// SPDX-License-Identifier: GPL-2.0-or-later
/******************************************************************************
 *
 *      (C)Copyright 1998,1999 SysKonnect,
 *      a business unit of Schneider & Koch & Co. Datensysteme GmbH.
 *
 *      See the file "skfddi.c" for further information.
 *
 *      The information in this file is provided "AS IS" without warranty.
 *
 ******************************************************************************/

/*
        SMT RMT
        Ring Management
*/

/*
 * Hardware independent state machine implemantation
 * The following external SMT functions are referenced :
 *
 *              queue_event()
 *              smt_timer_start()
 *              smt_timer_stop()
 *
 *      The following external HW dependent functions are referenced :
 *              sm_ma_control()
 *              sm_mac_check_beacon_claim()
 *
 *      The following HW dependent events are required :
 *              RM_RING_OP
 *              RM_RING_NON_OP
 *              RM_MY_BEACON
 *              RM_OTHER_BEACON
 *              RM_MY_CLAIM
 *              RM_TRT_EXP
 *              RM_VALID_CLAIM
 *
 */

#include "h/types.h"
#include "h/fddi.h"
#include "h/smc.h"

#define KERNEL
#include "h/smtstate.h"

/*
 * FSM Macros
 */
#define AFLAG   0x10
#define GO_STATE(x)     (smc->mib.m[MAC0].fddiMACRMTState = (x)|AFLAG)
#define ACTIONS_DONE()  (smc->mib.m[MAC0].fddiMACRMTState &= ~AFLAG)
#define ACTIONS(x)      (x|AFLAG)

#define RM0_ISOLATED    0
#define RM1_NON_OP      1               /* not operational */
#define RM2_RING_OP     2               /* ring operational */
#define RM3_DETECT      3               /* detect dupl addresses */
#define RM4_NON_OP_DUP  4               /* dupl. addr detected */
#define RM5_RING_OP_DUP 5               /* ring oper. with dupl. addr */
#define RM6_DIRECTED    6               /* sending directed beacons */
#define RM7_TRACE       7               /* trace initiated */

/*
 * symbolic state names
 */
static const char * const rmt_states[] = {
        "RM0_ISOLATED","RM1_NON_OP","RM2_RING_OP","RM3_DETECT",
        "RM4_NON_OP_DUP","RM5_RING_OP_DUP","RM6_DIRECTED",
        "RM7_TRACE"
} ;

/*
 * symbolic event names
 */
static const char * const rmt_events[] = {
        "NONE","RM_RING_OP","RM_RING_NON_OP","RM_MY_BEACON",
        "RM_OTHER_BEACON","RM_MY_CLAIM","RM_TRT_EXP","RM_VALID_CLAIM",
        "RM_JOIN","RM_LOOP","RM_DUP_ADDR","RM_ENABLE_FLAG",
        "RM_TIMEOUT_NON_OP","RM_TIMEOUT_T_STUCK",
        "RM_TIMEOUT_ANNOUNCE","RM_TIMEOUT_T_DIRECT",
        "RM_TIMEOUT_D_MAX","RM_TIMEOUT_POLL","RM_TX_STATE_CHANGE"
} ;

/*
 * Globals
 * in struct s_rmt
 */


/*
 * function declarations
 */
static void rmt_fsm(struct s_smc *smc, int cmd);
static void start_rmt_timer0(struct s_smc *smc, u_long value, int event);
static void start_rmt_timer1(struct s_smc *smc, u_long value, int event);
static void start_rmt_timer2(struct s_smc *smc, u_long value, int event);
static void stop_rmt_timer0(struct s_smc *smc);
static void stop_rmt_timer1(struct s_smc *smc);
static void stop_rmt_timer2(struct s_smc *smc);
static void rmt_dup_actions(struct s_smc *smc);
static void rmt_reinsert_actions(struct s_smc *smc);
static void rmt_leave_actions(struct s_smc *smc);
static void rmt_new_dup_actions(struct s_smc *smc);

