[U-Boot] vxworks: fixed cpu enable using PSCI on armv8

Without armv8_setup_psci register VBAR_EL3 is not set up property which
makes SMC calls jump to invalid location.

smp_kick_all_cpus is required to make slave cpus leave gic_wait_for_interrupt.
Without this they will never pursue booting process.

This implementation is very similiar to what is done in boot_jump_linux
in arch/arm/lib/bootm.c file.

Tested on VxWorks 7 release SR0520 2017-12-08.

Signed-off-by: Vasyl Vavrychuk <vasyl.vavrychuk@globallogic.com>
---
 cmd/elf.c | 5 +++++
 1 file changed, 5 insertions(+)

Hi Vasyl,

On Wed, Mar 28, 2018 at 3:29 AM, Vasyl Vavrychuk <vvavrychuk@gmail.com> wrote:
> Without armv8_setup_psci register VBAR_EL3 is not set up property which
> makes SMC calls jump to invalid location.
>
> smp_kick_all_cpus is required to make slave cpus leave gic_wait_for_interrupt.
> Without this they will never pursue booting process.
>
> This implementation is very similiar to what is done in boot_jump_linux
> in arch/arm/lib/bootm.c file.
>
> Tested on VxWorks 7 release SR0520 2017-12-08.
>

On what board?

As I mentioned before, why do you want to use 'bootvx' to boot a
VxWorks 7 kernel? I believe VxWorks 7 ARM kernel is loaded via
'bootm'. See doc/README.vxworks.

> Signed-off-by: Vasyl Vavrychuk <vasyl.vavrychuk@globallogic.com>
> ---
>  cmd/elf.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/cmd/elf.c b/cmd/elf.c
> index 5745a389da..db690fc619 100644
> --- a/cmd/elf.c
> +++ b/cmd/elf.c
> @@ -372,6 +372,11 @@ int do_bootvx(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>         printf("## Starting vxWorks at 0x%08lx ...\n", addr);
>
>         dcache_disable();
> +#if defined(CONFIG_ARM64) && defined(CONFIG_ARMV8_PSCI)
> +       armv8_setup_psci();
> +       smp_kick_all_cpus();

What about ARMv8 32-bit? What about ARMv7? Should we call
smp_kick_all_cpus() for ARMv7 as well? Seems to me the logic of
#ifdefs here needs to be tuned.

> +#endif
> +
>  #ifdef CONFIG_X86
>         /* VxWorks on x86 uses stack to pass parameters */
>         ((asmlinkage void (*)(int))addr)(0);
> --

Regards,
Bin

Hi, Bin Meng,

Thanks for your suggestions. Please find my comments below

On Wed, Mar 28, 2018 at 7:36 AM, Bin Meng <bmeng.cn@gmail.com> wrote:
>
> >
> > Tested on VxWorks 7 release SR0520 2017-12-08.
> >
>
> On what board?

Intel Stratix 10 DevKit

> As I mentioned before, why do you want to use 'bootvx' to boot a
> VxWorks 7 kernel? I believe VxWorks 7 ARM kernel is loaded via
> 'bootm'. See doc/README.vxworks.

I have just tried what I found first, but I can add support of ARMv8
PSCI to the bootm for vxworks 7 too.

Anyway, if we add support of ARMv8 PSCI to bootm for vxworks 7, then
do you think that bootvx should not support this feature?

>
> > +#if defined(CONFIG_ARM64) && defined(CONFIG_ARMV8_PSCI)
> > +       armv8_setup_psci();
> > +       smp_kick_all_cpus();
>
> What about ARMv8 32-bit?
Do you mean ARMv8 32-bit U-Boot or ARMv8 32-bit VxWorks under ARMv8
64-bit U-Boot?

> What about ARMv7? Should we call smp_kick_all_cpus() for ARMv7 as well?
As far as I understand from U-Boot code gic_wait_for_interrupt is
called only for ARMv8. I think this is related to the difference how
cpu cores start from reset on armv7 and armv8.

On armv7 usually only core0 starts after power on and other cores are
started by the platform specific means. On armv8 usually all cores
starts after power on.

> Seems to me the logic of #ifdefs here needs to be tuned.
I have made a minimal set of changes need to implement functionality
that are required for our customer, i.e. booting 64-bit vxworks on
armv8.

I am not very willing to generalize it without a need. Maybe just no
one will require it at all.

