rt2x00: Add support for L2 padding during TX/RX

Some hardware require L2 padding between header and payload
because both must be aligned to a 4-byte boundary. This hardware
also is easier during the RX path since we no longer need to
move the entire payload but rather only the header to remove
the padding (mac80211 only wants the payload to be 4-byte aligned).

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index 0be395528261..7c5cbb192a6c 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -103,6 +103,15 @@
 #define GET_DURATION_RES(__size, __rate)(((__size) * 8 * 10) % (__rate))
 
 /*
+ * Determine the alignment requirement,
+ * to make sure the 802.11 payload is padded to a 4-byte boundrary
+ * we must determine the address of the payload and calculate the
+ * amount of bytes needed to move the data.
+ */
+#define ALIGN_SIZE(__skb, __header) \
+        (  ((unsigned long)((__skb)->data + (__header))) & 3 )
+
+/*
  * Standard timing and size defines.
  * These values should follow the ieee80211 specifications.
  */
@@ -590,6 +599,7 @@ enum rt2x00_flags {
         DRIVER_REQUIRE_SCHEDULED,
         DRIVER_REQUIRE_DMA,
         DRIVER_REQUIRE_COPY_IV,
+        DRIVER_REQUIRE_L2PAD,
 
         /*
          * Driver features