#ifndef SUPERNET_3
extern void restart_trt_for_dbcn() ;
#endif /*SUPERNET_3*/

/*
        init RMT state machine
        clear all RMT vars and flags
*/
void rmt_init(struct s_smc *smc)
{
        smc->mib.m[MAC0].fddiMACRMTState = ACTIONS(RM0_ISOLATED) ;
        smc->r.dup_addr_test = DA_NONE ;
        smc->r.da_flag = 0 ;
        smc->mib.m[MAC0].fddiMACMA_UnitdataAvailable = FALSE ;
        smc->r.sm_ma_avail = FALSE ;
        smc->r.loop_avail = 0 ;
        smc->r.bn_flag = 0 ;
        smc->r.jm_flag = 0 ;
        smc->r.no_flag = TRUE ;
}

/*
        RMT state machine
        called by dispatcher

        do
                display state change
                process event
        until SM is stable
*/
void rmt(struct s_smc *smc, int event)
{
        int     state ;

        do {
                DB_RMT("RMT : state %s%s event %s",
                       smc->mib.m[MAC0].fddiMACRMTState & AFLAG ? "ACTIONS " : "",
                       rmt_states[smc->mib.m[MAC0].fddiMACRMTState & ~AFLAG],
                       rmt_events[event]);
                state = smc->mib.m[MAC0].fddiMACRMTState ;
                rmt_fsm(smc,event) ;
                event = 0 ;
        } while (state != smc->mib.m[MAC0].fddiMACRMTState) ;
        rmt_state_change(smc,(int)smc->mib.m[MAC0].fddiMACRMTState) ;
}

/*
        process RMT event
*/
static void rmt_fsm(struct s_smc *smc, int cmd)
{
        /*
         * RM00-RM70 : from all states
         */
        if (!smc->r.rm_join && !smc->r.rm_loop &&
                smc->mib.m[MAC0].fddiMACRMTState != ACTIONS(RM0_ISOLATED) &&
                smc->mib.m[MAC0].fddiMACRMTState != RM0_ISOLATED) {
                RS_SET(smc,RS_NORINGOP) ;
                rmt_indication(smc,0) ;
                GO_STATE(RM0_ISOLATED) ;
                return ;
        }

        switch(smc->mib.m[MAC0].fddiMACRMTState) {
        case ACTIONS(RM0_ISOLATED) :
                stop_rmt_timer0(smc) ;
                stop_rmt_timer1(smc) ;
                stop_rmt_timer2(smc) ;

