hw_eeprom.c

这个是LINUX下的GDB调度工具的源码

/* eeprom reads */

static unsigned8
toggle(hw_eeprom_device *eeprom,
       unsigned8 byte)
{
  eeprom->toggle_bit = eeprom->toggle_bit ^ 0x40; /* le-bit 6 */
  return eeprom->toggle_bit ^ byte;
}

static unsigned8
read_byte(device *me,
	  hw_eeprom_device *eeprom,
	  unsigned_word address)
{
  /* may need multiple iterations of this */
  while (1) {
    switch (eeprom->state) {

    case read_reset:
      return eeprom->memory[address];

    case autoselect:
      if ((address & 0xff) == 0x00)
	return eeprom->manufacture_code;
      else if ((address & 0xff) == 0x01)
	return eeprom->device_code;
      else
	return 0; /* not certain about this */

    case byte_programming:
      if (device_event_queue_time(me) > eeprom->program_finish_time) {
	finish_programming_byte(me, eeprom);
	eeprom->state = read_reset;
	continue;
      }
      else if (address == eeprom->byte_program_address) {
	return toggle(eeprom, eeprom->memory[address]);
      }
      else {
	/* trash that memory location */
	invalid_read(me, eeprom->state, address, "not byte program address");
	eeprom->memory[address] = (eeprom->memory[address]
				   & eeprom->byte_program_byte);
	return toggle(eeprom, eeprom->memory[eeprom->byte_program_address]);
      }

    case chip_erase:
      if (device_event_queue_time(me) > eeprom->program_finish_time) {
	finish_erasing_chip(me, eeprom);
	eeprom->state = read_reset;
	continue;
      }
      else {
	return toggle(eeprom, eeprom->memory[address]);
      }

    case sector_erase:
      if (device_event_queue_time(me) > eeprom->program_finish_time) {
	finish_erasing_sector(me, eeprom);
	eeprom->state = read_reset;
	continue;
      }
      else if (!eeprom->sectors[address / eeprom->sizeof_sector]) {
	/* read to wrong sector */
	invalid_read(me, eeprom->state, address, "sector not being erased");
	return toggle(eeprom, eeprom->memory[address]) & ~0x8;
      }
      else if (device_event_queue_time(me) > eeprom->sector_start_time) {
	return toggle(eeprom, eeprom->memory[address]) | 0x8;
      }
      else {
	return toggle(eeprom, eeprom->memory[address]) & ~0x8;
      }

    case sector_erase_suspend:
      if (!eeprom->sectors[address / eeprom->sizeof_sector]) {
	return eeprom->memory[address];
      }
      else {
	invalid_read(me, eeprom->state, address, "sector being erased");
	return eeprom->memory[address];
      }

    default:
      invalid_read(me, eeprom->state, address, "invalid state");
      return eeprom->memory[address];

    }
  }
  return 0;
}
		       
static unsigned
hw_eeprom_io_read_buffer(device *me,
			 void *dest,
			 int space,
			 unsigned_word addr,
			 unsigned nr_bytes,
			 cpu *processor,
			 unsigned_word cia)
{
  hw_eeprom_device *eeprom = (hw_eeprom_device*)device_data(me);
  int i;
  for (i = 0; i < nr_bytes; i++) {
    unsigned_word address = (addr + i) % eeprom->sizeof_memory;
    unsigned8 byte = read_byte(me, eeprom, address);
    ((unsigned8*)dest)[i] = byte;
  }
  return nr_bytes;
}


/* eeprom writes */

static void
write_byte(device *me,
	   hw_eeprom_device *eeprom,
	   unsigned_word address,
	   unsigned8 data)
{
  /* may need multiple transitions to process a write */
  while (1) {
    switch (eeprom->state) {

    case read_reset:
      if (address == 0x5555 && data == 0xaa)
	eeprom->state = write_nr_2;
      else if (data == 0xf0)
	eeprom->state = read_reset;
      else {
	invalid_write(me, eeprom->state, address, data, "unexpected");
	eeprom->state = read_reset;
      }
      return;

    case write_nr_2:
      if (address == 0x2aaa && data == 0x55)
	eeprom->state = write_nr_3;
      else {
	invalid_write(me, eeprom->state, address, data, "unexpected");
	eeprom->state = read_reset;
      }
      return;

