/*******************************************************************************
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#   Copyright (c) [2017-2019] [Radisys]                                        #
#                                                                              #
#   Licensed under the Apache License, Version 2.0 (the "License");            #
#   you may not use this file except in compliance with the License.           #
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#       http://www.apache.org/licenses/LICENSE-2.0                             #
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*******************************************************************************/

/************************************************************************
 
     Name:     sch_rach.c
  
     Type:     C source file
  
     Desc:     C source code for rach handling functions
  
     File:     sch_rach.c
  
**********************************************************************/

/** @file sch_rach.c
@brief This file implements the rach handling.
*/
#include "common_def.h"
#include "tfu.h"
#include "lrg.h"
#include "tfu.x"
#include "lrg.x"
#include "du_log.h"
#include "du_app_mac_inf.h"
#include "mac_sch_interface.h"
#include "sch.h"
#include "sch_utils.h"

SchCb schCb[SCH_MAX_INST];
uint8_t puschDeltaTable[MAX_MU_PUSCH];

/**
 * @brief calculate ra-rnti function. 
 *
 * @details
 *
 *     Function : calculateRaRnti
 *     
 *     This function calculates ra-rnti
 *     
 *  @param[in]  symbol index
 *  @param[in]  slot index
 *  @param[in]  frequency index
 *  @return  ra-rnti
 **/
uint16_t calculateRaRnti(uint8_t symbolIdx, uint8_t slotIdx, uint8_t freqIdx)
{
   uint16_t raRnti = 0;
   uint8_t  ulCarrierIdx = 0; /* Uplink carrier used for MSG1 transmission. 0:NUL carrier; 1:SUL carrier */
   
   /* Refer to spec 38.321, section 5.1.3 */
   raRnti = (1 + symbolIdx + (14*slotIdx) + (14*80*freqIdx) + (14*80*8*ulCarrierIdx));
   return raRnti;
}

/**
 * @brief create raCb function. 
 *
 * @details
 *
 *     Function : createSchRaCb
 *     
 *     This function create raCb
 *     
 *  @param[in]  tcrnti
 *  @param[in]  shed instance
 *  @return  void
 **/
void createSchRaCb(uint16_t tcrnti, Inst schInst)
{
   uint8_t ueIdx = 0;

   GET_UE_IDX(tcrnti, ueIdx);
   schCb[schInst].cells[schInst]->raCb[ueIdx -1].tcrnti = tcrnti;
}

/**
 * @brief resource allocation for msg3 PUSCH
 *
 * @details
 *
 *     Function : schAllocMsg3Pusch 
 *     
 *     This function handles msg3 PUSCH allocation
 *     
 *  @param[in]  Inst schInst, SCH instance
 *  @param[in]  slot, current slot
 *  @param[out]  msg3StartRb
 *  @param[out]  msg3NumRb
 *  @return  void
 **/
SchPuschInfo* schAllocMsg3Pusch(Inst schInst, uint16_t slot, uint16_t crnti, uint16_t msg3SlotAlloc)
{
   SchCellCb      *cell          = NULLP;
   SchUlSlotInfo  *schUlSlotInfo = NULLP;
   uint8_t    startSymb     = 0;
   uint8_t    symbLen       = 0; 
   uint8_t    startRb       = 0;
   uint8_t    numRb         = 0;
   uint8_t    idx           = 0;
   uint8_t    mcs            = 4;
   uint8_t    numPdschSymbols= 14;
   uint16_t   tbSize         = 0;

   cell = schCb[schInst].cells[schInst];
   startSymb = cell->cellCfg.schInitialUlBwp.puschCommon.timeDomRsrcAllocList[0].startSymbol;
   symbLen = cell->cellCfg.schInitialUlBwp.puschCommon.timeDomRsrcAllocList[0].symbolLength;

   startRb = cell->schUlSlotInfo[msg3SlotAlloc]->puschCurrentPrb;
   tbSize = schCalcTbSize(8); /* 6 bytes msg3  and 2 bytes header */
   numRb = schCalcNumPrb(tbSize, mcs, numPdschSymbols);

   /* allocating 1 extra RB for now */
   numRb++;
   /* increment PUSCH PRB */
   cell->schUlSlotInfo[msg3SlotAlloc]->puschCurrentPrb += numRb;

   for(idx=startSymb; idx<symbLen; idx++)
   {
      cell->schUlSlotInfo[msg3SlotAlloc]->assignedPrb[idx] = startRb + numRb;
   }
   schUlSlotInfo = cell->schUlSlotInfo[msg3SlotAlloc];

