public inbox for linuxppc-dev@ozlabs.org 
 help / color / mirror / Atom feed
From: Andrei Konovalov <akonovalov@ru•mvista.com>
To: jonathan@jonmasters•org
Cc: akpm@osdl•org, linuxppc-embedded@ozlabs•org
Subject: Re: [PATCH][PPC32] Xilinx ML300 board support (very basic)
Date: Mon, 11 Oct 2004 15:53:23 +0400	[thread overview]
Message-ID: <416A7433.4080605@ru.mvista.com> (raw)
In-Reply-To: <35fb2e5904100912409628a94@mail.gmail.com>

Jon Masters wrote:
> On Fri, 08 Oct 2004 21:23:01 +0400, Andrei Konovalov
> <akonovalov@ru•mvista.com> wrote:
> 
> 
>>Adds minimal Xilinx ML300 board support (enough to boot with ramdisk).
>>The only peripheral devices supported are 16x50 compatible UARTs.
>>
>>Signed-off-by: Andrei Konovalov <akonovalov@ru•mvista.com>
> 
> 
> I'll test this if I get chance soon.
> 

Great!

> 
>>        /*
>>-        * At one point, we were getting machine checks.  Linux was not
>>-        * invalidating the data cache before it was enabled.  The
>>-        * following code was added to do that.  Soon after we had done
>>-        * that, we found the real reasons for the machine checks.  I've
>>-        * run the kernel a few times with the following code
>>-        * temporarily removed without any apparent problems.  However,
>>-        * I objdump'ed the kernel and boot code and found out that
>>-        * there were no other dccci's anywhere, so I put the code back
>>-        * in and have been reluctant to remove it.  It seems safer to
>>-        * just leave it here.
>>+        * Invalidate the data cache if the data cache is turned off.
>>+        * - The 405 core does not invalidate the data cache on power-up
>>+        *   or reset but does turn off the data cache. We cannot assume
>>+        *   that the cache contents are valid.
>>+        * - If the data cache is turned on this must have been done by
>>+        *   a bootloader and we assume that the cache contents are
>>+        *   valid.
>>         */
> 
> 
> Er...the caveat about the MSR is still worth noting - I had this
> problem and for a while couldn't figure out why the fsck the board
> wouldn't come up with cacheing enabled (I've written patches for
> debugging that turn off various cacheing by modifying the pte macros,
> etc.) and *still* believe we're not clean from unwanted machine checks
> here. Just FYI.
> 

The code which follows the comment above works for me with both ML300
and the Memec 2VP7 boards I have.
Do you mean that some boards (or FPGA designs) need cacheing to be
disabled completely?

If this is the case, and you have the patch that handles this, I would
welcome that patch to follow mine.

Is there any chance for me to reproduce that problem on my site with
the hardware I have (1. ML300; 2. Memec 2VP7 board plus the COMM and the
System ACE modules)?

> 
...
> 
>>+*     This program is free software; you can redistribute it and/or modify it
>>+*     under the terms of the GNU General Public License as published by the
>>+*     Free Software Foundation; either version 2 of the License, or (at your
>>+*     option) any later version.
> 
> 
> ...and then:
> 
> 
>>+*     Xilinx hardware products are not intended for use in life support
>>+*     appliances, devices, or systems. Use in such applications is
>>+*     expressly prohibited.
> 
> 
> I've always loved it how Xilinx GPL disclaimers cunningly aren't. They
> might want to wake up and smell the coffee at some point.

I know this doesn't look good.
If it *does* prevent this code from getting into the kernel tree I could
try contacting Xilinx (doubt it will help though - they have already
changed the copyrights once to be more community friendly).

> 
> Andrei, you'll want to modify the ML300 xparameters stuff to allow
> it's location to be specified by a parameter. People who want to use
> (ewww, spit) autogenerated Xilinx xparameters.h from their EDK will
> probably also want to choose where it lives.
> 

Why renaming someone's autogenerated xparameters.h into xparameters_my_ml300.h
and placing it into arch/ppc/platforms/4xx/xparameters/,
defining CONFIG_XILINX_MY_ML300, and adding
few lines to include/asm-ppc/xparameters.h like:

#if defined(CONFIG_XILINX_ML300)
#include <platforms/4xx/xparameters/xparameters_ml300.h>
#endif

+#if defined(CONFIG_XILINX_MY_ML300)
+#include <platforms/4xx/xparameters/xparameters_my_ml300.h>
+#endif

doesn't work in your oppinion?

> 
...
> 
> Jon.
> 
> 

Thanks,
Andrei

  reply	other threads:[~2004-10-11 11:43 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-10-08 17:23 [PATCH][PPC32] Xilinx ML300 board support (very basic) Andrei Konovalov
2004-10-09 19:40 ` Jon Masters
2004-10-11 11:53   ` Andrei Konovalov [this message]
2004-10-11 12:23     ` Jon Masters
2004-10-11 15:19   ` Tom Rini
2004-10-11 16:23     ` Jon Masters

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=416A7433.4080605@ru.mvista.com \
    --to=akonovalov@ru$(echo .)mvista.com \
    --cc=akpm@osdl$(echo .)org \
    --cc=jonathan@jonmasters$(echo .)org \
    --cc=linuxppc-embedded@ozlabs$(echo .)org \
    /path/to/YOUR_REPLY

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