On 2020-10-14 19:39, Rob Herring wrote:
On Wed, Oct 14, 2020 at 9:54 AM Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx> wrote:Add an equivalent of of_count_phandle_with_args() for fixed argument sets, to pair with of_parse_phandle_with_fixed_args(). Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx> --- drivers/of/base.c | 42 ++++++++++++++++++++++++++++++++++++++++++ include/linux/of.h | 9 +++++++++ 2 files changed, 51 insertions(+) diff --git a/drivers/of/base.c b/drivers/of/base.c index ea44fea99813..45d8b0e65345 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -1772,6 +1772,48 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na } EXPORT_SYMBOL(of_count_phandle_with_args); +/** + * of_count_phandle_with_fixed_args() - Find the number of phandles references in a property + * @np: pointer to a device tree node containing a list + * @list_name: property name that contains a list + * @cell_count: number of argument cells following the phandle + * + * Returns the number of phandle + argument tuples within a property. It + * is a typical pattern to encode a list of phandle and variable + * arguments into a single property. + */ +int of_count_phandle_with_fixed_args(const struct device_node *np, + const char *list_name, + int cells_count) +{Looks to me like you can refactor of_count_phandle_with_args to handle both case and then make this and of_count_phandle_with_args simple wrapper functions.
Although for just counting the number of phandles each with n arguments that a property contains, isn't that simply a case of dividing the property length by n + 1? The phandles themselves will be validated by any subsequent of_parse_phandle*() call anyway, so there doesn't seem much point in doing more work then necessary here.
+ struct of_phandle_iterator it; + int rc, cur_index = 0; + + if (!cells_count) { + const __be32 *list; + int size; + + list = of_get_property(np, list_name, &size); + if (!list) + return -ENOENT; + + return size / sizeof(*list);
Case in point - if it's OK to do exactly that for n == 0, then clearly we're *aren't* fussed about validating anything, so the n > 0 code below is nothing more than a massively expensive way to check for a nonzero remainder :/
Robin.
+ } + + rc = of_phandle_iterator_init(&it, np, list_name, NULL, cells_count); + if (rc) + return rc; + + while ((rc = of_phandle_iterator_next(&it)) == 0) + cur_index += 1; + + if (rc != -ENOENT) + return rc; + + return cur_index; +} +EXPORT_SYMBOL(of_count_phandle_with_fixed_args); + /** * __of_add_property - Add a property to a node without lock operations */ diff --git a/include/linux/of.h b/include/linux/of.h index 5cf7ae0465d1..9f315da4e9da 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -377,6 +377,8 @@ extern int of_parse_phandle_with_fixed_args(const struct device_node *np, struct of_phandle_args *out_args); extern int of_count_phandle_with_args(const struct device_node *np, const char *list_name, const char *cells_name); +extern int of_count_phandle_with_fixed_args(const struct device_node *np, + const char *list_name, int cells_count); /* phandle iterator functions */ extern int of_phandle_iterator_init(struct of_phandle_iterator *it, @@ -886,6 +888,13 @@ static inline int of_count_phandle_with_args(struct device_node *np, return -ENOSYS; } +static inline int of_count_phandle_with_fixed_args(const struct device_node *np, + const char *list_name, + int cells_count) +{ + return -ENOSYS; +} + static inline int of_phandle_iterator_init(struct of_phandle_iterator *it, const struct device_node *np, const char *list_name, -- 2.20.1_______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