                /*
                 * Disable MAC.
                 */
                sm_ma_control(smc,MA_OFFLINE) ;
                smc->mib.m[MAC0].fddiMACMA_UnitdataAvailable = FALSE ;
                smc->r.loop_avail = FALSE ;
                smc->r.sm_ma_avail = FALSE ;
                smc->r.no_flag = TRUE ;
                DB_RMTN(1, "RMT : ISOLATED");
                ACTIONS_DONE() ;
                break ;
        case RM0_ISOLATED :
                /*RM01*/
                if (smc->r.rm_join || smc->r.rm_loop) {
                        /*
                         * According to the standard the MAC must be reset
                         * here. The FORMAC will be initialized and Claim
                         * and Beacon Frames will be uploaded to the MAC.
                         * So any change of Treq will take effect NOW.
                         */
                        sm_ma_control(smc,MA_RESET) ;
                        GO_STATE(RM1_NON_OP) ;
                        break ;
                }
                break ;
        case ACTIONS(RM1_NON_OP) :
                start_rmt_timer0(smc,smc->s.rmt_t_non_op,RM_TIMEOUT_NON_OP) ;
                stop_rmt_timer1(smc) ;
                stop_rmt_timer2(smc) ;
                sm_ma_control(smc,MA_BEACON) ;
                DB_RMTN(1, "RMT : RING DOWN");
                RS_SET(smc,RS_NORINGOP) ;
                smc->r.sm_ma_avail = FALSE ;
                rmt_indication(smc,0) ;
                ACTIONS_DONE() ;
                break ;
        case RM1_NON_OP :
                /*RM12*/
                if (cmd == RM_RING_OP) {
                        RS_SET(smc,RS_RINGOPCHANGE) ;
                        GO_STATE(RM2_RING_OP) ;
                        break ;
                }
                /*RM13*/
                else if (cmd == RM_TIMEOUT_NON_OP) {
                        smc->r.bn_flag = FALSE ;
                        smc->r.no_flag = TRUE ;
                        GO_STATE(RM3_DETECT) ;
                        break ;
                }
                break ;
        case ACTIONS(RM2_RING_OP) :
                stop_rmt_timer0(smc) ;
                stop_rmt_timer1(smc) ;
                stop_rmt_timer2(smc) ;
                smc->r.no_flag = FALSE ;
                if (smc->r.rm_loop)
                        smc->r.loop_avail = TRUE ;
                if (smc->r.rm_join) {
                        smc->r.sm_ma_avail = TRUE ;
                        if (smc->mib.m[MAC0].fddiMACMA_UnitdataEnable)
                                smc->mib.m[MAC0].fddiMACMA_UnitdataAvailable = TRUE;
                        else
                                smc->mib.m[MAC0].fddiMACMA_UnitdataAvailable = FALSE;
                }
                DB_RMTN(1, "RMT : RING UP");
                RS_CLEAR(smc,RS_NORINGOP) ;
                RS_SET(smc,RS_RINGOPCHANGE) ;
                rmt_indication(smc,1) ;
                smt_stat_counter(smc,0) ;
                ACTIONS_DONE() ;
                break ;
        case RM2_RING_OP :
                /*RM21*/
                if (cmd == RM_RING_NON_OP) {
                        smc->mib.m[MAC0].fddiMACMA_UnitdataAvailable = FALSE ;
                        smc->r.loop_avail = FALSE ;
                        RS_SET(smc,RS_RINGOPCHANGE) ;
                        GO_STATE(RM1_NON_OP) ;
                        break ;
                }
                /*RM22a*/
                else if (cmd == RM_ENABLE_FLAG) {
                        if (smc->mib.m[MAC0].fddiMACMA_UnitdataEnable)
                        smc->mib.m[MAC0].fddiMACMA_UnitdataAvailable = TRUE ;
                                else
                        smc->mib.m[MAC0].fddiMACMA_UnitdataAvailable = FALSE ;
                }
                /*RM25*/
                else if (smc->r.dup_addr_test == DA_FAILED) {
                        smc->mib.m[MAC0].fddiMACMA_UnitdataAvailable = FALSE ;
                        smc->r.loop_avail = FALSE ;
                        smc->r.da_flag = TRUE ;
                        GO_STATE(RM5_RING_OP_DUP) ;
                        break ;
                }
                break ;
        case ACTIONS(RM3_DETECT) :
                start_rmt_timer0(smc,smc->s.mac_d_max*2,RM_TIMEOUT_D_MAX) ;
                start_rmt_timer1(smc,smc->s.rmt_t_stuck,RM_TIMEOUT_T_STUCK) ;
                start_rmt_timer2(smc,smc->s.rmt_t_poll,RM_TIMEOUT_POLL) ;
                sm_mac_check_beacon_claim(smc) ;
                DB_RMTN(1, "RMT : RM3_DETECT");
                ACTIONS_DONE() ;
                break ;
        case RM3_DETECT :
                if (cmd == RM_TIMEOUT_POLL) {
                        start_rmt_timer2(smc,smc->s.rmt_t_poll,RM_TIMEOUT_POLL);
                        sm_mac_check_beacon_claim(smc) ;
                        break ;
                }
                if (cmd == RM_TIMEOUT_D_MAX) {
                        smc->r.timer0_exp = TRUE ;
                }
                /*
                 *jd(22-Feb-1999)
                 * We need a time ">= 2*mac_d_max" since we had finished
                 * Claim or Beacon state. So we will restart timer0 at
                 * every state change.
                 */
                if (cmd == RM_TX_STATE_CHANGE) {
                        start_rmt_timer0(smc,
                                         smc->s.mac_d_max*2,
                                         RM_TIMEOUT_D_MAX) ;
                }
                /*RM32*/
                if (cmd == RM_RING_OP) {
                        GO_STATE(RM2_RING_OP) ;
                        break ;
                }
                /*RM33a*/
                else if ((cmd == RM_MY_BEACON || cmd == RM_OTHER_BEACON)
                        && smc->r.bn_flag) {
                        smc->r.bn_flag = FALSE ;
                }
                /*RM33b*/
                else if (cmd == RM_TRT_EXP && !smc->r.bn_flag) {
                        int     tx ;
                        /*
                         * set bn_flag only if in state T4 or T5:
                         * only if we're the beaconer should we start the
                         * trace !
                         */
                        if ((tx =  sm_mac_get_tx_state(smc)) == 4 || tx == 5) {
                        DB_RMTN(2, "RMT : DETECT && TRT_EXPIRED && T4/T5");
                                smc->r.bn_flag = TRUE ;
                                /*
                                 * If one of the upstream stations beaconed
                                 * and the link to the upstream neighbor is
                                 * lost we need to restart the stuck timer to
                                 * check the "stuck beacon" condition.
                                 */
                                start_rmt_timer1(smc,smc->s.rmt_t_stuck,
                                        RM_TIMEOUT_T_STUCK) ;
                        }
                        /*
                         * We do NOT need to clear smc->r.bn_flag in case of
                         * not being in state T4 or T5, because the flag
                         * must be cleared in order to get in this condition.
                         */

