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osmo-pcu
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PTCCH: implement basic message codec and API 

Change-Id: Id79e95aafdde4a71977c64385fce48b729a51ca9
Related: OS#1545
This commit is contained in:
Vadim Yanitskiy 2019-10-05 21:57:14 +07:00
parent 0bf622e057
commit bd0dac3783
3 changed files with 54 additions and 0 deletions
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1
src/bts.cpp
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@ -252,6 +252,7 @@ BTS::BTS()
for (size_t ts_no = 0; ts_no < ARRAY_SIZE(trx->pdch); ++ts_no) {
struct gprs_rlcmac_pdch *pdch = &trx->pdch[ts_no];
pdch->init_ptcch_msg();
pdch->ts_no = ts_no;
pdch->trx = trx;
}

35
src/pdch.cpp
View File

@ -48,6 +48,7 @@ extern "C" {
}
#include <errno.h>
#include <stdlib.h>
#include <arpa/inet.h>
extern void *tall_pcu_ctx;
@ -961,3 +962,37 @@ inline gprs_rlcmac_bts *gprs_rlcmac_pdch::bts_data() const
{
return trx->bts->bts_data();
}
/* PTCCH (Packet Timing Advance Control Channel) */
void gprs_rlcmac_pdch::init_ptcch_msg(void)
{
memset(ptcch_msg, PTCCH_TAI_FREE, PTCCH_TAI_NUM);
memset(ptcch_msg + PTCCH_TAI_NUM, PTCCH_PADDING, 7);
}
uint8_t gprs_rlcmac_pdch::reserve_tai(uint8_t ta)
{
uint8_t tai;
for (tai = 0; tai < PTCCH_TAI_NUM; tai++) {
if (ptcch_msg[tai] == PTCCH_TAI_FREE) {
ptcch_msg[tai] = ta;
return tai;
}
}
/* Special case: no free TAI available */
return PTCCH_TAI_FREE;
}
void gprs_rlcmac_pdch::release_tai(uint8_t tai)
{
OSMO_ASSERT(tai < PTCCH_TAI_NUM);
ptcch_msg[tai] = PTCCH_TAI_FREE;
}
void gprs_rlcmac_pdch::update_ta(uint8_t tai, uint8_t ta)
{
OSMO_ASSERT(tai < PTCCH_TAI_NUM);
ptcch_msg[tai] = ta;
}

18
src/pdch.h
View File

@ -35,6 +35,11 @@ extern "C" {
#include <stdint.h>
/* PTCCH (Packet Timing Advance Control Channel) */
#define PTCCH_TAI_FREE 0x7f /*!< Special value for unused TA Indexes */
#define PTCCH_TAI_NUM 16 /*!< Number of PTCCH/U slots and thus TA Indexes */
#define PTCCH_PADDING 0x2b /*!< PTCCH/D messages need to be padded to 23 octets */
/*
* PDCH instance
*/
@ -88,6 +93,19 @@ struct gprs_rlcmac_pdch {
struct llist_head paging_list; /* list of paging messages */
uint32_t last_rts_fn; /* store last frame number of RTS */
/* PTCCH (Packet Timing Advance Control Channel) */
uint8_t ptcch_msg[GSM_MACBLOCK_LEN]; /* 'ready to use' PTCCH/D message */
#ifdef __cplusplus
/* Initialize the PTCCH/D message */
void init_ptcch_msg(void);
/* Obtain an unused TA Index for a TBF */
uint8_t reserve_tai(uint8_t ta);
/* Mark a given TA Index as free, so it can be used again */
void release_tai(uint8_t tai);
/* Update the actual Timing Advance value for a given TA Index */
void update_ta(uint8_t tai, uint8_t ta);
#endif
/* back pointers */
struct gprs_rlcmac_trx *trx;
uint8_t ts_no;