From: Julien Grall <julien.grall@arm.com>
To: Oleksandr <olekstysh@gmail.com>,
linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: horms@verge.net.au, magnus.damm@gmail.com, linux@armlinux.org.uk,
biju.das@bp.renesas.com,
Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Subject: Re: [PATCH V2] ARM: mach-shmobile: Don't init CNTVOFF if PSCI is available
Date: Fri, 10 May 2019 13:53:26 +0100 [thread overview]
Message-ID: <e496aece-b092-7845-9295-25b764721724@arm.com> (raw)
In-Reply-To: <6495fca7-bdfa-9020-4eff-b2d04c19827a@gmail.com>
On 10/05/2019 13:27, Oleksandr wrote:
>
> On 06.05.19 18:37, Julien Grall wrote:
>> Hi Oleksandr,
>
> Hi Julien
>
>
>>> ---
>>> arch/arm/mach-shmobile/setup-rcar-gen2.c | 13 ++++++++++++-
>>> 1 file changed, 12 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/arm/mach-shmobile/setup-rcar-gen2.c
>>> b/arch/arm/mach-shmobile/setup-rcar-gen2.c
>>> index eea60b2..bc8537b 100644
>>> --- a/arch/arm/mach-shmobile/setup-rcar-gen2.c
>>> +++ b/arch/arm/mach-shmobile/setup-rcar-gen2.c
>>> @@ -17,7 +17,9 @@
>>> #include <linux/of.h>
>>> #include <linux/of_fdt.h>
>>> #include <linux/of_platform.h>
>>> +#include <xen/xen.h>
>>> #include <asm/mach/arch.h>
>>> +#include <asm/psci.h>
>>> #include <asm/secure_cntvoff.h>
>>> #include "common.h"
>>> #include "rcar-gen2.h"
>>> @@ -63,7 +65,16 @@ void __init rcar_gen2_timer_init(void)
>>> void __iomem *base;
>>> u32 freq;
>>> - secure_cntvoff_init();
>>> + /*
>>> + * If PSCI is available then most likely we are running on PSCI-enabled
>>> + * U-Boot which, we assume, has already taken care of resetting CNTVOFF
>>> + * before switching to non-secure mode and we don't need to.
>>> + * Another check is to be sure that we are not running on top of Xen
>>> + * hypervisor, as CNTVOFF is controlled by hypervisor itself and
>>> + * shouldn't be touched by Dom0 in such case.
>>
>> If you are running on top of Xen, then PSCI will be available. So is there any
>> real value to check the presence of Xen as well?
>
> I think, no. If the PSCI is a must to run Xen, then it is certainly an excessive
> check. I will drop it in V3.
Xen does not offer another interface for SMP bring-up.
Cheers,
--
Julien Grall
prev parent reply other threads:[~2019-05-10 12:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-03 11:17 [PATCH V2] ARM: mach-shmobile: Don't init CNTVOFF if PSCI is available Oleksandr Tyshchenko
2019-05-03 11:38 ` Geert Uytterhoeven
2019-05-03 12:28 ` Oleksandr
2019-05-06 15:37 ` Julien Grall
2019-05-10 12:27 ` Oleksandr
2019-05-10 12:53 ` Julien Grall [this message]
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