                        DB_RMTN(2, "RMT : sm_mac_get_tx_state() = %d (bn_flag = %d)",
                                tx, smc->r.bn_flag);
                }
                /*RM34a*/
                else if (cmd == RM_MY_CLAIM && smc->r.timer0_exp) {
                        rmt_new_dup_actions(smc) ;
                        GO_STATE(RM4_NON_OP_DUP) ;
                        break ;
                }
                /*RM34b*/
                else if (cmd == RM_MY_BEACON && smc->r.timer0_exp) {
                        rmt_new_dup_actions(smc) ;
                        GO_STATE(RM4_NON_OP_DUP) ;
                        break ;
                }
                /*RM34c*/
                else if (cmd == RM_VALID_CLAIM) {
                        rmt_new_dup_actions(smc) ;
                        GO_STATE(RM4_NON_OP_DUP) ;
                        break ;
                }
                /*RM36*/
                else if (cmd == RM_TIMEOUT_T_STUCK &&
                        smc->r.rm_join && smc->r.bn_flag) {
                        GO_STATE(RM6_DIRECTED) ;
                        break ;
                }
                break ;
        case ACTIONS(RM4_NON_OP_DUP) :
                start_rmt_timer0(smc,smc->s.rmt_t_announce,RM_TIMEOUT_ANNOUNCE);
                start_rmt_timer1(smc,smc->s.rmt_t_stuck,RM_TIMEOUT_T_STUCK) ;
                start_rmt_timer2(smc,smc->s.rmt_t_poll,RM_TIMEOUT_POLL) ;
                sm_mac_check_beacon_claim(smc) ;
                DB_RMTN(1, "RMT : RM4_NON_OP_DUP");
                ACTIONS_DONE() ;
                break ;
        case RM4_NON_OP_DUP :
                if (cmd == RM_TIMEOUT_POLL) {
                        start_rmt_timer2(smc,smc->s.rmt_t_poll,RM_TIMEOUT_POLL);
                        sm_mac_check_beacon_claim(smc) ;
                        break ;
                }
                /*RM41*/
                if (!smc->r.da_flag) {
                        GO_STATE(RM1_NON_OP) ;
                        break ;
                }
                /*RM44a*/
                else if ((cmd == RM_MY_BEACON || cmd == RM_OTHER_BEACON) &&
                        smc->r.bn_flag) {
                        smc->r.bn_flag = FALSE ;
                }
                /*RM44b*/
                else if (cmd == RM_TRT_EXP && !smc->r.bn_flag) {
                        int     tx ;
                        /*
                         * set bn_flag only if in state T4 or T5:
                         * only if we're the beaconer should we start the
                         * trace !
                         */
                        if ((tx =  sm_mac_get_tx_state(smc)) == 4 || tx == 5) {
                        DB_RMTN(2, "RMT : NOPDUP && TRT_EXPIRED && T4/T5");
                                smc->r.bn_flag = TRUE ;
                                /*
                                 * If one of the upstream stations beaconed
                                 * and the link to the upstream neighbor is
                                 * lost we need to restart the stuck timer to
                                 * check the "stuck beacon" condition.
                                 */
                                start_rmt_timer1(smc,smc->s.rmt_t_stuck,
                                        RM_TIMEOUT_T_STUCK) ;
                        }
                        /*
                         * We do NOT need to clear smc->r.bn_flag in case of
                         * not being in state T4 or T5, because the flag
                         * must be cleared in order to get in this condition.
                         */

