spd_factory.C

/* IBM_PROLOG_BEGIN_TAG                                                   */
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/* $Source: src/import/chips/p9/procedures/hwp/memory/lib/spd/spd_factory.C $ */
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///
/// @file spd_factory.C
/// @brief SPD factory and functions
///
// *HWP HWP Owner: Andre Marin <aamarin@us.ibm.com>
// *HWP HWP Backup: Brian Silver <bsilver@us.ibm.com>
// *HWP Team: Memory
// *HWP Level: 2
// *HWP Consumed by: HB:FSP

// std lib
#include <map>
#include <vector>

// fapi2
#include <fapi2.H>
#include <fapi2_spd_access.H>

// mss lib
#include <lib/spd/spd_factory.H>
#include <generic/memory/lib/spd/common/ddr4/spd_decoder_ddr4.H>
#include <generic/memory/lib/spd/rdimm/ddr4/rdimm_decoder_ddr4.H>
#include <generic/memory/lib/spd/lrdimm/ddr4/lrdimm_decoder_ddr4.H>
#include <generic/memory/lib/spd/common/rcw_settings.H>
#include <generic/memory/lib/spd/rdimm/ddr4/rdimm_raw_cards.H>
#include <generic/memory/lib/spd/lrdimm/ddr4/lrdimm_raw_cards.H>
#include <generic/memory/lib/spd/spd_checker.H>
#include <generic/memory/lib/utils/c_str.H>
#include <lib/utils/conversions.H>
#include <generic/memory/lib/utils/find.H>

using fapi2::TARGET_TYPE_MCA;
using fapi2::TARGET_TYPE_MCS;
using fapi2::TARGET_TYPE_DIMM;
using fapi2::FAPI2_RC_SUCCESS;

namespace mss
{
namespace spd
{

enum factory_byte_extract
{
    // Byte 1
    ENCODING_LEVEL_START = 0,  ///< SPD encoding level start bit
    ENCODING_LEVEL_LEN = 4,    ///< SPD encoding level bit length

    ADDITIONS_LEVEL_START = 4, ///< SPD additions level start bit
    ADDITIONS_LEVEL_LEN = 4,   ///< SPD additions level bit length

    // Byte 3
    BASE_MODULE_START = 4,     ///< SPD base module start bit
    BASE_MODULE_LEN = 4,       ///< SPD base module bit length
};

///
/// @brief       Decodes SPD Revision encoding level
/// @param[in]   i_target dimm target
/// @param[in]   i_spd_data SPD data
/// @param[out]  o_value encoding revision num
/// @return      FAPI2_RC_SUCCESS if okay
/// @note        Decodes SPD Byte 1 (3~0).
/// @note        Item JC-45-2220.01x
/// @note        Page 14-15
/// @note        DDR4 SPD Document Release 3
///
fapi2::ReturnCode rev_encoding_level(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
                                     const std::vector<uint8_t>& i_spd_data,
                                     uint8_t& o_value)
{
    constexpr size_t BYTE_INDEX = 1;
    constexpr field_t ENCODING_LEVEL{BYTE_INDEX, ENCODING_LEVEL_START, ENCODING_LEVEL_LEN};

    // Extracting desired bits
    const uint8_t l_field_bits = extract_spd_field(i_target, ENCODING_LEVEL, i_spd_data);
    FAPI_DBG("%s. Field Bits value: %d", mss::c_str(i_target), l_field_bits);

    // Check that value is valid
    constexpr size_t UNDEFINED = 0xF; // per JEDEC spec this value is undefined
    FAPI_TRY( mss::check::spd::fail_for_invalid_value(i_target,
              (l_field_bits != UNDEFINED),
              ENCODING_LEVEL.iv_byte,
              l_field_bits,
              "Failed check on SPD rev encoding level") );

    // Update output only after check passes
    o_value = l_field_bits;

    // Print decoded info
    FAPI_INF("%s. Rev - Encoding Level : %d",
             mss::c_str(i_target),
             o_value);

