From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?utf-8?Q?Beno=C3=AEt_Th=C3=A9baudeau?= <benoit.thebaudeau@advansee.com>
Date: Wed, 27 Feb 2013 13:53:10 +0100 (CET)
Subject: [U-Boot] [PATCH v2 2/2] mtd: nand: mxc_nand: Fix is_16bit_nand()
In-Reply-To: <20130227121104.15c16b00@e6520eb>
References: <1361903720-26935-1-git-send-email-fabio.estevam@freescale.com>
	<1361903720-26935-2-git-send-email-fabio.estevam@freescale.com>
	<20130227121104.15c16b00@e6520eb>
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To: u-boot@lists.denx.de

Hi Eric,

On Wednesday, February 27, 2013 12:11:04 PM, Eric B?nard wrote:
> Hi Fabio,
> 
> Le Tue, 26 Feb 2013 15:35:20 -0300,
> Fabio Estevam <fabio.estevam@freescale.com> a ?crit :
> 
> > Currently is_16bit_nand() is a per SoC function and it decides the bus nand
> > width by reading some boot related registers.
> > 
> > This method works when NAND is the boot medium, but does not work if
> > another
> > boot medium is used. For example: booting from a SD card and then using
> > NAND
> > to store the environment variables, would lead to the following error:
> > 
> > NAND bus width 16 instead 8 bit
> > No NAND device found!!!
> > 0 MiB
> > 
> > Use CONFIG_SYS_NAND_BUSWIDTH_16BIT symbol to decide the bus width.
> > 
> > If it is defined in the board file, then consider 16-bit NAND bus-width,
> > otherwise assume 8-bit NAND is used.
> > 
> > This also aligns with Documentation/devicetree/bindings/mtd/nand.txt, which
> > states:
> > 
> > nand-bus-width : 8 or 16 bus width if not present 82
> > 
> are you sure that your patch won't break current boards booting on nand
> flash (and so which can use the current functions to detect the nand
> width) ?

This code is not used for NAND boot, for which the SPL version of this driver
and CONFIG_SYS_NAND_BUSWIDTH_16 are used.

Best regards,
Beno?t