Why AXI DMAreads only 16 bit from DDR3 instead of 32 bits in my design?

[daryon]

Dear all,

 

I am working with Vivado 2017.3 targeting a KC705 evaluation board (with Kintex-7 xc7k325ffg900 FPGA).

 

I have block design omprised of a DDR3, an AXI DMA and a BRAM connected through AXI Interconnect all of them controlled by a Microblaze.

 

My Objectives :

a) I want to write some data to the DDR3 with Microblaze through a C code writtenin SDK ---> This part was successfull.

 

b) Then, I want to read back those data from DDR3 and write them to the BRAM through an AXI DMA connected to a AXIStream FIFO.  ----> The connections are as shown in the attached photo of my design and the bitstream was generated successfully.

 

c) I wrote a code in SDK in C to write some data to first 16 addresses of DDR3 which was successfullbecause when I verify the content of DDR3 via Microblaze, my written data are there.

 

d) finnally, in my C code I have defined a function to read data fom DDR3 into the AXI DMA ----> My problem is hear when I read the content of the first address in AXI DMA, it contains ONLY 16 bits of my data instead of 32-bit written data in it. As you see in the XSDB result and also UART result, instead of the value 0xBABABEE0 writtnenin the first AXI DMA address (0x41E00000), I receive 0xBABA3002 !!!!

 

For more clarification, I put the schematic of my design, my C code in SDK and the results shown on UART and XSDB.

 

Can anyone help me to resolve this problem? I am really confused! Thank in advance for your kind replies and helps.

 

Bests,

Daryon

 

 

 

My design schematic : Attachedsystem.pdf file

 

 

My C code written in SDK :

 

/***************************** Include Files *********************************/

#include "xparameters.h"
#include <xil_printf.h>
#include <stdio.h>
#include "xil_exception.h"
#include "xuartlite.h"
#include "xbram.h"




int DDR3datawriting( int *ddr3_addr1,  int *ddr3_addr2,  int *ddr3_addr3,  int *ddr3_addr4,  int *ddr3_addr5,  int *ddr3_addr6,  int *ddr3_addr7,  int *ddr3_addr8,  int *ddr3_addr9,  int *ddr3_addr10,  int *ddr3_addr11,  int *ddr3_addr12,  int *ddr3_addr13,  int *ddr3_addr14,  int *ddr3_addr15,  int *ddr3_addr16);
int DDR3datareading( int *dma_addr1,  int *ddr3_addr1);


/************************** Variable Definitions *****************************/


//Global variables
//unsigned int *ddr3_addr1, *ddr3_addr2, *ddr3_addr3, *ddr3_addr4, *ddr3_addr5, *ddr3_addr6, *ddr3_addr7, *ddr3_addr8, *ddr3_addr9, *ddr3_addr10, *ddr3_addr11, *ddr3_addr12, *ddr3_addr13, *ddr3_addr14, *ddr3_addr15, *ddr3_addr16;

//



int main()
{

	//Local variable
	int Status;
	 int ddr3_addr1, ddr3_addr2, ddr3_addr3, ddr3_addr4, ddr3_addr5, ddr3_addr6, ddr3_addr7, ddr3_addr8, ddr3_addr9, ddr3_addr10, ddr3_addr11, ddr3_addr12, ddr3_addr13, ddr3_addr14, ddr3_addr15, ddr3_addr16;
	 int dma_addr1;

	
	// Writing data into DDR3 memory
	Status = DDR3datawriting(&ddr3_addr1, &ddr3_addr2, &ddr3_addr3, &ddr3_addr4, &ddr3_addr5, &ddr3_addr6, &ddr3_addr7, &ddr3_addr8, &ddr3_addr9, &ddr3_addr10, &ddr3_addr11, &ddr3_addr12, &ddr3_addr13, &ddr3_addr14, &ddr3_addr15, &ddr3_addr16);

	//Checking the validity of returned variables value to the main function
	xil_printf("\n\r****** Returned valued of ddr3_addr1 to the main() function = %x\n\r",ddr3_addr1);
	xil_printf("\n\r The address of ddr3_addr1 = %x\n\r", &ddr3_addr1);

