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

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

On 03.03.23 10:23, Renaud Barbier wrote:
>> 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?
>>
>>
> 
> Would something like below makes sense in arch/arm/lib32/Makefile:
> 
> pbl-$(CONFIG_CLOCKSOURCE_ARM_ARCHITECTED_TIMER) += arm_architected_timer.o
> ifeq ($(CONFIG_CPU_32v7),y)
> CFLAGS_arm_architected_timer.o := -march=armv7-a
> endif
If you try to compile this for CPU_32v6, you will get an assembler error.
That's why you need to explicitly set -march=armv7-a for everything that
would not work otherwise. Of course if you are on v6 and try to execute
a function containing the unallowed instructions, you get an exception,
but that shouldn't happen as you wouldn't register a clocksource on such
a platform.

In your case, you could just change it to pbl-$(CONFIG_CPU_32v7) += arm_architected_timer.o



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