Re: [PATCH] arm64: kernel: Copy register_persistent_clock() to arm64 source subtree

[Anatol Pomozov]

+Stephen

This patch is for tegra20_timer that uses register_persistent_clock().
I did not find any way to share the same arch code for arm/arm64.

Actually this register_persistent_clock() does not look arm specific
at all. Would it be better to move it somewhere outside of arch/?

On Thu, Nov 6, 2014 at 4:21 PM, Anatol Pomozov <anatol.pomozov@xxxxxxxxx> wrote:
> This allows to port code that needs register_persistent_clock() to arm64
>
> Signed-off-by: Anatol Pomozov <anatol.pomozov@xxxxxxxxx>
> ---
>  arch/arm64/include/asm/time.h | 17 +++++++++++++++++
>  arch/arm64/kernel/time.c      | 37 +++++++++++++++++++++++++++++++++++++
>  2 files changed, 54 insertions(+)
>  create mode 100644 arch/arm64/include/asm/time.h
>
> diff --git a/arch/arm64/include/asm/time.h b/arch/arm64/include/asm/time.h
> new file mode 100644
> index 0000000..28015b8
> --- /dev/null
> +++ b/arch/arm64/include/asm/time.h
> @@ -0,0 +1,17 @@
> +/*
> + * Copyright (C) 2004 MontaVista Software, Inc.
> + * Copyright (C) 2014 The Chromium OS Authors.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#ifndef __ASM_TIME_H
> +#define __ASM_TIME_H
> +
> +struct timespec;
> +typedef void (*clock_access_fn)(struct timespec *);
> +extern int register_persistent_clock(clock_access_fn read_boot,
> +               clock_access_fn read_persistent);
> +
> +#endif
> diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
> index 1a7125c..71a907e 100644
> --- a/arch/arm64/kernel/time.c
> +++ b/arch/arm64/kernel/time.c
> @@ -40,6 +40,7 @@
>
>  #include <asm/thread_info.h>
>  #include <asm/stacktrace.h>
> +#include <asm/time.h>
>
>  #ifdef CONFIG_SMP
>  unsigned long profile_pc(struct pt_regs *regs)
> @@ -79,3 +80,39 @@ void __init time_init(void)
>         /* Calibrate the delay loop directly */
>         lpj_fine = arch_timer_rate / HZ;
>  }
> +
> +static void dummy_clock_access(struct timespec *ts)
> +{
> +       ts->tv_sec = 0;
> +       ts->tv_nsec = 0;
> +}
> +
> +static clock_access_fn __read_persistent_clock = dummy_clock_access;
> +static clock_access_fn __read_boot_clock = dummy_clock_access;
> +
> +void read_persistent_clock(struct timespec *ts)
> +{
> +       __read_persistent_clock(ts);
> +}
> +
> +void read_boot_clock(struct timespec *ts)
> +{
> +       __read_boot_clock(ts);
> +}
> +
> +int __init register_persistent_clock(clock_access_fn read_boot,
> +                                    clock_access_fn read_persistent)
> +{
> +       /* Only allow the clockaccess functions to be registered once */
> +       if (__read_persistent_clock == dummy_clock_access &&
> +           __read_boot_clock == dummy_clock_access) {
> +               if (read_boot)
> +                       __read_boot_clock = read_boot;
> +               if (read_persistent)
> +                       __read_persistent_clock = read_persistent;
> +
> +               return 0;
> +       }
> +
> +       return -EINVAL;
> +}
> --
> 2.1.0.rc2.206.gedb03e5
>
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