// ========== Copyright Header Begin ==========================================
// 
// OpenSPARC T2 Processor File: niu_rx_descp_sch.vr
// Copyright (C) 1995-2007 Sun Microsystems, Inc. All Rights Reserved
// 4150 Network Circle, Santa Clara, California 95054, U.S.A.
//
// * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 
//
// 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; version 2 of the License.
//
// 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
// 
// For the avoidance of doubt, and except that if any non-GPL license 
// choice is available it will apply instead, Sun elects to use only 
// the General Public License version 2 (GPLv2) at this time for any 
// software where a choice of GPL license versions is made 
// available with the language indicating that GPLv2 or any later version 
// may be used, or where a choice of which version of the GPL is applied is 
// otherwise unspecified. 
//
// Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 
// CA 95054 USA or visit www.sun.com if you need additional information or 
// have any questions. 
// 
// ========== Copyright Header End ============================================
#include <vera_defines.vrh>
#include <ListMacros.vrh>
#include "niu_mem.vrh"
#include "niu_rxtoken.vrh"
#include "niu_dmc_descr_ring.vrh"

extern CSparseMem SparseMem;

#define DESCR_DONE 1
#define DESCR_NOT_DONE 0

class CRxDescSch extends CRxdescriptor {

  // This is the place holder for the descriptor before scheduling one
  integer id;
  bit [63:0]address;// Address of this descriptor
  bit [63:0] virtaddress;// Address of this descriptor
  integer valid;
  integer blk_size;
  integer buf_size;
  integer bytes_allocated;
  integer index;


  task new( ( integer i =0)) {
    id = 0;
    valid = 0;
    bytes_allocated = 0;
    index = 0;
  }

  function bit[63:0] getAddress ( integer length, var bit[63:0] vaddr ) {
    getAddress = address + bytes_allocated;
    vaddr = virtaddress + bytes_allocated;
    bytes_allocated = bytes_allocated + buf_size;
    printf(" RDMC DEBUG - buf_size- %d bytes_allocated - %d Address - %x\n",buf_size,bytes_allocated,getAddress);
    if(bytes_allocated >blk_size) {
     printf(" ERROR Potential Programming error or Testbench ERROR -- \n");
    }
  }

  function integer checkState () {
    if(bytes_allocated == blk_size) {
      checkState = DESCR_DONE;
      printf(" RDMC DEBUG - DONE WITH THIS DESCRIPTOR \n");
    } else { checkState = DESCR_NOT_DONE;
    }
  }
}


MakeVeraList(CRxDescSch) // list of descriptors

class CRxDescrSchRing extends CDescrRing {

    VeraList_CRxDescSch desc_ring;
    integer index;
    task new(integer i = 0) {
	   id = i;
	   index =0;
           desc_ring = new();
        }
	function CRxDescSch front() {
	  front = desc_ring.front();
        }
   	task pop_front(){
      	  desc_ring.pop_front();
   	}
        task push_back( CRxDescSch desc ) {
	  desc.index = index++;
	  desc_ring.push_back(desc);
	  //printf(" in CRxDescSch: Size - - %d \n",desc_ring.size());
       }
	function CRxDescSch back() { 
	  back = desc_ring.back();
	  printf(" in CRxDescSch: address - %x \n",back.blk_addr);
        }
	function integer get_ring_size() {
            get_ring_size = desc_ring.size();
	}

// Something fishy here---
        function integer isRingEmpty() {
         if(get_ring_size()) isRingEmpty = 0;
         else isRingEmpty = 1;
       }
}

class CRxdescpScheduler {

  integer valid;
  integer id;
  // Variables needed for carving logic to work
  bit vld0,vld1,vld2;
  integer blk_size;
  integer bufsz0,bufsz1,bufsz2;

  CRxDescrSchRing desc_ring;

  CRxDescSch RxDescSchSMALL;
  CRxDescSch RxDescSchMEDIUM;
  CRxDescSch RxDescSchLARGE;
  static bit [2:0]  RxDescState[32]; // indicates which ones are popped out and are valid
  integer reclaim_index;
  integer last_reclaim_index;

