questions about DMA transmition

hi,gurus

I have try lots of times ,but always failed,so I hope someone can give me help~

the self-made SOPC component is connected to read master port of DMA, SDRAM is connected to write master port of DMA.

the setl-made component is connected to avalon bus as a slave interface.when I use "IORD"to read the component,it is right,but when I connect is to DMA,DMA transmits failed~

if((rx= alt_avalon_dma_prepare(rxchan,rx_buffer,1024,done_t,NULL))<0)

{

printf("rxchan receive failed.reason: %d",rx);

exit(1);

}

dma_prepare always failed, if the self-made component has some problems (the component consist of a FIFO which connected to avalon through slave port )??

The NiosII software code is attached

the pogrammme is very urge,and there is nobody around me can give me advise,so I hope you gurus can give me some hints~

thanks very much~~