Great, I will do so.

As far as trying to trigger the read() function for the device goes, I have
been trying to use an inb() command from the kernel.  However, I am not sure
I have the address mapping right.

I see in /m5/srv/dev/alpha/Tsunami.py:87 that there is already an instance
of a BadDevice as the frame buffer pointer in the Tsunami platform.

...

fb = BadDevice(pio_addr=0x801fc0003d0, devicename='FrameBuffer')

...

Is there a simple way to trigger the read() function of this frame buffer
BadDevice device?  I am trying a simple inb(0x801fc0003d0) from the kernel,
but it seems to cause the OS to hang.

Thanks again,
Alex Edwards



On Mon, Jun 27, 2011 at 7:20 PM, Ali Saidi <[email protected]> wrote:

> You can take a look at the DEC Tsunami documentation and find an address
> that is unassigned.
>
> Ali
>
> On Jun 27, 2011, at 5:00 PM, Alex Edwards wrote:
>
> > Hi All,
> >
> > I am trying to add a simple simple BadDevice device to the ALPHA_FS
> system, but I am not sure what pio_addr to specify in FSConfig.py.
> >
> > I am going to use BadDevice as a model for a really really simple "read
> from a register"/"write to a register" device, so it seemed like starting
> with the basic BadDevice model that simply panics upon attempting read/write
> was a good start.
> >
> > Is there a given address range that is unused in the ALPHA_FS system in
> gem5?  How should I choose this pio_addr value?  I will only need to be
> accessing this "device" from kernel space, so I was hoping to simply
> inb(pio_addr) and that this would cause a panic?
> >
> > Further, when specifying pio_addr, it must be a physical address, right?
>  Thus, I'll need to know its corresponding virtual address when trying to
> read from the "device" in the linux kernel?  Or is there some section of
> memory in ALPHA_FS that is an identity mapping when doing address
> translation?  Anyone know?
> >
> >
> > Thanks much,
> >
> > Alex
> > _______________________________________________
> > gem5-users mailing list
> > [email protected]
> > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
>
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