/* Common routines for the TETRA PHY/MAC implementation */

/* (C) 2011 by Harald Welte <laforge@gnumonks.org>
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */


#include <stdint.h>
#include <string.h>

#include <osmocom/core/utils.h>
#include <osmocom/core/bits.h>

#include "tetra_common.h"
#include "tetra_prim.h"

uint32_t bits_to_uint(const uint8_t *bits, unsigned int len)
{
	uint32_t ret = 0;

	while (len--)
		ret = (ret << 1) | (*bits++ & 1);

	return ret;
}

static inline uint32_t tetra_band_base_hz(uint8_t band)
{
	return (band * 100000000);
}

static const int16_t tetra_carrier_offset[4] = {
	[0] =	     0,
	[1] =	  6250,
	[2] =	 -6250,
	[3] =	+12500,
};

uint32_t tetra_dl_carrier_hz(uint8_t band, uint16_t carrier, uint8_t offset)
{
	uint32_t freq = tetra_band_base_hz(band);
	freq += carrier * 25000;
	freq += tetra_carrier_offset[offset&3];
	return freq;
}

/* TS 100 392-15, Table 2 */
static const int16_t tetra_duplex_spacing[8][16] = { /* values are in kHz */
	[0] = { -1, 1600, 10000, 10000, 10000, 10000, 10000, -1, -1, -1, -1, -1, -1, -1, -1, -1 },
	[1] = { -1, 4500, -1, 36000, 7000, -1, -1, -1, 45000, 45000, -1, -1, -1, -1, -1, -1 },
	[2] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
	[3] = { -1, -1, -1, 8000, 8000, -1, -1, -1, 18000, 18000, -1, -1, -1, -1, -1, -1 },
	[4] = { -1, -1, -1, 18000, 5000, -1, 30000, 30000, -1, 39000, -1, -1, -1, -1, -1, -1 },
	[5] = { -1, -1, -1, -1, 9500, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 },
	[6] = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 },
	[7] = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 },
};

uint32_t tetra_ul_carrier_hz(uint8_t band, uint16_t carrier, uint8_t offset,
			     uint8_t duplex, uint8_t reverse)
{
	uint32_t freq = tetra_dl_carrier_hz(band, carrier, offset);

	uint32_t duplex_spacing = tetra_duplex_spacing[duplex & 7][band & 15];

	if (duplex_spacing < 0) /* reserved for future standardization */
	    return 0;

	duplex_spacing *= 1000; // make Hz

	if (reverse)
	    freq += duplex_spacing;
	else
	    freq -= duplex_spacing;

	return freq;
}

static const struct value_string tetra_sap_names[] = {
	{ TETRA_SAP_TP,		"TP-SAP" },
	{ TETRA_SAP_TMV,	"TMV-SAP" },
	{ TETRA_SAP_TMA,	"TMA-SAP" },
	{ TETRA_SAP_TMB,	"TMB-SAP" },
	{ TETRA_SAP_TMD,	"TMD-SAP" },
	{ 0, NULL }
};

static const struct value_string tetra_lchan_names[] = {
	{ TETRA_LC_UNKNOWN,	"UNKNOWN" },
	{ TETRA_LC_SCH_F,	"SCH/F" },
	{ TETRA_LC_SCH_HD,	"SCH/HD" },
	{ TETRA_LC_SCH_HU,	"SCH/HU" },
	{ TETRA_LC_STCH,	"STCH" },
	{ TETRA_LC_SCH_P8_F,	"SCH-P8/F" },
	{ TETRA_LC_SCH_P8_HD,	"SCH-P8/HD" },
	{ TETRA_LC_SCH_P8_HU,	"SCH-P8/HU" },
	{ TETRA_LC_AACH,	"AACH" },
	{ TETRA_LC_TCH,		"TCH" },
	{ TETRA_LC_BSCH,	"BSCH" },
	{ TETRA_LC_BNCH,	"BNCH" },
	{ 0, NULL }
};

const char *tetra_get_lchan_name(enum tetra_log_chan lchan)
{
	return get_value_string(tetra_lchan_names, lchan);
}

const char *tetra_get_sap_name(uint8_t sap)
{
	return get_value_string(tetra_sap_names, sap);
}

void tetra_mac_state_init(struct tetra_mac_state *tms)
{
	INIT_LLIST_HEAD(&tms->voice_channels);
}