MCF5329 - Using the Message Digest Hardware Accelerator (MDHA)

[TallGuy]

Hi all,

We're trying to use the MDHA to generate an SHA-1 hash from some data we have in memory.
The first block generates the right hash, but more blocks get us a wrong result.

The code we are using:

int main()
{
    int     iRetVal = 0;
    uint32  pu32TestData[32];
    uint32 *pu32HeaderPtr;
    uint32  u32HeaderSize;
    uint32  u32TotalBytes;
    uint8   u8Counter;
    uint32  u32BytesInFifo;

    uint32  u32h0;
    uint32  u32h1;
    uint32  u32h2;
    uint32  u32h3;
    uint32  u32h4;

    memset(pu32TestData, 0x0, 256);
       
    /*
     * Start initializing the MDHA (the hardware module that calculates the
     * hash
     */
   
    /* Reset the MDHA */
    MCF_MDHA_MDCMR = MCF_MDHA_MDCMR_SWR;
   
    while ((MCF_MDHA_MDSR & MCF_MDHA_MDSR_RD) == 0)
    {
        /* Wait until the reset completed */
    }

    /* The first 4 calculations no DMA and no interrupts are used */
    MCF_MDHA_MDCR = MCF_MDHA_MDCR_DMAL(1) | MCF_MDHA_MDCR_ENDIAN;
   
    /* Initialise the SHA algorithm's starting registers */
    MCF_MDHA_MDMR = MCF_MDHA_MDMR_INIT | MCF_MDHA_MDMR_PDATA;

    u32HeaderSize = 68;
    u32TotalBytes = 0;
    pu32HeaderPtr = pu32TestData;
   
    while (u32HeaderSize > 0)
    {
        /* Now fill the FIFO with the first 16 uint32's */
        u8Counter = 0;
        u32BytesInFifo = 0;

        while ((u8Counter  16) && u32HeaderSize > 3)
        {
            MCF_MDHA_MDIN = *pu32HeaderPtr++;
            u32HeaderSize -= 4;
            u32BytesInFifo += 4;
            u8Counter++;
        }
       
        if ((u8Counter  16) && (u32HeaderSize > 0))
        {
            MCF_MDHA_MDIN = *pu32HeaderPtr++;
            u32BytesInFifo += (uint8)u32HeaderSize;
            u32HeaderSize = 0;
        }
       
        /* Fifo Filled */
        MCF_MDHA_MDDSR = u32BytesInFifo;
       
        /* GO!!!!! */
        MCF_MDHA_MDCMR = MCF_MDHA_MDCMR_GO;
       
        /* Now keep polling until the hash is calculated */
        while ((MCF_MDHA_MDSR & MCF_MDHA_MDSR_INT) != 1)
        {
            /*
             * For the time being, do nothing
             */
        }
       
        if ((MCF_MDHA_MDSR & MCF_MDHA_MDSR_ERR) != 0)
        {
            printf("An error occurred generating the SHA-1 hash\n\r");
            iRetVal = -1;
            u32TotalBytes = 0;
        }
        else if ((MCF_MDHA_MDSR & MCF_MDHA_MDSR_DONE) != 0)
        {
            u32TotalBytes += u32BytesInFifo;

            if (u32HeaderSize == 0)
            {
                u32h0 = MCF_MDHA_MDA0;
                u32h1 = MCF_MDHA_MDB0;
                u32h2 = MCF_MDHA_MDC0;
                u32h3 = MCF_MDHA_MDD0;
                u32h4 = MCF_MDHA_MDE0;

                if ((u32h0 == 0x46fe3f0a) &&
                    (u32h1 == 0x75b18d40) &&
                    (u32h2 == 0x6d86aca0) &&
                    (u32h3 == 0xed37bb70) &&
                    (u32h4 == 0x6ed8246b))
                {
                    printf("HASH OK\n\r");
                }
                else
                {
                    printf("HASH INCORRECT\n\r");
                }
            }
            else
            {
                MCF_MDHA_MDCMR = MCF_MDHA_MDCMR_CI;
            }
        }
    }
   
    return iRetVal;
}

If anyone can tell us what we are doing wrong, or if anyone can post some (working) example code (no matter how simple), that would be great.

Regards,

Bas Vermeulen

[taigbr]

Hi Bas,
I don't know if you are still interested in it, but I had a similar problem with MD5 and MDHA.
The trick was to first set MDDSR and then fill the fifo with data. Wait for IFL to clear.
Loop the above until all data is processed. Then give the GO cmd and wait for DONE/INT.
Read the result.
For example:

MDDSR=64 // 64 bytes to come
fill fifo with 16 longwords
wait for IFL==0

MDDSR=64 // 64 bytes to come
fill fifo with 16 longwords
wait for IFL==0

....

GO
wait for DONE

Regards,
Georg