Bluetooth: controller: ULL: ull_adv_sync_hdr_set_clear update PDU in place

Enabling or disabling transmission of Constant Tone Extension with
periodic advertising PDUs requires update of a PDU content.
CTE_INFO field of periodic advertising PDU must be filled with
appropriate data. That operation may be done for periodic
advertising PDU (or chain of PDUs) filled with other payload that
wasn't enqueued towards LLL. In that situation PDUs are updated
in place, to avoid increase of memory consumption.

The commit changes ull_adv_sync_pdu_set_clear function to
make possible update of the advertising PDU in place.

Signed-off-by: Piotr Pryga <[email protected]>

Author: ppryga-nordic

subsys/bluetooth/controller/ll_sw/ull_adv_sync.c

@@ -884,7 +884,7 @@ uint8_t ull_adv_sync_pdu_set_clear(struct lll_adv_sync *lll_sync,
 				   void *hdr_data)
 {
 	struct pdu_adv_com_ext_adv *ter_com_hdr, *ter_com_hdr_prev;
-	struct pdu_adv_ext_hdr *ter_hdr, ter_hdr_prev;
+	struct pdu_adv_ext_hdr ter_hdr = { 0 }, ter_hdr_prev = { 0 };
 	uint8_t *ter_dptr, *ter_dptr_prev;
 	uint8_t acad_len_prev;
 	uint8_t ter_len_prev;
@@ -899,13 +899,10 @@ uint8_t ull_adv_sync_pdu_set_clear(struct lll_adv_sync *lll_sync,
 
 	/* Get common pointers from reference to previous tertiary PDU data */
 	ter_com_hdr_prev = (void *)&ter_pdu_prev->adv_ext_ind;
-	ter_hdr = (void *)ter_com_hdr_prev->ext_hdr_adv_data;
-	if (ter_com_hdr_prev->ext_hdr_len) {
-		ter_hdr_prev = *ter_hdr;
-	} else {
-		*(uint8_t *)&ter_hdr_prev = 0U;
+	if (ter_com_hdr_prev->ext_hdr_len != 0) {
+		ter_hdr_prev = ter_com_hdr_prev->ext_hdr;
 	}
-	ter_dptr_prev = ter_hdr->data;
+	ter_dptr_prev = ter_com_hdr_prev->ext_hdr.data;
 
 	/* Set common fields in reference to new tertiary PDU data buffer */
 	ter_pdu->type = ter_pdu_prev->type;
@@ -915,26 +912,29 @@ uint8_t ull_adv_sync_pdu_set_clear(struct lll_adv_sync *lll_sync,
 	ter_pdu->tx_addr = ter_pdu_prev->tx_addr;
 	ter_pdu->rx_addr = ter_pdu_prev->rx_addr;
 
+	/* Get common pointers from current tertiary PDU data.
+	 * It is possbile that the current tertiary is the same as
+	 * previous one. It may happen if update periodic advertising
+	 * chain in place.
+	 */
 	ter_com_hdr = (void *)&ter_pdu->adv_ext_ind;
 	ter_com_hdr->adv_mode = ter_com_hdr_prev->adv_mode;
-	ter_hdr = (void *)ter_com_hdr->ext_hdr_adv_data;
-	ter_dptr = ter_hdr->data;
-	*(uint8_t *)ter_hdr = 0U;
+	ter_dptr = ter_com_hdr->ext_hdr.data;
 
 	/* No AdvA in AUX_SYNC_IND */
 	/* No TargetA in AUX_SYNC_IND */
 
 #if defined(CONFIG_BT_CTLR_DF_ADV_CTE_TX)
 	/* If requested add or update CTEInfo */
 	if (hdr_add_fields & ULL_ADV_PDU_HDR_FIELD_CTE_INFO) {
-		ter_hdr->cte_info = 1;
+		ter_hdr.cte_info = 1;
 		cte_info = *(uint8_t *)hdr_data;
 		hdr_data = (uint8_t *)hdr_data + 1;
 		ter_dptr += sizeof(struct pdu_cte_info);
 	/* If CTEInfo exists in prev and is not requested to be removed */
 	} else if (!(hdr_rem_fields & ULL_ADV_PDU_HDR_FIELD_CTE_INFO) &&
 		   ter_hdr_prev.cte_info) {
-		ter_hdr->cte_info = 1;
+		ter_hdr.cte_info = 1;
 		ter_dptr += sizeof(struct pdu_cte_info);
 	}
 
