WHC Wi-Fi Low Power

WHC Low Power Introduction

When the Host is idle, power consumption can be reduced via standby mode. The core interaction flow is shown below:

The interaction between Device and Host in low-power mode consists of the following three parts:

Device Wowlan Cmd

Host can trigger Device to enter low-power state via interrupts or messages through CUST_PATH:

Trigger Type	Interface	Description
CUST_PATH	ALL	Sends customized commands via CUST_PATH
RPWM INT	SDIO	Triggered by SDIO-specific interrupt
Other INT	ALL	Uses GPIO general external interrupt (high compatibility)

CUST_PATH

For implementation, refer to the tickps command in the Cust Path demo.

RPWM INT

Ameba SDK automatically triggers RPWM interrupt during host suspend to notify Device to enter low-power mode.

Implementation function: whc_sdio_host_rpwm_notify.

../../_images/fullmac_powersave_sleeprpwm.svg

Other INT

For other interrupts (e.g., GPIO), refer to RPWM INT.

Host Wakes Device

Host selects interrupt type based on Device’s low-power mode (CG/PG):

../../_images/fullmac_powersave_hostwakedev.svg

Interrupt	Device State	Interface	Description
CUST_PATH	Active	None	CUST_PATH only responds when Device is Active
RPWM INT	CG	SDIO	Triggers RPWM interrupt via SDIO-specific signal
Other INT	CG/PG	ALL	Uses GPIO or other interrupts

RPWM INT

Ameba SDK automatically triggers RPWM interrupt during host resume to wake Device from CG state.

Implementation function: whc_sdio_host_rpwm_notify.

../../_images/fullmac_powersave_wakeprpwm.svg

Other INT

For other interrupts (e.g., GPIO), refer to: RPWM INT

Device Wakes Host

Device wakes Host via interrupts, with methods depending on Host hardware support:

../../_images/fullmac_powersave_devwakehost.svg

Interrupt	Description
SDIO INT	Standard packet trigger (no additional code adaptation required)
Other INT	Uses GPIO or other interrupts (high compatibility)

WHC Low Power API

API Header Files

whc_host_linux/app/whc_host_app_api.h

component/whc/whc_dev/whc_dev_powersave.h

API Reference

whc_host_set_ps_cmd

void whc_host_set_ps_cmd(struct whc_dev_ps_cmd *pcmd, char *cmd_arg)
{
   if (strcmp(cmd_arg, "r") == 0) {
      pcmd->type = WHC_CMD_TICKPS_R;
   } else if (strcmp(cmd_arg, "a") == 0) {
      pcmd->type = WHC_CMD_TICKPS_A;
   } else if (strcmp(cmd_arg, "cg") == 0) {
      pcmd->type = WHC_CMD_TICKPS_TYPE_CG;
   } else if (strcmp(cmd_arg, "pg") == 0) {
      pcmd->type = WHC_CMD_TICKPS_TYPE_PG;
   }

   return;
}

Item	Description
Function	Parses user input and fills the low-power command structure
Parameters	pcmd: Pointer to the command structure cmd_arg: Input string
Return	None

whc_dev_tickps_cmd

void whc_dev_tickps_cmd(struct whc_dev_ps_cmd *ps_cmd)
{
   uint8_t subtype = ps_cmd->type;
   whc_dev_ps_set_tickps_cmd(subtype);

   return;
}

Item	Description
Function	Parses the host command field whc_dev_ps_cmd
Parameters	ps_cmd: Command structure containing the type
Return	None

whc_dev_ps_set_tickps_cmd

void whc_dev_ps_set_tickps_cmd(u8 subtype)
{
   if (subtype == WHC_CMD_TICKPS_R) {
      /* dev enter low power mode after release lock */
      pmu_release_wakelock(PMU_OS);
      pmu_release_wakelock(PMU_WHC_WIFI);
   } else if (subtype == WHC_CMD_TICKPS_A) {
      pmu_acquire_wakelock(PMU_OS);
      pmu_acquire_wakelock(PMU_WHC_WIFI);
   } else if (subtype == WHC_CMD_TICKPS_TYPE_PG) {
      /* set sleep type to pg */
      pmu_set_sleep_type(SLEEP_PG);
   } else if (subtype == WHC_CMD_TICKPS_TYPE_CG) {
      /* set sleep type to cg */
      pmu_set_sleep_type(SLEEP_CG);
   }

Item	Description
Function	Configures PMU low-power states based on host commands
Parameters	subtype: Host command type
Return	None

whc_dev_ps_resume_cb

void whc_dev_ps_resume_cb(void)
{
   /* acquire wakelock to prevent dev enter low power mode */
   whc_dev_ps_set_tickps_cmd(WHC_CMD_TICKPS_A);
#if defined (CONFIG_FW_DRIVER_COEXIST) && CONFIG_FW_DRIVER_COEXIST
   extern void wifi_hal_system_resume_wlan(void);
   /* resume wlan */
   wifi_hal_system_resume_wlan();
#endif
}

Item	Description
Function	Device-side resume callback after wakeup
Parameters	None
Return	None

WHC Low Power Operation Flow

Configure the device’s sleep type, referring to the tickps command in the Cust Path demo.
Identify wireless physical interface (find phy field): rfkill list.
Enable any-packet wakeup: sudo iw phy <phyname> wowlan enable any (replace actual phyname).
Verify WoWLAN configuration: sudo iw phy wowlan show.
Initiate system suspend echo mem | sudo tee /sys/power/state.

Note

phyname may change to phy1/phyN after rmmod, re-validate steps 1-3 after module reload.

Configure the device’s sleep type, referring to tickps command in the Cust Path demo.
Pre-set wakeup triggers on the device side, for example: receiving IPv4/IPv6 packets on specific ports (with TCP/IP on Device-side filtering support), or triggering GPIO interrupts (hardware-level wakeup mechanism).
Notify the device of the host’s impending low-power mode transition, referring to setrdy command in the Cust Path demo.
The host safely enters low-power mode.

Programming Guide for Ameba as WHC Host

Configure the device’s sleep type, referring to tickps command in the Cust Path demo.
Configure the sleep type of Host, referring to command AT+TICKPS in AT Command.
Preset wake-up triggers on the device side.
Notify the device of the host’s impending low-power mode transition, referring to setrdy command in the Cust Path demo.
The host safely enters low-power mode.

Note

For other RTOS Host platforms, please contact us.