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief       Decodes SPD Revision additions level
/// @param[in]   i_target dimm target
/// @param[in]  i_spd_data SPD data
/// @param[out]  o_value additions revision num
/// @return      FAPI2_RC_SUCCESS if okay
/// @note        Decodes SPD Byte 1 (bits 7~4).
/// @note        Item JC-45-2220.01x
/// @note        Page 14-15
/// @note        DDR4 SPD Document Release 3
///
fapi2::ReturnCode rev_additions_level(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
                                      const std::vector<uint8_t>& i_spd_data,
                                      uint8_t& o_value)
{
    constexpr size_t BYTE_INDEX = 1;
    constexpr field_t ADDITIONS_LEVEL{BYTE_INDEX, ADDITIONS_LEVEL_START, ADDITIONS_LEVEL_LEN};

    // Extracting desired bits
    const uint8_t l_field_bits = extract_spd_field(i_target, ADDITIONS_LEVEL, i_spd_data);
    FAPI_DBG("%s. Field Bits value: %d", mss::c_str(i_target), l_field_bits);

    // Check that value is valid
    constexpr size_t UNDEFINED = 0xF; // per JEDEC spec this value is undefined

    FAPI_TRY( mss::check::spd::fail_for_invalid_value(i_target,
              (l_field_bits != UNDEFINED),
              ADDITIONS_LEVEL.iv_byte,
              l_field_bits,
              "Failed check on SPD rev encoding level") );

    // Update output only after check passes
    o_value = l_field_bits;

    // Print decoded info
    FAPI_INF("%s. Rev - Additions Level : %d",
             mss::c_str(i_target),
             o_value);

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief      Decodes base module type (DIMM type) from SPD
/// @param[in]  i_target dimm target
/// @param[in]  i_spd_data SPD data
/// @param[out] o_value base module type
/// @return     FAPI2_RC_SUCCESS if okay
/// @note       Decodes SPD Byte 3 (bits 3~0)
/// @note       Item JC-45-2220.01x
/// @note       Page 17
/// @note       DDR4 SPD Document Release 3
///
fapi2::ReturnCode base_module_type(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
                                   const std::vector<uint8_t>& i_spd_data,
                                   uint8_t& o_value)
{
    // =========================================================
    // Byte 3 maps
    // Item JC-45-2220.01x
    // Page 17
    // DDR4 SPD Document Release 3
    // Byte 3 (0x003): Key Byte / Module Type
    // =========================================================
    static const std::vector<std::pair<uint8_t, uint8_t> > BASE_MODULE_TYPE_MAP =
    {
        //{key byte, dimm type}
        {1, fapi2::ENUM_ATTR_EFF_DIMM_TYPE_RDIMM},
        {2, fapi2::ENUM_ATTR_EFF_DIMM_TYPE_UDIMM},
        {4, fapi2::ENUM_ATTR_EFF_DIMM_TYPE_LRDIMM}
        // All others reserved or not supported
    };

    constexpr size_t BYTE_INDEX = 3;
    constexpr field_t BASE_MODULE{BYTE_INDEX, BASE_MODULE_START, BASE_MODULE_LEN};

    // Extracting desired bits
    const uint8_t l_field_bits = extract_spd_field(i_target, BASE_MODULE, i_spd_data);
    FAPI_DBG("%s. Field Bits value: %d", mss::c_str(i_target), l_field_bits);

    // Check that value is valid
    const bool l_is_val_found = find_value_from_key(BASE_MODULE_TYPE_MAP, l_field_bits, o_value);

    FAPI_TRY( mss::check::spd::fail_for_invalid_value(i_target,
              l_is_val_found,
              BASE_MODULE.iv_byte,
              l_field_bits,
              "Failed check on Base Module Type") );

    FAPI_INF("%s. Base Module Type: %d",
             mss::c_str(i_target),
             o_value);

