Re: How can I make flash writeable?

2 messages, 2 authors, 2008-10-18 · open the first message on its own page

Re: How can I make flash writeable?

From: Duy-Ky Nguyen <hidden>
Date: 2008-10-18 01:19:46

Hi Mark,

I guess you want to have RW filesystem for your Linux target.
If that's the case you need to have root filesystem as JFFS2.

There's a document MPC8313E-RDB BSP User's Guide comes with the MPC8313E-RDB 
package.
It has all info for several filesystems like NFS (network), Ramdisk 
(Read-Only), and JFFS2 (Read/Write)

Regards,

Duy-Ky

----- Original Message ----- 
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To: <redacted>
Sent: Friday, October 17, 2008 6:00 PM
Subject: Linuxppc-embedded Digest, Vol 50, Issue 30

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Today's Topics:

  1. Re: How can I make flash writeable? (Mark Bishop)
  2. Re: How can I make flash writeable? (Marco Stornelli)
  3. Re: Loadable module crashes at kernel stack overflow or
     machine check (Ben Gardiner)
  4. Re: Oops in during system run (Scott Wood)


----------------------------------------------------------------------

Message: 1
Date: Fri, 17 Oct 2008 08:33:52 -0400
From: Mark Bishop <redacted>
Subject: Re: How can I make flash writeable?
To: linuxppc-embedded@ozlabs.org
Message-ID: [off-list ref]
Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes";
format="flowed"



Ok, so bear with me.  I've read booting-without-of.txt in the
Documentation/powerpc directory and I modified a .dts file but now what?

I use ltib or u-boot to load that into the device or do I roll a
kernel with that file and flash the device with it?

Apologies for the less than technical questions.

Quoting Marco Stornelli [off-list ref]:
quoted
Hi Mark,
quoted
How can I tell which devices are mapped to /proc/mtd devices?
If I well understand the question, you'd like to change the partitions
layout (?), so you should check out the dts file to see the flash
layout, then you can specify there the partitions and change the
dimensions, if they are read-only...and so on.

Regards,

Mark Bishop ha scritto:
quoted
I am using the MPC8313E-RDB and I am having some problems using the
flash that comes on the board.  Let me preface this by saying that I
haven't worked in the embedded linux arena in about 10 years so I am
trying to catch up with all the new toys.

This board uses uBoot and it currently has 128M of DDR2, 8M flash and
32M NAND Flash.  I have a few questions:

How can I tell which memory device it uses to boot out of?
How can I tell which devices are mapped to /proc/mtd devices?


I want to create a writeable flash partition, is there a FAQ out there I
could look at.

All of this is after a few days of using Google to try and glean some
data from the internet.  And the books don't get here from Amazon until
Monday.

I would appreciate any help.  Even a RTFM - if you could point me to
TFM, it would greatly help.
_______________________________________________
Linuxppc-embedded mailing list
Linuxppc-embedded@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-embedded
--
Marco Stornelli
Embedded Software Engineer
CoRiTeL - Consorzio di Ricerca sulle Telecomunicazioni
http://www.coritel.it

marco.stornelli@coritel.it
+39 06 72582838


------------------------------

Message: 2
Date: Fri, 17 Oct 2008 15:13:58 +0200
From: Marco Stornelli <redacted>
Subject: Re: How can I make flash writeable?
To: Mark Bishop <redacted>
Cc: linuxppc-embedded@ozlabs.org
Message-ID: [off-list ref]
Content-Type: text/plain; charset=us-ascii

You have to compile it with the dtc compiler and load it with the uboot
bootm command, indeed, (at least with a recent uboot version) it has
three parameters: kernel, dtb (the name of dts compiled) and initrd. If
you want you can store the dtb in flash.

Regards,

Mark Bishop ha scritto:
quoted

Ok, so bear with me.  I've read booting-without-of.txt in the
Documentation/powerpc directory and I modified a .dts file but now what?

I use ltib or u-boot to load that into the device or do I roll a kernel
with that file and flash the device with it?

Apologies for the less than technical questions.

Quoting Marco Stornelli [off-list ref]:
quoted
Hi Mark,
quoted
How can I tell which devices are mapped to /proc/mtd devices?
If I well understand the question, you'd like to change the partitions
layout (?), so you should check out the dts file to see the flash
layout, then you can specify there the partitions and change the
dimensions, if they are read-only...and so on.

Regards,

Mark Bishop ha scritto:
quoted
I am using the MPC8313E-RDB and I am having some problems using the
flash that comes on the board.  Let me preface this by saying that I
haven't worked in the embedded linux arena in about 10 years so I am
trying to catch up with all the new toys.

