// Copyright Notice
// ================
// BOCHS is Copyright 1994-1999 by Kevin P. Lawton.
//
// BOCHS is commercial software.
//
// For more information, read the file 'LICENSE' included in the bochs
// distribution.  If you don't have access to this file, or have questions
// regarding the licensing policy, the author may be contacted via:
//
//     US Mail:  Kevin Lawton
//               439 Marrett Rd.
//               Lexington, MA 02421-7714
//
//     EMail:    bochs@world.std.com





#include "bochs.h"


#if BX_USE_CMOS_SMF
bx_cmos_c bx_cmos;
#define this (&bx_cmos)
#endif


// check that BX_NUM_CMOS_REGS is 64 or 128
#if (BX_NUM_CMOS_REGS == 64)
#elif (BX_NUM_CMOS_REGS == 128)
#else
#error "Invalid BX_NUM_CMOS_REGS value in config.h"
#endif


bx_cmos_c::bx_cmos_c(void)
{
}

bx_cmos_c::~bx_cmos_c(void)
{
  // nothing for now
}


  void
bx_cmos_c::init(bx_devices_c *d)
{
  unsigned i;

  // CMOS RAM & RTC

  BX_CMOS_THIS devices = d;

  BX_CMOS_THIS devices->register_io_read_handler(this,
       read_handler, 0x0070,
       "CMOS RAM");
  BX_CMOS_THIS devices->register_io_read_handler(this,
       read_handler,
       0x0071,
       "CMOS RAM");
  BX_CMOS_THIS devices->register_io_write_handler(this,
       write_handler,
       0x0070, "CMOS RAM");
  BX_CMOS_THIS devices->register_io_write_handler(this,
       write_handler,
       0x0071, "CMOS RAM");
  BX_CMOS_THIS devices->register_irq(8, "CMOS RTC");

  BX_CMOS_THIS s.periodic_timer_index =
    bx_pc_system.register_timer(this, periodic_timer_handler,
      1000000, 1,0); // continuous, not-active
  BX_CMOS_THIS s.one_second_timer_index =
    bx_pc_system.register_timer(this, one_second_timer_handler,
      1000000, 1,0); // continuous, not-active

  for (i=0; i<BX_NUM_CMOS_REGS; i++) {
    BX_CMOS_THIS s.reg[i] = 0;
    }

#if BX_USE_SPECIFIED_TIME0 == 0
  // ??? this will not be correct for using an image file.
  // perhaps take values in CMOS and work backwards to find
  // s.timeval from values read in.
  BX_CMOS_THIS s.timeval = time(NULL);
#else
  BX_CMOS_THIS s.timeval = BX_USE_SPECIFIED_TIME0;
#endif

  if (bx_options.cmos.time0 == 1)
          BX_CMOS_THIS s.timeval = time(NULL);
  else if (bx_options.cmos.time0 != 0)
          BX_CMOS_THIS s.timeval = bx_options.cmos.time0;

  bx_printf("[cmos] Setting initial clock to: %s",
    ctime(&(BX_CMOS_THIS s.timeval)));

  update_clock();

  // load CMOS from image file if requested.
  if (bx_options.cmos.cmosImage) {
    // CMOS image file requested
    int fd, ret;
    struct stat stat_buf;

    fd = open(bx_options.cmos.path, O_RDONLY
#ifdef O_BINARY
            | O_BINARY
#endif
             );
    if (fd < 0) {
      perror("trying to open cmos image file.\n");
      bx_panic("trying to open cmos image file '%s'\n",
        bx_options.cmos.path);
      }
    ret = fstat(fd, &stat_buf);
    if (ret) {
      bx_panic("CMOS: could not fstat() image file.\n");
      }
    if (stat_buf.st_size != BX_NUM_CMOS_REGS) {
      bx_panic("CMOS: image file not same size as BX_NUM_CMOS_REGS.\n");
      }

    ret = read(fd, (bx_ptr_t) BX_CMOS_THIS s.reg, BX_NUM_CMOS_REGS);
    if (ret != BX_NUM_CMOS_REGS) {
      bx_panic("CMOS: error reading cmos file.\n");
      }
    close(fd);
    bx_printf("CMOS: successfuly read from image file '%s'.\n",
      bx_options.cmos.path);
    }
  else {
    // CMOS values generated
    BX_CMOS_THIS s.reg[0x0a] = 0x26;
    BX_CMOS_THIS s.reg[0x0b] = 0x02;
    BX_CMOS_THIS s.reg[0x0c] = 0x00;
    BX_CMOS_THIS s.reg[0x0d] = 0x80;
    }
}

  void
bx_cmos_c::reset(void)
{
  BX_CMOS_THIS s.cmos_mem_address = 0;

