[U-Boot] [PATCH] mtest: Fix end address of increment/decrement test

[Wolfgang Denk]

Dear Peter Tyser,

In message <1274382441.18152.37.camel at petert> you wrote:
> 
> I can see your point but the current memtest code is not consistent with
> your description.
> - Every other test other than the increment/decrement tests the region <
> end address.  Eg in the start:0x1000 end:0x2000 example, the *only* test
> that touches 0x2000-0x2003 region is the increment/decrement test.
> Either its broken, or the other memory test functions are.

I think this might indeed be the case. IIRC I originally wrote only
the simple increment/decrement test, and the other tests got added
later by others, probably with nobody noticing the differing
behaviour.

> - The output of 'mtest' is misleading:
> => mtest 0x1000 0x2000 1 1
> Testing 00001000 ... 00002000:
> 
> That should be "00001000 ... 00002003" then, correct?  (I know it should

No, it should not. The output shows the addresses where data is
written to. If you write a 32 bit word to address 00002000, this
writes to the byte addresses 00002000, 00002001, 00002002 and
00002003 (assuming a big endian system). So the output actually is
correct.

> be "00001000 ... 00001fff" to be consistent with this patch's
> implementation, so this argument is weak...)

No, because we do not actually write to this address (which would also
be misaligned for a word write).

> How would you like this cleaned up?  Bring the address coverage of the
> other tests inline with the increment/decrement test?  Improve the mtest
> output so its obvious what exactly is being tested?

Both, of course :-)  Although I think the output is even correct, it
just leaves room for misinterpretation.

Best regards,

Wolfgang Denk

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