egprs: Add CPS tables from TS 04.60

Includes EGPRS coding and puncturing scheme (CPS) tables from 3GPP
TS 04.60. Currently osmo-bts-trx is the only user of CPS table
values, but this may change with gprsdecode and other utilities.

Change-Id: I09fe6514a0e2e51bb3206f8387633f7e0255345f
diff --git a/include/osmocom/gprs/gprs_rlc.h b/include/osmocom/gprs/gprs_rlc.h
new file mode 100644
index 0000000..d34d49b
--- /dev/null
+++ b/include/osmocom/gprs/gprs_rlc.h
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <stdint.h>
+
+/*! \brief Structure for CPS coding and puncturing scheme (TS 04.60 10.4.8a) */
+struct egprs_cps {
+	uint8_t bits;
+	uint8_t mcs;
+	uint8_t p[2];
+};
+
+/*! \brief CPS puncturing table selection (TS 04.60 10.4.8a) */
+enum egprs_cps_punc {
+	EGPRS_CPS_P1,
+	EGPRS_CPS_P2,
+	EGPRS_CPS_P3,
+	EGPRS_CPS_NONE = -1,
+};
+
+/*! \brief EGPRS header types (TS 04.60 10.0a.2) */
+enum egprs_hdr_type {
+        EGPRS_HDR_TYPE1,
+        EGPRS_HDR_TYPE2,
+        EGPRS_HDR_TYPE3,
+};
+
+int egprs_get_cps(struct egprs_cps *cps, uint8_t type, uint8_t bits);