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

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

[Renaud Barbier]

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
 
 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);
-- 
2.27.0

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

[Ahmad Fatoum]

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);

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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

[Renaud Barbier]

> > 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?
> 
> 
Is there a list of boards I can build barebox against to cover this case?

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

[Renaud Barbier]

> 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

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

[Sascha Hauer]

On Fri, Mar 03, 2023 at 09:23:13AM +0000, 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

I don't see what the ifeq is needed for. I think you can drop it.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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

[Ahmad Fatoum]

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



-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |