[PATCH 1/7] Add generic poll infrastructure

[Sascha Hauer]

Hi Marc (Kleine-Budde),

I took the version of this patch I had lying around, please let
me know if you have an updated version.

Sascha

On Sat, Dec 18, 2010 at 04:15:03PM +0100, Sascha Hauer wrote:
> From: Marc Kleine-Budde <mkl at pengutronix.de>
> 
> Barebox does not have interrupt functionality. Nevertheless it's
> sometimes useful to periodically call functions, like for example
> a heartbeat LED or watchdog reset. Instead of cluttering the code
> with calls to these functions this patch adds a generic polling
> infrastructure. Code which might run for longer now can call
> poller_call() periodically which in turn will call all registered
> pollers.
> This patch adds a call to poller_call in two generic pathes. First
> of them is getc() which covers waiting for uart input. Second is
> ctrlc() which should be called anyway from code which might run
> for longer. So instead adding poller_call directly to your code,
> consider checking ctrlc instead which also gives additional
> convenience to the user.
> The poller code is safe against reentrancy which means that it's
> safe to call poller_call inside a poller.
> 
> Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
>  common/Kconfig   |    3 +++
>  common/Makefile  |    1 +
>  common/console.c |    5 +++++
>  common/poller.c  |   45 +++++++++++++++++++++++++++++++++++++++++++++
>  include/poller.h |   31 +++++++++++++++++++++++++++++++
>  5 files changed, 85 insertions(+), 0 deletions(-)
>  create mode 100644 common/poller.c
>  create mode 100644 include/poller.h
> 
> diff --git a/common/Kconfig b/common/Kconfig
> index 617f640..02bc67e 100644
> --- a/common/Kconfig
> +++ b/common/Kconfig
> @@ -414,6 +414,9 @@ config DEFAULT_ENVIRONMENT_PATH
>  	  Relative pathes will be relative to the barebox Toplevel dir, but absolute
>  	  pathes are fine aswell.
>  
> +config POLLER
> +	bool "generic polling infrastructure"
> +
>  endmenu
>  
>  menu "Debugging                     "
> diff --git a/common/Makefile b/common/Makefile
> index 753455b..98c9d36 100644
> --- a/common/Makefile
> +++ b/common/Makefile
> @@ -5,6 +5,7 @@ obj-$(CONFIG_OF_FLAT_TREE)	+= ft_build.o
>  obj-$(CONFIG_KALLSYMS)		+= kallsyms.o
>  obj-$(CONFIG_ENV_HANDLING)	+= environment.o
>  obj-$(CONFIG_AUTO_COMPLETE)	+= complete.o
> +obj-$(CONFIG_POLLER)		+= poller.o
>  
>  obj-y += dlmalloc.o
>  obj-y += clock.o
> diff --git a/common/console.c b/common/console.c
> index 82786f2..39ead4b 100644
> --- a/common/console.c
> +++ b/common/console.c
> @@ -34,6 +34,7 @@
>  #include <clock.h>
>  #include <kfifo.h>
>  #include <module.h>
> +#include <poller.h>
>  #include <linux/list.h>
>  
>  LIST_HEAD(console_list);
> @@ -205,6 +206,8 @@ int getc(void)
>  	 */
>  	start = get_time_ns();
>  	while (1) {
> +		poller_call();
> +
>  		if (tstc()) {
>  			kfifo_putc(console_input_buffer, getc_raw());
>  
> @@ -397,6 +400,8 @@ EXPORT_SYMBOL(vprintf);
>  /* test if ctrl-c was pressed */
>  int ctrlc (void)
>  {
> +	poller_call();
> +
>  	if (tstc() && getc() == 3)
>  		return 1;
>  	return 0;
> diff --git a/common/poller.c b/common/poller.c
> new file mode 100644
> index 0000000..0583a53
> --- /dev/null
> +++ b/common/poller.c
> @@ -0,0 +1,45 @@
> +/*
> + * Copyright (C) 2010 Marc Kleine-Budde <mkl at pengutronix.de>
> + *
> + * This file is released under the GPLv2
> + *
> + */
> +
> +#include <common.h>
> +#include <driver.h>
> +#include <malloc.h>
> +#include <module.h>
> +#include <param.h>
> +#include <poller.h>
> +
> +static LIST_HEAD(poller_list);
> +static int poller_active;
> +
> +int poller_register(struct poller_struct *poller)
> +{
> +	list_add_tail(&poller->list, &poller_list);
> +
> +	return 0;
> +}
> +
> +int poller_unregister(struct poller_struct *poller)
> +{
> +	list_del(&poller->list);
> +
> +	return 0;
> +}
> +
> +void poller_call(void)
> +{
> +	struct poller_struct *poller, *tmp;
> +
> +	if (poller_active)
> +		return;
> +
> +	poller_active = 1;
> +
> +	list_for_each_entry_safe(poller, tmp, &poller_list, list)
> +		poller->func(poller);
> +
> +	poller_active = 0;
> +}
> diff --git a/include/poller.h b/include/poller.h
> new file mode 100644
> index 0000000..dc98155
> --- /dev/null
> +++ b/include/poller.h
> @@ -0,0 +1,31 @@
> +/*
> + * Copyright (C) 2010 Marc Kleine-Budde <mkl at pengutronix.de>
> + *
> + * This file is released under the GPLv2
> + *
> + */
> +
> +#ifndef POLLER_H
> +#define POLLER_H
> +
> +#include <linux/list.h>
> +
> +struct poller_struct {
> +	void (*func)(struct poller_struct *poller);
> +
> +	struct list_head list;
> +};
> +
> +int poller_register(struct poller_struct *poller);
> +int poller_unregister(struct poller_struct *poller);
> +
> +
> +#ifdef CONFIG_POLLER
> +void poller_call(void);
> +#else
> +static inline void poller_call(void)
> +{
> +}
> +#endif	/* CONFIG_POLLER */
> +
> +#endif	/* !POLLER_H */
> -- 
> 1.7.2.3
> 
> 

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