Bluetooth: Controller: nRF51x: Fix regression in encrypted connection

Fix regression in encrypted connection introduced in
commit f3deccd ("Bluetooth: Controller: CCM read data
to early when DF enabled on PHY 1M").

Due to this nRF51x SoC hang waiting to encrypt and/or
check MIC.

Signed-off-by: Vinayak Kariappa Chettimada <[email protected]>

Author: cvinayak

subsys/bluetooth/controller/ll_sw/nordic/hal/nrf5/radio/radio.c

@@ -1861,10 +1861,8 @@ static void *radio_ccm_ext_rx_pkt_set(struct ccm *cnf, uint8_t phy, uint8_t pdu_
 #endif /* CONFIG_HAS_HW_NRF_RADIO_BLE_CODED */
 #endif /* CONFIG_BT_CTLR_PHY_CODED */
 	}
-#endif /* !CONFIG_SOC_SERIES_NRF51X */
 
-#if !defined(CONFIG_SOC_SERIES_NRF51X) && \
-	!defined(CONFIG_SOC_NRF52832) && \
+#if !defined(CONFIG_SOC_NRF52832) && \
 	(!defined(CONFIG_BT_CTLR_DATA_LENGTH_MAX) || \
 	 (CONFIG_BT_CTLR_DATA_LENGTH_MAX < ((HAL_RADIO_PDU_LEN_MAX) - 4U)))
 	uint8_t max_len = (NRF_RADIO->PCNF1 & RADIO_PCNF1_MAXLEN_Msk) >>
@@ -1889,6 +1887,11 @@ static void *radio_ccm_ext_rx_pkt_set(struct ccm *cnf, uint8_t phy, uint8_t pdu_
 	}
 #endif /* CONFIG_HAS_HW_NRF_CCM_HEADERMASK */
 
+#else /* CONFIG_SOC_SERIES_NRF51X */
+	hal_trigger_crypt_ppi_config();
+	hal_radio_nrf_ppi_channels_enable(BIT(HAL_TRIGGER_CRYPT_PPI));
+#endif /* CONFIG_SOC_SERIES_NRF51X */
+
 	NRF_CCM->MODE = mode;
 	NRF_CCM->CNFPTR = (uint32_t)cnf;
 	NRF_CCM->INPTR = (uint32_t)_pkt_scratch;