ath5k: enable combined michael mic in key cache

For mac revisions >= "Griffin," the hardware allows the mic tx and rx
authenticator keys to share the same cache line, whereas earlier
hardware can only store the rx.  Enable the combined mic on hardware
that supports it.

Changes to ath5k.h
Changes-licensed-under: 3-Clause-BSD

Changes to attach.c, pcu.c, reg.h
Changes-licensed-under: ISC

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath5k/ath5k.h b/drivers/net/wireless/ath5k/ath5k.h
index 5ee2dd1..13df119 100644
--- a/drivers/net/wireless/ath5k/ath5k.h
+++ b/drivers/net/wireless/ath5k/ath5k.h
@@ -1052,6 +1052,7 @@
 	bool			ah_calibration;
 	bool			ah_running;
 	bool			ah_single_chip;
+	bool			ah_combined_mic;
 	enum ath5k_rfgain	ah_rf_gain;
 
 	u32			ah_mac_srev;
diff --git a/drivers/net/wireless/ath5k/attach.c b/drivers/net/wireless/ath5k/attach.c
index 49d82d7..dea378f 100644
--- a/drivers/net/wireless/ath5k/attach.c
+++ b/drivers/net/wireless/ath5k/attach.c
@@ -317,6 +317,12 @@
 		goto err_free;
 	}
 
+	if (srev >= AR5K_SREV_AR2414) {
+		ah->ah_combined_mic = true;
+		AR5K_REG_ENABLE_BITS(ah, AR5K_MISC_MODE,
+			AR5K_MISC_MODE_COMBINED_MIC);
+	}
+
 	/* MAC address is cleared until add_interface */
 	ath5k_hw_set_lladdr(ah, mac);
 
diff --git a/drivers/net/wireless/ath5k/pcu.c b/drivers/net/wireless/ath5k/pcu.c
index ad7ea36..dabe422 100644
--- a/drivers/net/wireless/ath5k/pcu.c
+++ b/drivers/net/wireless/ath5k/pcu.c
@@ -1096,20 +1096,20 @@
 		/* Install rx/tx MIC */
 		rxmic = (__le32 *) &key->key[16];
 		txmic = (__le32 *) &key->key[24];
-#if 0
-		/* MISC_MODE register & 0x04 - for mac srev >= griffin */
-		key_v[0] = rxmic[0];
-		key_v[1] = (txmic[0] >> 16) & 0xffff;
-		key_v[2] = rxmic[1];
-		key_v[3] = txmic[0] & 0xffff;
-		key_v[4] = txmic[1];
-#else
-		key_v[0] = rxmic[0];
-		key_v[1] = 0;
-		key_v[2] = rxmic[1];
-		key_v[3] = 0;
-		key_v[4] = 0;
-#endif
+
+		if (ah->ah_combined_mic) {
+			key_v[0] = rxmic[0];
+			key_v[1] = (txmic[0] >> 16) & 0xffff;
+			key_v[2] = rxmic[1];
+			key_v[3] = txmic[0] & 0xffff;
+			key_v[4] = txmic[1];
+		} else {
+			key_v[0] = rxmic[0];
+			key_v[1] = 0;
+			key_v[2] = rxmic[1];
+			key_v[3] = 0;
+			key_v[4] = 0;
+		}
 		for (i = 0; i < ARRAY_SIZE(key_v); i++)
 			ath5k_hw_reg_write(ah, le32_to_cpu(key_v[i]),
 				AR5K_KEYTABLE_OFF(micentry, i));
diff --git a/drivers/net/wireless/ath5k/reg.h b/drivers/net/wireless/ath5k/reg.h
index 69755fc..91aaeaf 100644
--- a/drivers/net/wireless/ath5k/reg.h
+++ b/drivers/net/wireless/ath5k/reg.h
@@ -1729,6 +1729,7 @@
 #define	AR5K_MISC_MODE			0x8120			/* Register Address */
 #define	AR5K_MISC_MODE_FBSSID_MATCH	0x00000001	/* Force BSSID match */
 #define	AR5K_MISC_MODE_ACKSIFS_MEM	0x00000002	/* ACK SIFS memory (?) */
+#define	AR5K_MISC_MODE_COMBINED_MIC	0x00000004	/* use rx/tx MIC key */
 /* more bits */
 
 /*