Creating Memory device for Nios II processor

If the data is already inside an onchip memory in the custom designed component it's a lot easier to access it directly through an Avalon MM slave interface than by using a DMA.

StMartin81, you don't need to edit the linker script. This would only be necessary if you wanted to place static variables in that area, which isn't what you want to do.

The address for your slave interface will be defined in system.h as a componentname_BASE constant, and you can use it either with a pointer or the IORD/IOWR macros, as explained by Cris72.

If you plan to use pointers, be careful with the data cache. Either invalidate the cache before reading the data, or change the pointer into a uncached pointer (by setting bit 32 as explained by Cris72 or by using the alt_remap_uncached() function). The IORD/IOWR automatically bypass the cache.