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/* 16450.c -- Simulation of 8250/16450 serial UART
   Copyright (C) 1999 Damjan Lampret, lampret@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 is functional simulation of 8250/16450 UARTs. Since we RX/TX data
   via file streams, we can't simulate modem control lines coming from the
   DCE and similar details of communication with the DCE.
 
   This simulated UART device is intended for basic UART device driver
   verification. From device driver perspective this device looks like a
   regular UART but never reports and modem control lines changes (the
   only DCE responses are incoming characters from the file stream).
*/
 
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
 
#include "abstract.h"
#include "16450.h"
#include "sim-config.h"
#include "pic.h"
#include "vapi.h"
#include "sched.h"
#include "channel.h"
#include "debug.h"
 
#define MIN(a,b) ((a) < (b) ? (a) : (b))
 
static struct dev_16450 uarts[MAX_UARTS];                       /* simulation info */
static struct channel * channels[MAX_UARTS] = { NULL, };        /* emulation info */
 
/* Number of clock cycles (one clock cycle is one call to the uart_clock())
   before a single character is transmitted or received. */
static unsigned long char_clks(int dll, int dlh, int lcr)
{
  float bauds_per_char = 1.;
  unsigned long char_clks = ((dlh << 8) + dll);
 
  if (lcr & UART_LCR_PARITY)
    bauds_per_char = bauds_per_char + 1.;
 
  /* stop bits 1 or two */
  if (lcr & UART_LCR_STOP)
    bauds_per_char = bauds_per_char + 2.;
  else
    if ((lcr & 0x3) != 0)
      bauds_per_char = bauds_per_char + 1.;
    else
      bauds_per_char = bauds_per_char + 1.5;
 
  bauds_per_char = bauds_per_char + (5. + (lcr & 0x3));
 
  return char_clks * bauds_per_char;
}
 
/* Set a specific UART register with value. */
void uart_write_byte(unsigned long addr, unsigned long value)
{
  int chipsel;
 
  debug(4, "uart_write_byte(%x,%02x)\n", addr, (unsigned)value);
 
  for(chipsel = 0; chipsel < MAX_UARTS; chipsel++)
    if ((addr & ~(UART_ADDR_SPACE-1)) == config.uarts[chipsel].baseaddr)
      break;
  if (chipsel >= MAX_UARTS) return;
 
  if (uarts[chipsel].regs.lcr & UART_LCR_DLAB) {
    switch (addr % UART_ADDR_SPACE) {
      case UART_DLL:
        uarts[chipsel].regs.dll = value;
        uarts[chipsel].char_clks = char_clks(uarts[chipsel].regs.dll, uarts[chipsel].regs.dlh, uarts[chipsel].regs.lcr);
        return;
      case UART_DLH:
        uarts[chipsel].regs.dlh = value;
        return;
    }
  }
 
  switch (addr % UART_ADDR_SPACE) {
    case UART_TXBUF:
      if (uarts[chipsel].istat.txbuf_full < uarts[chipsel].fifo_len) {
        uarts[chipsel].istat.txbuf_full++;
        uarts[chipsel].regs.txbuf[uarts[chipsel].istat.txbuf_head] = value;
        uarts[chipsel].istat.txbuf_head = (uarts[chipsel].istat.txbuf_head + 1) % uarts[chipsel].fifo_len;
      } else
        uarts[chipsel].regs.txbuf[uarts[chipsel].istat.txbuf_head] = value;
 
      uarts[chipsel].regs.lsr &= ~(UART_LSR_TXSERE | UART_LSR_TXBUFE);
      if (uarts[chipsel].regs.iir & UART_IIR_THRI)
        uarts[chipsel].istat.thre_int = 0;
      break;
    case UART_FCR:
      uarts[chipsel].regs.fcr = value & UART_VALID_FCR;
      if (uarts[chipsel].fifo_len == 1 && (value & UART_FCR_FIE)
       || uarts[chipsel].fifo_len != 1 && !(value & UART_FCR_FIE))
        value |= UART_FCR_RRXFI | UART_FCR_RTXFI;
      uarts[chipsel].fifo_len = (value & UART_FCR_FIE) ? 16 : 1;
      if (value & UART_FCR_RTXFI) {
        uarts[chipsel].istat.txbuf_head = uarts[chipsel].istat.txbuf_tail = 0;
        uarts[chipsel].istat.txbuf_full = 0;
        uarts[chipsel].regs.lsr |= UART_LSR_TXBUFE;
 
        // For FIFO-mode only, THRE interrupt is set when THR and FIFO are empty
        uarts[chipsel].istat.thre_int = (uarts[chipsel].fifo_len == 16);
      }
      if (value & UART_FCR_RRXFI) {
        uarts[chipsel].istat.rxbuf_head = uarts[chipsel].istat.rxbuf_tail = 0;
        uarts[chipsel].istat.rxbuf_full = 0;
        uarts[chipsel].regs.lsr &= ~UART_LSR_RDRDY;
      }
      break;
    case UART_IER:
      uarts[chipsel].regs.ier = value & UART_VALID_IER;
      break;
    case UART_LCR:
      uarts[chipsel].regs.lcr = value & UART_VALID_LCR;
      uarts[chipsel].char_clks = char_clks(uarts[chipsel].regs.dll, uarts[chipsel].regs.dlh, uarts[chipsel].regs.lcr);
      break;
    case UART_MCR:
      uarts[chipsel].regs.mcr = value & UART_VALID_MCR;
      break;
    case UART_SCR:
      uarts[chipsel].regs.scr = value;
      break;
    default:
      debug(1, "write out of range (addr %x)\n", addr);
  }
}
 
/* Read a specific UART register. */
unsigned long uart_read_byte(unsigned long addr)
{
  unsigned char value = 0;
  int chipsel;
 
  debug(4, "uart_read_byte(%x)", addr);
 
  for(chipsel = 0; chipsel < MAX_UARTS; chipsel++)
    if ((addr & ~(UART_ADDR_SPACE-1)) == config.uarts[chipsel].baseaddr)
      break;
 
  if (chipsel >= MAX_UARTS)
    return 0;
 
  if (uarts[chipsel].regs.lcr & UART_LCR_DLAB) {
    switch (addr % UART_ADDR_SPACE) {
      case UART_DLL:
        value = uarts[chipsel].regs.dll;
        debug(4, "= %x\n", value);
        return value;
      case UART_DLH:
        value = uarts[chipsel].regs.dlh;
        debug(4, "= %x\n", value);
        return value;
    }
  }
 
  switch (addr % UART_ADDR_SPACE) {
    case UART_RXBUF:
      { /* Print out FIFO for debugging */
        int i;
        debug(4, "(%i/%i,%i,%i:", uarts[chipsel].istat.rxbuf_full, uarts[chipsel].fifo_len,
                  uarts[chipsel].istat.rxbuf_head, uarts[chipsel].istat.rxbuf_tail);
        for (i = 0; i < uarts[chipsel].istat.rxbuf_full; i++)
          debug(4, "%02x ", uarts[chipsel].regs.rxbuf[(uarts[chipsel].istat.rxbuf_tail + i) % uarts[chipsel].fifo_len]);
        debug(4, ")");
      }
      if (uarts[chipsel].istat.rxbuf_full) {
        value = uarts[chipsel].regs.rxbuf[uarts[chipsel].istat.rxbuf_tail];
        uarts[chipsel].istat.rxbuf_tail = (uarts[chipsel].istat.rxbuf_tail + 1) % uarts[chipsel].fifo_len;
        uarts[chipsel].istat.rxbuf_full--;
      }
 
