[PATCH] OneNAND: Runtime badblock check support

Kyungmin Park kmpark at infradead.org
Wed Jul 22 03:59:51 EDT 2009

On Wed, Jul 22, 2009 at 4:28 PM, Artem Bityutskiy<dedekind1 at gmail.com> wrote:
> On 07/22/2009 10:11 AM, Kyungmin Park wrote:
>> It don't avoid the double-scanning issue. only partial scan at
>> bootloader. In my environemt kernel has 2MiB partition and we only
>> scan this partition at load kernel command.
>> Exactly that it skip the bad block scanning except the kernel
>> partition at bootloader
>> As bootcmd load kernel, it first check that read block is bad, if not
>> read this block, next check again next block, and read next block and
>> so on.
> So you have a small kernel partition, you store the kernel there.
> Your boot-loader reads the kernel partition and loads the kernel
> from there. And of course the boot-loader scans the kernel partition
> for bad block. And your boot-loader does not need to scan anything
> else. I understand this part.


> But what is next? Do you want to tell the kernel to avoid scanning the
> kernel partition because boot-loader has already scanned it? Sorry, I
> still cannot get the idea...

Kernel part is same as before. Now I just optimize the boot loader part.

>> I don't have any idea about on-flash BBT.
> It is standard mechanism which exists in MTD from early tglx1 times.
> MTD can keep BBT on flash, AFAIR, in the last eraseblock. Look for the
> NAND_USE_FLASH_BBT constant. And this is the way to go if you want to
> optimize BBT scanning, IMO.

Yes I know, I mean no plan to implement it now. Sorry

Thank you,
Kyungmin Park

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