[ath9k-devel] [PATCH v0 1/6] support for antenna configuration profiles

[Daniel Golle <dgolle@allnet.de>]

This introduces support for configuring an external antenna switch from
userspace using the nl80211 API.
Inspired by the previous discussion this is done by letting the user choose
from a set of pre-defined values (=profiles).

Supplying both, a profile name and a verbose description via platform-data
might be overkill. Maybe just a profile name is enough and have verbose
descriptions either in iw of libiwinfo?


Signed-off-by: Daniel Golle <dgolle@allnet.de>

--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -1109,6 +1109,12 @@ enum nl80211_commands {
  *	%NL80211_CMD_TDLS_MGMT. Otherwise %NL80211_CMD_TDLS_OPER should be
  *	used for asking the driver to perform a TDLS operation.
  *
+ * @NL80211_ATTR_WIPHY_EXTANT_SUPPORT: Flag indicating support for an external
+ *	antenna switch.
+ * @NL80211_ATTR_WIPHY_EXTANT_STATE: Currently selected antenna switch profile.
+ * @NL80211_ATTR_WIPHY_EXTANT_SUPP_PROFILES: Nested attribute containing names
+ *	and descriptions of the supported antenna switch configuration profiles.
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -1337,6 +1343,10 @@ enum nl80211_attrs {
 	NL80211_ATTR_TDLS_SUPPORT,
 	NL80211_ATTR_TDLS_EXTERNAL_SETUP,
 
+	NL80211_ATTR_WIPHY_EXTANT_SUPPORT,
+	NL80211_ATTR_WIPHY_EXTANT_STATE,
+	NL80211_ATTR_WIPHY_EXTANT_SUPP_PROFILES,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -1632,6 +1644,26 @@ enum nl80211_mpath_info {
 	NL80211_MPATH_INFO_MAX = __NL80211_MPATH_INFO_AFTER_LAST - 1
 };
 
+
+/**
+ * enum nl80211_easp_attr - external antenna switch configuration profiles
+ * @__NL80211_EASP_ATTR_INVALID: attribute number 0 is reserved
+ * @NL80211_EASP_ATTR_ID: unique identifier
+ * @NL80211_EASP_ATTR_NAME: human-readable name of the configuration profile
+ * @NL80211_EASP_ATTR_DESC: human-readable description of the configuration profile
+ * @NL80211_EASP_ATTR_MAX: highest profile attribute currently defined
+ * @__NL80211_EASP_ATTR_AFTER_LAST: internal use
+ */
+enum nl80211_easp_attr {
+	__NL80211_EASP_ATTR_INVALID,
+	NL80211_EASP_ATTR_ID,
+	NL80211_EASP_ATTR_NAME,
+	NL80211_EASP_ATTR_DESC,
+	/* keep last */
+	__NL80211_EASP_ATTR_AFTER_LAST,
+	NL80211_EASP_ATTR_MAX = __NL80211_EASP_ATTR_AFTER_LAST - 1
+};
+
 /**
  * enum nl80211_band_attr - band attributes
  * @__NL80211_BAND_ATTR_INVALID: attribute number 0 is reserved
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -197,6 +197,9 @@ static const struct nla_policy nl80211_p
 	[NL80211_ATTR_TDLS_OPERATION] = { .type = NLA_U8 },
 	[NL80211_ATTR_TDLS_SUPPORT] = { .type = NLA_FLAG },
 	[NL80211_ATTR_TDLS_EXTERNAL_SETUP] = { .type = NLA_FLAG },
+	[NL80211_ATTR_WIPHY_EXTANT_SUPPORT] = { .type = NLA_FLAG },
+	[NL80211_ATTR_WIPHY_EXTANT_STATE] = { .type = NLA_U32 },
+	[NL80211_ATTR_WIPHY_EXTANT_SUPP_PROFILES] = { .type = NLA_NESTED },
 };
 
 /* policy for the key attributes */
@@ -245,6 +248,17 @@ nl80211_match_policy[NL80211_SCHED_SCAN_
 						 .len = IEEE80211_MAX_SSID_LEN },
 };
 
+/* policy for external antenna switch configuration profiles */
+static const struct nla_policy
+nl80211_easp_policy[NL80211_EASP_ATTR_MAX + 1] = {
+	[NL80211_EASP_ATTR_ID] = { .type = NLA_U32 },
+	[NL80211_EASP_ATTR_NAME] = { .type = NLA_STRING,
+					.len = IEEE80211_MAX_DATA_LEN },
+	[NL80211_EASP_ATTR_DESC] = { .type = NLA_STRING,
+					.len = IEEE80211_MAX_DATA_LEN },
+};
+
+
 /* ifidx get helper */
 static int nl80211_get_ifidx(struct netlink_callback *cb)
 {
@@ -692,6 +706,7 @@ static int nl80211_send_wiphy(struct sk_
 	struct nlattr *nl_bands, *nl_band;
 	struct nlattr *nl_freqs, *nl_freq;
 	struct nlattr *nl_rates, *nl_rate;
+	struct nlattr *nl_easps, *nl_easp;
 	struct nlattr *nl_cmds;
 	enum ieee80211_band band;
 	struct ieee80211_channel *chan;
@@ -743,6 +758,8 @@ static int nl80211_send_wiphy(struct sk_
 		NLA_PUT_FLAG(msg, NL80211_ATTR_TDLS_SUPPORT);
 	if (dev->wiphy.flags & WIPHY_FLAG_TDLS_EXTERNAL_SETUP)
 		NLA_PUT_FLAG(msg, NL80211_ATTR_TDLS_EXTERNAL_SETUP);
+	if (dev->wiphy.flags & WIPHY_FLAG_HAS_EXTANT_SWITCH)
+		NLA_PUT_FLAG(msg, NL80211_ATTR_WIPHY_EXTANT_SUPPORT);
 
 	NLA_PUT(msg, NL80211_ATTR_CIPHER_SUITES,
 		sizeof(u32) * dev->wiphy.n_cipher_suites,
@@ -770,6 +787,36 @@ static int nl80211_send_wiphy(struct sk_
 		}
 	}
 
+/* currently selected external antenna switch configuration profile */
+	if ((dev->wiphy.flags & WIPHY_FLAG_HAS_EXTANT_SWITCH) && dev->ops->get_extant) {
+		u32 extant;
+		int res;
+		res = dev->ops->get_extant(&dev->wiphy, &extant);
+		if (!res) {
+			NLA_PUT_U32(msg, NL80211_ATTR_WIPHY_EXTANT_STATE, extant);
+		}
+	}
+
+/* available external antenna switch configuration profiles */
+	if (dev->wiphy.flags & WIPHY_FLAG_HAS_EXTANT_SWITCH) {
+		nl_easps = nla_nest_start(msg, NL80211_ATTR_WIPHY_EXTANT_SUPP_PROFILES);
+		for (i = 0; dev->wiphy.extant[i].id >= 0; i++) {
+			nl_easp = nla_nest_start(msg, i);
+			if (!nl_easp)
+				goto nla_put_failure;
+			NLA_PUT_U32(msg, NL80211_EASP_ATTR_ID,
+				dev->wiphy.extant[i].id);
+			NLA_PUT(msg, NL80211_EASP_ATTR_NAME,
+				strlen(dev->wiphy.extant[i].name),
+				dev->wiphy.extant[i].name);
+			NLA_PUT(msg, NL80211_EASP_ATTR_DESC,
+				strlen(dev->wiphy.extant[i].desc),
+				dev->wiphy.extant[i].desc);
+			nla_nest_end(msg, nl_easp);
+		}
+		nla_nest_end(msg, nl_easps);
+	}
+
 	if (nl80211_put_iftypes(msg, NL80211_ATTR_SUPPORTED_IFTYPES,
 				dev->wiphy.interface_modes))
 		goto nla_put_failure;
@@ -1335,6 +1382,17 @@ static int nl80211_set_wiphy(struct sk_b
 			goto bad_res;
 	}
 
+	if (info->attrs[NL80211_ATTR_WIPHY_EXTANT_STATE]) {
+		u32 extant;
+		if ((!rdev->ops->set_extant) ||
+			(!rdev->wiphy.extant)) {
+			result = -EOPNOTSUPP;
+			goto bad_res;
+		}
+		extant = nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_EXTANT_STATE]);
+		result = rdev->ops->set_extant(&rdev->wiphy, extant);
+	}
+
 	changed = 0;
 
 	if (info->attrs[NL80211_ATTR_WIPHY_RETRY_SHORT]) {
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1435,6 +1435,9 @@ struct cfg80211_gtk_rekey_data {
  *
  * @get_antenna: Get current antenna configuration from device (tx_ant, rx_ant).
  *
+ * @set_extant: Select the external antenna switch configuration profile.
+ * @get_extant: Get currently selected antenna switch profile.
+ *
  * @set_ringparam: Set tx and rx ring sizes.
  *
  * @get_ringparam: Get tx and rx ring current and maximum sizes.
@@ -1613,6 +1616,9 @@ struct cfg80211_ops {
 	int	(*set_antenna)(struct wiphy *wiphy, u32 tx_ant, u32 rx_ant);
 	int	(*get_antenna)(struct wiphy *wiphy, u32 *tx_ant, u32 *rx_ant);
 
+	int	(*set_extant)(struct wiphy *wiphy, u32 extant);
+	int	(*get_extant)(struct wiphy *wiphy, u32 *extant);
+
 	int	(*set_ringparam)(struct wiphy *wiphy, u32 tx, u32 rx);
 	void	(*get_ringparam)(struct wiphy *wiphy,
 				 u32 *tx, u32 *tx_max, u32 *rx, u32 *rx_max);
@@ -1688,6 +1694,8 @@ struct cfg80211_ops {
  *	teardown packets should be sent through the @NL80211_CMD_TDLS_MGMT
  *	command. When this flag is not set, @NL80211_CMD_TDLS_OPER should be
  *	used for asking the driver/firmware to perform a TDLS operation.
+ * @WIPHY_FLAG_HAS_EXTANT_SWITCH: The device got a configurable external antenna
+ *	switch.
  */
 enum wiphy_flags {
 	WIPHY_FLAG_CUSTOM_REGULATORY		= BIT(0),
@@ -1706,6 +1714,7 @@ enum wiphy_flags {
 	WIPHY_FLAG_AP_UAPSD			= BIT(14),
 	WIPHY_FLAG_SUPPORTS_TDLS		= BIT(15),
 	WIPHY_FLAG_TDLS_EXTERNAL_SETUP		= BIT(16),
+	WIPHY_FLAG_HAS_EXTANT_SWITCH		= BIT(17),
 };
 
 /**
@@ -1833,6 +1842,21 @@ struct wiphy_wowlan_support {
 };
 
 /**
+ * struct wiphy_extant_profile - User-parsable external antenna switch info
+ *
+ * This structure is used to provide the available switch configurations.
+ * @id: unique identifier of the profile
+ * @name: profile name (a short string)
+ * @description: user-parsable description of the profile
+ */
+struct wiphy_extant_profile {
+	int id;
+	char *name;
+	char *desc;
+};
+
+
+/**
  * struct wiphy - wireless hardware description
  * @reg_notifier: the driver's regulatory notification callback,
  *	note that if your driver uses wiphy_apply_custom_regulatory()
@@ -1912,6 +1936,8 @@ struct wiphy_wowlan_support {
  *	configured as RX antennas. Antenna configuration commands will be
  *	rejected unless this or @available_antennas_tx is set.
  *
+ * @extant: struct holding the available external antenna switch configurations.
+ *
  * @max_remain_on_channel_duration: Maximum time a remain-on-channel operation
  *	may request, if implemented.
  *
@@ -1972,6 +1998,8 @@ struct wiphy {
 	u32 available_antennas_tx;
 	u32 available_antennas_rx;
 
+	struct wiphy_extant_profile *extant;
+
 	/* If multiple wiphys are registered and you're handed e.g.
 	 * a regular netdev with assigned ieee80211_ptr, you won't
 	 * know whether it points to a wiphy your driver has registered