Unlocking with Intel J3 series flash

[Ralph Siemsen]

On Tue, Jul 31, 2007 at 05:23:31PM +0100, Ben Dooks wrote:
 
> My solution, which I can post the patch for, is to check the lock
> status of the page before trying to unlock the device.

In principle this sounds like a good idea, but we then trust the
device to give us status... wherease prevously the unlock command
would be issued regardless.  I wonder if there are any errata
regarding device status... probably... here is one:
http://download.intel.com/design/flcomp/applnots/30855503.pdf
although your code looks like it will deal correctly with this.

> +	/* check to see if the block is actually in the right state */
> +
> +	map_write(map, CMD(0x90), adr + (2 * ofs_factor));
> +	chip->state = FL_JEDEC_QUERY;

Ok.

> +	status = map_read(map, adr + (2 * ofs_factor));

Any reason you're not doing:
	 status = cfi_read_query(map, adr+(2*ofs_factor));
as is done in the do_printlockstatus_oneblock() function?

> +	/* return the chip to a state */
> +	map_write(map, CMD(0xf0), adr);
> +	map_write(map, CMD(0xff), adr);
> +
> +	chip->state = FL_READY;

That sequence worries me... I don't know enough about the state
machines in the MTD code to know if it safe to do this here...

The rest looks ok.

I do wonder if this should be done in cfi_cmdset_0001, or should 
it happen more globally?  Are there AMD chips with the same "feature"?

-R