How can I make flash writeable?

[Duy-Ky Nguyen]

Dear Wolfgang Denk,

I totally agree ramdisk filesystem is writable. However, for this particular 
MPC8313E-RDB with FreeScale BSP Linux via LTIB (Linux Traget Image Builder), 
based on the BSP document, I did try ramdisk and unable to save change after 
power recycle. That's why I had to try JFFS2 and it did save my change after 
power recycle .

It's even more confusing when I tried to recreate ramdisk image using LTIB 
and found ramdisk is of type EXT2, which is writable filesystem !?!?

Best Regards,

Duy-Ky

----- Original Message ----- 
From: <linuxppc-embedded-request at ozlabs.org>
To: <linuxppc-embedded at ozlabs.org>
Sent: Saturday, October 18, 2008 6:00 PM
Subject: Linuxppc-embedded Digest, Vol 50, Issue 31


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> Today's Topics:
>
>   1. Re: How can I make flash writeable? (Duy-Ky Nguyen)
>   2. Re: Cache control (Grant Likely)
>   3. Re: How can I make flash writeable? (Wolfgang Denk)
>   4. Related to Keypad Driver .... (Misbah khan)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 17 Oct 2008 18:19:38 -0700
> From: "Duy-Ky Nguyen" <duykynguyen at hotmail.com>
> Subject: Re: How can I make flash writeable?
> To: <linuxppc-embedded at ozlabs.org>
> Message-ID: <BLU119-DAV13B797B2CC811E90F87406BB2D0 at phx.gbl>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> 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 ----- 
> From: <linuxppc-embedded-request at ozlabs.org>
> To: <linuxppc-embedded at ozlabs.org>
> Sent: Friday, October 17, 2008 6:00 PM
> Subject: Linuxppc-embedded Digest, Vol 50, Issue 30
>
>
>> Send Linuxppc-embedded mailing list submissions to
>> linuxppc-embedded at ozlabs.org
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>> or, via email, send a message with subject or body 'help' to
>> linuxppc-embedded-request at ozlabs.org
>>
>> You can reach the person managing the list at
>> linuxppc-embedded-owner at ozlabs.org
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of Linuxppc-embedded digest..."
>>
>>
>> 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 <mark at bish.net>
>> Subject: Re: How can I make flash writeable?
>> To: linuxppc-embedded at ozlabs.org
>> Message-ID: <20081017083352.hvn0g2q1es8skcwg at www.bish.net>
>> 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 <marco.stornelli at coritel.it>:
>>
>>> Hi Mark,
>>>
>>>> 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:
>>>> 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 at 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 at coritel.it
>>> +39 06 72582838
>>>
>>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Fri, 17 Oct 2008 15:13:58 +0200
>> From: Marco Stornelli <marco.stornelli at coritel.it>
>> Subject: Re: How can I make flash writeable?
>> To: Mark Bishop <mark at bish.net>
>> Cc: linuxppc-embedded at ozlabs.org
>> Message-ID: <48F88F96.3000804 at coritel.it>
>> 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:
>>>
>>>
>>> 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 <marco.stornelli at coritel.it>:
>>>
>>>> Hi Mark,
>>>>
>>>>> 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:
>>>>> 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 at 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 at coritel.it
>>>> +39 06 72582838
>>>>
>>>>
>>>
>>> _______________________________________________
>>> Linuxppc-embedded mailing list
>>> Linuxppc-embedded at 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 at coritel.it
>> +39 06 72582838
>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Fri, 17 Oct 2008 09:12:07 -0400
>> From: Ben Gardiner <BenGardiner at nanometrics.ca>
>> Subject: Re: Loadable module crashes at kernel stack overflow or
>> machine check
>> To: Ganesh Kumar N M <ganeshkumar at signal-networks.com>
>> Cc: linuxppc-dev at ozlabs.org, linuxppc-embedded at ozlabs.org
>> Message-ID: <48F88F27.4040107 at nanometrics.ca>
>> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
>>
>> Ganesh Kumar N M wrote:
>>> *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
>> -------------- next part --------------
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>>
>> ------------------------------
>>
>> Message: 4
>> Date: Fri, 17 Oct 2008 10:21:32 -0500
>> From: Scott Wood <scottwood at freescale.com>
>> Subject: Re: Oops in during system run
>> To: Sreejith <sreejithmm at tataelxsi.co.in>
>> Cc: linuxppc-dev at ozlabs.org, linuxppc-embedded at ozlabs.org
>> Message-ID: <20081017152129.GA19584 at ld0162-tx32.am.freescale.net>
>> Content-Type: text/plain; charset=us-ascii
>>
>> On Fri, Oct 17, 2008 at 03:49:12PM +0530, Sreejith wrote:
>>> This is a peculiar Oops we are encountering during the running of our
>>> board
>>> (sh4) architecture
>>
>> So why are you posting to powerpc lists?
>>
>>> PC  : 844240f8 SP  : 88d1ff44 SR  : 400080f0 TEA : c0169d64    Tainted: 
>>> P
>>
>> With proprietary modules, too.
>>
>>> Give you valuable suggestions!!
>>
>> Debug the code?
>> Switch to powerpc? :-)
>>
>> -Scott
>>
>>
>> ------------------------------
>>
>> _______________________________________________
>> Linuxppc-embedded mailing list
>> Linuxppc-embedded at ozlabs.org
>> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>>
>> End of Linuxppc-embedded Digest, Vol 50, Issue 30
>> *************************************************
>>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 18 Oct 2008 00:32:47 -0600
> From: Grant Likely <grant.likely at secretlab.ca>
> Subject: Re: Cache control
> To: Robert Woodworth <rwoodworth at securics.com>
> Cc: linuxppc-embedded <linuxppc-embedded at ozlabs.org>
> Message-ID: <20081018063246.GA5594 at secretlab.ca>
> Content-Type: text/plain; charset=us-ascii
>
> On Thu, Oct 16, 2008 at 09:57:27AM -0600, Robert Woodworth wrote:
>> I have a Virtex4 VF60 device with 256MB DDR2.
>>
>> I have told the Linux kernel that the device has only 128MB and its
>> working fine.  There is an HDL module that is populating the next 16MB
>> with sensor data (0x08000000 - 0x09000000)  I mapped the area into my
>> driver via `ioremap()` and also via `mmap / remap_pfn_range()`  It works
>> fine.
>>
>> I know that PPC cache regions work in 128MB blocks.  I assume that the
>> kernel bootup is turning on cache in the first 128, because it thinks
>> that its the full RAM range, and not cached in the next 128MB.
>
> That's only true when the MMU is off.  Linux runs with the MMU on and
> the TLB entries specify the caching per mapping.
>
>> I know that if I declare the area cached, and invalidate the region
>> before I read it,  the reads should be much faster than if it's not
>> cached.
>
> Correct.
>
>> How can I control if the area is cached? and then invalidate it when new
>> data arrives?
>>
>> Is there a PPC/Linux API call to declare the region cached and
>> invalidate regions before read?
>
> Take a look at dma_alloc_coherent() and related functions.
>
> Cheers,
> g.
>
>
>
> ------------------------------
>
> Message: 3
> Date: Sat, 18 Oct 2008 09:53:16 +0200
> From: Wolfgang Denk <wd at denx.de>
> Subject: Re: How can I make flash writeable?
> To: "Duy-Ky Nguyen" <duykynguyen at hotmail.com>
> Cc: linuxppc-embedded at ozlabs.org
> Message-ID: <20081018075316.11AB0835697A at gemini.denx.de>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Dear "Duy-Ky Nguyen",
>
> In message <BLU119-DAV13B797B2CC811E90F87406BB2D0 at phx.gbl> 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 at denx.de
> To get something done, a committee should consist  of  no  more  than
> three men, two of them absent.
>
>
> ------------------------------
>
> Message: 4
> Date: Sat, 18 Oct 2008 08:26:07 -0700 (PDT)
> From: Misbah khan <misbah_khan at engineer.com>
> Subject: Related to Keypad Driver ....
> To: linuxppc-embedded at ozlabs.org
> Message-ID: <20047836.post at talk.nabble.com>
> Content-Type: text/plain; charset=us-ascii
>
>
> Hi all ...
>
> If any of you have worked on key pad driver could you please guide me how 
> to
> write the same as in the most standard form ...
>
> I have a CPLD from Whre i have to read the key physical status (debouncing
> logic in CPLD itself) on interrupt this i have to pass to the application
> which ever is using keys for its operation and control ....
>
> The concern is this ...
>
>
> What could the best way of passing the virtual key status to the 
> application
> and how it is done in linux drivers ???? How should i make the API waiting
> for Key event and Getting Unblocked ???? Can i make the API as a thread
> waiting for signal ??? The same API application could use ... How is it 
> done
> in Standard Keyboard Drivers ???
>
> A code snipped or Documentation would really help me ...
>
>
> I am not sure what way i should proceed ...If any one implemented a Keypad
> driver or can suggest your experience
>
>
> Thanks in Advance ...
>
> Misbah <><
> -- 
> View this message in context: 
> http://www.nabble.com/Related-to-Keypad-Driver-....-tp20047836p20047836.html
> Sent from the linuxppc-embedded mailing list archive at Nabble.com.
>
>
>
> ------------------------------
>
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded at ozlabs.org
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>
> End of Linuxppc-embedded Digest, Vol 50, Issue 31
> *************************************************
>