diff mbox

[2/2] cfg80211: reg: support ieee80211-(min|max)-center-freq DT properties

Message ID 20161228155955.25518-2-zajec5@gmail.com (mailing list archive)
State Changes Requested
Delegated to: Johannes Berg
Headers show

Commit Message

Rafał Miłecki Dec. 28, 2016, 3:59 p.m. UTC
From: Rafał Miłecki <rafal@milecki.pl>

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@milecki.pl>
---
 net/wireless/reg.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

Comments

Arend van Spriel Dec. 28, 2016, 9:07 p.m. UTC | #1
On 28-12-16 16:59, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@milecki.pl>
> 
> 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@milecki.pl>
> ---
>  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.

Regards,
Arend
Rafał Miłecki Dec. 28, 2016, 9:28 p.m. UTC | #2
On 28 December 2016 at 22:07, Arend van Spriel
<arend.vanspriel@broadcom.com> wrote:
> On 28-12-16 16:59, Rafał Miłecki wrote:
>> From: Rafał Miłecki <rafal@milecki.pl>
>>
>> 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@milecki.pl>
>> ---
>>  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?
Rafał Miłecki Dec. 28, 2016, 9:30 p.m. UTC | #3
On 28 December 2016 at 22:28, Rafał Miłecki <zajec5@gmail.com> wrote:
> On 28 December 2016 at 22:07, Arend van Spriel
> <arend.vanspriel@broadcom.com> wrote:
>> On 28-12-16 16:59, Rafał Miłecki wrote:
>>> From: Rafał Miłecki <rafal@milecki.pl>
>>>
>>> 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@milecki.pl>
>>> ---
>>>  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).
Arend van Spriel Dec. 29, 2016, 8:57 a.m. UTC | #4
On 28-12-16 22:30, Rafał Miłecki wrote:
> On 28 December 2016 at 22:28, Rafał Miłecki <zajec5@gmail.com> wrote:
>> On 28 December 2016 at 22:07, Arend van Spriel
>> <arend.vanspriel@broadcom.com> wrote:
>>> On 28-12-16 16:59, Rafał Miłecki wrote:
>>>> From: Rafał Miłecki <rafal@milecki.pl>
>>>>
>>>> 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@milecki.pl>
>>>> ---
>>>>  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;

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.

Regards,
Arend
Rafał Miłecki Dec. 29, 2016, 9:43 a.m. UTC | #5
On 29 December 2016 at 09:57, Arend van Spriel
<arend.vanspriel@broadcom.com> wrote:
> On 28-12-16 22:30, Rafał Miłecki wrote:
>> On 28 December 2016 at 22:28, Rafał Miłecki <zajec5@gmail.com> wrote:
>>> On 28 December 2016 at 22:07, Arend van Spriel
>>> <arend.vanspriel@broadcom.com> wrote:
>>>> On 28-12-16 16:59, Rafał Miłecki wrote:
>>>>> From: Rafał Miłecki <rafal@milecki.pl>
>>>>>
>>>>> 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@milecki.pl>
>>>>> ---
>>>>>  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.

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:

$ 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.

ieee80211-min-center-freq = <2437000>;

[   11.986941] cfg80211: Disabling freq 2412 MHz as it's out of OF limits
[   12.000466] cfg80211: Disabling freq 2417 MHz as it's out of OF limits
[   12.013984] cfg80211: Disabling freq 2422 MHz as it's out of OF limits
[   12.027497] cfg80211: Disabling freq 2427 MHz as it's out of OF limits
[   12.041012] cfg80211: Disabling freq 2432 MHz as it's out of OF limits