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief       Decodes DRAM Device Type
/// @param[in]   i_target dimm target
/// @param[in]   i_spd_data SPD data
/// @param[out]  o_value dram device type enumeration
/// @return      FAPI2_RC_SUCCESS if okay
/// @note        Decodes SPD Byte 2
/// @note        Item JC-45-2220.01x
/// @note        Page 16
/// @note        DDR4 SPD Document Release 3
///
fapi2::ReturnCode dram_device_type(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
                                   const std::vector<uint8_t>& i_spd_data,
                                   uint8_t& o_value)
{
    // =========================================================
    // Byte 2 maps
    // Item JC-45-2220.01x
    // Page 16
    // DDR4 SPD Document Release 3
    // Byte 2 (0x002): Key Byte / DRAM Device Type
    // =========================================================
    static const std::vector<std::pair<uint8_t, uint8_t> > DRAM_GEN_MAP =
    {
        //{key value, dram gen}
        {0x0B, fapi2::ENUM_ATTR_EFF_DRAM_GEN_DDR3},
        {0x0C, fapi2::ENUM_ATTR_EFF_DRAM_GEN_DDR4}
        // Other key bytes reserved or not supported
    };

    constexpr size_t BYTE_INDEX = 2;
    const uint8_t l_raw_byte = i_spd_data[BYTE_INDEX];

    // Trace in the front assists w/ debug
    FAPI_INF("%s SPD data at Byte %d: 0x%llX.",
             mss::c_str(i_target),
             BYTE_INDEX,
             l_raw_byte);

    // Find map value
    const bool l_is_val_found = mss::find_value_from_key(DRAM_GEN_MAP, l_raw_byte, o_value);

    FAPI_TRY( mss::check::spd:: fail_for_invalid_value(i_target,
              l_is_val_found,
              BYTE_INDEX,
              l_raw_byte,
              "Failed check on SPD dram device type") );

    // Print decoded info
    FAPI_INF("%s Device type : %d",
             mss::c_str(i_target),
             o_value);

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief Decodes reference raw card
/// @param[in] i_target dimm target
/// @param[in] i_spd_data SPD data
/// @param[out] o_output encoding from SPD
/// @return FAPI2_RC_SUCCESS if okay
/// @note SPD Byte 130 (Bits 7~0)
/// @note Item JEDEC Standard No. 21-C
/// @note DDR4 SPD Document Release 2
/// @Note Page 4.1.2.12 - 49
///
fapi2::ReturnCode reference_raw_card(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
                                     const std::vector<uint8_t>& i_spd_data,
                                     uint8_t& o_output)
{
    // Extracting desired bits
    constexpr size_t BYTE_INDEX = 130;

    // Trace in the front assists w/ debug
    FAPI_INF("%s SPD data at Byte %d: 0x%llX.",
             mss::c_str(i_target),
             BYTE_INDEX,
             i_spd_data[BYTE_INDEX]);

    // Byte taken directly, all bits are an encoding value so no fail check
    o_output = i_spd_data[BYTE_INDEX];

    FAPI_INF("%s. Reference raw card: %d",
             mss::c_str(i_target),
             o_output);

    return fapi2::FAPI2_RC_SUCCESS;
}

///
/// @brief Helper function to set dimm type attribute
/// @param[in] i_target dimm target
/// @param[in] i_spd_data SPD data
/// @param[out] o_dimm_type dimm type encoding needed by factory
/// @return FAPI2_RC_SUCCESS if okay
///
static fapi2::ReturnCode dimm_type_setter(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
        const std::vector<uint8_t>& i_spd_data,
        uint8_t& o_dimm_type)
{
    const auto l_port_num = index( find_target<TARGET_TYPE_MCA>(i_target) );
    const auto l_dimm_num = index(i_target);
    const auto l_mcs = mss::find_target<TARGET_TYPE_MCS>(i_target);

    // Get dimm type & set attribute (needed by c_str)
    uint8_t l_dimm_types_mcs[PORTS_PER_MCS][MAX_DIMM_PER_PORT] = {};

    FAPI_TRY( base_module_type(i_target, i_spd_data, o_dimm_type),
              "%s. Failed to find base module type", mss::c_str(i_target) );
    FAPI_TRY( eff_dimm_type(l_mcs, &l_dimm_types_mcs[0][0]),
              "%s. Failed to invoke DIMM type accessor", mss::c_str(i_target));

    l_dimm_types_mcs[l_port_num][l_dimm_num] = o_dimm_type;
    FAPI_TRY( FAPI_ATTR_SET(fapi2::ATTR_EFF_DIMM_TYPE, l_mcs, l_dimm_types_mcs),
              "%s. Failed to set ATTR_EFF_DIMM_TYPE", mss::c_str(i_target));

