[U-Boot] [PATCH] spl: make image arg or fdt blob address reconfigurable

[Vikas MANOCHA]

Hi Tom,

> -----Original Message-----
> From: Vikas MANOCHA
> Sent: Wednesday, April 12, 2017 12:47 PM
> To: 'Tom Rini' <trini at konsulko.com>
> Cc: u-boot at lists.denx.de; Marek Vasut <marex at denx.de>; Stefan Agner <stefan.agner at toradex.com>; Jeremy Hunt
> <Jeremy.Hunt at DEShawResearch.com>
> Subject: RE: [U-Boot] [PATCH] spl: make image arg or fdt blob address reconfigurable
> 
> Hi Tom,
> 
> > -----Original Message-----
> > From: Tom Rini [mailto:trini at konsulko.com]
> > Sent: Wednesday, April 12, 2017 6:33 AM
> > To: Vikas MANOCHA <vikas.manocha at st.com>
> > Cc: u-boot at lists.denx.de; Marek Vasut <marex at denx.de>; Stefan Agner
> > <stefan.agner at toradex.com>; Jeremy Hunt
> > <Jeremy.Hunt at DEShawResearch.com>
> > Subject: Re: [U-Boot] [PATCH] spl: make image arg or fdt blob address
> > reconfigurable
> >
> > On Tue, Apr 11, 2017 at 11:44:00PM +0000, Vikas MANOCHA wrote:
> > > Hi Tom,
> > >
> > > > -----Original Message-----
> > > > From: Tom Rini [mailto:trini at konsulko.com]
> > > > Sent: Monday, April 10, 2017 5:29 AM
> > > > To: Vikas MANOCHA <vikas.manocha at st.com>
> > > > Cc: u-boot at lists.denx.de; Marek Vasut <marex at denx.de>; Stefan
> > > > Agner <stefan.agner at toradex.com>; Jeremy Hunt
> > > > <Jeremy.Hunt at DEShawResearch.com>
> > > > Subject: Re: [U-Boot] [PATCH] spl: make image arg or fdt blob
> > > > address reconfigurable
> > > >
> > > > On Fri, Apr 07, 2017 at 03:38:13PM -0700, Vikas Manocha wrote:
> > > >
> > > > > At present fdt blob or argument address being passed to kernel
> > > > > is fixed at compile time using macro CONFIG_SYS_SPL_ARGS_ADDR.
> > > > > FDT blob from different media like nand, nor flash are copied to
> > > > > the address pointed by the macro.
> > > > > The problem is, it makes args/fdt blob compulsory to copy which
> > > > > is not required in cases like for NOR Flash. This patch removes this limitation.
> > > > >
> > > > > Signed-off-by: Vikas Manocha <vikas.manocha at st.com>
> > > > > ---
> > > > >  arch/arm/lib/spl.c        | 7 +++----
> > > > >  arch/microblaze/cpu/spl.c | 6 +++---
> > > > >  arch/powerpc/lib/spl.c    | 8 ++++----
> > > > >  common/spl/spl.c          | 6 ++++--
> > > > >  common/spl/spl_nor.c      | 8 +-------
> > > > >  include/spl.h             | 5 ++---
> > > >
> > > > I assume you've tested the spl_nor case afterwards, yes?  Did this
> > > > result in some measurable boot time decrease?  Thanks!
> > >
> > > Yes, I tested it's working on board. Not sure how to measure the impact on boot time.
> >
> > There's always good old grabserial. But if you didn't measure bootspeed, did this decrease the code size?  Or fix some other issue?
> 
> Thanks Tom for the suggestion.
> 
> The benefit of this patch is : It removes copying FDT blob from NOR flash to ram in case of booting from nor flash,  text size reduction
> is only 4 Bytes, no change in data/bss size. It might reduce the boot time but boot time impact would depend on the FDT blob
> copying time & ram vs flash read speed.
> 
> Also it provides a way to change fdt blob address at run-time which might be useful e.g. choosing between two FDT blobs or
> manipulating FDT address.

Please let me know if more info is required in order to pick this patch.

Cheers,
Vikas

> 
> Cheers,
> Vikas
> 
> > Thanks!
> >
> > --
> > Tom