cfg80211: Add new wireless regulatory infrastructure

This adds the new wireless regulatory infrastructure. The
main motiviation behind this was to centralize regulatory
code as each driver was implementing their own regulatory solution,
and to replace the initial centralized code we have where:

* only 3 regulatory domains are supported: US, JP and EU
* regulatory domains can only be changed through module parameter
* all rules were built statically in the kernel

We now have support for regulatory domains for many countries
and regulatory domains are now queried through a userspace agent
through udev allowing distributions to update regulatory rules
without updating the kernel.

Each driver can regulatory_hint() a regulatory domain
based on either their EEPROM mapped regulatory domain value to a
respective ISO/IEC 3166-1 country code or pass an internally built
regulatory domain. We also add support to let the user set the
regulatory domain through userspace in case of faulty EEPROMs to
further help compliance.

Support for world roaming will be added soon for cards capable of
this.

For more information see:

http://wireless.kernel.org/en/developers/Regulatory/CRDA

For now we leave an option to enable the old module parameter,
ieee80211_regdom, and to build the 3 old regdomains statically
(US, JP and EU). This option is CONFIG_WIRELESS_OLD_REGULATORY.
These old static definitions and the module parameter is being
scheduled for removal for 2.6.29. Note that if you use this
you won't make use of a world regulatory domain as its pointless.
If you leave this option enabled and if CRDA is present and you
use US or JP we will try to ask CRDA to update us a regulatory
domain for us.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 120 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 0a72d1e3d3a..9f40c4d417d 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -287,6 +287,66 @@ struct bss_parameters {
 	int use_short_slot_time;
 };
 
+/**
+ * enum reg_set_by - Indicates who is trying to set the regulatory domain
+ * @REGDOM_SET_BY_INIT: regulatory domain was set by initialization. We will be
+ * 	using a static world regulatory domain by default.
+ * @REGDOM_SET_BY_CORE: Core queried CRDA for a dynamic world regulatory domain.
+ * @REGDOM_SET_BY_USER: User asked the wireless core to set the
+ * 	regulatory domain.
+ * @REGDOM_SET_BY_DRIVER: a wireless drivers has hinted to the wireless core
+ *	it thinks its knows the regulatory domain we should be in.
+ * @REGDOM_SET_BY_COUNTRY_IE: the wireless core has received an 802.11 country
+ *	information element with regulatory information it thinks we
+ *	should consider.
+ */
+enum reg_set_by {
+	REGDOM_SET_BY_INIT,
+	REGDOM_SET_BY_CORE,
+	REGDOM_SET_BY_USER,
+	REGDOM_SET_BY_DRIVER,
+	REGDOM_SET_BY_COUNTRY_IE,
+};
+
+struct ieee80211_freq_range {
+	u32 start_freq_khz;
+	u32 end_freq_khz;
+	u32 max_bandwidth_khz;
+};
+
+struct ieee80211_power_rule {
+	u32 max_antenna_gain;
+	u32 max_eirp;
+};
+
+struct ieee80211_reg_rule {
+	struct ieee80211_freq_range freq_range;
+	struct ieee80211_power_rule power_rule;
+	u32 flags;
+};
+
+struct ieee80211_regdomain {
+	u32 n_reg_rules;
+	char alpha2[2];
+	struct ieee80211_reg_rule reg_rules[];
+};
+
+#define MHZ_TO_KHZ(freq) (freq * 1000)
+#define KHZ_TO_MHZ(freq) (freq / 1000)
+#define DBI_TO_MBI(gain) (gain * 100)
+#define MBI_TO_DBI(gain) (gain / 100)
+#define DBM_TO_MBM(gain) (gain * 100)
+#define MBM_TO_DBM(gain) (gain / 100)
+
+#define REG_RULE(start, end, bw, gain, eirp, reg_flags) { \
+	.freq_range.start_freq_khz = (start) * 1000, \
+	.freq_range.end_freq_khz = (end) * 1000, \
+	.freq_range.max_bandwidth_khz = (bw) * 1000, \
+	.power_rule.max_antenna_gain = (gain) * 100, \
+	.power_rule.max_eirp = (eirp) * 100, \
+	.flags = reg_flags, \
+	}
+
 /* from net/wireless.h */
 struct wiphy;
 
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index fb9e62211c3..f504e3eca7d 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -833,6 +833,8 @@ struct ieee80211_hw {
 	s8 max_signal;
 };
 
+struct ieee80211_hw *wiphy_to_hw(struct wiphy *wiphy);
+
 /**
  * SET_IEEE80211_DEV - set device for 802.11 hardware
  *
diff --git a/include/net/wireless.h b/include/net/wireless.h
index 1dc8ec3daa2..e4378cc6bf8 100644
--- a/include/net/wireless.h
+++ b/include/net/wireless.h
@@ -60,6 +60,7 @@ enum ieee80211_channel_flags {
  * with cfg80211.
  *
  * @center_freq: center frequency in MHz
+ * @max_bandwidth: maximum allowed bandwidth for this channel, in MHz
  * @hw_value: hardware-specific value for the channel
  * @flags: channel flags from &enum ieee80211_channel_flags.
  * @orig_flags: channel flags at registration time, used by regulatory
@@ -73,6 +74,7 @@ enum ieee80211_channel_flags {
 struct ieee80211_channel {
 	enum ieee80211_band band;
 	u16 center_freq;
+	u8 max_bandwidth;
 	u16 hw_value;
 	u32 flags;
 	int max_antenna_gain;
@@ -178,6 +180,7 @@ struct ieee80211_supported_band {
  * struct wiphy - wireless hardware description
  * @idx: the wiphy index assigned to this item
  * @class_dev: the class device representing /sys/class/ieee80211/<wiphy-name>
+ * @reg_notifier: the driver's regulatory notification callback
  */
 struct wiphy {
 	/* assign these fields before you register the wiphy */
@@ -197,6 +200,9 @@ struct wiphy {
 
 	struct ieee80211_supported_band *bands[IEEE80211_NUM_BANDS];
 
+	/* Lets us get back the wiphy on the callback */
+	int (*reg_notifier)(struct wiphy *wiphy, enum reg_set_by setby);
+
 	/* fields below are read-only, assigned by cfg80211 */
 
 	/* the item in /sys/class/ieee80211/ points to this,
@@ -322,6 +328,58 @@ extern int ieee80211_frequency_to_channel(int freq);
  */
 extern struct ieee80211_channel *__ieee80211_get_channel(struct wiphy *wiphy,
 							 int freq);
+/**
+ * __regulatory_hint - hint to the wireless core a regulatory domain
+ * @wiphy: if a driver is providing the hint this is the driver's very
+ * 	own &struct wiphy
+ * @alpha2: the ISO/IEC 3166 alpha2 being claimed the regulatory domain
+ * 	should be in. If @rd is set this should be NULL
+ * @rd: a complete regulatory domain, if passed the caller need not worry
+ * 	about freeing it
+ *
+ * The Wireless subsystem can use this function to hint to the wireless core
+ * what it believes should be the current regulatory domain by
+ * giving it an ISO/IEC 3166 alpha2 country code it knows its regulatory
+ * domain should be in or by providing a completely build regulatory domain.
+ *
+ * Returns -EALREADY if *a regulatory domain* has already been set. Note that
+ * this could be by another driver. It is safe for drivers to continue if
+ * -EALREADY is returned, if drivers are not capable of world roaming they
+ * should not register more channels than they support. Right now we only
+ * support listening to the first driver hint. If the driver is capable
+ * of world roaming but wants to respect its own EEPROM mappings for
+ * specific regulatory domains it should register the @reg_notifier callback
+ * on the &struct wiphy. Returns 0 if the hint went through fine or through an
+ * intersection operation. Otherwise a standard error code is returned.
+ *
+ */
+extern int __regulatory_hint(struct wiphy *wiphy, enum reg_set_by set_by,
+		const char *alpha2, struct ieee80211_regdomain *rd);
+/**
+ * regulatory_hint - driver hint to the wireless core a regulatory domain
+ * @wiphy: the driver's very own &struct wiphy
+ * @alpha2: the ISO/IEC 3166 alpha2 the driver claims its regulatory domain
+ * 	should be in. If @rd is set this should be NULL. Note that if you
+ * 	set this to NULL you should still set rd->alpha2 to some accepted
+ * 	alpha2.
+ * @rd: a complete regulatory domain provided by the driver. If passed
+ * 	the driver does not need to worry about freeing it.
+ *
+ * Wireless drivers can use this function to hint to the wireless core
+ * what it believes should be the current regulatory domain by
+ * giving it an ISO/IEC 3166 alpha2 country code it knows its regulatory
+ * domain should be in or by providing a completely build regulatory domain.
+ * If the driver provides an ISO/IEC 3166 alpha2 userspace will be queried
+ * for a regulatory domain structure for the respective country. If
+ * a regulatory domain is build and passed you should set the alpha2
+ * if possible, otherwise set it to the special value of "99" which tells
+ * the wireless core it is unknown. If you pass a built regulatory domain
+ * and we return non zero you are in charge of kfree()'ing the structure.
+ *
+ * See __regulatory_hint() documentation for possible return values.
+ */
+extern int regulatory_hint(struct wiphy *wiphy,
+		const char *alpha2, struct ieee80211_regdomain *rd);
 
 /**
  * ieee80211_get_channel - get channel struct from wiphy for specified frequency