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/* dma.c -- Simulation of DMA

   Copyright (C) 2001 by Erez Volk, erez@opencores.org

   This file is part of OpenRISC 1000 Architectural Simulator.

   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., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

/*

 * This simulation of the DMA core is not meant to be full.

 * It is written only to allow simulating the Ethernet core.

 * Of course, if anyone feels like perfecting it, feel free...

 */

#include <string.h>

#include "config.h"

#ifdef HAVE_INTTYPES_H

#include <inttypes.h>

#endif

#include "port.h"

#include "arch.h"

#include "dma.h"

#include "sim-config.h"

#include "pic.h"

#include "abstract.h"

#include "fields.h"

#include "sched.h"

#include "debug.h"

DEFAULT_DEBUG_CHANNEL(dma);

/* We keep a copy of all our controllers because we have to export an interface

 * to other peripherals eg. ethernet */

static struct dma_controller *dmas = NULL;

static uint32_t dma_read32( oraddr_t addr, void *dat );

static void dma_write32( oraddr_t addr, uint32_t value, void *dat );

static unsigned long dma_read_ch_csr( struct dma_channel *channel );

static void dma_write_ch_csr( struct dma_channel *channel, unsigned long value );

void dma_controller_clock( struct dma_controller *dma );

static void dma_load_descriptor( struct dma_channel *channel );

static void dma_init_transfer( struct dma_channel *channel );

static void dma_channel_terminate_transfer( struct dma_channel *channel, int generate_interrupt );

void dma_channel_clock( void *dat );

static void masked_increase( oraddr_t *value, unsigned long mask );

#define CHANNEL_ND_I(ch) (TEST_FLAG(ch->regs.csr,DMA_CH_CSR,MODE) && TEST_FLAG(ch->regs.csr,DMA_CH_CSR,USE_ED) && ch->dma_nd_i)

/* Reset. Initializes all registers to default and places devices in memory address space. */

void dma_reset(void *dat)

{

  struct dma_controller *dma = dat;

  unsigned channel_number;

  memset( dma->ch, 0, sizeof(dma->ch) );

  dma->regs.csr = 0;

  dma->regs.int_msk_a = 0;

  dma->regs.int_msk_b = 0;

  dma->regs.int_src_a = 0;

  dma->regs.int_src_b = 0;

  for ( channel_number = 0; channel_number < DMA_NUM_CHANNELS; ++ channel_number ) {

    dma->ch[channel_number].controller = dma;

    dma->ch[channel_number].channel_number = channel_number;

    dma->ch[channel_number].channel_mask = 1LU << channel_number;

    dma->ch[channel_number].regs.am0 = dma->ch[channel_number].regs.am1 = 0xFFFFFFFC;

  }

}

/* Print register values on stdout */

void dma_status( void *dat )

{

  unsigned j;

  struct dma_controller *dma = dat;

  if ( dma->baseaddr == 0 )

    return;

  PRINTF( "\nDMA controller at 0x%"PRIxADDR":\n", dma->baseaddr );

  PRINTF( "CSR       : 0x%08lX\n", dma->regs.csr );

  PRINTF( "INT_MSK_A : 0x%08lX\n", dma->regs.int_msk_a );

  PRINTF( "INT_MSK_B : 0x%08lX\n", dma->regs.int_msk_b );

  PRINTF( "INT_SRC_A : 0x%08lX\n", dma->regs.int_src_a );

  PRINTF( "INT_SRC_B : 0x%08lX\n", dma->regs.int_src_b );

  for ( j = 0; j < DMA_NUM_CHANNELS; ++ j ) {

    struct dma_channel *channel = &(dma->ch[j]);

    if ( !channel->referenced )

      continue;

    PRINTF( "CH%u_CSR   : 0x%08lX\n", j, channel->regs.csr );

    PRINTF( "CH%u_SZ    : 0x%08lX\n", j, channel->regs.sz );

    PRINTF( "CH%u_A0    : 0x%08lX\n", j, channel->regs.a0 );

    PRINTF( "CH%u_AM0   : 0x%08lX\n", j, channel->regs.am0 );

    PRINTF( "CH%u_A1    : 0x%08lX\n", j, channel->regs.a1 );

