osmocom-bb/src/host/trxcon/src/trxcon_fsm.c

/*
 * OsmocomBB <-> SDR connection bridge
 *
 * (C) 2022 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
 * Author: Vadim Yanitskiy <vyanitskiy@sysmocom.de>
 *
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 */

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

#include <arpa/inet.h>

#include <osmocom/core/fsm.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/talloc.h>

#include <osmocom/bb/trxcon/trxcon.h>
#include <osmocom/bb/trxcon/trx_if.h>
#include <osmocom/bb/trxcon/logging.h>
#include <osmocom/bb/trxcon/l1ctl.h>
#include <osmocom/bb/trxcon/l1ctl_server.h>
#include <osmocom/bb/trxcon/l1ctl_proto.h>
#include <osmocom/bb/l1sched/l1sched.h>

#define S(x)	(1 << (x))

static void trxcon_allstate_action(struct osmo_fsm_inst *fi,
				   uint32_t event, void *data)
{
	struct trxcon_inst *trxcon = fi->priv;

	switch (event) {
	case TRXCON_EV_L1IF_FAILURE:
	case TRXCON_EV_L2IF_FAILURE:
		LOGPFSML(fi, LOGL_NOTICE, "Event %s is not handled\n",
			 osmo_fsm_event_name(&trxcon_fsm_def, event));
		/* TODO: osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL); */
		break;
	case TRXCON_EV_RESET_FULL_REQ:
		if (fi->state != TRXCON_ST_RESET)
			osmo_fsm_inst_state_chg(fi, TRXCON_ST_RESET, 0, 0);
		l1sched_reset(trxcon->sched, true);
		trx_if_cmd_poweroff(trxcon->phyif);
		trx_if_cmd_echo(trxcon->phyif);
		break;
	case TRXCON_EV_RESET_SCHED_REQ:
		l1sched_reset(trxcon->sched, false);
		break;
	case TRXCON_EV_SET_CONFIG_REQ:
	{
		const struct trxcon_param_set_config_req *req = data;

		if (trxcon->l1p.ta != req->timing_advance)
			trx_if_cmd_setta(trxcon->phyif, req->timing_advance);
		trxcon->l1p.tx_power = req->tx_power;
		trxcon->l1p.ta = req->timing_advance;
		break;
	}
	default:
		OSMO_ASSERT(0);
	}
}

static int trxcon_timer_cb(struct osmo_fsm_inst *fi)
{
	struct trxcon_inst *trxcon = fi->priv;

	switch (fi->state) {
	case TRXCON_ST_FBSB_SEARCH:
		l1ctl_tx_fbsb_fail(trxcon->l2if, trxcon->l1p.band_arfcn);
		osmo_fsm_inst_state_chg(fi, TRXCON_ST_RESET, 0, 0);
		return 0;
	default:
		OSMO_ASSERT(0);
	}
}

static void trxcon_st_reset_action(struct osmo_fsm_inst *fi,
				   uint32_t event, void *data)
{
	struct trxcon_inst *trxcon = fi->priv;

	switch (event) {
	case TRXCON_EV_FBSB_SEARCH_REQ:
	{
		const struct trxcon_param_fbsb_search_req *req = data;
		const struct trx_instance *trx = trxcon->phyif;

		osmo_fsm_inst_state_chg_ms(fi, TRXCON_ST_FBSB_SEARCH, req->timeout_ms, 0);

		l1sched_configure_ts(trxcon->sched, 0, req->pchan_config);

		/* Only if current ARFCN differs */
		if (trxcon->l1p.band_arfcn != req->band_arfcn) {
			/* Update current ARFCN */
			trxcon->l1p.band_arfcn = req->band_arfcn;

			/* Tune transceiver to required ARFCN */
			trx_if_cmd_rxtune(trxcon->phyif, req->band_arfcn);
			trx_if_cmd_txtune(trxcon->phyif, req->band_arfcn);
		}

		/* Transceiver might have been powered on before, e.g.
		 * in case of sending L1CTL_FBSB_REQ due to signal loss. */
		if (!trx->powered_up)
			trx_if_cmd_poweron(trxcon->phyif);
		break;
	}
	case TRXCON_EV_FULL_POWER_SCAN_REQ:
	{
		const struct trxcon_param_full_power_scan_req *req = data;

		osmo_fsm_inst_state_chg(fi, TRXCON_ST_FULL_POWER_SCAN, 0, 0); /* TODO: timeout */
		trx_if_cmd_measure(trxcon->phyif, req->band_arfcn_start, req->band_arfcn_stop);
		break;
	}
	default:
		OSMO_ASSERT(0);
	}
}

static void trxcon_st_full_power_scan_action(struct osmo_fsm_inst *fi,
					     uint32_t event, void *data)
{
	struct trxcon_inst *trxcon = fi->priv;