    case write_nr_3:
      if (address == 0x5555 && data == 0xf0)
	eeprom->state = read_reset;
      else if (address == 0x5555 && data == 0x90)
	eeprom->state = autoselect;
      else if (address == 0x5555 && data == 0xa0) {
	eeprom->state = byte_program;
      }
      else if (address == 0x5555 && data == 0x80)
	eeprom->state = write_nr_4;
      else {
	invalid_write(me, eeprom->state, address, data, "unexpected");
	eeprom->state = read_reset;
      }
      return;

    case write_nr_4:
      if (address == 0x5555 && data == 0xaa)
	eeprom->state = write_nr_5;
      else {
	invalid_write(me, eeprom->state, address, data, "unexpected");
	eeprom->state = read_reset;
      }
      return;

    case write_nr_5:
      if (address == 0x2aaa && data == 0x55)
	eeprom->state = write_nr_6;
      else {
	invalid_write(me, eeprom->state, address, data, "unexpected");
	eeprom->state = read_reset;
      }
      return;

    case write_nr_6:
      if (address == 0x5555 && data == 0x10) {
	start_erasing_chip(me, eeprom);
	eeprom->state = chip_erase;
      }
      else {
	start_erasing_sector(me, eeprom, address);
	eeprom->sector_state = read_reset;
	eeprom->state = sector_erase;
      }
      return;

    case autoselect:
      if (data == 0xf0)
	eeprom->state = read_reset;
      else if (address == 0x5555 && data == 0xaa)
	eeprom->state = write_nr_2;
      else {
	invalid_write(me, eeprom->state, address, data, "unsupported address");
	eeprom->state = read_reset;
      }
      return;

    case byte_program:
      start_programming_byte(me, eeprom, address, data);
      eeprom->state = byte_programming;
      return;

    case byte_programming:
      if (device_event_queue_time(me) > eeprom->program_finish_time) {
	finish_programming_byte(me, eeprom);
	eeprom->state = read_reset;
	continue;
      }
      /* ignore it */
      return;

    case chip_erase:
      if (device_event_queue_time(me) > eeprom->program_finish_time) {
	finish_erasing_chip(me, eeprom);
	eeprom->state = read_reset;
	continue;
      }
      /* ignore it */
      return;

    case sector_erase:
      if (device_event_queue_time(me) > eeprom->program_finish_time) {
	finish_erasing_sector(me, eeprom);
	eeprom->state = eeprom->sector_state;
	continue;
      }
      else if (device_event_queue_time(me) > eeprom->sector_start_time
	       && data == 0xb0) {
	eeprom->sector_state = read_reset;
	eeprom->state = sector_erase_suspend;
      }
      else {
	if (eeprom->sector_state == read_reset
	    && address == 0x5555 && data == 0xaa)
	  eeprom->sector_state = write_nr_2;
	else if (eeprom->sector_state == write_nr_2
		 && address == 0x2aaa && data == 0x55)
	  eeprom->sector_state = write_nr_3;
	else if (eeprom->sector_state == write_nr_3
		 && address == 0x5555 && data == 0x80)
	  eeprom->sector_state = write_nr_4;
	else if (eeprom->sector_state == write_nr_4
		 && address == 0x5555 && data == 0xaa)
	  eeprom->sector_state = write_nr_5;
	else if (eeprom->sector_state == write_nr_5
		 && address == 0x2aaa && data == 0x55)
	  eeprom->sector_state = write_nr_6;
	else if (eeprom->sector_state == write_nr_6
		 && address != 0x5555 && data == 0x30) {
	  if (device_event_queue_time(me) > eeprom->sector_start_time) {
	    DTRACE(eeprom, ("sector erase command after window closed\n"));
	    eeprom->sector_state = read_reset;
	  }
	  else {
	    start_erasing_sector(me, eeprom, address);
	    eeprom->sector_state = read_reset;
	  }
	}
	else {
	  invalid_write(me, eeprom->state, address, data, state2a(eeprom->sector_state));
	  eeprom->state = read_reset;
	}
      }
      return;

    case sector_erase_suspend:
      if (data == 0x30)
	eeprom->state = sector_erase;
      else {
	invalid_write(me, eeprom->state, address, data, "not resume command");
	eeprom->state = read_reset;
      }
      return;