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief Helper function to set dram gen attribute
/// @param[in] i_target dimm target
/// @param[in] i_spd_data SPD data
/// @return FAPI2_RC_SUCCESS if okay
///
static fapi2::ReturnCode dram_gen_setter(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
        const std::vector<uint8_t>& i_spd_data)
{
    const auto l_port_num = index( find_target<TARGET_TYPE_MCA>(i_target) );
    const auto l_dimm_num = index(i_target);
    const auto l_mcs = mss::find_target<TARGET_TYPE_MCS>(i_target);

    // Get dram generation & set attribute (needed by c_str)
    uint8_t l_dram_gen = 0;
    uint8_t l_dram_gen_mcs[PORTS_PER_MCS][MAX_DIMM_PER_PORT] = {};

    FAPI_TRY( eff_dram_gen(l_mcs, &l_dram_gen_mcs[0][0]),
              "%s. Failed to inboke DRAM gen accesssor", mss::c_str(i_target) );
    FAPI_TRY( dram_device_type(i_target, i_spd_data, l_dram_gen),
              "%s. Failed to find base module type", mss::c_str(i_target) );

    l_dram_gen_mcs[l_port_num][l_dimm_num] = l_dram_gen;

    FAPI_TRY( FAPI_ATTR_SET(fapi2::ATTR_EFF_DRAM_GEN, l_mcs, l_dram_gen_mcs),
              "%s. Failed to set ATTR_EFF_DRAM_GEN", mss::c_str(i_target) );

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief Determines & sets effective config for number of master ranks per dimm
/// @param[in] i_target FAPI2 target
/// @param[in] the SPD cache
/// @return fapi2::FAPI2_RC_SUCCESS if okay
/// @note This is done after the SPD cache is configured so that it can reflect the results of the
/// factory and we don't need to worry about SPD versions. This is expressly different than the dram and dimm setters
///
fapi2::ReturnCode master_ranks_per_dimm_setter(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
        const std::shared_ptr<decoder>& i_pDecoder)
{
    const auto l_mcs = find_target<TARGET_TYPE_MCS>(i_target);
    const auto l_mca = find_target<TARGET_TYPE_MCA>(i_target);

    uint8_t l_decoder_val = 0;
    fapi2::buffer<uint8_t> l_ranks_configed;
    uint8_t l_attrs_master_ranks_per_dimm[PORTS_PER_MCS][MAX_DIMM_PER_PORT] = {};
    uint8_t l_attrs_dimm_ranks_configed[PORTS_PER_MCS][MAX_DIMM_PER_PORT] = {};

    // Get & update MCS attribute
    FAPI_TRY( i_pDecoder->num_package_ranks_per_dimm(l_decoder_val),
              "%s. Failed num_package_ranks_per_dimm()", mss::c_str(i_target) );
    FAPI_TRY(eff_num_master_ranks_per_dimm(l_mcs, &l_attrs_master_ranks_per_dimm[0][0]),
             "%s. Failed eff_num_master_ranks_per_dimm()", mss::c_str(i_target) );
    FAPI_TRY(eff_dimm_ranks_configed(l_mcs, &l_attrs_dimm_ranks_configed[0][0]),
             "%s. Failed eff_dimm_ranks_configed()", mss::c_str(i_target) );

    l_attrs_master_ranks_per_dimm[index(l_mca)][index(i_target)] = l_decoder_val;

    // Set configed ranks. Set the bit representing the master rank configured (0 being left most.) So,
    // a 4R DIMM would be 0b11110000 (0xF0). This is used by PRD.
    FAPI_TRY( l_ranks_configed.setBit(0, l_decoder_val),
              "%s. Failed to setBit", mss::c_str(i_target) );

    l_attrs_dimm_ranks_configed[index(l_mca)][index(i_target)] = l_ranks_configed;

    FAPI_INF( "%s Num Master Ranks %d, DIMM Ranks Configed 0x%x",
              mss::c_str(i_target),
              l_attrs_master_ranks_per_dimm[index(l_mca)][index(i_target)],
              l_attrs_dimm_ranks_configed[index(l_mca)][index(i_target)] );

