MPC8xx DPRAM : m8xx_cpm_hostalloc

[Tobias Otto-Adamczak]

I assume the subject is m8xx_cpm_dpalloc, not m8xx_cpm_hostalloc.

> I am currently working with a MPC860 (Linux kernel 2.2.13)
> and I need more DPRAM space for my BD/buffers, than the
> space between IMMR+0x2800 - IMMR+0x2F00 (1792 bytes).

You can place your buffers outside the DPRAM (you can use
m8xx_cpm_hostalloc for that).

> I know the 860 has 5K of DPRAM : 4K + 1K of parameter RAM.
>
> So, I have tried to modify the value of
>     CPM_DATAONLY_BASE   from 0x0800 to 0x0000
>     CPM_DATAONLY_SIZE     from 0x0700 to 0x1000

These values were chosen in regard to possibly active microcode relocation
patches that could reside in the DPRAM. Does your boot code / monitor
program / linux kernel load and use microcode relocation patches ? If so,
you should determine the area where they reside so that you know which
space is left for you in DPRAM.

> but my kernel (compiled with those values) stucks early at boot time :
>
> ...
> Uncompressing Linux... done.
> Now booting the kernel
>     -(and no more)-

Looks like your linux console doesn't work. Which SCC/SMC are you using
as console ?

Ciao - Tobias


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/