ath9k: Fix PS mode operation to receive buffered broadcast/multicast frames
The previous implementation was moving back to NETWORK SLEEP state
immediately after receiving a Beacon frame. This means that we are
unlikely to receive all the buffered broadcast/multicast frames that
would be sent after DTIM Beacon frames. Fix this by parsing the Beacon
frame and remaining awake, if needed, to receive the buffered
broadcast/multicast frames. The last buffered frame will trigger the
move back into NETWORK SLEEP state.
If the last broadcast/multicast frame is not received properly (or if
the AP fails to send it), the next Beacon frame will work as a backup
trigger for returning into NETWORK SLEEP.
A new debug type, PS (debug=0x800 module parameter), is added to make
it easier to debug potential power save issues in the
future. Currently, this is only used for the Beacon frame and buffered
broadcast/multicast receiving.
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 10ffc94..3425662 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -515,6 +515,7 @@
#define SC_OP_LED_ON BIT(13)
#define SC_OP_SCANNING BIT(14)
#define SC_OP_TSF_RESET BIT(15)
+#define SC_OP_WAIT_FOR_CAB BIT(16)
struct ath_bus_ops {
void (*read_cachesize)(struct ath_softc *sc, int *csz);
diff --git a/drivers/net/wireless/ath/ath9k/debug.h b/drivers/net/wireless/ath/ath9k/debug.h
index 23298b9..db845cf 100644
--- a/drivers/net/wireless/ath/ath9k/debug.h
+++ b/drivers/net/wireless/ath/ath9k/debug.h
@@ -29,6 +29,7 @@
ATH_DBG_BEACON = 0x00000100,
ATH_DBG_CONFIG = 0x00000200,
ATH_DBG_FATAL = 0x00000400,
+ ATH_DBG_PS = 0x00000800,
ATH_DBG_ANY = 0xffffffff
};
diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index 58bb26c..72e9283 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -473,6 +473,112 @@
spin_unlock_bh(&sc->rx.rxflushlock);
}
+static bool ath_beacon_dtim_pending_cab(struct sk_buff *skb)
+{
+ /* Check whether the Beacon frame has DTIM indicating buffered bc/mc */
+ struct ieee80211_mgmt *mgmt;
+ u8 *pos, *end, id, elen;
+ struct ieee80211_tim_ie *tim;
+
+ mgmt = (struct ieee80211_mgmt *)skb->data;
+ pos = mgmt->u.beacon.variable;
+ end = skb->data + skb->len;
+
+ while (pos + 2 < end) {
+ id = *pos++;
+ elen = *pos++;
+ if (pos + elen > end)
+ break;
+
+ if (id == WLAN_EID_TIM) {
+ if (elen < sizeof(*tim))
+ break;
+ tim = (struct ieee80211_tim_ie *) pos;
+ if (tim->dtim_count != 0)
+ break;
+ return tim->bitmap_ctrl & 0x01;
+ }
+
+ pos += elen;
+ }
+
+ return false;
+}
+
+static void ath_rx_ps_back_to_sleep(struct ath_softc *sc)
+{
+ sc->sc_flags &= ~(SC_OP_WAIT_FOR_BEACON | SC_OP_WAIT_FOR_CAB);
+ if (sc->hw->conf.flags & IEEE80211_CONF_PS)
+ ath9k_hw_setpower(sc->sc_ah, ATH9K_PM_NETWORK_SLEEP);
+}
+
+static void ath_rx_ps_beacon(struct ath_softc *sc, struct sk_buff *skb)
+{
+ struct ieee80211_mgmt *mgmt;
+
+ if (skb->len < 24 + 8 + 2 + 2)
+ return;
+
+ mgmt = (struct ieee80211_mgmt *)skb->data;
+ if (memcmp(sc->curbssid, mgmt->bssid, ETH_ALEN) != 0)
+ return; /* not from our current AP */
+
+ if (!(sc->hw->conf.flags & IEEE80211_CONF_PS)) {
+ /* We are not in PS mode anymore; remain awake */
+ DPRINTF(sc, ATH_DBG_PS, "Not in PS mode anymore, remain "
+ "awake\n");
+ sc->sc_flags &= ~(SC_OP_WAIT_FOR_BEACON | SC_OP_WAIT_FOR_CAB);
+ return;
+ }
+
+ if (ath_beacon_dtim_pending_cab(skb)) {
+ /*
+ * Remain awake waiting for buffered broadcast/multicast
+ * frames.