  // RESET affects the following registers:
  //  CRA: no effects
  //  CRB: bits 4,5,6 forced to 0
  //  CRC: bits 4,5,6,7 forced to 0
  //  CRD: no effects
  BX_CMOS_THIS s.reg[0x0b] &= 0x8f;
  BX_CMOS_THIS s.reg[0x0c] = 0;

  // One second timer for updating clock & alarm functions
  bx_pc_system.activate_timer(BX_CMOS_THIS s.one_second_timer_index,
                              1000000, 1);

  // handle periodic interrupt rate select
  BX_CMOS_THIS CRA_change();
}

  void
bx_cmos_c::CRA_change(void)
{
  unsigned nibble;

  // Periodic Interrupt timer
  nibble = BX_CMOS_THIS s.reg[0x0a] & 0x0f;
  if (nibble == 0) {
    // No Periodic Interrupt Rate when 0, deactivate timer
    bx_pc_system.deactivate_timer(BX_CMOS_THIS s.periodic_timer_index);
    BX_CMOS_THIS s.periodic_interval_usec = (Bit32u) -1; // max value
    }
  else {
    // values 0001b and 0010b are the same as 1000b and 1001b
    if (nibble <= 2)
      nibble += 7;
    BX_CMOS_THIS s.periodic_interval_usec = (unsigned) (1000000.0L /
        (32768.0L / (1 << (nibble - 1))));

    // if Periodic Interrupt Enable bit set, activate timer
    if ( BX_CMOS_THIS s.reg[0x0b] & 0x40 )
      bx_pc_system.activate_timer(BX_CMOS_THIS s.periodic_timer_index,
        BX_CMOS_THIS s.periodic_interval_usec, 1);
    else
      bx_pc_system.deactivate_timer(BX_CMOS_THIS s.periodic_timer_index);
    }
}


  // static IO port read callback handler
  // redirects to non-static class handler to avoid virtual functions

  Bit32u
bx_cmos_c::read_handler(void *this_ptr, Bit32u address, unsigned io_len)
{
#if !BX_USE_CMOS_SMF
  bx_cmos_c *class_ptr = (bx_cmos_c *) this_ptr;

  return( class_ptr->read(address, io_len) );
}

  Bit32u
bx_cmos_c::read(Bit32u address, unsigned io_len)
{
#else
  UNUSED(this_ptr);
#endif
  Bit8u ret8;

  if (io_len > 1)
    bx_panic("cmos: io read from address %08x len=%u\n",
             (unsigned) address, (unsigned) io_len);

  if (bx_dbg.cmos)
    bx_printf("CMOS read of CMOS register 0x%x\n",
      (unsigned) BX_CMOS_THIS s.cmos_mem_address);


  switch (address) {
    case 0x0071:
      if (BX_CMOS_THIS s.cmos_mem_address >= BX_NUM_CMOS_REGS) {
        bx_panic("unsupported cmos io read, register(0x%02x)!\n",
            (unsigned) BX_CMOS_THIS s.cmos_mem_address);
        }

      ret8 = BX_CMOS_THIS s.reg[BX_CMOS_THIS s.cmos_mem_address];
      // all bits of Register C are cleared after a read occurs.
      if (BX_CMOS_THIS s.cmos_mem_address == 0x0c)
        BX_CMOS_THIS s.reg[0x0c] = 0x00;
      return(ret8);
      break;

    default:
      bx_panic("unsupported cmos read, address=%0x%x!\n",
        (unsigned) address);
      return(0);
      break;
    }
}


