From: Philippe Gerum <rpm@xenomai.org>
To: Bosko Radivojevic <bosko.radivojevic@domain.hid>
Cc: xenomai-help <xenomai@xenomai.org>
Subject: Re: [Xenomai-help] Kernel functions
Date: Mon, 17 Mar 2008 15:27:26 +0100 [thread overview]
Message-ID: <47DE7FCE.4050604@domain.hid> (raw)
In-Reply-To: <d6c8ef150803170707l7161255an6fa1bf1f3627395f@domain.hid>
Bosko Radivojevic wrote:
> Hi Philippe,
>
> is the usage of __raw_writel(), dma_map_single() and simillar
> functions "allowed" in native skin?
>
I'm assuming you mean "real-time mode". __raw_write routines should always be
ok, but dma_map_single() has an arch-dependent implementation. I would be ok to
call it on Blackfin from a real-time (i.e. non plain Linux) context, but this
would break on ARM.
The rule of thumb is that a Linux service may be called from a co-kernel context
only if it does not depend on:
- regular interrupt control ops (local_irq_*)
- regular spin locks (spin_*)
Which leaves very few candidates, actually.
E.g. dma_map_single() on ARM may invoke kmalloc(), which would break all the
assumptions above.
> Kind regards,
> Bosko
>
--
Philippe.
next prev parent reply other threads:[~2008-03-17 14:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-17 14:07 [Xenomai-help] Kernel functions Bosko Radivojevic
2008-03-17 14:27 ` Philippe Gerum [this message]
2008-03-17 15:19 ` Bosko Radivojevic
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