  

  task new(integer i) {
   id = i;
    vld0 = 0;
    vld1 = 0;
    vld2 = 0;
    reclaim_index = 0;
    last_reclaim_index = 0;
    desc_ring = new();
    RxDescState[i] = 0;
    // printf(" CRxdescpScheduler- Newd\n");
  }

  task set_blk_size(bit [1:0] s) ;
  task set_bufsz0(bit [1:0] s,integer v) ;
  task set_bufsz1(bit [1:0] s,integer v) ;
  task set_bufsz2(bit [1:0] s,integer v) ;
  task print() {
   printf("CRxdescpScheduler DMA-%d  - bufsz0 - %d bufz1 - %d bufz2 - %d vld0 - %d vld1 - %d vld2 - %d \n",id,bufsz0,bufsz1,bufsz2, vld0,vld1,vld2 );
  }



   function integer get_reclaim_index ( ) { get_reclaim_index = reclaim_index; }
   task pushDescForSch( bit [31:0] address, (integer pkt_page_id = 0) ) ; 
   local function integer getNextDesc( var CRxDescSch RxDescSch, var integer type);
   local function integer popDescrs();
   local task allocJumboPackets ( CRxToken RxToken, integer NoOfDescrNeeded );
   local task SetIndexForReclaim();
   function integer getAddress ( CRxToken RxToken );
   local task setDescType( CRxDescSch RxDescSch, integer type) {
     if(type == 2) {
       RxDescSchLARGE = new RxDescSch;
     } else if( type ==1) {
       RxDescSchMEDIUM = new RxDescSch;
     } else if( type ==0) {
       RxDescSchSMALL = new RxDescSch;
     } else {
       printf(" ERROR in setDescType \n");
     }
     
   }

}
task CRxdescpScheduler::set_blk_size(bit [1:0] s)  {
   case(s) {
    2'b00 :  blk_size = 4096;
    2'b01 :  blk_size = 8192;
    2'b10 :  blk_size = 16384;
    2'b11 :  blk_size = 32768;
 }
}
task CRxdescpScheduler::set_bufsz0(bit [1:0] s, integer v)  {
   bufsz0 = 256 * ( 1<<s ) ;
   vld0 = v;
}
task CRxdescpScheduler::set_bufsz1(bit [1:0] s, integer v)  {
   bufsz1 = 1024 * ( 1<<s ) ;
   vld1 = v;
}
task CRxdescpScheduler::set_bufsz2(bit [1:0] s, integer v)  {
   bufsz2 = 2048 * (1<< s) ;
   vld2 = v;
}

task CRxdescpScheduler::pushDescForSch( bit [31:0] address, (integer pkt_page_id = 0) ) {

   CRxDescSch RxDescSch;
   bit [39:0] xlate_address;
   bit [31:0] xlate_address_page;
   xlate_address = SparseMem.xlate_addr({address,12'h0},pkt_page_id);
   xlate_address_page = xlate_address[39:12];
   RxDescSch = new();
   // printf(" Pushing descriptor for DMA%d Descriptor - orig  %x xlate - %x \n",id,address,xlate_address[39:12]);

    case(blk_size) {
	4096 :  RxDescSch.address = {20'h0,xlate_address_page[31:0],12'h0};
	8192 :  RxDescSch.address = {20'h0,xlate_address_page[31:1],13'h0};
	16384 :  RxDescSch.address = {20'h0,xlate_address_page[31:2],14'h0};
	32768 :  RxDescSch.address = {20'h0,xlate_address_page[31:3],15'h0};
   }

    case(blk_size) {
	4096 :  RxDescSch.virtaddress = {20'h0,address[31:0],12'h0};
	8192 :  RxDescSch.virtaddress = {20'h0,address[31:1],13'h0};
	16384 :  RxDescSch.virtaddress = {20'h0,address[31:2],14'h0};
	32768 :  RxDescSch.virtaddress = {20'h0,address[31:3],15'h0};
   }
   // replace this with page handle

   desc_ring.push_back(RxDescSch);

}

task CRxdescpScheduler::SetIndexForReclaim() {

  // first check the state 
  // for each of the pop'd descriptor get the index
  // compute min of all of these and compare against the last accessed index
  
  integer index_small;
  integer index_medium;
  integer index_large;
  integer index_min;
  bit[2:0] State;
  // start with a large value
  index_small = 32'hffffff;
  index_medium = 32'hffffff;
  index_large = 32'hffffff;
  
  State = RxDescState[id];

  index_small = (State[0])? RxDescSchSMALL.index: index_small;
  index_medium = (State[1])? RxDescSchMEDIUM.index: index_medium;
  index_large = (State[2])? RxDescSchLARGE.index: index_large;

  // min value
   index_min = (index_small<index_medium) ? index_small: index_medium;
   index_min = (index_min<index_large) ? index_min : index_large;

   reclaim_index = (last_reclaim_index > index_min ) ? index_min : last_reclaim_index;