      if (uarts[chipsel].istat.rxbuf_full)
        uarts[chipsel].regs.lsr |= UART_LSR_RDRDY;
      else
        uarts[chipsel].regs.lsr &= ~UART_LSR_RDRDY;
 
      uarts[chipsel].istat.timeout_count = 0;
      break;
    case UART_IER:
      value = uarts[chipsel].regs.ier & UART_VALID_IER;
      break;
    case UART_IIR:
      value = (uarts[chipsel].regs.iir & UART_VALID_IIR) | 0xc0;
      if (uarts[chipsel].regs.iir & UART_IIR_THRI)
        uarts[chipsel].istat.thre_int = 0;
      break;
    case UART_LCR:
      value = uarts[chipsel].regs.lcr & UART_VALID_LCR;
      break;
    case UART_MCR:
      value = 0;
      break;
    case UART_LSR:
      value = uarts[chipsel].regs.lsr & UART_VALID_LSR;
      uarts[chipsel].regs.lsr &=
        ~(UART_LSR_OVRRUN | UART_LSR_BREAK | UART_LSR_PARITY
         | UART_LSR_FRAME | UART_LSR_RXERR);
      break;
    case UART_MSR:
      value = uarts[chipsel].regs.msr & UART_VALID_MSR;
      uarts[chipsel].regs.msr = 0;
      break;
    case UART_SCR:
      value = uarts[chipsel].regs.scr;
      break;
    default:
      debug(1, "read out of range (addr %x)\n", addr);
  }
  debug(4, " = %x\n", value);
  return value;
}
 
/* Function that handles incoming VAPI data.  */
void uart_vapi_read (unsigned long id, unsigned long data)
{
  int uart;
  debug(4, "UART: id %08x, data %08x\n", id, data);
  uart = id & VAPI_DEVICE_ID;
  uarts[uart].vapi_buf[uarts[uart].vapi_buf_head_ptr] = data;
  uarts[uart].vapi_buf_head_ptr = (uarts[uart].vapi_buf_head_ptr + 1) % UART_VAPI_BUF_LEN;
  if (uarts[uart].vapi_buf_tail_ptr == uarts[uart].vapi_buf_head_ptr) {
    fprintf (stderr, "FATAL: uart VAPI buffer to small.\n");
    exit (1);
  }
}
 
static void send_char (int uart, int bits_send)
{
  PRINTF ("%c", uarts[uart].iregs.txser);
  debug(4, "TX \'%c\' via UART%d...\n", uarts[uart].iregs.txser, uart);
  if (uarts[uart].regs.mcr & UART_MCR_LOOP)
    uarts[uart].iregs.loopback = uarts[uart].iregs.txser;
  else {
    /* Send to either VAPI or to file */
    if (config.uarts[uart].vapi_id) {
      int par, pe, fe, nbits;
      int j, data;
      unsigned long packet = 0;
 
      nbits = MIN (bits_send, (uarts[uart].regs.lcr & UART_LCR_WLEN8) + 5);
      /* Encode a packet */
      packet = uarts[uart].iregs.txser & ((1 << nbits) - 1);
 
      /* Calculate parity */
      for (j = 0, par = 0; j < nbits; j++)
        par ^= (packet >> j) & 1;
 
      if (uarts[uart].regs.lcr & UART_LCR_PARITY) {
        if (uarts[uart].regs.lcr & UART_LCR_SPAR) {
          packet |= 1 << nbits;
        } else {
          if (uarts[uart].regs.lcr & UART_LCR_EPAR)
            packet |= par << nbits;
          else
            packet |= (par ^ 1) << nbits;
        }
        nbits++;
      }
      packet |= 1 << (nbits++);
      if (uarts[uart].regs.lcr & UART_LCR_STOP)
        packet |= 1 << (nbits++);
 
      /* Decode a packet */
      nbits = (uarts[uart].vapi.lcr & UART_LCR_WLEN8) + 5;
      data = packet & ((1 << nbits) - 1);
 
      /* Calculate parity, including parity bit */
      for (j = 0, par = 0; j < nbits + 1; j++)
        par ^= (packet >> j) & 1;
 
      if (uarts[uart].vapi.lcr & UART_LCR_PARITY) {
        if (uarts[uart].vapi.lcr & UART_LCR_SPAR) {
          pe = !((packet >> nbits) & 1);
        } else {
          if (uarts[uart].vapi.lcr & UART_LCR_EPAR)
            pe = par != 0;
          else
            pe = par != 1;
        }
        nbits++;
      } else
        pe = 0;
 
      fe = ((packet >> (nbits++)) & 1) ^ 1;
      if (uarts[uart].vapi.lcr & UART_LCR_STOP)
        fe |= ((packet >> (nbits++)) & 1) ^ 1;
 
      debug (4, "lcr vapi %02x, uart %02x\n", uarts[uart].vapi.lcr, uarts[uart].regs.lcr);
      data |= (uarts[uart].vapi.lcr << 8) | (pe << 16) | (fe << 17) | (uarts[uart].vapi.lcr << 8);
      PRINTF ("vapi_send (%08lx, %08x)\n", config.uarts[uart].vapi_id, data);
      debug (4, "vapi_send (%08x, %08x)\n", config.uarts[uart].vapi_id, data);
      vapi_send (config.uarts[uart].vapi_id, data);
    } else {
      char buffer[1] = { uarts[uart].iregs.txser & 0xFF };
      channel_write(channels[uart], buffer, 1);
    }
  }
  uarts[uart].istat.txser_full = 0;
  uarts[uart].istat.txser_clks = 0;
}
 
/* Adds a character to the FIFO */
 
void uart_add_char (int uart, int ch)
{
  if (uarts[uart].istat.rxbuf_full + 1 > uarts[uart].fifo_len)
    uarts[uart].regs.lsr |= UART_LSR_OVRRUN | UART_LSR_RXERR;
  else {
    debug(4, "add %02x\n", ch);
    uarts[uart].regs.rxbuf[uarts[uart].istat.rxbuf_head] = ch;
    uarts[uart].istat.rxbuf_head = (uarts[uart].istat.rxbuf_head + 1) % uarts[uart].fifo_len;
    uarts[uart].istat.rxbuf_full++;
  }
  uarts[uart].regs.lsr |= UART_LSR_RDRDY;
  uarts[uart].istat.timeout_count = 0;
}
 
/* Simulation hook. Must be called every clock cycle to simulate all UART
   devices. It does internal functional UART simulation. */
void uart_clock16 (int i)
{
  int retval;
 
  /* Schedule for later */
  SCHED_ADD (uart_clock16, i, runtime.sim.cycles + UART_CLOCK_DIVIDER);
 
  /* If VAPI is not selected, UART communicates with two file streams;
     if VAPI is selected, we use VAPI streams.  */
  /* if txfs is corrupted, skip this uart. */
  if (!config.uarts[i].vapi_id && !channel_ok(channels[i])) return;
 
  if (uarts[i].vapi.next_break_cnt >= 0)
    if (--uarts[i].vapi.next_break_cnt < 0) {
      if (!(uarts[i].vapi.cur_break = uarts[i].vapi.next_break))
        uarts[i].istat.break_set = 0;
    }
 