	// Reading data from DDR3 into the AXI DMA (axi_dma_0)
	Status = DDR3datareading(&dma_addr1,&ddr3_addr1);

    //End of program
	return Status;
}

/****************************************************************************/

int DDR3datawriting( int *ddr3_addr1, int *ddr3_addr2, int *ddr3_addr3, int *ddr3_addr4, int *ddr3_addr5, int *ddr3_addr6, int *ddr3_addr7, int *ddr3_addr8, int *ddr3_addr9, int *ddr3_addr10, int *ddr3_addr11, int *ddr3_addr12, int *ddr3_addr13, int *ddr3_addr14, int *ddr3_addr15, int *ddr3_addr16)
{

	//unsigned int ddr3_addr1, ddr3_addr2, ddr3_addr3, ddr3_addr4, ddr3_addr5, ddr3_addr6, ddr3_addr7, ddr3_addr8, ddr3_addr9,ddr3_addr10,ddr3_addr11,ddr3_addr12,ddr3_addr13,ddr3_addr14,ddr3_addr15,ddr3_addr16;

	xil_printf("\n\rStarting to write some data into DDR3 memory...\n\r");
	xil_printf("The BaseAddress for DDR3 Memory is 0x8000_0000\n\r");

	//ddr3_addr1  = *(int*)0x80000000;
	//ddr3_addr1  = 0xDEADBEE0;
	*ddr3_addr1  = *(int*)0x80000000 = 0xBABABEE0;
	*ddr3_addr2  = *(int*)0x80000004 = 0xDEADBEE1;
	*ddr3_addr3  = *(int*)0x80000008 = 0xDEADBEE2;
	*ddr3_addr4  = *(int*)0x8000000C = 0xDEADBEE3;
	*ddr3_addr5  = *(int*)0x80000010 = 0xDEADBEE4;
	*ddr3_addr6  = *(int*)0x80000014 = 0xDEADBEE5;
	*ddr3_addr7  = *(int*)0x80000018 = 0xDEADBEE6;
	*ddr3_addr8  = *(int*)0x8000001C = 0xDEADBEE7;
	*ddr3_addr9  = *(int*)0x80000020 = 0xDEADBEE8;
	*ddr3_addr10 = *(int*)0x80000024 = 0xDEADBEE9;
	*ddr3_addr11 = *(int*)0x80000028 = 0xDEADBEEA;
	*ddr3_addr12 = *(int*)0x8000002C = 0xDEADBEEB;
	*ddr3_addr13 = *(int*)0x80000030 = 0xDEADBEEC;
	*ddr3_addr14 = *(int*)0x80000034 = 0xDEADBEED;
	*ddr3_addr15 = *(int*)0x80000038 = 0xDEADBEEE;
	*ddr3_addr16 = *(int*)0x8000003C = 0xDEADBEEF;

	xil_printf("\n\r Data written at 0x80000000 is %6x\n\r",*ddr3_addr1);
	xil_printf("\n\r Data written at 0x80000004 is %6x\n\r",*ddr3_addr2);
	xil_printf("\n\r Data written at 0x80000008 is %6x\n\r",*ddr3_addr3);
	xil_printf("\n\r Data written at 0x8000000C is %6x\n\r",*ddr3_addr4);
	xil_printf("\n\r Data written at 0x80000010 is %6x\n\r",*ddr3_addr5);
	xil_printf("\n\r Data written at 0x80000014 is %6x\n\r",*ddr3_addr6);
	xil_printf("\n\r Data written at 0x80000018 is %6x\n\r",*ddr3_addr7);
	xil_printf("\n\r Data written at 0x8000001C is %6x\n\r",*ddr3_addr8);
	xil_printf("\n\r Data written at 0x80000020 is %6x\n\r",*ddr3_addr9);
	xil_printf("\n\r Data written at 0x80000024 is %6x\n\r",*ddr3_addr10);
	xil_printf("\n\r Data written at 0x80000028 is %6x\n\r",*ddr3_addr11);
	xil_printf("\n\r Data written at 0x8000002C is %6x\n\r",*ddr3_addr12);
	xil_printf("\n\r Data written at 0x80000030 is %6x\n\r",*ddr3_addr13);
	xil_printf("\n\r Data written at 0x80000034 is %6x\n\r",*ddr3_addr14);
	xil_printf("\n\r Data written at 0x80000038 is %6x\n\r",*ddr3_addr15);
	xil_printf("\n\r Data written at 0x8000003C is %6x\n\r",*ddr3_addr16);
	xil_printf("\n\r-----------------------------------------------------------------------\n\r");

	return *ddr3_addr1;