}



function integer CRxdescpScheduler::getNextDesc( var CRxDescSch RxDescSch, var integer type) {

  integer size;
  bit [2:0] State;

   size = desc_ring.get_ring_size();
   printf(" CRxdescpScheduler::getNextDesc: DMA- %d ring size - %d  isRingEmpty - %d \n",id,size,desc_ring.isRingEmpty()); 
   if(desc_ring.isRingEmpty() ) {
     getNextDesc = -1; // Ring is empty - packet to be dropped
     type = -1;
     return;

   } else {
    RxDescSch = desc_ring.front();
    printf(" CRxdescpScheduler::getNextDesc DMA- %d Address - %x  Index - %d\n", id,RxDescSch.address,RxDescSch.index);
    getNextDesc = size;
    desc_ring.pop_front();
   }

  // Mark this descriptor as either of S,M,L

  // check various enables -
  State = RxDescState[id];

  if(vld2 & ~State[2] ) {
    // Mark this as large
    RxDescSch.buf_size = bufsz2;
    RxDescSch.blk_size = blk_size;
    RxDescSch.valid = 1;
    State[2] = 1;
    type = 2;
  } else if(vld1 & ~State[1] ) {
    RxDescSch.buf_size = bufsz1;
    RxDescSch.blk_size = blk_size;
    RxDescSch.valid = 1;
    State[1] = 1;
    type = 1;
  } else if(vld0 & ~State[0] ) {
    RxDescSch.buf_size = bufsz0;
    RxDescSch.blk_size = blk_size;
    RxDescSch.valid = 1;
    State[0] = 1;
    type = 0;
  } else {
    printf(" ERROR--- MOST Likely testbench ERROR -- FIX IT \n");
    getNextDesc = -1;
  }

  RxDescState[id] = State;
  printf(" CRxdescpScheduler::getNextDesc DMA- %d  State - %b\n",id,State);

}

function integer CRxdescpScheduler::popDescrs() {

// This function always keeps various descriptors blocks available

  integer done;
  CRxDescSch RxDescSch;
  integer status,type;
  bit[2:0] State;
  State = RxDescState[id];

  if (vld2|vld1|vld0)
    done = (State == {vld2,vld1,vld0});
  else {
    popDescrs = -1;
    return;
  }
  printf( "CRxdescpScheduler::popDescrs DMA %d  State- %b Valid - %b\n",id,State,{vld2,vld1,vld0} );
  while(!done) {
  printf( "CRxdescpScheduler::popDescrs DMA %d State- %b  done - %d Valid - %b\n",id,State, done, {vld2,vld1,vld0});

   status = getNextDesc(RxDescSch,type);
    if(status == -1) {
      popDescrs = -1; // None available
      return;
     }
   setDescType( RxDescSch,type);
   State = RxDescState[id];
   if (vld2|vld1|vld0)
    done = (State == {vld2,vld1,vld0});
   else {
    popDescrs = -1;
    return;
   }
  printf( "CRxdescpScheduler::popDescrs DMA %d State- %b  done - %d  Valid - %b \n",id,State, done,{vld2,vld1,vld0} );
  }
  popDescrs = done;

}


task CRxdescpScheduler::allocJumboPackets ( CRxToken RxToken, integer NoOfDescrNeeded ) {

 integer i;
 CRxDescSch RxDescSch,RxDescSchUseForFirstBuf;
 integer bytes_remaining; 
 bit [63:0] packet_end_address;
 bit [63:0] address;
 bit [63:0] vaddr;

 
 bytes_remaining = RxToken.pkt_length + RxToken.header_length;


 for(i = 0; i < NoOfDescrNeeded; i ++ ) {
   RxDescSch = desc_ring.front();
   desc_ring.pop_front();
   address = RxDescSch.getAddress( blk_size, vaddr );
   RxToken.packet_start_address[i] = address;
   RxToken.packet_virtaddress[i] = vaddr;
   packet_end_address = (bytes_remaining>blk_size) ? (address + blk_size) : ( address + bytes_remaining);
   if (bytes_remaining >8) 
   packet_end_address = packet_end_address -8 ;
   RxToken.bytesperchunk[i] = (bytes_remaining>blk_size) ? blk_size : bytes_remaining;
   RxToken.packet_end_address[i] = {packet_end_address[63:3],3'h0}; 
   printf("CRxdescpScheduler::allocJumboPackets: RDMC DEBUG DMA - %d  - SCHEDULER ALLOC ADDRESS  - %x FOR JUMBO Scatter# - %d, PktType Set to %d Bytes- %d \n",id,RxToken.packet_start_address[i],i,RxToken.pkt_type,RxToken.bytesperchunk[i]);
 