   SCH_ALLOC(schUlSlotInfo->schPuschInfo, sizeof(SchPuschInfo));
   if(!schUlSlotInfo->schPuschInfo)
   {
      DU_LOG("\nERROR  -->  SCH :  Memory allocation failed in schAllocMsg3Pusch");
      return NULLP;
   }
   tbSize = 0;  /* since nPrb has been incremented, recalculating tbSize */
   tbSize = schCalcTbSizeFromNPrb(numRb, mcs, numPdschSymbols);
   tbSize = tbSize/8;/*bits to byte conversion*/
   schUlSlotInfo->schPuschInfo->crnti             = crnti;
   schUlSlotInfo->schPuschInfo->harqProcId        = SCH_HARQ_PROC_ID;
   schUlSlotInfo->schPuschInfo->resAllocType      = SCH_ALLOC_TYPE_1;
   schUlSlotInfo->schPuschInfo->fdAlloc.startPrb  = startRb;
   schUlSlotInfo->schPuschInfo->fdAlloc.numPrb    = numRb;
   schUlSlotInfo->schPuschInfo->tdAlloc.startSymb = startSymb;
   schUlSlotInfo->schPuschInfo->tdAlloc.numSymb   = symbLen;
   schUlSlotInfo->schPuschInfo->tbInfo.qamOrder   = 2;  /* QPSK modulation */
   schUlSlotInfo->schPuschInfo->tbInfo.mcs	  = mcs;
   schUlSlotInfo->schPuschInfo->tbInfo.mcsTable   = SCH_MCS_TABLE_QAM_64;
   schUlSlotInfo->schPuschInfo->tbInfo.ndi        = 1; /* new transmission */
   schUlSlotInfo->schPuschInfo->tbInfo.rv	  = 0;
   schUlSlotInfo->schPuschInfo->tbInfo.tbSize     = tbSize; /*Considering 2 PRBs */
   schUlSlotInfo->schPuschInfo->dmrsMappingType   = DMRS_MAP_TYPE_A;  /* Setting Type-A */
   schUlSlotInfo->schPuschInfo->nrOfDmrsSymbols   = NUM_DMRS_SYMBOLS;
   schUlSlotInfo->schPuschInfo->dmrsAddPos        = DMRS_ADDITIONAL_POS;

   return schUlSlotInfo->schPuschInfo;
}

/**
 * @brief Processes any pending RA request
 *
 * @details
 *
 *     Function : schProcessRaReq
 *
 *     This function process pending RA request
 *
 *  @param[in]  Current timing of the cell
 *  @return  ROK
 **/
void schProcessRaReq(SlotTimingInfo currTime, SchCellCb *cell)
{
   uint8_t ueIdx = 0;
   SchPuschInfo *msg3PuschInfo;
   RarInfo *rarInfo = NULLP;
   uint8_t delta = 0;
   uint8_t k2Index = 0, k2 = 0;
   uint8_t puschMu = 0;
   uint16_t rarSlot = 0;
   uint16_t msg3Slot = 0;
#ifdef NR_TDD
   uint16_t slotIdx = 0;
#endif

   while(ueIdx < MAX_NUM_UE)
   {
      if(cell->raReq[ueIdx] == NULLP)
      {
         ueIdx++;
         continue;
      }

      //puschMu = cell->cellCfg.puschMu;
      delta = puschDeltaTable[puschMu];
      k2 = cell->cellCfg.schInitialUlBwp.puschCommon.timeDomRsrcAllocList[k2Index].k2;

      /* RAR will sent with a delay of RAR_DELAY */
      rarSlot = (currTime.slot + RAR_DELAY + PHY_DELTA_DL) % cell->numSlots;
#ifdef NR_TDD
      for(slotIdx=0; slotIdx<cell->numSlots;slotIdx++)
      {
         /* Slot allocation for msg3 based on 38.214 section 6.1.2.1 */
         msg3Slot = (rarSlot+delta+k2)%cell->numSlots;

         if((schGetSlotSymbFrmt(rarSlot, cell->slotFrmtBitMap) != DL_SLOT) &&\
               (schGetSlotSymbFrmt(msg3Slot, cell->slotFrmtBitMap) != UL_SLOT))
         {
            rarSlot = (rarSlot + 1) % cell->numSlots;
            continue;
         }
         break;
      }
      if(slotIdx>=cell->numSlots)
      {
         DU_LOG("\nERROR  -->  SCH : NO Slot for Msg2 with Msg3 Grant\n");
         return RFAILED;
      }
#else
      /* Slot allocation for msg3 based on 38.214 section 6.1.2.1 */
      msg3Slot = rarSlot + k2 + delta;
      msg3Slot = msg3Slot % cell->numSlots; 
#endif

