iwlwifi: pcie: build an A-MSDU using TSO core

When the op_mode sends an skb whose payload is bigger than
MSS, PCIe will create an A-MSDU out of it. PCIe assumes
that the skb that is coming from the op_mode can fit in one
A-MSDU. It is the op_mode's responsibility to make sure
that this guarantee holds.

Additional headers need to be built for the subframes.
The TSO core code takes care of the IP / TCP headers and
the driver takes care of the 802.11 subframe headers.

These headers are stored on a per-cpu page that is re-used
for all the packets handled on that same CPU. Each skb
holds a reference to that page and releases the page when
it is reclaimed. When the page gets full, it is released
and a new one is allocated.

Since any SKB that doesn't go through the fast-xmit path
of mac80211 will be segmented, we can assume here that the
packet is not WEP / TKIP and has a proper SNAP header.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/intel/iwlwifi/iwl-devtrace-data.h

@@ -1,6 +1,7 @@
 /******************************************************************************
  *
  * Copyright(c) 2009 - 2014 Intel Corporation. All rights reserved.
+ * Copyright(c) 2015        Intel Deutschland GmbH
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of version 2 of the GNU General Public License as
@@ -51,6 +52,22 @@ TRACE_EVENT(iwlwifi_dev_tx_data,
 	TP_printk("[%s] TX frame data", __get_str(dev))
 );
 
+TRACE_EVENT(iwlwifi_dev_tx_tso_chunk,
+	TP_PROTO(const struct device *dev,
+		 u8 *data_src, size_t data_len),
+	TP_ARGS(dev, data_src, data_len),
+	TP_STRUCT__entry(
+		DEV_ENTRY
+
+		__dynamic_array(u8, data, data_len)
+	),
+	TP_fast_assign(
+		DEV_ASSIGN;
+		memcpy(__get_dynamic_array(data), data_src, data_len);
+	),
+	TP_printk("[%s] TX frame data", __get_str(dev))
+);
+
 TRACE_EVENT(iwlwifi_dev_rx_data,
 	TP_PROTO(const struct device *dev,
 		 const struct iwl_trans *trans,