IWR6843: Injecting a test radar cube into DSS memory

I am trying to inject a recorded radar cube into the DSS processing chain in order to debug the DSP AoA algorithm. It isn't working -- it appears that data is not initialized and I get all zeros as output. I am wondering what I am doing wrong.

In dss_main following the example in the sdk_user_guide, I have:

#define TEST_RADAR_CUBE_SIZE 12288
#define TEST_RADAR_CUBE_ALIGNMENT 8


/*! L3 RAM buffer for object detection DPC */
uint8_t gMmwL3[SOC_L3RAM_SIZE - TEST_RADAR_CUBE_SIZE*sizeof(cmplx16ImRe_t) - TEST_RADAR_CUBE_ALIGNMENT];
#pragma DATA_SECTION(gMmwL3, ".l3ram");


#pragma DATA_SECTION(testRadarCube, ".l3data_testradarcube");
#pragma DATA_ALIGN(testRadarCube, TEST_RADAR_CUBE_ALIGNMENT);
#include <ti/datapath/dpc/dpu/dopplerproc/include/testradarcube.h>

where testradarcube.h has the definition:

const cmplx16ImRe_t __attribute__((used)) testRadarCube[TEST_RADAR_CUBE_SIZE] = {
{96, -136}, {-179, 229}, {144, -169}, {10, 87}, {-66, -70},
{11, 41}, {1, -2}, {55, -15}, {-97, 16}, {82, -9},
{-39, 2}, {6, -7}, {10, 15}, {-7, -7}, {-6, -5}, ... }

In dopplerprocdsp.c, I have

#define TEST_RADAR_CUBE_SIZE 12288
extern const cmplx16ImRe_t testRadarCube[TEST_RADAR_CUBE_SIZE];

int32_t DPU_DopplerProcDSP_process
(
    DPU_DopplerProcDSP_Handle    handle,
    DPU_DopplerProcDSP_OutParams *outParams
)
{
    DPU_DopplerProcDSP_Obj *obj;
    DPU_DopplerProcDSP_Config *cfg;
    uint16_t rxAntIdx, rangeIdx, txAntIdx; 
    uint16_t nextTransferRxIdx, nextTransferRangeIdx, nextTransferTxIdx; 
    uint16_t rxAntIdxBPMPreviousBuffer, txAntIdxBPMPreviousBuffer;
    uint32_t nextTransferIdx, waitingTime, pingPongIdx;
    volatile uint32_t startTime;
    volatile uint32_t startTimeWait;
    int32_t  *fftOutPtr;
    int32_t  retVal;
    uint8_t  channel;
    cmplx16ImRe_t  *inpDoppFftBuf;
    cmplx16ImRe_t  *radarCubeBase;
    cmplx32ReIm_t  *windowingOutBuf;

    retVal = 0;    
    waitingTime = 0;
    obj = (DPU_DopplerProcDSP_Obj *)handle;
    
    if (obj == NULL)
    {
        retVal = DPU_DOPPLERPROCDSP_EINVAL;
        goto exit;
    }    
    
    if(obj->inProgress == true)
    {
        retVal = DPU_DOPPLERPROCDSP_EINPROGRESS;
        goto exit;
    }
    else
    {
        obj->inProgress = true;
    }

    startTime = Cycleprofiler_getTimeStamp();


    radarCubeBase = (cmplx16ImRe_t *)obj->cfg.hwRes.radarCube.data; 
    cfg =  &obj->cfg;

    dspDpu_setRadarCubeDSP(handle);

    //rest of file is as normal
    ...  

}

The function dspDpu_setRadarCubeDSP looks like this:

#pragma FUNCTION_OPTIONS(dspDpu_setRadarCubeDSP, "-O0")
void dspDpu_setRadarCubeDSP( DPU_DopplerProcDSP_Handle  handle )
{
    size_t testRadarCubeSize;
    DPU_DopplerProcDSP_Obj *obj;                
    volatile cmplx16ImRe_t  *radarCubeBase;

    // Setup
    obj = (DPU_DopplerProcDSP_Obj *)handle;
    radarCubeBase = (cmplx16ImRe_t *)obj->cfg.hwRes.radarCube.data; 


    // Copy over
    testRadarCubeSize = sizeof(testRadarCube); // Size of testRadarCube array in bytes
    memcpy((void*)radarCubeBase, (void*)testRadarCube, testRadarCubeSize);

    return; 
}

My mmw_dss_linker.cmd file looks like

/*----------------------------------------------------------------------------*/
/* Linker Settings                                                            */
--retain="*(.intvecs)"

/*----------------------------------------------------------------------------*/
/* Section Configuration                                                      */
SECTIONS
{
    systemHeap : {} >> L2SRAM_UMAP0 | L2SRAM_UMAP1
    .l3ram: {} >> L3SRAM
    .l3data_testradarcube :
    {
        *(.l3data_testradarcube)
    } load = L3SRAM PAGE 0 (HIGH)
    .dpc_l1Heap  : { } > L1DSRAM
    .dpc_l2Heap: { } >> L2SRAM_UMAP0 | L2SRAM_UMAP1
    .demoSharedMem: { } >> HSRAM
}
/*----------------------------------------------------------------------------*/

And the map file shows the test cube:

MEMORY CONFIGURATION

         name            origin    length      used     unused   attr    fill
----------------------  --------  ---------  --------  --------  ----  --------
PAGE 0:
  ...
  L3SRAM                20000000   000c0000  000bfff8  00000008  RWIX
  ...
  
  
  SEGMENT ALLOCATION MAP

run origin  load origin   length   init length attrs members
----------  ----------- ---------- ----------- ----- -------
  ...
  20000000    20000000    000b3ff8   00000000    rw- .l3ram
200b4000    200b4000    0000c000   0000c000    r--
  200b4000    200b4000    0000c000   0000c000    r-- .l3data_testradarcube
  ...

SECTION ALLOCATION MAP

 output                                  attributes/
section   page    origin      length       input sections
--------  ----  ----------  ----------   ----------------
  ...

.l3data_testradarcube 
*          0    200b4000    0000c000     
                  200b4000    0000c000     dss_main.oe674 (.l3data_testradarcube)
  ...


GLOBAL SYMBOLS: SORTED BY Symbol Address 

address   name                                                         
-------   ----                    
...       ...
20000000  gMmwL3                                                       
200b4000  testRadarCube                                                
21080000  gHSRAM       
...       ...

It all compiles just fine. So I think the memcpy should work -- but when I output the radar cube, I get all zeros. Why? What am I doing wrong?