Kind regards,
Vasyl

Hi Vasyl,

On Wed, Mar 28, 2018 at 7:27 PM, Vasyl Vavrychuk
<vasyl.vavrychuk@globallogic.com> wrote:
> Hi, Bin Meng,
>
> Thanks for your suggestions. Please find my comments below
>
> On Wed, Mar 28, 2018 at 7:36 AM, Bin Meng <bmeng.cn@gmail.com> wrote:
>>
>> >
>> > Tested on VxWorks 7 release SR0520 2017-12-08.
>> >
>>
>> On what board?
>
> Intel Stratix 10 DevKit
>

Thanks for the info.

>> As I mentioned before, why do you want to use 'bootvx' to boot a
>> VxWorks 7 kernel? I believe VxWorks 7 ARM kernel is loaded via
>> 'bootm'. See doc/README.vxworks.
>
> I have just tried what I found first, but I can add support of ARMv8
> PSCI to the bootm for vxworks 7 too.
>

Hold on..

> Anyway, if we add support of ARMv8 PSCI to bootm for vxworks 7, then
> do you think that bootvx should not support this feature?
>

Why I mentioned the 'bootm' command, is that AFAIK the only official
way of booting a VxWorks 7 ARM kernel is to use 'bootm'. Are you
saying that 'bootm' command does not work on your Intel Stratix 10
DevKit board? If that's the case, we have something to fix.

Having said that, having 'bootvx' to support booting a 64-bit VxWorks
7 ARM kernel is a nice to have.

>>
>> > +#if defined(CONFIG_ARM64) && defined(CONFIG_ARMV8_PSCI)
>> > +       armv8_setup_psci();
>> > +       smp_kick_all_cpus();
>>
>> What about ARMv8 32-bit?
> Do you mean ARMv8 32-bit U-Boot or ARMv8 32-bit VxWorks under ARMv8
> 64-bit U-Boot?
>

I meant to say ARMv8 32-bit U-Boot. I am not sure if 32-bit U-Boot can
load a 64-bit VxWorks kernel..

>> What about ARMv7? Should we call smp_kick_all_cpus() for ARMv7 as well?
> As far as I understand from U-Boot code gic_wait_for_interrupt is
> called only for ARMv8. I think this is related to the difference how
> cpu cores start from reset on armv7 and armv8.
>
> On armv7 usually only core0 starts after power on and other cores are
> started by the platform specific means. On armv8 usually all cores
> starts after power on.
>
>> Seems to me the logic of #ifdefs here needs to be tuned.
> I have made a minimal set of changes need to implement functionality
> that are required for our customer, i.e. booting 64-bit vxworks on
> armv8.
>
> I am not very willing to generalize it without a need. Maybe just no
> one will require it at all.

Understood. Thanks for the clarification. I was trying to understand
the reason of modifying this as I believe 'bootm' should work out of
the box.

Regards,
Bin

Hi Bin,

On Sun, Apr 1, 2018 at 4:51 PM, Bin Meng <bmeng.cn@gmail.com> wrote:
>
> Why I mentioned the 'bootm' command, is that AFAIK the only official
> way of booting a VxWorks 7 ARM kernel is to use 'bootm'. Are you
> saying that 'bootm' command does not work on your Intel Stratix 10
> DevKit board? If that's the case, we have something to fix.
>
> Having said that, having 'bootvx' to support booting a 64-bit VxWorks
> 7 ARM kernel is a nice to have.
Yes, there is the same issue with bootm for ARMv8. It works but only
one CPU core is enabled.

>>>
>>> > +#if defined(CONFIG_ARM64) && defined(CONFIG_ARMV8_PSCI)
>>> > +       armv8_setup_psci();
>>> > +       smp_kick_all_cpus();
>>>
>>> What about ARMv8 32-bit?
>> Do you mean ARMv8 32-bit U-Boot or ARMv8 32-bit VxWorks under ARMv8
>> 64-bit U-Boot?
>>
>
> I meant to say ARMv8 32-bit U-Boot. I am not sure if 32-bit U-Boot can
> load a 64-bit VxWorks kernel..

Is ARMv8 32-bit U-Boot supported?

>
> I was trying to understand the reason of modifying this as I believe 'bootm'
> should work out of the box.
I will submit patch for bootm command in the next email.

Kind regards,
Vasyl