  /***************** Transmit *****************/
  if (!uarts[i].istat.txser_full) {
//      uarts[i].regs.lsr |= UART_LSR_TXBUFE;
    if (uarts[i].istat.txbuf_full) {
      uarts[i].iregs.txser = uarts[i].regs.txbuf[uarts[i].istat.txbuf_tail];
      uarts[i].istat.txbuf_tail = (uarts[i].istat.txbuf_tail + 1) % uarts[i].fifo_len;
      uarts[i].istat.txser_full = 1;
      uarts[i].istat.txbuf_full--;
      uarts[i].regs.lsr &= ~UART_LSR_TXSERE;
 
      // When UART is in either character mode, i.e. 16450 emulation mode, or FIFO mode,
      // the THRE interrupt is raised when THR transitions from full to empty.
      if (!uarts[i].istat.txbuf_full) {
        uarts[i].istat.thre_int = 1;
        uarts[i].regs.lsr |= UART_LSR_TXBUFE;
      }
    } else {
      uarts[i].regs.lsr |= UART_LSR_TXSERE;
    }
  } else if (uarts[i].char_clks <= uarts[i].istat.txser_clks++) {
    send_char(i, (uarts[i].regs.lcr & UART_LCR_WLEN8) + 5); /* We've sent all bits */
  } else {
    /* We are still sending char here*/
 
    /* Check if we set the break bit */
    if (uarts[i].regs.lcr & UART_LCR_SBC) {
      if (!uarts[i].vapi.break_sent) {
#if 0
        /* Send broken frame */
        int nbits_sent = ((uarts[i].regs.lcr & UART_LCR_WLEN8) + 5) * (uarts[i].istat.txser_clks - 1) / uarts[i].char_clks;
        send_char(i, nbits_sent);
#endif
        /* Send one break signal */
        vapi_send (config.uarts[i].vapi_id, UART_LCR_SBC << 8);
        uarts[i].vapi.break_sent = 1;
      }
      /* mark as character was sent */
      uarts[i].istat.txser_full = 0;
      uarts[i].istat.txser_clks = 0;
    } else
      uarts[i].vapi.break_sent = 0;
 
  }
 
  /***************** Receive *****************/
 
  /* Is there a break? */
  if (uarts[i].vapi.cur_break) {
    uarts[i].vapi.cur_break_cnt++;
    if (uarts[i].vapi.cur_break_cnt > UART_BREAK_COUNT * uarts[i].vapi.char_clks) {
      if (!uarts[i].istat.break_set) {
        unsigned lsr;
        uarts[i].istat.break_set = 1;
        lsr = UART_LSR_BREAK | UART_LSR_RXERR | UART_LSR_RDRDY;
        PRINTF ("[%x]\n", uarts[i].regs.lsr);
        uarts[i].istat.rxser_full = 0;
        uarts[i].istat.rxser_clks = 0;
        uart_add_char (i, lsr << 8);
      } else
        uarts[i].vapi.cur_break_cnt = 0;
    }
    if (uarts[i].istat.rxser_full) {
      uarts[i].istat.rxser_full = 0;
      uarts[i].istat.rxser_clks = 0;
    }
  } else {
    if (uarts[i].istat.rxser_full) {
      if (uarts[i].char_clks <= uarts[i].istat.rxser_clks++) {
        /* Set unused character bits to zero and allow lsr register in fifo */
        uarts[i].iregs.rxser &= ((1 << ((uarts[i].regs.lcr & 3) + 5)) - 1) | 0xff00;
        debug(4, "Receiving 0x%02x'%c' via UART%d...\n", uarts[i].iregs.rxser,
              uarts[i].iregs.rxser, i);
        PRINTF ("%c", uarts[i].iregs.rxser);
        uarts[i].istat.rxser_full = 0;
        uarts[i].istat.rxser_clks = 0;
        uart_add_char (i, uarts[i].iregs.rxser);
      }
    }
  }
 
  /* Check if there is something waiting, and put it into rxser */
  if (uarts[i].regs.mcr & UART_MCR_LOOP) {
    uarts[i].iregs.rxser = uarts[i].iregs.loopback;
    uarts[i].istat.rxser_full = 1;
  } else {
    if (!config.uarts[i].vapi_id) {
      if(uarts[i].istat.rxser_full == 0) {
        if (uarts[i].slowdown)
          uarts[i].slowdown--;
        else {
          char buffer[1];
          retval = channel_read(channels[i], buffer, 1);
          if(retval < 0)
                  perror(config.uarts[i].channel);
          else if(retval > 0) {
            uarts[i].iregs.rxser = (unsigned char)buffer[0];
            uarts[i].istat.rxser_full = 1;
          } else
            uarts[i].slowdown = UART_FGETC_SLOWDOWN;
        }
      }
    } else { /* VAPI */
      int received = 0;
      /* do not handle commands while receiving */
      if (uarts[i].istat.rxser_full) return;
      while (!received) {
        if (uarts[i].vapi_buf_head_ptr != uarts[i].vapi_buf_tail_ptr) {
          unsigned long data = uarts[i].vapi_buf[uarts[i].vapi_buf_tail_ptr];
          debug(4, "Handling: %08x (%i,%i)\n", data, uarts[i].vapi_buf_head_ptr, uarts[i].vapi_buf_tail_ptr);
          uarts[i].vapi_buf_tail_ptr = (uarts[i].vapi_buf_tail_ptr + 1) % UART_VAPI_BUF_LEN;
          switch (data >> 24) {
            case 0x00:
              uarts[i].vapi.lcr = (data >> 8) & 0xff;
              /* Put data into rx fifo */
              uarts[i].iregs.rxser = data & 0xff;
              uarts[i].vapi.char_clks = char_clks (uarts[i].vapi.dll, uarts[i].vapi.dlh, uarts[i].vapi.lcr);
              if ((uarts[i].vapi.lcr & ~UART_LCR_SBC) != (uarts[i].regs.lcr & ~UART_LCR_SBC)
               || uarts[i].vapi.char_clks != uarts[i].char_clks
               || uarts[i].vapi.skew < -MAX_SKEW || uarts[i].vapi.skew > MAX_SKEW) {
                debug (3, "WARNING: unmatched VAPI (%02x) and uart (%02x) modes.\n",
                      uarts[i].vapi.lcr & ~UART_LCR_SBC, uarts[i].regs.lcr & ~UART_LCR_SBC);
                /* Set error bits */
                uarts[i].iregs.rxser |= (UART_LSR_FRAME | UART_LSR_RXERR) << 8;
                if (uarts[i].regs.lcr & UART_LCR_PARITY) uarts[i].iregs.rxser |= UART_LSR_PARITY << 8;
              }
              uarts[i].istat.rxser_full = 1;
              received = 1;
              break;
            case 0x01:
              uarts[i].vapi.dll = (data >> 0) & 0xff;
              uarts[i].vapi.dlh = (data >> 8) & 0xff;
              break;
            case 0x02:
              uarts[i].vapi.lcr = (data >> 8) & 0xff;
              break;
            case 0x03:
              uarts[i].vapi.skew = (signed short)(data & 0xffff);
              break;
            case 0x04:
              uarts[i].vapi.next_break_cnt = data & 0xffff;
              uarts[i].vapi.next_break = (data >> 16) & 1;
              break;
            default:
              debug (0, "WARNING: Invalid vapi command %02x\n", data >> 24);
              break;
          }
        } else break;
      }
    }
  }
 
