Subject: Re: Jornada 820
To: Francois-Rene Rideau <>
From: Francois-Rene Rideau <>
List: port-hpcarm
Date: 06/20/2002 05:13:55
Dear hpcarm hackers,

someone told me where to download the ARM ARM, so now I'm less clueless.
The CPSR achieved by hpcboot is 600000df -- that's *CORRECT*:
System mode (privileged, but normal registers), IRQ&FIQ disabled.

The actual issue I stumbled into is that some device on the jornada 820
is constantly writing at 0xc005c080: a 16-bit counter incremented every 1ms.
Since I was trying to load the kernel at its usual 0xc0008000 address,
I was running into big problems! The relative impredictability of bugs,
and the fact that they were related to memory location made me suspect
some DMA device to be mapped there; but although the DMA devices were
also mapped not far away, the only writing one had a 0 length buffer
at a different place (but I disabled all channels anyway).

All in all, I don't know how to disable that real-time clock device.
Do you have an idea?
Workaround: move the kernel higher in memory, using the 400kb of memory
as static buffers for the video and more.

Hum. How far did you netbsd hackers go into porting your system?
How easy would it be for me to cross-compile netbsd from Linux?

PS: sorry about the doubts I cluelessly emitted about hpcboot.
Being ignorant, I was emitting wild hypotheses. Well, apparently,
one of the wild hypotheses ("some device is modifying memory under my feet")
happened to be sadly true!

Yours freely,

[ François-René ÐVB Rideau | Reflection&Cybernethics | ]
[  TUNES project for a Free Reflective Computing System  |  ]
Maybe Jesus was right when he said that the meek shall inherit the earth
-- but they inherit very small plots, about six feet by three.
		-- Lazarus Long