diff options
| author | Vadim Yanitskiy <vyanitskiy@sysmocom.de> | 2023-06-22 23:00:05 +0700 |
|---|---|---|
| committer | fixeria <vyanitskiy@sysmocom.de> | 2023-06-25 08:45:26 +0000 |
| commit | 418d76c2cb72704a2f65a5d7e1718d9d097ace7d (patch) | |
| tree | d9d286d0ab0f4dedf5b81f68338eef40b07a48da | |
| parent | 315e78aab152631a52d9c0d92963ba1f90b8b9f5 (diff) | |
gsm: add gsm0502_fn2ccch_block()
This API is useful for checking whether a Downlink CCCH block belongs
to PCH or AGCH. We need this API in osmo-bts.git and osmocom-bb.git.
Change-Id: I8cbd31226754e95887358ed83a928e2f567f4cf3
Related: OS#5500
| -rw-r--r-- | include/osmocom/gsm/gsm0502.h | 2 | ||||
| -rw-r--r-- | src/gsm/gsm0502.c | 35 | ||||
| -rw-r--r-- | src/gsm/libosmogsm.map | 1 |
3 files changed, 38 insertions, 0 deletions
diff --git a/include/osmocom/gsm/gsm0502.h b/include/osmocom/gsm/gsm0502.h index ac697d99..43ab0b8f 100644 --- a/include/osmocom/gsm/gsm0502.h +++ b/include/osmocom/gsm/gsm0502.h @@ -105,3 +105,5 @@ uint32_t gsm0502_fn_remap(uint32_t fn, enum gsm0502_fn_remap_channel channel); uint16_t gsm0502_hop_seq_gen(const struct gsm_time *t, uint8_t hsn, uint8_t maio, size_t n, const uint16_t *ma); + +int gsm0502_fn2ccch_block(uint32_t fn); diff --git a/src/gsm/gsm0502.c b/src/gsm/gsm0502.c index b1474061..e9e612ab 100644 --- a/src/gsm/gsm0502.c +++ b/src/gsm/gsm0502.c @@ -260,3 +260,38 @@ uint16_t gsm0502_hop_seq_gen(const struct gsm_time *t, return ma ? ma[mai] : mai; } + +#define CB_FCCH -1 +#define CB_SCH -2 +#define CB_BCCH -3 +#define CB_IDLE -4 + +/* Clause 7 Table 3 and Figure 8a */ +static const int ccch_block_table[51] = { + CB_FCCH, CB_SCH, /* 0..1 */ + CB_BCCH, CB_BCCH, CB_BCCH, CB_BCCH, /* 2..5: BCCH */ + 0, 0, 0, 0, /* 6..9: B0 */ + CB_FCCH, CB_SCH, /* 10..11 */ + 1, 1, 1, 1, /* 12..15: B1 */ + 2, 2, 2, 2, /* 16..19: B2 */ + CB_FCCH, CB_SCH, /* 20..21 */ + 3, 3, 3, 3, /* 22..25: B3 */ + 4, 4, 4, 4, /* 26..29: B4 */ + CB_FCCH, CB_SCH, /* 30..31 */ + 5, 5, 5, 5, /* 32..35: B5 */ + 6, 6, 6, 6, /* 36..39: B6 */ + CB_FCCH, CB_SCH, /* 40..41 */ + 7, 7, 7, 7, /* 42..45: B7 */ + 8, 8, 8, 8, /* 46..49: B8 */ + CB_IDLE /* 50: Idle */ +}; + +/*! Calculate CCCH block number from the given TDMA frame number. + * \param[in] fn TDMA frame number (of first or last burst). + * \returns CCCH block number 0..8 or a negative value, + * if the given frame number cannot carry CCCH. + */ +int gsm0502_fn2ccch_block(uint32_t fn) +{ + return ccch_block_table[fn % 51]; +} diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map index 1e5a7b20..609ee7e0 100644 --- a/src/gsm/libosmogsm.map +++ b/src/gsm/libosmogsm.map @@ -111,6 +111,7 @@ gsm0480_gen_reject; gsm0502_calc_paging_group; gsm0502_fn_remap; gsm0502_hop_seq_gen; +gsm0502_fn2ccch_block; gsm0503_xcch; gsm0503_rach; |