From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC PATCH] ARM: Make a compile trustzone conditionally
Date: Wed, 20 Jun 2012 11:14:16 +0000 [thread overview]
Message-ID: <201206201114.17033.arnd@arndb.de> (raw)
In-Reply-To: <CAH9JG2UwwvZTK+RptKQ+fmfAMHeqyXG=eo9bJN+JogGBDTgqNQ@mail.gmail.com>
On Tuesday 19 June 2012, Kyungmin Park wrote:
> > Would it help to have a trustzone_ops structure with pointers to
> > functions if needed, similar to but separate from smp_ops?
> Here's real usages. I'm not sure it's possible since smc call is
> vendor specific.
I would hope that there is at last some overlap, as well as only a
limited number of things that you might want to do with smc.
> static int exynos4_cpu_suspend(unsigned long arg)
> {
> outer_flush_all();
>
> /* issue the standby signal into the pm unit. */
> if (trustzone_enabled())
> exynos_smc(SMC_CMD_SLEEP, 0, 0, 0);
> else
> cpu_do_idle();
>
> /* we should never get past here */
> panic("sleep resumed to originator?");
> }
This looks straightforward to implement as an indirect call just for
cpu_do_idle. We already have an indirection layer for cpu-specific
do_idle functions. It would be ideal to have only one level of
indirection, but the extra level would work as well.
> static int exynos4_cpu_suspend(unsigned long arg)
> {
> outer_flush_all();
>
> /* issue the standby signal into the pm unit. */
> cpu_do_idle();
>
> /* we should never get past here */
> panic("sleep resumed to originator?");
> }
>
> static int exynos4_cpu_smc_suspend(unsigned long arg)
> {
> outer_flush_all();
>
> exynos_smc(SMC_CMD_SLEEP, 0, 0, 0);
>
> /* we should never get past here */
> panic("sleep resumed to originator?");
> }
>
> but still we should check it's trustzone is enabled or not to assign
> proper function into pm_cpu_suspend
>
> I think it's different from smp_ops.
This is a different method from what I had in mind, but it would
work too. It's not platform independent though.
What I was thinking of is something along the lines of
static void nosmc_cpu_do_idle(void)
{
cpu_do_idle();
}
struct smc_ops {
void (*do_idle)(void);
...
};
struct smc_ops default_smc_ops = {
.do_idle = nosmc_cpu_do_idle,
...
};
So the exynos4_cpu_suspend() function would just do an indirect call to
smc->do_idle(), which is either nosmc_cpu_do_idle or a function specific
to the smc firmware.
Arnd
next prev parent reply other threads:[~2012-06-20 11:14 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-11 5:15 [RFC PATCH] ARM: Make a compile trustzone conditionally Kyungmin Park
2012-06-18 0:58 ` Kyungmin Park
2012-06-18 1:10 ` Olof Johansson
2012-06-18 4:37 ` Kyungmin Park
2012-06-18 14:10 ` Arnd Bergmann
2012-06-19 6:50 ` Kyungmin Park
2012-06-20 11:14 ` Arnd Bergmann [this message]
2012-06-20 14:41 ` Dave Martin
2012-06-20 16:01 ` Arnd Bergmann
2012-06-20 1:22 ` Stephen Boyd
2012-06-20 9:43 ` Will Deacon
2012-06-20 10:51 ` Bindings for SMC/HVC firmware interfaces on ARM (Re: [RFC PATCH] ARM: Make a compile trustzone conditionally) Dave Martin
2012-06-20 15:14 ` Rob Herring
2012-06-20 15:34 ` Dave Martin
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