    }
  }
}

static unsigned
hw_eeprom_io_write_buffer(device *me,
			  const void *source,
			  int space,
			  unsigned_word addr,
			  unsigned nr_bytes,
			  cpu *processor,
			  unsigned_word cia)
{
  hw_eeprom_device *eeprom = (hw_eeprom_device*)device_data(me);
  int i;
  for (i = 0; i < nr_bytes; i++) {
    unsigned_word address = (addr + i) % eeprom->sizeof_memory;
    unsigned8 byte = ((unsigned8*)source)[i];
    write_byte(me, eeprom, address, byte);
  }
  return nr_bytes;
}


/* An instance of the eeprom */

typedef struct _hw_eeprom_instance {
  unsigned_word pos;
  hw_eeprom_device *eeprom;
  device *me;
} hw_eeprom_instance;

static void
hw_eeprom_instance_delete(device_instance *instance)
{
  hw_eeprom_instance *data = device_instance_data(instance);
  zfree(data);
}

static int
hw_eeprom_instance_read(device_instance *instance,
			void *buf,
			unsigned_word len)
{
  hw_eeprom_instance *data = device_instance_data(instance);
  int i;
  if (data->eeprom->state != read_reset)
    DITRACE(eeprom, ("eeprom not idle during instance read\n"));
  for (i = 0; i < len; i++) {
    ((unsigned8*)buf)[i] = data->eeprom->memory[data->pos];
    data->pos = (data->pos + 1) % data->eeprom->sizeof_memory;
  }
  return len;
}

static int
hw_eeprom_instance_write(device_instance *instance,
			 const void *buf,
			 unsigned_word len)
{
  hw_eeprom_instance *data = device_instance_data(instance);
  int i;
  if (data->eeprom->state != read_reset)
    DITRACE(eeprom, ("eeprom not idle during instance write\n"));
  for (i = 0; i < len; i++) {
    data->eeprom->memory[data->pos] = ((unsigned8*)buf)[i];
    data->pos = (data->pos + 1) % data->eeprom->sizeof_memory;
  }
  dump_eeprom(data->me, data->eeprom);
  return len;
}

static int
hw_eeprom_instance_seek(device_instance *instance,
		      unsigned_word pos_hi,
		      unsigned_word pos_lo)
{
  hw_eeprom_instance *data = device_instance_data(instance);
  if (pos_lo >= data->eeprom->sizeof_memory)
    device_error(data->me, "seek value 0x%lx out of range\n",
		 (unsigned long)pos_lo);
  data->pos = pos_lo;
  return 0;
}

static const device_instance_callbacks hw_eeprom_instance_callbacks = {
  hw_eeprom_instance_delete,
  hw_eeprom_instance_read,
  hw_eeprom_instance_write,
  hw_eeprom_instance_seek,
};

static device_instance *
hw_eeprom_create_instance(device *me,
			  const char *path,
			  const char *args)
{
  hw_eeprom_device *eeprom = device_data(me);
  hw_eeprom_instance *data = ZALLOC(hw_eeprom_instance);
  data->eeprom = eeprom;
  data->me = me;
  return device_create_instance_from(me, NULL,
				     data,
				     path, args,
				     &hw_eeprom_instance_callbacks);
}



static device_callbacks const hw_eeprom_callbacks = {
  { generic_device_init_address,
    hw_eeprom_init_data },
  { NULL, }, /* address */
  { hw_eeprom_io_read_buffer,
    hw_eeprom_io_write_buffer }, /* IO */
  { NULL, }, /* DMA */
  { NULL, }, /* interrupt */
  { NULL, }, /* unit */
  hw_eeprom_create_instance,
};

static void *
hw_eeprom_create(const char *name,
		 const device_unit *unit_address,
		 const char *args)
{
  hw_eeprom_device *eeprom = ZALLOC(hw_eeprom_device);
  return eeprom;
}



const device_descriptor hw_eeprom_device_descriptor[] = {
  { "eeprom", hw_eeprom_create, &hw_eeprom_callbacks },
  { NULL },
};

#endif /* _HW_EEPROM_C_ */