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/****************************************************************************
 *                                                                          *
 * FILE NAME                                               VERSION          *
 *      mai_tid.c                                          MAPI 0.05        *
 *                                                                          *
 * DESCRIPTION                                                              *
 *      This file contains the code for the TID allocation API              *
 *                                                                          *
 *                                                                          *
 * DATA STRUCTURES                                                          *
 *      None                                                                *
 *                                                                          *
 ****************************************************************************/

/*
 * Local definitions:
 *
 *
 */

#include "mai_l.h"		/* Local mai function definitions */
#include "ispinlock.h"

/*
 * FUNCTION
 *      mai_alloc_tid
 *
 * DESCRIPTION
 *      Returns a unique TID to be tack on to mads and filters.
 *
 *
 * INPUTS
 *      fd       A valid channel handle
 *      *tid     Location to copy the TID to.
 *
 * OUTPUTS
 *      VSTATUS_OK
 *      VSTATUS_ILLPARM
 *
 * HISTORY
 *      NAME      DATE          REMARKS
 *      PAW     06/4/01 Initial entry
 */
static ATOMIC_UINT layer_counter=0;

Status_t
mai_alloc_tid(IBhandle_t fd, uint8_t mclass, uint64_t * tid)
{
    int             rc = 0;
    ATOMIC_UINT     counter = AtomicIncrement(&layer_counter);

    IB_ENTER(__func__, fd, 0, 0, 0);

    if (!gMAI_INITIALIZED)
      {
	  rc = VSTATUS_UNINIT;
	  IB_LOG_ERROR0("MAPI library not initialized");
	  return rc;
      }

#if defined(CAL_IBACCESS)
    // For the embedded SM, inject the process ID into the TID
    // to ensure responses are delivered to the correct destination.
    Threadname_t    pid;
    if ((rc = vs_thread_name(&pid)) != VSTATUS_OK) {
        IB_EXIT(__func__, rc);
        return (rc);
    }
    uint64_t        mpid = (uint64_t) pid;
    *tid = (((mpid & 0xffffff) << 40) |	// 24 bits for pid
	        ((counter & 0xffff) << 24));// 16 bits for counter
#elif defined(IB_STACK_OPENIB)
	// OpenIB reserves the top 32 bits of the TID for its own use.
	// (See infiniband/core/user_mad.c.)
	*tid = (counter & 0xffffffff);      // 32 bits for counter
#else
#error Either CAL_IBACCESS or IB_STACK_OPENIB must be defined.
#endif

    IB_EXIT(__func__, rc);
    return (rc);
}

/*
 * mai_increment_tid
 *   Given a tid allocated by mai_alloc_tid, computes a new unique TID
 *
 * INPUTS
 *      the previous tid
 *
 * RETURNS
 *      new tid
 */
uint64_t
mai_increment_tid(uint64_t tid)
{
    ATOMIC_UINT     counter = AtomicIncrement(&layer_counter);

#if defined(CAL_IBACCESS)
    return (tid & 0xffffff0000ffffffULL) | ((counter & 0xffff) << 24);
#elif defined(IB_STACK_OPENIB)
    return (tid & 0xffffffff00000000ULL) | (counter & 0xffffffff);
#else
#error Either CAL_IBACCESS or IB_STACK_OPENIB must be defined.
#endif
}