[PATCH 14/18] overlay: Add filters to choose which overlays to apply

[Michael Riesch]

Hello Sascha,

On 6/24/21 10:52 AM, Sascha Hauer wrote:
> [...]
> +
> +static int of_overlay_global_fixup(struct device_node *root, void *data)
> +{
> +	char *dir;
> +	int ret;
> +
> +	if (*of_overlay_dir == '/')
> +		return of_overlay_apply_dir(root, of_overlay_dir, true);
> +
> +	dir = concat_path_file(of_overlay_basedir, of_overlay_dir);
> +
> +	ret = of_overlay_apply_dir(root, of_overlay_dir, true);

shouldn't this be

	ret = of_overlay_apply_dir(root, dir, true);

in order to use the concatenated path?

Regards,
Michael

> +
> +	free(dir);
> +
> +	return ret;
> +}
> +
> +/**
> + * of_overlay_register_filter - register a new overlay filter
> + * @filter: The new filter
> + *
> + * Register a new overlay filter. A filter can either match on
> + * the filename or on the content of an overlay, but not on both.
> + * If that's desired two filters have to be registered.
> + *
> + * @return: 0 for success, negative error code otherwise
> + */
> +int of_overlay_register_filter(struct of_overlay_filter *filter)
> +{
> +	if (filter->filter_filename && filter->filter_content)
> +		return -EINVAL;
> +
> +	list_add_tail(&filter->list, &of_overlay_filters);
> +
> +	return 0;
> +}
> +
> +/**
> + * of_overlay_filter_filename - A filter that matches on the filename of
> + *                                an overlay
> + * @f: The filter
> + * @filename: The filename of the overlay
> + *
> + * This filter matches when the filename matches one of the patterns given
> + * in global.of.overlay.filepattern. global.of.overlay.filepattern shall
> + * contain a space separated list of wildcard patterns.
> + *
> + * @return: True when the overlay shall be applied, false otherwise.
> + */
> +static bool of_overlay_filter_filename(struct of_overlay_filter *f,
> +				       const char *filename)
> +{
> +	char *p, *path, *n;
> +	int ret;
> +	bool apply;
> +
> +	p = path = strdup(of_overlay_filepattern);
> +
> +	while ((n = strsep_unescaped(&p, " "))) {
> +		if (!*n)
> +			continue;
> +
> +		ret = fnmatch(n, filename, 0);
> +
> +		if (!ret) {
> +			apply = true;
> +			goto out;
> +		}
> +	}
> +
> +	apply = false;
> +out:
> +	free(path);
> +
> +	return apply;
> +}
> +
> +static struct of_overlay_filter of_overlay_filepattern_filter = {
> +	.name = "filepattern",
> +	.filter_filename = of_overlay_filter_filename,
> +};
> +
> +/**
> + * of_overlay_filter_compatible - A filter that matches on the compatible of
> + *                                an overlay
> + * @f: The filter
> + * @ovl: The overlay
> + *
> + * This filter matches when the compatible of an overlay matches to one
> + * of the compatibles given in global.of.overlay.compatible. When the
> + * overlay doesn't contain a compatible entry it is considered matching.
> + * Also when no compatibles are given in global.of.overlay.compatible
> + * all overlays will match.
> + *
> + * @return: True when the overlay shall be applied, false otherwise.
> + */
> +static bool of_overlay_filter_compatible(struct of_overlay_filter *f,
> +					struct device_node *ovl)
> +{
> +	char *p, *n, *compatibles;
> +	bool res = false;
> +
> +	if (!of_overlay_compatible || !*of_overlay_compatible)
> +		return true;
> +	if (!of_find_property(ovl, "compatible", NULL))
> +		return true;
> +
> +	p = compatibles = xstrdup(of_overlay_compatible);
> +
> +	while ((n = strsep_unescaped(&p, " "))) {
> +		if (!*n)
> +			continue;
