Bluetooth: Controller: Fix missing window widening in ull_periph_setup

No window widening was applied to conn_offset_us causing the initial
ticker_cb to get called slightly too late

Apply window_widening_periodic_us to conn_offset_us, since this is the
worst-case window widening (win_offset is not allowed to be larger than
a connection interval) and is applied in the LLL window size already

Fixes EBQ failure in LL/TIM/PER/BV-02-C

Signed-off-by: Troels Nilsson <[email protected]>

Author: Tronil

subsys/bluetooth/controller/ll_sw/ull_peripheral.c

@@ -418,6 +418,19 @@ void ull_periph_setup(struct node_rx_pdu *rx, struct node_rx_ftr *ftr,
 	conn_offset_us -= EVENT_TICKER_RES_MARGIN_US;
 	conn_offset_us -= EVENT_JITTER_US;
 	conn_offset_us -= ready_delay_us;
+	/*
+	 * NOTE: Correct window widening for the first connection will be:
+	 *
+	 * conn_offset_us -=
+	 *         DIV_ROUND_UP(((lll_clock_ppm_local_get() +
+	 *                        lll_clock_ppm_get(conn->periph.sca)) *
+	 *                       (win_offset * CONN_INT_UNIT_US + win_delay_us)), USEC_PER_SEC);
+	 *
+	 * But, as currently in the implementation the drift compensation uses the
+	 * `lll->periph.window_widening_periodic_us` value, we may as well use that value here
+	 * as well. Adding another value for LLL to use seems overkill for this one case.
+	 */
+	conn_offset_us -= lll->periph.window_widening_periodic_us;
 
 #if (CONFIG_BT_CTLR_ULL_HIGH_PRIO == CONFIG_BT_CTLR_ULL_LOW_PRIO)
 	/* disable ticker job, in order to chain stop and start to avoid RTC