      SchDlSlotInfo *schDlSlotInfo = cell->schDlSlotInfo[rarSlot]; /* RAR will sent in the next slot */

      /* Allocate the rarInfo, this pointer will be checked at schProcessSlotInd function */
      SCH_ALLOC(rarInfo, sizeof(RarInfo));
      if(rarInfo == NULLP)
      {
         DU_LOG("\nERROR  -->  SCH : Memory Allocation failed for rarInfo");
         return RFAILED;
      }

      schDlSlotInfo->rarInfo = rarInfo;

      /* create raCb at SCH */
      createSchRaCb(cell->raReq[ueIdx]->rachInd->crnti, cell->instIdx);

      /* allocate resources for msg3 */
      msg3PuschInfo = schAllocMsg3Pusch(cell->instIdx, rarSlot, cell->raReq[ueIdx]->rachInd->crnti, msg3Slot);
      if(msg3PuschInfo)
      {
         /* fill RAR info */
         rarInfo->raRnti = cell->raReq[ueIdx]->raRnti;
         rarInfo->tcrnti = cell->raReq[ueIdx]->rachInd->crnti;
         rarInfo->RAPID = cell->raReq[ueIdx]->rachInd->preambleIdx;
         rarInfo->ta = cell->raReq[ueIdx]->rachInd->timingAdv;
         rarInfo->ulGrant.bwpSize = cell->cellCfg.schInitialUlBwp.bwp.freqAlloc.numPrb;
         /* Spec 38.213, section 8.2, 0 : MSG3 PUSCH will be transmitted without frequency hopping */
         rarInfo->ulGrant.freqHopFlag = 0;
         rarInfo->ulGrant.msg3FreqAlloc.startPrb = msg3PuschInfo->fdAlloc.startPrb;
         rarInfo->ulGrant.msg3FreqAlloc.numPrb = msg3PuschInfo->fdAlloc.numPrb;
         rarInfo->ulGrant.k2Index = k2Index;
         rarInfo->ulGrant.mcs = msg3PuschInfo->tbInfo.mcs;
         rarInfo->ulGrant.tpc = 3;  /* TODO : Check appropriate value to be filled */
         /* Spec 38.213, section 8.2 : In a contention based random access
          * procedure, the CSI request field is reserved. */
         rarInfo->ulGrant.csiReq = 0;
      }

      SCH_FREE(cell->raReq[ueIdx]->rachInd, sizeof(RachIndInfo));
      SCH_FREE(cell->raReq[ueIdx], sizeof(SchRaReq));
      ueIdx++;

   } /* End of while(ueIdx < MAX_NUM_UE) */
}

/**
 * @brief process rach indication function. 
 *
 * @details
 *
 *     Function : schProcessRachInd
 *     
 *     This function process rach indication
 *     
 *  @param[in]  rachInd parameters
 *  @param[in]  shed instance
 *  @return  ROK
 **/
uint8_t schProcessRachInd(RachIndInfo *rachInd, Inst schInst)
{
   SchCellCb *cell = schCb[schInst].cells[schInst];
   SchRaReq  *raReq = NULLP;
   float    slotDuration;
   uint8_t  winNumSlots;
   uint8_t  ueIdx;

   SCH_ALLOC(raReq, sizeof(SchRaReq));
   if(!raReq)
   {
      DU_LOG("\nERROR  -->  SCH : Memory allocation failure in schProcessRachInd");
      SCH_FREE(rachInd, sizeof(RachIndInfo));
      return RFAILED;
   }

   /* calculate the ra-rnti value */
   raReq->raRnti = calculateRaRnti(rachInd->symbolIdx, rachInd->slotIdx, rachInd->freqIdx);
   raReq->rachInd = rachInd;
   raReq->winStartTime.sfn = rachInd->timingInfo.sfn;
   raReq->winStartTime.slot = rachInd->timingInfo.slot;
  
   /* Converting window size from ms to number of slots */
   slotDuration = (1 / pow(2, cell->cellCfg.numerology));
   winNumSlots = (float)cell->cellCfg.schRachCfg.raRspWindow / slotDuration;
   
