[PATCH] of: Add missing node iteration stubs for disabled CONFIG_OF
Jonathan Austin
jonathan.austin at arm.com
Wed Jun 12 06:10:49 EDT 2013
On 11/06/13 22:51, Grant Likely wrote:
> On Tue, 11 Jun 2013 17:22:55 +0100, Jonathan Austin <jonathan.austin at arm.com> wrote:
>> Hi Rob, Thomasz,
>>
>> (dredging up an oldish thread as I just ran in to this issue)
>>
>> On 01/04/13 22:19, Rob Herring wrote:
>>> On 03/09/2013 02:15 PM, Tomasz Figa wrote:
>>>> This patch moves several for_each macros out of the #ifdef CONFIG_OF
>>>> block and adds inline stubs for functions used by these macros, compiled
>>>> conditionally when CONFIG_OF is not enabled.
>>>>
>>>> This eliminates the need to explicitly check for CONFIG_OF in driver
>>>> code using mentioned functions and macros.
>>>
>>> Do you have some users of this?
>>
>> I do!
>>
>> Or at least I might.
>>
>> I'm not certain as perhaps the fix to what I describe below is to add
>> dependencies on CONFIG_OF - it isn't clear to me either way:
>>
>> With both psci and arch_timers (CONFIG_ARM_PSCI, CONFIG_ARM_ARCH_TIMER)
>> and without CONFIG_OF we get a build failure because we lack the definition
>> of of_find_matching_node():
>>
>> eg:
>> arch/arm/kernel/psci.c:167:2: error: implicit declaration of function ‘of_find_matching_node’ [-Werror=implicit-function-declaration]
>>
>> The same happens with arm_arch_timer.c (well, there's a patch required to
>> include linux/of.h first, after which Thomasz's patch is relevant).
>
> That code path is completely broken if CONFIG_OF is not set. psci_init()
> is nothing but calls to CONFIG_OF infrastructure! I think that code
Well, it looks like the intention of that code was to just behave like
there was no relevant node in the case the CONFIG_OF was disabled:
np = of_find_matching_node(NULL, psci_of_match);
if (!np)
return 0;
If of_find_matching() node behaved like of_match_node() then nothing
would be 'broken' per se, but we would have a bunch of useless code
compiled in to our kernel.
> needs to depend on CONFIG_OF, or at least be wrapped with
> "if (IS_ENABLED(CONFIG_OF))" if there are still usable parts when
> CONFIG_OF is disabled. Frankly I don't see that as being a real concern.
Indeed, despite the clarification above, I think it'd be fine to not
build these without CONFIG_OF.
I'm happy to submit a patches to add dependencies on CONFIG_OF for
ARM_ARCH_TIMER and ARM_PSCI - I don't think either of those will get any
complaints because as you say, neither makes very much sense without a
DT to specify them.
Thanks,
Jonny
>
> That said, Arnd has posted a patch that moves at least some of the function
> prototypes out from under the #ifdef block so that GCC can do syntax
> checking on disabled code. That overlaps a bit with this patch.
>
> Regardless, I'm not going to apply it without a legitimate (as opposed
> to theoretical) user.
>
> g.
>
>> So, I guess the question is whether we should expect PSCI and ARM_ARCH_TIMER
>> to depend on CONFIG_OF, or whether we'd like them to fail gracefully in the
>> case that we *don't* have CONFIG_OF. I think the current situation is broken
>> either way...
>>
>> Thoughts?