}
/*****************************************************************************/
int DDR3datareading(int *dma_addr1, int *ddr3_addr1)
{
	//dma_addr2,dma_addr3,dma_addr4,dma_addr5,dma_addr6,dma_addr7,dma_addr8,dma_addr9,dma_addr10,dma_addr11,dma_addr12,dma_addr13,dma_addr14,dma_addr15,dma_addr16;

	xil_printf("\n\rStarting to read some data from DDR3 memory into the AXI DMA...\n\r");
	xil_printf("The BaseAddress for AXI DMA is 0x41E0_0000\n\r");


	//*dma_addr1  = *(int*)ddr3_addr1;
	//*(int*)0x41e00000 = *(int*)ddr3_addr1;
	*dma_addr1 = *(unsigned int*)0x41e00000 = *ddr3_addr1;

	xil_printf("\n\r Data read from 0x41E00000 is %6x\n\r",*dma_addr1);
	xil_printf("\n\r-----------------------------------------------------------------------\n\r");
	xil_printf("\n\r new value of 0x41E00000 is %6x\n\r",*(int*)0x41e00000);
	return *dma_addr1;
}

 

The result shown on UART Interface : (attached uart1.png file)

The result shown on UART Interface : (attached xsdb1.png file)

system.pdf

[jpeyron]

Hi @daryon,

Can you attach a screen scot of your DMA setting? Here is a thread that discusses the DMA settings.

thank you,

Jon

[xc6lx45]

Hi,

I think your C code does not do what it suggests it does.

Here...

int ddr3_addr1, ddr3_addr2, ddr3_addr3, ddr3_addr4, ddr3_addr5, ddr3_addr6, ddr3_addr7, ddr3_addr8, ddr3_addr9, ddr3_addr10, ddr3_addr11, ddr3_addr12, ddr3_addr13, ddr3_addr14, ddr3_addr15, ddr3_addr16;

... you create variables ddr3_addr on the stack.

Here ...

Status = DDR3datawriting(&ddr3_addr1, &ddr3_addr2, &ddr3_addr3, &ddr3_addr4, &ddr3_addr5, &ddr3_addr6, &ddr3_addr7, &ddr3_addr8, &ddr3_addr9, &ddr3_addr10, &ddr3_addr11, &ddr3_addr12, &ddr3_addr13, &ddr3_addr14, &ddr3_addr15, &ddr3_addr16);

...

you give the address of the variables (still on the stack!) to the function and here ...

*ddr3_addr1 = *(int*)0x80000000 = 0xBABABEE0;

you write the value 0xBABABEE0 into abovementioned stack variable ddr3_addr1 in main(). This is not what you want, probably.

Further, the same value goes into memory address 0x80000000 (this looks meaningful - base address of your DRAM).

Here...

xil_printf("\n\r Data written at 0x80000000 is %6x\n\r",*ddr3_addr1);

you read it from the stack variable.

My suggestion: Clean up the code to the essentials, five lines plus headers. And use volatile  for pointers to force hardware IO (otherwise the processor cache may delay the write and / or intercept the read).

Link: Discussion on chained assignments in C. In a nutshell: Do not use unless you feel you are entitled to a different opinion ?

[daryon]

Dear @jpeyron

Attached, is a snapshot of axi_amd_0 and also the axi stream FIFO modules settings in my design:

 

 

[xc6lx45]

>> Can you please do the modifications that you mean on my initial C code posted here and reply to me that might help to overcome this problem??

I'm sure I could but it might be disrespectful to lots of other folks on this forum eager to do your work for you. I suggest let's wait and give them a chance

 

 

[xc6lx45]

That's the spirit

And I'm sure people will be willing to help when you're stuck.

Just as a reality check: writing that above mail took me about 30 min (for whatever reasons, maybe it just beats crossword puzzles). How long did you spend to read it?