    FAPI_TRY( FAPI_ATTR_SET(fapi2::ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM, l_mcs, l_attrs_master_ranks_per_dimm),
              "%s. Failed to set ATTR_EFF_NUM_MASTER_RANKS_PER_DIMM", mss::c_str(i_target) );

    FAPI_TRY( FAPI_ATTR_SET(fapi2::ATTR_EFF_DIMM_RANKS_CONFIGED, l_mcs, l_attrs_dimm_ranks_configed),
              "%s. Failed to set ATTR_EFF_DIMM_RANKS_CONFIGED", mss::c_str(i_target) );

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief       Helper function to return RDIMM decoder
/// @param[in]   i_target dimm target
/// @param[in]   i_encoding_rev encoding revision
/// @param[in]   i_additions_rev additions revision
/// @param[in]   i_raw_card raw card reference revision
/// @param[in]   i_spd_data SPD data
/// @param[out]  o_fact_obj shared pointer to the factory object
/// @return      FAPI2_RC_SUCCESS if okay
/// @note        Factory dependent on SPD revision & dimm type
///
static fapi2::ReturnCode rdimm_rev_helper(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
        const uint8_t i_encoding_rev,
        const uint8_t i_additions_rev,
        const rcw_settings i_raw_card,
        const std::vector<uint8_t>& i_spd_data,
        std::shared_ptr<decoder>& o_fact_obj)
{
    // This needs to be updated for added revisions
    constexpr uint64_t HIGHEST_ENCODING_LEVEL = 1;
    constexpr uint64_t HIGHEST_ADDITIONS_LEVEL = 1;

    fapi2::current_err = fapi2::FAPI2_RC_SUCCESS;
    std::shared_ptr<dimm_module_decoder> l_module_decoder;

    // SPD Revision format #.#
    // 1st # = encoding level
    // 2nd # = additions level
    switch(i_encoding_rev)
    {
        // Skipping case 0 since we shouldn't be using pre-production revisions
        case 1:
            switch(i_additions_rev)
            {
                // Rev 1.0
                case 0:
                    // Life starts out at base revision level
                    FAPI_INF( "%s. Creating decoder for RDIMM SPD revision 1.0", mss::c_str(i_target) );
                    l_module_decoder = std::make_shared<ddr4::rdimm::decoder_v1_0>(i_target, i_spd_data);
                    o_fact_obj = std::make_shared<ddr4::decoder_v1_0>( i_target, i_spd_data, l_module_decoder, i_raw_card );
                    break;

                case 1:
                    // Rev 1.1
                    // Changes to both the general section & rdimm section occured
                    FAPI_INF( "%s. Creating decoder for RDIMM SPD revision 1.1", mss::c_str(i_target) );
                    l_module_decoder = std::make_shared<ddr4::rdimm::decoder_v1_1>(i_target, i_spd_data);
                    o_fact_obj = std::make_shared<ddr4::decoder_v1_1>( i_target, i_spd_data, l_module_decoder, i_raw_card );
                    break;

                default:
                    // For additions level retrieved from SPD higher than highest decoded revision level,
                    // we default to be highest decoded additions level because they are backward compatable.
                    // This will need to be updated for every new additions level that is decoded.
                    FAPI_INF( "%s. Unable to create decoder for retrieved SPD RDIMM revision %d.%d",
                              mss::c_str(i_target), i_encoding_rev, i_additions_rev );

                    FAPI_INF("%s. Falling back to highest supported, backward-comptable decoder, "
                             "for SPD RDIMM revision %d.%d",
                             mss::c_str(i_target), HIGHEST_ENCODING_LEVEL, HIGHEST_ADDITIONS_LEVEL );

                    l_module_decoder = std::make_shared<ddr4::rdimm::decoder_v1_1>(i_target, i_spd_data);
                    o_fact_obj = std::make_shared<ddr4::decoder_v1_1>( i_target, i_spd_data, l_module_decoder, i_raw_card );
                    break;