>>
>> Jonny
>>
>>>
>>> Rob
>>>
>>>>
>>>> Signed-off-by: Tomasz Figa <tomasz.figa at gmail.com>
>>>> ---
>>>> include/linux/of.h | 92 +++++++++++++++++++++++++++++++++++++-----------------
>>>> 1 file changed, 63 insertions(+), 29 deletions(-)
>>>>
>>>> diff --git a/include/linux/of.h b/include/linux/of.h
>>>> index a0f1292..7a736b8 100644
>>>> --- a/include/linux/of.h
>>>> +++ b/include/linux/of.h
>>>> @@ -86,6 +86,31 @@ static inline struct device_node *of_node_get(struct device_node *node)
>>>> static inline void of_node_put(struct device_node *node) { }
>>>> #endif /* !CONFIG_OF_DYNAMIC */
>>>>
>>>> +#define for_each_node_by_name(dn, name) \
>>>> + for (dn = of_find_node_by_name(NULL, name); dn; \
>>>> + dn = of_find_node_by_name(dn, name))
>>>> +#define for_each_node_by_type(dn, type) \
>>>> + for (dn = of_find_node_by_type(NULL, type); dn; \
>>>> + dn = of_find_node_by_type(dn, type))
>>>> +#define for_each_compatible_node(dn, type, compatible) \
>>>> + for (dn = of_find_compatible_node(NULL, type, compatible); dn; \
>>>> + dn = of_find_compatible_node(dn, type, compatible))
>>>> +#define for_each_matching_node(dn, matches) \
>>>> + for (dn = of_find_matching_node(NULL, matches); dn; \
>>>> + dn = of_find_matching_node(dn, matches))
>>>> +#define for_each_matching_node_and_match(dn, matches, match) \
>>>> + for (dn = of_find_matching_node_and_match(NULL, matches, match); \
>>>> + dn; dn = of_find_matching_node_and_match(dn, matches, match))
>>>> +#define for_each_child_of_node(parent, child) \
>>>> + for (child = of_get_next_child(parent, NULL); child != NULL; \
>>>> + child = of_get_next_child(parent, child))
>>>> +#define for_each_available_child_of_node(parent, child) \
>>>> + for (child = of_get_next_available_child(parent, NULL); child != NULL; \
>>>> + child = of_get_next_available_child(parent, child))
>>>> +#define for_each_node_with_property(dn, prop_name) \
>>>> + for (dn = of_find_node_with_property(NULL, prop_name); dn; \
>>>> + dn = of_find_node_with_property(dn, prop_name))
>>>> +
>>>> #ifdef CONFIG_OF
>>>>
>>>> /* Pointer for first entry in chain of all nodes. */
>>>> @@ -167,19 +192,10 @@ static inline const char *of_node_full_name(const struct device_node *np)
>>>>
>>>> extern struct device_node *of_find_node_by_name(struct device_node *from,
>>>> const char *name);
>>>> -#define for_each_node_by_name(dn, name) \
>>>> - for (dn = of_find_node_by_name(NULL, name); dn; \
>>>> - dn = of_find_node_by_name(dn, name))
>>>> extern struct device_node *of_find_node_by_type(struct device_node *from,
>>>> const char *type);
>>>> -#define for_each_node_by_type(dn, type) \
>>>> - for (dn = of_find_node_by_type(NULL, type); dn; \
>>>> - dn = of_find_node_by_type(dn, type))
>>>> extern struct device_node *of_find_compatible_node(struct device_node *from,
>>>> const char *type, const char *compat);
>>>> -#define for_each_compatible_node(dn, type, compatible) \
>>>> - for (dn = of_find_compatible_node(NULL, type, compatible); dn; \
>>>> - dn = of_find_compatible_node(dn, type, compatible))
>>>> extern struct device_node *of_find_matching_node_and_match(
>>>> struct device_node *from,
>>>> const struct of_device_id *matches,
>>>> @@ -190,12 +206,6 @@ static inline struct device_node *of_find_matching_node(
>>>> {
>>>> return of_find_matching_node_and_match(from, matches, NULL);
>>>> }
>>>> -#define for_each_matching_node(dn, matches) \
>>>> - for (dn = of_find_matching_node(NULL, matches); dn; \
>>>> - dn = of_find_matching_node(dn, matches))
>>>> -#define for_each_matching_node_and_match(dn, matches, match) \
>>>> - for (dn = of_find_matching_node_and_match(NULL, matches, match); \
