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Bluetooth: Controller: Replace Central connection spacing Kconfig

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Replace the BT_CTLR_ADVANCED_SCHEDULING_CENTRAL_CONN_SPACING
Kconfig with BT_CTLR_CENTRAL_SPACING to configure the
the spacing from the beginning of a central connection event
to beginning of the next central connection when supporting
multiple simulataneous central connections.

If the BT_CTLR_CENTRAL_SPACING in microseconds is smaller
then the required time reservation for a connection event,
for given maximum data length and PHY in use, then the
calculated time reservation will be used as the spacing
between consecution central connection events.

The change fixes an issue wherein use of old Kconfig with
higher values causes new central connections to be placed
in between already connected central role if there was
free time space available to fit the new connections time
reservation.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>
This commit is contained in:
Vinayak Kariappa Chettimada 2022-11-07 18:20:53 +05:30 • committed by Carles Cufí
commit a6beef4b26
4 changed files with 25 additions and 27 deletions
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31
subsys/bluetooth/controller/Kconfig.ll_sw_split
View file

@ -440,25 +440,24 @@ config BT_CTLR_SCHED_ADVANCED
Disabling this feature will lead to overlapping role in timespace Disabling this feature will lead to overlapping role in timespace
leading to skipped events amongst active roles. leading to skipped events amongst active roles.
config BT_CTLR_SCHED_ADVANCED_CENTRAL_CONN_SPACING config BT_CTLR_CENTRAL_SPACING
int "Advanced scheduling central preferred connection spacing" int "Central Connection Spacing"
depends on BT_CTLR_SCHED_ADVANCED depends on BT_CTLR_SCHED_ADVANCED
default 0 default 0
range 0 65535
help help
The central preferred connection spacing defines an additional spacing The preferred connection spacing between multiple simultaneous central
in microseconds, added to the fixed ~1250 us spacing obtained by enabling roles in microseconds. The Controller will calculate the required time
BT_CTLR_SCHED_ADVANCED. Specifying 0 (default) will obtain a spacing of reservation using the data length and PHY currently in use. The
~1250 us, whereas specifying 1250 will yield a spacing of ~2500 us. greater of the preferred spacing and the calculated time reservation
The spacing is defined as the distance in time between the anchor points will be used.
of the established central role connections. The precision is determined by the resolution of the platform
The precision is determined by the resolution of the platform dependent dependent ticker clock.
ticker clock. The upper range is a ceil value permitting any tuning of Controller's
When specifying values above 6.25 ms, the spacing may be unobtainable if radio handling overheads and to allow Coded PHY S8 coding scheme PDU
the connection interval becomes smaller than the total spacing. In that time, i.e. radio event overheads + 17040 (PDU Tx) + 150 (tIFS) + 4
case, modulo is applied and a total spacing of 15 ms on a 10 ms connection (active clock jitter) + 17040 (PDU rx) = (radio event overheads +
interval yields 5 ms spacing. 34234) microseconds.
For multiple connections, it may become impossible to honor the preferred
spacing, in which case overlapping will occur.
config BT_CTLR_LLL_PRIO config BT_CTLR_LLL_PRIO
int "Lower Link Layer (Radio) IRQ priority" if (BT_CTLR_ULL_LLL_PRIO_SUPPORT && !BT_CTLR_ZLI) int "Lower Link Layer (Radio) IRQ priority" if (BT_CTLR_ULL_LLL_PRIO_SUPPORT && !BT_CTLR_ZLI)

10
subsys/bluetooth/controller/ll_sw/nordic/lll/lll_scan.c
View file

@ -51,12 +51,6 @@
/* Maximum primary Advertising Radio Channels to scan */ /* Maximum primary Advertising Radio Channels to scan */
#define ADV_CHAN_MAX 3U #define ADV_CHAN_MAX 3U
#if defined(CONFIG_BT_CENTRAL) && defined(CONFIG_BT_CTLR_SCHED_ADVANCED)
#define CONN_SPACING CONFIG_BT_CTLR_SCHED_ADVANCED_CENTRAL_CONN_SPACING
#else
#define CONN_SPACING 0U
#endif /* CONFIG_BT_CENTRAL && CONFIG_BT_CTLR_SCHED_ADVANCED */
static int init_reset(void); static int init_reset(void);
static int prepare_cb(struct lll_prepare_param *p); static int prepare_cb(struct lll_prepare_param *p);
static int resume_prepare_cb(struct lll_prepare_param *p); static int resume_prepare_cb(struct lll_prepare_param *p);
@ -294,13 +288,13 @@ void lll_scan_prepare_connect_req(struct lll_scan *lll, struct pdu_adv *pdu_tx,
*conn_space_us = conn_offset_us; *conn_space_us = conn_offset_us;
pdu_tx->connect_ind.win_offset = sys_cpu_to_le16(0); pdu_tx->connect_ind.win_offset = sys_cpu_to_le16(0);
} else { } else {
uint32_t win_offset_us = lll->conn_win_offset_us + uint32_t win_offset_us = lll->conn_win_offset_us;
CONN_SPACING;
while ((win_offset_us & ((uint32_t)1 << 31)) || while ((win_offset_us & ((uint32_t)1 << 31)) ||
(win_offset_us < conn_offset_us)) { (win_offset_us < conn_offset_us)) {
win_offset_us += conn_interval_us; win_offset_us += conn_interval_us;
} }
*conn_space_us = win_offset_us; *conn_space_us = win_offset_us;
pdu_tx->connect_ind.win_offset = pdu_tx->connect_ind.win_offset =
sys_cpu_to_le16((win_offset_us - conn_offset_us) / sys_cpu_to_le16((win_offset_us - conn_offset_us) /

5
subsys/bluetooth/controller/ll_sw/ull_sched.c
View file

@ -876,7 +876,10 @@ static struct ull_hdr *ull_hdr_get_cb(uint8_t ticker_id, uint32_t *ticks_slot)
conn = ll_conn_get(ticker_id - TICKER_ID_CONN_BASE); conn = ll_conn_get(ticker_id - TICKER_ID_CONN_BASE);
if (conn && !conn->lll.role) { if (conn && !conn->lll.role) {
*ticks_slot = conn->ull.ticks_slot; *ticks_slot =
MAX(conn->ull.ticks_slot,
HAL_TICKER_US_TO_TICKS(
CONFIG_BT_CTLR_CENTRAL_SPACING));
return &conn->ull; return &conn->ull;
} }

6
tests/bluetooth/bsim_bt/bsim_test_multiple/prj.conf
View file

@ -40,6 +40,8 @@ CONFIG_BT_CTLR_RX_BUFFERS=6
# when connected to a single peer device (peripheral_identity sample) have # when connected to a single peer device (peripheral_identity sample) have
# room for window widening and do not overlap with each other in that single # room for window widening and do not overlap with each other in that single
# peer device. This can be tuned based on connection interval and clock # peer device. This can be tuned based on connection interval and clock
# accuracy, current value here is sufficient for 500ppm at 1 second interval. # accuracy, current value here is sufficient for 500ppm at 1 second interval and
# considering required connection event length for 251 byte PDU on 2M PHY.
# (Event Overhead + Radio Ready Delay + Rx window + 1064 + 154 + 1064)
CONFIG_BT_CTLR_ADVANCED_FEATURES=y CONFIG_BT_CTLR_ADVANCED_FEATURES=y
CONFIG_BT_CTLR_SCHED_ADVANCED_CENTRAL_CONN_SPACING=1000 CONFIG_BT_CTLR_CENTRAL_SPACING=3750