[U-Boot] [PATCH] Correct corrupted NAND Flash access on KARO TX25 modules

[Marek Vasut]

Dear Gachet Daniel,

> Dear Marek,
> 
> >Dear Gachet Daniel,
> >
> >> This short patch correct corrupted data while reading NAND flash
> >> modules on the KARO TX25 module.
> >> 
> >> The current version of the mxc_nand driver uses the symmetric mode to
> >> access the NAND flash, but the devices populated on the KARO TX25 only
> >> support an asymmetric mode (i.MX25: bit 8  within NAND_FLASH_CONFIG1
> >> register cleared).
> >> 
> >> Signed-off-by: Daniel Gachet <daniel.gachet at hefr.ch>>
> >> Cc: Wolfgang Denk <wd at denx.de >>
> >> 
> >> diff -upr drivers/mtd/nand/mxc_nand.c drivers/mtd/nand/mxc_nand.c
> >> --- drivers/mtd/nand/mxc_nand.c	2011-12-23 20:25:35.000000000 +0100
> >> +++ drivers/mtd/nand/mxc_nand.c	2012-03-30 08:10:13.000000000 +0200
> >> @@ -1290,7 +1290,9 @@ static void mxc_setup_config1(void)
> >> 
> >>  	uint16_t tmp;
> >>  	
> >>  	tmp = readw(&host->>regs->>nfc_config1);
> >> 
> >> +#ifndef MACH_TYPE_TX25
> >> 
> >>  	tmp |= NFC_ONE_CYCLE;
> >> 
> >> +#endif
> >> 
> >>  	tmp |= NFC_4_8N_ECC;
> >>  	writew(tmp, &host->>regs->>nfc_config1);
> >>  	if (host->>pagesize_2k)
> >
> >Won't it be better to make this more generic rather then adding more
> >machine- specific hacks please?
> >
> >Best regards,
> >Marek Vasut
> 
> It's really a good question.
> 
> This modification should probably work on other i.MX25 boards, because it
> relaxes the timing while accessing the NAND flash. But unfortunately I
> haven't other i.MX25 boards on which I can verify this modification.  Do
> you have other modules to validate this modification?

Not yet, but if you have one, you can do it in a generic way and if another one 
pops up, we can simply use it :)

> Cordially,
> 
> Daniel

Best regards,
Marek Vasut