[U-Boot] [PATCH 1/4] common: imx: Implement generic u-boot.nand target

[Benoît Thébaudeau]

Dear Marek Vasut,

On Monday, February 25, 2013 7:19:54 PM, Marek Vasut wrote:
> Implement u-boot.nand target that can be reused with a small amount of
> churn across all CPU models. The idea is to delegate the u-boot.nand target
> out of the main Makefile and into the CPU's Makefile (very similar to what
> u-boot.imx does now). The main Makefile shall only contain path to which the
> u-boot.nand target is delegated. Hopefully this will not produce too much
> bloat in the main Makefile.
> 
> To demonstrate this implementation, add u-boot.nand target for i.MX53.
> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Benoît Thébaudeau <benoit.thebaudeau at advansee.com>
> Cc: Fabio Estevam <fabio.estevam at freescale.com>
> Cc: Stefano Babic <sbabic at denx.de>
> ---
>  Makefile                     |   18 ++++++++++++++++++
>  arch/arm/imx-common/Makefile |    6 ++++++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/Makefile b/Makefile
> index 41054b7..8b1010a 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -470,6 +470,23 @@ $(obj)u-boot.img:	$(obj)u-boot.bin
>  $(obj)u-boot.imx: $(obj)u-boot.bin depend
>  		$(MAKE) -C $(SRCTREE)/arch/arm/imx-common $(obj)u-boot.imx
>  
> +#
> +# Generic u-boot.nand target.
> +#
> +# Every CPU that needs u-boot.nand must add a path to an implementation of
> +# the actual u-boot.nand generator below.
> +#
> +ifdef CONFIG_MX53
> +CONFIG_NAND_TRG_PATH := $(SRCTREE)/arch/arm/imx-common

What about calling it rather CONFIG_NAND_TGT_PATH? TRG looks more like trigger.

> +endif
> +
> +$(obj)u-boot.nand: $(obj)u-boot.bin depend
                                       ^
$(obj)u-boot.bin already depends on depend through $(obj)u-boot, so it's useless
here.

> +		if [ "X$(CONFIG_NAND_TRG_PATH)X" = "XX" ] ; then		\
> +			echo "This CPU does not support u-boot.nand target!" ;	\
> +			exit 1 ;						\
> +		fi
> +		$(MAKE) -C $(CONFIG_NAND_TRG_PATH) $(obj)u-boot.nand
                                                   ^
                                                   $(OBJTREE)/

> +
>  $(obj)u-boot.kwb:       $(obj)u-boot.bin
>  		$(obj)tools/mkimage -n $(CONFIG_SYS_KWD_CONFIG) -T kwbimage \
>  		-a $(CONFIG_SYS_TEXT_BASE) -e $(CONFIG_SYS_TEXT_BASE) -d $< $@
> @@ -857,6 +874,7 @@ clobber:	tidy
>  	@rm -f $(obj)u-boot.kwb
>  	@rm -f $(obj)u-boot.pbl
>  	@rm -f $(obj)u-boot.imx
> +	@rm -f $(obj)u-boot.nand
>  	@rm -f $(obj)u-boot.ubl
>  	@rm -f $(obj)u-boot.ais
>  	@rm -f $(obj)u-boot.dtb
> diff --git a/arch/arm/imx-common/Makefile b/arch/arm/imx-common/Makefile
> index 5d5c5b2..71ea36f 100644
> --- a/arch/arm/imx-common/Makefile
> +++ b/arch/arm/imx-common/Makefile
> @@ -50,6 +50,12 @@ $(obj)u-boot.imx: $(OBJTREE)/u-boot.bin
> $(OBJTREE)/$(patsubst "%",%,$(CONFIG_IMX
>  	$(OBJTREE)/tools/mkimage -n $(filter-out %.bin,$^) -T imximage \
>  	-e $(CONFIG_SYS_TEXT_BASE) -d $< $@
>  
> +$(obj)u-boot.nand: $(obj)u-boot.imx
> +	(								\
> +		echo -ne '\x00\x00\x00\x00\x46\x43\x42\x20\x01' ;	\
> +		dd if=/dev/zero bs=1015 count=1 2>/dev/null ) |		\
> +	cat - $< > $@

Is that all? According to 7.5.2.2 (i.MX53 RM), the boot ROM switches to serial
mode if anything goes wrong with the NAND. Hence, for reliable NAND boot, you
have to choose either DBBT or SPL (or both, but that would be waste).

Populating the DBBT would be complicated, so I'd go for SPL. You could just use
my u-boot-with-nand-spl.imx and change the dummy header to a true FCB with the
fingerprint like you did in your header above. u-boot.nand then becomes useless.

> +
>  $(obj)SPL: $(OBJTREE)/spl/u-boot-spl.bin $(OBJTREE)/$(patsubst
>  "%",%,$(CONFIG_IMX_CONFIG)).cfgtmp
>  	$(OBJTREE)/tools/mkimage -n $(filter-out %.bin,$^) -T imximage \
>  	-e $(CONFIG_SPL_TEXT_BASE) -d $< $@


Best regards,
Benoît