/* ITU-T G.964 Section 14.3.3 V5.1-intterface Layer 1 FSM - AN and LE */

/* (C) 2022 by Andreas Eversberg <jolly@eversberg.eu>
 *
 * All Rights Reserved
 *
 * SPDX-License-Identifier: GPL-2.0+
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

/***********************************************************************/
/* internal data structures */
/***********************************************************************/

#include <errno.h>

#include <osmocom/core/linuxlist.h>
#include <osmocom/gsm/tlv.h>

#include "v5x_internal.h"
#include "v5x_protocol.h"
#include "v52_le_lcp_fsm.h"
#include "layer1.h"
#include "v5x_l1_fsm.h"
#include "logging.h"

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

#define TIMEOUT 1

/***********************************************************************/
/* state names, event names, primitives, ... */
/***********************************************************************/

enum v5x_l1_fsm_state {
	V5X_L1FSM_S_ANLE1_NORMAL,
	V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL,
	V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL,
	V5X_L1FSM_S_ANLE4_INTERNAL_FAIL,
	V5X_L1FSM_S_ANLE51_LINK_ID_SENDING,
	V5X_L1FSM_S_ANLE52_LINK_ID_RECEIVED,
};

enum v5x_l1_fsm_event {
	/* V5.x events */
	V5X_L1FSM_E_MPH_stop,	/* Request to stop with error report */
	V5X_L1FSM_E_MPH_proceed,/* Request to proceed with error report */
	V5X_L1FSM_E_NORMAL,	/* Normal frames, Sa7 == 1 */
	V5X_L1FSM_E_LOS,	/* Loss of signal/frame */
	V5X_L1FSM_E_RAI,	/* Remote alarm indication */
	V5X_L1FSM_E_AIS,	/* Alarm indication signal */
	V5X_L1FSM_E_INTERNAL_F,	/* Internal failure */
	V5X_L1FSM_E_INTERNAL_D,	/* Internal failure disappears */
	V5X_L1FSM_E_TIMEOUT,	/* Persistence check timer fired */
	/* V5.2 events */
	V5X_L1FSM_E_MPH_ID,	/* Send link identification signal */
	V5X_L1FSM_E_MPH_NOR,	/* Remove link identification signal */
	V5X_L1FSM_E_MPH_IDR,	/* Link identification request */
	V5X_L1FSM_E_NORMAL_Sa7,	/* Normal frames, Sa7 == 0 */
};

static const struct value_string v5x_l1_fsm_event_names[] = {
	{ V5X_L1FSM_E_MPH_stop,		"Request to stop with error report" },
	{ V5X_L1FSM_E_MPH_proceed,	"Request to proceed with error report" },
	{ V5X_L1FSM_E_NORMAL,		"Normal frames, Sa7 = ONE" },
	{ V5X_L1FSM_E_LOS,		"Loss of signal/frame" },
	{ V5X_L1FSM_E_RAI,		"Remote alarm indication" },
	{ V5X_L1FSM_E_AIS,		"Alarm indication signal" },
	{ V5X_L1FSM_E_INTERNAL_F,	"Internal failure" },
	{ V5X_L1FSM_E_INTERNAL_D,	"Internal failure disappears" },
	{ V5X_L1FSM_E_TIMEOUT,		"Expiry of persistence check timer" },
	{ V5X_L1FSM_E_MPH_ID,		"Send link identification signal" },
	{ V5X_L1FSM_E_MPH_NOR,		"Remove link identification signal" },
	{ V5X_L1FSM_E_MPH_IDR,		"Link identification request" },
	{ V5X_L1FSM_E_NORMAL_Sa7,	"Normal frames, Sa7 = ZERO" },
	{ 0, NULL }
};

/***********************************************************************/
/* Messages to other layers */
/***********************************************************************/