  // static IO port write callback handler
  // redirects to non-static class handler to avoid virtual functions

  void
bx_cmos_c::write_handler(void *this_ptr, Bit32u address, Bit32u value, unsigned io_len)
{
#if !BX_USE_CMOS_SMF
  bx_cmos_c *class_ptr = (bx_cmos_c *) this_ptr;

  class_ptr->write(address, value, io_len);
}

  void
bx_cmos_c::write(Bit32u address, Bit32u value, unsigned io_len)
{
#else
  UNUSED(this_ptr);
#endif  // !BX_USE_CMOS_SMF

  if (io_len > 1)
    bx_panic("cmos: io write to address %08x len=%u\n",
             (unsigned) address, (unsigned) io_len);

  if (bx_dbg.cmos)
    bx_printf("CMOS write to address: 0x%x = 0x%x\n",
      (unsigned) address, (unsigned) value);


  switch (address) {
    case 0x0070:
#if (BX_NUM_CMOS_REGS == 64)
      BX_CMOS_THIS s.cmos_mem_address = value & 0x3F;
#else
      BX_CMOS_THIS s.cmos_mem_address = value & 0x7F;
#endif
      break;

    case 0x0071:
      if (BX_CMOS_THIS s.cmos_mem_address >= BX_NUM_CMOS_REGS) {
        bx_panic("unsupported cmos io write, register(0x%02x)=%02x!\n",
            (unsigned) BX_CMOS_THIS s.cmos_mem_address, (unsigned) value);
        return;
        }
      switch (BX_CMOS_THIS s.cmos_mem_address) {
        case 0x00: // seconds
        case 0x01: // seconds alarm
        case 0x02: // minutes
        case 0x03: // minutes alarm
        case 0x04: // hours
        case 0x05: // hours alarm
        case 0x06: // day of the week
        case 0x07: // day of the month
        case 0x08: // month
        case 0x09: // year
          //bx_printf("CMOS: write reg %02xh: value = %02xh\n",
          //    (unsigned) BX_CMOS_THIS s.cmos_mem_address, (unsigned) value);
          BX_CMOS_THIS s.reg[BX_CMOS_THIS s.cmos_mem_address] = value;
          return;
          break;

        case 0x0a: // Control Register A
          // bit 7: Update in Progress (read-only)
          //   1 = signifies time registers will be updated within 244us
          //   0 = time registers will not occur before 244us
          //   note: this bit reads 0 when CRB bit 7 is 1
          // bit 6..4: Divider Chain Control
          //   000 oscillator disabled
          //   001 oscillator disabled
          //   010 Normal operation
          //   011 TEST
          //   100 TEST
          //   101 TEST
          //   110 Divider Chain RESET
          //   111 Divider Chain RESET
          // bit 3..0: Periodic Interrupt Rate Select
          //   0000 None
          //   0001 3.90625  ms
          //   0010 7.8125   ms
          //   0011 122.070  us
          //   0100 244.141  us
          //   0101 488.281  us
          //   0110 976.562  us
          //   0111 1.953125 ms
          //   1000 3.90625  ms
          //   1001 7.8125   ms
          //   1010 15.625   ms
          //   1011 31.25    ms
          //   1100 62.5     ms
          //   1101 125      ms
          //   1110 250      ms
          //   1111 500      ms

          unsigned dcc;
          dcc = (value >> 4) & 0x07;
          if (dcc != 0x02) {
            bx_panic("cmos: CRA: divider chain control 0x%x\n", dcc);
            }
          BX_CMOS_THIS s.reg[0x0a] = value & 0x7f;
          BX_CMOS_THIS CRA_change();
          return;
          break;

        case 0x0b: // Control Register B
          // bit 0: Daylight Savings Enable
          //   1 = enable daylight savings
          //   0 = disable daylight savings
          // bit 1: 24/12 houre mode
          //   1 = 24 hour format
          //   0 = 12 hour format
          // bit 2: Data Mode
          //   1 = binary format
          //   0 = BCD format
          // bit 3: "square wave enable"
          //   Not supported and always read as 0
          // bit 4: Update Ended Interrupt Enable
          //   1 = enable generation of update ended interrupt
          //   0 = disable
          // bit 5: Alarm Interrupt Enable
          //   1 = enable generation of alarm interrupt
          //   0 = disable
          // bit 6: Periodic Interrupt Enable
          //   1 = enable generation of periodic interrupt
          //   0 = disable
          // bit 7: Set mode
          //   1 = user copy of time is "frozen" allowing time registers
          //       to be accessed without regard for an occurance of an update
          //   0 = time updates occur normally

