[PATCH] startup: introduce global.endianness variable

[Antony Pavlov]

On Mon, 3 May 2021 13:16:43 +0200
Sascha Hauer <s.hauer at pengutronix.de> wrote:

Hi Sascha!

> On Mon, Apr 26, 2021 at 05:30:25PM +0300, Antony Pavlov wrote:
> > The global.endianness variable makes it possible
> > to determine current endian mode from command
> > line or from script on bi-endian capable system.
> > 
> > Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
> > ---
> >  common/globalvar.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> > 
> > diff --git a/common/globalvar.c b/common/globalvar.c
> > index a55b38b00f..75ce6331b7 100644
> > --- a/common/globalvar.c
> > +++ b/common/globalvar.c
> > @@ -641,6 +641,8 @@ int globalvar_add_simple_ip(const char *name, IPaddr_t *ip)
> >  
> >  static int globalvar_init(void)
> >  {
> > +	const char *endianness;
> > +
> >  	register_device(&global_device);
> >  
> >  	if (IS_ENABLED(CONFIG_NVVAR))
> > @@ -651,6 +653,13 @@ static int globalvar_init(void)
> >  	if (strlen(buildsystem_version_string) > 0)
> >  		globalvar_add_simple("buildsystem.version", buildsystem_version_string);
> >  
> > +	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
> > +		endianness = "big";
> > +	else
> > +		endianness = "little";
> 
> PowerPC is for sure big endian, but doesn't set CONFIG_CPU_BIG_ENDIAN,
> so will be erroneously be identified as little endian with this patch.
> Either you fix that or depend on something like #if __BYTE_ORDER ==
> __LITTLE_ENDIAN

Barebox don't use "__BYTE_ORDER == __*_ENDIAN" solution. 

Please see include/envfs.h:

#ifdef __BAREBOX__
#  ifdef __LITTLE_ENDIAN
#    define ENVFS_ORDER_LITTLE
#  elif defined __BIG_ENDIAN
#    define ENVFS_ORDER_BIG
#  else
#    error "could not determine byte order"
#  endif
#else
#  if __BYTE_ORDER == __LITTLE_ENDIAN
#    define ENVFS_ORDER_LITTLE
#  elif __BYTE_ORDER == __BIG_ENDIAN
#    define ENVFS_ORDER_BIG
#  else
#    error "could not determine byte order"
#  endif
#endif

-- 
Best regards,
  Antony Pavlov