>>>> - dn; dn = of_find_matching_node_and_match(dn, matches, match))
>>>> extern struct device_node *of_find_node_by_path(const char *path);
>>>> extern struct device_node *of_find_node_by_phandle(phandle handle);
>>>> extern struct device_node *of_get_parent(const struct device_node *node);
>>>> @@ -207,14 +217,6 @@ extern struct device_node *of_get_next_available_child(
>>>>
>>>> extern struct device_node *of_get_child_by_name(const struct device_node *node,
>>>> const char *name);
>>>> -#define for_each_child_of_node(parent, child) \
>>>> - for (child = of_get_next_child(parent, NULL); child != NULL; \
>>>> - child = of_get_next_child(parent, child))
>>>> -
>>>> -#define for_each_available_child_of_node(parent, child) \
>>>> - for (child = of_get_next_available_child(parent, NULL); child != NULL; \
>>>> - child = of_get_next_available_child(parent, child))
>>>> -
>>>> static inline int of_get_child_count(const struct device_node *np)
>>>> {
>>>> struct device_node *child;
>>>> @@ -228,10 +230,6 @@ static inline int of_get_child_count(const struct device_node *np)
>>>>
>>>> extern struct device_node *of_find_node_with_property(
>>>> struct device_node *from, const char *prop_name);
>>>> -#define for_each_node_with_property(dn, prop_name) \
>>>> - for (dn = of_find_node_with_property(NULL, prop_name); dn; \
>>>> - dn = of_find_node_with_property(dn, prop_name))
>>>> -
>>>> extern struct property *of_find_property(const struct device_node *np,
>>>> const char *name,
>>>> int *lenp);
>>>> @@ -353,13 +351,28 @@ static inline struct device_node *of_find_node_by_name(struct device_node *from,
>>>> return NULL;
>>>> }
>>>>
>>>> +static inline struct device_node *of_find_node_by_type(struct device_node *from,
>>>> + const char *type)
>>>> +{
>>>> + return NULL;
>>>> +}
>>>> +
>>>> static inline bool of_have_populated_dt(void)
>>>> {
>>>> return false;
>>>> }
>>>>
>>>> -#define for_each_child_of_node(parent, child) \
>>>> - while (0)
>>>> +static inline struct device_node *of_get_next_child(const struct device_node *node,
>>>> + struct device_node *prev)
>>>> +{
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +static inline struct device_node *of_get_next_available_child(
>>>> + const struct device_node *node, struct device_node *prev)
>>>> +{
>>>> + return NULL;
>>>> +}
>>>>
>>>> static inline struct device_node *of_get_child_by_name(
>>>> const struct device_node *node,
>>>> @@ -373,6 +386,12 @@ static inline int of_get_child_count(const struct device_node *np)
>>>> return 0;
>>>> }
>>>>
>>>> +static inline struct device_node *of_find_node_with_property(
>>>> + struct device_node *from, const char *prop_name)
>>>> +{
>>>> + return NULL;
>>>> +}
>>>> +
>>>> static inline int of_device_is_compatible(const struct device_node *device,
>>>> const char *name)
>>>> {
>>>> @@ -394,6 +413,21 @@ static inline struct device_node *of_find_compatible_node(
>>>> return NULL;
>>>> }
>>>>
>>>> +static inline struct device_node *of_find_matching_node_and_match(
>>>> + struct device_node *from,
>>>> + const struct of_device_id *matches,
>>>> + const struct of_device_id **match)
>>>> +{
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +static inline struct device_node *of_find_matching_node(
>>>> + struct device_node *from,
>>>> + const struct of_device_id *matches)
>>>> +{
>>>> + return NULL;
>>>> +}
>>>> +
>>>> static inline int of_property_read_u8_array(const struct device_node *np,
>>>> const char *propname, u8 *out_values, size_t sz)
>>>> {
>>>>
>>>
>>>
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>>>
>>
>>
>>
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