ath5k: use tracing for packet tx/rx dump

This adds a few tracepoints to ath5k driver transmit and
receive callbacks in order to record packet traffic.
We record the entire packet in the trace buffer so that
the data can be extracted with trace-cmd and external
plugins.

Compared to the previous debugging calls, this approach
removes an out-of-line function call from the tx and rx
paths in the compiled-in-but-disabled case, while
improving the ability to process the logged data.

A new option, CONFIG_ATH5K_TRACER, is added so that one
may disable the tracepoints completely.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Bruno Randolf <br1@einfach.org>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/Kconfig

@@ -40,6 +40,17 @@ config ATH5K_DEBUG
 
 	  modprobe ath5k debug=0x00000400
 
+config ATH5K_TRACER
+	bool "Atheros 5xxx tracer"
+	depends on ATH5K
+	depends on EVENT_TRACING
+	---help---
+	  Say Y here to enable tracepoints for the ath5k driver
+	  using the kernel tracing infrastructure.  Select this
+	  option if you are interested in debugging the driver.
+
+	  If unsure, say N.
+
 config ATH5K_AHB
 	bool "Atheros 5xxx AHB bus support"
 	depends on (ATHEROS_AR231X && !PCI)

drivers/net/wireless/ath/ath5k/base.c

@@ -61,6 +61,9 @@
 #include "debug.h"
 #include "ani.h"
 
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
 int ath5k_modparam_nohwcrypt;
 module_param_named(nohwcrypt, ath5k_modparam_nohwcrypt, bool, S_IRUGO);
 MODULE_PARM_DESC(nohwcrypt, "Disable hardware encryption.");
@@ -1379,7 +1382,7 @@ ath5k_receive_frame(struct ath5k_softc *sc, struct sk_buff *skb,
 	    sc->sbands[sc->curchan->band].bitrates[rxs->rate_idx].hw_value_short)
 		rxs->flag |= RX_FLAG_SHORTPRE;
 
-	ath5k_debug_dump_skb(sc, skb, "RX  ", 0);
+	trace_ath5k_rx(sc, skb);
 
 	ath5k_update_beacon_rssi(sc, skb, rs->rs_rssi);
 
@@ -1524,7 +1527,7 @@ ath5k_tx_queue(struct ieee80211_hw *hw, struct sk_buff *skb,
 	unsigned long flags;
 	int padsize;
 
-	ath5k_debug_dump_skb(sc, skb, "TX  ", 1);
+	trace_ath5k_tx(sc, skb, txq);
 
 	/*
 	 * The hardware expects the header padded to 4 byte boundaries.
@@ -1573,7 +1576,7 @@ ath5k_tx_queue(struct ieee80211_hw *hw, struct sk_buff *skb,
 
 static void
 ath5k_tx_frame_completed(struct ath5k_softc *sc, struct sk_buff *skb,
-			 struct ath5k_tx_status *ts)
+			 struct ath5k_txq *txq, struct ath5k_tx_status *ts)
 {
 	struct ieee80211_tx_info *info;
 	int i;
@@ -1625,6 +1628,7 @@ ath5k_tx_frame_completed(struct ath5k_softc *sc, struct sk_buff *skb,
 	else
 		sc->stats.antenna_tx[0]++; /* invalid */
 
+	trace_ath5k_tx_complete(sc, skb, txq, ts);
 	ieee80211_tx_status(sc->hw, skb);
 }
 
@@ -1661,7 +1665,7 @@ ath5k_tx_processq(struct ath5k_softc *sc, struct ath5k_txq *txq)
 
 			dma_unmap_single(sc->dev, bf->skbaddr, skb->len,
 					DMA_TO_DEVICE);
-			ath5k_tx_frame_completed(sc, skb, &ts);
+			ath5k_tx_frame_completed(sc, skb, txq, &ts);
 		}
 
 		/*
@@ -1803,8 +1807,6 @@ ath5k_beacon_update(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 		goto out;
 	}
 
-	ath5k_debug_dump_skb(sc, skb, "BC  ", 1);
-
 	ath5k_txbuf_free_skb(sc, avf->bbuf);
 	avf->bbuf->skb = skb;
 	ret = ath5k_beacon_setup(sc, avf->bbuf);
@@ -1899,6 +1901,8 @@ ath5k_beacon_send(struct ath5k_softc *sc)
 			sc->opmode == NL80211_IFTYPE_MESH_POINT)
 		ath5k_beacon_update(sc->hw, vif);
 
