b43: Add TX statistics debugging counters

This adds a few debugging counters, that are useful for debugging the
"card does not transmit" or "connection is unstable" kind of problems.
It's also useful for tuning an RC algorithm.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 80 insertions, 16 deletions

diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c
index 3b1f0e76b9a4..8e9497c526af 100644
--- a/drivers/net/wireless/b43/dma.c
+++ b/drivers/net/wireless/b43/dma.c
@@ -38,6 +38,7 @@
 #include <linux/delay.h>
 #include <linux/skbuff.h>
 #include <linux/etherdevice.h>
+#include <asm/div64.h>
 
 
 /* 32bit DMA ops. */
@@ -878,6 +879,17 @@ struct b43_dmaring *b43_setup_dmaring(struct b43_wldev *dev,
         goto out;
 }
 
+#define divide(a, b)    ({      \
+        typeof(a) __a = a;      \
+        do_div(__a, b);         \
+        __a;                    \
+  })
+
+#define modulo(a, b)    ({      \
+        typeof(a) __a = a;      \
+        do_div(__a, b);         \
+  })
+
 /* Main cleanup function. */
 static void b43_destroy_dmaring(struct b43_dmaring *ring,
                                 const char *ringname)
@@ -885,9 +897,34 @@ static void b43_destroy_dmaring(struct b43_dmaring *ring,
         if (!ring)
                 return;
 
-        b43dbg(ring->dev->wl, "DMA-%u %s max used slots: %d/%d\n",
-               (unsigned int)(ring->type), ringname,
-               ring->max_used_slots, ring->nr_slots);
+#ifdef CONFIG_B43_DEBUG
+        {
+                /* Print some statistics. */
+                u64 failed_packets = ring->nr_failed_tx_packets;
+                u64 succeed_packets = ring->nr_succeed_tx_packets;
+                u64 nr_packets = failed_packets + succeed_packets;
+                u64 permille_failed = 0, average_tries = 0;
+
+                if (nr_packets)
+                        permille_failed = divide(failed_packets * 1000, nr_packets);
+                if (nr_packets)
+                        average_tries = divide(ring->nr_total_packet_tries * 100, nr_packets);
+
+                b43dbg(ring->dev->wl, "DMA-%u %s: "
+                       "Used slots %d/%d, Failed frames %llu/%llu = %llu.%01llu%%, "
+                       "Average tries %llu.%02llu\n",
+                       (unsigned int)(ring->type), ringname,
+                       ring->max_used_slots,
+                       ring->nr_slots,
+                       (unsigned long long)failed_packets,
+                       (unsigned long long)succeed_packets,
+                       (unsigned long long)divide(permille_failed, 10),
+                       (unsigned long long)modulo(permille_failed, 10),
+                       (unsigned long long)divide(average_tries, 100),
+                       (unsigned long long)modulo(average_tries, 100));
+        }
+#endif /* DEBUG */
+
         /* Device IRQs are disabled prior entering this function,
          * so no need to take care of concurrency with rx handler stuff.
          */
@@ -1270,6 +1307,38 @@ out_unlock:
         return err;
 }
 
+static void b43_fill_txstatus_report(struct b43_dmaring *ring,
+                                    struct ieee80211_tx_status *report,
+                                    const struct b43_txstatus *status)
+{
+        bool frame_failed = 0;
+
+        if (status->acked) {
+                /* The frame was ACKed. */
+                report->flags |= IEEE80211_TX_STATUS_ACK;
+        } else {
+                /* The frame was not ACKed... */
+                if (!(report->control.flags & IEEE80211_TXCTL_NO_ACK)) {
+                        /* ...but we expected an ACK. */
+                        frame_failed = 1;
+                        report->excessive_retries = 1;
+                }
+        }
+        if (status->frame_count == 0) {
+                /* The frame was not transmitted at all. */
+                report->retry_count = 0;
+        } else {
+                report->retry_count = status->frame_count - 1;
+#ifdef CONFIG_B43_DEBUG
+                if (frame_failed)
+                        ring->nr_failed_tx_packets++;
+                else
+                        ring->nr_succeed_tx_packets++;
+                ring->nr_total_packet_tries += status->frame_count;
+#endif /* DEBUG */
+        }
+}
+
 void b43_dma_handle_txstatus(struct b43_wldev *dev,
                              const struct b43_txstatus *status)
 {
@@ -1304,18 +1373,7 @@ void b43_dma_handle_txstatus(struct b43_wldev *dev,
                          * status of the transmission.
                          * Some fields of txstat are already filled in dma_tx().
                          */
-                        if (status->acked) {
-                                meta->txstat.flags |= IEEE80211_TX_STATUS_ACK;
-                        } else {
-                                if (!(meta->txstat.control.flags
-                                      & IEEE80211_TXCTL_NO_ACK))
-                                        meta->txstat.excessive_retries = 1;
-                        }
-                        if (status->frame_count == 0) {
-                                /* The frame was not transmitted at all. */
-                                meta->txstat.retry_count = 0;
-                        } else
-                                meta->txstat.retry_count = status->frame_count - 1;
+                        b43_fill_txstatus_report(ring, &(meta->txstat), status);
                         ieee80211_tx_status_irqsafe(dev->wl->hw, meta->skb,
                                                     &(meta->txstat));
                         /* skb is freed by ieee80211_tx_status_irqsafe() */
diff --git a/drivers/net/wireless/b43/dma.h b/drivers/net/wireless/b43/dma.h
index 9336286d97a7..ea27085dec0e 100644
--- a/drivers/net/wireless/b43/dma.h
+++ b/drivers/net/wireless/b43/dma.h
@@ -256,7 +256,13 @@ struct b43_dmaring {
         int max_used_slots;
         /* Last time we injected a ring overflow. */
         unsigned long last_injected_overflow;
-#endif                          /* CONFIG_B43_DEBUG */
+        /* Statistics: Number of successfully transmitted packets */
+        u64 nr_succeed_tx_packets;
+        /* Statistics: Number of failed TX packets */
+        u64 nr_failed_tx_packets;
+        /* Statistics: Total number of TX plus all retries. */
+        u64 nr_total_packet_tries;
+#endif /* CONFIG_B43_DEBUG */
 };
 
 static inline u32 b43_dma_read(struct b43_dmaring *ring, u16 offset)