From: Tom Rini <tr...@konsulko.com> Sent: Tuesday, April 8, 2025 10:58 PM > To: Christoph Niedermaier <cniederma...@dh-electronics.com> > Cc: u-boot@lists.denx.de; Simon Glass <s...@chromium.org>; Michael Walle > <mwa...@kernel.org>; Quentin Schulz <quentin.sch...@cherry.de>; Marek Vasut > <ma...@denx.de>; Benedikt Spranger <b.spran...@linutronix.de>; Jerome > Forissier > <jerome.foriss...@linaro.org>; John Ogness <john.ogn...@linutronix.de>; Ilias > Apalodimas > <ilias.apalodi...@linaro.org> > Subject: Re: [PATCH] tiny-printf: Handle formatting of %p with an extra > Kconfig > > On Mon, Apr 07, 2025 at 10:56:14AM +0200, Christoph Niedermaier wrote: > >> The formatting with %pa / %pap behaves like %x, which results in an >> incorrect value being output. To improve this, a new fine-tuning >> Kconfig XPL_USE_TINY_PRINTF_POINTER_SUPPORT for pointer formatting >> has been added. If it is enabled, the output of %pa / %pap should >> be correct, and if it is disabled, the pointer formatting is >> completely unsupported. In addition to indicate unsupported formatting, >> '?' will be output. This allows enabling pointer formatting only >> when needed. For SPL_NET and NET_LWIP it is selected by default. >> Then it also supports the formatting with %pm, %pM and %pI4. >> >> Signed-off-by: Christoph Niedermaier <cniederma...@dh-electronics.com> >> --- >> Cc: Tom Rini <tr...@konsulko.com> >> Cc: Simon Glass <s...@chromium.org> >> Cc: Michael Walle <mwa...@kernel.org> >> Cc: Quentin Schulz <quentin.sch...@cherry.de> >> Cc: Marek Vasut <ma...@denx.de> >> Cc: Benedikt Spranger <b.spran...@linutronix.de> >> Cc: Jerome Forissier <jerome.foriss...@linaro.org> >> Cc: John Ogness <john.ogn...@linutronix.de> >> Cc: Ilias Apalodimas <ilias.apalodi...@linaro.org> >> --- >> Kconfig | 1 + >> common/spl/Kconfig | 1 + >> lib/Kconfig | 8 ++++++++ >> lib/tiny-printf.c | 45 +++++++++++++++++++-------------------------- >> 4 files changed, 29 insertions(+), 26 deletions(-) >> >> diff --git a/Kconfig b/Kconfig >> index 6379a454166..4d13717294c 100644 >> --- a/Kconfig >> +++ b/Kconfig >> @@ -757,6 +757,7 @@ config NET >> >> config NET_LWIP >> bool "Use lwIP for networking stack" >> + select XPL_USE_TINY_PRINTF_POINTER_SUPPORT if SPL_USE_TINY_PRINTF || >> TPL_USE_TINY_PRINTF || VPL_USE_TINY_PRINTF >> imply NETDEVICES >> help >> Include networking support based on the lwIP (lightweight IP) >> diff --git a/common/spl/Kconfig b/common/spl/Kconfig >> index 94e118f8465..72736dbecf5 100644 >> --- a/common/spl/Kconfig >> +++ b/common/spl/Kconfig >> @@ -1096,6 +1096,7 @@ config SPL_DM_SPI_FLASH >> config SPL_NET >> bool "Support networking" >> depends on !NET_LWIP >> + select XPL_USE_TINY_PRINTF_POINTER_SUPPORT if SPL_USE_TINY_PRINTF || >> TPL_USE_TINY_PRINTF || VPL_USE_TINY_PRINTF >> help >> Enable support for network devices (such as Ethernet) in SPL. >> This permits SPL to load U-Boot over a network link rather than >> diff --git a/lib/Kconfig b/lib/Kconfig >> index 1a683dea670..62e28d4a1f3 100644 >> --- a/lib/Kconfig >> +++ b/lib/Kconfig >> @@ -253,6 +253,14 @@ config VPL_USE_TINY_PRINTF >> >> The supported format specifiers are %c, %s, %u/%d and %x. >> >> +config XPL_USE_TINY_PRINTF_POINTER_SUPPORT >> + bool "Extend tiny printf with the pointer formatting %p" >> + depends on SPL_USE_TINY_PRINTF || TPL_USE_TINY_PRINTF || >> VPL_USE_TINY_PRINTF >> + help >> + This option enables the formatting of pointers %p. It supports >> + %p and %pa / %pap. If this option is selected by SPL_NET or NET_LWIP >> + it also supports the formatting with %pm, %pM and %pI4. > > This isn't quite what I'd like to see. I don't want to start using the > literal XPL namespace as that will lead to confusion down the line.
OK, in V2 I will only support SPL. > Since we only have SPL_NET, I think we should name this symbol > SPL_USE_TINY_PRINTF_POINTER_SUPPORT, not ask about it (so bool without > "prompt text" following), and select from SPL_NET if > SPL_USE_TINY_PRINTF. Now you will get the output '?' when using formatting with %p or %pa. If someone wants to use the pointer support e.g. %pa in pinctrl-single.c and is restricted to use tiny printf, then it would be good to have the option to enable it manually and not be forced to enable SPL_NET or NET_LWIP to have the pointer support enabled. In this case, it makes sense to allow switching it on in menuconfig. Regards Christoph