            }//end additions

            break;

        default:
            // For encodings level retrieved from SPD higher than highest decoded revision level,
            // we error out because encoding level changes are NOT backward comptable.
            // Current this means Rev 2.0+ is no supported
            FAPI_TRY( mss::check::spd::invalid_factory_sel(i_target,
                      fapi2::ENUM_ATTR_EFF_DIMM_TYPE_RDIMM,
                      i_encoding_rev,
                      i_additions_rev,
                      "Encoding Level unsupported!"),
                      "%s. Invalid encoding level received: %d",
                      mss::c_str(i_target), i_encoding_rev);

            break;
    }// end encodings

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief       Helper function to return LRDIMM decoder
/// @param[in]   i_target dimm target
/// @param[in]   i_encoding_rev encoding revision
/// @param[in]   i_additions_rev additions revision
/// @param[in]   i_raw_card raw card reference revision
/// @param[in]   i_spd_data SPD data
/// @param[out]  o_fact_obj shared pointer to the factory object
/// @return      FAPI2_RC_SUCCESS if okay
/// @note        Factory dependent on SPD revision & dimm type
///
static fapi2::ReturnCode lrdimm_rev_helper(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
        const uint8_t i_encoding_rev,
        const uint8_t i_additions_rev,
        const rcw_settings i_raw_card,
        const std::vector<uint8_t>& i_spd_data,
        std::shared_ptr<decoder>& o_fact_obj)
{
    fapi2::current_err = fapi2::FAPI2_RC_SUCCESS;
    std::shared_ptr<dimm_module_decoder> l_module_decoder;

    // This needs to be updated for added revisions
    constexpr uint64_t HIGHEST_ENCODING_LEVEL = 2;
    constexpr uint64_t HIGHEST_ADDITIONS_LEVEL = 1;

    // SPD Revision format #.#
    // 1st # = encoding level
    // 2nd # = additions level
    switch(i_encoding_rev)
    {
        // Skipping case 0 since we shouldn't be using pre-production revisions
        case 1:
            switch(i_additions_rev)
            {
                // Rev 1.0
                case 0:
                    // Life starts out at base revision level
                    FAPI_INF( "%s. Creating decoder for LRDIMM SPD revision 1.0", mss::c_str(i_target) );
                    l_module_decoder = std::make_shared<ddr4::lrdimm::decoder_v1_0>(i_target, i_spd_data);
                    o_fact_obj = std::make_shared<decoder>( i_target, i_spd_data, l_module_decoder, i_raw_card );
                    break;

                case 1:
                    // Rev 1.1
                    // Changes to both the general section & lrdimm section occured
                    FAPI_INF( "%s. Creating decoder for LRDIMM SPD revision 1.1", mss::c_str(i_target) );
                    l_module_decoder = std::make_shared<ddr4::lrdimm::decoder_v1_1>(i_target, i_spd_data);
                    o_fact_obj = std::make_shared<ddr4::decoder_v1_1>( i_target, i_spd_data, l_module_decoder, i_raw_card );
                    break;

                case 2:
                    // Rev 1.2
                    // Changes lrdimm section occured
                    // General section remained the same
                    FAPI_INF( "%s. Creating decoder for LRDIMM SPD revision 1.2", mss::c_str(i_target) );
                    l_module_decoder = std::make_shared<ddr4::lrdimm::decoder_v1_2>(i_target, i_spd_data);
                    o_fact_obj = std::make_shared<ddr4::decoder_v1_1>( i_target, i_spd_data, l_module_decoder, i_raw_card );
                    break;

                default:
                    // For additions level retrieved from SPD higher than highest decoded revision level,
                    // we default to be highest decoded additions level because they are backward compatable.
                    // This will need to be updated for every new additions level that is decoded.
                    FAPI_INF( "%s. Unable to create decoder for retrieved SPD LRDIMM revision %d.%d",
                              mss::c_str(i_target), i_encoding_rev, i_additions_rev );

                    FAPI_INF("%s. Falling back to highest supported, backward-comptable decoder, "
                             "for SPD LRDIMM revision %d.%d",
                             mss::c_str(i_target), HIGHEST_ENCODING_LEVEL, HIGHEST_ADDITIONS_LEVEL );

                    l_module_decoder = std::make_shared<ddr4::lrdimm::decoder_v1_2>(i_target, i_spd_data);
                    o_fact_obj = std::make_shared<ddr4::decoder_v1_1>( i_target, i_spd_data, l_module_decoder, i_raw_card );
                    break;

