.

Note

Due to lack available GPIOs, Geth/WIFI/BT may share one or two GPIOs. To distinguish different wake up source, the different waveform is required. For BT, it also requires to distinguish Netflix key and other keys per Android’s demand.

Here is a possible implementation.

Wake Up Configuration

SL1620

CPU state is WFI on SL1620 Suspend Mode. Interrupt events are needed to wake up the system. It can be set by a SMCCC in u-boot or Linux.

Here is the example of u-boot.

#define SYNA_SIP_SMC32_WAKEUP_CONFIG    0x82000002
#define SYNA_SIP_SMC64_WAKEUP_CONFIG    0xC2000002

unsigned long call_syna_sip(unsigned long id, unsigned long reg0, unsigned long reg1, unsigned long reg2)
{
    struct pt_regs regs;
    regs.regs[0] = id;
    regs.regs[1] = reg0;
    regs.regs[2] = reg1;
    regs.regs[3] = reg2;

    smc_call(&regs);

    return regs.regs[0];
}

call_syna_sip(SYNA_SIP_SMC64_WAKEUP_CONFIG, CONFIG_SYS_WAKEUP_INTR1, 0, 0);
call_syna_sip(SYNA_SIP_SMC64_WAKEUP_CONFIG, CONFIG_SYS_WAKEUP_INTR2, 0, 0);

SL1640/SL1680

WOL (only available on SL1640)

Add “CFLAGS += -DWOLENABLE” in platform.mk.
CEC

Set CONFIG_SM_CEC=y in the profile of a project.

GPIO
Geth, WIFI/BT wake up are all implemented through GPIO.
Set GPIO mode in the Linux Kernel dolphin-rdk.dts in the linux-syna package.
https://github.com/synaptics-astra/linux_6_12-main/blob/scarthgap_6.12_v2.4.0/arch/arm64/boot/dts/synaptics/dolphin-rdk.dts

eth_phy_pmux: eth_phy-pmux {
   groups = "SM_TDI";
   function = "gpio";
};

An example of SL1680.

The configuration can be added to the platform_customization.c in the synasdk-sm package. https://github.com/synaptics-astra/boot/blob/scarthgap_6.12_v2.4.0/bootloader/sm_cm3/syna/customization/dolphin/dolphin-rdk/platform_customization.c

This example is for dolphin (SL1680). Use platypus for SL1640.

DECLARE_GPIO_ISR(SM_GPIO_PORT_WIFIBT, EDGE_SENSITIVE, FALLING_EDGE, sm_gpio_isr);
#ifndef WIFIBT_GAP_MIN
#define WIFIBT_GAP_MIN  10
#define WIFIBT_GAP_MAX  125
#define ETH_GAP_MAX     512
#endif

#ifndef BTKEY_NETFLIX_GAP_MIN
#define BTKEY_NETFLIX_GAP_MIN 395
#define BTKEY_NETFLIX_GAP_MAX 415
#endif

/* wifi */
DECLARE_GPIO_WAKEUP(wifi, SM_GPIO_PORT_WIFIBT, 0, (WIFIBT_GAP_MIN *2), MV_SM_WAKEUP_SOURCE_WIFI, 0, 0);

/* bt (not netflix key) */
DECLARE_GPIO_WAKEUP(bt_otherkey, SM_GPIO_PORT_WIFIBT, (WIFIBT_GAP_MIN *2), BTKEY_NETFLIX_GAP_MIN, MV_SM_WAKEUP_SOURCE_BT, 1, KEY_OTHERS);

/* bt (netflix key) */
DECLARE_GPIO_WAKEUP(bt_netflixkey, SM_GPIO_PORT_WIFIBT, BTKEY_NETFLIX_GAP_MIN, BTKEY_NETFLIX_GAP_MAX, MV_SM_WAKEUP_SOURCE_BT, 1, KEY_NETFLIX);

/* geth */
DECLARE_GPIO_WAKEUP(geth, SM_GPIO_PORT_GEPHY, BTKEY_NETFLIX_GAP_MAX, DEFAULT_THOLD, MV_SM_WAKEUP_SOURCE_WOL, 0, 0);