rt2x00: Optimize TX descriptor handling

HT and no-HT rt2x00 devices use a partly different TX descriptor.
Optimize the tx desciptor memory layout by putting the PLCP and HT
substructs into a union and introduce a new driver flag to decide which
TX desciptor format is used by the device.

This saves us the expensive PLCP calculation fOr HT devices and the HT
descriptor setup on no-HT devices.

Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 13 insertions, 10 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c
index eebb564ee4da..7816c1c39d6e 100644
--- a/drivers/net/wireless/rt2x00/rt2x00queue.c
+++ b/drivers/net/wireless/rt2x00/rt2x00queue.c
@@ -270,12 +270,12 @@ static void rt2x00queue_create_tx_descriptor_plcp(struct queue_entry *entry,
          * PLCP setup
          * Length calculation depends on OFDM/CCK rate.
          */
-        txdesc->signal = hwrate->plcp;
-        txdesc->service = 0x04;
+        txdesc->u.plcp.signal = hwrate->plcp;
+        txdesc->u.plcp.service = 0x04;
 
         if (hwrate->flags & DEV_RATE_OFDM) {
-                txdesc->length_high = (data_length >> 6) & 0x3f;
-                txdesc->length_low = data_length & 0x3f;
+                txdesc->u.plcp.length_high = (data_length >> 6) & 0x3f;
+                txdesc->u.plcp.length_low = data_length & 0x3f;
         } else {
                 /*
                  * Convert length to microseconds.
@@ -290,18 +290,18 @@ static void rt2x00queue_create_tx_descriptor_plcp(struct queue_entry *entry,
                          * Check if we need to set the Length Extension
                          */
                         if (hwrate->bitrate == 110 && residual <= 30)
-                                txdesc->service |= 0x80;
+                                txdesc->u.plcp.service |= 0x80;
                 }
 
-                txdesc->length_high = (duration >> 8) & 0xff;
-                txdesc->length_low = duration & 0xff;
+                txdesc->u.plcp.length_high = (duration >> 8) & 0xff;
+                txdesc->u.plcp.length_low = duration & 0xff;
 
                 /*
                  * When preamble is enabled we should set the
                  * preamble bit for the signal.
                  */
                 if (txrate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE)
-                        txdesc->signal |= 0x08;
+                        txdesc->u.plcp.signal |= 0x08;
         }
 }
 
@@ -397,9 +397,12 @@ static void rt2x00queue_create_tx_descriptor(struct queue_entry *entry,
          * Apply TX descriptor handling by components
          */
         rt2x00crypto_create_tx_descriptor(entry, txdesc);
-        rt2x00ht_create_tx_descriptor(entry, txdesc, hwrate);
         rt2x00queue_create_tx_descriptor_seq(entry, txdesc);
-        rt2x00queue_create_tx_descriptor_plcp(entry, txdesc, hwrate);
+
+        if (test_bit(DRIVER_REQUIRE_HT_TX_DESC, &rt2x00dev->flags))
+                rt2x00ht_create_tx_descriptor(entry, txdesc, hwrate);
+        else
+                rt2x00queue_create_tx_descriptor_plcp(entry, txdesc, hwrate);
 }
 
 static int rt2x00queue_write_tx_data(struct queue_entry *entry,