                        DB_RMTN(2, "RMT : sm_mac_get_tx_state() = %d (bn_flag = %d)",
                                tx, smc->r.bn_flag);
                }
                /*RM44c*/
                else if (cmd == RM_TIMEOUT_ANNOUNCE && !smc->r.bn_flag) {
                        rmt_dup_actions(smc) ;
                }
                /*RM45*/
                else if (cmd == RM_RING_OP) {
                        smc->r.no_flag = FALSE ;
                        GO_STATE(RM5_RING_OP_DUP) ;
                        break ;
                }
                /*RM46*/
                else if (cmd == RM_TIMEOUT_T_STUCK &&
                        smc->r.rm_join && smc->r.bn_flag) {
                        GO_STATE(RM6_DIRECTED) ;
                        break ;
                }
                break ;
        case ACTIONS(RM5_RING_OP_DUP) :
                stop_rmt_timer0(smc) ;
                stop_rmt_timer1(smc) ;
                stop_rmt_timer2(smc) ;
                DB_RMTN(1, "RMT : RM5_RING_OP_DUP");
                ACTIONS_DONE() ;
                break;
        case RM5_RING_OP_DUP :
                /*RM52*/
                if (smc->r.dup_addr_test == DA_PASSED) {
                        smc->r.da_flag = FALSE ;
                        GO_STATE(RM2_RING_OP) ;
                        break ;
                }
                /*RM54*/
                else if (cmd == RM_RING_NON_OP) {
                        smc->r.jm_flag = FALSE ;
                        smc->r.bn_flag = FALSE ;
                        GO_STATE(RM4_NON_OP_DUP) ;
                        break ;
                }
                break ;
        case ACTIONS(RM6_DIRECTED) :
                start_rmt_timer0(smc,smc->s.rmt_t_direct,RM_TIMEOUT_T_DIRECT) ;
                stop_rmt_timer1(smc) ;
                start_rmt_timer2(smc,smc->s.rmt_t_poll,RM_TIMEOUT_POLL) ;
                sm_ma_control(smc,MA_DIRECTED) ;
                RS_SET(smc,RS_BEACON) ;
                DB_RMTN(1, "RMT : RM6_DIRECTED");
                ACTIONS_DONE() ;
                break ;
        case RM6_DIRECTED :
                /*RM63*/
                if (cmd == RM_TIMEOUT_POLL) {
                        start_rmt_timer2(smc,smc->s.rmt_t_poll,RM_TIMEOUT_POLL);
                        sm_mac_check_beacon_claim(smc) ;
#ifndef SUPERNET_3
                        /* Because of problems with the Supernet II chip set
                         * sending of Directed Beacon will stop after 165ms
                         * therefore restart_trt_for_dbcn(smc) will be called
                         * to prevent this.
                         */
                        restart_trt_for_dbcn(smc) ;
#endif /*SUPERNET_3*/
                        break ;
                }
                if ((cmd == RM_MY_BEACON || cmd == RM_OTHER_BEACON) &&
                        !smc->r.da_flag) {
                        smc->r.bn_flag = FALSE ;
                        GO_STATE(RM3_DETECT) ;
                        break ;
                }
                /*RM64*/
                else if ((cmd == RM_MY_BEACON || cmd == RM_OTHER_BEACON) &&
                        smc->r.da_flag) {
                        smc->r.bn_flag = FALSE ;
                        GO_STATE(RM4_NON_OP_DUP) ;
                        break ;
                }
                /*RM67*/
                else if (cmd == RM_TIMEOUT_T_DIRECT) {
                        GO_STATE(RM7_TRACE) ;
                        break ;
                }
                break ;
        case ACTIONS(RM7_TRACE) :
                stop_rmt_timer0(smc) ;
                stop_rmt_timer1(smc) ;
                stop_rmt_timer2(smc) ;
                smc->e.trace_prop |= ENTITY_BIT(ENTITY_MAC) ;
                queue_event(smc,EVENT_ECM,EC_TRACE_PROP) ;
                DB_RMTN(1, "RMT : RM7_TRACE");
                ACTIONS_DONE() ;
                break ;
        case RM7_TRACE :
                break ;
        default:
                SMT_PANIC(smc,SMT_E0122, SMT_E0122_MSG) ;
                break;
        }
}