    PRINTF( "CH%u_AM1   : 0x%08lX\n", j, channel->regs.am1 );

    PRINTF( "CH%u_DESC  : 0x%08lX\n", j, channel->regs.desc );

    PRINTF( "CH%u_SWPTR : 0x%08lX\n", j, channel->regs.swptr );

  }

}

/* Read a register */

uint32_t dma_read32( oraddr_t addr, void *dat )

{

  struct dma_controller *dma = dat;

  if ( addr < DMA_CH_BASE ) {

    /* case of global (not per-channel) registers */

    switch( addr ) {

    case DMA_CSR: return dma->regs.csr;

    case DMA_INT_MSK_A: return dma->regs.int_msk_a;

    case DMA_INT_MSK_B: return dma->regs.int_msk_b;

    case DMA_INT_SRC_A: return dma->regs.int_src_a;

    case DMA_INT_SRC_B: return dma->regs.int_src_b;

    default:

      fprintf( stderr, "dma_read32( 0x%"PRIxADDR" ): Illegal register\n",

               addr + dma->baseaddr );

      return 0;

    }

  } else {

    /* case of per-channel registers */

    unsigned chno = (addr - DMA_CH_BASE) / DMA_CH_SIZE;

    addr = (addr - DMA_CH_BASE) % DMA_CH_SIZE;

    switch( addr ) {

    case DMA_CH_CSR: return dma_read_ch_csr( &(dma->ch[chno]) );

    case DMA_CH_SZ: return dma->ch[chno].regs.sz;

    case DMA_CH_A0: return dma->ch[chno].regs.a0;

    case DMA_CH_AM0: return dma->ch[chno].regs.am0;

    case DMA_CH_A1: return dma->ch[chno].regs.a1;

    case DMA_CH_AM1: return dma->ch[chno].regs.am1;

    case DMA_CH_DESC: return dma->ch[chno].regs.desc;

    case DMA_CH_SWPTR: return dma->ch[chno].regs.swptr;

    }

  }

  return 0;

}

/* Handle read from a channel CSR */

unsigned long dma_read_ch_csr( struct dma_channel *channel )

{

  unsigned long result = channel->regs.csr;

  /* before returning, clear all relevant bits */

  CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, INT_CHUNK_DONE );

  CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, INT_DONE );

  CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, INT_ERR );

  CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, ERR );

  return result;

}

/* Write a register */

void dma_write32( oraddr_t addr, uint32_t value, void *dat )

{

  struct dma_controller *dma = dat;

  /* case of global (not per-channel) registers */

  if ( addr < DMA_CH_BASE ) {

    switch( addr ) {

    case DMA_CSR:

      if ( TEST_FLAG( value, DMA_CSR, PAUSE ) )

        fprintf( stderr, "dma: PAUSE not implemented\n" );

      break;

    case DMA_INT_MSK_A: dma->regs.int_msk_a = value; break;

    case DMA_INT_MSK_B: dma->regs.int_msk_b = value; break;

    case DMA_INT_SRC_A: dma->regs.int_src_a = value; break;

    case DMA_INT_SRC_B: dma->regs.int_src_b = value; break;

    default:

      fprintf( stderr, "dma_write32( 0x%"PRIxADDR" ): Illegal register\n",

               addr + dma->baseaddr );

      return;

    }

  } else {

    /* case of per-channel registers */

    unsigned chno = (addr - DMA_CH_BASE) / DMA_CH_SIZE;

    struct dma_channel *channel = &(dma->ch[chno]);

    channel->referenced = 1;

    addr = (addr - DMA_CH_BASE) % DMA_CH_SIZE;

    switch( addr ) {

    case DMA_CSR: dma_write_ch_csr( &(dma->ch[chno]), value ); break;

    case DMA_CH_SZ: channel->regs.sz = value; break;

    case DMA_CH_A0: channel->regs.a0 = value; break;

    case DMA_CH_AM0: channel->regs.am0 = value; break;

    case DMA_CH_A1: channel->regs.a1 = value; break;

    case DMA_CH_AM1: channel->regs.am1 = value; break;

    case DMA_CH_DESC: channel->regs.desc = value; break;

    case DMA_CH_SWPTR: channel->regs.swptr = value; break;

    }

  }

}

/* Write a channel CSR

 * This ensures only the writable bits are modified.