root@lede:/# iw phy phy0 channels
Band 1:
        * 2412 MHz [1] (disabled)
        * 2417 MHz [2] (disabled)
        * 2422 MHz [3] (disabled)
        * 2427 MHz [4] (disabled)
        * 2432 MHz [5] (disabled)
        * 2437 MHz [6]
          Maximum TX power: 20.0 dBm
          Channel widths: 20MHz HT40- HT40+
        * 2442 MHz [7]
          Maximum TX power: 20.0 dBm
          Channel widths: 20MHz HT40- HT40+
        * 2447 MHz [8]
          Maximum TX power: 20.0 dBm
          Channel widths: 20MHz HT40-
        * 2452 MHz [9]
          Maximum TX power: 20.0 dBm
          Channel widths: 20MHz HT40-
        * 2457 MHz [10]
          Maximum TX power: 20.0 dBm
          Channel widths: 20MHz HT40-
        * 2462 MHz [11]
          Maximum TX power: 20.0 dBm
          Channel widths: 20MHz HT40-
        * 2467 MHz [12] (disabled)
        * 2472 MHz [13] (disabled)
        * 2484 MHz [14] (disabled)
Arend van Spriel Dec. 30, 2016, 8:20 p.m. UTC | #6
On 29-12-16 10:43, Rafał Miłecki wrote:
> On 29 December 2016 at 09:57, Arend van Spriel
> <arend.vanspriel@broadcom.com> wrote:
>> On 28-12-16 22:30, Rafał Miłecki wrote:
>>> On 28 December 2016 at 22:28, Rafał Miłecki <zajec5@gmail.com> wrote:
>>>> On 28 December 2016 at 22:07, Arend van Spriel
>>>> <arend.vanspriel@broadcom.com> wrote:
>>>>> On 28-12-16 16:59, Rafał Miłecki wrote:
>>>>>> From: Rafał Miłecki <rafal@milecki.pl>
>>>>>>
>>>>>> 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@milecki.pl>
>>>>>> ---
>>>>>>  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
Rafał Miłecki Dec. 30, 2016, 9:37 p.m. UTC | #7
On 30 December 2016 at 21:20, Arend van Spriel
<arend.vanspriel@broadcom.com> wrote:
> On 29-12-16 10:43, Rafał Miłecki wrote:
>> On 29 December 2016 at 09:57, Arend van Spriel
>> <arend.vanspriel@broadcom.com> wrote:
>>> On 28-12-16 22:30, Rafał Miłecki wrote:
>>>> On 28 December 2016 at 22:28, Rafał Miłecki <zajec5@gmail.com> wrote:
>>>>> On 28 December 2016 at 22:07, Arend van Spriel
>>>>> <arend.vanspriel@broadcom.com> wrote:
>>>>>> On 28-12-16 16:59, Rafał Miłecki wrote:
>>>>>>> From: Rafał Miłecki <rafal@milecki.pl>
>>>>>>>
>>>>>>> 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@milecki.pl>
>>>>>>> ---
>>>>>>>  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.

Thanks, I'll redo my tests.


> 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.

I can see point in this, I'll see if I can put this code in a more
proper place. Thanks for your comment!
diff mbox

Patch

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;
+
+	return true;
+}
+
 static uint32_t reg_rule_to_chan_bw_flags(const struct ieee80211_regdomain *regd,
 					  const struct ieee80211_reg_rule *reg_rule,
 					  const struct ieee80211_channel *chan)
@@ -1209,6 +1229,13 @@  static void handle_channel(struct wiphy *wiphy,
 		return;
 	}
 
+	if (!reg_center_freq_of_valid(wiphy, chan)) {
+		pr_debug("Disabling freq %d MHz as it's out of OF limits\n",
+			 chan->center_freq);
+		chan->flags |= IEEE80211_CHAN_DISABLED;
+		return;
+	}
+
 	regd = reg_get_regdomain(wiphy);
 
 	power_rule = &reg_rule->power_rule;
@@ -1741,6 +1768,13 @@  static void handle_channel_custom(struct wiphy *wiphy,
 		return;
 	}
 
+	if (!reg_center_freq_of_valid(wiphy, chan)) {
+		pr_debug("Disabling freq %d MHz as it's out of OF limits\n",
+			 chan->center_freq);
+		chan->flags |= IEEE80211_CHAN_DISABLED;
+		return;
+	}
+
 	power_rule = &reg_rule->power_rule;
 	bw_flags = reg_rule_to_chan_bw_flags(regd, reg_rule, chan);