   bytes_remaining = bytes_remaining - blk_size;
 }
 RxToken.NoOfScatter = NoOfDescrNeeded; 
 printf("CRxdescpScheduler::allocJumboPackets: RDMC DEBUG DMA - %d  - SCHEDULER ALLOC ADDRESS  - %x FOR JUMB NoOfDescrNeeded # - %d, PktType Set to %d Bytes- %d \n",id,RxToken.packet_start_address[NoOfDescrNeeded -1],NoOfDescrNeeded,RxToken.pkt_type,RxToken.bytesperchunk[NoOfDescrNeeded -1]);


}

function integer CRxdescpScheduler::getAddress ( CRxToken RxToken ) {





/*

   1. Check if enough descriptors are available- else get more descriptors
   2. Check the packet size and see which descriptor can be chosen ( among S, M, L )
   3. Once the descriptor is choosen, look at the bytes allocated to see space is available 
      else get more. Iterate untill this is done 



*/

 integer size;
 integer length;
 integer type;
 integer descp_state;
 integer status;
 CRxDescSch RxDescSch;
 bit [63:0] address,vaddr;
 integer offset;
 integer largest_available_pkt_buf;
 integer jumbo_packet;
 integer NoOfDescrNeeded;
 integer i;
 bit [2:0] State; 

 integer done;

 length = RxToken.pkt_length + RxToken.header_length;
 printf("RDMC DEBUG In Dma id - %d CRxdescpScheduler::getAddress Length - %d \n", RxToken.dma_num,length);
 printf( "RDMC DEBUG In Dma id - %d CRxdescpScheduler::getAddress  Current Descriptors poped out - %b \n",id,RxDescState[id]);
  

 done = 0;
 status = popDescrs();
 printf( "RDMC DEBUG  In Dma id - %d CRxdescpScheduler::getAddress Descriptors poped out  %b \n",id,RxDescState[id]);
 if(status == -1) {
   getAddress = -1; // None available -- packet to be dropped

   if(!(vld0|vld1|vld2)) {
     RxToken.pkt_type = VALID_DISABLED_DROP_RxPKT;
     printf("RDMC  DEBUG - Packet to be dropped - All 3 buf_size_valids are disabled\n");
   }
   else {
     RxToken.pkt_type = RNGFULL_DROP_RxPKT;
     printf("RDMC  DEBUG - Packet to be dropped - Either Ring is FULL or EMPTY- \n");
   }

   done = 1;
   return;
 }

 RxToken.pkt_type = GOOD_RxPKT;
 RxToken.bufsz = 3; 

 // determine if this packet is a jumbo packet


 largest_available_pkt_buf =  vld2 ? bufsz2 : (
                                     vld1 ? bufsz1: (
                                     vld0 ? bufsz0: 0) );
  

 if(length > largest_available_pkt_buf ) {
   jumbo_packet = 1;
 } else jumbo_packet = 0;

 // check  if this packet really qualifies as a jumbo packet ie 
 // how many buffer will this occupy

  if(!done & ( length > 3 * blk_size  )) {
   // this packet needs to be dropped
   // mark this packet bad and exit
   RxToken.pkt_type = BUFFSIZE_EXCEEDED_DROP_RxPKT;
   RxToken.jumbo_pkt = 1;
   done = 1;
   getAddress = 0; // None available
   return;
  } else {
  // this is the section to see  how the descriptors are to be used
  if(jumbo_packet) {
    // Find out how many descriptors are needed for this length. It has to be <= 3
    NoOfDescrNeeded = ( length/blk_size ) + ((length%blk_size) ? 1 :0);
    if(NoOfDescrNeeded == 0) {
     // should not happen --
     printf(" TESTBENCH ERROR -- FIX IT\n");
    }
    // Check if at least these many descriptors are available in the ring
    // if not drop the packet
     if(desc_ring.get_ring_size() >= NoOfDescrNeeded) {
       // Now split the packets and start writing into the memory 

       // Keep poping the descriptor and allocating into the address untill 
       // all the bytes are written
      

      allocJumboPackets( RxToken , NoOfDescrNeeded);

