Usage of MTD_UADDR_UNNECESSARY broken?

[Thayne Harbaugh]

On Mon, 2004-11-08 at 12:54 +0100, Alexander Hoffmann wrote:
> Hi everyone,
> 
> can anybody please explain me the exact difference between 
> MTD_UADDR_DONT_CARE and MTD_UADDR_UNNECESSARY .

It's exactly what the comments state:

	MTD_UADDR_DONT_CARE,		/* Requires an arbitrary address */
	MTD_UADDR_UNNECESSARY,		/* Does not require any address */


> Because if I use MTD_UADDR_UNNECESSARY an not existing field in the 
> unlock_addrs array is beeing referenced
> (/drivers/mtd/chips/jedec_probe.c, function cfi_jedec_setup, line 1740):

Unlock addresses shouldn't be assigned if they aren't necessary - hence
why there isn't an entry for them in unlock_addrs[].  There should be
logic that checks this before making the assignment.  Of course another
way to do it would be to have an entry assigned, but not use it.  I
prefer, however, that things break when the logic is incorrect - which
is the way it is now.

> /* Mask out address bits which are smaller than the device type */
> mask = ~(p_cfi->device_type-1);
> p_cfi->addr_unlock1 = unlock_addrs[uaddr].addr1 & mask;
> p_cfi->addr_unlock2 = unlock_addrs[uaddr].addr2 & mask;
> 
> If I change MTD_UADDR_DONT_CARE to MTD_UADDR_UNNECESSARY everything 
> works fine!

Apparently there is a problem that it isn't exiting the function earlier
for the MTD_UADDR_UNNECESSARY case.

Of course you also need to know which kind of chip you have: Is it a
DONT_CARE or an UNNECESSARY?

-- 
Thayne Harbaugh
Linux Networx
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