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Date: Sat, 03 Jul 2010 14:04:12 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai-core] [PATCH 5/7] posix: Support reading the host
 realtime clock in realtime context
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To: Wolfgang Mauerer <wolfgang.mauerer@domain.hid>
Cc: Jan Kiszka <jan.kiszka@domain.hid>, xenomai@xenomai.org

Wolfgang Mauerer wrote:
> Wall time management is typically assisted by the NTP
> protocol in the Linux context, but this information is
> not propagated to Xenomai. This patch adds support
> for a CLOCK_HOST_REALTIME clock id that is coupled to the
> host operating system's realtime clock. The required
> information from the Kernel into Xenomai. The data exchange
> is designed to allow for lockless reading from userland.
> 
> Signed-off-by: Wolfgang Mauerer <wolfgang.mauerer@domain.hid>
> Signed-off-by: Jan Kiszka <jan.kiszka@domain.hid>
> ---
>  include/posix/time.h     |    2 +
>  ksrc/skins/posix/clock.c |   90 +++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 91 insertions(+), 1 deletions(-)
> 
> diff --git a/include/posix/time.h b/include/posix/time.h
> index 4f2d760..938feb6 100644
> --- a/include/posix/time.h
> +++ b/include/posix/time.h
> @@ -50,6 +50,8 @@
>  #define CLOCK_MONOTONIC 1
>  #endif /* CLOCK_MONOTONIC */
>  
> +#define CLOCK_HOST_REALTIME 16
> +
>  #if defined(__KERNEL__) || defined(__XENO_SIM__)
>  
>  struct sigevent;
> diff --git a/ksrc/skins/posix/clock.c b/ksrc/skins/posix/clock.c
> index 553e123..f5a789b 100644
> --- a/ksrc/skins/posix/clock.c
> +++ b/ksrc/skins/posix/clock.c
> @@ -50,6 +50,13 @@
>   *@{*/
>  
>  #include <posix/thread.h>
> +#include <linux/ipipe_tickdev.h>
> +#include <linux/math64.h>

Do we really need this? Because we probably do not have it in 2.4
kernels. Besides, we do not include linux/ headers in Xenomai code.

> +static int do_clock_host_realtime(struct timespec *tp)
> +{
> +#ifdef CONFIG_XENO_OPT_HOSTRT
> (...)
> +	return 0;
> +#else /* CONFIG_XENO_OPT_HOSTRT */
> +	return -1;

return -EINVAL;

> +	case CLOCK_HOST_REALTIME:
> +		if (do_clock_host_realtime(tp) != 0) {
		rc = do_clock_host_realtime(tp);
		if (rc < 0) {
			thread_set_errno(-rc);
			return -1;
		}


-- 
					    Gilles.