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From: "Benoît Thébaudeau" <benoit.thebaudeau@advansee.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH v2 2/2] mtd: nand: mxc_nand: Fix is_16bit_nand()
Date: Wed, 27 Feb 2013 13:53:10 +0100 (CET)	[thread overview]
Message-ID: <1701948647.144167.1361969590454.JavaMail.root@advansee.com> (raw)
In-Reply-To: <20130227121104.15c16b00@e6520eb>

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

  reply	other threads:[~2013-02-27 12:53 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-26 18:35 [U-Boot] [PATCH v2 1/2] mtd: nand: Introduce CONFIG_SYS_NAND_BUSWIDTH_16BIT Fabio Estevam
2013-02-26 18:35 ` [U-Boot] [PATCH v2 2/2] mtd: nand: mxc_nand: Fix is_16bit_nand() Fabio Estevam
2013-02-26 18:47   ` Benoît Thébaudeau
2013-02-26 19:11     ` Fabio Estevam
2013-02-27 11:11   ` Eric Bénard
2013-02-27 12:53     ` Benoît Thébaudeau [this message]
2013-02-27 13:15       ` Eric Bénard
2013-02-27 13:40         ` Benoît Thébaudeau
2013-02-27 17:18           ` Eric Bénard
2013-02-27 13:16     ` Fabio Estevam

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