          // can not handle binary or 12-hour mode yet.
          if (value & 0x04)
            bx_panic("cmos: write status reg B, binary format enabled.\n");
          if ( !(value & 0x02) )
            bx_panic("cmos: write status reg B, 12 hour mode enabled.\n");

          value &= 0xf7; // bit3 always 0
          // Note: setting bit 7 clears bit 4
          if (value & 0x80)
            value &= 0xef;

          unsigned prev_CRB;
          prev_CRB = BX_CMOS_THIS s.reg[0x0b];
          BX_CMOS_THIS s.reg[0x0b] = value;
          if ( (prev_CRB & 0x40) != (value & 0x40) ) {
            // Periodic Interrupt Enabled changed
            if (prev_CRB & 0x40) {
              // transition from 1 to 0, deactivate timer
              bx_pc_system.deactivate_timer(
                BX_CMOS_THIS s.periodic_timer_index);
              }
            else {
              // transition from 0 to 1
              // if rate select is not 0, activate timer
              if ( (BX_CMOS_THIS s.reg[0x0a] & 0x0f) != 0 ) {
                bx_pc_system.activate_timer(
                  BX_CMOS_THIS s.periodic_timer_index,
                  BX_CMOS_THIS s.periodic_interval_usec, 1);
                }
              }
            }
          return;
          break;

        case 0x0c: // Control Register C
        case 0x0d: // Control Register D
          bx_panic("cmos: write to control register 0x%x (read-only)\n",
                   BX_CMOS_THIS s.cmos_mem_address);
          break;

        case 0x0e: // diagnostic status
          bx_printf("CMOS: write register 0Eh: %02x\n", (unsigned) value);
          break;

	case 0x0f: // shutdown status
          switch (value) {
            case 0x00: /* proceed with normal POST (soft reset) */
              if (bx_dbg.reset)
                bx_printf("CMOS: Reg 0F set to 0: shutdown action = normal POST\n");
              break;
            case 0x02: /* shutdown after memory test */
              if (bx_dbg.reset)
                bx_printf("CMOS: Reg 0Fh: request to change shutdown action"
                             " to shutdown after memory test\n");
              break;
            case 0x03:
              bx_printf ("CMOS: Reg 0Fh(03) : Shutdown after memory test !\n");
              break;
            case 0x04: /* jump to disk bootstrap routine */
              bx_printf("CMOS: Reg 0Fh: request to change shutdown action "
                             "to jump to disk bootstrap routine.\n");
              break;
            case 0x06:
              bx_printf ("CMOS: Reg 0Fh(06) : Shutdown after memory test !\n");
              break;
            case 0x09: /* return to BIOS extended memory block move
                       (interrupt 15h, func 87h was in progress) */
              if (bx_dbg.reset)
                bx_printf("CMOS: Reg 0Fh: request to change shutdown action "
                             "to return to BIOS extended memory block move.\n");
              break;
            case 0x0a: /* jump to DWORD pointer at 40:67 */
              if (bx_dbg.reset)
                bx_printf("CMOS: Reg 0Fh: request to change shutdown action"
                             " to jump to DWORD at 40:67\n");
              break;
            default:
              bx_panic("unsupported cmos io write to reg F, case %x!\n",
                (unsigned) value);
              break;
            }
          break;

        default:
          bx_printf("CMOS: write reg %02xh: value = %02xh\n",
            (unsigned) BX_CMOS_THIS s.cmos_mem_address, (unsigned) value);
          break;
        }

      BX_CMOS_THIS s.reg[BX_CMOS_THIS s.cmos_mem_address] = value;
      break;
    }
}


  void
bx_cmos_c::checksum_cmos(void)
{
  unsigned i;
  Bit16u sum;

  sum = 0;
  for (i=0x10; i<=0x2d; i++) {
    sum += BX_CMOS_THIS s.reg[i];
    }
  BX_CMOS_THIS s.reg[0x2e] = (sum >> 8) & 0xff; /* checksum high */
  BX_CMOS_THIS s.reg[0x2f] = (sum & 0xff);      /* checksum low */
}

  void
bx_cmos_c::periodic_timer_handler(void *this_ptr)
{
  bx_cmos_c *class_ptr = (bx_cmos_c *) this_ptr;

  // if periodic interrupts are enabled, trip IRQ 8, and
  // update status register C
  if (class_ptr->s.reg[0x0b] & 0x40) {
    class_ptr->s.reg[0x0c] |= 0xc0; // Interrupt Request, Periodic Int
    class_ptr->devices->pic->trigger_irq(8);
    }
}

  void
bx_cmos_c::one_second_timer_handler(void *this_ptr)
{
  bx_cmos_c *class_ptr = (bx_cmos_c *) this_ptr;

  // update internal time/date buffer
  class_ptr->s.timeval++;

  // Dont update CMOS user copy of time/date if CRB bit7 is 1
  // Nothing else do to
  if (class_ptr->s.reg[0x0b] & 0x80)
    return;

  update_clock();

  // if update interrupts are enabled, trip IRQ 8, and
  // update status register C
  if (class_ptr->s.reg[0x0b] & 0x10) {
    class_ptr->s.reg[0x0c] |= 0x90; // Interrupt Request, Update Ended
    class_ptr->devices->pic->trigger_irq(8);
    }

  // compare CMOS user copy of time/date to alarm time/date here
  if (class_ptr->s.reg[0x0b] & 0x20) {
    // Alarm interrupts enabled
    Boolean alarm_match = 1;
    if ( (class_ptr->s.reg[0x01] & 0xc0) != 0xc0 ) {
      // seconds alarm not in dont care mode
      if (class_ptr->s.reg[0x00] != class_ptr->s.reg[0x01])
        alarm_match = 0;
      }
    if ( (class_ptr->s.reg[0x03] & 0xc0) != 0xc0 ) {
      // minutes alarm not in dont care mode
      if (class_ptr->s.reg[0x02] != class_ptr->s.reg[0x03])
        alarm_match = 0;
      }
    if ( (class_ptr->s.reg[0x05] & 0xc0) != 0xc0 ) {
      // hours alarm not in dont care mode
      if (class_ptr->s.reg[0x04] != class_ptr->s.reg[0x05])
        alarm_match = 0;
      }
    if (alarm_match) {
      class_ptr->s.reg[0x0c] |= 0xa0; // Interrupt Request, Alarm Int
      class_ptr->devices->pic->trigger_irq(8);
      }
    }
}


  void
bx_cmos_c::update_clock()
{
  struct tm *time_calendar;
  unsigned year, month, day, century;
  Bit8u val_bcd;

  time_calendar = localtime(& BX_CMOS_THIS s.timeval);

  // update seconds
  val_bcd =
     ((time_calendar->tm_sec  / 10) << 4) |
     (time_calendar->tm_sec % 10);
  BX_CMOS_THIS s.reg[0x00] = val_bcd;

  // update minutes
  val_bcd =
     ((time_calendar->tm_min  / 10) << 4) |
     (time_calendar->tm_min % 10);
  BX_CMOS_THIS s.reg[0x02] = val_bcd;

  // update hours
  val_bcd =
     ((time_calendar->tm_hour  / 10) << 4) |
     (time_calendar->tm_hour % 10);
  BX_CMOS_THIS s.reg[0x04] = val_bcd;

  // update day of the week
  day = time_calendar->tm_wday + 1; // 0..6 to 1..7
  BX_CMOS_THIS s.reg[0x06] = ((day / 10) << 4) | (day % 10);

  // update day of the month
  day = time_calendar->tm_mday;
  BX_CMOS_THIS s.reg[0x07] = ((day / 10) << 4) | (day % 10);

  // update month
  month   = time_calendar->tm_mon + 1;
  BX_CMOS_THIS s.reg[0x08] = ((month / 10) << 4) | (month % 10);

  // update year
  year = time_calendar->tm_year % 100;
  BX_CMOS_THIS s.reg[0x09] = ((year  / 10) << 4) | (year % 10);

  // update century
  century = (time_calendar->tm_year / 100) + 19;
  BX_CMOS_THIS s.reg[0x32] = ((century  / 10) << 4) | (century % 10);
}
