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hi ,
my problem has been resolved ,the uart ip has "end of packet"selection,if you use it,it sets zero as the end character,so if your characters to be transferred include zero,the uart will stop the transfer when it meets zero .:)
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Hi,
Currently I got problem with DMA as Rx channel :(. What I'm trying to don now is I want to verify whether the DMA can handle data transfer from a PIO to memory. So in my verification system here, I'm doing a loopback test by adding two PIOs in my SOPC system which functions as the data transmitter (the PIO's name is PIO_DUMY_OUTPUT) and receiver (the PIO's name is PIO_DATA_8BIT), respectively. I connected those PIO's in my verilog code.
Here is my code :
volatile static int txrx_done = 0;
// callback function when DMA transfer done
static void txrxDone (void * handle, void * data)
{
txrx_done = 1;
}
void initMEM(int base_addr, int len, int data)
{
int i;
for (i=0; i<len; i++)
{
IOWR_8DIRECT(base_addr+i, 0, 33);
}
}
// peripheral - memory transfer 1
void pio_transfer()
{
int rc, i, mode;
int dma_len = 0x25;
alt_dma_rxchan rxchan;
void * rx_buffer = (void*) DDR3_TOP_BASE;
txrx_done = 0;
// -------------------------------------------------------------------------------
printf("testing peripheral to memory dma operation\n");
initMEM(DDR3_TOP_BASE,dma_len,3);
printf("content of the memory content before DMA operation : \n");
for (i=0; i<dma_len; i++)
{
printf("%d : %x\n", i, IORD_8DIRECT(DDR3_TOP_BASE,i));
}
// -------------------------------------------------------------------------------
if((rxchan = alt_dma_rxchan_open("/dev/dma_data_8bit")) == NULL)
{
printf("Failed to open receive channel\n");
exit(1);
}
// -------------------------------------------------------------------------------
if(alt_dma_rxchan_ioctl(rxchan,ALT_DMA_SET_MODE_8,NULL)<0)
{
exit(1);
}
printf("debug0 \n");
check_dma();
if(alt_dma_rxchan_ioctl(rxchan,ALT_DMA_RX_ONLY_ON, (void*) PIO_DATA_8BIT_BASE)<0)
{
exit(1);
}
// -------------------------------------------------------------------------------
printf("debug1 \n");
if((rc = alt_dma_rxchan_prepare(rxchan, rx_buffer, dma_len, NULL, NULL))<0)
{
printf("Failed to post receive request, reason = %i\n", rc);
exit(1);
}
// -------------------------------------------------------------------------------
printf("PIO : generate, transmit, and receive the dummy data\n");
for (i=0; i<dma_len; i++)
{
IOWR_ALTERA_AVALON_PIO_DATA(PIO_DUMY_OUTPUT_BASE, 3*i+2);
printf("PIO : receiving dummy data : %d - %d\n",IORD_ALTERA_AVALON_PIO_DATA(PIO_DATA_8BIT_BASE), txrx_done);
}
IOWR_ALTERA_AVALON_PIO_DATA(PIO_DUMY_OUTPUT_BASE, '\0'); //write end-of-packet character
// -------------------------------------------------------------------------------
printf("debug2 \n");
check_dma();
printf("wait DMA transfer is completed\n");
//while(!txrx_done);
//alt_dma_rxchan_close (rxchan);
printf("Transfer is success\n");
check_dma();
// -------------------------------------------------------------------------------
printf("content of the memory DDR3 content after DMA operation : \n");
for (i=0; i<dma_len; i++)
{
printf("%d : %x\n", i, IORD_8DIRECT(DDR3_TOP_BASE,i));
}
// -------------------------------------------------------------------------------
}
And here is the result :
content of the memory content before DMA operation :
0 : 21
1 : 21
2 : 21
3 : 21
4 : 21
5 : 21
6 : 21
7 : 21
8 : 21
9 : 21
10 : 21
11 : 21
12 : 21
13 : 21
14 : 21
15 : 21
16 : 21
17 : 21
18 : 21
19 : 21
20 : 21
21 : 21
22 : 21
23 : 21
24 : 21
25 : 21
26 : 21
27 : 21
28 : 21
29 : 21
30 : 21
31 : 21
32 : 21
33 : 21
34 : 21
35 : 21
36 : 21
PIO : generate, transmit, and receive the dummy data
PIO : receiving dummy data : 2 - 0
PIO : receiving dummy data : 5 - 0
PIO : receiving dummy data : 8 - 0
PIO : receiving dummy data : 11 - 0
PIO : receiving dummy data : 14 - 0
PIO : receiving dummy data : 17 - 0
PIO : receiving dummy data : 20 - 0
PIO : receiving dummy data : 23 - 0
PIO : receiving dummy data : 26 - 0
PIO : receiving dummy data : 29 - 0
PIO : receiving dummy data : 32 - 0
PIO : receiving dummy data : 35 - 0
PIO : receiving dummy data : 38 - 0
PIO : receiving dummy data : 41 - 0
PIO : receiving dummy data : 44 - 0
PIO : receiving dummy data : 47 - 0
PIO : receiving dummy data : 50 - 0
PIO : receiving dummy data : 53 - 0
PIO : receiving dummy data : 56 - 0
PIO : receiving dummy data : 59 - 0
PIO : receiving dummy data : 62 - 0
PIO : receiving dummy data : 65 - 0
PIO : receiving dummy data : 68 - 0
PIO : receiving dummy data : 71 - 0
PIO : receiving dummy data : 74 - 0
PIO : receiving dummy data : 77 - 0
PIO : receiving dummy data : 80 - 0
PIO : receiving dummy data : 83 - 0
PIO : receiving dummy data : 86 - 0
PIO : receiving dummy data : 89 - 0
PIO : receiving dummy data : 92 - 0
PIO : receiving dummy data : 95 - 0
PIO : receiving dummy data : 98 - 0
PIO : receiving dummy data : 101 - 0
PIO : receiving dummy data : 104 - 0
PIO : receiving dummy data : 107 - 0
PIO : receiving dummy data : 110 - 0
content of the memory DDR3 content after DMA operation :
0 : 0
1 : 0
2 : 0
3 : 0
4 : 0
5 : 0
6 : 0
7 : 0
8 : 0
9 : 0
10 : 0
11 : 0
12 : 0
13 : 0
14 : 0
15 : 0
16 : 0
17 : 0
18 : 0
19 : 0
20 : 0
21 : 0
22 : 0
23 : 0
So anyone can tell me why the DMA can't write correctly the data that received by PIO_DATA_8BIT to DDR3 ? Is my loopback test wrong? Is it possible to handle data transfer from a PIO to memory like what I'm doing? :confused:
Thanks before, I really appreciate any comments and help :)
Honored Contributor
