staging: vt6656: refactor power save operation

At present the power save wake uses the listening interval and
the slow path to wake up.

The following using a beacon interval of 100 and
listen interval of 5.

The TBTT set at 100 wake-up sequence;
100 TBTT wake-up set to listen interval.
200 TBTT
300 TBTT
400 TBTT --> call vnt_next_tbtt_wakeup on slow path
	Beacon heard and passed through at the approx 500 interval.
500 TBTT
600 TBTT wake-up set to listen interval

The TBTT set at 500 wake-up sequence and always listen flagged on;
100 No TBTT
200 No TBTT
300 No TBTT
400 No TBTT
500 TBTT - beacon heard and passed through
600 No TBTT

A further enhancement because the TBTT is more precise
the dtim_period can be used instead.

When Power save is off the TBTT continues to run at the listen
interval but all the other beacons are passed.

The code in vnt_int_process_data is no longer required.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/5a188bd8-7049-8063-f24d-96768ce9a6ed@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 11 insertions, 27 deletions

diff --git a/drivers/staging/vt6656/device.h b/drivers/staging/vt6656/device.h
index 4d596853a3ee..d19d802b5d4f 100644
--- a/drivers/staging/vt6656/device.h
+++ b/drivers/staging/vt6656/device.h
@@ -383,8 +383,6 @@ struct vnt_private {
 	u8 bb_pre_ed_rssi;
 	u8 bb_pre_ed_index;
 
-	u16 wake_up_count;
-
 	/* command timer */
 	struct delayed_work run_command_work;
 
diff --git a/drivers/staging/vt6656/main_usb.c b/drivers/staging/vt6656/main_usb.c
index 7db1e044ad26..b5790d4d7152 100644
--- a/drivers/staging/vt6656/main_usb.c
+++ b/drivers/staging/vt6656/main_usb.c
@@ -824,10 +824,17 @@ static void vnt_bss_info_changed(struct ieee80211_hw *hw,
 	if (changed & (BSS_CHANGED_ASSOC | BSS_CHANGED_BEACON_INFO) &&
 	    priv->op_mode != NL80211_IFTYPE_AP) {
 		if (conf->assoc && conf->beacon_rate) {
+			u16 ps_beacon_int = conf->beacon_int;
+
+			if (conf->dtim_period)
+				ps_beacon_int *= conf->dtim_period;
+			else if (hw->conf.listen_interval)
+				ps_beacon_int *= hw->conf.listen_interval;
+
 			vnt_mac_reg_bits_on(priv, MAC_REG_TFTCTL,
 					    TFTCTL_TSFCNTREN);
 
-			vnt_mac_set_beacon_interval(priv, conf->beacon_int);
+			vnt_mac_set_beacon_interval(priv, ps_beacon_int);
 
 			vnt_reset_next_tbtt(priv, conf->beacon_int);
 
@@ -835,7 +842,7 @@ static void vnt_bss_info_changed(struct ieee80211_hw *hw,
 				       conf->sync_tsf, priv->current_tsf);
 
 			vnt_update_next_tbtt(priv,
-					     conf->sync_tsf, conf->beacon_int);
+					     conf->sync_tsf, ps_beacon_int);
 		} else {
 			vnt_clear_current_tsf(priv);
 
diff --git a/drivers/staging/vt6656/power.c b/drivers/staging/vt6656/power.c
index d160a0773943..2f49c870272a 100644
--- a/drivers/staging/vt6656/power.c
+++ b/drivers/staging/vt6656/power.c
@@ -63,16 +63,8 @@ void vnt_enable_power_saving(struct vnt_private *priv, u16 listen_interval)
 	 */
 	vnt_mac_reg_bits_on(priv, MAC_REG_PSCTL, PSCTL_GO2DOZE);
 
-	if (listen_interval >= 2) {
-		/* clear always listen beacon */
-		vnt_mac_reg_bits_off(priv, MAC_REG_PSCTL, PSCTL_ALBCN);
-
-		/* first time set listen next beacon */
-		vnt_mac_reg_bits_on(priv, MAC_REG_PSCTL, PSCTL_LNBCN);
-	} else {
-		/* always listen beacon */
-		vnt_mac_reg_bits_on(priv, MAC_REG_PSCTL, PSCTL_ALBCN);
-	}
+	/* always listen beacon */
+	vnt_mac_reg_bits_on(priv, MAC_REG_PSCTL, PSCTL_ALBCN);
 
 	dev_dbg(&priv->usb->dev,  "PS:Power Saving Mode Enable...\n");
 }
diff --git a/drivers/staging/vt6656/usbpipe.c b/drivers/staging/vt6656/usbpipe.c
index e8efdeadb1a7..5603f3cbb33c 100644
--- a/drivers/staging/vt6656/usbpipe.c
+++ b/drivers/staging/vt6656/usbpipe.c
@@ -202,19 +202,6 @@ static void vnt_int_process_data(struct vnt_private *priv)
 	if (int_data->isr0 & ISR_BNTX && priv->op_mode == NL80211_IFTYPE_AP)
 		vnt_schedule_command(priv, WLAN_CMD_BECON_SEND);
 
-	if (int_data->isr0 & ISR_TBTT &&
-	    priv->hw->conf.flags & IEEE80211_CONF_PS) {
-		if (!priv->wake_up_count)
-			priv->wake_up_count = priv->hw->conf.listen_interval;
-
-		if (priv->wake_up_count)
-			--priv->wake_up_count;
-
-		/* Turn on wake up to listen next beacon */
-		if (priv->wake_up_count == 1)
-			vnt_schedule_command(priv, WLAN_CMD_TBTT_WAKEUP);
-	}
-
 	priv->current_tsf = le64_to_cpu(int_data->tsf);
 
 	low_stats->dot11RTSSuccessCount += int_data->rts_success;