erase questions

erase questions

[Abraham vd Merwe]

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Hi!

I have a couple of questions about mtd_info->erase which isn't covered in
the MTD API:

From the MTD API docs, it seems the erase function can only be called
erase_info->len == mtd->erasesize. This is obviously not true anymore since
there can be multiple erase regions with multiple erase sizes and the user
might request an erase on one of the smaller blocks.

So can I assume that I only have to deal (read: allow) with erases where
erase_info->addr == START_OF_SOME_BLOCK and erase_info->len ==
LENGTH_OF_THAT_BLOCK?

So basically it boils down to 2 questions. Is ->addr always equal to the
start of a block and is ->len always equal to the size of that block or may
->len span multiple blocks.

If ->len may span multiple blocks, must it be equal to the size of all the
blocks (e.g. if you we're to erase a 2x 4k + 3x 8k consecutive blocks, must
len be equal to 32k)?

-- 

Regards
 Abraham

Reading is to the mind what exercise is to the body.

__________________________________________________________
 Abraham vd Merwe - 2d3D, Inc.

 Device Driver Development, Outsourcing, Embedded Systems

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Re: erase questions

[David Woodhouse]

abraham@2d3d.co.za said:
>  If ->len may span multiple blocks, must it be equal to the size of
> all the blocks (e.g. if you we're to erase a 2x 4k + 3x 8k consecutive
> blocks, must len be equal to 32k)?

The only constraints are that both <start> and <start+len> must be aligned 
with erase block boundaries.

If you have a chip with 8*8K erase blocks followed by 15*64K erase blocks, 
then an erase of length 72K at offset 56K is permitted - you'd erase the 
last of the small blocks and the first of the big blocks.

--
dwmw2