   /* Adding window size to window start time to get window end time */
   ADD_DELTA_TO_TIME(raReq->winStartTime, raReq->winEndTime, winNumSlots);

   /* Storing RA request in cellCb */
   GET_UE_IDX(rachInd->crnti, ueIdx);
   cell->raReq[ueIdx] = raReq;

   return ROK;
}

/**
 * @brief fill RAR info function. 
 *
 * @details
 *
 *     Function : calculateRaRnti
 *     
 *     This function fills pdcch and pdsch info for RAR
 *     
 *  @param[in]  rar Allocation info
 *  @param[in]  ra-rnti
 *  @param[in]  PCI
 *  @param[in]  offset to pointA to determine freq alloc
 *  @return  ROK
 **/
uint8_t schFillRar(RarAlloc *rarAlloc, uint16_t raRnti, uint16_t pci, uint8_t offsetPointA, \
bool ssbPresent, bool sib1Present)
{
   Inst inst = 0;
   uint8_t coreset0Idx = 0;
   uint8_t numRbs = 0;
   uint8_t firstSymbol = 0;
   uint8_t numSymbols = 0;
   uint8_t offset = 0;
   uint8_t FreqDomainResource[6] = {0};
   uint16_t tbSize = 0;
   uint8_t mcs = 4;  /* MCS fixed to 4 */

   SchBwpDlCfg *initialBwp = &schCb[inst].cells[inst]->cellCfg.schInitialDlBwp;
   PdcchCfg *pdcch = &rarAlloc->rarPdcchCfg;
   PdschCfg *pdsch = &rarAlloc->rarPdschCfg;
   BwpCfg *bwp = &rarAlloc->bwp;
   FreqDomainAlloc *sib1PdschFreqAlloc = NULL;

   coreset0Idx     = initialBwp->pdcchCommon.commonSearchSpace.coresetId;

   /* derive the sib1 coreset0 params from table 13-1 spec 38.213 */
   numRbs        = coresetIdxTable[coreset0Idx][1];
   numSymbols    = coresetIdxTable[coreset0Idx][2];
   offset        = coresetIdxTable[coreset0Idx][3];

   /* calculate time domain parameters */
   // note: since slot value is made sl1, RAR can be sent at all slots
   uint16_t mask = 0x2000;
   for(firstSymbol=0; firstSymbol<14;firstSymbol++)
   {
      if(initialBwp->pdcchCommon.commonSearchSpace.monitoringSymbol & mask)
	 break;
      else
	 mask = mask>>1;
   }

   /* calculate the PRBs */
   freqDomRscAllocType0(((offsetPointA-offset)/6), (numRbs/6), FreqDomainResource);

   /* fill BWP */
   bwp->freqAlloc.numPrb   = initialBwp->bwp.freqAlloc.numPrb;
   bwp->freqAlloc.startPrb = initialBwp->bwp.freqAlloc.startPrb;
   bwp->subcarrierSpacing  = initialBwp->bwp.scs;
   bwp->cyclicPrefix       = initialBwp->bwp.cyclicPrefix;

   /* fill the PDCCH PDU */
   pdcch->coresetCfg.startSymbolIndex = firstSymbol;
   pdcch->coresetCfg.durationSymbols = numSymbols;
   memcpy(pdcch->coresetCfg.freqDomainResource, FreqDomainResource, FREQ_DOM_RSRC_SIZE);
   pdcch->coresetCfg.cceRegMappingType = 1; /* coreset0 is always interleaved */
   pdcch->coresetCfg.regBundleSize = 6;    /* spec-38.211 sec 7.3.2.2 */
   pdcch->coresetCfg.interleaverSize = 2;  /* spec-38.211 sec 7.3.2.2 */
   pdcch->coresetCfg.coreSetType = 0;
   pdcch->coresetCfg.shiftIndex = pci;
   pdcch->coresetCfg.precoderGranularity = 0; /* sameAsRegBundle */
   pdcch->numDlDci = 1;
   pdcch->dci.rnti = raRnti; /* RA-RNTI */
   pdcch->dci.scramblingId = pci;
   pdcch->dci.scramblingRnti = 0;
   pdcch->dci.cceIndex = 4; /* considering SIB1 is sent at cce 0-1-2-3 */
   pdcch->dci.aggregLevel = 4;
   pdcch->dci.beamPdcchInfo.numPrgs = 1;
   pdcch->dci.beamPdcchInfo.prgSize = 1;
   pdcch->dci.beamPdcchInfo.digBfInterfaces = 0;
   pdcch->dci.beamPdcchInfo.prg[0].pmIdx = 0;
   pdcch->dci.beamPdcchInfo.prg[0].beamIdx[0] = 0;
   pdcch->dci.txPdcchPower.powerValue = 0;
   pdcch->dci.txPdcchPower.powerControlOffsetSS = 0;
   pdcch->dci.pdschCfg = pdsch;