	switch (event) {
	case TRXCON_EV_FULL_POWER_SCAN_RES:
	{
		const struct trxcon_param_full_power_scan_res *res = data;

		l1ctl_tx_pm_conf(trxcon->l2if, res->band_arfcn, res->dbm, res->last_result);
		break;
	}
	default:
		OSMO_ASSERT(0);
	}
}

static void trxcon_st_fbsb_search_action(struct osmo_fsm_inst *fi,
					 uint32_t event, void *data)
{
	struct trxcon_inst *trxcon = fi->priv;

	switch (event) {
	case TRXCON_EV_FBSB_SEARCH_RES:
		osmo_fsm_inst_state_chg(fi, TRXCON_ST_BCCH_CCCH, 0, 0);
		l1ctl_tx_fbsb_conf(trxcon->l2if,
				   trxcon->l1p.band_arfcn,
				   trxcon->sched->bsic);
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static void handle_tx_access_burst_req(struct osmo_fsm_inst *fi,
				       const struct trxcon_param_tx_access_burst_req *req)
{
	struct trxcon_inst *trxcon = fi->priv;
	enum l1sched_ts_prim_type prim_type;
	const struct l1sched_ts_prim *prim;

	const struct l1sched_ts_prim_rach rach = {
		.synch_seq = req->synch_seq,
		.offset = req->offset,
		.ra = req->ra,
	};

	prim_type = req->is_11bit ? L1SCHED_PRIM_RACH11 : L1SCHED_PRIM_RACH8;
	prim = l1sched_prim_push(trxcon->sched, prim_type,
				 req->chan_nr, req->link_id,
				 (const uint8_t *)&rach, sizeof(rach));
	if (prim == NULL)
		LOGPFSML(fi, LOGL_ERROR, "Failed to enqueue a prim\n");
}

static void trxcon_st_bcch_ccch_action(struct osmo_fsm_inst *fi,
				       uint32_t event, void *data)
{
	struct trxcon_inst *trxcon = fi->priv;
	struct l1sched_ts *ts;
	int rc;

	switch (event) {
	case TRXCON_EV_TX_ACCESS_BURST_REQ:
		handle_tx_access_burst_req(fi, data);
		break;
	case TRXCON_EV_SET_CCCH_MODE_REQ:
	{
		struct trxcon_param_set_ccch_tch_mode_req *req = data;
		enum gsm_phys_chan_config chan_config = req->mode;

		/* Make sure that TS0 is allocated and configured */
		ts = trxcon->sched->ts[0];
		if (ts == NULL || ts->mf_layout == NULL) {
			LOGPFSML(fi, LOGL_ERROR, "TS0 is not configured\n");
			return;
		}

		/* Do nothing if the current mode matches required */
		if (ts->mf_layout->chan_config != chan_config)
			l1sched_configure_ts(trxcon->sched, 0, chan_config);
		req->applied = true;
		break;
	}
	case TRXCON_EV_DEDICATED_ESTABLISH_REQ:
	{
		const struct trxcon_param_dedicated_establish_req *req = data;
		enum gsm_phys_chan_config config;

		config = l1sched_chan_nr2pchan_config(req->chan_nr);
		if (config == GSM_PCHAN_NONE) {
			LOGPFSML(fi, LOGL_ERROR, "Failed to determine channel config\n");
			return;
		}

		if (req->hopping) {
			/* Apply the freq. hopping parameters */
			rc = trx_if_cmd_setfh(trxcon->phyif,
					      req->h1.hsn, req->h1.maio,
					      &req->h1.ma[0], req->h1.n);
			if (rc)
				return;

			/* Set current ARFCN to an invalid value */
			trxcon->l1p.band_arfcn = 0xffff;
		} else {
			/* Tune transceiver to required ARFCN */
			if (trx_if_cmd_rxtune(trxcon->phyif, req->h0.band_arfcn))
				return;
			if (trx_if_cmd_txtune(trxcon->phyif, req->h0.band_arfcn))
				return;

			/* Update current ARFCN */
			trxcon->l1p.band_arfcn = req->h0.band_arfcn;
		}

		rc = l1sched_configure_ts(trxcon->sched, req->chan_nr & 0x07, config);
		if (rc)
			return;
		ts = trxcon->sched->ts[req->chan_nr & 0x07];
		OSMO_ASSERT(ts != NULL);

		l1sched_deactivate_all_lchans(ts);

