/* IBM_PROLOG_BEGIN_TAG                                                   */
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/* $Source: src/hwpf/plat_utils.C $                                       */
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/* OpenPOWER sbe Project                                                  */
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/* Contributors Listed Below - COPYRIGHT 2015,2017                        */
/* [+] International Business Machines Corp.                              */
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/* IBM_PROLOG_END_TAG                                                     */

/**
 *  @file plat_utils.C
 *  @brief Implements fapi2 common utilities
 */

#include <stdint.h>
#include <fapi2_attribute_service.H>
#include <attribute_ids.H>
#include <return_code.H>
#include <plat_trace.H>
#include <target.H>
#include <sbeutil.H>
#include <sbeglobals.H>

namespace fapi2
{

    // Define own function rather than using PK function
    // This is required as PK function does not scale well for low
    // frequency till istep 2.7
    inline uint64_t delayCycles(uint64_t i_nanoSeconds )
    {
        return ( i_nanoSeconds/1000) * ( SBE_GLOBAL->sbefreq /(1000*1000));
    }
    /// @brief Delay this thread.
    ///
    ReturnCode delay(uint64_t i_nanoSeconds, uint64_t i_simCycles, bool i_fixed /* = false*/)
    {
        // void statements to keep the compiler from complaining
        // about unused variables.
        static_cast<void>(i_nanoSeconds);
        static_cast<void>(i_simCycles);

#ifndef __FAPI_DELAY_SIM__

        PkTimebase  target_time;
        PkTimebase  current_time;


        // Only execute if nanoSeconds is non-zero (eg a real wait)
        if (i_nanoSeconds)
        {

            target_time = pk_timebase_get() + delayCycles( i_nanoSeconds);
            current_time = pk_timebase_get();

            do
            {
                current_time = pk_timebase_get();
            } while (target_time > current_time);

        }
#else

        // Execute a tight loop that simply counts down the i_simCycles
        // value.

        // @todo This can might be optimized with a fused compare branch loop
        //    Note, though, that subwibnz instruction is optimized for word
        //      operations.   i_simCycles are uint64_t values so the upper
        //      word values needs to be accounted for.
        //
        //  Need to determine if this optimization is worth the effort.

#ifndef __FAPI_DELAY_PPE_SIM_CYCLES__
#define __FAPI_DELAY_PPE_SIM_CYCLES__ 8
#endif

        static const uint8_t NUM_OVERHEAD_INSTRS = 15;
        static const uint8_t NUM_LOOP_INSTRS = 4;
        static const uint64_t MIN_DELAY_CYCLES =
                ((NUM_OVERHEAD_INSTRS + NUM_LOOP_INSTRS) * __FAPI_DELAY_PPE_SIM_CYCLES__);

        uint64_t l_adjusted_simcycles;

        if (i_simCycles < MIN_DELAY_CYCLES)
            l_adjusted_simcycles = MIN_DELAY_CYCLES;
        else
            l_adjusted_simcycles = i_simCycles;

        uint64_t delay_loop_count =
            ((l_adjusted_simcycles - (NUM_OVERHEAD_INSTRS * __FAPI_DELAY_PPE_SIM_CYCLES__)) /
                        (NUM_LOOP_INSTRS * __FAPI_DELAY_PPE_SIM_CYCLES__));

        for (auto i = delay_loop_count; i > 0; --i) {
            // Force compiler not to optimize for loop
             asm("");
        }

#endif

        // replace with platform specific implementation
        return FAPI2_RC_SUCCESS;
    }

    ///
    /// @brief Queries the ATTR_NAME and ATTR_EC attributes
    ///
    ReturnCode queryChipEcAndName(
        const Target < fapi2::TARGET_TYPE_PROC_CHIP > & i_target,
        fapi2::ATTR_NAME_Type& o_chipName, fapi2::ATTR_EC_Type& o_chipEc )
    {

        FAPI_ATTR_GET_PRIVILEGED(fapi2::ATTR_NAME, i_target, o_chipName);

        FAPI_ATTR_GET_PRIVILEGED(fapi2::ATTR_EC, i_target, o_chipEc);

	return FAPI2_RC_SUCCESS;
    }
};