Re: [JUST RFC] ARM: DIGIC: add csrc-dummy

[Alexander Aring <alex.aring@gmail.com>]

Hi Antony,

On Sun, Dec 15, 2013 at 07:02:05PM +0400, Antony Pavlov wrote:
> The clocksource csrc-timer driver that uses DIGIC
> hardware TIMER2 perfectrly works on Canon A1100,
> but does not works on Canon EOS 600D.
> IMHO we need additional timer initialisation.
> 
> This patch introduces a quick-and-dirty termporary
> solution for this situation: a clocksource driver that
> does not use any hardware at all.
> 
> Also this driver is very handy for running barebox
> on Magic Lantern EOS qemu-based emulator as
> the emulator does not realize timer counter register at all!
> 
> Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
> ---
>  arch/arm/mach-digic/Kconfig      |  3 +++
>  arch/arm/mach-digic/Makefile     |  1 +
>  arch/arm/mach-digic/csrc-dummy.c | 49 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 53 insertions(+)
>  create mode 100644 arch/arm/mach-digic/csrc-dummy.c
> 
> diff --git a/arch/arm/mach-digic/Kconfig b/arch/arm/mach-digic/Kconfig
> index 557cad4..d0524bc 100644
> --- a/arch/arm/mach-digic/Kconfig
> +++ b/arch/arm/mach-digic/Kconfig
> @@ -16,4 +16,7 @@ config ARCH_TEXT_BASE
>  config DIGIC_CSRC_TIMER
>  	bool
>  
> +config DIGIC_CSRC_DUMMY
> +	bool
> +
>  endif
> diff --git a/arch/arm/mach-digic/Makefile b/arch/arm/mach-digic/Makefile
> index 1d7cb72..31e5ac1 100644
> --- a/arch/arm/mach-digic/Makefile
> +++ b/arch/arm/mach-digic/Makefile
> @@ -1,2 +1,3 @@
>  obj-y += core.o
>  obj-$(CONFIG_DIGIC_CSRC_TIMER) += csrc-timer.o
> +obj-$(CONFIG_DIGIC_CSRC_DUMMY) += csrc-dummy.o
> diff --git a/arch/arm/mach-digic/csrc-dummy.c b/arch/arm/mach-digic/csrc-dummy.c
> new file mode 100644
> index 0000000..68c68a3
> --- /dev/null
> +++ b/arch/arm/mach-digic/csrc-dummy.c
> @@ -0,0 +1,49 @@
> +/*
> + * Copyright (C) 2013 Antony Pavlov <antonynpavlov@gmail.com>
> + *
> + * This file is part of barebox.
> + * See file CREDITS for list of people who contributed to this project.
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <init.h>
> +#include <clock.h>
> +
> +#include <stdio.h>
> +
> +static uint64_t dummy_counter;
> +
> +static uint64_t dummy_cs_read(void)
> +{
> +	dummy_counter += 2000;
> +	return dummy_counter;
> +}
> +
So if I understand it right, you assume here that the instructions to
read this value will take 0.02 ms?

- Alex

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