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.
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)
--
Rafał
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