 */

void dma_write_ch_csr( struct dma_channel *channel, unsigned long value )

{

  /* Check if we should *start* a transfer */

  if ( !TEST_FLAG( channel->regs.csr, DMA_CH_CSR, CH_EN ) &&

       TEST_FLAG( value, DMA_CH_CSR, CH_EN ))

    SCHED_ADD( dma_channel_clock, channel, 1 );

  else if ( !TEST_FLAG( value, DMA_CH_CSR, CH_EN ) )

    /* The CH_EN flag is clear, check if we have a transfer in progress and

     * clear it */

    SCHED_FIND_REMOVE( dma_channel_clock, channel );

  /* Copy the writable bits to the channel CSR */

  channel->regs.csr &= ~DMA_CH_CSR_WRITE_MASK;

  channel->regs.csr |= value & DMA_CH_CSR_WRITE_MASK;

}

/* Clock tick for one channel on one DMA controller.

 * This does the actual "DMA" operation.

 * One chunk is transferred per clock.

 */

void dma_channel_clock( void *dat )

{

  struct dma_channel *channel = dat;

  /* Do we need to abort? */

  if ( TEST_FLAG( channel->regs.csr, DMA_CH_CSR, STOP ) ) {

    TRACE( "DMA: STOP requested\n" );

    CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, CH_EN );

    CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, BUSY );

    SET_FLAG( channel->regs.csr, DMA_CH_CSR, ERR );

    if ( TEST_FLAG( channel->regs.csr, DMA_CH_CSR, INE_ERR ) &&

         (channel->controller->regs.int_msk_a & channel->channel_mask) ) {

      SET_FLAG( channel->regs.csr, DMA_CH_CSR, INT_ERR );

      channel->controller->regs.int_src_a = channel->channel_mask;

      report_interrupt( channel->controller->irq );

    }

    return;

  }

  /* In HW Handshake mode, only work when dma_req_i asserted */

  if ( TEST_FLAG(channel->regs.csr, DMA_CH_CSR, MODE) && !channel->dma_req_i ) {

    /* Reschedule */

    SCHED_ADD( dma_channel_clock, dat, 1 );

    return;

  }

  /* If this is the first cycle of the transfer, initialize our state */

  if ( !TEST_FLAG( channel->regs.csr, DMA_CH_CSR, BUSY ) ) {

    TRACE( "DMA: Starting new transfer\n" );

    CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, DONE );

    CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, ERR );

    SET_FLAG( channel->regs.csr, DMA_CH_CSR, BUSY );

    /* If using linked lists, copy the appropriate fields to our registers */

    if ( TEST_FLAG( channel->regs.csr, DMA_CH_CSR, USE_ED ) )

      dma_load_descriptor( channel );

    else

      channel->load_next_descriptor_when_done = 0;

    /* Set our internal status */

    dma_init_transfer( channel );

    /* Might need to skip descriptor */

    if ( CHANNEL_ND_I( channel ) ) {

      TRACE( "DMA: dma_nd_i asserted before dma_req_i, skipping descriptor\n" );

      dma_channel_terminate_transfer( channel, 0 );

      return;

    }

  }

  /* Transfer one word */

  set_direct32( channel->destination, eval_direct32( channel->source, 0, 0 ),

                0, 0 );

  /* Advance the source and destionation pointers */

  masked_increase( &(channel->source), channel->source_mask );

  masked_increase( &(channel->destination), channel->destination_mask );

  ++ channel->words_transferred;

  /* Have we finished a whole chunk? */

  channel->dma_ack_o = (channel->words_transferred % channel->chunk_size == 0);

  /* When done with a chunk, check for dma_nd_i */

  if ( CHANNEL_ND_I( channel ) ) {

    TRACE( "DMA: dma_nd_i asserted\n" );

    dma_channel_terminate_transfer( channel, 0 );

    return;

  }

  /* Are we done? */

  if ( channel->words_transferred >= channel->total_size ) {

    dma_channel_terminate_transfer( channel, 1 );

    return;

