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From: Marek Vasut <marek.vasut@gmail.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 5/5] NAND: Add scrub.quiet command option
Date: Wed, 14 Sep 2011 00:41:29 +0200	[thread overview]
Message-ID: <201109140041.30150.marek.vasut@gmail.com> (raw)
In-Reply-To: <4E6FD793.4010906@freescale.com>

[...]

> > ROM when loading firmware, copies back
> > the value at metadata[0] to BI offset in page data. The following figure
> > shows how the factory bad block marker is preserved.
> 
> ...this is insane.  It seems that they want you to swap this byte even
> in good blocks, so that you put the byte of real data that should go
> somewhere in the middle of the last 512-byte ECC chunk at offset zero in
> the page.  This means that it will show up as a bad block when normal
> (but new-layout-using) software looks at it, which is why you need
> scrub.  Ew.
> 
> How many blocks are being loaded by this mechanism?  Just block zero
> (which is normally supposed to be guaranteed good anyway...)?  Or
> multiple blocks?

The first block, then the 64th block, 128th block and 192th block (in default 
layout).
> 
> Any chance you could blow the NAND_MEMBLOCK_MARKER_RESERVE fuse? :-)

No, they are one-time programable. Delivering a "damaged" chip isn't a good 
practice.

> Otherwise, I guess you do need to scrub.  Have you complained to
> Freescale sales/support?

In fact no. The BootROM is "broken" and I doubt they will be willing to do 
anything about it.

> 
> > But we want to write a block in our own format, so we need to scrub (wipe
> > the block completely).
> 
> Erase always wipes the block completely, if it erases at all.  Scrub in
> this context just means that U-Boot ignores the bad block indications
> (marker or table).  Otherwise it would avoid erasing bad blocks, so that
> they stay bad, and you won't have scrubbed the entire region requested.
> 
> >> I work for the PowerPC side of Freescale, in case you're wondering why
> >> I'm unfamiliar with this. :-)
> > 
> > Interesting ... does everyone work for the PowerPC side of Freescale or
> > is there some other reason why I never met anyone working for the ARM
> > side of Freescale ? ;-)
> 
> They exist, but don't seem to engage Open Source development communities
> to the same degree.
> 
> -Scott

Cheers

  reply	other threads:[~2011-09-13 22:41 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-12  4:04 [U-Boot] [PATCH 0/5 V2] Random NAND fixes and improvements Marek Vasut
2011-09-12  4:04 ` [U-Boot] [PATCH 1/5] NAND: Really ignore bad blocks when scrubbing Marek Vasut
2011-09-27 18:54   ` Scott Wood
2011-09-12  4:04 ` [U-Boot] [PATCH 2/5] NAND: Add nand read.raw and write.raw commands Marek Vasut
2011-09-21 18:48   ` Scott Wood
2011-09-22  1:55   ` [U-Boot] [PATCH 2/5 V2] " Marek Vasut
2011-09-22 16:03     ` Scott Wood
2011-09-22 18:36     ` [U-Boot] [PATCH 2/5 V3] " Marek Vasut
2011-09-22 18:40       ` Scott Wood
2011-09-23 13:43       ` [U-Boot] [PATCH 2/5 V4] " Marek Vasut
2011-09-27 18:57         ` Scott Wood
2011-09-12  4:04 ` [U-Boot] [PATCH 3/5] NAND: Allow per-buffer allocation Marek Vasut
2011-09-21 18:50   ` Scott Wood
2011-09-21 19:49     ` Wolfgang Denk
2011-09-21 19:55       ` Scott Wood
2011-09-21 20:16         ` Wolfgang Denk
2011-09-22  1:34           ` Marek Vasut
2011-09-22  7:41           ` Stefano Babic
2011-09-22  8:51             ` Marek Vasut
2011-09-23 17:35               ` Scott Wood
2011-09-24 12:37                 ` Marek Vasut
2011-09-26 18:33                   ` Scott Wood
2011-09-26 18:49                     ` Marek Vasut
2011-09-12  4:04 ` [U-Boot] [PATCH 4/5] NAND: Make page, erase, oob size available via cmd_nand Marek Vasut
2011-09-21 18:55   ` Scott Wood
2011-09-21 19:52     ` Wolfgang Denk
2011-09-22  1:57   ` [U-Boot] [PATCH 4/5 V2] " Marek Vasut
2011-09-27 19:01     ` Scott Wood
2011-09-27 19:38       ` Marek Vasut
2011-09-27 19:51         ` Scott Wood
2011-09-27 20:07           ` Marek Vasut
2011-09-27 20:53             ` Scott Wood
2011-09-27 21:04               ` Marek Vasut
2011-09-27 21:14     ` Scott Wood
2011-09-12  4:04 ` [U-Boot] [PATCH 5/5] NAND: Add scrub.quiet command option Marek Vasut
2011-09-12 16:45   ` Mike Frysinger
2011-09-12 17:45     ` Marek Vasut
2011-09-12 18:06       ` Scott Wood
2011-09-12 18:24         ` Marek Vasut
2011-09-12 18:31           ` Scott Wood
2011-09-12 18:36             ` Marek Vasut
2011-09-12 19:19               ` Scott Wood
2011-09-12 19:28                 ` Marek Vasut
2011-09-12 19:36                   ` Scott Wood
2011-09-12 19:42                     ` Marek Vasut
2011-09-12 23:24                       ` Scott Wood
2011-09-13  1:02                         ` Marek Vasut
2011-09-13  4:25                           ` Wolfgang Denk
2011-09-13  4:36                             ` Marek Vasut
2011-09-13 22:22                           ` Scott Wood
2011-09-13 22:41                             ` Marek Vasut [this message]
2011-09-13 22:53                               ` Scott Wood
2011-09-12 18:37       ` Wolfgang Denk
2011-09-12 18:50         ` Marek Vasut
2011-09-12 20:33       ` Mike Frysinger
2011-09-12 22:59         ` Marek Vasut
2011-09-13 22:20   ` [U-Boot] [PATCH 5/5] NAND: Add -y option to nand scrub command Marek Vasut
2011-09-13 22:28     ` Mike Frysinger
2011-09-27 19:03     ` Scott Wood
  -- strict thread matches above, loose matches on Subject: below --
2011-09-08 20:39 [U-Boot] [PATCH 0/5] Random NAND fixes and improvements Marek Vasut
2011-09-08 20:39 ` [U-Boot] [PATCH 5/5] NAND: Add scrub.quiet command option Marek Vasut
2011-09-09 15:39   ` Detlev Zundel
2011-09-10 20:54     ` Marek Vasut
2011-09-12  9:49       ` Detlev Zundel

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