  /***************** Loopback *****************/
  if (uarts[i].regs.mcr & UART_MCR_LOOP) {
    debug(5, "uart_clock: Loopback\n");
    if ((uarts[i].regs.mcr & UART_MCR_AUX2) !=
        ((uarts[i].regs.msr & UART_MSR_DCD) >> 4))
      uarts[i].regs.msr |= UART_MSR_DDCD;
    if ((uarts[i].regs.mcr & UART_MCR_AUX1) <
        ((uarts[i].regs.msr & UART_MSR_RI) >> 4))
      uarts[i].regs.msr |= UART_MSR_TERI;
    if ((uarts[i].regs.mcr & UART_MCR_RTS) !=
        ((uarts[i].regs.msr & UART_MSR_CTS) >> 3))
      uarts[i].regs.msr |= UART_MSR_DCTS;
    if ((uarts[i].regs.mcr & UART_MCR_DTR) !=
        ((uarts[i].regs.msr & UART_MSR_DSR) >> 5))
      uarts[i].regs.msr |= UART_MSR_DDSR;
    uarts[i].regs.msr &= ~(UART_MSR_DCD | UART_MSR_RI
              | UART_MSR_DSR | UART_MSR_CTS);
    uarts[i].regs.msr |= ((uarts[i].regs.mcr & UART_MCR_AUX2) << 4);
    uarts[i].regs.msr |= ((uarts[i].regs.mcr & UART_MCR_AUX1) << 4);
    uarts[i].regs.msr |= ((uarts[i].regs.mcr & UART_MCR_RTS) << 3);
    uarts[i].regs.msr |= ((uarts[i].regs.mcr & UART_MCR_DTR) << 5);
  }
 
  if (uarts[i].regs.lsr & UART_LSR_RDRDY)
    uarts[i].istat.timeout_count++;
 
  /* Update LSR error bits from the ones from rx FIFO */
  if (uarts[i].istat.rxbuf_full) {
    uarts[i].regs.lsr |= uarts[i].regs.rxbuf[uarts[i].istat.rxbuf_tail] >> 8;
    /* we must delete the lsr status, so that we can clear it from lsr */
    uarts[i].regs.rxbuf[uarts[i].istat.rxbuf_tail] &= 0xff;
  }
 
  /* Interrupt detection in proper priority order. */
  uarts[i].regs.iir = UART_IIR_NO_INT;
  if (uarts[i].regs.ier & UART_IER_RLSI &&                    /* Receiver LS */
      uarts[i].regs.lsr & (UART_LSR_OVRRUN | UART_LSR_PARITY
        | UART_LSR_FRAME | UART_LSR_BREAK)) {
    uarts[i].regs.iir = UART_IIR_RLSI;
  } else if ((uarts[i].regs.ier & UART_IER_RDI)               /* RD available */
      && (uarts[i].istat.rxbuf_full >= UART_FIFO_TRIGGER(uarts[i].regs.fcr >> 6))
      && (uarts[i].regs.lsr & UART_LSR_RDRDY)) {
    uarts[i].regs.iir = UART_IIR_RDI;
  } else if ((uarts[i].regs.ier & UART_IER_RDI)               /* timeout */
      && (uarts[i].istat.timeout_count >= UART_CHAR_TIMEOUT * uarts[i].char_clks)
      && (uarts[i].istat.rxbuf_head != uarts[i].istat.rxbuf_tail)) {
    uarts[i].regs.iir = UART_IIR_CTI;
  } else if (uarts[i].regs.ier & UART_IER_THRI &&             /* Transm. empty */
      uarts[i].istat.thre_int == 1) {
    uarts[i].regs.iir = UART_IIR_THRI;
  } else if (uarts[i].regs.ier & UART_IER_MSI &&              /* Modem status */
      uarts[i].regs.msr & (UART_MSR_DCTS | UART_MSR_DDSR
        | UART_MSR_TERI | UART_MSR_DDCD)) {
    uarts[i].regs.iir = UART_IIR_MSI;
  }
  if (!(uarts[i].regs.iir & UART_IIR_NO_INT)) {
    debug (4, "uarts[i].regs.iir = %i\t", uarts[i].regs.iir);
    report_interrupt(config.uarts[i].irq);
  }
}
 
/* Reset.  It initializes all registers of all UART devices to zero values,
   (re)opens all RX/TX file streams and places devices in memory address
   space.  */
void uart_reset()
{
  int i;
  if (config.sim.verbose && config.nuarts) PRINTF("Resetting %u UART(s).\n", config.nuarts);
  memset(uarts, 0, sizeof(uarts));
 
  for(i = 0; i < config.nuarts; i++) {
    if (config.uarts[i].vapi_id) {
      if ((config.uarts[i].vapi_id & VAPI_DEVICE_ID) != i) {
        fprintf (stderr, "ERROR: Wrong vapi_id (0x%lx) for uart %i, last byte is required to be %02x; ignoring.\n", config.uarts[i].vapi_id, i, i);
        config.uarts[i].vapi_id = 0;
      } else {
        vapi_install_handler (config.uarts[i].vapi_id, uart_vapi_read);
        register_memoryarea(config.uarts[i].baseaddr, UART_ADDR_SPACE, 1, 0, uart_read_byte, uart_write_byte);
      }
    } else if (config.uarts[i].channel[0]) { /* MM: Try to create stream.  */
      if(channels[i])
        channel_close(channels[i]);
      else
        channels[i] = channel_init(config.uarts[i].channel);
      if(channel_open(channels[i]) < 0) {
        debug (0, "WARNING: UART%d has problems with channel \"%s\".\n", i, config.uarts[i].channel);
        continue;
      }
      if (config.sim.verbose)
        PRINTF("UART%d at 0x%.8lx uses ", i, config.uarts[i].baseaddr);
      register_memoryarea(config.uarts[i].baseaddr, UART_ADDR_SPACE, 1, 0, uart_read_byte, uart_write_byte);
    } else {
        debug (0, "WARNING: UART%d has no vapi nor channel specified\n", i);
        continue;
    }
 
    if (config.uarts[i].uart16550)
      uarts[i].fifo_len = 16;
    else
      uarts[i].fifo_len = 1;
 
    uarts[i].istat.rxbuf_head = uarts[i].istat.rxbuf_tail = 0;
    uarts[i].istat.txbuf_head = uarts[i].istat.txbuf_tail = 0;
 
    uarts[i].istat.break_set = 0;
    uarts[i].istat.timeout_count = 0;
 
    // For FIFO-mode only, THRE interrupt is set when both THR and FIFO are empty
    uarts[i].istat.thre_int = (uarts[i].fifo_len == 16);
 
    uarts[i].slowdown = UART_FGETC_SLOWDOWN;
 
    uarts[i].regs.lcr = UART_LCR_RESET;
    uarts[i].vapi.cur_break = uarts[i].vapi.cur_break_cnt = uarts[i].vapi.next_break = 0;
    uarts[i].vapi.next_break_cnt = -1;
    PRINTF ("%i\n", i);
    SCHED_ADD (uart_clock16, i, runtime.sim.cycles + UART_CLOCK_DIVIDER);
  }
}
 
