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

[Marek Vasut <marex@denx.de>]

Dear Gachet Daniel,

> Hi Stefano and Marek,
> 
> -----Original Message-----
> From: stefano babic [mailto:sbabic at denx.de]
> Sent: dimanche 1 avril 2012 12:33
> To: Gachet Daniel
> Cc: u-boot at lists.denx.de
> Subject: Re: [U-Boot] [PATCH] Correct corrupted NAND Flash access on KARO
> TX25 modules
> 
> >Am 31/03/2012 09:31, schrieb 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@hefr.ch>
> >> Cc: Wolfgang Denk <wd@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
> >
> >NAK. We cleaned up all u-boot occurrencies of machine id, except the
> >machid passed to the kernel. And when the device tree will be effective,
> >also the machid will be obsolete.
> >
> >This change seems not strictly related to the Karo's SOM, but it it a
> >configuration of the mxc_nand driver, such as CONFIG_NAND_MXC_V1_1. You
> >can add a CONFIG_NAND_MXC_* value (please add documentation, too) and use
> >it in the driver code.
> >
> >Can I also ask you if the same setup is used in the Linux driver (this SOM
> >is not mainlined, I suppose you have a porting from the manufacturer) ?
> >As far as I can see, this setup is not used for the Freescale's mx25pdk
> >(the only MX25 board in mainline kernel).
> >
> >Best regards,
> >Stefano Babic
> >
> >--
> >=====================================================================
> >DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
> >HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> >Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
> >=====================================================================
> 
> I found the proposition of Stefano very interesting. My proposition will be
> to define a specific value for that bit, for instance
> CONFIG_NAND_MXC_V1_1_NFC_ONE_CYCLE. If this value is defined, the
> NFC_ONE_CYCLE bit will be set, otherwise not. This value could be defined
> in the specific board configuration file (./include/configs/...).
> 
> The patch will be the following:
> 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	2012-04-01 21:07:13.000000000 +0200
> @@ -1290,7 +1290,9 @@ static void mxc_setup_config1(void)
>  	uint16_t tmp;
> 
>  	tmp = readw(&host->regs->nfc_config1);
> +#ifdef CONFIG_NAND_MXC_V1_1_NFC_ONE_CYCLE
>  	tmp |= NFC_ONE_CYCLE;
> +#endif
>  	tmp |= NFC_4_8N_ECC;
>  	writew(tmp, &host->regs->nfc_config1);
>  	if (host->pagesize_2k)
> 
> Is that a valuable solution for you?

Ain't that basically what I said? Though, I might have not been clear enough ;-) 
Yes, that's it. Thanks!

> 
> Cordially,
> 
> Daniel