This board uses uBoot and it currently has 128M of DDR2, 8M flash and
32M NAND Flash.  I have a few questions:

How can I tell which memory device it uses to boot out of?
How can I tell which devices are mapped to /proc/mtd devices?


I want to create a writeable flash partition, is there a FAQ out there 
I
could look at.

All of this is after a few days of using Google to try and glean some
data from the internet.  And the books don't get here from Amazon until
Monday.

I would appreciate any help.  Even a RTFM - if you could point me to
TFM, it would greatly help.
_______________________________________________
Linuxppc-embedded mailing list
Linuxppc-embedded@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-embedded
-- 
Marco Stornelli
Embedded Software Engineer
CoRiTeL - Consorzio di Ricerca sulle Telecomunicazioni
http://www.coritel.it

marco.stornelli@coritel.it
+39 06 72582838
_______________________________________________
Linuxppc-embedded mailing list
Linuxppc-embedded@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-embedded
-- 
Marco Stornelli
Embedded Software Engineer
CoRiTeL - Consorzio di Ricerca sulle Telecomunicazioni
http://www.coritel.it

marco.stornelli@coritel.it
+39 06 72582838


------------------------------

Message: 3
Date: Fri, 17 Oct 2008 09:12:07 -0400
From: Ben Gardiner <redacted>
Subject: Re: Loadable module crashes at kernel stack overflow or
machine check
To: Ganesh Kumar N M <redacted>
Cc: linuxppc-dev@ozlabs.org, linuxppc-embedded@ozlabs.org
Message-ID: [off-list ref]
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"

Ganesh Kumar N M wrote:
quoted
*Hi All,*
**
*    I'm working on MPC860 with Montavista linux 2.4.18*
*We have a Linux kernel loadable module which on loading*
*panicks after some random time say 8 hours, 4 hours or so*
*the oops outputs say either machine check exception or *
*kernel stack overflow (randomly both show up) a**re as below:*
I don't know for sure what could be causing your problem. I can only
suggest some patches that have helped us in the past.

I'm not familiar with Montavista's kernel versions; but I know our
2.4.24 kernel did not have the 'separate I-TLB error and miss handling'
patch (
http://ozlabs.org/pipermail/linuxppc-embedded/2005-January/016382.html )
which caused our applications to segfault for not apparent reason.

I also suggest applying the CPU15 fix (
http://git.denx.de/?p=linuxppc_2_4_devel.git;a=commit;h=baf9a6caca75b1f338ae370669e5882809000164
and
http://git.denx.de/?p=linuxppc_2_4_devel.git;a=commit;h=3ad403717f1d9c6a09ec41a5b016ac5245591122
) and enabling it temporarily to see if the problem could be the unlucky
placement of a branch instruction at the end of a page; but evaluate the
performance of your application carefully if you are considering running
production code with the patch enabled as it introduces significant
overhead.

Regards,

Ben Gardiner
Nanometrics Seismological Instruments
250 Herzberg Rd., Kanata, ON, CA, K2K 2A1
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------------------------------

Message: 4
Date: Fri, 17 Oct 2008 10:21:32 -0500
From: Scott Wood <redacted>
Subject: Re: Oops in during system run
To: Sreejith <redacted>
Cc: linuxppc-dev@ozlabs.org, linuxppc-embedded@ozlabs.org
Message-ID: [off-list ref]
Content-Type: text/plain; charset=us-ascii

On Fri, Oct 17, 2008 at 03:49:12PM +0530, Sreejith wrote:
quoted
This is a peculiar Oops we are encountering during the running of our 
board
(sh4) architecture
So why are you posting to powerpc lists?
quoted
PC  : 844240f8 SP  : 88d1ff44 SR  : 400080f0 TEA : c0169d64    Tainted: P
With proprietary modules, too.
quoted
Give you valuable suggestions!!
Debug the code?
Switch to powerpc? :-)

-Scott


------------------------------

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End of Linuxppc-embedded Digest, Vol 50, Issue 30
*************************************************

Re: How can I make flash writeable?

From: Wolfgang Denk <hidden>
Date: 2008-10-18 08:00:47

Dear "Duy-Ky Nguyen",

In message [off-list ref] you wrote:
I guess you want to have RW filesystem for your Linux target.
If that's the case you need to have root filesystem as JFFS2.
This is not correct. You can use a read-only root file system combined
with additionala ,writable file systems.
There's a document MPC8313E-RDB BSP User's Guide comes with the MPC8313E-RDB 
package.
It has all info for several filesystems like NFS (network), Ramdisk 
(Read-Only), and JFFS2 (Read/Write)
That's incorrect, either. A ramdisk is usually writable (unless you
mount it read-only, which would be very unusuak).

See also
http://www.denx.de/wiki/view/DULG/RootFileSystemDesignAndBuilding

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
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