diff mbox

ath9k: Support 4.9Ghz channels on AR9580 adapter.

Message ID 1466470940-25229-1-git-send-email-julian.calaby@gmail.com (mailing list archive)
State Rejected, archived
Delegated to: Kalle Valo
Headers show

Commit Message

Julian Calaby June 21, 2016, 1:02 a.m. UTC 
From: Ben Greear <greearb@candelatech.com>

NOTE:  These channels must not be used in most regulatory
domains unless you have a license from the FCC or similar!

A proper regulatory database is also required to actually use
these channels.

Signed-off-by: Ben Greear <greearb@candelatech.com>
[Hide this support behind a Kconfig option]
Signed-off-by: Julian Calaby <julian.calaby@gmail.com>
---
 drivers/net/wireless/ath/ath9k/Kconfig       | 19 +++++++++++
 drivers/net/wireless/ath/ath9k/ath9k.h       |  2 +-
 drivers/net/wireless/ath/ath9k/common-init.c | 49 +++++++++++++++++++++++-----
 drivers/net/wireless/ath/ath9k/hw.h          |  4 +--
 4 files changed, 63 insertions(+), 11 deletions(-)

Hi Kalle,

I've only done this work as I hate to see people's efforts go to
waste and I feel that there's enough roadblocks in the way of
actually using this functionality that casual idiots won't be able
to.

I've tried to keep the code hidden by the Kconfig option as minimal
as possible, however the #ifdef in ath9k_49ghz_capable() is arguably
not required as returning true from that function still results in no
action if the option is not enabled.

This is compile tested only as I cannot test this for real as I lack
both the hardware and license required.

Thanks,

Julian Calaby

Comments

Jouni Malinen June 21, 2016, 9:41 a.m. UTC | #1 
On Tue, Jun 21, 2016 at 11:02:20AM +1000, Julian Calaby wrote:
> I've only done this work as I hate to see people's efforts go to
> waste and I feel that there's enough roadblocks in the way of
> actually using this functionality that casual idiots won't be able
> to.

Are these really ready to go to the upstream kernel in this state and
without the other changes that would be needed to operate correctly?
What is the use case for these and how have these been tested?

> This is compile tested only as I cannot test this for real as I lack
> both the hardware and license required.

I don't think this is sufficient when touching this type of area. I
would not apply these without proper testing and full set of
functionality being available. I see no point in ath9k defining
additional channels if all those new channels can cause is harm and not
correct functionality. This channel list addition looks like the easiest
part to handle compared to the other patches needed for 4.9 GHz and this
would be the last patch on my list to get accepted..


> diff --git a/drivers/net/wireless/ath/ath9k/common-init.c b/drivers/net/wireless/ath/ath9k/common-init.c
> +#ifdef ATH9K_49_GHZ_CHAN
> +	/* 4.9Ghz channels, public safety channels, license is required in US
> +	 * and most other regulatory domains!
> +	 */
> +	CHAN5G(4915, 38), /* Channel 183 */
> +	CHAN5G(4920, 39), /* Channel 184 */
> +	CHAN5G(4925, 40), /* Channel 185 */
> +	CHAN5G(4935, 41), /* Channel 187 */
> +	CHAN5G(4940, 42), /* Channel 188 */
> +	CHAN5G(4945, 43), /* Channel 189 */
> +	CHAN5G(4960, 44), /* Channel 192 */
> +	CHAN5G(4970, 45), /* Channel 194 */
> +	CHAN5G(4980, 46), /* Channel 196 */

Where are these channels defined and are these really correct
frequencies for them? Please note that many of the 4.9 GHz channels have
channel starting frequencies like 4.9375 GHz and 4.0025 GHz, i.e.,
fractional MHz.. While US public safety may not have all those cases,
even there are some 0.5 MHz cases. In addition, those channel numbers
sound more like some of the channels defined in Japan rather than US
public safety operating class. In addition, some of these channels seem
to be outside the US public safety range.

Is this trying to add 4.9 GHz channels in general for multiple different
use cases? And if so, what are those use cases? Or is this only for some
public safety cases? And if so, for which regulatory domains?

To be frank, I really don't see how this would be even close to a state
that should be accepted into the upstream tree.
Julian Calaby June 21, 2016, 10:16 a.m. UTC | #2 
Hi Jouni,

On Tue, Jun 21, 2016 at 7:41 PM, Jouni Malinen <j@w1.fi> wrote:
> On Tue, Jun 21, 2016 at 11:02:20AM +1000, Julian Calaby wrote:
>> I've only done this work as I hate to see people's efforts go to
>> waste and I feel that there's enough roadblocks in the way of
>> actually using this functionality that casual idiots won't be able
>> to.
>
> Are these really ready to go to the upstream kernel in this state and
> without the other changes that would be needed to operate correctly?
> What is the use case for these and how have these been tested?