+	trace_ath5k_tx(sc, bf->skb, &sc->txqs[sc->bhalq]);
+
 	ath5k_hw_set_txdp(ah, sc->bhalq, bf->daddr);
 	ath5k_hw_start_tx_dma(ah, sc->bhalq);
 	ATH5K_DBG(sc, ATH5K_DEBUG_BEACON, "TXDP[%u] = %llx (%p)\n",

drivers/net/wireless/ath/ath5k/trace.h

@@ -0,0 +1,107 @@
+#if !defined(__TRACE_ATH5K_H) || defined(TRACE_HEADER_MULTI_READ)
+#define __TRACE_ATH5K_H
+
+#include <linux/tracepoint.h>
+#include "base.h"
+
+#ifndef CONFIG_ATH5K_TRACER
+#undef TRACE_EVENT
+#define TRACE_EVENT(name, proto, ...) \
+static inline void trace_ ## name(proto) {}
+#endif
+
+struct sk_buff;
+
+#define PRIV_ENTRY  __field(struct ath5k_softc *, priv)
+#define PRIV_ASSIGN __entry->priv = priv
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM ath5k
+
+TRACE_EVENT(ath5k_rx,
+	TP_PROTO(struct ath5k_softc *priv, struct sk_buff *skb),
+	TP_ARGS(priv, skb),
+	TP_STRUCT__entry(
+		PRIV_ENTRY
+		__field(unsigned long, skbaddr)
+		__dynamic_array(u8, frame, skb->len)
+	),
+	TP_fast_assign(
+		PRIV_ASSIGN;
+		__entry->skbaddr = (unsigned long) skb;
+		memcpy(__get_dynamic_array(frame), skb->data, skb->len);
+	),
+	TP_printk(
+		"[%p] RX skb=%lx", __entry->priv, __entry->skbaddr
+	)
+);
+
+TRACE_EVENT(ath5k_tx,
+	TP_PROTO(struct ath5k_softc *priv, struct sk_buff *skb,
+		 struct ath5k_txq *q),
+
+	TP_ARGS(priv, skb, q),
+
+	TP_STRUCT__entry(
+		PRIV_ENTRY
+		__field(unsigned long, skbaddr)
+		__field(u8, qnum)
+		__dynamic_array(u8, frame, skb->len)
+	),
+
+	TP_fast_assign(
+		PRIV_ASSIGN;
+		__entry->skbaddr = (unsigned long) skb;
+		__entry->qnum = (u8) q->qnum;
+		memcpy(__get_dynamic_array(frame), skb->data, skb->len);
+	),
+
+	TP_printk(
+		"[%p] TX skb=%lx q=%d", __entry->priv, __entry->skbaddr,
+		__entry->qnum
+	)
+);
+
+TRACE_EVENT(ath5k_tx_complete,
+	TP_PROTO(struct ath5k_softc *priv, struct sk_buff *skb,
+		 struct ath5k_txq *q, struct ath5k_tx_status *ts),
+
+	TP_ARGS(priv, skb, q, ts),
+
+	TP_STRUCT__entry(
+		PRIV_ENTRY
+		__field(unsigned long, skbaddr)
+		__field(u8, qnum)
+		__field(u8, ts_status)
+		__field(s8, ts_rssi)
+		__field(u8, ts_antenna)
+	),
+
+	TP_fast_assign(
+		PRIV_ASSIGN;
+		__entry->skbaddr = (unsigned long) skb;
+		__entry->qnum = (u8) q->qnum;
+		__entry->ts_status = ts->ts_status;
+		__entry->ts_rssi =  ts->ts_rssi;
+		__entry->ts_antenna = ts->ts_antenna;
+	),
+
+	TP_printk(
+		"[%p] TX end skb=%lx q=%d stat=%x rssi=%d ant=%x",
+		__entry->priv, __entry->skbaddr, __entry->qnum,
+		__entry->ts_status, __entry->ts_rssi, __entry->ts_antenna
+	)
+);
+
+#endif /* __TRACE_ATH5K_H */
+
+#ifdef CONFIG_ATH5K_TRACER
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH ../../drivers/net/wireless/ath/ath5k
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+#include <trace/define_trace.h>
+
+#endif