stream transfer between uart and onchiop memory

Hello:

I use the DMA controler to connect the data rom and Uart and use it to connect the instructing ram and data ram.But the uart can't receive the data.My code is below:

IOWR_ALTERA_AVALON_DMA_STATUS(DMA_BASE,0);

IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_BASE,0);

IOWR_ALTERA_AVALON_DMA_LENGTH(DMA_BASE,0xff);

IOWR_ALTERA_AVALON_DMA_RADDRESS(DMA_BASE,(int)buffer);

IOWR_ALTERA_AVALON_DMA_WADDRESS(DMA_BASE,UART_BASE);

IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_BASE,ALTERA_AVALON_DMA_CONTROL_GO_MSK|ALTERA_AVALON_DMA_CONTROL_LEEN_MSK|ALTERA_AVALON_DMA_CONTROL_WCON_MSK|ALTERA_AVALON_DMA_CONTROL_BYTE_MSK);

Have problem?

while((IORD_ALTERA_AVALON_DMA_STATUS(DMA_BASE)& ALTERA_AVALON_DMA_STATUS_BUSY_MSK)!=0);