/* Print register values on stdout. */
void uart_status()
{
  int i, j;
 
  for(i = 0; i < config.nuarts; i++) {
    if ( !config.uarts[i].baseaddr )
      continue;
    PRINTF("\nUART%d visible registers at 0x%.8lx:\n", i,
           config.uarts[i].baseaddr);
    PRINTF("RXBUF: ");
    for (j = uarts[i].istat.rxbuf_head; j != uarts[i].istat.rxbuf_tail; j = (j + 1) % uarts[i].fifo_len)
      PRINTF (" %.2x", uarts[i].regs.rxbuf[j]);
    PRINTF("TXBUF: ");
    for (j = uarts[i].istat.txbuf_head; j != uarts[i].istat.txbuf_tail; j = (j + 1) % uarts[i].fifo_len)
      PRINTF (" %.2x", uarts[i].regs.txbuf[j]);
    PRINTF("\n");
    PRINTF("DLL  : %.2x  DLH  : %.2x\n", uarts[i].regs.dll, uarts[i].regs.dlh);
    PRINTF("IER  : %.2x  IIR  : %.2x\n", uarts[i].regs.ier, uarts[i].regs.iir);
    PRINTF("LCR  : %.2x  MCR  : %.2x\n", uarts[i].regs.lcr, uarts[i].regs.mcr);
    PRINTF("LSR  : %.2x  MSR  : %.2x\n", uarts[i].regs.lsr, uarts[i].regs.msr);
    PRINTF("SCR  : %.2x\n", uarts[i].regs.scr);
 
    PRINTF("\nInternal registers (sim debug):\n");
    PRINTF("RXSER: %.2lx  TXSER: %.2lx\n", uarts[i].iregs.rxser,
           uarts[i].iregs.txser);
 
    PRINTF("\nInternal status (sim debug):\n");
    PRINTF("char_clks: %ld\n", uarts[i].char_clks);
    PRINTF("rxser_clks: %ld  txser_clks: %ld\n", uarts[i].istat.rxser_clks,
           uarts[i].istat.txser_clks);
    PRINTF("rxser: %d  txser: %d\n", uarts[i].istat.rxser_full, uarts[i].istat.txser_full);
    PRINTF("rxbuf_full: %d  txbuf_full: %d\n", uarts[i].istat.rxbuf_full, uarts[i].istat.txbuf_full);
    PRINTF("Using IRQ%i\n", config.uarts[i].irq);
    if (config.uarts[i].vapi_id)
      PRINTF ("Connected to vapi ID=%lx\n\n", config.uarts[i].vapi_id);
    /* TODO: replace by a channel_status
    else
      PRINTF("RX fs: %p  TX fs: %p\n\n", uarts[i].rxfs, uarts[i].txfs);
    */
  }
}

Line No.	Rev	Author	Line
1	31	lampret	`/* 16450.c -- Simulation of 8250/16450 serial UART`
2			`Copyright (C) 1999 Damjan Lampret, lampret@opencores.org`
3
4			`This file is part of OpenRISC 1000 Architectural Simulator.`
5
6			`This program is free software; you can redistribute it and/or modify`
7			`it under the terms of the GNU General Public License as published by`
8			`the Free Software Foundation; either version 2 of the License, or`
9			`(at your option) any later version.`
10
11			`This program is distributed in the hope that it will be useful,`
12			`but WITHOUT ANY WARRANTY; without even the implied warranty of`
13			`MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the`
14			`GNU General Public License for more details.`
15
16			`You should have received a copy of the GNU General Public License`
17			`along with this program; if not, write to the Free Software`
18			`Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */`
19
20			`/* This is functional simulation of 8250/16450 UARTs. Since we RX/TX data`
21			`via file streams, we can't simulate modem control lines coming from the`
22			`DCE and similar details of communication with the DCE.`
23
24			`This simulated UART device is intended for basic UART device driver`
25			`verification. From device driver perspective this device looks like a`
26			`regular UART but never reports and modem control lines changes (the`
27			`only DCE responses are incoming characters from the file stream).`
28			`*/`
29
30			`#include <stdlib.h>`
31			`#include <stdio.h>`
32			`#include <string.h>`
33
34	235	erez	`#include "abstract.h"`
35	31	lampret	`#include "16450.h"`
36			`#include "sim-config.h"`
37	102	lampret	`#include "pic.h"`
38	336	markom	`#include "vapi.h"`
39	805	markom	`#include "sched.h"`
40	1073	rprescott	`#include "channel.h"`
41	1308	phoenix	`#include "debug.h"`
42	31	lampret
43	409	markom	`#define MIN(a,b) ((a) < (b) ? (a) : (b))`
44
45	1073	rprescott	`static struct dev_16450 uarts[MAX_UARTS]; /* simulation info */`
46			`static struct channel * channels[MAX_UARTS] = { NULL, }; /* emulation info */`
47	31	lampret
48			`/* Number of clock cycles (one clock cycle is one call to the uart_clock())`
49			`before a single character is transmitted or received. */`
50	355	markom	`static unsigned long char_clks(int dll, int dlh, int lcr)`
51	31	lampret	`{`
52	409	markom	`float bauds_per_char = 1.;`
53	806	markom	`unsigned long char_clks = ((dlh << 8) + dll);`
54	355	markom
55			`if (lcr & UART_LCR_PARITY)`
56			`bauds_per_char = bauds_per_char + 1.;`
57	31	lampret
58	355	markom	`/* stop bits 1 or two */`
59			`if (lcr & UART_LCR_STOP)`
60			`bauds_per_char = bauds_per_char + 2.;`
61			`else`
62			`if ((lcr & 0x3) != 0)`
63			`bauds_per_char = bauds_per_char + 1.;`
64			`else`
65			`bauds_per_char = bauds_per_char + 1.5;`
66
67			`bauds_per_char = bauds_per_char + (5. + (lcr & 0x3));`
68
69			`return char_clks * bauds_per_char;`
70	31	lampret	`}`
71
72			`/* Set a specific UART register with value. */`
73	238	erez	`void uart_write_byte(unsigned long addr, unsigned long value)`
74	31	lampret	`{`
75	355	markom	`int chipsel;`
76
77			`debug(4, "uart_write_byte(%x,%02x)\n", addr, (unsigned)value);`
78	341	markom
79	424	markom	`for(chipsel = 0; chipsel < MAX_UARTS; chipsel++)`
80	355	markom	`if ((addr & ~(UART_ADDR_SPACE-1)) == config.uarts[chipsel].baseaddr)`
81			`break;`
82	424	markom	`if (chipsel >= MAX_UARTS) return;`
83	31	lampret
84	355	markom	`if (uarts[chipsel].regs.lcr & UART_LCR_DLAB) {`
85			`switch (addr % UART_ADDR_SPACE) {`
86			`case UART_DLL:`
87			`uarts[chipsel].regs.dll = value;`
88			`uarts[chipsel].char_clks = char_clks(uarts[chipsel].regs.dll, uarts[chipsel].regs.dlh, uarts[chipsel].regs.lcr);`
89			`return;`
90			`case UART_DLH:`
91			`uarts[chipsel].regs.dlh = value;`
92			`return;`
93			`}`
94			`}`
95
96			`switch (addr % UART_ADDR_SPACE) {`
97			`case UART_TXBUF:`
98			`if (uarts[chipsel].istat.txbuf_full < uarts[chipsel].fifo_len) {`
99			`uarts[chipsel].istat.txbuf_full++;`
100			`uarts[chipsel].regs.txbuf[uarts[chipsel].istat.txbuf_head] = value;`
101			`uarts[chipsel].istat.txbuf_head = (uarts[chipsel].istat.txbuf_head + 1) % uarts[chipsel].fifo_len;`
102			`} else`
103			`uarts[chipsel].regs.txbuf[uarts[chipsel].istat.txbuf_head] = value;`
104	341	markom
105	411	markom	`uarts[chipsel].regs.lsr &= ~(UART_LSR_TXSERE \| UART_LSR_TXBUFE);`
106	1153	sfurman	`if (uarts[chipsel].regs.iir & UART_IIR_THRI)`
107			`uarts[chipsel].istat.thre_int = 0;`
108	355	markom	`break;`
109	409	markom	`case UART_FCR:`
110			`uarts[chipsel].regs.fcr = value & UART_VALID_FCR;`
111			`if (uarts[chipsel].fifo_len == 1 && (value & UART_FCR_FIE)`
112			`\|\| uarts[chipsel].fifo_len != 1 && !(value & UART_FCR_FIE))`
113			`value \|= UART_FCR_RRXFI \| UART_FCR_RTXFI;`
114			`uarts[chipsel].fifo_len = (value & UART_FCR_FIE) ? 16 : 1;`
115			`if (value & UART_FCR_RTXFI) {`
116			`uarts[chipsel].istat.txbuf_head = uarts[chipsel].istat.txbuf_tail = 0;`
117			`uarts[chipsel].istat.txbuf_full = 0;`
118	1145	sfurman	`uarts[chipsel].regs.lsr \|= UART_LSR_TXBUFE;`
119
120			`// For FIFO-mode only, THRE interrupt is set when THR and FIFO are empty`
121			`uarts[chipsel].istat.thre_int = (uarts[chipsel].fifo_len == 16);`
122	409	markom	`}`
123			`if (value & UART_FCR_RRXFI) {`
124			`uarts[chipsel].istat.rxbuf_head = uarts[chipsel].istat.rxbuf_tail = 0;`
125			`uarts[chipsel].istat.rxbuf_full = 0;`
126	411	markom	`uarts[chipsel].regs.lsr &= ~UART_LSR_RDRDY;`
127	409	markom	`}`
128			`break;`
129	355	markom	`case UART_IER:`
130			`uarts[chipsel].regs.ier = value & UART_VALID_IER;`
131			`break;`
132			`case UART_LCR:`
133			`uarts[chipsel].regs.lcr = value & UART_VALID_LCR;`
134	409	markom	`uarts[chipsel].char_clks = char_clks(uarts[chipsel].regs.dll, uarts[chipsel].regs.dlh, uarts[chipsel].regs.lcr);`
135	355	markom	`break;`
136			`case UART_MCR:`
137			`uarts[chipsel].regs.mcr = value & UART_VALID_MCR;`
138			`break;`
139			`case UART_SCR:`
140			`uarts[chipsel].regs.scr = value;`
141			`break;`
142			`default:`
143			`debug(1, "write out of range (addr %x)\n", addr);`
144			`}`
145	31	lampret	`}`
146
147			`/* Read a specific UART register. */`
148	238	erez	`unsigned long uart_read_byte(unsigned long addr)`
149	31	lampret	`{`
150	355	markom	`unsigned char value = 0;`
151			`int chipsel;`
152
153			`debug(4, "uart_read_byte(%x)", addr);`
154
155	424	markom	`for(chipsel = 0; chipsel < MAX_UARTS; chipsel++)`
156	355	markom	`if ((addr & ~(UART_ADDR_SPACE-1)) == config.uarts[chipsel].baseaddr)`
157			`break;`
158	31	lampret
159	424	markom	`if (chipsel >= MAX_UARTS)`
160	355	markom	`return 0;`
161	344	markom
162	355	markom	`if (uarts[chipsel].regs.lcr & UART_LCR_DLAB) {`
163			`switch (addr % UART_ADDR_SPACE) {`