@@ -950,9 +950,9 @@ uint8_t ull_adv_sync_pdu_set_clear(struct lll_adv_sync *lll_sync,
 	if ((hdr_add_fields & ULL_ADV_PDU_HDR_FIELD_AUX_PTR) ||
 	    (!(hdr_rem_fields & ULL_ADV_PDU_HDR_FIELD_AUX_PTR) &&
 	     ter_hdr_prev.aux_ptr)) {
-		ter_hdr->aux_ptr = 1;
+		ter_hdr.aux_ptr = 1;
 	}
-	if (ter_hdr->aux_ptr) {
+	if (ter_hdr.aux_ptr) {
 		ter_dptr += sizeof(struct pdu_adv_aux_ptr);
 	}
 	if (ter_hdr_prev.aux_ptr) {
@@ -965,7 +965,7 @@ uint8_t ull_adv_sync_pdu_set_clear(struct lll_adv_sync *lll_sync,
 	if (ter_hdr_prev.tx_pwr) {
 		ter_dptr_prev++;
 
-		ter_hdr->tx_pwr = 1;
+		ter_hdr.tx_pwr = 1;
 		ter_dptr++;
 	}
 
@@ -974,10 +974,15 @@ uint8_t ull_adv_sync_pdu_set_clear(struct lll_adv_sync *lll_sync,
 	hdr_buf_len = ter_com_hdr_prev->ext_hdr_len +
 		      PDU_AC_EXT_HEADER_SIZE_MIN;
 	if (ter_len_prev <= hdr_buf_len) {
+		/* There are some data, except ACAD, in extended header if ter_len_prev
+		 * equals to hdr_buf_len. There is ACAD if the size of ter_len_prev
+		 * is smaller than hdr_buf_len.
+		 */
 		acad_len_prev = hdr_buf_len - ter_len_prev;
 		ter_len_prev += acad_len_prev;
 		ter_dptr_prev += acad_len_prev;
 	} else {
+		/* There are no data in extended header, all flags are zeros. */
 		acad_len_prev = 0;
 		/* NOTE: If no flags are set then extended header length will be
 		 *       zero. Under this condition the current ter_len_prev
@@ -1060,14 +1065,14 @@ uint8_t ull_adv_sync_pdu_set_clear(struct lll_adv_sync *lll_sync,
 	}
 
 	/* Tx Power */
-	if (ter_hdr->tx_pwr) {
+	if (ter_hdr.tx_pwr) {
 		*--ter_dptr = *--ter_dptr_prev;
 	}
 
 	/* No SyncInfo in AUX_SYNC_IND */
 
 	/* AuxPtr */
-	if (ter_hdr->aux_ptr) {
+	if (ter_hdr.aux_ptr) {
 		/* ToDo Update setup of aux_ptr - check documentation */
 		if (ter_hdr_prev.aux_ptr) {
 			ter_dptr_prev -= sizeof(struct pdu_adv_aux_ptr);
@@ -1082,7 +1087,7 @@ uint8_t ull_adv_sync_pdu_set_clear(struct lll_adv_sync *lll_sync,
 	/* No ADI in AUX_SYNC_IND*/
 
 #if defined(CONFIG_BT_CTLR_DF_ADV_CTE_TX)
-	if (ter_hdr->cte_info) {
+	if (ter_hdr.cte_info) {
 		if (hdr_add_fields & ULL_ADV_PDU_HDR_FIELD_CTE_INFO) {
 			*--ter_dptr = cte_info;
 		} else {
@@ -1094,6 +1099,10 @@ uint8_t ull_adv_sync_pdu_set_clear(struct lll_adv_sync *lll_sync,
 	/* No TargetA in AUX_SYNC_IND */
 	/* No AdvA in AUX_SYNC_IND */
 
+	if (ter_com_hdr->ext_hdr_len != 0) {
+		ter_com_hdr->ext_hdr = ter_hdr;
+	}
+
 	return 0;
 }