This patch is a edited version (adding the Kconfig option) of Ben's
patch. I picked it up as he seemed to have given up on it and I could
see nothing directly wrong with the patch.

>> This is compile tested only as I cannot test this for real as I lack
>> both the hardware and license required.
>
> I don't think this is sufficient when touching this type of area. I
> would not apply these without proper testing and full set of
> functionality being available. I see no point in ath9k defining
> additional channels if all those new channels can cause is harm and not
> correct functionality. This channel list addition looks like the easiest
> part to handle compared to the other patches needed for 4.9 GHz and this
> would be the last patch on my list to get accepted..

It isn't, Ben himself has said that fractional MHz need to be
supported for this to be 100% correct, however I believe that defining
the channels is minimally sufficient for his purposes. I do know he's
done more work than this, however I can't pick that up as getting it
ready for upstream requires testing I can't do.

>> diff --git a/drivers/net/wireless/ath/ath9k/common-init.c b/drivers/net/wireless/ath/ath9k/common-init.c
>> +#ifdef ATH9K_49_GHZ_CHAN
>> +     /* 4.9Ghz channels, public safety channels, license is required in US
>> +      * and most other regulatory domains!
>> +      */
>> +     CHAN5G(4915, 38), /* Channel 183 */
>> +     CHAN5G(4920, 39), /* Channel 184 */
>> +     CHAN5G(4925, 40), /* Channel 185 */
>> +     CHAN5G(4935, 41), /* Channel 187 */
>> +     CHAN5G(4940, 42), /* Channel 188 */
>> +     CHAN5G(4945, 43), /* Channel 189 */
>> +     CHAN5G(4960, 44), /* Channel 192 */
>> +     CHAN5G(4970, 45), /* Channel 194 */
>> +     CHAN5G(4980, 46), /* Channel 196 */
>
> Where are these channels defined and are these really correct
> frequencies for them? Please note that many of the 4.9 GHz channels have
> channel starting frequencies like 4.9375 GHz and 4.0025 GHz, i.e.,
> fractional MHz.. While US public safety may not have all those cases,
> even there are some 0.5 MHz cases. In addition, those channel numbers
> sound more like some of the channels defined in Japan rather than US
> public safety operating class. In addition, some of these channels seem
> to be outside the US public safety range.

From my perspective, this is enough to reject the patch outright. I
assumed the frequencies and numbers were correct, which is why I
picked it up.

> Is this trying to add 4.9 GHz channels in general for multiple different
> use cases? And if so, what are those use cases? Or is this only for some
> public safety cases? And if so, for which regulatory domains?

I believe he has a client that requires this support in a Linux kernel.

> To be frank, I really don't see how this would be even close to a state
> that should be accepted into the upstream tree.

Fair enough I'm dropping this.

Kalle, I've marked this as rejected and archived on Patchwork.

Thanks,
Ben Greear June 21, 2016, 2:17 p.m. UTC | #3 
On 06/21/2016 02:41 AM, Jouni Malinen wrote:
> On Tue, Jun 21, 2016 at 11:02:20AM +1000, Julian Calaby wrote:
>> I've only done this work as I hate to see people's efforts go to
>> waste and I feel that there's enough roadblocks in the way of
>> actually using this functionality that casual idiots won't be able
>> to.
>
> Are these really ready to go to the upstream kernel in this state and
> without the other changes that would be needed to operate correctly?
> What is the use case for these and how have these been tested?

More patches are needed to make this work properly.  My full patchset, with
modifications to supplicant, *has* been tested, including against a Cisco
AP running 5Mhz channels.


>> This is compile tested only as I cannot test this for real as I lack
>> both the hardware and license required.
>
> I don't think this is sufficient when touching this type of area. I
> would not apply these without proper testing and full set of
> functionality being available. I see no point in ath9k defining
> additional channels if all those new channels can cause is harm and not
> correct functionality. This channel list addition looks like the easiest
> part to handle compared to the other patches needed for 4.9 GHz and this
> would be the last patch on my list to get accepted..
>
>
>> diff --git a/drivers/net/wireless/ath/ath9k/common-init.c b/drivers/net/wireless/ath/ath9k/common-init.c
>> +#ifdef ATH9K_49_GHZ_CHAN
>> +	/* 4.9Ghz channels, public safety channels, license is required in US
>> +	 * and most other regulatory domains!
>> +	 */
>> +	CHAN5G(4915, 38), /* Channel 183 */
>> +	CHAN5G(4920, 39), /* Channel 184 */
>> +	CHAN5G(4925, 40), /* Channel 185 */
>> +	CHAN5G(4935, 41), /* Channel 187 */
>> +	CHAN5G(4940, 42), /* Channel 188 */
>> +	CHAN5G(4945, 43), /* Channel 189 */
>> +	CHAN5G(4960, 44), /* Channel 192 */
>> +	CHAN5G(4970, 45), /* Channel 194 */
>> +	CHAN5G(4980, 46), /* Channel 196 */
>
> Where are these channels defined and are these really correct
> frequencies for them? Please note that many of the 4.9 GHz channels have
> channel starting frequencies like 4.9375 GHz and 4.0025 GHz, i.e.,
> fractional MHz.. While US public safety may not have all those cases,
> even there are some 0.5 MHz cases. In addition, those channel numbers
> sound more like some of the channels defined in Japan rather than US
> public safety operating class. In addition, some of these channels seem
> to be outside the US public safety range.