		/* Activate only requested lchans */
		rc = l1sched_set_lchans(ts, req->chan_nr, 1, req->tch_mode, req->tsc);
		if (rc) {
			LOGPFSML(fi, LOGL_ERROR, "Failed to activate requested lchans\n");
			return;
		}

		osmo_fsm_inst_state_chg(fi, TRXCON_ST_DEDICATED, 0, 0);
		break;
	}
	case TRXCON_EV_RX_DATA_IND:
	{
		const struct trxcon_param_rx_traffic_data_ind *ind = data;
		const struct l1ctl_info_dl dl_hdr = {
			.chan_nr = ind->chan_nr,
			.link_id = ind->link_id,
			.frame_nr = htonl(ind->frame_nr),
			.band_arfcn = htons(trxcon->l1p.band_arfcn),
			.fire_crc = ind->data_len > 0 ? 0 : 2,
			.rx_level = dbm2rxlev(ind->rssi),
			.num_biterr = ind->n_errors,
			/* TODO: set proper .snr */
		};

		l1ctl_tx_dt_ind(trxcon->l2if, &dl_hdr, ind->data, ind->data_len, false);
		break;
	}
	default:
		OSMO_ASSERT(0);
	}
}

static void trxcon_st_dedicated_action(struct osmo_fsm_inst *fi,
				       uint32_t event, void *data)
{
	struct trxcon_inst *trxcon = fi->priv;

	switch (event) {
	case TRXCON_EV_TX_ACCESS_BURST_REQ:
		handle_tx_access_burst_req(fi, data);
		break;
	case TRXCON_EV_DEDICATED_RELEASE_REQ:
		l1sched_reset(trxcon->sched, false);
		osmo_fsm_inst_state_chg(fi, TRXCON_ST_RESET, 0, 0);
		break;
	case TRXCON_EV_SET_TCH_MODE_REQ:
	{
		struct trxcon_param_set_ccch_tch_mode_req *req = data;
		unsigned int tn;

		/* Iterate over timeslot list */
		for (tn = 0; tn < ARRAY_SIZE(trxcon->sched->ts); tn++) {
			struct l1sched_ts *ts = trxcon->sched->ts[tn];
			struct l1sched_lchan_state *lchan;

			/* Timeslot is not allocated */
			if (ts == NULL || ts->mf_layout == NULL)
				continue;

			/* Iterate over all allocated lchans */
			llist_for_each_entry(lchan, &ts->lchans, list) {
				/* Omit inactive channels */
				if (!lchan->active)
					continue;
				lchan->tch_mode = req->mode;
				req->applied = true;
			}
		}
		break;
	}
	case TRXCON_EV_CRYPTO_REQ:
	{
		const struct trxcon_param_crypto_req *req = data;
		unsigned int tn = req->chan_nr & 0x07;
		struct l1sched_ts *ts;

		/* Make sure that required TS is allocated and configured */
		ts = trxcon->sched->ts[tn];
		if (ts == NULL || ts->mf_layout == NULL) {
			LOGPFSML(fi, LOGL_ERROR, "TS%u is not configured\n", tn);
			return;
		}

		if (l1sched_start_ciphering(ts, req->a5_algo, req->key, req->key_len) != 0) {
			LOGPFSML(fi, LOGL_ERROR, "Failed to configure ciphering\n");
			return;
		}
		break;
	}
	case TRXCON_EV_TX_TRAFFIC_REQ:
	case TRXCON_EV_TX_DATA_REQ:
	{
		const struct trxcon_param_tx_traffic_data_req *req = data;
		struct l1sched_ts_prim *prim;

		prim = l1sched_prim_push(trxcon->sched, L1SCHED_PRIM_DATA,
					 req->chan_nr, req->link_id,
					 req->data, req->data_len);
		if (prim == NULL) {
			LOGPFSML(fi, LOGL_ERROR, "Failed to enqueue a prim\n");
			return;
		}
		break;
	}
	case TRXCON_EV_RX_TRAFFIC_IND:
	case TRXCON_EV_RX_DATA_IND:
	{
		const struct trxcon_param_rx_traffic_data_ind *ind = data;
		const struct l1ctl_info_dl dl_hdr = {
			.chan_nr = ind->chan_nr,
			.link_id = ind->link_id,
			.frame_nr = htonl(ind->frame_nr),
			.band_arfcn = htons(trxcon->l1p.band_arfcn),
			.fire_crc = ind->data_len > 0 ? 0 : 2,
			.rx_level = dbm2rxlev(ind->rssi),
			.num_biterr = ind->n_errors,
			/* TODO: set proper .snr */
		};

		l1ctl_tx_dt_ind(trxcon->l2if, &dl_hdr,
				ind->data, ind->data_len,
				event == TRXCON_EV_RX_TRAFFIC_IND);
		break;
	}
	default:
		OSMO_ASSERT(0);
	}
}

