p54: move statistic timer update routine into a workqueue

This patch moves a good chunk of code from the former statistic update
timer routine into a workqueue, which is kindly provided by mac80211.

Also as a nice side-effect we can lay the foundation for other
essential housekeeping features we want to do in the future.
e.g:
 - drain the (clogged) tx_queue.
 - initiate bursts.

Signed-off-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 68 insertions, 46 deletions

diff --git a/drivers/net/wireless/p54/p54.h b/drivers/net/wireless/p54/p54.h
index d2dbb9e15d97..23b80ef4d015 100644
--- a/drivers/net/wireless/p54/p54.h
+++ b/drivers/net/wireless/p54/p54.h
@@ -71,6 +71,7 @@ struct p54_edcf_queue_param {
 #define FW_LM20 0x4c4d3230
 
 struct p54_common {
+        struct ieee80211_hw *hw;
         u32 rx_start;
         u32 rx_end;
         struct sk_buff_head tx_queue;
@@ -106,9 +107,7 @@ struct p54_common {
         struct ieee80211_tx_queue_stats tx_stats[8];
         struct p54_edcf_queue_param qos_params[8];
         struct ieee80211_low_level_stats stats;
-        struct timer_list stats_timer;
-        struct completion stats_comp;
-        struct sk_buff *cached_stats;
+        struct delayed_work work;
         struct sk_buff *cached_beacon;
         int noise;
         void *eeprom;
diff --git a/drivers/net/wireless/p54/p54common.c b/drivers/net/wireless/p54/p54common.c
index a4e99b02af02..36310f881874 100644
--- a/drivers/net/wireless/p54/p54common.c
+++ b/drivers/net/wireless/p54/p54common.c
@@ -589,6 +589,9 @@ static int p54_rx_data(struct ieee80211_hw *dev, struct sk_buff *skb)
 
         ieee80211_rx_irqsafe(dev, skb, &rx_status);
 
+        queue_delayed_work(dev->workqueue, &priv->work,
+                           msecs_to_jiffies(P54_STATISTICS_UPDATE));
+
         return -1;
 }
 
@@ -652,6 +655,27 @@ void p54_free_skb(struct ieee80211_hw *dev, struct sk_buff *skb)
 }
 EXPORT_SYMBOL_GPL(p54_free_skb);
 
+static struct sk_buff *p54_find_tx_entry(struct ieee80211_hw *dev,
+                                           __le32 req_id)
+{
+        struct p54_common *priv = dev->priv;
+        struct sk_buff *entry = priv->tx_queue.next;
+        unsigned long flags;
+
+        spin_lock_irqsave(&priv->tx_queue.lock, flags);
+        while (entry != (struct sk_buff *)&priv->tx_queue) {
+                struct p54_hdr *hdr = (struct p54_hdr *) entry->data;
+
+                if (hdr->req_id == req_id) {
+                        spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
+                        return entry;
+                }
+                entry = entry->next;
+        }
+        spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
+        return NULL;
+}
+
 static void p54_rx_frame_sent(struct ieee80211_hw *dev, struct sk_buff *skb)
 {
         struct p54_common *priv = dev->priv;
@@ -775,8 +799,12 @@ static void p54_rx_stats(struct ieee80211_hw *dev, struct sk_buff *skb)
         struct p54_common *priv = dev->priv;
         struct p54_hdr *hdr = (struct p54_hdr *) skb->data;
         struct p54_statistics *stats = (struct p54_statistics *) hdr->data;
-        u32 tsf32 = le32_to_cpu(stats->tsf32);
+        u32 tsf32;
+
+        if (unlikely(priv->mode == NL80211_IFTYPE_UNSPECIFIED))
+                return ;
 
+        tsf32 = le32_to_cpu(stats->tsf32);
         if (tsf32 < priv->tsf_low32)
                 priv->tsf_high32++;
         priv->tsf_low32 = tsf32;
@@ -786,9 +814,8 @@ static void p54_rx_stats(struct ieee80211_hw *dev, struct sk_buff *skb)
         priv->stats.dot11FCSErrorCount = le32_to_cpu(stats->rx_bad_fcs);
 
         priv->noise = p54_rssi_to_dbm(dev, le32_to_cpu(stats->noise));
-        complete(&priv->stats_comp);
 
