drivers: wifi: siwx91x: Add support for set_power_save()

Added power-save mode support to optimize station wake-up timing
and reduce power consumption. The device currently supports
only legacy power-save mode.

This feature can be tested using the Wifi shell:
  - ps: Enable the PS. By default, the device operates in fast
        PSP mode.
  - ps_exit_strategy: Updates mode if enabled; otherwise, follows
        the configured exit strategy when power-save is enabled.
  - ps_wakeup_mode: Configures the wake-up behavior.
  - ps_timeout: Defines the timeout duration for power-save mode.

Co-authored-by: Arunmani Alagarsamy <arunmani.a@silabs.com>
Signed-off-by: Arunmani Alagarsamy <arunmani.a@silabs.com>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>

drivers/wifi/siwx91x/siwx91x_wifi.c

@@ -253,6 +253,139 @@ static enum wifi_mfp_options siwx91x_set_sta_mfp_option(sl_wifi_security_t secur
 	return WIFI_MFP_UNKNOWN;
 }
 
+static int siwx91x_get_connected_ap_beacon_interval_ms(void)
+{
+	sl_wifi_operational_statistics_t sl_stat;
+	sl_wifi_interface_t interface;
+	int status;
+
+	interface = sl_wifi_get_default_interface();
+	if (FIELD_GET(SIWX91X_INTERFACE_MASK, interface) != SL_WIFI_CLIENT_INTERFACE) {
+		return 0;
+	}
+
+	status = sl_wifi_get_operational_statistics(SL_WIFI_CLIENT_INTERFACE, &sl_stat);
+	if (status) {
+		return 0;
+	}
+
+	return sys_get_le16(sl_stat.beacon_interval) * 1024 / 1000;
+}
+
+static int siwx91x_apply_power_save(struct siwx91x_dev *sidev)
+{
+	sl_wifi_performance_profile_t sl_ps_profile;
+	sl_wifi_interface_t interface;
+	int beacon_interval;
+	int status;
+
+	interface = sl_wifi_get_default_interface();
+	if (FIELD_GET(SIWX91X_INTERFACE_MASK, interface) != SL_WIFI_CLIENT_INTERFACE) {
+		return 0;
+	}
+
+	if (sidev->state == WIFI_STATE_INTERFACE_DISABLED) {
+		return 0;
+	}
+
+	sl_wifi_get_performance_profile(&sl_ps_profile);
+
+	if (sidev->ps_params.enabled == WIFI_PS_DISABLED) {
+		sl_ps_profile.profile = HIGH_PERFORMANCE;
+		goto out;
+	}
+	if (sidev->ps_params.exit_strategy == WIFI_PS_EXIT_EVERY_TIM) {
+		sl_ps_profile.profile = ASSOCIATED_POWER_SAVE_LOW_LATENCY;
+	} else if (sidev->ps_params.exit_strategy == WIFI_PS_EXIT_CUSTOM_ALGO) {
+		sl_ps_profile.profile = ASSOCIATED_POWER_SAVE;
+	} else {
+		/* Already sanitized by siwx91x_set_power_save() */
+		return -EINVAL;
+	}
+
+	sl_ps_profile.monitor_interval = sidev->ps_params.timeout_ms;
+
+	beacon_interval = siwx91x_get_connected_ap_beacon_interval_ms();
+	/* 1000ms is arbitrary sane value */
+	sl_ps_profile.listen_interval = MIN(beacon_interval * sidev->ps_params.listen_interval,
+					    1000);
+
+	if (sidev->ps_params.wakeup_mode == WIFI_PS_WAKEUP_MODE_LISTEN_INTERVAL &&
+	    !sidev->ps_params.listen_interval) {
+		LOG_INF("Disabling listen interval based wakeup until connection establishes");
+	}
+	if (sidev->ps_params.wakeup_mode == WIFI_PS_WAKEUP_MODE_DTIM ||
+	    !sidev->ps_params.listen_interval) {
+		sl_ps_profile.dtim_aligned_type = 1;
+	} else if (sidev->ps_params.wakeup_mode == WIFI_PS_WAKEUP_MODE_LISTEN_INTERVAL) {
+		sl_ps_profile.dtim_aligned_type = 0;
+	} else {
+		/* Already sanitized by siwx91x_set_power_save() */
+		return -EINVAL;
+	}
+
+out:
+	status = sl_wifi_set_performance_profile(&sl_ps_profile);
+	return status ? -EIO : 0;
+}
+
+static int siwx91x_set_power_save(const struct device *dev, struct wifi_ps_params *params)
+{
+	struct siwx91x_dev *sidev = dev->data;
+	int status;
+
+	__ASSERT(params, "params cannot be NULL");
+
+	switch (params->type) {
+	case WIFI_PS_PARAM_STATE:
+		sidev->ps_params.enabled = params->enabled;
+		break;
+	case WIFI_PS_PARAM_MODE:
+		if (params->mode != WIFI_PS_MODE_LEGACY) {
+			params->fail_reason = WIFI_PS_PARAM_FAIL_OPERATION_NOT_SUPPORTED;
+			return -ENOTSUP;
+		}
+		break;
+	case WIFI_PS_PARAM_LISTEN_INTERVAL:
+		sidev->ps_params.listen_interval = params->listen_interval;
+		break;
+	case WIFI_PS_PARAM_WAKEUP_MODE:
+		if (params->wakeup_mode != WIFI_PS_WAKEUP_MODE_LISTEN_INTERVAL &&
+		    params->wakeup_mode != WIFI_PS_WAKEUP_MODE_DTIM) {
+			params->fail_reason = WIFI_PS_PARAM_FAIL_OPERATION_NOT_SUPPORTED;
+			return -ENOTSUP;
+		}
+		sidev->ps_params.wakeup_mode = params->wakeup_mode;
+		break;
+	case WIFI_PS_PARAM_TIMEOUT:
+		/* 1000ms is arbitrary sane value */
+		if (params->timeout_ms < SLI_DEFAULT_MONITOR_INTERVAL ||
+		    params->timeout_ms > 1000) {
+			params->fail_reason = WIFI_PS_PARAM_FAIL_CMD_EXEC_FAIL;
+			return -EINVAL;
+		}
+		sidev->ps_params.timeout_ms = params->timeout_ms;
+		break;
+	case WIFI_PS_PARAM_EXIT_STRATEGY:
+		if (params->exit_strategy != WIFI_PS_EXIT_EVERY_TIM &&
+		    params->exit_strategy != WIFI_PS_EXIT_CUSTOM_ALGO) {
+			params->fail_reason = WIFI_PS_PARAM_FAIL_OPERATION_NOT_SUPPORTED;
+			return -ENOTSUP;
+		}
+		sidev->ps_params.exit_strategy = params->exit_strategy;
+		break;
+	default:
+		params->fail_reason = WIFI_PS_PARAM_FAIL_CMD_EXEC_FAIL;
+		return -EINVAL;
+	}
+	status = siwx91x_apply_power_save(sidev);
+	if (status) {
+		params->fail_reason = WIFI_PS_PARAM_FAIL_CMD_EXEC_FAIL;
+		return status;
+	}
+	return 0;
+}
+
 static unsigned int siwx91x_on_join(sl_wifi_event_t event,
 				    char *result, uint32_t result_size, void *arg)
 {
@@ -275,6 +408,8 @@ static unsigned int siwx91x_on_join(sl_wifi_event_t event,
 	siwx91x_on_join_ipv4(sidev);
 	siwx91x_on_join_ipv6(sidev);
 
