This patch fixes the TSF offset calculation for staggered Beacon frames
and sets ATH_BCBUF back to the earlier value 4 to enable multi-BSS
configurations of up to four BSSes.
Signed-off-by: Jouni Malinen <[email protected]>
---
drivers/net/wireless/ath9k/ath9k.h | 3 +-
drivers/net/wireless/ath9k/beacon.c | 50 ++++++++++++++++++------------------
2 files changed, 27 insertions(+), 26 deletions(-)
--- wireless-testing.orig/drivers/net/wireless/ath9k/ath9k.h 2009-03-12 21:48:52.000000000 +0200
+++ wireless-testing/drivers/net/wireless/ath9k/ath9k.h 2009-03-12 21:49:47.000000000 +0200
@@ -390,6 +390,7 @@ void ath_tx_aggr_resume(struct ath_softc
struct ath_vif {
int av_bslot;
+ __le64 tsf_adjust; /* TSF adjustment for staggered beacons */
enum nl80211_iftype av_opmode;
struct ath_buf *av_bcbuf;
struct ath_tx_control av_btxctl;
@@ -406,7 +407,7 @@ struct ath_vif {
* number of beacon intervals, the game's up.
*/
#define BSTUCK_THRESH (9 * ATH_BCBUF)
-#define ATH_BCBUF 1
+#define ATH_BCBUF 4
#define ATH_DEFAULT_BINTVAL 100 /* TU */
#define ATH_DEFAULT_BMISS_LIMIT 10
#define IEEE80211_MS_TO_TU(x) (((x) * 1000) / 1024)
--- wireless-testing.orig/drivers/net/wireless/ath9k/beacon.c 2009-03-12 21:48:52.000000000 +0200
+++ wireless-testing/drivers/net/wireless/ath9k/beacon.c 2009-03-12 21:49:55.000000000 +0200
@@ -153,6 +153,8 @@ static struct ath_buf *ath_beacon_genera
bf->bf_mpdu = skb;
if (skb == NULL)
return NULL;
+ ((struct ieee80211_mgmt *)skb->data)->u.beacon.timestamp =
+ avp->tsf_adjust;
info = IEEE80211_SKB_CB(skb);
if (info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ) {
@@ -253,7 +255,6 @@ int ath_beacon_alloc(struct ath_wiphy *a
{
struct ath_softc *sc = aphy->sc;
struct ath_vif *avp;
- struct ieee80211_hdr *hdr;
struct ath_buf *bf;
struct sk_buff *skb;
__le64 tstamp;
@@ -316,42 +317,33 @@ int ath_beacon_alloc(struct ath_wiphy *a
tstamp = ((struct ieee80211_mgmt *)skb->data)->u.beacon.timestamp;
sc->beacon.bc_tstamp = le64_to_cpu(tstamp);
-
- /*
- * Calculate a TSF adjustment factor required for
- * staggered beacons. Note that we assume the format
- * of the beacon frame leaves the tstamp field immediately
- * following the header.
- */
+ /* Calculate a TSF adjustment factor required for staggered beacons. */
if (avp->av_bslot > 0) {
u64 tsfadjust;
- __le64 val;
int intval;
intval = sc->hw->conf.beacon_int ?
sc->hw->conf.beacon_int : ATH_DEFAULT_BINTVAL;
/*
- * The beacon interval is in TU's; the TSF in usecs.
- * We figure out how many TU's to add to align the
- * timestamp then convert to TSF units and handle
- * byte swapping before writing it in the frame.
- * The hardware will then add this each time a beacon
- * frame is sent. Note that we align vif's 1..N
- * and leave vif 0 untouched. This means vap 0
- * has a timestamp in one beacon interval while the
- * others get a timestamp aligned to the next interval.
+ * Calculate the TSF offset for this beacon slot, i.e., the
+ * number of usecs that need to be added to the timestamp field
+ * in Beacon and Probe Response frames. Beacon slot 0 is
+ * processed at the correct offset, so it does not require TSF
+ * adjustment. Other slots are adjusted to get the timestamp
+ * close to the TBTT for the BSS.
*/
- tsfadjust = (intval * (ATH_BCBUF - avp->av_bslot)) / ATH_BCBUF;
- val = cpu_to_le64(tsfadjust << 10); /* TU->TSF */
+ tsfadjust = intval * avp->av_bslot / ATH_BCBUF;
+ avp->tsf_adjust = cpu_to_le64(TU_TO_USEC(tsfadjust));
DPRINTF(sc, ATH_DBG_BEACON,
"stagger beacons, bslot %d intval %u tsfadjust %llu\n",
avp->av_bslot, intval, (unsigned long long)tsfadjust);
- hdr = (struct ieee80211_hdr *)skb->data;
- memcpy(&hdr[1], &val, sizeof(val));
- }
+ ((struct ieee80211_mgmt *)skb->data)->u.beacon.timestamp =
+ avp->tsf_adjust;
+ } else
+ avp->tsf_adjust = cpu_to_le64(0);
bf->bf_mpdu = skb;
bf->bf_buf_addr = bf->bf_dmacontext =
@@ -447,8 +439,16 @@ void ath_beacon_tasklet(unsigned long da
tsf = ath9k_hw_gettsf64(ah);
tsftu = TSF_TO_TU(tsf>>32, tsf);
slot = ((tsftu % intval) * ATH_BCBUF) / intval;
- vif = sc->beacon.bslot[(slot + 1) % ATH_BCBUF];
- aphy = sc->beacon.bslot_aphy[(slot + 1) % ATH_BCBUF];
+ /*
+ * Reverse the slot order to get slot 0 on the TBTT offset that does
+ * not require TSF adjustment and other slots adding
+ * slot/ATH_BCBUF * beacon_int to timestamp. For example, with
+ * ATH_BCBUF = 4, we process beacon slots as follows: 3 2 1 0 3 2 1 ..
+ * and slot 0 is at correct offset to TBTT.
+ */
+ slot = ATH_BCBUF - slot - 1;
+ vif = sc->beacon.bslot[slot];
+ aphy = sc->beacon.bslot_aphy[slot];
DPRINTF(sc, ATH_DBG_BEACON,
"slot %d [tsf %llu tsftu %u intval %u] vif %p\n",
--
Jouni Malinen PGP id EFC895FA