> +
> +		if (of_device_is_compatible(ovl, n)) {
> +			res = true;
> +			break;
> +		}
> +	}
> +
> +	free(compatibles);
> +
> +	return res;
> +}
> +
> +static struct of_overlay_filter of_overlay_compatible_filter = {
> +	.name = "compatible",
> +	.filter_content = of_overlay_filter_compatible,
> +};
> +
> +static int of_overlay_init(void)
> +{
> +	of_overlay_filepattern = strdup("*");
> +	of_overlay_filter = strdup("filepattern compatible");
> +	of_overlay_set_basedir("/");
> +
> +	globalvar_add_simple_string("of.overlay.compatible", &of_overlay_compatible);
> +	globalvar_add_simple_string("of.overlay.filepattern", &of_overlay_filepattern);
> +	globalvar_add_simple_string("of.overlay.filter", &of_overlay_filter);
> +	globalvar_add_simple_string("of.overlay.dir", &of_overlay_dir);
> +
> +	of_overlay_register_filter(&of_overlay_filepattern_filter);
> +	of_overlay_register_filter(&of_overlay_compatible_filter);
> +
> +	of_register_fixup(of_overlay_global_fixup, NULL);
> +
> +	return 0;
> +}
> +device_initcall(of_overlay_init);
> +
> +BAREBOX_MAGICVAR(global.of.overlay.compatible, "space separated list of compatibles an overlay must match");
> +BAREBOX_MAGICVAR(global.of.overlay.filepattern, "space separated list of filepatterns an overlay must match");
> +BAREBOX_MAGICVAR(global.of.overlay.dir, "Directory to look for dt overlays");
> +BAREBOX_MAGICVAR(global.of.overlay.filter, "space separated list of filters");
> diff --git a/include/of.h b/include/of.h
> index 59c1250fb2..b698220b1e 100644
> --- a/include/of.h
> +++ b/include/of.h
> @@ -1022,12 +1022,20 @@ static inline struct device_node *of_find_root_node(struct device_node *node)
>  	return node;
>  }
>  
> +struct of_overlay_filter {
> +	bool (*filter_filename)(struct of_overlay_filter *, const char *filename);
> +	bool (*filter_content)(struct of_overlay_filter *, struct device_node *);
> +	char *name;
> +	struct list_head list;
> +};
> +
>  #ifdef CONFIG_OF_OVERLAY
>  struct device_node *of_resolve_phandles(struct device_node *root,
>  					const struct device_node *overlay);
>  int of_overlay_apply_tree(struct device_node *root,
>  			  struct device_node *overlay);
> -int of_overlay_apply_file(struct device_node *root, const char *filename);
> +int of_overlay_apply_file(struct device_node *root, const char *filename,
> +			  bool filter);
>  int of_register_overlay(struct device_node *overlay);
>  int of_process_overlay(struct device_node *root,
>  		    struct device_node *overlay,
> @@ -1038,6 +1046,8 @@ int of_process_overlay(struct device_node *root,
>  int of_overlay_pre_load_firmware(struct device_node *root, struct device_node *overlay);
>  int of_overlay_load_firmware(void);
>  void of_overlay_load_firmware_clear(void);
> +void of_overlay_set_basedir(const char *path);
> +int of_overlay_register_filter(struct of_overlay_filter *);
>  #else
>  static inline struct device_node *of_resolve_phandles(struct device_node *root,
>  					const struct device_node *overlay)
> @@ -1052,7 +1062,7 @@ static inline int of_overlay_apply_tree(struct device_node *root,
>  }
>  
>  static inline int of_overlay_apply_file(struct device_node *root,
> -					const char *filename)
> +					const char *filename, bool filter)
>  {
>  	return -ENOSYS;
>  }
> @@ -1086,6 +1096,10 @@ static inline void of_overlay_load_firmware_clear(void)
>  {
>  }
>  
> +static inline void of_overlay_set_basedir(const char *path)
> +{
> +}
> +
>  #endif
>  
>  #endif /* __OF_H */
>