[PATCH 1/2] bloblist: Introduce BLOBLIST_PRIOR_STAGE options

[Tom Rini]

On Thu, Dec 12, 2024 at 06:34:44PM +0200, Ilias Apalodimas wrote:
> Hi Tom,
> 
> On Thu, Dec 12, 2024 at 09:11:41AM -0600, Tom Rini wrote:
> > Introduce an option to control if we expect that a prior stage has
> > created a bloblist already and thus it is safe to scan the address. We
> > need to have this be configurable because we do not (and cannot) know if
> > the address at CONFIG_BLOBLIST_ADDR is in regular DRAM or some special
> > on-chip memory and so it may or may not be safe to read from this
> > address this early.
> 
> Yes this patch makes instead of making the OF_SEPARATE implicitly take
> priority
> 
> >
> > Signed-off-by: Tom Rini <trini at konsulko.com>
> > ---
> > Cc: Simon Glass <sjg at chromium.org>
> > ---
> >  common/Kconfig | 32 ++++++++++++++++++++++++++++++++
> >  lib/fdtdec.c   | 11 +++--------
> >  2 files changed, 35 insertions(+), 8 deletions(-)
> >
> > diff --git a/common/Kconfig b/common/Kconfig
> > index e8d89bf6eb9d..e8febad0f212 100644
> > --- a/common/Kconfig
> > +++ b/common/Kconfig
> > @@ -1077,6 +1077,14 @@ config BLOBLIST_SIZE
> >  	  is set up in the first part of U-Boot to run (TPL, SPL or U-Boot
> >  	  proper), and this sane bloblist is used for subsequent phases.
> >
> > +config BLOBLIST_PRIOR_STAGE
> > +	bool "Bloblist was created in a stage prior to U-Boot"
> > +	default y
> > +	depends on BLOBLIST_FIXED
> > +	help
> > +	  Select this if the bloblist at CONFIG_BLOBLIST_ADDR was created
> > +	  before U-Boot is started.
> > +
> >  config BLOBLIST_SIZE_RELOC
> >  	hex "Size of bloblist after relocation"
> >  	default BLOBLIST_SIZE if BLOBLIST_FIXED || BLOBLIST_ALLOC
> > @@ -1117,6 +1125,14 @@ config SPL_BLOBLIST_ALLOC
> >
> >  endchoice
> >
> > +config SPL_BLOBLIST_PRIOR_STAGE
> > +	bool "Bloblist was created in a stage prior to SPL"
> > +	default y
> > +	depends on SPL_BLOBLIST_FIXED
> > +	help
> > +	  Select this if the bloblist at CONFIG_BLOBLIST_ADDR was created before
> > +	  U-Boot SPL is started.
> > +
> >  endif # SPL_BLOBLIST
> >
> >  if TPL_BLOBLIST
> > @@ -1146,6 +1162,14 @@ config TPL_BLOBLIST_ALLOC
> >
> >  endchoice
> >
> > +config TPL_BLOBLIST_PRIOR_STAGE
> > +	bool "Bloblist was created in a stage prior to TPL"
> > +	default y
> > +	depends on TPL_BLOBLIST_FIXED
> > +	help
> > +	  Select this if the bloblist at CONFIG_BLOBLIST_ADDR was created before
> > +	  U-Boot TPL is started.
> > +
> >  endif # TPL_BLOBLIST
> >
> >  if VPL_BLOBLIST
> > @@ -1175,6 +1199,14 @@ config VPL_BLOBLIST_ALLOC
> >
> >  endchoice
> >
> > +config VPL_BLOBLIST_PRIOR_STAGE
> > +	bool "Bloblist was created in a stage prior to VPL"
> > +	default y
> > +	depends on VPL_BLOBLIST_FIXED
> > +	help
> > +	  Select this if the bloblist at CONFIG_BLOBLIST_ADDR was created before
> > +	  U-Boot VPL is started.
> > +
> >  endif # VPL_BLOBLIST
> >
> >  endmenu
> > diff --git a/lib/fdtdec.c b/lib/fdtdec.c
> > index b06559880296..29bddab4150c 100644
> > --- a/lib/fdtdec.c
> > +++ b/lib/fdtdec.c
> > @@ -1669,15 +1669,10 @@ int fdtdec_setup(void)
> >  	int ret = -ENOENT;
> >
> >  	/*
> > -	 * If allowing a bloblist, check that first. There was discussion about
> > -	 * adding an OF_BLOBLIST Kconfig, but this was rejected.
> > -	 *
> > -	 * The necessary test is whether the previous phase passed a bloblist,
> > -	 * not whether this phase creates one.
> > +	 * Only scan for a bloblist and then if that bloblist contains a device
> > +	 * tree if we have been configured to expect one.
> >  	 */
> > -	if (CONFIG_IS_ENABLED(BLOBLIST) &&
> > -	    (xpl_prev_phase() != PHASE_TPL ||
> > -	     !IS_ENABLED(CONFIG_TPL_BLOBLIST))) {
> > +	if (CONFIG_IS_ENABLED(BLOBLIST_PRIOR_STAGE)) {
> 
> Without wider context I am not sure but if that check can fold in
> bloblist_maybe_init() and return -X if the config isn't enabled, it's going
> to be easier to read

Hmm. We'd have:
	if (CONFIG_IS_ENABLED(BLOBLIST_PRIOR_STAGE) && 
	    !(ret = bloblist_maybe_init()) {
		/* We have a bloblist, see if it has FDT */
		gd->fdt_blob = bloblist_find(BLOBLISTT_CONTROL_FDT, 0);
		....

And I don't think that reads better.

-- 
Tom
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