[PATCH] tiny-printf: Add support for upper case hex values
Michael Walle
mwalle at kernel.org
Mon Apr 7 07:27:50 CEST 2025
Hi,
> > > > I wouldn't mind printing the pointer for %p[mMI], but %pa prints the
> > > > *content* of the pointer which is really confusing. I.e. in
> > > > pinctrl-single.c the reg value pairs are printed like
> > > >
> > > > dev_dbg(dev, "reg/val %pa/0x%08x\n", ®, val);
> > > >
> > > > with reg being a pointer to a physical address. So with tiny_printf
> > > > the address of reg (which is a pointer to the stack) is printed in
> > > > this case.
> > > >
> > > > I don't think we can print %p without putting more logic into the
> > > > decoding. I think the culprit here is the fallthrough to %x, which
> > > > then leads to the confusing behavior shown above. IMHO if we want to
> > > > avoid that, we'd have to make %p entirely unsupported.
> > > >
> > > > diff --git a/lib/tiny-printf.c b/lib/tiny-printf.c
> > > > index faf55d7f327..8147ffa2c1b 100644
> > > > --- a/lib/tiny-printf.c
> > > > +++ b/lib/tiny-printf.c
> > > > @@ -269,21 +269,18 @@ static int _vprintf(struct printf_info *info, const char *fmt,
> > > > va_list va)
> > > > div_out(info, &num, div);
> > > > }
> > > > break;
> > > > +#if CONFIG_IS_ENABLED(NET) || CONFIG_IS_ENABLED(NET_LWIP) || _DEBUG
> > >
> > > What if we fine-tune tinyprinf via config here?
> > > For example SPL_USE_TINY_PRINTF_POINTER_SUPPORT and
> > > select it by NET or NET_LWIP. If someone needs it,
> > > the pointer output can be enabled, otherwise '?' for
> > > unsupported is output.
> >
> > Yeah I had a similar idea, but I'm not sure if yet another config
> > symbol is worth it. That's up to the maintainer to decide :)
> >
> > In any case, we have a different behavior to what is printed
> > right now, as we drop the fallthrough to %x. Tom? Simon?
>
> A Kconfig symbol that NET||NET_LWIP select seems fine, and fall through
> to printing "?".
Great! Christoph, will you prepare a patch or should I?
-michael
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 297 bytes
Desc: not available
URL: <https://lists.denx.de/pipermail/u-boot/attachments/20250407/66494d70/attachment.sig>
More information about the U-Boot
mailing list