ath: add common ath_rxbuf_alloc() and make ath9k use it

Turns out ath5k and ath9k can share the same helper to
allocates RX skbs. We allocate skbs aligned to the cache line
size. This requirement seems to have come from AR5210; when
this was not done it seems sometimes we'd get bogus data. I'm
also told it may have been a performance enhancement
consideration. In the end I can't be sure we can remove this
on new hardware so just keep this and start sharing it through
ath.ko.

Make ath9k start using this, ath5k is next.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath.h b/drivers/net/wireless/ath/ath.h
new file mode 100644
index 000000000000..e284cd3ac6d4
--- /dev/null
+++ b/drivers/net/wireless/ath/ath.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2008-2009 Atheros Communications Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef ATH_H
+#define ATH_H
+
+#include <linux/skbuff.h>
+
+struct ath_common {
+	u16 cachelsz;
+};
+
+struct sk_buff *ath_rxbuf_alloc(struct ath_common *common,
+				u32 len,
+				gfp_t gfp_mask);
+
+#endif /* ATH_H */