Re: Subject: [PATCH 1/3] ARM:lib32: add architected timer

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

Hello Renaud,

On 01.03.23 17:59, Renaud Barbier wrote:
> Subject: [PATCH 1/3] ARM:lib32: add architected timer
> 
> In preparation for the introduction of the LS1021A support,
> add a specific timer support based on the LS1046A support so
> that delays can be used in the PBL.
> 
> Signed-off-by: Renaud Barbier <renaud.barbier@ametek.com>
> ---
>  arch/arm/lib32/Makefile |  1 +
>  arch/arm/lib32/pbl.c    | 17 +++++++++++++++++
>  include/clock.h         |  2 ++
>  3 files changed, 20 insertions(+)
>  create mode 100644 arch/arm/lib32/pbl.c
> 
> diff --git a/arch/arm/lib32/Makefile b/arch/arm/lib32/Makefile
> index 82507fffc0..1be8d70c45 100644
> --- a/arch/arm/lib32/Makefile
> +++ b/arch/arm/lib32/Makefile
> @@ -31,6 +31,7 @@ extra-y += barebox.lds
>  pbl-y	+= lib1funcs.o
>  pbl-y	+= ashldi3.o
>  pbl-y	+= div0.o
> +pbl-y	+= pbl.o

I think we need a CFLAGS_pbl.o := -march=armv7-a here, otherwise
this would break builds of non-ARMv7 platforms.

See arm_architected_timer.o in drivers/clocksource. Also, perhaps
you should rename the file to arm_architected_timer.c as well?


>  obj-pbl-y	+= setjmp.o
>  
> diff --git a/arch/arm/lib32/pbl.c b/arch/arm/lib32/pbl.c
> new file mode 100644
> index 0000000000..83b49656cb
> --- /dev/null
> +++ b/arch/arm/lib32/pbl.c
> @@ -0,0 +1,17 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <asm/system.h>
> +#include <clock.h>
> +#include <common.h>
> +
> +/* Unlike the ARMv8, the timer is not generic to ARM32 */
> +void arm_architected_timer_udelay(unsigned long us)
> +{
> +	unsigned long long ticks, cntfrq = get_cntfrq();
> +	unsigned long long start = get_cntpct();
> +
> +	ticks = us * cntfrq + 999999;
> +	do_div(ticks, 1000000);
> +
> +	while ((long)(start + ticks - get_cntpct()) > 0);
> +}
> diff --git a/include/clock.h b/include/clock.h
> index e6197e7eb0..8e07c35d37 100644
> --- a/include/clock.h
> +++ b/include/clock.h
> @@ -35,6 +35,8 @@ uint32_t clocksource_hz2mult(uint32_t hz, uint32_t shift_constant);
>  int is_timeout(uint64_t start_ns, uint64_t time_offset_ns);
>  int is_timeout_non_interruptible(uint64_t start_ns, uint64_t time_offset_ns);
>  
> +void arm_architected_timer_udelay(unsigned long us);
> +
>  void ndelay(unsigned long nsecs);
>  void udelay(unsigned long usecs);
>  void mdelay(unsigned long msecs);

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