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

["Benoît Thébaudeau" <benoit.thebaudeau@advansee.com>]

Dear Marek Vasut,

On Monday, February 25, 2013 10:09:07 PM, Marek Vasut wrote:
> Dear Beno?t Th?baudeau,
> 
> > 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@denx.de>
> > > Cc: Beno?t Th?baudeau <benoit.thebaudeau@advansee.com>
> > > Cc: Fabio Estevam <fabio.estevam@freescale.com>
> > > Cc: Stefano Babic <sbabic@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?
> 
> That's all for now, that's how it boots and how others do it as well. In the
> long run though, I'd prefer to bend mxsboot to generate the DBBT.

After a quick look at mxsboot, it seems to just generate an empty DBBT, so this
does not help for boot reliability.

> > 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,
Beno?t