ath5k: Implement mac80211 callback set_coverage_class

The callback sets slot time as specified in IEEE 802.11-2007 section
17.3.8.6 (for 20MHz channels only for now) and raises ACK and CTS
timeouts accordingly. The values are persistent, they are restored after
device reset.

Signed-off-by: Lukas Turek <8an@praha12.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath5k/pcu.c b/drivers/net/wireless/ath/ath5k/pcu.c
index b601ff9865f..aefe84f9c04 100644
--- a/drivers/net/wireless/ath/ath5k/pcu.c
+++ b/drivers/net/wireless/ath/ath5k/pcu.c
@@ -286,6 +286,42 @@ unsigned int ath5k_hw_get_clockrate(struct ath5k_hw *ah)
 }
 
 /**
+ * ath5k_hw_get_default_slottime - Get the default slot time for current mode
+ *
+ * @ah: The &struct ath5k_hw
+ */
+unsigned int ath5k_hw_get_default_slottime(struct ath5k_hw *ah)
+{
+	struct ieee80211_channel *channel = ah->ah_current_channel;
+
+	if (channel->hw_value & CHANNEL_TURBO)
+		return 6; /* both turbo modes */
+
+	if (channel->hw_value & CHANNEL_CCK)
+		return 20; /* 802.11b */
+
+	return 9; /* 802.11 a/g */
+}
+
+/**
+ * ath5k_hw_get_default_sifs - Get the default SIFS for current mode
+ *
+ * @ah: The &struct ath5k_hw
+ */
+unsigned int ath5k_hw_get_default_sifs(struct ath5k_hw *ah)
+{
+	struct ieee80211_channel *channel = ah->ah_current_channel;
+
+	if (channel->hw_value & CHANNEL_TURBO)
+		return 8; /* both turbo modes */
+
+	if (channel->hw_value & CHANNEL_5GHZ)
+		return 16; /* 802.11a */
+
+	return 10; /* 802.11 b/g */
+}
+
+/**
  * ath5k_hw_set_lladdr - Set station id
  *
  * @ah: The &struct ath5k_hw
@@ -1094,3 +1130,24 @@ int ath5k_hw_set_key_lladdr(struct ath5k_hw *ah, u16 entry, const u8 *mac)
 	return 0;
 }
 
+/**
+ * ath5k_hw_set_coverage_class - Set IEEE 802.11 coverage class
+ *
+ * @ah: The &struct ath5k_hw
+ * @coverage_class: IEEE 802.11 coverage class number
+ *
+ * Sets slot time, ACK timeout and CTS timeout for given coverage class.
+ */
+void ath5k_hw_set_coverage_class(struct ath5k_hw *ah, u8 coverage_class)
+{
+	/* As defined by IEEE 802.11-2007 17.3.8.6 */
+	int slot_time = ath5k_hw_get_default_slottime(ah) + 3 * coverage_class;
+	int ack_timeout = ath5k_hw_get_default_sifs(ah) + slot_time;
+	int cts_timeout = ack_timeout;
+
+	ath5k_hw_set_slot_time(ah, slot_time);
+	ath5k_hw_set_ack_timeout(ah, ack_timeout);
+	ath5k_hw_set_cts_timeout(ah, cts_timeout);
+
+	ah->ah_coverage_class = coverage_class;
+}