I got these from WiKi pedia.  There is a later patch that adds the 5Mhz
channels that Cisco uses.  I figured that since this is all restricted anyway,
that users of it would know how to make it work (and they would have to hack
regdb in order to use any of them anyway).

> Is this trying to add 4.9 GHz channels in general for multiple different
> use cases? And if so, what are those use cases? Or is this only for some
> public safety cases? And if so, for which regulatory domains?
>
> To be frank, I really don't see how this would be even close to a state
> that should be accepted into the upstream tree.

It was a starting point, and posted mainly to let folks know how to get started.

As I said, I don't have interest in trying to push all the changes upstream,
but they are in my kernel tree on dmz2.candelatech.com and hostap tree on
github, so maybe someone who has interest in dealing with upstreaming them
can take them over.

Thanks,
Ben
Dave Taht June 21, 2016, 2:25 p.m. UTC | #4 
On Tue, Jun 21, 2016 at 2:41 AM, Jouni Malinen <j@w1.fi> wrote:
> On Tue, Jun 21, 2016 at 11:02:20AM +1000, Julian Calaby wrote:
>> I've only done this work as I hate to see people's efforts go to
>> waste and I feel that there's enough roadblocks in the way of
>> actually using this functionality that casual idiots won't be able
>> to.
>
> Are these really ready to go to the upstream kernel in this state and
> without the other changes that would be needed to operate correctly?
> What is the use case for these and how have these been tested?

So far as I know the use case for these is to make it possible to build
open source wifi systems that enable emergency services. This
strikes me as a worthy goal.
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diff mbox

Patch

diff --git a/drivers/net/wireless/ath/ath9k/Kconfig b/drivers/net/wireless/ath/ath9k/Kconfig
index f68cb00..57b0a41 100644
--- a/drivers/net/wireless/ath/ath9k/Kconfig
+++ b/drivers/net/wireless/ath/ath9k/Kconfig
@@ -114,6 +114,25 @@  config ATH9K_DFS_CERTIFIED
 	  developed. At this point enabling this option won't do anything
 	  except increase code size.
 
+config ATH9K_49_GHZ_CHAN
+	bool "Support 4.9Ghz public safety channels on some devices"
+	depends on ATH9K && CFG80211_CERTIFICATION_ONUS
+	default n
+	---help---
+	  This option enables support for 4.9 GHz channels on AR9580.
+
+	  These are PUBLIC SAFETY CHANNELS and MUST NOT BE USED in most
+	  regulatory domains UNLESS YOU HAVE A FULL LICENSE for their use from
+	  your local radio regulator, e.g. the FCC or equivalent. Using these
+	  channels without proper authorisation may result in serious legal
+	  consequences.
+
+	  You will also have to build a regulatory database with these channels
+	  enabled to actually use them.
+
+	  If you are a distro kernel builder or have any doubt whatsoever about
+	  your legal ability to use these channels, say N.
+
 config ATH9K_DYNACK
 	bool "Atheros ath9k ACK timeout estimation algorithm (EXPERIMENTAL)"
 	depends on ATH9K
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 93b3793..d8744b5 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -954,7 +954,7 @@  struct ath_softc {
 	struct device *dev;
 
 	struct survey_info *cur_survey;
-	struct survey_info survey[ATH9K_NUM_CHANNELS];
+	struct survey_info survey[ATH9K_MAX_NUM_CHANNELS];
 
