Hello Wolfgang,
On Friday 14 July 2006 10:28, Wolfgang Denk wrote:
in message 200607140914.07427.sr@denx.de you wrote:
I am "voting" for David's implementation, since bad blocks are "normal" on NAND chips. And if I remember correctly, the "old" U-Boot NAND driver also just skipped the bad block upon erasing without reproting them.
I'm sorry, but I disagree. This code is not coming out of thin air. It is a more or less vrbatim copy of the corresponding Linux MTD NAND code, see "drivers/mtd/nand/nand_base.c" in your Linux kernel tree.
In U-Boot, we have the additional #define NAND_ALLOW_ERASE_ALL which can be enabled if you don't like this behaviour.
If you believe that the U-Boot behavious is wrong, then the Linux MTD driver would be wrong, too. In this case discussion should continue on the MTD mailing list.
I find it hard to believe that a linux NAND erase operation will stop upon reaching a bad block. But you are right: the code in question is the same in the current linux mtd driver. From my experience, I never had problems erasing NAND flash devices (from U-Boot & linux) which had bad blocks.
As long as I don't see any changes to the current MTD Linux code you will need really good arguments to talk me into changing the U-Boot code.
I see. You have a good point here. This needs some testing on a device with bad blocks. "Unfortunately" the device on my desk has no bad blocks at all:
=> nand bad
Device 0 bad blocks:
Perhaps somebody else can jump in here and test the current linux mtd driver behavior on a device with bad blocks. Thanks.
Best regards, Stefan