       // for(i=0;i<RxToken.NoOfScatter;i++) {
         // printf(" After allocJumboPackets- endaddress - %x i - %d\n",RxToken.packet_end_address[i],i);
       // }
      RxToken.pkt_type = GOOD_RxPKT;
      RxToken.jumbo_pkt = 1;
      getAddress = 1;
      done = 1;
      return;

     } else {
       // packet to be dropped !!!!
       RxToken.pkt_type = BUFFSIZE_EXCEEDED_DROP_RxPKT;
       RxToken.jumbo_pkt = 1;
       getAddress = 0; // None available
       done = 1;
       return;
     }
  }

}
 // for(i=0;i<RxToken.NoOfScatter;i++) {
         // printf(" in getaddress after allocJumboPackets- endaddress - %x i - %d\n",RxToken.packet_end_address[i],i);
       // }
  // Here the packet is not a jumbo packet and is within the limits of the pkt_buffer 
  // scan through available descriptors and choose the address

 if(!done) {

 State = RxDescState[id];
  // printf(" I am here== before small\n");
  if ( (length <= bufsz0) & vld0) {
   // check if small descriptor is available
    if ( State[0] ) {
      address = RxDescSchSMALL.getAddress(length,vaddr);
      descp_state = RxDescSchSMALL.checkState(); // Is this descriptor done?
      if(descp_state == DESCR_DONE) {
        // keep the next descriptor ready
        
	 SetIndexForReclaim();
	 RxDescSchSMALL = null;
         State[0] = 0;
         // status = popDescrs();
         if(status == -1 ) {
           printf("CRxdescpScheduler::getAddress:RDMC DEBUG DMA - %d - DONE With SMALL descriptors!! \n",id);
         }
       }
      RxToken.bufsz = 0; 
     } else {
        // Drop this packet
        RxToken.pkt_type = RNGFULL_DROP_RxPKT;
      }
 } else if ( (length <= bufsz1) & vld1) {
   // check if Medium descriptor is available
  // printf(" I am here== before medium\n");
    if ( State[1] ) {
      address = RxDescSchMEDIUM.getAddress(length,vaddr);
      descp_state = RxDescSchMEDIUM.checkState(); // Is this descriptor done?
      if(descp_state == DESCR_DONE) {
        // keep the next descriptor ready
        
	 SetIndexForReclaim();
	 RxDescSchMEDIUM = null;
         State[1] = 0;
         // status = popDescrs();
         if(status != -1) {
          printf("CRxdescpScheduler::getAddress:RDMC DEBUG DMA - %d - DONE With MEDIUM the descriptors!! \n",id);
         }
       }
      RxToken.bufsz = 1; 
     } else {
       // Drop this packet
        RxToken.pkt_type = RNGFULL_DROP_RxPKT;
       }
 } else if( (length <= bufsz2) & vld2) {
   // check if small descriptor is available
  // printf(" I am here== before large\n");
    if ( State[2] ) {
      address = RxDescSchLARGE.getAddress(length,vaddr);
      descp_state = RxDescSchLARGE.checkState(); // Is this descriptor done?
      if(descp_state == DESCR_DONE) {
        // keep the next descriptor ready
        
	 SetIndexForReclaim();
	 RxDescSchLARGE = null;
         State[2] = 0;
         // status = popDescrs();
         if(status != -1) {
          printf("CRxdescpScheduler::getAddress:RDMC  DEBUG DMA - %d - DONE With LARGE the descriptors!! \n");
         }
       }
      RxToken.bufsz = 2; 
     } else {
        // Drop this packet
        RxToken.pkt_type = RNGFULL_DROP_RxPKT;
       }
 } else {
 // This is what none of the descriptors are available
// Set packet to be dropped
    getAddress = -1; // None available
    done = 1;
    RxToken.pkt_type = RNGFULL_DROP_RxPKT;
 }

 RxToken.packet_start_address[0] = address;
 RxToken.packet_virtaddress[0] = vaddr;
 address = address + length -8 ; // this needs to be 64 bit aligned for SIU Model's memory?
 RxToken.packet_end_address[0] = {address[63:3],3'h0} ; 
 printf("CRxdescpScheduler::getAddress DMA - %d  DEBUG in getaddress before exit- endaddress - %x \n",id,address);
 RxToken.NoOfScatter = 1; 
 RxToken.bytesperchunk[0] = length;
 RxDescState[id] = State;
}

 // for(i=0;i<RxToken.NoOfScatter;i++) {
         // printf(" in getaddress before exit- endaddress - %x i - %d\n",RxToken.packet_end_address[i],i);
       // }

}