Re: [PATCH] Add 'config IMX_NFC_V1_BISWAP' to swap the Bad block Indicator, and use for imx27pdk nand support.

["Lambrecht Jürgen" <J.Lambrecht@TELEVIC.com>]

On 07/06/2011 10:09 AM, Sascha Hauer wrote:
>
> On Tue, Jul 05, 2011 at 03:33:48PM +0200, Jürgen Lambrecht wrote:
> > - Swap the BI-byte on position 0x7D0 with a data byte at 0x835.  To 
> fix a bug
> >   in Freescale imx NFC v1 SoC's for 2K page NAND flashes: imx27 and 
> imx31.
> >   Warning: The same solution needs to be applied to the boot loader 
> and the
> >   flash programmer.
> > - Enable NAND support for the imx27pdk (3ds), and use BISWAP.
> >
> > Signed-off-by: Jürgen Lambrecht <J.Lambrecht@televic.com>
> > ---
> >  arch/arm/mach-imx/Kconfig         |   30 ++++++++++++++++++++++++++++--
> >  arch/arm/mach-imx/mach-mx27_3ds.c |   14 ++++++++++++++
> >  drivers/mtd/nand/mxc_nand.c       |   29 +++++++++++++++++++++++++++++
> >  3 files changed, 71 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
> > index 0519dd7..e8b16a9 100644
> > --- a/arch/arm/mach-imx/Kconfig
> > +++ b/arch/arm/mach-imx/Kconfig
> > @@ -274,7 +274,7 @@ config MACH_EUKREA_MBIMX27_BASEBOARD
> >  endchoice
> >
> >  config MACH_MX27_3DS
> > -     bool "MX27PDK platform"
> > +     bool "MX27PDK (3DS) platform"
> >       select SOC_IMX27
> >       select IMX_HAVE_PLATFORM_FSL_USB2_UDC
> >       select IMX_HAVE_PLATFORM_IMX2_WDT
> > @@ -284,13 +284,39 @@ config MACH_MX27_3DS
> >       select IMX_HAVE_PLATFORM_IMX_UART
> >       select IMX_HAVE_PLATFORM_MXC_EHCI
> >       select IMX_HAVE_PLATFORM_MXC_MMC
> > +     select IMX_HAVE_PLATFORM_MXC_NAND
> >       select IMX_HAVE_PLATFORM_SPI_IMX
> >       select MXC_DEBUG_BOARD
> >       select MXC_ULPI if USB_ULPI
> >       help
> > -       Include support for MX27PDK platform. This includes specific
> > +       Include support for MX27PDK (3DS) platform. This includes 
> specific
> >         configurations for the board and its peripherals.
> >
> > +config MACH_MXC_NAND_USE_BBT
> > +     bool "Make the MXC NAND driver use the in flash Bad Block Table"
> > +     depends on MACH_MX27_3DS
> > +     depends on MTD_NAND_MXC
> > +     help
> > +       Enable this if you want that the MXC NAND driver uses the in 
> flash
> > +       Bad Block Table to know what blocks are bad instead of 
> scanning the
> > +       entire flash looking for bad block markers.
>
> Besides the fact that we have too many kconfig options there's another
> problem. We try to build kernels which run on as many boards as
> possible. Adding options like this limit a kernel for a particular
> usecase (bbt vs. scanning)
>
Indeed. I just copied it from MACH_MX31_3DS_MXC_NAND_USE_BBT, and 
thought it was good to do the same.
If I want to use it, better just do it without that option, as other 
_3ds boards do (and davinci and atmel also do in another way).
I will remove the option in a separate nand patch for imx27pdk.

Regards,
Jürgen
[snip]