   /* fill the PDSCH PDU */
   uint8_t cwCount = 0;
   pdsch->pduBitmap = 0; /* PTRS and CBG params are excluded */
   pdsch->rnti = raRnti; /* RA-RNTI */
   pdsch->pduIndex = 0;
   pdsch->numCodewords = 1;
   for(cwCount = 0; cwCount < pdsch->numCodewords; cwCount++)
   {
      pdsch->codeword[cwCount].targetCodeRate = 308;
      pdsch->codeword[cwCount].qamModOrder = 2;
      pdsch->codeword[cwCount].mcsIndex = mcs; /* mcs configured to 4 */
      pdsch->codeword[cwCount].mcsTable = 0;   /* notqam256 */
      pdsch->codeword[cwCount].rvIndex = 0;
      /* RAR PDU length and FAPI payload header length */
      tbSize = schCalcTbSize(RAR_PAYLOAD_SIZE + TX_PAYLOAD_HDR_LEN);
      pdsch->codeword[cwCount].tbSize = tbSize;
   }
   pdsch->dataScramblingId = pci;
   pdsch->numLayers = 1;
   pdsch->transmissionScheme = 0;
   pdsch->refPoint = 0;
   pdsch->dmrs.dlDmrsSymbPos = 4;  /* Bitmap value 00000000000100 i.e. using 3rd symbol for PDSCH DMRS */
   pdsch->dmrs.dmrsConfigType = 0; /* type-1 */
   pdsch->dmrs.dlDmrsScramblingId = pci;
   pdsch->dmrs.scid = 0;
   pdsch->dmrs.numDmrsCdmGrpsNoData = 1;
   pdsch->dmrs.dmrsPorts = 0;
   pdsch->dmrs.mappingType      = DMRS_MAP_TYPE_A;  /* Type-A */
   pdsch->dmrs.nrOfDmrsSymbols  = NUM_DMRS_SYMBOLS;
   pdsch->dmrs.dmrsAddPos       = DMRS_ADDITIONAL_POS;
   pdsch->pdschFreqAlloc.resourceAllocType = 1; /* RAT type-1 RIV format */
   /* The RB numbering starts from coreset0 */ 
   pdsch->pdschFreqAlloc.freqAlloc.startPrb = PDSCH_START_RB;
   if(ssbPresent)
   {
      /* PDSCH is always above SSB */
      pdsch->pdschFreqAlloc.freqAlloc.startPrb = offsetPointA + SCH_SSB_NUM_PRB + 1;
   }
   if(sib1Present)
   {
      /* Must not overlap with SIB1 */
      sib1PdschFreqAlloc = &schCb[inst].cells[inst]->cellCfg.sib1SchCfg.sib1PdschCfg.pdschFreqAlloc.freqAlloc;
      pdsch->pdschFreqAlloc.freqAlloc.startPrb = sib1PdschFreqAlloc->startPrb + sib1PdschFreqAlloc->numPrb + 1; 
   }
   pdsch->pdschFreqAlloc.freqAlloc.numPrb = schCalcNumPrb(tbSize, mcs, \
      initialBwp->pdschCommon.timeDomRsrcAllocList[0].lengthSymbol);
   pdsch->pdschFreqAlloc.vrbPrbMapping = 0; /* non-interleaved */
   pdsch->pdschTimeAlloc.timeAlloc.startSymb = initialBwp->pdschCommon.timeDomRsrcAllocList[0].startSymbol;
   pdsch->pdschTimeAlloc.timeAlloc.numSymb = initialBwp->pdschCommon.timeDomRsrcAllocList[0].lengthSymbol;
   pdsch->beamPdschInfo.numPrgs = 1;
   pdsch->beamPdschInfo.prgSize = 1;
   pdsch->beamPdschInfo.digBfInterfaces = 0;
   pdsch->beamPdschInfo.prg[0].pmIdx = 0;
   pdsch->beamPdschInfo.prg[0].beamIdx[0] = 0;
   pdsch->txPdschPower.powerControlOffset = 0;
   pdsch->txPdschPower.powerControlOffsetSS = 0;

   return ROK;
}

/**********************************************************************
         End of file
**********************************************************************/