DMA Transfer problem

Hi,

I am trying to do a simple DMA mem to mem transfer as per the "Chap24: DMA controller core " example.

I have been at this for almost a week now and it is still not working for me. Can you please help me.

The dma transfer is getting stuck in the "while(!txrx_done)" loop. I am not getting any error messages.

Here is the status of my registers just before it enters the "while loop".

readaddress =800000, writeaddress =801000, length =80, status =2, control =fc

Here are the details of my setup:

I am using the DE2 board.

First in Qsys: DMA Controller

DMA Read Master -> SDRAM Controller slave

DMA Write Master -> SDRAM Controller slave

DMA Control-port Slave-> CPU Data Master

niosii code:

staticvolatileint txrx_done = 0;

static

void txrxdone(void * handle, void * data)

{

txrx_done = 1;

}

init code:

alt_dma_txchan txchan;

alt_dma_rxchan rxchan;

alt_u32* tx_data = (alt_u32*)0x800000;

alt_u32* rx_buffer = (alt_u32*)(0x801000);

// Create the transmit channel

if ((txchan = alt_dma_txchan_open("/dev/dma_0")) == NULL)

{

printf ("Failed to open transmit channel\n");

exit (1);

}

// Create the receive channel

if ((rxchan = alt_dma_rxchan_open("/dev/dma_0")) == NULL)

{

printf ("Failed to open receive channel\n");

exit (1);

}

setting up transfer:

printf("Setting up DMA\n");

// Post the transmit request

if ((rc1 = alt_dma_txchan_send (txchan,

tx_data,

128,

NULL,

NULL)) < 0)

{

printf ("Failed to post transmit request, reason = %i\n", rc1);

exit (1);

}

&#12288;

if ((rc1 = alt_dma_rxchan_prepare (rxchan,

rx_buffer,

128,

txrxDone,

NULL)) < 0)

{

printf ("Failed to post read request, reason = %i\n", rc1);

exit (1);

}

while (!txrx_done);

printf ("Transfer successful!\n");

Please help!