+ */
+ DPRINTF(sc, ATH_DBG_PS, "Received DTIM beacon indicating "
+ "buffered broadcast/multicast frame(s)\n");
+ sc->sc_flags |= SC_OP_WAIT_FOR_CAB;
+ return;
+ }
+
+ if (sc->sc_flags & SC_OP_WAIT_FOR_CAB) {
+ /*
+ * This can happen if a broadcast frame is dropped or the AP
+ * fails to send a frame indicating that all CAB frames have
+ * been delivered.
+ */
+ DPRINTF(sc, ATH_DBG_PS, "PS wait for CAB frames timed out\n");
+ }
+
+ /* No more broadcast/multicast frames to be received at this point. */
+ ath_rx_ps_back_to_sleep(sc);
+}
+
+static void ath_rx_ps(struct ath_softc *sc, struct sk_buff *skb)
+{
+ struct ieee80211_hdr *hdr;
+
+ hdr = (struct ieee80211_hdr *)skb->data;
+
+ /* Process Beacon and CAB receive in PS state */
+ if (ieee80211_is_beacon(hdr->frame_control))
+ ath_rx_ps_beacon(sc, skb);
+ else if ((sc->sc_flags & SC_OP_WAIT_FOR_CAB) &&
+ (ieee80211_is_data(hdr->frame_control) ||
+ ieee80211_is_action(hdr->frame_control)) &&
+ is_multicast_ether_addr(hdr->addr1) &&
+ !ieee80211_has_moredata(hdr->frame_control)) {
+ DPRINTF(sc, ATH_DBG_PS, "All PS CAB frames received, back to "
+ "sleep\n");
+ /*
+ * No more broadcast/multicast frames to be received at this
+ * point.
+ */
+ ath_rx_ps_back_to_sleep(sc);
+ }
+}
+
static void ath_rx_send_to_mac80211(struct ath_softc *sc, struct sk_buff *skb,
struct ieee80211_rx_status *rx_status)
{
@@ -667,8 +773,6 @@
rx_status.flag &= ~RX_FLAG_DECRYPTED;
}
- ath_rx_send_to_mac80211(sc, skb, &rx_status);
-
/* We will now give hardware our shiny new allocated skb */
bf->bf_mpdu = requeue_skb;
bf->bf_buf_addr = dma_map_single(sc->dev, requeue_skb->data,
@@ -680,6 +784,7 @@
bf->bf_mpdu = NULL;
DPRINTF(sc, ATH_DBG_FATAL,
"dma_mapping_error() on RX\n");
+ ath_rx_send_to_mac80211(sc, skb, &rx_status);
break;
}
bf->bf_dmacontext = bf->bf_buf_addr;
@@ -695,11 +800,11 @@
sc->rx.rxotherant = 0;
}
- if (ieee80211_is_beacon(fc) &&
- (sc->sc_flags & SC_OP_WAIT_FOR_BEACON)) {
- sc->sc_flags &= ~SC_OP_WAIT_FOR_BEACON;
- ath9k_hw_setpower(sc->sc_ah, ATH9K_PM_NETWORK_SLEEP);
- }
+ if (unlikely(sc->sc_flags & SC_OP_WAIT_FOR_BEACON))
+ ath_rx_ps(sc, skb);
+
+ ath_rx_send_to_mac80211(sc, skb, &rx_status);
+
requeue:
list_move_tail(&bf->list, &sc->rx.rxbuf);
ath_rx_buf_link(sc, bf);