 	struct tasklet_struct intr_tq;
 	struct tasklet_struct bcon_tasklet;
diff --git a/drivers/net/wireless/ath/ath9k/common-init.c b/drivers/net/wireless/ath/ath9k/common-init.c
index 8b4f7fd..f6a495b 100644
--- a/drivers/net/wireless/ath/ath9k/common-init.c
+++ b/drivers/net/wireless/ath/ath9k/common-init.c
@@ -86,6 +86,24 @@  static const struct ieee80211_channel ath9k_5ghz_chantable[] = {
 	CHAN5G(5785, 35), /* Channel 157 */
 	CHAN5G(5805, 36), /* Channel 161 */
 	CHAN5G(5825, 37), /* Channel 165 */
+
+#ifdef ATH9K_49_GHZ_CHAN
+	/* 4.9Ghz channels, public safety channels, license is required in US
+	 * and most other regulatory domains!
+	 */
+	CHAN5G(4915, 38), /* Channel 183 */
+	CHAN5G(4920, 39), /* Channel 184 */
+	CHAN5G(4925, 40), /* Channel 185 */
+	CHAN5G(4935, 41), /* Channel 187 */
+	CHAN5G(4940, 42), /* Channel 188 */
+	CHAN5G(4945, 43), /* Channel 189 */
+	CHAN5G(4960, 44), /* Channel 192 */
+	CHAN5G(4970, 45), /* Channel 194 */
+	CHAN5G(4980, 46), /* Channel 196 */
+#define ATH9K_NUM_49GHZ_CHANNELS 9
+#else
+#define ATH9K_NUM_49GHZ_CHANNELS 0
+#endif
 };
 
 /* Atheros hardware rate code addition for short premble */
@@ -122,14 +140,31 @@  static struct ieee80211_rate ath9k_legacy_rates[] = {
 			 IEEE80211_RATE_SUPPORTS_10MHZ)),
 };
 
+static bool ath9k_49ghz_capable(struct ath_hw *ah)
+{
+#ifdef ATH9K_49_GHZ_CHAN
+	/* Seems AR9580 supports 4.9ghz, at least. */
+	switch (ah->hw_version.devid) {
+	case AR9300_DEVID_AR9580:
+		return true;
+	}
+#endif
+
+	return false;
+}
+
 int ath9k_cmn_init_channels_rates(struct ath_common *common)
 {
 	struct ath_hw *ah = (struct ath_hw *)common->ah;
 	void *channels;
+	int num_5ghz_chan = ARRAY_SIZE(ath9k_5ghz_chantable);
+
+	if (!ath9k_49ghz_capable(ah))
+		num_5ghz_chan -= ATH9K_NUM_49GHZ_CHANNELS;
 
 	BUILD_BUG_ON(ARRAY_SIZE(ath9k_2ghz_chantable) +
-		     ARRAY_SIZE(ath9k_5ghz_chantable) !=
-		     ATH9K_NUM_CHANNELS);
+		     ARRAY_SIZE(ath9k_5ghz_chantable) >
+		     ATH9K_MAX_NUM_CHANNELS);
 
 	if (ah->caps.hw_caps & ATH9K_HW_CAP_2GHZ) {
 		channels = devm_kzalloc(ah->dev,
@@ -149,17 +184,16 @@  int ath9k_cmn_init_channels_rates(struct ath_common *common)
 	}
 
 	if (ah->caps.hw_caps & ATH9K_HW_CAP_5GHZ) {
-		channels = devm_kzalloc(ah->dev,
-			sizeof(ath9k_5ghz_chantable), GFP_KERNEL);
+		int ch_sz = num_5ghz_chan * sizeof(ath9k_5ghz_chantable[0]);
+
+		channels = devm_kzalloc(ah->dev, ch_sz, GFP_KERNEL);
 		if (!channels)
 			return -ENOMEM;
 
-		memcpy(channels, ath9k_5ghz_chantable,
-		       sizeof(ath9k_5ghz_chantable));
+		memcpy(channels, ath9k_5ghz_chantable, ch_sz);
 		common->sbands[NL80211_BAND_5GHZ].channels = channels;
 		common->sbands[NL80211_BAND_5GHZ].band = NL80211_BAND_5GHZ;
-		common->sbands[NL80211_BAND_5GHZ].n_channels =
-			ARRAY_SIZE(ath9k_5ghz_chantable);
+		common->sbands[NL80211_BAND_5GHZ].n_channels = num_5ghz_chan;
 		common->sbands[NL80211_BAND_5GHZ].bitrates =
 			ath9k_legacy_rates + 4;
 		common->sbands[NL80211_BAND_5GHZ].n_bitrates =
diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
index 9cbca12..8115d86 100644
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -73,7 +73,7 @@ 
 
 #define ATH9K_RSSI_BAD			-128
 
-#define ATH9K_NUM_CHANNELS	38
+#define ATH9K_MAX_NUM_CHANNELS	47
 
 /* Register read/write primitives */
 #define REG_WRITE(_ah, _reg, _val) \
@@ -777,7 +777,7 @@  struct ath_hw {
 	struct ath9k_hw_version hw_version;
 	struct ath9k_ops_config config;
 	struct ath9k_hw_capabilities caps;
-	struct ath9k_channel channels[ATH9K_NUM_CHANNELS];
+	struct ath9k_channel channels[ATH9K_MAX_NUM_CHANNELS];
 	struct ath9k_channel *curchan;
 
 	union {