IOWR and direct adress access

/* Here is my test code. To Test DMA from Memory -> UART

some of them cames from this forum.

In The Terminal in My PC, I can see the followed data received

=========================================

0x68 0x65 0x6c 0x6c 0x6f 0x20 0x77 0x6f 0x72 0x6c 0x64 0x0a

0x30

0x31

0x32

0x33

=========================================

the first line is the "hello world"

then i received 4 data send by IOWR macro

after that, nothing received,even NULL.

before DMA,i flush all cache,but nothing changed.

the Timer is running,that means the dma transmit complete,

but i do not know why nothing out from UART.

*/

# include "system.h"# include <stdio.h># include "altera_avalon_pio_regs.h"# include "altera_avalon_timer_regs.h"# include "sys/alt_dma.h"# include "altera_avalon_dma_regs.h"# include "alt_types.h"

volatile alt_u8 count;

static volatile int rx_done = 0;

alt_u8 buffer[16] __attribute__((section(".onchip_ram")));

static void done (void* handle, void* data)

{

rx_done++;

}

void delay(void)

{

volatile int i;

i=0;

while (i<400000) i++;

}

static void handle_Timer0_interrupts(void* context, alt_u32 id)

{

alt_u8 a;

volatile alt_u8 *countptr = (volatile alt_u8 *)context;

IOWR_ALTERA_AVALON_TIMER_STATUS(TIMER_0_BASE, 0);//?TO??

a = *countptr;

a=a<<1;

if (a == 0x10) a=1;

*countptr=a;

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, a);

}

void startTimer(void)

{

count=1;

alt_irq_register(TIMER_0_IRQ, (void *)&count, handle_Timer0_interrupts);

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, 0);

IOWR_ALTERA_AVALON_TIMER_CONTROL(TIMER_0_BASE, 7);

}

int main (void)

{

int rc;

alt_dma_txchan txchan;

FILE *uart;

uart = fopen("/dev/uart0","w");

if(uart==NULL){

}else{

char *str="hello world\n";

fprintf(uart,str);

}

delay();

buffer[0]=0x30; //&#39;0&#39;

buffer[1]=0x31; //&#39;1&#39;

buffer[2]=0x32; //&#39;2&#39;

buffer[3]=0x33; //&#39;3&#39;

IOWR(UART0_BASE,1,buffer[0]);

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, 1);

delay();

IOWR(UART0_BASE,1,buffer[1]);

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, 2);

delay();

IOWR(UART0_BASE,1,buffer[2]);

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, 4);

delay();

IOWR(UART0_BASE,1,buffer[3]);

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, 8);

delay();

void* tx_data = (void*) &buffer[0]; /* pointer to data to send */

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, 1);

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

{

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, 2);

exit (1);

}

alt_dma_txchan_ioctl(txchan,ALT_DMA_SET_MODE_8,NULL);

alt_dma_txchan_ioctl(txchan,ALT_DMA_RX_STREAM_ON,(void*)UART0_BASE+1);

alt_dcache_flush_all();

alt_icache_flush_all();

if ((rc = alt_dma_txchan_send (txchan,tx_data,4,done,NULL)) < 0)

{

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, 4);

exit (1);

}

while (!rx_done);

alt_dma_txchan_close(txchan);

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, 15);

delay();

// end of DMA stream translate

IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, 0);

startTimer();

while (1) {;}

if(uart)

{

fclose(uart);

}

return 0;

}