  }

  /* Reschedule to transfer the next chunk */

  SCHED_ADD( dma_channel_clock, dat, 1 );

}

/* Copy relevant valued from linked list descriptor to channel registers */

void dma_load_descriptor( struct dma_channel *channel )

{

  unsigned long desc_csr = eval_direct32( channel->regs.desc + DMA_DESC_CSR, 0, 0 );

  channel->load_next_descriptor_when_done = !TEST_FLAG( desc_csr, DMA_DESC_CSR, EOL );

  ASSIGN_FLAG( channel->regs.csr, DMA_CH_CSR, INC_SRC, TEST_FLAG( desc_csr, DMA_DESC_CSR, INC_SRC ) );

  ASSIGN_FLAG( channel->regs.csr, DMA_CH_CSR, INC_DST, TEST_FLAG( desc_csr, DMA_DESC_CSR, INC_DST ) );

  ASSIGN_FLAG( channel->regs.csr, DMA_CH_CSR, SRC_SEL, TEST_FLAG( desc_csr, DMA_DESC_CSR, SRC_SEL ) );

  ASSIGN_FLAG( channel->regs.csr, DMA_CH_CSR, DST_SEL, TEST_FLAG( desc_csr, DMA_DESC_CSR, DST_SEL ) );

  SET_FIELD( channel->regs.sz, DMA_CH_SZ, TOT_SZ,        GET_FIELD( desc_csr, DMA_DESC_CSR, TOT_SZ ) );

  channel->regs.a0 = eval_direct32( channel->regs.desc + DMA_DESC_ADR0, 0, 0 );

  channel->regs.a1 = eval_direct32( channel->regs.desc + DMA_DESC_ADR1, 0, 0 );

  channel->current_descriptor = channel->regs.desc;

  channel->regs.desc = eval_direct32( channel->regs.desc + DMA_DESC_NEXT, 0, 0 );

}

/* Initialize internal parameters used to implement transfers */

void dma_init_transfer( struct dma_channel *channel )

{

  channel->source = channel->regs.a0;

  channel->destination = channel->regs.a1;

  channel->source_mask = TEST_FLAG( channel->regs.csr, DMA_CH_CSR, INC_SRC ) ? channel->regs.am0 : 0;

  channel->destination_mask = TEST_FLAG( channel->regs.csr, DMA_CH_CSR, INC_DST ) ? channel->regs.am1 : 0;

  channel->total_size = GET_FIELD( channel->regs.sz, DMA_CH_SZ, TOT_SZ );

  channel->chunk_size = GET_FIELD( channel->regs.sz, DMA_CH_SZ, CHK_SZ );

  if ( !channel->chunk_size || (channel->chunk_size > channel->total_size) )

    channel->chunk_size = channel->total_size;

  channel->words_transferred = 0;

}

/* Take care of transfer termination */

void dma_channel_terminate_transfer( struct dma_channel *channel, int generate_interrupt )

{

  TRACE( "DMA: Terminating transfer\n" );

  /* Might be working in a linked list */

  if ( channel->load_next_descriptor_when_done ) {

    dma_load_descriptor( channel );

    dma_init_transfer( channel );

    /* Reschedule */

    SCHED_ADD( dma_channel_clock, channel, 1 );

    return;

  }

  /* Might be in auto-restart mode */

  if ( TEST_FLAG( channel->regs.csr, DMA_CH_CSR, ARS ) ) {

    dma_init_transfer( channel );

    return;

  }

  /* If needed, write amount of data transferred back to memory */

  if ( TEST_FLAG( channel->regs.csr, DMA_CH_CSR, SZ_WB ) &&

       TEST_FLAG( channel->regs.csr, DMA_CH_CSR, USE_ED ) ) {

   /* TODO: What should we write back? Doc says "total number of remaining bytes" !? */

    unsigned long remaining_words = channel->total_size - channel->words_transferred;

    SET_FIELD( channel->regs.sz, DMA_DESC_CSR, TOT_SZ, remaining_words );

  }

  /* Mark end of transfer */

  CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, CH_EN );

  SET_FLAG( channel->regs.csr, DMA_CH_CSR, DONE );

  CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, ERR );

  CLEAR_FLAG( channel->regs.csr, DMA_CH_CSR, BUSY );

  /* If needed, generate interrupt */

  if ( generate_interrupt ) {

    /* TODO: Which channel should we interrupt? */

    if ( TEST_FLAG( channel->regs.csr, DMA_CH_CSR, INE_DONE ) &&

         (channel->controller->regs.int_msk_a & channel->channel_mask) ) {

      SET_FLAG( channel->regs.csr, DMA_CH_CSR, INT_DONE );

      channel->controller->regs.int_src_a = channel->channel_mask;

      report_interrupt( channel->controller->irq );

    }

  }

}

/* Utility function: Add 4 to a value with a mask */

static void masked_increase( oraddr_t *value, unsigned long mask )

{

  *value = (*value & ~mask) | ((*value + 4) & mask);

}

/*-------------------------------------------[ DMA<->Peripheral interface ]---*/

/*

 * Simulation of control signals

 * To be used by simulations for other devices, e.g. ethernet

 */

void set_dma_req_i( struct dma_channel *channel )

{

  channel->dma_req_i = 1;

}

void clear_dma_req_i( struct dma_channel *channel )

{

  channel->dma_req_i = 0;

}

void set_dma_nd_i( struct dma_channel *channel )

{

  channel->dma_nd_i = 1;

}

void clear_dma_nd_i( struct dma_channel *channel )

{

  channel->dma_nd_i = 0;

}

unsigned check_dma_ack_o( struct dma_channel *channel )

{

  return channel->dma_ack_o;

}

struct dma_channel *find_dma_controller_ch( unsigned controller,

                                            unsigned channel )

{

  struct dma_controller *cur = dmas;

  while( cur && controller ) {

    cur = cur->next;

    controller--;

  }

  if( !cur )

    return NULL;

  return &(cur->ch[channel]);

}

/*----------------------------------------------------[ DMA configuration ]---*/

static void dma_baseaddr(union param_val val, void *dat)

{

  struct dma_controller *dma = dat;

  dma->baseaddr = val.addr_val;

}

static void dma_irq(union param_val val, void *dat)

{

  struct dma_controller *dma = dat;

  dma->irq = val.int_val;

}

static void dma_vapi_id(union param_val val, void *dat)

{

  struct dma_controller *dma = dat;

  dma->vapi_id = val.int_val;

}

static void dma_enabled(union param_val val, void *dat)

{

  struct dma_controller *dma = dat;

  dma->enabled = val.int_val;

}

static void *dma_sec_start(void)

{

  struct dma_controller *new = malloc(sizeof(struct dma_controller));

  if(!new) {

    fprintf(stderr, "Peripheral DMA: Run out of memory\n");

    exit(-1);

  }

  new->next = NULL;

  new->enabled = 1;

  return new;

}

static void dma_sec_end(void *dat)

{

  struct dma_controller *dma = dat;

  struct dma_controller *cur;

  struct mem_ops ops;

  if(!dma->enabled) {

    free(dat);

    return;

  }

  memset(&ops, 0, sizeof(struct mem_ops));

  ops.readfunc32 = dma_read32;

  ops.writefunc32 = dma_write32;

  ops.read_dat32 = dat;

  ops.write_dat32 = dat;

  /* FIXME: Correct delay?? */

  ops.delayr = 2;

  ops.delayw = 2;

  reg_mem_area( dma->baseaddr, DMA_ADDR_SPACE, 0, &ops );

  reg_sim_reset( dma_reset, dat );

  reg_sim_stat( dma_status, dat );

  if(dmas) {

    for(cur = dmas; cur->next; cur = cur->next);

    cur->next = dma;

  } else

    dmas = dma;

}

void reg_dma_sec(void)

{

  struct config_section *sec = reg_config_sec("dma", dma_sec_start, dma_sec_end);

  reg_config_param(sec, "irq", paramt_int, dma_irq);

  reg_config_param(sec, "enabled", paramt_int, dma_enabled);

  reg_config_param(sec, "baseaddr", paramt_addr, dma_baseaddr);

  reg_config_param(sec, "vapi_id", paramt_addr, dma_vapi_id);

}