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 <[email protected]>
> ---
> 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
>
>
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