This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Writing to External Memory Registers

Other Parts Discussed in Thread: AM1808

Curious if anybody can tell me how to access external memory from within a linux application?
I am using an AM1808 processor with DaVinci-PSP-SDK-03.21.00.04.  We have configured our FPGA at chip select 5.
In googling this, I see some posts asking if mmap() sys call should be used to access FPGA.  Originally I tried accessing the memory location as follows:
#define FIFO_BASE 0x66000000
#define FIFO_CHAN1 *(unsigned short*) (FIFO_BASE + 0x00)

void testFunc()
{
      FIFO_CHAN1 = 0x5555;
}

The problem....when I compile this application and download the uImage to my board...upon running my application, I receive the following error:
"Unable to handle kernel paging request at virtual address 66000000"  followed by a register dump.

Can someone suggest the appropriate way I should be accessing external memory in code? I know u-boot has the "mw" command to write directly to memory...but what can I use within my custom application?

Any help would be appreciated!