laforge has submitted this change. ( https://gerrit.osmocom.org/c/osmo-bsc/+/27618 )

Change subject: fix gsm_bts_get_cbch(): CBCH can be allocated on Cn ......................................................................

fix gsm_bts_get_cbch(): CBCH can be allocated on Cn

According to 3GPP TS 45.002, table 3, unlike the CCCH+SDCCH/4+CBCH combination, which can only be allocated on C0/TS0, the SDCCH/8+CBCH can be allocated on C0..n/TS0..3. In other words, having CBCH on e.g. TRX1/C1 is perfectly legal. This is why in gsm_bts_get_cbch() we should check all transceivers, not just the C0.

Change-Id: Ie79ccff4f8f0f1134757ec0c35e18b58081cc158 Related: SYS#5905 --- M src/osmo-bsc/bts.c 1 file changed, 11 insertions(+), 10 deletions(-)

Approvals: laforge: Looks good to me, approved Jenkins Builder: Verified

diff --git a/src/osmo-bsc/bts.c b/src/osmo-bsc/bts.c index d09aa48..843d711 100644 --- a/src/osmo-bsc/bts.c +++ b/src/osmo-bsc/bts.c @@ -562,22 +562,23 @@ /* return the gsm_lchan for the CBCH (if it exists at all) */ struct gsm_lchan *gsm_bts_get_cbch(struct gsm_bts *bts) { - struct gsm_lchan *lchan = NULL; struct gsm_bts_trx *trx = bts->c0;

+ /* According to 3GPP TS 45.002, table 3, CBCH can be allocated + * either on C0/TS0 (CCCH+SDCCH4) or on C0..n/TS0..3 (SDCCH/8). */ if (trx->ts[0].pchan_from_config == GSM_PCHAN_CCCH_SDCCH4_CBCH) - lchan = &trx->ts[0].lchan[2]; - else { - int i; - for (i = 0; i < 8; i++) { - if (trx->ts[i].pchan_from_config == GSM_PCHAN_SDCCH8_SACCH8C_CBCH) { - lchan = &trx->ts[i].lchan[2]; - break; - } + return &trx->ts[0].lchan[2]; /* C0/TS0 */ + + llist_for_each_entry(trx, &bts->trx_list, list) { /* C0..n */ + unsigned int tn; + for (tn = 0; tn < 4; tn++) { /* TS0..3 */ + struct gsm_bts_trx_ts *ts = &trx->ts[tn]; + if (ts->pchan_from_config == GSM_PCHAN_SDCCH8_SACCH8C_CBCH) + return &ts->lchan[2]; } }

- return lchan; + return NULL; }

int gsm_set_bts_type(struct gsm_bts *bts, enum gsm_bts_type type)