help on using NIOS II DMA in the design

[Altera_Forum]

Hi, 

 I am trying use the DMA example code as it is given in the nios 2 s/w handbook,   the code is as given below,   #include <stdio.h># include <stdlib.h># include "sys/alt_dma.h"# include "system.h" static volatile int rx_done = 0; /* * Callback function that obtains notification that the data * is received. */ static void done (void* handle, void* data) { rx_done++; } /* * */ int main (int argc, char* argv[], char* envp[]) { int rc; alt_dma_txchan txchan; alt_dma_rxchan rxchan; void* tx_data = (void*) 0x901000; /* pointer to data to send */ void* rx_buffer = (void*) 0x902000; /* pointer to rx buffer */ /* 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); } /* Post the transmit request */ if ((rc = alt_dma_txchan_send (txchan, tx_data, 128, NULL, NULL)) < 0) { printf ("Failed to post transmit request, reason = %i\n", rc); exit (1); } /* Post the receive request */ if ((rc = alt_dma_rxchan_prepare (rxchan, rx_buffer, 128, done, NULL)) < 0) { printf ("Failed to post read request, reason = %i\n", rc); exit (1); } /* Post the receive request */ if ((rc = alt_dma_rxchan_prepare (rxchan, rx_buffer, 128, done, NULL)) < 0) { printf ("Failed to post read request, reason = %i\n", rc); exit (1); } /* wait for transfer to complete */ while (!rx_done); printf ("Transfer successful!\n"); return 0; }   But code is exiting, with an error ( Failed to open transmit channel ).   I want to understand, where am I doing worng. 

[Altera_Forum]

Does your SOPC system include a DMA controller called dma_0 ?

[Altera_Forum]

yes, dma_0 module is included in the sopc. how the dma should be configured in sopc to make use of the HAL API's.

[Altera_Forum]

Are you sure the component is a simple DMA and not a SGDMA? Could you show a printscreen of your SOPC system?