public inbox for u-boot@lists.denx.de
 help / color / mirror / Atom feed
From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] How to debug uboot code on Samsung S5pv210 chip by eclipse and JTAG?
Date: Wed, 30 May 2012 13:09:22 +0200	[thread overview]
Message-ID: <201205301309.23163.marex@denx.de> (raw)
In-Reply-To: <20120530104426.825F22064A6@gemini.denx.de>

Dear Wolfgang Denk,

> Dear =?GB2312?B?vOHKrw==?=,
> 
> In message <CAKM5mEg9rbi8yLsQfjawE74gh-
eu9p7prSgP=TSX7P9RJiMQAw@mail.gmail.com> you wrote:
> >     I have found some tutorials to debug uboot an samsung 2440 and
> > 6410 chip by JTAG .I also known I must write a init program or script
> > first .But I don't known to debug uboot on S5pv210 and write the init
> > DDR script.Anyone gives me a guide to establish the process.
> 
> Why would you need to initialize DDR though the JTAG debugger?

The system has some BootROM, which does the DDR init. But without special header 
in the NAND, the DDR won't be inited ... that was my point about initing it via 
the debugger.

> The common use of a JTAG debugger to debug U-Boot is _not_ to
> initialize the system at all though JTAG, as this will be done by
> U-Boot.  Just start the CPU out of reset.
> 
> Actually on quite a number of architectures U-Boot expects to find a
> virgin CPU right out of reset, and any previous meddling with the
> configuration may have unexpected (and usually adverse) effects.
> Better don't do it.
> 
> Best regards,
> 
> Wolfgang Denk

Best regards,
Marek Vasut

  reply	other threads:[~2012-05-30 11:09 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-29  5:53 [U-Boot] How to debug uboot code on Samsung S5pv210 chip by eclipse and JTAG? 坚石
2012-05-29 14:44 ` Marek Vasut
     [not found]   ` <CAKM5mEhnUc0P1811GM9cXE+_etO9=k_KsswbOfWRjPBFdfu-NA@mail.gmail.com>
2012-05-30 10:27     ` Marek Vasut
2012-05-30 10:44 ` Wolfgang Denk
2012-05-30 11:09   ` Marek Vasut [this message]
2012-05-30 14:02     ` Wolfgang Denk

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=201205301309.23163.marex@denx.de \
    --to=marex@denx.de \
    --cc=u-boot@lists.denx.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox