direct memory access possible?

[Gravis]

is it possible (with it's current configuration) to directly access the RAM on the Parallella from the Epiphany? I'm interested in bypassing the ARM for increased I/O speed.

[ysapir]

The Epiphany works in the physical memory space. You can address (almost) any memory location on the board directly. Doing so outside of the EMEM range may crash your Linux system.

[Gravis]

[ysapir]

[Gravis]

[ysapir]

As stated above, the Epiphnay works in the physical address space. Out of the 32-bit (4GB) space, there are a few 1MB slices assigned to physical eCores. The system's DRAM consumes so-and-so memory as well, out of the same 4GB pool. In the Parallella, the first 1GB of memory space is occupied by the physical DRAM. The space starting at 0x80800000 is occupied by the Epiphany.

[Gravis]

[ysapir]

The entire space is not "taken". Part of it is allocated for the Epiphany chip. Both ARM and Epiphany "see" the same 4GB space. However, in your ARM Linux program, you don't "see" this space directly. You "see" the virtual address space, and you need mappings to "get out" to physical space.

[Gravis]

[Gravis]

umm... hello?