brcmsmac: Introduce AMPDU sessions for assembling AMPDUs

AMPDU session allows MPDUs to be temporarily queued until either a full
AMPDU has been collected or circumstances dictate that transmission
should start with a partial AMPDU. Packets are added to the session by
calling brcms_c_ampdu_add_frame(). brcms_c_ampdu_finalize() should be
called to fix up the tx headers in the first and last packet before
adding the packets to the DMA ring. brmcs_c_sendampdu() is converted to
using AMPDU sessions.

This patch has no real value on it's own, but is needed in preparation
for elimination of the tx packet queue from brcmsmac.
Signed-off-by: NSeth Forshee <seth.forshee@canonical.com>
Reviewed-by: NPieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: NArend van Spriel <arend@broadcom.com>
Tested-by: NDaniel Wagner <wagi@monom.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmsmac/ampdu.h

@@ -17,6 +17,32 @@
 #ifndef _BRCM_AMPDU_H_
 #define _BRCM_AMPDU_H_
 
+/*
+ * Data structure representing an in-progress session for accumulating
+ * frames for AMPDU.
+ *
+ * wlc: pointer to common driver data
+ * skb_list: queue of skb's for AMPDU
+ * max_ampdu_len: maximum length for this AMPDU
+ * max_ampdu_frames: maximum number of frames for this AMPDU
+ * ampdu_len: total number of bytes accumulated for this AMPDU
+ * dma_len: DMA length of this AMPDU
+ */
+struct brcms_ampdu_session {
+	struct brcms_c_info *wlc;
+	struct sk_buff_head skb_list;
+	unsigned max_ampdu_len;
+	u16 max_ampdu_frames;
+	u16 ampdu_len;
+	u16 dma_len;
+};
+
+extern void brcms_c_ampdu_reset_session(struct brcms_ampdu_session *session,
+					struct brcms_c_info *wlc);
+extern int brcms_c_ampdu_add_frame(struct brcms_ampdu_session *session,
+				   struct sk_buff *p);
+extern void brcms_c_ampdu_finalize(struct brcms_ampdu_session *session);
+
 extern struct ampdu_info *brcms_c_ampdu_attach(struct brcms_c_info *wlc);
 extern void brcms_c_ampdu_detach(struct ampdu_info *ampdu);
 extern int brcms_c_sendampdu(struct ampdu_info *ampdu,