About IDE_DIRECT on PCMCIA port in ppcboot and linux

About IDE_DIRECT on PCMCIA port in ppcboot and linux

[Dross Zhou]

Hello all:
	We have get the schematic from Steven.
I have some question about the driver in ppcboot and
linux.

1.Why in ppcboot/include/pcmcia.h , all memory windows
have defined same in all boards.These values can be
changed ( if fit with address encode)?
If we just use PCMCIA as IDE , pcmcia_init() will not
been called()?

2.IDE just need a hw_regs_t(via PCMCIA's port) to
access IDE's register and a IRQ , these are enough?

3.If we use normal harddisk(as same in PC), Can this
driver do them?


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

mem= flag behaviour

[David Updegraff]

Hi.

I'm trying to keep a small trace buffer over re-boots
of linux from ppcboot, so give a mem=31M flag to linux
kernel.  Yet by the time linux is up, it has overwritten
that memory anyway..   PPCBOOT is properly leaving it
be (with PRAM feature) and correct arg. goes to kernel..

After 'reboot' from linux, the memory contents of
the last meg are still valid (in ppcboot) but by the time linux
is back up, the region has been trashed.  Why?

Help, please.  How to prevent linux from talking to
that memory region during bootup?

--
David Updegraff / dave@cray.com


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

Re: mem= flag behaviour

[Wolfgang Denk]

Dear David,

in message <3D062232.3010003@cray.com> you wrote:
>
> I'm trying to keep a small trace buffer over re-boots
> of linux from ppcboot, so give a mem=31M flag to linux
> kernel.  Yet by the time linux is up, it has overwritten
> that memory anyway..   PPCBOOT is properly leaving it
> be (with PRAM feature) and correct arg. goes to kernel..

Let me guess... you boot with a ramdisk image?

> After 'reboot' from linux, the memory contents of
> the last meg are still valid (in ppcboot) but by the time linux
> is back up, the region has been trashed.  Why?

If you use a ramdisk image, you should read the documentation for the
"initrd_high" environment variable in
http://www.denx.de/doc/TQM8xxL/ppcboot.html#PPCBOOT-VARIABLES
(or in the PPCBoot README).

> Help, please.  How to prevent linux from talking to
> that memory region during bootup?

Linux does not use the memory beyond what you tell it with "mem=".

Hope this helps...

[BTW: your CD is in the mail.]

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Machines take me by surprise with great frequency.      - Alan Turing

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