+	siwx91x_apply_power_save(sidev);
+
 	return 0;
 }
 
@@ -1439,6 +1574,7 @@ static const struct wifi_mgmt_ops siwx91x_mgmt = {
 	.get_stats		= siwx91x_stats,
 #endif
 	.get_version		= siwx91x_get_version,
+	.set_power_save		= siwx91x_set_power_save,
 };
 
 static const struct net_wifi_mgmt_offload siwx91x_api = {
@@ -1452,6 +1588,9 @@ static const struct net_wifi_mgmt_offload siwx91x_api = {
 };
 
 static struct siwx91x_dev sidev = {
+	.ps_params.enabled = WIFI_PS_DISABLED,
+	.ps_params.exit_strategy = WIFI_PS_EXIT_EVERY_TIM,
+	.ps_params.wakeup_mode = WIFI_PS_WAKEUP_MODE_DTIM,
 	.max_num_sta = CONFIG_WIFI_MGMT_AP_MAX_NUM_STA,
 };
 

drivers/wifi/siwx91x/siwx91x_wifi.h

@@ -21,6 +21,7 @@ struct siwx91x_dev {
 	enum wifi_iface_state scan_prev_state;
 	scan_result_cb_t scan_res_cb;
 	uint16_t scan_max_bss_cnt;
+	struct wifi_ps_params ps_params;
 	uint8_t max_num_sta;
 	bool reboot_needed;
 	bool hidden_ssid;