mac80211_hwsim: fix beacon timing

A beacon period starts at TSF time 0. Spoof this by
rounding the starting beacon time to a multiple of the
beacon interval, and keep TBTT aligned on TSF adjustment.

Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index c54c5d17a03794d0792b0a663cbea93919ccf80d..b6e2caa024a7b5c17e0aa83071855c18533e3342 100644 (file)
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -362,6 +362,7 @@ struct mac80211_hwsim_data {
 
        /* difference between this hw's clock and the real clock, in usecs */
        s64 tsf_offset;
+       s64 bcn_delta;
 };
 
 
@@ -428,9 +429,12 @@ static void mac80211_hwsim_set_tsf(struct ieee80211_hw *hw,
 {
        struct mac80211_hwsim_data *data = hw->priv;
        u64 now = mac80211_hwsim_get_tsf(hw, vif);
+       u32 bcn_int = data->beacon_int;
        s64 delta = tsf - now;
 
        data->tsf_offset += delta;
+       /* adjust after beaconing with new timestamp at old TBTT */
+       data->bcn_delta = do_div(delta, bcn_int);
 }
 
 static void mac80211_hwsim_monitor_rx(struct ieee80211_hw *hw,
@@ -1018,6 +1022,12 @@ mac80211_hwsim_beacon(struct hrtimer *timer)
                hw, IEEE80211_IFACE_ITER_NORMAL,
                mac80211_hwsim_beacon_tx, hw);
 
+       /* beacon at new TBTT + beacon interval */
+       if (data->bcn_delta) {
+               bcn_int -= data->bcn_delta;
+               data->bcn_delta = 0;
+       }
+
        next_bcn = ktime_add(hrtimer_get_expires(timer),
                             ns_to_ktime(bcn_int * 1000));
        tasklet_hrtimer_start(&data->beacon_timer, next_bcn, HRTIMER_MODE_ABS);
@@ -1062,8 +1072,12 @@ static int mac80211_hwsim_config(struct ieee80211_hw *hw, u32 changed)
        if (!data->started || !data->beacon_int)
                tasklet_hrtimer_cancel(&data->beacon_timer);
        else if (!hrtimer_is_queued(&data->beacon_timer.timer)) {
+               u64 tsf = mac80211_hwsim_get_tsf(hw, NULL);
+               u32 bcn_int = data->beacon_int;
+               u64 until_tbtt = bcn_int - do_div(tsf, bcn_int);
+
                tasklet_hrtimer_start(&data->beacon_timer,
-                                     ns_to_ktime(data->beacon_int * 1000),
+                                     ns_to_ktime(until_tbtt * 1000),
                                      HRTIMER_MODE_REL);
        }
 
@@ -1123,11 +1137,15 @@ static void mac80211_hwsim_bss_info_changed(struct ieee80211_hw *hw,
                if (data->started &&
                    !hrtimer_is_queued(&data->beacon_timer.timer) &&
                    info->enable_beacon) {
+                       u64 tsf, until_tbtt;
+                       u32 bcn_int;
                        if (WARN_ON(!data->beacon_int))
                                data->beacon_int = 1000 * 1024;
+                       tsf = mac80211_hwsim_get_tsf(hw, vif);
+                       bcn_int = data->beacon_int;
+                       until_tbtt = bcn_int - do_div(tsf, bcn_int);
                        tasklet_hrtimer_start(&data->beacon_timer,
-                                             ns_to_ktime(data->beacon_int *
-                                                         1000),
+                                             ns_to_ktime(until_tbtt * 1000),
                                              HRTIMER_MODE_REL);
                } else if (!info->enable_beacon)
                        tasklet_hrtimer_cancel(&data->beacon_timer);