            }//end additions

            break;

        default:
            // For encodings level retrieved from SPD higher than highest decoded revision level,
            // we error out because encoding level changes are NOT backward comptable.
            // Currently this means Rev 2.0+ is not supported
            FAPI_TRY( mss::check::spd::invalid_factory_sel(i_target,
                      fapi2::ENUM_ATTR_EFF_DIMM_TYPE_LRDIMM,
                      i_encoding_rev,
                      i_additions_rev,
                      "Encoding Level unsupported!"),
                      "%s. Invalid encoding level received: %d",
                      mss::c_str(i_target), i_encoding_rev);
            break;
    }// end encodings

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief Retrieve current raw card settings
/// based on dimm type and raw card reference rev
/// @param[in] i_target dimm target
/// @param[in] i_spd_data SPD data
/// @param[out] o_raw_card raw card settings
/// @return FAPI2_RC_SUCCESS if okay
///
fapi2::ReturnCode raw_card_factory(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
                                   const std::vector<uint8_t>& i_spd_data,
                                   rcw_settings& o_raw_card)
{
    uint8_t l_dimm_type = 0;
    uint8_t l_ref_raw_card_rev = 0;

    // Lets find out what raw card we are and grab the right
    // raw card settings
    FAPI_TRY( mss::eff_dimm_type(i_target, l_dimm_type) );
    FAPI_TRY( reference_raw_card(i_target, i_spd_data, l_ref_raw_card_rev) );

    FAPI_INF( "Retrieved dimm_type: %d, raw card reference: 0x%lx from SPD",
              l_dimm_type, l_ref_raw_card_rev);

    switch(l_dimm_type)
    {
        case fapi2::ENUM_ATTR_EFF_DIMM_TYPE_RDIMM:

            FAPI_ASSERT( find_value_from_key( mss::rdimm::RAW_CARDS, l_ref_raw_card_rev, o_raw_card),
                         fapi2::MSS_INVALID_RAW_CARD()
                         .set_DIMM_TYPE(l_dimm_type)
                         .set_RAW_CARD_REV(l_ref_raw_card_rev)
                         .set_DIMM_TARGET(i_target),
                         "Invalid reference raw card recieved for RDIMM: %d for %s",
                         l_ref_raw_card_rev,
                         mss::c_str(i_target) );
            break;

        case fapi2::ENUM_ATTR_EFF_DIMM_TYPE_LRDIMM:

            FAPI_ASSERT( find_value_from_key( mss::lrdimm::RAW_CARDS, l_ref_raw_card_rev, o_raw_card),
                         fapi2::MSS_INVALID_RAW_CARD()
                         .set_DIMM_TYPE(l_dimm_type)
                         .set_RAW_CARD_REV(l_ref_raw_card_rev)
                         .set_DIMM_TARGET(i_target),
                         "Invalid reference raw card recieved for LRDIMM: %d for %s",
                         l_ref_raw_card_rev,
                         mss::c_str(i_target));
            break;

        default:

            FAPI_ASSERT( false,
                         fapi2::MSS_INVALID_DIMM_TYPE()
                         .set_DIMM_TYPE(l_dimm_type)
                         .set_TARGET(i_target),
                         "Recieved invalid dimm type: %d for %s",
                         l_dimm_type, mss::c_str(i_target) );
            break;
    }

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief       Object factory to select correct decoder
/// @param[in]   i_target dimm target
/// @param[in]   i_spd_data SPD data
/// @param[out]  o_fact_obj shared pointer to the factory object
/// @return      FAPI2_RC_SUCCESS if okay
/// @note        Factory dependent on SPD revision & dimm type
///
fapi2::ReturnCode factory(const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
                          const std::vector<uint8_t>& i_spd_data,
                          std::shared_ptr<decoder>& o_fact_obj)
{
    if( i_spd_data.empty() )
    {
        // This won't work with no data
        FAPI_ERR( "%s. SPD vector of data is empty! Factory requires valid SPD data.", mss::c_str(i_target) );
        return fapi2::FAPI2_RC_INVALID_PARAMETER;
    }

    uint8_t l_dimm_type = 0;
    uint8_t l_encoding_rev = 0;
    uint8_t l_additions_rev = 0;
    rcw_settings l_raw_card;

