[U-Boot] NAND crazy behavior - mtd->size changing without clear reason

[Otavio Salvador]

On Wed, Sep 25, 2013 at 8:56 PM, Scott Wood <scottwood at freescale.com> wrote:
> On Wed, 2013-09-25 at 20:52 -0300, Otavio Salvador wrote:
>> On Wed, Sep 25, 2013 at 8:07 PM, Scott Wood <scottwood at freescale.com> wrote:
>> > On Wed, 2013-09-25 at 09:26 -0300, Otavio Salvador wrote:
>> >> Hello,
>> >>
>> >> I am using a K9LBG08U0D-PCB0 NAND IC with the i.MX28EVK board.
>> >>
>> >> I tested it with 2013.04 and current imx tree tip. Both same results.
>> >>
>> >> I am having problems to use mtdparts with it as it thinks the NAND has
>> >> size as 0 when it gets there. /However/ it properly detects it
>> >> initially and the mtd->size variable is magically changes on the fly.
>> >>
>> >> I added following patch in my local tree to debug the issue:
>> >>
>> >> diff --git a/drivers/mtd/nand/nand.c b/drivers/mtd/nand/nand.c
>> >> index 4cf4c1c..03faf10 100644
>> >> --- a/drivers/mtd/nand/nand.c
>> >> +++ b/drivers/mtd/nand/nand.c
>> >> @@ -66,11 +66,14 @@ int nand_register(int devnum)
>> >>         add_mtd_device(mtd);
>> >>  #endif
>> >>
>> >> +       printf("%s (%d) mtd->size: %d\n", __FUNCTION__, __LINE__, mtd->size);
>> >>         total_nand_size += mtd->size / 1024;
>> >> +       printf("%s (%d) mtd->size: %d\n", __FUNCTION__, __LINE__, mtd->size);
>> >
>> > Pay attention to compiler warnings...  mtd->size is uint64_t.
>>
>> Great but this does not explain the value changing, does it?
>
> Sure it does.  You're passing a 64-bit value as the fourth argument.
> Since IIRC there are only four registers used for passing parameters on
> 32-bit ARM, this will move the value to the stack.  You told printf that
> it was a 32-bit parameter, so printf is looking in r3 which contains
> random junk.

I see; I will check all this tomorrow :-)

Thanks for the hint.

-- 
Otavio Salvador                             O.S. Systems
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