static const struct osmo_fsm_state trxcon_fsm_states[] = {
	[TRXCON_ST_RESET] = {
		.name = "RESET",
		.out_state_mask = S(TRXCON_ST_FBSB_SEARCH)
				| S(TRXCON_ST_FULL_POWER_SCAN),
		.in_event_mask  = S(TRXCON_EV_FBSB_SEARCH_REQ)
				| S(TRXCON_EV_FULL_POWER_SCAN_REQ),
		.action = &trxcon_st_reset_action,
	},
	[TRXCON_ST_FULL_POWER_SCAN] = {
		.name = "FULL_POWER_SCAN",
		.out_state_mask = S(TRXCON_ST_RESET),
		.in_event_mask  = S(TRXCON_EV_FULL_POWER_SCAN_RES),
		.action = &trxcon_st_full_power_scan_action,
	},
	[TRXCON_ST_FBSB_SEARCH] = {
		.name = "FBSB_SEARCH",
		.out_state_mask = S(TRXCON_ST_RESET)
				| S(TRXCON_ST_BCCH_CCCH),
		.in_event_mask  = S(TRXCON_EV_FBSB_SEARCH_RES),
		.action = &trxcon_st_fbsb_search_action,
	},
	[TRXCON_ST_BCCH_CCCH] = {
		.name = "BCCH_CCCH",
		.out_state_mask = S(TRXCON_ST_RESET)
				| S(TRXCON_ST_FBSB_SEARCH)
				| S(TRXCON_ST_DEDICATED),
		.in_event_mask  = S(TRXCON_EV_RX_DATA_IND)
				| S(TRXCON_EV_SET_CCCH_MODE_REQ)
				| S(TRXCON_EV_TX_ACCESS_BURST_REQ)
				| S(TRXCON_EV_DEDICATED_ESTABLISH_REQ),
		.action = &trxcon_st_bcch_ccch_action,
	},
	[TRXCON_ST_DEDICATED] = {
		.name = "DEDICATED",
		.out_state_mask = S(TRXCON_ST_RESET)
				| S(TRXCON_ST_FBSB_SEARCH)
				| S(TRXCON_ST_BCCH_CCCH),
		.in_event_mask  = S(TRXCON_EV_DEDICATED_RELEASE_REQ)
				| S(TRXCON_EV_TX_ACCESS_BURST_REQ)
				| S(TRXCON_EV_SET_TCH_MODE_REQ)
				| S(TRXCON_EV_TX_TRAFFIC_REQ)
				| S(TRXCON_EV_RX_TRAFFIC_IND)
				| S(TRXCON_EV_TX_DATA_REQ)
				| S(TRXCON_EV_RX_DATA_IND)
				| S(TRXCON_EV_CRYPTO_REQ),
		.action = &trxcon_st_dedicated_action,
	},
};

static const struct value_string trxcon_fsm_event_names[] = {
	OSMO_VALUE_STRING(TRXCON_EV_L1IF_FAILURE),
	OSMO_VALUE_STRING(TRXCON_EV_L2IF_FAILURE),
	OSMO_VALUE_STRING(TRXCON_EV_RESET_FULL_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_RESET_SCHED_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_FULL_POWER_SCAN_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_FULL_POWER_SCAN_RES),
	OSMO_VALUE_STRING(TRXCON_EV_FBSB_SEARCH_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_FBSB_SEARCH_RES),
	OSMO_VALUE_STRING(TRXCON_EV_SET_CCCH_MODE_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_SET_TCH_MODE_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_SET_CONFIG_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_TX_ACCESS_BURST_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_DEDICATED_ESTABLISH_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_DEDICATED_RELEASE_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_TX_TRAFFIC_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_RX_TRAFFIC_IND),
	OSMO_VALUE_STRING(TRXCON_EV_TX_DATA_REQ),
	OSMO_VALUE_STRING(TRXCON_EV_RX_DATA_IND),
	OSMO_VALUE_STRING(TRXCON_EV_CRYPTO_REQ),
	{ 0, NULL }
};

struct osmo_fsm trxcon_fsm_def = {
	.name = "trxcon",
	.states = trxcon_fsm_states,
	.num_states = ARRAY_SIZE(trxcon_fsm_states),
	.log_subsys = DAPP,
	.event_names = trxcon_fsm_event_names,
	.allstate_event_mask = S(TRXCON_EV_L1IF_FAILURE)
			     | S(TRXCON_EV_L2IF_FAILURE)
			     | S(TRXCON_EV_RESET_FULL_REQ)
			     | S(TRXCON_EV_RESET_SCHED_REQ)
			     | S(TRXCON_EV_SET_CONFIG_REQ),
	.allstate_action = &trxcon_allstate_action,
	.timer_cb = &trxcon_timer_cb,
};

static __attribute__((constructor)) void on_dso_load(void)
{
	OSMO_ASSERT(osmo_fsm_register(&trxcon_fsm_def) == 0);
}