Re: need advice on howto access memory from fpga and cpu

[srinivas bakki <srinivas.bakki@xxxxxxxxx>]

If you don't want dynamic memory allocation for framebuffer and neither do you want it in the user space, All you need is to pass

memmap = <size>$<start address> to the kernel and then write  a kernel module module where you ioremap that physical address space.

This is just like any other device driver where device registers are mapped.

On Wed, Oct 30, 2013 at 7:56 PM, Kai <kai@xxxxxxxxxx> wrote:

On Wed, Oct 30, 2013 at 04:20:30PM +0530, srinivas bakki wrote:
> But otherwise am wondering why would you need to tell the FPGA these
> kernel mapped addresses ? How is it connected to the memory module ?

The FPGA seems to have direct access to the memory. If I would allocate
memory for the framebuffer dynamically, I would first have to find out
the physical adress of this area, and then tell it to the FPGA, so it
can read the frames from there. We are implementing a "GPU" on the FPGA
here, or at least something that's reading frames from the RAM, to send
it to the VGA port.

--
Grüße, Kai

"In a world without walls and fences, who needs Windows and Gates?"

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