164			`case UART_DLL:`
165			`value = uarts[chipsel].regs.dll;`
166			`debug(4, "= %x\n", value);`
167			`return value;`
168			`case UART_DLH:`
169			`value = uarts[chipsel].regs.dlh;`
170			`debug(4, "= %x\n", value);`
171			`return value;`
172			`}`
173			`}`
174
175			`switch (addr % UART_ADDR_SPACE) {`
176			`case UART_RXBUF:`
177	409	markom	`{ /* Print out FIFO for debugging */`
178			`int i;`
179			`debug(4, "(%i/%i,%i,%i:", uarts[chipsel].istat.rxbuf_full, uarts[chipsel].fifo_len,`
180			`uarts[chipsel].istat.rxbuf_head, uarts[chipsel].istat.rxbuf_tail);`
181			`for (i = 0; i < uarts[chipsel].istat.rxbuf_full; i++)`
182			`debug(4, "%02x ", uarts[chipsel].regs.rxbuf[(uarts[chipsel].istat.rxbuf_tail + i) % uarts[chipsel].fifo_len]);`
183			`debug(4, ")");`
184			`}`
185	355	markom	`if (uarts[chipsel].istat.rxbuf_full) {`
186			`value = uarts[chipsel].regs.rxbuf[uarts[chipsel].istat.rxbuf_tail];`
187			`uarts[chipsel].istat.rxbuf_tail = (uarts[chipsel].istat.rxbuf_tail + 1) % uarts[chipsel].fifo_len;`
188			`uarts[chipsel].istat.rxbuf_full--;`
189			`}`
190
191			`if (uarts[chipsel].istat.rxbuf_full)`
192			`uarts[chipsel].regs.lsr \|= UART_LSR_RDRDY;`
193			`else`
194			`uarts[chipsel].regs.lsr &= ~UART_LSR_RDRDY;`
195	409	markom
196			`uarts[chipsel].istat.timeout_count = 0;`
197	355	markom	`break;`
198			`case UART_IER:`
199			`value = uarts[chipsel].regs.ier & UART_VALID_IER;`
200			`break;`
201			`case UART_IIR:`
202			`value = (uarts[chipsel].regs.iir & UART_VALID_IIR) \| 0xc0;`
203	1153	sfurman	`if (uarts[chipsel].regs.iir & UART_IIR_THRI)`
204	490	markom	`uarts[chipsel].istat.thre_int = 0;`
205	355	markom	`break;`
206			`case UART_LCR:`
207			`value = uarts[chipsel].regs.lcr & UART_VALID_LCR;`
208			`break;`
209			`case UART_MCR:`
210			`value = 0;`
211			`break;`
212			`case UART_LSR:`
213			`value = uarts[chipsel].regs.lsr & UART_VALID_LSR;`
214			`uarts[chipsel].regs.lsr &=`
215	409	markom	`~(UART_LSR_OVRRUN \| UART_LSR_BREAK \| UART_LSR_PARITY`
216			`\| UART_LSR_FRAME \| UART_LSR_RXERR);`
217	355	markom	`break;`
218			`case UART_MSR:`
219			`value = uarts[chipsel].regs.msr & UART_VALID_MSR;`
220			`uarts[chipsel].regs.msr = 0;`
221			`break;`
222			`case UART_SCR:`
223			`value = uarts[chipsel].regs.scr;`
224			`break;`
225			`default:`
226			`debug(1, "read out of range (addr %x)\n", addr);`
227			`}`
228			`debug(4, " = %x\n", value);`
229			`return value;`
230	31	lampret	`}`
231
232	336	markom	`/* Function that handles incoming VAPI data. */`
233			`void uart_vapi_read (unsigned long id, unsigned long data)`
234			`{`
235	341	markom	`int uart;`
236	344	markom	`debug(4, "UART: id %08x, data %08x\n", id, data);`
237	341	markom	`uart = id & VAPI_DEVICE_ID;`
238			`uarts[uart].vapi_buf[uarts[uart].vapi_buf_head_ptr] = data;`
239	409	markom	`uarts[uart].vapi_buf_head_ptr = (uarts[uart].vapi_buf_head_ptr + 1) % UART_VAPI_BUF_LEN;`
240	341	markom	`if (uarts[uart].vapi_buf_tail_ptr == uarts[uart].vapi_buf_head_ptr) {`
241			`fprintf (stderr, "FATAL: uart VAPI buffer to small.\n");`
242			`exit (1);`
243			`}`
244			`}`
245	336	markom
246	409	markom	`static void send_char (int uart, int bits_send)`
247			`{`
248	1244	hpanther	`PRINTF ("%c", uarts[uart].iregs.txser);`
249	409	markom	`debug(4, "TX \'%c\' via UART%d...\n", uarts[uart].iregs.txser, uart);`
250			`if (uarts[uart].regs.mcr & UART_MCR_LOOP)`
251			`uarts[uart].iregs.loopback = uarts[uart].iregs.txser;`
252			`else {`
253			`/* Send to either VAPI or to file */`
254			`if (config.uarts[uart].vapi_id) {`
255			`int par, pe, fe, nbits;`
256			`int j, data;`
257			`unsigned long packet = 0;`
258
259			`nbits = MIN (bits_send, (uarts[uart].regs.lcr & UART_LCR_WLEN8) + 5);`
260			`/* Encode a packet */`
261			`packet = uarts[uart].iregs.txser & ((1 << nbits) - 1);`
262
263			`/* Calculate parity */`
264			`for (j = 0, par = 0; j < nbits; j++)`
265			`par ^= (packet >> j) & 1;`
266
267			`if (uarts[uart].regs.lcr & UART_LCR_PARITY) {`
268			`if (uarts[uart].regs.lcr & UART_LCR_SPAR) {`
269			`packet \|= 1 << nbits;`
270			`} else {`
271			`if (uarts[uart].regs.lcr & UART_LCR_EPAR)`
272			`packet \|= par << nbits;`
273			`else`
274			`packet \|= (par ^ 1) << nbits;`
275			`}`
276			`nbits++;`
277			`}`
278			`packet \|= 1 << (nbits++);`
279			`if (uarts[uart].regs.lcr & UART_LCR_STOP)`
280			`packet \|= 1 << (nbits++);`
281
282			`/* Decode a packet */`
283			`nbits = (uarts[uart].vapi.lcr & UART_LCR_WLEN8) + 5;`
284			`data = packet & ((1 << nbits) - 1);`
285
286			`/* Calculate parity, including parity bit */`
287			`for (j = 0, par = 0; j < nbits + 1; j++)`
288			`par ^= (packet >> j) & 1;`
289
290			`if (uarts[uart].vapi.lcr & UART_LCR_PARITY) {`
291			`if (uarts[uart].vapi.lcr & UART_LCR_SPAR) {`
292			`pe = !((packet >> nbits) & 1);`
293			`} else {`
294			`if (uarts[uart].vapi.lcr & UART_LCR_EPAR)`
295			`pe = par != 0;`
296			`else`
297			`pe = par != 1;`
298			`}`
299			`nbits++;`
300			`} else`
301			`pe = 0;`
302
303			`fe = ((packet >> (nbits++)) & 1) ^ 1;`
304			`if (uarts[uart].vapi.lcr & UART_LCR_STOP)`
305			`fe \|= ((packet >> (nbits++)) & 1) ^ 1;`
306
307			`debug (4, "lcr vapi %02x, uart %02x\n", uarts[uart].vapi.lcr, uarts[uart].regs.lcr);`
308			`data \|= (uarts[uart].vapi.lcr << 8) \| (pe << 16) \| (fe << 17) \| (uarts[uart].vapi.lcr << 8);`
309	1308	phoenix	`PRINTF ("vapi_send (%08lx, %08x)\n", config.uarts[uart].vapi_id, data);`
310	409	markom	`debug (4, "vapi_send (%08x, %08x)\n", config.uarts[uart].vapi_id, data);`
311			`vapi_send (config.uarts[uart].vapi_id, data);`
312			`} else {`
313	1073	rprescott	`char buffer[1] = { uarts[uart].iregs.txser & 0xFF };`
314			`channel_write(channels[uart], buffer, 1);`
315	409	markom	`}`
316			`}`
317			`uarts[uart].istat.txser_full = 0;`
318			`uarts[uart].istat.txser_clks = 0;`
319			`}`
320
321	411	markom	`/* Adds a character to the FIFO */`
322
323			`void uart_add_char (int uart, int ch)`
324			`{`
325			`if (uarts[uart].istat.rxbuf_full + 1 > uarts[uart].fifo_len)`
326			`uarts[uart].regs.lsr \|= UART_LSR_OVRRUN \| UART_LSR_RXERR;`
327			`else {`
328			`debug(4, "add %02x\n", ch);`
329			`uarts[uart].regs.rxbuf[uarts[uart].istat.rxbuf_head] = ch;`
330			`uarts[uart].istat.rxbuf_head = (uarts[uart].istat.rxbuf_head + 1) % uarts[uart].fifo_len;`
331			`uarts[uart].istat.rxbuf_full++;`
332			`}`
333			`uarts[uart].regs.lsr \|= UART_LSR_RDRDY;`
334			`uarts[uart].istat.timeout_count = 0;`
335			`}`
336
337	806	markom	`/* Simulation hook. Must be called every clock cycle to simulate all UART`
338			`devices. It does internal functional UART simulation. */`
339	821	markom	`void uart_clock16 (int i)`
340	806	markom	`{`
341			`int retval;`
342	1073	rprescott
343	821	markom	`/* Schedule for later */`
