gsm0808_utils: fix gsm48 multirate configuration generator
The function gsm0808_sc_cfg_from_gsm48_mr_cfg() takes an S15 to S0
bitmask and converts that bitmask into an AMR multirate configuration
struct.
Unfortunately the current implementation implements 3GPP TS 28.062,
Table 7.11.3.1.3-2 wrongly in some aspects. Lets fix this.
- Fix wrong interpretation of the bitpatterns
- 5,15K is invalid and must never be selected
- Make sure that no more than 4 rates are selected in the active set
- Extend unit-test
Change-Id: I6fd7f4073b84093742c322752f2fd878d1071e15
Related: SYS#4470
diff --git a/include/osmocom/gsm/gsm0808_utils.h b/include/osmocom/gsm/gsm0808_utils.h
index 53f145c..dedb029 100644
--- a/include/osmocom/gsm/gsm0808_utils.h
+++ b/include/osmocom/gsm/gsm0808_utils.h
@@ -130,7 +130,7 @@
int gsm0808_speech_codec_from_chan_type(struct gsm0808_speech_codec *sc,
uint8_t perm_spch);
uint16_t gsm0808_sc_cfg_from_gsm48_mr_cfg(const struct gsm48_multi_rate_conf *cfg, bool fr);
-void gsm48_mr_cfg_from_gsm0808_sc_cfg(struct gsm48_multi_rate_conf *cfg, uint16_t s15_s0);
+int gsm48_mr_cfg_from_gsm0808_sc_cfg(struct gsm48_multi_rate_conf *cfg, uint16_t s15_s0);
/*! \returns 3GPP TS 08.08 §3.2.2.5 Class of a given Cause */
static inline enum gsm0808_cause_class gsm0808_cause_class(enum gsm0808_cause cause)