On 29-12-16 10:43, Rafał Miłecki wrote:
> On 29 December 2016 at 09:57, Arend van Spriel
> <arend.vanspriel@xxxxxxxxxxxx> wrote:
>> On 28-12-16 22:30, Rafał Miłecki wrote:
>>> On 28 December 2016 at 22:28, Rafał Miłecki <zajec5@xxxxxxxxx> wrote:
>>>> On 28 December 2016 at 22:07, Arend van Spriel
>>>> <arend.vanspriel@xxxxxxxxxxxx> wrote:
>>>>> On 28-12-16 16:59, Rafał Miłecki wrote:
>>>>>> From: Rafał Miłecki <rafal@xxxxxxxxxx>
>>>>>>
>>>>>> They allow specifying hardware limitations of supported channels. This
>>>>>> may be useful for specifying single band devices or devices that support
>>>>>> only some part of the whole band.
>>>>>> E.g. some tri-band routers have separated radios for lower and higher
>>>>>> part of 5 GHz band.
>>>>>>
>>>>>> Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
>>>>>> ---
>>>>>> net/wireless/reg.c | 34 ++++++++++++++++++++++++++++++++++
>>>>>> 1 file changed, 34 insertions(+)
>>>>>>
>>>>>> diff --git a/net/wireless/reg.c b/net/wireless/reg.c
>>>>>> index 5dbac37..35ba5c7 100644
>>>>>> --- a/net/wireless/reg.c
>>>>>> +++ b/net/wireless/reg.c
>>>>>> @@ -1123,6 +1123,26 @@ const char *reg_initiator_name(enum nl80211_reg_initiator initiator)
>>>>>> }
>>>>>> EXPORT_SYMBOL(reg_initiator_name);
>>>>>>
>>>>>> +static bool reg_center_freq_of_valid(struct wiphy *wiphy,
>>>>>> + struct ieee80211_channel *chan)
>>>>>> +{
>>>>>> + struct device_node *np = wiphy_dev(wiphy)->of_node;
>>>>>> + u32 val;
>>>>>> +
>>>>>> + if (!np)
>>>>>> + return true;
>>>>>> +
>>>>>> + if (!of_property_read_u32(np, "ieee80211-min-center-freq", &val) &&
>>>>>> + chan->center_freq < KHZ_TO_MHZ(val))
>>>>>> + return false;
>>>>>> +
>>>>>> + if (!of_property_read_u32(np, "ieee80211-max-center-freq", &val) &&
>>>>>> + chan->center_freq > KHZ_TO_MHZ(val))
>>>>>> + return false;
>>>>>
>>>>> I suspect these functions rely on CONFIG_OF. So might not build for
>>>>> !CONFIG_OF.
>>>>
>>>> I compiled it with
>>>> # CONFIG_OF is not set
>>>>
>>>> Can you test it and provide a non-working config if you see a
>>>> compilation error, please?
>>>
>>> include/linux/of.h provides a lot of dummy static inline functions if
>>> CONFIG_OF is not used (they also allow compiler to drop most of the
>>> code).
>>
>> of_propeirty_read_u32 is static inline in of.h calling
>> of_property_read_u32_array, which has a dummy variant in of.h returning
>> -ENOSYS so -38. Pretty sure that is not what you want. At least it does
>> not allow the compiler to drop any code so probably better to do:
>>
>> if (!IS_ENABLED(CONFIG_OF) || !np)
>> return true;
>
> Please verify that using a compiler. If there is a problem I'll be
> happy to work on it, but I need a proof it exists.
I am on vacation right now so not having much more than email and web
browser to use as review reference.
> If compilers sees a:
> if (!-ENOSYS && chan->center_freq < KHZ_TO_MHZ(val))
> condition, it's pretty clear it can be dropped. With both conditional
> blocks dropped function always returns "true" and... can be dropped.
>
> Let me see if I can convince you with the following test:
No need to convince me. I made a mistake reviewing the code. Thanks for
clarifying it.
> $ grep -m 1 CONFIG_OF .config
> # CONFIG_OF is not set
> $ objdump --syms net/wireless/reg.o | grep -c reg_center_freq_of_valid
> 0
>
> $ grep -m 1 CONFIG_OF .config
> CONFIG_OF=y
> $ objdump --syms net/wireless/reg.o | grep -c reg_center_freq_of_valid
> 1
>
>
>> So with this patch you change the channel to DISABLED. I am not very
>> familiar with reg.c so do you know if this is done before or after
>> calling regulatory notifier in the driver. brcmfmac will enable channels
>> querying the device upon regulatory notifier call, which may undo the
>> behavior introduced by your patch.
>
> I'm not regulatory export, so I hope someone will review this patch.
> So far I can say it works for me after trying it on SR400ac with
> BCM43602.
But you probably do not have a mapping table for mapping country code
received in notifier to firmware regulatory code/revision. Only if you
have that, brcmfmac will update the channels in the bands.
Giving this some more consideration I am not sure if this is the proper
place to handle this. ieee80211-(min|max)-center-freq is platform
specific configuration allowing multiple cards to be used in different
(sub)bands. This has nothing to do with regulatory. So probably better
to move it to core.c or chan.c.
Regards,
Arend