/*
 * (jd) RMT duplicate address actions
 * leave the ring or reinsert just as configured
 */
static void rmt_dup_actions(struct s_smc *smc)
{
        if (smc->r.jm_flag) {
        }
        else {
                if (smc->s.rmt_dup_mac_behavior) {
                        SMT_ERR_LOG(smc,SMT_E0138, SMT_E0138_MSG) ;
                        rmt_reinsert_actions(smc) ;
                }
                else {
                        SMT_ERR_LOG(smc,SMT_E0135, SMT_E0135_MSG) ;
                        rmt_leave_actions(smc) ;
                }
        }
}

/*
 * Reconnect to the Ring
 */
static void rmt_reinsert_actions(struct s_smc *smc)
{
        queue_event(smc,EVENT_ECM,EC_DISCONNECT) ;
        queue_event(smc,EVENT_ECM,EC_CONNECT) ;
}

/*
 * duplicate address detected
 */
static void rmt_new_dup_actions(struct s_smc *smc)
{
        smc->r.da_flag = TRUE ;
        smc->r.bn_flag = FALSE ;
        smc->r.jm_flag = FALSE ;
        /*
         * we have three options : change address, jam or leave
         * we leave the ring as default 
         * Optionally it's possible to reinsert after leaving the Ring
         * but this will not conform with SMT Spec.
         */
        if (smc->s.rmt_dup_mac_behavior) {
                SMT_ERR_LOG(smc,SMT_E0138, SMT_E0138_MSG) ;
                rmt_reinsert_actions(smc) ;
        }
        else {
                SMT_ERR_LOG(smc,SMT_E0135, SMT_E0135_MSG) ;
                rmt_leave_actions(smc) ;
        }
}


/*
 * leave the ring
 */
static void rmt_leave_actions(struct s_smc *smc)
{
        queue_event(smc,EVENT_ECM,EC_DISCONNECT) ;
        /*
         * Note: Do NOT try again later. (with please reconnect)
         * The station must be left from the ring!
         */
}

/*
 * SMT timer interface
 *      start RMT timer 0
 */
static void start_rmt_timer0(struct s_smc *smc, u_long value, int event)
{
        smc->r.timer0_exp = FALSE ;             /* clear timer event flag */
        smt_timer_start(smc,&smc->r.rmt_timer0,value,EV_TOKEN(EVENT_RMT,event));
}

/*
 * SMT timer interface
 *      start RMT timer 1
 */
static void start_rmt_timer1(struct s_smc *smc, u_long value, int event)
{
        smc->r.timer1_exp = FALSE ;     /* clear timer event flag */
        smt_timer_start(smc,&smc->r.rmt_timer1,value,EV_TOKEN(EVENT_RMT,event));
}

/*
 * SMT timer interface
 *      start RMT timer 2
 */
static void start_rmt_timer2(struct s_smc *smc, u_long value, int event)
{
        smc->r.timer2_exp = FALSE ;             /* clear timer event flag */
        smt_timer_start(smc,&smc->r.rmt_timer2,value,EV_TOKEN(EVENT_RMT,event));
}

/*
 * SMT timer interface
 *      stop RMT timer 0
 */
static void stop_rmt_timer0(struct s_smc *smc)
{
        if (smc->r.rmt_timer0.tm_active)
                smt_timer_stop(smc,&smc->r.rmt_timer0) ;
}

/*
 * SMT timer interface
 *      stop RMT timer 1
 */
static void stop_rmt_timer1(struct s_smc *smc)
{
        if (smc->r.rmt_timer1.tm_active)
                smt_timer_stop(smc,&smc->r.rmt_timer1) ;
}

/*
 * SMT timer interface
 *      stop RMT timer 2
 */
static void stop_rmt_timer2(struct s_smc *smc)
{
        if (smc->r.rmt_timer2.tm_active)
                smt_timer_stop(smc,&smc->r.rmt_timer2) ;
}