Re: [PATCH v2 1/2] watchdog: implement watchdog_get_alias_id_from

[Sascha Hauer <sha@pengutronix.de>]

On Tue, Nov 24, 2020 at 11:24:29AM +0100, Ahmad Fatoum wrote:
> On device-tree enabled platforms, the Linux kernel will first attempt
> to use watchdog%d as watchdog name, where %d is the alias id.
> 
> Add a function that given a barebox struct watchdog and the device tree
> root node of the kernel device tree, computes the corresponding kernel
> alias id.
> 
> This may then later be used to pass an appropriate argument on the
> kernel command line.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> v1 -> v2:
>   - removed extern where unneeded (Sascha)
> ---
>  drivers/of/base.c          | 77 ++++++++++++++++++++++++++++++--------
>  drivers/watchdog/wd_core.c | 19 ++++++++++
>  include/of.h               |  8 ++++
>  include/watchdog.h         |  8 ++++
>  4 files changed, 97 insertions(+), 15 deletions(-)

Applied, thanks

Sascha

> 
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 5b45c2023f3b..acbae3d8c4bb 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -149,6 +149,31 @@ static void of_alias_add(struct alias_prop *ap, struct device_node *np,
>  		 ap->alias, ap->stem, ap->id, np->full_name);
>  }
>  
> +static struct device_node *of_alias_resolve(struct device_node *root, struct property *pp)
> +{
> +	/* Skip those we do not want to proceed */
> +	if (!of_prop_cmp(pp->name, "name") ||
> +	    !of_prop_cmp(pp->name, "phandle") ||
> +	    !of_prop_cmp(pp->name, "linux,phandle"))
> +		return NULL;
> +
> +	return of_find_node_by_path_from(root, of_property_get_value(pp));
> +}
> +
> +static int of_alias_id_parse(const char *start, int *len)
> +{
> +	const char *end = start + strlen(start);
> +
> +	/* walk the alias backwards to extract the id and work out
> +	 * the 'stem' string */
> +	while (isdigit(*(end-1)) && end > start)
> +		end--;
> +
> +	*len = end - start;
> +
> +	return simple_strtol(end, NULL, 10);
> +}
> +
>  /**
>   * of_alias_scan - Scan all properties of 'aliases' node
>   *
> @@ -175,28 +200,15 @@ void of_alias_scan(void)
>  
>  	list_for_each_entry(pp, &of_aliases->properties, list) {
>  		const char *start = pp->name;
> -		const char *end = start + strlen(start);
>  		struct device_node *np;
>  		struct alias_prop *ap;
>  		int id, len;
>  
> -		/* Skip those we do not want to proceed */
> -		if (!of_prop_cmp(pp->name, "name") ||
> -		    !of_prop_cmp(pp->name, "phandle") ||
> -		    !of_prop_cmp(pp->name, "linux,phandle"))
> -			continue;
> -
> -		np = of_find_node_by_path(of_property_get_value(pp));
> +		np = of_alias_resolve(root_node, pp);
>  		if (!np)
>  			continue;
>  
> -		/* walk the alias backwards to extract the id and work out
> -		 * the 'stem' string */
> -		while (isdigit(*(end-1)) && end > start)
> -			end--;
> -		len = end - start;
> -
> -		id = simple_strtol(end, NULL, 10);
> +		id = of_alias_id_parse(start, &len);
>  		if (id < 0)
>  			continue;
>  
> @@ -235,6 +247,41 @@ int of_alias_get_id(struct device_node *np, const char *stem)
>  }
>  EXPORT_SYMBOL_GPL(of_alias_get_id);
>  
> +int of_alias_get_id_from(struct device_node *root, struct device_node *np,
> +			 const char *stem)
> +{
> +	struct device_node *aliasnp, *entrynp;
> +	struct property *pp;
> +
> +	if (!root)
> +		return of_alias_get_id(np, stem);
> +
> +	aliasnp = of_find_node_by_path_from(root, "/aliases");
> +	if (!aliasnp)
> +		return -ENODEV;
> +
> +	for_each_property_of_node(aliasnp, pp) {