/* send message to upper (LCP) layer */
static void mph_rcv(struct osmo_fsm_inst *fi, enum v5x_mph_prim prim)
{
	struct v5x_l1_proto *l1 = fi->priv;
	struct v5x_link *v5l = l1->v5l;

	if (v5l->fi)
		v52_le_lcp_mph_rcv(v5l, prim);
	// FIXME: send to other protocols too
}

static void signal_snd(struct osmo_fsm_inst *fi, enum l1_signal_prim prim)
{
	struct v5x_l1_proto *l1 = fi->priv;
	struct v5x_link *v5l = l1->v5l;

	v5x_l1_signal_snd(v5l, prim);
}

/***********************************************************************/
/* L1 state FSM */
/***********************************************************************/

static int v5x_l1_fsm_timer_cb(struct osmo_fsm_inst *fi)
{
	osmo_fsm_inst_dispatch(fi, V5X_L1FSM_E_TIMEOUT, NULL);

	return 0;
}

static void l1_fsm_le1_normal(struct osmo_fsm_inst *fi, uint32_t event, void __attribute__((unused)) *data)
{
	switch (event) {
	case V5X_L1FSM_E_NORMAL:
		/* ignore */
		break;
	case V5X_L1FSM_E_LOS:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL, TIMEOUT, 0);
		/* send MPH-EIa */
		mph_rcv(fi, MPH_EIa);
		break;
	case V5X_L1FSM_E_RAI:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL, TIMEOUT, 0);
		/* send MPH-EIb */
		mph_rcv(fi, MPH_EIb);
		break;
	case V5X_L1FSM_E_AIS:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL, TIMEOUT, 0);
		/* send MPH-EIc */
		mph_rcv(fi, MPH_EIc);
		break;
	case V5X_L1FSM_E_INTERNAL_F:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE4_INTERNAL_FAIL, 0, 0);
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		/* send MPH-EId */
		mph_rcv(fi, MPH_EId);
		break;
	case V5X_L1FSM_E_TIMEOUT:
		/* send MPH-AI */
		mph_rcv(fi, MPH_AI);
		break;
	case V5X_L1FSM_E_MPH_ID:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE51_LINK_ID_SENDING, 0, 0);
		/* send Sa7 = ZERO */
		signal_snd(fi, L1_SIGNAL_SA7_0);
		break;
	case V5X_L1FSM_E_MPH_NOR:
		/* ignore */
		break;
	case V5X_L1FSM_E_NORMAL_Sa7:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE52_LINK_ID_RECEIVED, 0, 0);
		break;
	case V5X_L1FSM_E_MPH_IDR:
		/* send MPH-EIg */
		mph_rcv(fi, MPH_EIg);
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static void l1_fsm_le2_locally_det_fail(struct osmo_fsm_inst *fi, uint32_t event, void __attribute__((unused)) *data)
{
	switch (event) {
	case V5X_L1FSM_E_NORMAL:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE1_NORMAL, TIMEOUT, 0);
		break;
	case V5X_L1FSM_E_LOS:
		/* send MPH-EIa */
		mph_rcv(fi, MPH_EIa);
		break;
	case V5X_L1FSM_E_RAI:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL, 0, 0);
		/* send MPH-EIdr */
		mph_rcv(fi, MPH_EIdr);
		/* send MPH-EIb */
		mph_rcv(fi, MPH_EIb);
		break;
	case V5X_L1FSM_E_AIS:
		/* send MPH-EIc */
		mph_rcv(fi, MPH_EIc);
		break;
	case V5X_L1FSM_E_INTERNAL_F:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE4_INTERNAL_FAIL, 0, 0);
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		/* send MPH-EId */
		mph_rcv(fi, MPH_EId);
		break;
	case V5X_L1FSM_E_TIMEOUT:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	case V5X_L1FSM_E_MPH_ID:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	case V5X_L1FSM_E_MPH_NOR:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	case V5X_L1FSM_E_NORMAL_Sa7:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE52_LINK_ID_RECEIVED, TIMEOUT, 0);
		break;
	case V5X_L1FSM_E_MPH_IDR:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static void l1_fsm_le3_remotely_det_fail(struct osmo_fsm_inst *fi, uint32_t event, void __attribute__((unused)) *data)
{
	switch (event) {
	case V5X_L1FSM_E_NORMAL:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE1_NORMAL, TIMEOUT, 0);
		break;
	case V5X_L1FSM_E_LOS:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL, 0, 0);
		/* send MPH-EIa */
		mph_rcv(fi, MPH_EIa);
		/* send MPH-EIbr */
		mph_rcv(fi, MPH_EIbr);
		break;
	case V5X_L1FSM_E_RAI:
		/* ignore */
		break;
	case V5X_L1FSM_E_AIS:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL, 0, 0);
		/* send MPH-EIc */
		mph_rcv(fi, MPH_EIc);
		/* send MPH-EIbr */
		mph_rcv(fi, MPH_EIbr);
		break;
	case V5X_L1FSM_E_INTERNAL_F:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE4_INTERNAL_FAIL, 0, 0);
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		/* send MPH-EId */
		mph_rcv(fi, MPH_EId);
		break;
	case V5X_L1FSM_E_TIMEOUT:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	case V5X_L1FSM_E_MPH_ID:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	case V5X_L1FSM_E_MPH_NOR:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	case V5X_L1FSM_E_NORMAL_Sa7:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE52_LINK_ID_RECEIVED, TIMEOUT, 0);
		break;
	case V5X_L1FSM_E_MPH_IDR:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static void l1_fsm_le4_internal_fail(struct osmo_fsm_inst *fi, uint32_t event, void __attribute__((unused)) *data)
{
	struct v5x_link *v5l = fi->priv;
	struct v5x_l1_proto *l1 = v5l->l1;

	switch (event) {
	case V5X_L1FSM_E_NORMAL:
		/* ignore */
		break;
	case V5X_L1FSM_E_LOS:
		/* send MPH-EIa */
		mph_rcv(fi, MPH_EIa);
		break;
	case V5X_L1FSM_E_RAI:
		/* ignore */
		break;
	case V5X_L1FSM_E_AIS:
		/* send MPH-EIc */
		mph_rcv(fi, MPH_EIc);
		break;
	case V5X_L1FSM_E_INTERNAL_F:
		/* ignore */
		break;
	case V5X_L1FSM_E_INTERNAL_D:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL, 0, 0);
		/* send MPH-EIbr */
		mph_rcv(fi, MPH_EIbr);
		/* Go on to normal state, when no alarm persists.
		 * We must do this, because there is no frame reception to trigger this.
		 */
		if (!l1->los && !l1->rai && !l1->ais) {
			if (l1->sa7 == 0)
				osmo_fsm_inst_dispatch(fi, V5X_L1FSM_E_NORMAL_Sa7, NULL);
			else
				osmo_fsm_inst_dispatch(fi, V5X_L1FSM_E_NORMAL, NULL);
		}
		break;
	case V5X_L1FSM_E_TIMEOUT:
		/* ignore */
		break;
	case V5X_L1FSM_E_MPH_ID:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	case V5X_L1FSM_E_MPH_NOR:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	case V5X_L1FSM_E_NORMAL_Sa7:
		/* ignore */
		break;
	case V5X_L1FSM_E_MPH_IDR:
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static void l1_fsm_le51_link_id_sending(struct osmo_fsm_inst *fi, uint32_t event, void __attribute__((unused)) *data)
{
	switch (event) {
	case V5X_L1FSM_E_NORMAL:
		/* ignore */
		break;
	case V5X_L1FSM_E_LOS:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL, TIMEOUT, 0);
		/* send Sa7 = ONE */
		signal_snd(fi, L1_SIGNAL_SA7_1);
		/* send MPH-EIa */
		mph_rcv(fi, MPH_EIa);
		break;
	case V5X_L1FSM_E_RAI:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL, TIMEOUT, 0);
		/* send Sa7 = ONE */
		signal_snd(fi, L1_SIGNAL_SA7_1);
		/* send MPH-EIb */
		mph_rcv(fi, MPH_EIb);
		break;
	case V5X_L1FSM_E_AIS:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL, TIMEOUT, 0);
		/* send Sa7 = ONE */
		signal_snd(fi, L1_SIGNAL_SA7_1);
		/* send MPH-EIc */
		mph_rcv(fi, MPH_EIc);
		break;
	case V5X_L1FSM_E_INTERNAL_F:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE4_INTERNAL_FAIL, 0, 0);
		/* send Sa7 = ONE */
		signal_snd(fi, L1_SIGNAL_SA7_1);
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		/* send MPH-EId */
		mph_rcv(fi, MPH_EId);
		break;
	case V5X_L1FSM_E_MPH_ID:
		/* ignore */
		break;
	case V5X_L1FSM_E_MPH_NOR:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE1_NORMAL, 0, 0);
		/* send Sa7 = ONE */
		signal_snd(fi, L1_SIGNAL_SA7_1);
		break;
	case V5X_L1FSM_E_NORMAL_Sa7:
		/* ignore */
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static void l1_fsm_le52_link_id_received(struct osmo_fsm_inst *fi, uint32_t event, void __attribute__((unused)) *data)
{
	switch (event) {
	case V5X_L1FSM_E_NORMAL:
		break;
	case V5X_L1FSM_E_LOS:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL, TIMEOUT, 0);
		/* send MPH-EIa */
		mph_rcv(fi, MPH_EIa);
		break;
	case V5X_L1FSM_E_RAI:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL, TIMEOUT, 0);
		/* send MPH-EIb */
		mph_rcv(fi, MPH_EIb);
		break;
	case V5X_L1FSM_E_AIS:
		/* Start timer */
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL, TIMEOUT, 0);
		/* send MPH-EIc */
		mph_rcv(fi, MPH_EIc);
		break;
	case V5X_L1FSM_E_INTERNAL_F:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE4_INTERNAL_FAIL, 0, 0);
		/* send MPH-DI */
		mph_rcv(fi, MPH_DI);
		/* send MPH-EId */
		mph_rcv(fi, MPH_EId);
		break;
	case V5X_L1FSM_E_TIMEOUT:
		/* send MPH-DI */
		mph_rcv(fi, MPH_AI);
		break;
	case V5X_L1FSM_E_MPH_ID:
		osmo_fsm_inst_state_chg(fi, V5X_L1FSM_S_ANLE51_LINK_ID_SENDING, 0, 0);
		/* send Sa7 = ZERO */
		signal_snd(fi, L1_SIGNAL_SA7_0);
		break;
	case V5X_L1FSM_E_NORMAL_Sa7:
		/* ignore */
		break;
	case V5X_L1FSM_E_MPH_IDR:
		/* send MPH-IDI */
		mph_rcv(fi, MPH_IDI);
		break;
	default:
		OSMO_ASSERT(0);
	}
}

/* Table 12/G.965 */
static const struct osmo_fsm_state v5x_l1_fsm_states[] = {
	[V5X_L1FSM_S_ANLE1_NORMAL] = {
		.name = "AN/LE1 Normal",
		.in_event_mask = S(V5X_L1FSM_E_NORMAL) |
				 S(V5X_L1FSM_E_LOS) |
				 S(V5X_L1FSM_E_RAI) |
				 S(V5X_L1FSM_E_AIS) |
				 S(V5X_L1FSM_E_INTERNAL_F) |
				 S(V5X_L1FSM_E_TIMEOUT) |
				 S(V5X_L1FSM_E_MPH_ID) |
				 S(V5X_L1FSM_E_MPH_NOR) |
				 S(V5X_L1FSM_E_NORMAL_Sa7) |
				 S(V5X_L1FSM_E_MPH_IDR),
		.out_state_mask = S(V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL) |
				  S(V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL) |
				  S(V5X_L1FSM_S_ANLE4_INTERNAL_FAIL) |
				  S(V5X_L1FSM_S_ANLE51_LINK_ID_SENDING) |
				  S(V5X_L1FSM_S_ANLE52_LINK_ID_RECEIVED),
		.action = l1_fsm_le1_normal,
	},
	[V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL] = {
		.name = "AN/LE2 Locally detected failure",
		.in_event_mask = S(V5X_L1FSM_E_NORMAL) |
				 S(V5X_L1FSM_E_LOS) |
				 S(V5X_L1FSM_E_RAI) |
				 S(V5X_L1FSM_E_AIS) |
				 S(V5X_L1FSM_E_INTERNAL_F) |
				 S(V5X_L1FSM_E_TIMEOUT) |
				 S(V5X_L1FSM_E_MPH_ID) |
				 S(V5X_L1FSM_E_MPH_NOR) |
				 S(V5X_L1FSM_E_NORMAL_Sa7) |
				 S(V5X_L1FSM_E_MPH_IDR),
		.out_state_mask = S(V5X_L1FSM_S_ANLE1_NORMAL) |
				  S(V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL) |
				  S(V5X_L1FSM_S_ANLE4_INTERNAL_FAIL) |
				  S(V5X_L1FSM_S_ANLE52_LINK_ID_RECEIVED),
		.action = l1_fsm_le2_locally_det_fail,
	},
	[V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL] = {
		.name = "AN/LE3 Remotely detected failure",
		.in_event_mask = S(V5X_L1FSM_E_NORMAL) |
				 S(V5X_L1FSM_E_LOS) |
				 S(V5X_L1FSM_E_RAI) |
				 S(V5X_L1FSM_E_AIS) |
				 S(V5X_L1FSM_E_INTERNAL_F) |
				 S(V5X_L1FSM_E_TIMEOUT) |
				 S(V5X_L1FSM_E_MPH_ID) |
				 S(V5X_L1FSM_E_MPH_NOR) |
				 S(V5X_L1FSM_E_NORMAL_Sa7) |
				 S(V5X_L1FSM_E_MPH_IDR),
		.out_state_mask = S(V5X_L1FSM_S_ANLE1_NORMAL) |
				  S(V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL) |
