Bluetooth: controller: CIS Central fixes
- New calculation of Max_PDU for framed case according to BT Core 5.4
- Fix CIS_Offset calculation for multiple CIS usecase
- Fix resume ticker setup for central
Signed-off-by: Morten Priess <mtpr@oticon.com>
diff --git a/subsys/bluetooth/controller/ll_sw/ull_central_iso.c b/subsys/bluetooth/controller/ll_sw/ull_central_iso.c
index e601673..172bc28 100644
--- a/subsys/bluetooth/controller/ll_sw/ull_central_iso.c
+++ b/subsys/bluetooth/controller/ll_sw/ull_central_iso.c
@@ -44,6 +44,8 @@
#include "hal/debug.h"
+#define SDU_MAX_DRIFT_PPM 100
+
/* Setup cache for CIG commit transaction */
static struct {
struct ll_conn_iso_group group;
@@ -167,6 +169,44 @@
return BT_HCI_ERR_SUCCESS;
}
+static void set_bn_max_pdu(bool framed, uint32_t iso_interval, uint32_t sdu_interval,
+ uint16_t max_sdu, uint8_t *bn, uint8_t *max_pdu)
+{
+ uint32_t ceil_f_x_max_sdu;
+ uint16_t max_pdu_bn1;
+ uint32_t max_drift;
+ uint32_t ceil_f;
+
+ if (framed) {
+ /* Framed (From ES-18002):
+ * Max_PDU >= ((ceil(F) x 5 + ceil(F x Max_SDU)) / BN) + 2
+ * F = (1 + MaxDrift) x ISO_Interval / SDU_Interval
+ * SegmentationHeader + TimeOffset = 5 bytes
+ * Continuation header = 2 bytes
+ * MaxDrift (Max. allowed SDU delivery timing drift) = 100 ppm
+ */
+ max_drift = ceiling_fraction(SDU_MAX_DRIFT_PPM * sdu_interval, 1000000U);
+ ceil_f = ceiling_fraction(iso_interval + max_drift, sdu_interval);
+ ceil_f_x_max_sdu = ceiling_fraction(max_sdu * (iso_interval + max_drift),
+ sdu_interval);
+
+ /* Strategy: Keep lowest possible BN.
+ * TODO: Implement other strategies, possibly as policies.
+ */
+ max_pdu_bn1 = ceil_f * 5 + ceil_f_x_max_sdu;
+ *bn = ceiling_fraction(max_pdu_bn1, CONFIG_BT_CTLR_ISO_TX_BUFFER_SIZE);
+ *max_pdu = ceiling_fraction(max_pdu_bn1, *bn) + 2;
+ } else {
+ /* For unframed, ISO_Interval must be N x SDU_Interval */
+ LL_ASSERT(iso_interval % sdu_interval == 0);
+
+ /* Core 5.3 Vol 6, Part G section 2.1:
+ * BN >= ceil(Max_SDU/Max_PDU * ISO_Interval/SDU_Interval)
+ */
+ *bn = ceiling_fraction(max_sdu * iso_interval, (*max_pdu) * sdu_interval);
+ }
+}
+
/* TODO:
* - Drop retransmissions to stay within Max_Transmission_Latency instead of asserting
@@ -278,30 +318,29 @@
tx = cig->c_sdu_interval && cis->c_max_sdu;
rx = cig->p_sdu_interval && cis->p_max_sdu;
- if (cis->framed) {
- cis->lll.tx.max_octets =
- ceiling_fraction(cis->c_max_sdu * cig->c_sdu_interval,
- iso_interval_us);
- cis->lll.rx.max_octets =
- ceiling_fraction(cis->p_max_sdu * cig->c_sdu_interval,
- iso_interval_us);
- } else {
- /* For unframed, ISO_Interval must be N x SDU_Interval */
- LL_ASSERT(iso_interval_us % cig->c_sdu_interval == 0);
+ /* Use Max_PDU = MIN(<buffer_size>, Max_SDU) as default. May be changed by
+ * set_bn_max_pdu.
+ */
+ cis->lll.tx.max_octets = MIN(CONFIG_BT_CTLR_ISO_TX_BUFFER_SIZE,
+ cis->c_max_sdu);
+ cis->lll.rx.max_octets = MIN(251, cis->p_max_sdu);
- /* Use Max_PDU = MIN(<buffer_size>, Max_SDU) */
- cis->lll.tx.max_octets = MIN(CONFIG_BT_CTLR_ISO_TX_BUFFER_SIZE,
- cis->c_max_sdu);
- cis->lll.rx.max_octets = MIN(251, cis->p_max_sdu);
+ /* Calculate BN and Max_PDU (framed) for both directions */
+ if (tx) {
+ set_bn_max_pdu(cis->framed, iso_interval_us, cig->c_sdu_interval,
+ cis->c_max_sdu, &cis->lll.tx.burst_number,
+ &cis->lll.tx.max_octets);
+ } else {
+ cis->lll.tx.burst_number = 0;
}
- /* BN >= Max_SDU/Max_PDU * ISO_Interval/SDU_Interval */
- cis->lll.tx.burst_number = tx ?
- ceiling_fraction(cis->c_max_sdu * iso_interval_us,
- cis->lll.tx.max_octets * cig->c_sdu_interval) : 0;
- cis->lll.rx.burst_number = rx ?
- ceiling_fraction(cis->p_max_sdu * iso_interval_us,
- cis->lll.rx.max_octets * cig->p_sdu_interval) : 0;
+ if (rx) {
+ set_bn_max_pdu(cis->framed, iso_interval_us, cig->p_sdu_interval,
+ cis->p_max_sdu, &cis->lll.rx.burst_number,
+ &cis->lll.rx.max_octets);
+ } else {
+ cis->lll.rx.burst_number = 0;
+ }
}
/* Calculate SE_Length */
@@ -621,7 +660,6 @@
int16_t conn_events_since_ref;
uint32_t iso_interval_us;
uint32_t time_since_ref;
- uint32_t acl_offset;
c = ll_conn_iso_stream_get_by_group(cig, &handle_iter);
if (c->cis_id != cis->cis_id && c->lll.active) {
@@ -630,9 +668,8 @@
time_since_ref = c->offset + conn_events_since_ref * conn->lll.interval *
CONN_INT_UNIT_US;
- iso_interval_us = cig->iso_interval * CONN_INT_UNIT_US;
- acl_offset = iso_interval_us - (time_since_ref % iso_interval_us);
- cis_offset = acl_offset + (cig->sync_delay - cis->sync_delay);
+ iso_interval_us = cig->iso_interval * ISO_INT_UNIT_US;
+ cis_offset = time_since_ref % iso_interval_us;
break;
}
}
diff --git a/subsys/bluetooth/controller/ll_sw/ull_conn_iso.c b/subsys/bluetooth/controller/ll_sw/ull_conn_iso.c
index 5bdbd39..00b60e5 100644
--- a/subsys/bluetooth/controller/ll_sw/ull_conn_iso.c
+++ b/subsys/bluetooth/controller/ll_sw/ull_conn_iso.c
@@ -442,7 +442,6 @@
uint32_t resume_timeout)
{
struct lll_conn_iso_group *cig;
- uint32_t ready_delay_us;
uint32_t resume_delay_us;
int32_t resume_offset_us;
uint8_t ticker_id;
@@ -458,26 +457,28 @@
}
cig->resume_cis = cis_handle;
- if (0) {
-#if defined(CONFIG_BT_CTLR_PHY)
- } else {
- struct ll_conn_iso_stream *cis;
- struct ll_conn *acl;
-
- cis = ll_conn_iso_stream_get(cis_handle);
- acl = ll_conn_get(cis->lll.acl_handle);
-
- ready_delay_us = lll_radio_rx_ready_delay_get(acl->lll.phy_rx, 1);
-#else
- } else {
- ready_delay_us = lll_radio_rx_ready_delay_get(0, 0);
-#endif /* CONFIG_BT_CTLR_PHY */
- }
-
resume_delay_us = EVENT_OVERHEAD_START_US;
resume_delay_us += EVENT_TICKER_RES_MARGIN_US;
- resume_delay_us += EVENT_JITTER_US;
- resume_delay_us += ready_delay_us;
+
+ if (cig->role == BT_HCI_ROLE_PERIPHERAL) {
+ /* Add peripheral specific delay */
+ resume_delay_us += EVENT_JITTER_US;
+ if (0) {
+#if defined(CONFIG_BT_CTLR_PHY)
+ } else {
+ struct ll_conn_iso_stream *cis;
+ struct ll_conn *acl;
+
+ cis = ll_conn_iso_stream_get(cis_handle);
+ acl = ll_conn_get(cis->lll.acl_handle);
+
+ resume_delay_us += lll_radio_rx_ready_delay_get(acl->lll.phy_rx, 1);
+#else
+ } else {
+ resume_delay_us += lll_radio_rx_ready_delay_get(0, 0);
+#endif /* CONFIG_BT_CTLR_PHY */
+ }
+ }
resume_offset_us = (int32_t)(resume_timeout - resume_delay_us);
LL_ASSERT(resume_offset_us >= 0);
@@ -631,8 +632,7 @@
#elif !defined(CONFIG_BT_CTLR_CENTRAL_ISO)
mfy.fp = lll_peripheral_iso_prepare;
#else
- mfy.fp = (cig->lll.role == BT_HCI_ROLE_PERIPHERAL) ? lll_peripheral_iso_prepare :
- lll_central_iso_prepare;
+ mfy.fp = IS_PERIPHERAL(cig) ? lll_peripheral_iso_prepare : lll_central_iso_prepare;
#endif
if (IS_PERIPHERAL(cig) && cig->sca_update) {