    // Attribute setting needed by mss::c_str() which is used in
    // the SPD decoder for debugging help
    FAPI_TRY( dimm_type_setter(i_target, i_spd_data, l_dimm_type),
              "%s. Failed to set DIMM type", mss::c_str(i_target) );
    FAPI_TRY( dram_gen_setter(i_target, i_spd_data),
              "%s. Failed to set DRAM generation", mss::c_str(i_target) );
    FAPI_TRY( raw_card_factory(i_target, i_spd_data, l_raw_card),
              "%s. Failed raw_card_factory()", mss::c_str(i_target) );

    // Get revision levels to figure out what SPD version we are
    FAPI_TRY( rev_encoding_level(i_target, i_spd_data, l_encoding_rev),
              "%s. Failed to decode encoding level", mss::c_str(i_target) );
    FAPI_TRY( rev_additions_level(i_target, i_spd_data,  l_additions_rev),
              "%s. Failed to decode additons level", mss::c_str(i_target) );

    // Get decoder object needed for current dimm type and spd rev
    switch(l_dimm_type)
    {
        // Each dimm type rev is independent
        case fapi2::ENUM_ATTR_EFF_DIMM_TYPE_RDIMM:
            FAPI_TRY( rdimm_rev_helper(i_target,
                                       l_encoding_rev,
                                       l_additions_rev,
                                       l_raw_card,
                                       i_spd_data,
                                       o_fact_obj),
                      "%s. Failed to decode SPD revision for RDIMM, "
                      "encoding rev: %d, additions rev: %d",
                      mss::c_str(i_target), l_encoding_rev, l_additions_rev );
            break;

        // Each dimm type rev is independent
        case fapi2::ENUM_ATTR_EFF_DIMM_TYPE_LRDIMM:
            FAPI_TRY( lrdimm_rev_helper(i_target,
                                        l_encoding_rev,
                                        l_additions_rev,
                                        l_raw_card,
                                        i_spd_data,
                                        o_fact_obj),
                      "%s. Failed to decode SPD revision for LRDIMM, "
                      "encoding rev: %d, additions rev: %d",
                      mss::c_str(i_target), l_encoding_rev, l_additions_rev);
            break;

        default:
            FAPI_TRY( mss::check::spd::invalid_factory_sel(i_target,
                      l_dimm_type,
                      l_encoding_rev,
                      l_additions_rev,
                      "DIMM Type unsupported!") );
            break;

    } // end dimm type

    FAPI_INF( "%s: Decoder created for DIMM type: %d, SPD revision %d.%d",
              mss::c_str(i_target),
              l_dimm_type,
              l_encoding_rev,
              l_additions_rev );

fapi_try_exit:
    return fapi2::current_err;
}

///
/// @brief       Creates factory object & SPD data caches
/// @param[in]   i_target the dimm target
/// @param[out]  o_factory_caches vector of factory objects
/// @param[in]   i_pDecoder custom decoder to populate cache (nullptr default)
/// @return      FAPI2_RC_SUCCESS if okay
/// @note        This specialization is suited for creating a cache with custom
///              SPD data (e.g. testing custom SPD).
///
template<>
fapi2::ReturnCode populate_decoder_caches( const fapi2::Target<TARGET_TYPE_DIMM>& i_target,
        std::vector< std::shared_ptr<decoder> >& o_factory_caches,
        const std::shared_ptr<decoder>& i_pDecoder)
{
    if(i_pDecoder == nullptr)
    {
        // This won't work w/a null parameter
        FAPI_ERR("%s. Received decoder is NULL!", mss::c_str(i_target) );
        return fapi2::FAPI2_RC_INVALID_PARAMETER;
    }

    // Custom decoder provided (usually done for testing)
    // Populate custom spd caches maps one dimm at a time
    o_factory_caches.push_back( i_pDecoder );

    // Populate some of the DIMM attributes early. This allows the following code to make
    // decisions based on DIMM information. Expressly done after the factory has decided on the SPD version
    FAPI_TRY( master_ranks_per_dimm_setter(i_target, i_pDecoder),
              "%s. Failed master_ranks_per_dimm_setter()", mss::c_str(i_target) );

fapi_try_exit:
    return fapi2::current_err;
}

}// spd
}// mss