				  S(V5X_L1FSM_S_ANLE4_INTERNAL_FAIL) |
				  S(V5X_L1FSM_S_ANLE52_LINK_ID_RECEIVED),
		.action = l1_fsm_le3_remotely_det_fail,
	},
	[V5X_L1FSM_S_ANLE4_INTERNAL_FAIL] = {
		.name = "AN/LE4 Internal failure",
		.in_event_mask = S(V5X_L1FSM_E_NORMAL) |
				 S(V5X_L1FSM_E_LOS) |
				 S(V5X_L1FSM_E_RAI) |
				 S(V5X_L1FSM_E_AIS) |
				 S(V5X_L1FSM_E_INTERNAL_F) |
				 S(V5X_L1FSM_E_INTERNAL_D) |
				 S(V5X_L1FSM_E_TIMEOUT) |
				 S(V5X_L1FSM_E_MPH_ID) |
				 S(V5X_L1FSM_E_MPH_NOR) |
				 S(V5X_L1FSM_E_NORMAL_Sa7) |
				 S(V5X_L1FSM_E_MPH_IDR),
		.out_state_mask = S(V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL),
		.action = l1_fsm_le4_internal_fail,
	},
	[V5X_L1FSM_S_ANLE51_LINK_ID_SENDING] = {
		.name = "AN/LE5.1 Link ID sending",
		.in_event_mask = S(V5X_L1FSM_E_NORMAL) |
				 S(V5X_L1FSM_E_LOS) |
				 S(V5X_L1FSM_E_RAI) |
				 S(V5X_L1FSM_E_AIS) |
				 S(V5X_L1FSM_E_INTERNAL_F) |
				 S(V5X_L1FSM_E_MPH_ID) |
				 S(V5X_L1FSM_E_MPH_NOR) |
				 S(V5X_L1FSM_E_NORMAL_Sa7),
		.out_state_mask = S(V5X_L1FSM_S_ANLE1_NORMAL) |
				  S(V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL) |
				  S(V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL) |
				  S(V5X_L1FSM_S_ANLE4_INTERNAL_FAIL),
		.action = l1_fsm_le51_link_id_sending,
	},
	[V5X_L1FSM_S_ANLE52_LINK_ID_RECEIVED] = {
		.name = "AN/LE5.2 Link ID received",
		.in_event_mask = S(V5X_L1FSM_E_NORMAL) |
				 S(V5X_L1FSM_E_LOS) |
				 S(V5X_L1FSM_E_RAI) |
				 S(V5X_L1FSM_E_AIS) |
				 S(V5X_L1FSM_E_INTERNAL_F) |
				 S(V5X_L1FSM_E_TIMEOUT) |
				 S(V5X_L1FSM_E_MPH_ID) |
				 S(V5X_L1FSM_E_NORMAL_Sa7) |
				 S(V5X_L1FSM_E_MPH_IDR),
		.out_state_mask = S(V5X_L1FSM_S_ANLE1_NORMAL) |
				  S(V5X_L1FSM_S_ANLE2_LOCALLY_DET_FAIL) |
				  S(V5X_L1FSM_S_ANLE3_REMOTELY_DET_FAIL) |
				  S(V5X_L1FSM_S_ANLE4_INTERNAL_FAIL) |
				  S(V5X_L1FSM_S_ANLE51_LINK_ID_SENDING),
		.action = l1_fsm_le52_link_id_received,
	},
};