344	884	markom	`SCHED_ADD (uart_clock16, i, runtime.sim.cycles + UART_CLOCK_DIVIDER);`
345	821	markom
346	806	markom	`/* If VAPI is not selected, UART communicates with two file streams;`
347			`if VAPI is selected, we use VAPI streams. */`
348			`/* if txfs is corrupted, skip this uart. */`
349	1073	rprescott	`if (!config.uarts[i].vapi_id && !channel_ok(channels[i])) return;`
350	806	markom
351			`if (uarts[i].vapi.next_break_cnt >= 0)`
352			`if (--uarts[i].vapi.next_break_cnt < 0) {`
353			`if (!(uarts[i].vapi.cur_break = uarts[i].vapi.next_break))`
354			`uarts[i].istat.break_set = 0;`
355			`}`
356	821	markom
357	806	markom	`/*************** Transmit ***************/`
358			`if (!uarts[i].istat.txser_full) {`
359			`// uarts[i].regs.lsr \|= UART_LSR_TXBUFE;`
360			`if (uarts[i].istat.txbuf_full) {`
361			`uarts[i].iregs.txser = uarts[i].regs.txbuf[uarts[i].istat.txbuf_tail];`
362			`uarts[i].istat.txbuf_tail = (uarts[i].istat.txbuf_tail + 1) % uarts[i].fifo_len;`
363			`uarts[i].istat.txser_full = 1;`
364			`uarts[i].istat.txbuf_full--;`
365			`uarts[i].regs.lsr &= ~UART_LSR_TXSERE;`
366	1143	sfurman
367			`// When UART is in either character mode, i.e. 16450 emulation mode, or FIFO mode,`
368			`// the THRE interrupt is raised when THR transitions from full to empty.`
369			`if (!uarts[i].istat.txbuf_full) {`
370			`uarts[i].istat.thre_int = 1;`
371			`uarts[i].regs.lsr \|= UART_LSR_TXBUFE;`
372			`}`
373	806	markom	`} else {`
374			`uarts[i].regs.lsr \|= UART_LSR_TXSERE;`
375			`}`
376			`} else if (uarts[i].char_clks <= uarts[i].istat.txser_clks++) {`
377			`send_char(i, (uarts[i].regs.lcr & UART_LCR_WLEN8) + 5); /* We've sent all bits */`
378			`} else {`
379			`/* We are still sending char here*/`
380
381			`/* Check if we set the break bit */`
382			`if (uarts[i].regs.lcr & UART_LCR_SBC) {`
383			`if (!uarts[i].vapi.break_sent) {`
384			`#if 0`
385			`/* Send broken frame */`
386			`int nbits_sent = ((uarts[i].regs.lcr & UART_LCR_WLEN8) + 5) * (uarts[i].istat.txser_clks - 1) / uarts[i].char_clks;`
387			`send_char(i, nbits_sent);`
388			`#endif`
389			`/* Send one break signal */`
390			`vapi_send (config.uarts[i].vapi_id, UART_LCR_SBC << 8);`
391			`uarts[i].vapi.break_sent = 1;`
392			`}`
393			`/* mark as character was sent */`
394			`uarts[i].istat.txser_full = 0;`
395			`uarts[i].istat.txser_clks = 0;`
396			`} else`
397			`uarts[i].vapi.break_sent = 0;`
398	1143	sfurman
399	806	markom	`}`
400	1143	sfurman
401	806	markom	`/*************** Receive ***************/`
402
403			`/* Is there a break? */`
404			`if (uarts[i].vapi.cur_break) {`
405			`uarts[i].vapi.cur_break_cnt++;`
406			`if (uarts[i].vapi.cur_break_cnt > UART_BREAK_COUNT * uarts[i].vapi.char_clks) {`
407			`if (!uarts[i].istat.break_set) {`
408			`unsigned lsr;`
409			`uarts[i].istat.break_set = 1;`
410			`lsr = UART_LSR_BREAK \| UART_LSR_RXERR \| UART_LSR_RDRDY;`
411	997	markom	`PRINTF ("[%x]\n", uarts[i].regs.lsr);`
412	806	markom	`uarts[i].istat.rxser_full = 0;`
413			`uarts[i].istat.rxser_clks = 0;`
414			`uart_add_char (i, lsr << 8);`
415			`} else`
416			`uarts[i].vapi.cur_break_cnt = 0;`
417			`}`
418			`if (uarts[i].istat.rxser_full) {`
419			`uarts[i].istat.rxser_full = 0;`
420			`uarts[i].istat.rxser_clks = 0;`
421			`}`
422			`} else {`
423			`if (uarts[i].istat.rxser_full) {`
424			`if (uarts[i].char_clks <= uarts[i].istat.rxser_clks++) {`
425			`/* Set unused character bits to zero and allow lsr register in fifo */`
426			`uarts[i].iregs.rxser &= ((1 << ((uarts[i].regs.lcr & 3) + 5)) - 1) \| 0xff00;`
427	1308	phoenix	`debug(4, "Receiving 0x%02x'%c' via UART%d...\n", uarts[i].iregs.rxser,`
428			`uarts[i].iregs.rxser, i);`
429			`PRINTF ("%c", uarts[i].iregs.rxser);`
430	806	markom	`uarts[i].istat.rxser_full = 0;`
431			`uarts[i].istat.rxser_clks = 0;`
432			`uart_add_char (i, uarts[i].iregs.rxser);`
433			`}`
434			`}`
435			`}`
436
437			`/* Check if there is something waiting, and put it into rxser */`
438			`if (uarts[i].regs.mcr & UART_MCR_LOOP) {`
439			`uarts[i].iregs.rxser = uarts[i].iregs.loopback;`
440			`uarts[i].istat.rxser_full = 1;`
441			`} else {`
442			`if (!config.uarts[i].vapi_id) {`
443			`if(uarts[i].istat.rxser_full == 0) {`
444			`if (uarts[i].slowdown)`
445			`uarts[i].slowdown--;`
446	1073	rprescott	`else {`
447			`char buffer[1];`
448			`retval = channel_read(channels[i], buffer, 1);`
449			`if(retval < 0)`
450			`perror(config.uarts[i].channel);`
451			`else if(retval > 0) {`
452	1116	sfurman	`uarts[i].iregs.rxser = (unsigned char)buffer[0];`
453	1073	rprescott	`uarts[i].istat.rxser_full = 1;`
454			`} else`
455			`uarts[i].slowdown = UART_FGETC_SLOWDOWN;`
456			`}`
457	806	markom	`}`
458			`} else { /* VAPI */`
459			`int received = 0;`
460			`/* do not handle commands while receiving */`
461			`if (uarts[i].istat.rxser_full) return;`
462			`while (!received) {`
463			`if (uarts[i].vapi_buf_head_ptr != uarts[i].vapi_buf_tail_ptr) {`
464			`unsigned long data = uarts[i].vapi_buf[uarts[i].vapi_buf_tail_ptr];`
465			`debug(4, "Handling: %08x (%i,%i)\n", data, uarts[i].vapi_buf_head_ptr, uarts[i].vapi_buf_tail_ptr);`
466			`uarts[i].vapi_buf_tail_ptr = (uarts[i].vapi_buf_tail_ptr + 1) % UART_VAPI_BUF_LEN;`
467			`switch (data >> 24) {`
468			`case 0x00:`
469			`uarts[i].vapi.lcr = (data >> 8) & 0xff;`
470			`/* Put data into rx fifo */`
471			`uarts[i].iregs.rxser = data & 0xff;`
472			`uarts[i].vapi.char_clks = char_clks (uarts[i].vapi.dll, uarts[i].vapi.dlh, uarts[i].vapi.lcr);`
473			`if ((uarts[i].vapi.lcr & ~UART_LCR_SBC) != (uarts[i].regs.lcr & ~UART_LCR_SBC)`
474			`\|\| uarts[i].vapi.char_clks != uarts[i].char_clks`
475			`\|\| uarts[i].vapi.skew < -MAX_SKEW \|\| uarts[i].vapi.skew > MAX_SKEW) {`
476			`debug (3, "WARNING: unmatched VAPI (%02x) and uart (%02x) modes.\n",`
477			`uarts[i].vapi.lcr & ~UART_LCR_SBC, uarts[i].regs.lcr & ~UART_LCR_SBC);`
478			`/* Set error bits */`
479			`uarts[i].iregs.rxser \|= (UART_LSR_FRAME \| UART_LSR_RXERR) << 8;`
480			`if (uarts[i].regs.lcr & UART_LCR_PARITY) uarts[i].iregs.rxser \|= UART_LSR_PARITY << 8;`
481			`}`
482			`uarts[i].istat.rxser_full = 1;`
483			`received = 1;`
484			`break;`
485			`case 0x01:`
486			`uarts[i].vapi.dll = (data >> 0) & 0xff;`
487			`uarts[i].vapi.dlh = (data >> 8) & 0xff;`
488			`break;`
489			`case 0x02:`
490			`uarts[i].vapi.lcr = (data >> 8) & 0xff;`
491			`break;`
492			`case 0x03:`
493			`uarts[i].vapi.skew = (signed short)(data & 0xffff);`
494			`break;`
495			`case 0x04:`
496			`uarts[i].vapi.next_break_cnt = data & 0xffff;`
497			`uarts[i].vapi.next_break = (data >> 16) & 1;`
498			`break;`
499			`default:`
500			`debug (0, "WARNING: Invalid vapi command %02x\n", data >> 24);`

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