[U-Boot-Users] NAND "bad block" support
how does the U-Boot solve the "bad block" problem in the NAND flash memory? 1) does the U-Boot have support to 'bad-block table'? If it does, then how do I activate it? 2) does the U-Boot work with JFFS2 (that handles 'bad blocks')?
Sincerely Shai Lifshitz
On Sunday 05 August 2007, Shai Lifshitz wrote:
how does the U-Boot solve the "bad block" problem in the NAND flash memory?
Yes, U-Boot NAND driver is bad block aware (would be worthless without).
- does the U-Boot have support to 'bad-block table'? If it does, then how
do I activate it?
No, the bad-block-table is not supported right now. Would be nice extension though.
- does the U-Boot work with JFFS2 (that handles 'bad blocks')?
Yes.
Best regards, Stefan
===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: office@denx.de =====================================================================
Hi Stefan
Thanks for your answer
I am planning to use the U-Boot to load the Linux operating system that is stored on a NAND flash.
The UBoot main role (beside other tasks) is to load the linux kernel and file-system from the NAND flash to the RAM, and start the linux. Another role of UBoot is to get the kernel and file-system from the ethernet, and burn it to the NAND flash.
What is the preferred way to treat the "bad block" problem in writing (not writing to bad blocks, and checking the status after programming/erasing) and reading (jumping over bad blocks).
1) Does normal read/write coop with these issues?
2) In the NAND documentation it says that the "shipped bad blocks" have to be checked prior to any erase operations. Does the UBoot leave the bad blocks untouched during the erase operation?
3) Do you recommend to use JFFS2 file-system just to save/read the kernel/file-system images?
Sincerely
Shai Lifshitz email: shail@visonic.com
Stefan Roese sr@denx.de Sent by: u-boot-users-bounces@lists.sourceforge.net 08/06/2007 02:12 PM
To: u-boot-users@lists.sourceforge.net cc: Shai Lifshitz ShaiL@visonic.com Subject: Re: [U-Boot-Users] NAND "bad block" support
On Sunday 05 August 2007, Shai Lifshitz wrote:
how does the U-Boot solve the "bad block" problem in the NAND flash memory?
Yes, U-Boot NAND driver is bad block aware (would be worthless without).
- does the U-Boot have support to 'bad-block table'? If it does, then
how
do I activate it?
No, the bad-block-table is not supported right now. Would be nice extension though.
- does the U-Boot work with JFFS2 (that handles 'bad blocks')?
Yes.
Best regards, Stefan
===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: office@denx.de =====================================================================
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Hi Shai,
On Monday 06 August 2007, Shai Lifshitz wrote:
I am planning to use the U-Boot to load the Linux operating system that is stored on a NAND flash.
The UBoot main role (beside other tasks) is to load the linux kernel and file-system from the NAND flash to the RAM, and start the linux. Another role of UBoot is to get the kernel and file-system from the ethernet, and burn it to the NAND flash.
OK, that's what U-Boot is designed for.
What is the preferred way to treat the "bad block" problem in writing (not writing to bad blocks, and checking the status after programming/erasing) and reading (jumping over bad blocks).
- Does normal read/write coop with these issues?
Yes.
- In the NAND documentation it says that the "shipped bad blocks" have to
be checked prior to any erase operations. Does the UBoot leave the bad blocks untouched during the erase operation?
Yes.
- Do you recommend to use JFFS2 file-system just to save/read the
kernel/file-system images?
The kernel doesn't need to be saved in a filesystem at all. I would reserve one flash partition for it and read/write it from there. Some goes for the root filesystem if you don't have to write to it from Linux. You could use cramfs, romfs, initrd etc.
BTW: Please note that U-Boot "only" supports JFFS2 read operations. For writing to NAND (and NOR...) you will have to write raw data to the chip. But that's what the interface is designed for and what is already working in lots of projects.
Best regards, Stefan
===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: office@denx.de =====================================================================
participants (2)
-
Shai Lifshitz -
Stefan Roese