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/* Remote target communications for serial-line targets using SDS' protocol.

   Copyright 1997, 1998, 1999, 2000, 2001, 2002 Free Software

   Foundation, Inc.

   This file is part of GDB.

   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., 59 Temple Place - Suite 330,

   Boston, MA 02111-1307, USA.  */

/* This interface was written by studying the behavior of the SDS

   monitor on an ADS 821/860 board, and by consulting the

   documentation of the monitor that is available on Motorola's web

   site.  -sts 8/13/97 */

#include "defs.h"

#include "gdb_string.h"

#include <fcntl.h>

#include "frame.h"

#include "inferior.h"

#include "bfd.h"

#include "symfile.h"

#include "target.h"

#include "gdbcmd.h"

#include "objfiles.h"

#include "gdb-stabs.h"

#include "gdbthread.h"

#include "gdbcore.h"

#include "regcache.h"

#ifdef USG

#include <sys/types.h>

#endif

#include <signal.h>

#include "serial.h"

extern void _initialize_remote_sds (void);

/* Declarations of local functions. */

static int sds_write_bytes (CORE_ADDR, char *, int);

static int sds_read_bytes (CORE_ADDR, char *, int);

static void sds_files_info (struct target_ops *ignore);

static int sds_xfer_memory (CORE_ADDR, char *, int, int,

                            struct mem_attrib *, struct target_ops *);

static void sds_prepare_to_store (void);

static void sds_fetch_registers (int);

static void sds_resume (ptid_t, int, enum target_signal);

static int sds_start_remote (PTR);

static void sds_open (char *, int);

static void sds_close (int);

static void sds_store_registers (int);

static void sds_mourn (void);

static void sds_create_inferior (char *, char *, char **);

static void sds_load (char *, int);

static int getmessage (unsigned char *, int);

static int putmessage (unsigned char *, int);

static int sds_send (unsigned char *, int);

static int readchar (int);

static ptid_t sds_wait (ptid_t, struct target_waitstatus *);

static void sds_kill (void);

static int tohex (int);

static int fromhex (int);

static void sds_detach (char *, int);

static void sds_interrupt (int);

static void sds_interrupt_twice (int);

static void interrupt_query (void);

static int read_frame (char *);

static int sds_insert_breakpoint (CORE_ADDR, char *);

static int sds_remove_breakpoint (CORE_ADDR, char *);

static void init_sds_ops (void);

static void sds_command (char *args, int from_tty);

/* Define the target operations vector. */

static struct target_ops sds_ops;

/* This was 5 seconds, which is a long time to sit and wait.

   Unless this is going though some terminal server or multiplexer or

   other form of hairy serial connection, I would think 2 seconds would

   be plenty.  */

static int sds_timeout = 2;

/* Descriptor for I/O to remote machine.  Initialize it to NULL so

   that sds_open knows that we don't have a file open when the program

   starts.  */

static struct serial *sds_desc = NULL;

/* This limit comes from the monitor.  */

#define PBUFSIZ 250

/* Maximum number of bytes to read/write at once.  The value here

   is chosen to fill up a packet (the headers account for the 32).  */

#define MAXBUFBYTES ((PBUFSIZ-32)/2)

static int next_msg_id;

static int just_started;

static int message_pending;

/* Clean up connection to a remote debugger.  */

/* ARGSUSED */

static void

sds_close (int quitting)

{

  if (sds_desc)

    serial_close (sds_desc);

  sds_desc = NULL;

}

/* Stub for catch_errors.  */

static int

sds_start_remote (PTR dummy)

{

  int c;

  unsigned char buf[200];

  immediate_quit++;             /* Allow user to interrupt it */

  /* Ack any packet which the remote side has already sent.  */

  serial_write (sds_desc, "{#*\r\n", 5);

  serial_write (sds_desc, "{#}\r\n", 5);

  while ((c = readchar (1)) >= 0)

    printf_unfiltered ("%c", c);

  printf_unfiltered ("\n");

  next_msg_id = 251;

  buf[0] = 26;

  sds_send (buf, 1);

  buf[0] = 0;

  sds_send (buf, 1);

  immediate_quit--;

  start_remote ();              /* Initialize gdb process mechanisms */

  return 1;

}

/* Open a connection to a remote debugger.

   NAME is the filename used for communication.  */

static void

sds_open (char *name, int from_tty)

{

  if (name == 0)

    error ("To open a remote debug connection, you need to specify what serial\n\

device is attached to the remote system (e.g. /dev/ttya).");

  target_preopen (from_tty);

  unpush_target (&sds_ops);

  sds_desc = serial_open (name);

  if (!sds_desc)

    perror_with_name (name);

  if (baud_rate != -1)

    {

      if (serial_setbaudrate (sds_desc, baud_rate))

        {

          serial_close (sds_desc);

          perror_with_name (name);

        }

    }

  serial_raw (sds_desc);

  /* If there is something sitting in the buffer we might take it as a

     response to a command, which would be bad.  */

  serial_flush_input (sds_desc);

  if (from_tty)

    {

      puts_filtered ("Remote debugging using ");

      puts_filtered (name);

      puts_filtered ("\n");

    }

  push_target (&sds_ops);       /* Switch to using remote target now */

  just_started = 1;

  /* Start the remote connection; if error (0), discard this target.

     In particular, if the user quits, be sure to discard it (we'd be

     in an inconsistent state otherwise).  */

  if (!catch_errors (sds_start_remote, NULL,

                     "Couldn't establish connection to remote target\n",

                     RETURN_MASK_ALL))

    pop_target ();

}

/* This takes a program previously attached to and detaches it.  After

   this is done, GDB can be used to debug some other program.  We

   better not have left any breakpoints in the target program or it'll

   die when it hits one.  */

static void

sds_detach (char *args, int from_tty)

{

  char buf[PBUFSIZ];

  if (args)

    error ("Argument given to \"detach\" when remotely debugging.");

#if 0

  /* Tell the remote target to detach.  */

  strcpy (buf, "D");

  sds_send (buf, 1);

#endif

  pop_target ();

  if (from_tty)

    puts_filtered ("Ending remote debugging.\n");

}

/* Convert hex digit A to a number.  */

static int

fromhex (int a)

{

  if (a >= '0' && a <= '9')

    return a - '0';

  else if (a >= 'a' && a <= 'f')

    return a - 'a' + 10;

  else

    error ("Reply contains invalid hex digit %d", a);

}

/* Convert number NIB to a hex digit.  */

static int

tohex (int nib)

{

  if (nib < 10)

    return '0' + nib;

  else

    return 'a' + nib - 10;

}

static int

tob64 (unsigned char *inbuf, char *outbuf, int len)

{

  int i, sum;

  char *p;

  if (len % 3 != 0)

    error ("bad length");

  p = outbuf;

  for (i = 0; i < len; i += 3)

    {

      /* Collect the next three bytes into a number.  */

      sum = ((long) *inbuf++) << 16;

      sum |= ((long) *inbuf++) << 8;

      sum |= ((long) *inbuf++);

      /* Spit out 4 6-bit encodings.  */

      *p++ = ((sum >> 18) & 0x3f) + '0';

      *p++ = ((sum >> 12) & 0x3f) + '0';

      *p++ = ((sum >> 6) & 0x3f) + '0';

      *p++ = (sum & 0x3f) + '0';

    }

  return (p - outbuf);

}

static int

fromb64 (char *inbuf, char *outbuf, int len)

{

  int i, sum;

  if (len % 4 != 0)

    error ("bad length");

  for (i = 0; i < len; i += 4)

    {

      /* Collect 4 6-bit digits.  */

      sum = (*inbuf++ - '0') << 18;

      sum |= (*inbuf++ - '0') << 12;

      sum |= (*inbuf++ - '0') << 6;

      sum |= (*inbuf++ - '0');

      /* Now take the resulting 24-bit number and get three bytes out

         of it.  */

      *outbuf++ = (sum >> 16) & 0xff;

      *outbuf++ = (sum >> 8) & 0xff;

      *outbuf++ = sum & 0xff;

    }

  return (len / 4) * 3;

}

/* Tell the remote machine to resume.  */

static enum target_signal last_sent_signal = TARGET_SIGNAL_0;

int last_sent_step;

static void

sds_resume (ptid_t ptid, int step, enum target_signal siggnal)

{

  unsigned char buf[PBUFSIZ];

  last_sent_signal = siggnal;

  last_sent_step = step;

  buf[0] = (step ? 21 : 20);

  buf[1] = 0;                    /* (should be signal?) */

  sds_send (buf, 2);

}

/* Send a message to target to halt it.  Target will respond, and send

   us a message pending notice.  */

static void

sds_interrupt (int signo)

{

  unsigned char buf[PBUFSIZ];

  /* If this doesn't work, try more severe steps.  */

  signal (signo, sds_interrupt_twice);

  if (remote_debug)

    fprintf_unfiltered (gdb_stdlog, "sds_interrupt called\n");

  buf[0] = 25;

  sds_send (buf, 1);

}

static void (*ofunc) ();

/* The user typed ^C twice.  */

static void

sds_interrupt_twice (int signo)

{

  signal (signo, ofunc);

  interrupt_query ();

  signal (signo, sds_interrupt);

}

/* Ask the user what to do when an interrupt is received.  */

static void

interrupt_query (void)

{

  target_terminal_ours ();

  if (query ("Interrupted while waiting for the program.\n\

Give up (and stop debugging it)? "))

    {

      target_mourn_inferior ();

      throw_exception (RETURN_QUIT);

    }

  target_terminal_inferior ();

}

/* If nonzero, ignore the next kill.  */

int kill_kludge;

/* Wait until the remote machine stops, then return, storing status in

   STATUS just as `wait' would.  Returns "pid" (though it's not clear

   what, if anything, that means in the case of this target).  */

static ptid_t

sds_wait (ptid_t ptid, struct target_waitstatus *status)

{

  unsigned char buf[PBUFSIZ];

  int retlen;

  status->kind = TARGET_WAITKIND_EXITED;

  status->value.integer = 0;

  ofunc = (void (*)()) signal (SIGINT, sds_interrupt);

  signal (SIGINT, ofunc);

  if (just_started)

    {

      just_started = 0;

      status->kind = TARGET_WAITKIND_STOPPED;

      return inferior_ptid;

    }

  while (1)

    {

      getmessage (buf, 1);

      if (message_pending)

        {

          buf[0] = 26;

          retlen = sds_send (buf, 1);

          if (remote_debug)

            {

              fprintf_unfiltered (gdb_stdlog, "Signals: %02x%02x %02x %02x\n",

                                  buf[0], buf[1],

                                  buf[2], buf[3]);

            }

          message_pending = 0;

          status->kind = TARGET_WAITKIND_STOPPED;

          status->value.sig = TARGET_SIGNAL_TRAP;

          goto got_status;

        }

    }

got_status:

  return inferior_ptid;

}

static unsigned char sprs[16];

/* Read the remote registers into the block REGS.  */

/* Currently we just read all the registers, so we don't use regno.  */

/* ARGSUSED */

static void

sds_fetch_registers (int regno)

{

  unsigned char buf[PBUFSIZ];

  int i, retlen;

  char regs[REGISTER_BYTES];

  /* Unimplemented registers read as all bits zero.  */

  memset (regs, 0, REGISTER_BYTES);

  buf[0] = 18;

  buf[1] = 1;

  buf[2] = 0;

  retlen = sds_send (buf, 3);

  for (i = 0; i < 4 * 6; ++i)

    regs[i + 4 * 32 + 8 * 32] = buf[i];

  for (i = 0; i < 4 * 4; ++i)

    sprs[i] = buf[i + 4 * 7];

  buf[0] = 18;

  buf[1] = 2;

  buf[2] = 0;

  retlen = sds_send (buf, 3);

  for (i = 0; i < retlen; i++)

    regs[i] = buf[i];

  /* (should warn about reply too short) */

  for (i = 0; i < NUM_REGS; i++)

    supply_register (i, &regs[REGISTER_BYTE (i)]);

}

/* Prepare to store registers.  Since we may send them all, we have to

   read out the ones we don't want to change first.  */

static void

sds_prepare_to_store (void)

{

  /* Make sure the entire registers array is valid.  */

  read_register_bytes (0, (char *) NULL, REGISTER_BYTES);

}

/* Store register REGNO, or all registers if REGNO == -1, from the contents

   of REGISTERS.  FIXME: ignores errors.  */

static void

sds_store_registers (int regno)

{

  unsigned char *p, buf[PBUFSIZ];

  int i;

  /* Store all the special-purpose registers.  */

  p = buf;

  *p++ = 19;

  *p++ = 1;

  *p++ = 0;

  *p++ = 0;

  for (i = 0; i < 4 * 6; i++)

    *p++ = registers[i + 4 * 32 + 8 * 32];

  for (i = 0; i < 4 * 1; i++)

    *p++ = 0;

  for (i = 0; i < 4 * 4; i++)

    *p++ = sprs[i];

  sds_send (buf, p - buf);

  /* Store all the general-purpose registers.  */

  p = buf;

  *p++ = 19;

  *p++ = 2;

  *p++ = 0;

  *p++ = 0;

  for (i = 0; i < 4 * 32; i++)

    *p++ = registers[i];

  sds_send (buf, p - buf);

}

/* Write memory data directly to the remote machine.  This does not

   inform the data cache; the data cache uses this.  MEMADDR is the

   address in the remote memory space.  MYADDR is the address of the

   buffer in our space.  LEN is the number of bytes.

   Returns number of bytes transferred, or 0 for error.  */

static int

sds_write_bytes (CORE_ADDR memaddr, char *myaddr, int len)

{

  int max_buf_size;             /* Max size of packet output buffer */

  int origlen;

  unsigned char buf[PBUFSIZ];

  int todo;

  int i;

  /* Chop the transfer down if necessary */

  max_buf_size = 150;

  origlen = len;

  while (len > 0)

    {

      todo = min (len, max_buf_size);

      buf[0] = 13;

      buf[1] = 0;

      buf[2] = (int) (memaddr >> 24) & 0xff;

      buf[3] = (int) (memaddr >> 16) & 0xff;

      buf[4] = (int) (memaddr >> 8) & 0xff;

      buf[5] = (int) (memaddr) & 0xff;

      buf[6] = 1;

      buf[7] = 0;

      for (i = 0; i < todo; i++)

        buf[i + 8] = myaddr[i];

      sds_send (buf, 8 + todo);

      /* (should look at result) */

      myaddr += todo;

      memaddr += todo;

      len -= todo;

    }

  return origlen;

}

/* Read memory data directly from the remote machine.  This does not

   use the data cache; the data cache uses this.  MEMADDR is the

   address in the remote memory space.  MYADDR is the address of the

   buffer in our space.  LEN is the number of bytes.

   Returns number of bytes transferred, or 0 for error.  */

static int

sds_read_bytes (CORE_ADDR memaddr, char *myaddr, int len)

{

  int max_buf_size;             /* Max size of packet output buffer */

  int origlen, retlen;

  unsigned char buf[PBUFSIZ];

  int todo;

  int i;

  /* Chop the transfer down if necessary */

  max_buf_size = 150;

  origlen = len;

  while (len > 0)

    {

      todo = min (len, max_buf_size);

      buf[0] = 12;

      buf[1] = 0;

      buf[2] = (int) (memaddr >> 24) & 0xff;

      buf[3] = (int) (memaddr >> 16) & 0xff;

      buf[4] = (int) (memaddr >> 8) & 0xff;

      buf[5] = (int) (memaddr) & 0xff;

      buf[6] = (int) (todo >> 8) & 0xff;

      buf[7] = (int) (todo) & 0xff;

      buf[8] = 1;

      retlen = sds_send (buf, 9);

      if (retlen - 2 != todo)

        {

          return 0;

        }

      /* Reply describes memory byte by byte. */

      for (i = 0; i < todo; i++)

        myaddr[i] = buf[i + 2];

      myaddr += todo;

      memaddr += todo;

      len -= todo;

    }

  return origlen;

}

/* Read or write LEN bytes from inferior memory at MEMADDR,

   transferring to or from debugger address MYADDR.  Write to inferior

   if SHOULD_WRITE is nonzero.  Returns length of data written or

   read; 0 for error.  TARGET is unused.  */

/* ARGSUSED */

static int

sds_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int should_write,

                 struct mem_attrib *attrib, struct target_ops *target)

{

  int res;

  if (should_write)

    res = sds_write_bytes (memaddr, myaddr, len);

  else

    res = sds_read_bytes (memaddr, myaddr, len);

  return res;

}