Re: [PATCH 3/3] pbl: introduce HAS_PBL_CLOCKSOURCE marker

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello Stefan,

On 21.01.25 17:49, Stefan Kerkmann wrote:
> This finally enables the usage of the polled timeout functions in the
> barebox pbl with real timeouts for supported architectures. Currently
> only ARMv7 and ARMv8 are enabled.
> 
> Signed-off-by: Stefan Kerkmann <s.kerkmann@pengutronix.de>
> ---
>  arch/arm/cpu/Kconfig    | 2 ++
>  arch/arm/lib32/Makefile | 2 +-
>  include/linux/iopoll.h  | 8 ++++----
>  pbl/Kconfig             | 3 +++
>  4 files changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/cpu/Kconfig b/arch/arm/cpu/Kconfig
> index 84fe770b6da892723528eeea89ae2b0eda122d07..3569f3d3483a6289d7a6eca3d1715e06144df8d4 100644
> --- a/arch/arm/cpu/Kconfig
> +++ b/arch/arm/cpu/Kconfig
> @@ -84,6 +84,7 @@ config CPU_V6
>  config CPU_V7
>  	bool
>  	select CPU_32v7
> +	select HAS_PBL_CLOCKSOURCE
>  
>  # ARMv8
>  config CPU_V8
> @@ -125,6 +126,7 @@ config CPU_32v7
>  config CPU_64v8
>  	bool
>  	select CPU_64
> +	select HAS_PBL_CLOCKSOURCE
>  
>  comment "processor features"
>  
> diff --git a/arch/arm/lib32/Makefile b/arch/arm/lib32/Makefile
> index a139a80fb84973e01e24b063eb6b1d774a60a056..4509d483b27ec7da038b17729f552d6f09fd39ec 100644
> --- a/arch/arm/lib32/Makefile
> +++ b/arch/arm/lib32/Makefile
> @@ -31,7 +31,7 @@ extra-y += barebox.lds
>  pbl-y	+= lib1funcs.o
>  pbl-y	+= ashldi3.o
>  pbl-y	+= div0.o
> -pbl-$(CONFIG_CPU_32v7)	+= arm_architected_timer.o
> +pbl-$(CONFIG_HAS_PBL_CLOCKSOURCE)	+= arm_architected_timer.o
>  CFLAGS_arm_architected_timer.o := -march=armv7-a
>  
>  obj-pbl-y	+= setjmp.o
> diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
> index 9350a3d05007fbf760e2dea2a981cb86641343fd..df7fdbfa4ae0aec825cc02afa8f14d1ea1f1e535 100644
> --- a/include/linux/iopoll.h
> +++ b/include/linux/iopoll.h
> @@ -26,19 +26,19 @@
>   * When available, you'll probably want to use one of the specialized
>   * macros defined below rather than this macro directly.
>   *
> - * We do not have timing functions in the PBL, so ignore the timeout value and
> - * loop infinitely here.
> + * In the PBL the timeout is ignored if timing functions are not implemented.
> + * This potentially means looping infinitely!
>   */
>  #define read_poll_timeout(op, val, cond, timeout_us, args...)	\
>  ({ \
>  	uint64_t start = 0; \
> -	if (IN_PROPER && (timeout_us) != 0) \
> +	if ((IN_PROPER || IS_ENABLED(CONFIG_HAS_PBL_CLOCKSOURCE)) && (timeout_us) != 0) \

This is getting too complicated. I'd prefer you factor this out into a separate
maco and have #ifdefs there. See my series for how this could look like:

https://lore.barebox.org/barebox/20250108110420.1850995-1-a.fatoum@pengutronix.de/

>  		start = get_time_ns(); \
>  	for (;;) { \
>  		(val) = op(args); \
>  		if (cond) \
>  			break; \
> -		if (IN_PROPER && (timeout_us) != 0 && \
> +		if ((IN_PROPER || IS_ENABLED(CONFIG_HAS_PBL_CLOCKSOURCE)) && (timeout_us) != 0 && \
>  		    is_timeout(start, ((timeout_us) * USECOND))) { \
>  			(val) = op(args); \
>  			break; \
> diff --git a/pbl/Kconfig b/pbl/Kconfig
> index 98d71791454b1a31f315ca3fdffa675e6d3dcb50..c2697a2bd00d807a78ac6bc9f0bcf7b28d150c59 100644
> --- a/pbl/Kconfig
> +++ b/pbl/Kconfig
> @@ -26,6 +26,9 @@ config PBL_SINGLE_IMAGE
>  	depends on !HAVE_PBL_MULTI_IMAGES
>  	default y
>  
> +config HAS_PBL_CLOCKSOURCE
> +	bool
> +
>  if PBL_IMAGE
>  
>  config USE_COMPRESSED_DTB
> 


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