On Wed, Oct 14, 2020 at 9:54 AM Richard Fitzgerald
<[email protected]> 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 <[email protected]>
> ---
> 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.
> + 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);
> + }
> +
> + 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
>
On 2020-10-14 19:39, Rob Herring wrote:
> On Wed, Oct 14, 2020 at 9:54 AM Richard Fitzgerald
> <[email protected]> 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 <[email protected]>
>> ---
>> 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
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
On Thu, Oct 15, 2020 at 11:52 AM Robin Murphy <[email protected]> wrote:
>
> On 2020-10-14 19:39, Rob Herring wrote:
> > On Wed, Oct 14, 2020 at 9:54 AM Richard Fitzgerald
> > <[email protected]> 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 <[email protected]>
> >> ---
> >> 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 :/
Indeed. We should just generalize this. It can still be refactored to
shared code.
It's probably worthwhile to check for a remainder here IMO.
Rob