struct osmo_fsm v5x_l1_fsm = {
	.name = "V5X_L1",
	.states = v5x_l1_fsm_states,
	.num_states = ARRAY_SIZE(v5x_l1_fsm_states),
	.timer_cb = v5x_l1_fsm_timer_cb,
	.log_subsys = DV5L1,
	.event_names = v5x_l1_fsm_event_names,
};

struct v5x_l1_proto *v5x_l1_fsm_create(void *ctx, struct v5x_link *v5l, uint8_t id)
{
	struct v5x_l1_proto *l1;

	OSMO_ASSERT(v5l);

	l1 = talloc_zero(ctx, struct v5x_l1_proto);
	if (!l1)
		return NULL;
	l1->v5l = v5l;
	l1->sa7 = -1;

	l1->fi = osmo_fsm_inst_alloc(&v5x_l1_fsm, l1, l1, LOGL_DEBUG, NULL);
	if (!l1->fi)
		return NULL;
	osmo_fsm_inst_update_id_f(l1->fi, "%s-L%u", v5x_interface_name(v5l->interface), id);

	return l1;
}

void v5x_l1_fsm_destroy(struct v5x_l1_proto *l1)
{
	if (l1->fi) {
		osmo_fsm_inst_free(l1->fi);
	}

	talloc_free(l1);
}

const char *v5x_l1_fsm_state_name(struct v5x_l1_proto *l1)
{
	return v5x_l1_fsm_states[l1->fi->state].name;
}

void v5x_l1_init(void)
{
	int rc;

	rc = osmo_fsm_register(&v5x_l1_fsm);
	OSMO_ASSERT(!rc);
	LOGP(DV5L1, LOGL_NOTICE, "Using V5x L1 protocol\n");
}

bool v5x_l1_is_up(struct v5x_l1_proto *l1)
{
	return l1->fi->state == V5X_L1FSM_S_ANLE1_NORMAL
	    || l1->fi->state == V5X_L1FSM_S_ANLE51_LINK_ID_SENDING
	    || l1->fi->state == V5X_L1FSM_S_ANLE52_LINK_ID_RECEIVED;
}

/***********************************************************************
 * Messages from other layers
 ***********************************************************************/

/* receive primitive from physical E1 layer */
int v5x_l1_signal_rcv(struct v5x_link *v5l, enum l1_signal_prim prim)
{
	struct v5x_l1_proto *l1 = v5l->l1;
	struct v5x_interface *v5if = v5l->interface;
	struct osmo_fsm_inst *fi = l1->fi;
	int state_changed = 0;

	switch (prim) {
	case L1_SIGNAL_LOS:
		LOGV5L(v5l, DV5L1, LOGL_DEBUG, "Signal LOS detected on link %d of interface %d.\n", v5l->id, v5if->id);
		if (!l1->los) {
			l1->los = 1;
			osmo_fsm_inst_dispatch(fi, V5X_L1FSM_E_LOS, NULL);
		}
		break;
	case L1_SIGNAL_NO_LOS:
		LOGV5L(v5l, DV5L1, LOGL_DEBUG, "Signal LOS gone on link %d of interface %d.\n", v5l->id, v5if->id);
		if (l1->los) {
			l1->los = 0;
			state_changed = 1;
		}
		break;
	case L1_SIGNAL_RAI:
		LOGV5L(v5l, DV5L1, LOGL_DEBUG, "Signal RAI detected on link %d of interface %d.\n", v5l->id, v5if->id);
		if (!l1->rai) {
			l1->rai = 1;
			osmo_fsm_inst_dispatch(fi, V5X_L1FSM_E_RAI, NULL);
		}
		break;
	case L1_SIGNAL_NO_RAI:
		LOGV5L(v5l, DV5L1, LOGL_DEBUG, "Signal RAI gone on link %d of interface %d.\n", v5l->id, v5if->id);
		if (l1->rai) {
			l1->rai = 0;
			state_changed = 1;
		}
		break;
	case L1_SIGNAL_AIS:
		LOGV5L(v5l, DV5L1, LOGL_DEBUG, "Signal AIS detected on link %d of interface %d.\n", v5l->id, v5if->id);
		if (!l1->ais) {
			l1->ais = 1;
			osmo_fsm_inst_dispatch(fi, V5X_L1FSM_E_AIS, NULL);
		}
		break;
	case L1_SIGNAL_NO_AIS:
		LOGV5L(v5l, DV5L1, LOGL_DEBUG, "Signal AIS gone on link %d of interface %d.\n", v5l->id, v5if->id);
		if (l1->ais) {
			l1->ais = 0;
			state_changed = 1;
		}
		break;
	case L1_SIGNAL_SA7_0:

		if (l1->sa7 != 0) {
			LOGV5L(v5l, DV5L1, LOGL_DEBUG, "Bit Sa7=0 on link %d of interface %d.\n", v5l->id, v5if->id);
			l1->sa7 = 0;
			state_changed = 1;
		}
		break;
	case L1_SIGNAL_SA7_1:
		if (l1->sa7 != 1) {
			LOGV5L(v5l, DV5L1, LOGL_DEBUG, "Bit Sa7=1 on link %d of interface %d.\n", v5l->id, v5if->id);
			l1->sa7 = 1;
			state_changed = 1;
		}
		break;
	default:
		LOGV5L(v5l, DV5L1, LOGL_NOTICE, "Invalid L1 primitive %d receied from physical layer.\n", prim);
		return -EINVAL;
	}

	/* Go on to normal state, when no alarm persists.
	 * We must do this, because there is no frame reception to trigger this.
	 */
	if (state_changed && !l1->los && !l1->rai && !l1->ais) {
		if (l1->sa7 == 0)
			osmo_fsm_inst_dispatch(fi, V5X_L1FSM_E_NORMAL_Sa7, NULL);
		else
			osmo_fsm_inst_dispatch(fi, V5X_L1FSM_E_NORMAL, NULL);
	}

        return 0;
}

/* receive message from upper (LCP) layer */
void v5x_l1_mph_snd(struct v5x_link *v5l, enum v5x_mph_prim prim)
{
	struct v5x_l1_proto *l1 = v5l->l1;
	enum v5x_l1_fsm_event event;

	switch (prim) {
	case MPH_ID:
		event = V5X_L1FSM_E_MPH_ID;
		break;
	case MPH_NOR:
		event = V5X_L1FSM_E_MPH_NOR;
		break;
	case MPH_IDR:
		event = V5X_L1FSM_E_MPH_IDR;
		break;
	case MPH_stop:
		// FIXME: do we need this?
		break;
	case MPH_proceed:
		// FIXME: do we need this?
		break;
	default:
		LOGV5L(v5l, DV5PORT, LOGL_NOTICE, "Got invalid prim %d at this protocol\n", prim);
		return;
	}

	/* send event to FSM */
	osmo_fsm_inst_dispatch(l1->fi, event, NULL);
}