From: Tadas <tpt@pupa.da.ru>
To: u-boot@lists.denx.de
Subject: [U-Boot-Users] ppc405gp cpu problems
Date: Fri, 17 Sep 2004 00:13:49 +0300 [thread overview]
Message-ID: <004101c49c32$0f8a8290$030aa8c0@t> (raw)
In-Reply-To: 20040912164115.E8EC6C1430@atlas.denx.de
Second problem solved, seems cpu realy behave strangely,
I placed ram initialization at the very begining of bootloader and now it
works.
also there was some incorect timing but it is not likely to cause problem,
(becase fixing that did not helped)
ram just must be initialized before any other peripherials
(dont know why but now it works ok) at first the first thing initilalized
was UART.
>>>
>>> first problem with bootloader:
>>>...
>>> Seems everybody else is executing this code without problems
>Indeed. Are you sure your CPU can read the flash contents without
>problems?
The reson of this one is till unknown, but it does not matter, anyway.
I also found, that some time ago this instruction also was removed on
ppcboot so someone
had this problem too.
http://cvs.tuxbox.org/cgi-bin/viewcvs.cgi/tuxbox/boot/ppcboot/ppc4xx/Attic/start.S?rev=1.2&content-type=text/vnd.viewcvs-markup
#if 1 /* test-only */
addi r4,r0,0x1000 // set ME bit (Machine Exceptions)
oris r4,r4,0x0002 // set CE bit (Critical Exceptions)
mtmsr r4 // change MSR
#else /* problems in rom2ram (see test-only in rom2ram!!!) */
addi r4,r0,0x0000 // dont set (!!!) ME bit (Machine
Exceptions)
oris r4,r4,0x0002 // set CE bit (Critical Exceptions)
mtmsr r4 // change MSR
#endif
as you see it is same instruction.
It would be interesting to know why this happens.
prev parent reply other threads:[~2004-09-16 21:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-09 15:06 [U-Boot-Users] MPC8540 FEC/TSEC -Issues while enabling both controllers Sudhakar
2004-09-10 1:30 ` [U-Boot-Users] What is the most simple ppc405gp board Tadas
2004-09-10 7:10 ` Wolfgang Denk
2004-09-10 7:41 ` Stefan Roese
2004-09-10 12:36 ` Tadas
2004-09-10 15:34 ` Stefan Roese
2004-09-12 2:09 ` [U-Boot-Users] ppc405gp cpu problems Tadas
2004-09-12 16:41 ` Wolfgang Denk
2004-09-16 21:13 ` Tadas [this message]
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