ext/hal/altera/drivers/altera_avalon_sysid/HAL/src/altera_avalon_sysid.c

/******************************************************************************
*                                                                             *
* License Agreement                                                           *
*                                                                             *
* Copyright (c) 2003 Altera Corporation, San Jose, California, USA.           *
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******************************************************************************/

#include "altera_avalon_sysid.h"
#include "altera_avalon_sysid_regs.h"
#include "alt_types.h"
#include <io.h>

/*
*  This component is special: there's only one of it.
*  Therefore we can dispense with a bunch of complexity
*  normally associated with components, such as specialized
*  structs containing parameter info, and instead use that
*  info by name directly out of system.h.  A downside of this
*  approach is that each time the system is regenerated, and
*  system.h changes, this file must be recompiled.  Fortunately
*  this file is, and is likely to remain, quite small.
*/
#include "system.h"

#ifdef SYSID_BASE
/*
*  return values:
*    0 if the hardware and software appear to be in sync
*    1 if software appears to be older than hardware
*   -1 if hardware appears to be older than software
*/

alt_32 alt_avalon_sysid_test(void)
{
  /* Read the hardware-tag, aka value0, from the hardware. */
  alt_u32 hardware_id = IORD_ALTERA_AVALON_SYSID_ID(SYSID_BASE);

  /* Read the time-of-generation, aka value1, from the hardware register. */
  alt_u32 hardware_timestamp = IORD_ALTERA_AVALON_SYSID_TIMESTAMP(SYSID_BASE);

  /* Return 0 if the hardware and software appear to be in sync. */
  if ((SYSID_TIMESTAMP == hardware_timestamp) && (SYSID_ID == hardware_id))
  {
    return 0;
  }

  /*
  *  Return 1 if software appears to be older than hardware (that is,
  *  the value returned by the hardware is larger than that recorded by
  *  the generator function).
  *  If the hardware time happens to match the generator program's value
  *  (but the hardware tag, value0, doesn't match or 0 would have been
  *  returned above), return an arbitrary value, let's say -1.
  */
  return ((alt_32)(hardware_timestamp - SYSID_TIMESTAMP)) > 0 ? 1 : -1;
}
#endif