> +		const char *start = pp->name;
> +		int id, len;
> +
> +		entrynp = of_alias_resolve(root_node, pp);
> +		if (entrynp != np)
> +			continue;
> +
> +		id = of_alias_id_parse(start, &len);
> +		if (id < 0)
> +			continue;
> +
> +		if (strncasecmp(start, stem, len))
> +			continue;
> +
> +		return id;
> +	}
> +
> +	return -ENODEV;
> +}
> +EXPORT_SYMBOL_GPL(of_alias_get_id_from);
> +
>  const char *of_alias_get(struct device_node *np)
>  {
>  	struct alias_prop *app;
> diff --git a/drivers/watchdog/wd_core.c b/drivers/watchdog/wd_core.c
> index 665338af6197..643c53268fc8 100644
> --- a/drivers/watchdog/wd_core.c
> +++ b/drivers/watchdog/wd_core.c
> @@ -261,6 +261,25 @@ struct watchdog *watchdog_get_default(void)
>  }
>  EXPORT_SYMBOL(watchdog_get_default);
>  
> +int watchdog_get_alias_id_from(struct watchdog *wd, struct device_node *root)
> +{
> +	struct device_node *dstnp, *srcnp = wd->hwdev ? wd->hwdev->device_node : NULL;
> +	char *name;
> +
> +	if (!srcnp)
> +		return -ENODEV;
> +
> +	name = of_get_reproducible_name(srcnp);
> +	dstnp = of_find_node_by_reproducible_name(root, name);
> +	free(name);
> +
> +	if (!dstnp)
> +		return -ENODEV;
> +
> +	return of_alias_get_id_from(root, wd->hwdev->device_node, "watchdog");
> +}
> +EXPORT_SYMBOL(watchdog_get_alias_id_from);
> +
>  struct watchdog *watchdog_get_by_name(const char *name)
>  {
>  	struct watchdog *tmp;
> diff --git a/include/of.h b/include/of.h
> index 08a02e110522..dc3aa0730bf7 100644
> --- a/include/of.h
> +++ b/include/of.h
> @@ -254,6 +254,8 @@ extern int of_count_phandle_with_args(const struct device_node *np,
>  
>  extern void of_alias_scan(void);
>  extern int of_alias_get_id(struct device_node *np, const char *stem);
> +extern int of_alias_get_id_from(struct device_node *root, struct device_node *np,
> +				const char *stem);
>  extern const char *of_alias_get(struct device_node *np);
>  extern int of_modalias_node(struct device_node *node, char *modalias, int len);
>  
> @@ -677,6 +679,12 @@ static inline int of_alias_get_id(struct device_node *np, const char *stem)
>  	return -ENOSYS;
>  }
>  
> +static inline int of_alias_get_id_from(struct device_node *root, struct device_node *np,
> +				       const char *stem)
> +{
> +	return -ENOSYS
> +}
> +
>  static inline const char *of_alias_get(struct device_node *np)
>  {
>  	return NULL;
> diff --git a/include/watchdog.h b/include/watchdog.h
> index 81414ef8ecaa..ee8efdecd030 100644
> --- a/include/watchdog.h
> +++ b/include/watchdog.h
> @@ -13,6 +13,8 @@ enum wdog_hw_runnning {
>  	 WDOG_HW_NOT_RUNNING = PARAM_TRISTATE_FALSE
>  };
>  
> +struct device_node;
> +
>  struct watchdog {
>  	int (*set_timeout)(struct watchdog *, unsigned);
>  	const char *name;
> @@ -44,6 +46,7 @@ int watchdog_register(struct watchdog *);
>  int watchdog_deregister(struct watchdog *);
>  struct watchdog *watchdog_get_default(void);
>  struct watchdog *watchdog_get_by_name(const char *name);
> +int watchdog_get_alias_id_from(struct watchdog *, struct device_node *);
>  int watchdog_set_timeout(struct watchdog*, unsigned);
>  int watchdog_inhibit_all(void);
>  #else
> @@ -76,6 +79,11 @@ static inline int watchdog_inhibit_all(void)
>  {
>  	return -ENOSYS;
>  }
> +
> +static inline int watchdog_get_alias_id_from(struct watchdog *, struct device_node *)
> +{
> +	return -ENOSYS;
> +}
>  #endif
>  
>  #define WATCHDOG_DEFAULT_PRIORITY 100
> -- 
> 2.29.2
> 
> 
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox