uint8_t num_agch(struct gsm_bts_trx *trx, const char * arg)
{
struct gsm_bts *b = trx->bts;
struct gsm48_system_information_type_3 *si3;
if (GSM_BTS_HAS_SI(b, SYSINFO_TYPE_3)) {
si3 = GSM_BTS_SI(b, SYSINFO_TYPE_3);
return si3->control_channel_desc.bs_ag_blks_res;
}
LOGP(DL1P, LOGL_ERROR, "%s: Unable to determine actual BS_AG_BLKS_RES "
"value as SI3 is not available yet, fallback to 1\n", arg);
return 1;
}
/* Apply the rules from 05.02 6.3.1.3 Mapping of BCCH Data */
uint8_t *bts_sysinfo_get(struct gsm_bts *bts, struct gsm_time *g_time)
{
struct gsm_bts_role_bts *btsb = bts_role_bts(bts);
unsigned int tc4_cnt = 0;
unsigned int tc4_sub[4];
/* System information type 2 bis or 2 ter messages are sent if
* needed, as determined by the system operator. If only one of
* them is needed, it is sent when TC = 5. If both are needed,
* 2bis is sent when TC = 5 and 2ter is sent at least once
* within any of 4 consecutive occurrences of TC = 4. */
/* System information type 2 quater is sent if needed, as
* determined by the system operator. If sent on BCCH Norm, it
* shall be sent when TC = 5 if neither of 2bis and 2ter are
* used, otherwise it shall be sent at least once within any of
* 4 consecutive occurrences of TC = 4. If sent on BCCH Ext, it
* is sent at least once within any of 4 consecutive occurrences
* of TC = 5. */
/* System Information type 9 is sent in those blocks with
* TC = 4 which are specified in system information type 3 as
* defined in 3GPP TS 04.08. */
/* System Information Type 13 need only be sent if GPRS support
* is indicated in one or more of System Information Type 3 or 4
* or 7 or 8 messages. These messages also indicate if the
* message is sent on the BCCH Norm or if the message is
* transmitted on the BCCH Ext. In the case that the message is
* sent on the BCCH Norm, it is sent at least once within any of
* 4 consecutive occurrences of TC = 4. */
/* We only implement BCCH Norm at this time */
switch (g_time->tc) {
case 0:
/* System Information Type 1 need only be sent if
* frequency hopping is in use or when the NCH is
* present in a cell. If the MS finds another message
* when TC = 0, it can assume that System Information
* Type 1 is not in use. */
return GSM_BTS_SI(bts, SYSINFO_TYPE_1);
case 1:
/* A SI 2 message will be sent at least every time TC = 1. */
return GSM_BTS_SI(bts, SYSINFO_TYPE_2);
case 2:
return GSM_BTS_SI(bts, SYSINFO_TYPE_3);
case 3:
return GSM_BTS_SI(bts, SYSINFO_TYPE_4);
case 4:
/* iterate over 2ter, 2quater, 9, 13 */
/* determine how many SI we need to send on TC=4,
* and which of them we send when */
if (BTS_HAS_SI(bts, SYSINFO_TYPE_2ter) &&
BTS_HAS_SI(bts, SYSINFO_TYPE_2bis)) {
tc4_sub[tc4_cnt] = SYSINFO_TYPE_2ter;
tc4_cnt += 1;
}
if (BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) &&
(BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) ||
BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))) {
tc4_sub[tc4_cnt] = SYSINFO_TYPE_2quater;
tc4_cnt += 1;
}
if (BTS_HAS_SI(bts, SYSINFO_TYPE_13)) {
tc4_sub[tc4_cnt] = SYSINFO_TYPE_13;
tc4_cnt += 1;
}
if (BTS_HAS_SI(bts, SYSINFO_TYPE_9)) {
/* FIXME: check SI3 scheduling info! */
tc4_sub[tc4_cnt] = SYSINFO_TYPE_9;
tc4_cnt += 1;
}
/* simply send SI2 if we have nothing else to send */
if (tc4_cnt == 0)
return GSM_BTS_SI(bts, SYSINFO_TYPE_2);
else {
/* increment static counter by one, modulo count */
btsb->si.tc4_ctr = (btsb->si.tc4_ctr + 1) % tc4_cnt;
return GSM_BTS_SI(bts, tc4_sub[btsb->si.tc4_ctr]);
}
case 5:
/* 2bis, 2ter, 2quater */
if (BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) &&
!BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))
return GSM_BTS_SI(bts, SYSINFO_TYPE_2bis);
else if (BTS_HAS_SI(bts, SYSINFO_TYPE_2ter) &&
!BTS_HAS_SI(bts, SYSINFO_TYPE_2bis))
return GSM_BTS_SI(bts, SYSINFO_TYPE_2ter);
else if (BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) &&
BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))
return GSM_BTS_SI(bts, SYSINFO_TYPE_2bis);
else if (BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) &&
!BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) &&
!BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))
return GSM_BTS_SI(bts, SYSINFO_TYPE_2quater);
break;
case 6:
return GSM_BTS_SI(bts, SYSINFO_TYPE_3);
case 7:
return GSM_BTS_SI(bts, SYSINFO_TYPE_4);
}
return NULL;
}
