On Fri, Nov 20, 2020 at 03:06:48PM +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@xxxxxxxxxxxxxx>
> ---
> 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(-)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 5b45c2023f3b..85a94f6ef159 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);
>
> +extern int of_alias_get_id_from(struct device_node *root, struct device_node *np,
> + const char *stem)
extern?
Sascha
--
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