regarding DMA memory to memory copy in NIOS II

here is my codes. I want to verify the result and display at the end,
however I got like "cdcd", what's wrong? thanks


/*
 * "Hello World" example.
 *
 * This example prints 'Hello from Nios II' to the STDOUT stream. It
runs on
 * the Nios II 'standard', 'full_featured', 'fast', and 'low_cost'
example
 * designs. It runs with or without the MicroC/OS-II RTOS and requires
a STDOUT
 * device in your system's hardware.
 * The memory footprint of this hosted application is ~69 kbytes by
default
 * using the standard reference design.
 *
 * For a reduced footprint version of this template, and an
explanation of how
 * to reduce the memory footprint for a given application, see the
 * "small_hello_world" template.
 *
 */

#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 has
*   been received.
*/
static void done (void* handle, void* data)
{
  rx_done++;
}

int main(int argc, char* argv[], char* envp[])
{
  int rc;
  static char buff[256]="abcdefghijklmn\0";
  alt_dma_txchan txchan;
  alt_dma_rxchan rxchan;

  void* tx_data = (void*) buff;                 /* pointer to data to
send */
  void* rx_buffer = (void*) 0x01000000; /* on_chip_memory addr*/


  /* 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);
  }

   /* wait for transfer to complete */
    while (!rx_done);
        printf ("Transfer successful!\n");
        printf ("%s",(ONCHIP_MEMORY_0_BASE));
    return 0;
}

BigJamesLau@gmail.com pisze:
> here is my codes. I want to verify the result and display at the end,
> however I got like "cdcd", what's wrong? thanks
> 
> 
> /*
>  * "Hello World" example.
>  *
>  * This example prints 'Hello from Nios II' to the STDOUT stream. It
> runs on
>  * the Nios II 'standard', 'full_featured', 'fast', and 'low_cost'
> example
>  * designs. It runs with or without the MicroC/OS-II RTOS and requires
> a STDOUT
>  * device in your system's hardware.
>  * The memory footprint of this hosted application is ~69 kbytes by
> default
>  * using the standard reference design.
>  *
>  * For a reduced footprint version of this template, and an
> explanation of how
>  * to reduce the memory footprint for a given application, see the
>  * "small_hello_world" template.
>  *
>  */
> 
> #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 has
> *   been received.
> */
> static void done (void* handle, void* data)
> {
>   rx_done++;
> }
> 
> int main(int argc, char* argv[], char* envp[])
> {
>   int rc;
>   static char buff[256]="abcdefghijklmn\0";
>   alt_dma_txchan txchan;
>   alt_dma_rxchan rxchan;
> 
>   void* tx_data = (void*) buff;                 /* pointer to data to
> send */
>   void* rx_buffer = (void*) 0x01000000; /* on_chip_memory addr*/
> 
> 
>   /* 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);
>   }
> 
>    /* wait for transfer to complete */
>     while (!rx_done);
>         printf ("Transfer successful!\n");
>         printf ("%s",(ONCHIP_MEMORY_0_BASE));
>     return 0;
> }
What is set in system configuration ?

Adam

BigJamesLau@gmail.com wrote:

> here is my codes. I want to verify the result and display at the end,
> however I got like "cdcd", what's wrong? thanks

You need to ensure that the memory involved in the transfer is not cached
- you can simply set bit 31 of the address to bypass the NIOS cache. I use
a macro thusly:
#define UNCACHED(addr)              ((1<<31)|(addr))

What's the width on your DMA register? Not 7 bits I hope! :O

You also use 0x01000000 for the rx_buffer yet you're printing the contents
of INCHIP_MEMORY_0_BASE, which IMHO is bad practise.

Otherwise it looks OK to me...

Regards,

-- 
Mark McDougall, Engineer
Virtual Logic Pty Ltd, <http://www.vl.com.au>
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266

quartus II sopc builder, jtag debugging mode, tri-state avalon bridge,
sdram, on-chip ram, etc



On Jan 29, 5:04 am, G=F3rski Adam
<gorskia@.................wp....................pl..................>
wrote:
> BigJames...@gmail.com pisze:
>
> > here is my codes. I want to verify the result and display at the end,
> > however I got like "cdcd", what's wrong? thanks
>
> > /*
> >  * "Hello World" example.
> >  *
> >  * This example prints 'Hello from Nios II' to the STDOUT stream. It
> > runs on
> >  * the Nios II 'standard', 'full_featured', 'fast', and 'low_cost'
> > example
> >  * designs. It runs with or without the MicroC/OS-II RTOS and requires
> > a STDOUT
> >  * device in your system's hardware.
> >  * The memory footprint of this hosted application is ~69 kbytes by
> > default
> >  * using the standard reference design.
> >  *
> >  * For a reduced footprint version of this template, and an
> > explanation of how
> >  * to reduce the memory footprint for a given application, see the
> >  * "small_hello_world" template.
> >  *
> >  */
>
> > #include <stdio.h>
> > #include <stdlib.h>
> > #include <sys/alt_dma.h>
> > #include "system.h"
>
> > static volatile int rx_done =3D 0;
>
> > /*
> > *   Callback function that obtains notification that the data has
> > *   been received.
> > */
> > static void done (void* handle, void* data)
> > {
> >   rx_done++;
> > }
>
> > int main(int argc, char* argv[], char* envp[])
> > {
> >   int rc;
> >   static char buff[256]=3D"abcdefghijklmn\0";
> >   alt_dma_txchan txchan;
> >   alt_dma_rxchan rxchan;
>
> >   void* tx_data =3D (void*) buff;                 /* pointer to data to
> > send */
> >   void* rx_buffer =3D (void*) 0x01000000; /* on_chip_memory addr*/
>
> >   /* Create the transmit channel */
> >   if ((txchan =3D alt_dma_txchan_open("/dev/dma_0")) =3D=3D NULL)
> >   {
> >     printf ("Failed to open transmit channel\n");
> >     exit (1);
> >   }
>
> >   /* Create the receive channel */
> >   if ((rxchan =3Dalt_dma_rxchan_open("/dev/dma_0")) =3D=3D NULL)
> >   {
> >     printf ("Failed to open receive channel\n");
> >     exit (1);
> >   }
>
> >   /* Post the transmit request */
> >   if ((rc =3D alt_dma_txchan_send (txchan,tx_data,128,NULL,NULL)) < 0)
> >   {
> >     printf ("Failed to post transmit request, reason =3D %i\n", rc);
> >     exit (1);
> >   }
>
> >   /* Post the receive request */
> >   if ((rc =3D alt_dma_rxchan_prepare (rxchan,rx_buffer,128,done,NULL)) <=

> > 0)
> >   {
> >     printf ("Failed to post read request, reason =3D %i\n", rc);
> >     exit (1);
> >   }
>
> >    /* wait for transfer to complete */
> >     while (!rx_done);
> >         printf ("Transfer successful!\n");
> >         printf ("%s",(ONCHIP_MEMORY_0_BASE));
> >     return 0;
> > }
>
> What is set in system configuration ?
>
> Adam

BigJamesLau@gmail.com pisze:
> quartus II sopc builder, jtag debugging mode, tri-state avalon bridge,
> sdram, on-chip ram, etc
> 
Not in quartus.
NIOS IDE -> Project -> System lib config

Adam