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Bluetooth: Controller: Add internal comments in BIS LLL code

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Add internal comments explaining the control flow in the
BIS synchronization in LLL.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>
This commit is contained in:
Vinayak Kariappa Chettimada 2022-11-17 08:52:29 +05:30 • committed by Carles Cufí
commit 0dfa37b7e1
1 changed files with 39 additions and 6 deletions
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45
subsys/bluetooth/controller/ll_sw/nordic/lll/lll_sync_iso.c
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@ -239,7 +239,9 @@ static int prepare_cb_common(struct lll_prepare_param *p)
util_bis_aa_le32(lll->bis_curr, lll->seed_access_addr, access_addr);
data_chan_id = lll_chan_id(access_addr);
/* Calculate the radio channel to use for ISO event */
/* Calculate the radio channel to use for ISO event and hence store the
* channel to be used for control subevent.
*/
data_chan_use = lll_chan_iso_event(event_counter, data_chan_id,
lll->data_chan_map,
lll->data_chan_count,
@ -263,7 +265,7 @@ static int prepare_cb_common(struct lll_prepare_param *p)
access_addr);
data_chan_id = lll_chan_id(access_addr);
/* Calculate the radio channel to use for ISO event */
/* Calculate the channel id for the next BIS subevent */
data_chan_use = lll_chan_iso_event(event_counter,
data_chan_id,
lll->data_chan_map,
@ -555,6 +557,7 @@ static void isr_rx(void *param)
handle = lll->stream_handle[lll->stream_curr];
stream = ull_sync_iso_lll_stream_get(handle);
/* store the received PDU */
if ((lll->bis_curr == stream->bis_index) && pdu->len &&
!lll->payload[bis_idx][payload_index] &&
((payload_index >= lll->payload_tail) ||
@ -572,65 +575,94 @@ isr_rx_done:
isr_rx_find_subevent:
/* FIXME: Sequential or Interleaved BIS subevents decision */
/* Sequential Rx complete flow pseudo code */
/* NOTE: below code is for Sequential Rx only */
/* Find the next (bn_curr)th subevent to receive PDU */
while (lll->bn_curr < lll->bn) {
lll->bn_curr++;
/* Find the index of the (bn_curr)th Rx PDU buffer */
payload_index = lll->payload_tail + (lll->bn_curr - 1U);
if (payload_index >= lll->payload_count_max) {
payload_index -= lll->payload_count_max;
}
/* Check if (bn_curr)th Rx PDU has been received */
if (!lll->payload[bis_idx][payload_index]) {
/* Receive the (bn_curr)th Rx PDU of bis_curr */
bis = lll->bis_curr;
/* Receive the (bn_curr)th Rx PDU of bis_curr */
goto isr_rx_next_subevent;
}
/* (bn_curr)th Rx PDU already received, skip subevent */
skipped++;
}
/* Find the next repetition (irc_curr)th subevent to receive PDU */
if (lll->irc_curr < lll->irc) {
if (!new_burst) {
lll->bn_curr = 1U;
lll->irc_curr++;
/* Find the index of the (irc_curr)th bn = 1 Rx PDU
* buffer.
*/
payload_index = lll->payload_tail;
/* Check if (irc_curr)th bn = 1 Rx PDU has been
* received.
*/
if (!lll->payload[bis_idx][payload_index]) {
/* Receive the (irc_curr)th bn = 1 Rx PDU of
* bis_curr.
*/
bis = lll->bis_curr;
goto isr_rx_next_subevent;
} else {
/* bn = 1 Rx PDU already received, skip
* subevent.
*/
skipped++;
/* flag to skip successive repetitions if all
* bn PDUs have been received. i.e. the bn
* loop above did not find a PDU to be received.
*/
new_burst = 1U;
/* Receive the missing (bn_curr)th Rx PDU of
/* Find the missing (bn_curr)th Rx PDU of
* bis_curr
*/
goto isr_rx_find_subevent;
}
} else {
/* Skip all successive repetition reception as all
* bn PDUs have been received.
*/
skipped += (lll->irc - lll->irc_curr) * lll->bn;
lll->irc_curr = lll->irc;
}
}
/* Next pre-transmission subevent */
if (lll->ptc_curr < lll->ptc) {
lll->ptc_curr++;
/* Receive the (ptc_curr)th Rx PDU */
/* Receive the (ptc_curr)th Rx PDU of bis_curr */
bis = lll->bis_curr;
goto isr_rx_next_subevent;
}
/* Next BIS */
if (lll->bis_curr < lll->num_bis) {
const uint8_t stream_curr = lll->stream_curr + 1U;
struct lll_sync_iso_stream *stream;
uint16_t handle;
/* Next selected stream */
if (stream_curr < lll->stream_count) {
lll->stream_curr = stream_curr;
handle = lll->stream_handle[lll->stream_curr];
@ -688,6 +720,7 @@ isr_rx_find_subevent:
}
}
/* Control subevent */
if (!lll->ctrl && (lll->cssn_next != lll->cssn_curr)) {
/* Receive the control PDU and close the BIG event
* there after.