-        mod_timer(&priv->stats_timer, jiffies + 5 * HZ);
+        p54_free_skb(dev, p54_find_tx_entry(dev, hdr->req_id));
 }
 
 static void p54_rx_trap(struct ieee80211_hw *dev, struct sk_buff *skb)
@@ -897,6 +924,8 @@ static int p54_assign_address(struct ieee80211_hw *dev, struct sk_buff *skb,
                  * have a few spare slots for control frames left.
                  */
                 ieee80211_stop_queues(dev);
+                queue_delayed_work(dev->workqueue, &priv->work,
+                                   msecs_to_jiffies(P54_TX_TIMEOUT));
 
                 if (unlikely(left == 32)) {
                         /*
@@ -1354,6 +1383,10 @@ static int p54_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
         if (unlikely(p54_assign_address(dev, skb, hdr, skb->len + tim_len)))
                 goto err;
         priv->tx(dev, skb, 0);
+
+        queue_delayed_work(dev->workqueue, &priv->work,
+                           msecs_to_jiffies(P54_TX_FRAME_LIFETIME));
+
         return 0;
 
  err:
@@ -1579,20 +1612,6 @@ static int p54_set_edcf(struct ieee80211_hw *dev)
         return 0;
 }
 
-static int p54_init_stats(struct ieee80211_hw *dev)
-{
-        struct p54_common *priv = dev->priv;
-
-        priv->cached_stats = p54_alloc_skb(dev, P54_HDR_FLAG_CONTROL,
-                        sizeof(struct p54_hdr) + sizeof(struct p54_statistics),
-                        P54_CONTROL_TYPE_STAT_READBACK, GFP_KERNEL);
-        if (!priv->cached_stats)
-                        return -ENOMEM;
-
-        mod_timer(&priv->stats_timer, jiffies + HZ);
-        return 0;
-}
-
 static int p54_beacon_tim(struct sk_buff *skb)
 {
         /*
@@ -1686,9 +1705,6 @@ static int p54_start(struct ieee80211_hw *dev)
         err = p54_set_edcf(dev);
         if (err)
                 goto out;
-        err = p54_init_stats(dev);
-        if (err)
-                goto out;
 
         memset(priv->bssid, ~0, ETH_ALEN);
         priv->mode = NL80211_IFTYPE_MONITOR;
@@ -1698,6 +1714,8 @@ static int p54_start(struct ieee80211_hw *dev)
                 goto out;
         }
 
+        queue_delayed_work(dev->workqueue, &priv->work, 0);
+
 out:
         mutex_unlock(&priv->conf_mutex);
         return err;
@@ -1710,9 +1728,7 @@ static void p54_stop(struct ieee80211_hw *dev)
 
         mutex_lock(&priv->conf_mutex);
         priv->mode = NL80211_IFTYPE_UNSPECIFIED;
-        del_timer(&priv->stats_timer);
-        p54_free_skb(dev, priv->cached_stats);
-        priv->cached_stats = NULL;
+        cancel_delayed_work_sync(&priv->work);
         if (priv->cached_beacon)
                 p54_tx_cancel(dev, priv->cached_beacon);
 
@@ -1889,14 +1905,29 @@ static int p54_init_xbow_synth(struct ieee80211_hw *dev)
         return 0;
 }
 
-static void p54_statistics_timer(unsigned long data)
+static void p54_work(struct work_struct *work)
 {
-        struct ieee80211_hw *dev = (struct ieee80211_hw *) data;
-        struct p54_common *priv = dev->priv;
+        struct p54_common *priv = container_of(work, struct p54_common,
+                                               work.work);
+        struct ieee80211_hw *dev = priv->hw;
+        struct sk_buff *skb;
+
+        if (unlikely(priv->mode == NL80211_IFTYPE_UNSPECIFIED))
+                return ;
+
+        /*
+         * TODO: walk through tx_queue and do the following tasks
+         *      1. initiate bursts.
+         *      2. cancel stuck frames / reset the device if necessary.
+         */
 
-        BUG_ON(!priv->cached_stats);
+        skb = p54_alloc_skb(dev, P54_HDR_FLAG_CONTROL, sizeof(struct p54_hdr) +
+                            sizeof(struct p54_statistics),
+                            P54_CONTROL_TYPE_STAT_READBACK, GFP_KERNEL);
+        if (!skb)
+                return ;
 
-        priv->tx(dev, priv->cached_stats, 0);
+        priv->tx(dev, skb, 0);
 }
 
 static int p54_get_stats(struct ieee80211_hw *dev,
@@ -1904,17 +1935,7 @@ static int p54_get_stats(struct ieee80211_hw *dev,
 {
         struct p54_common *priv = dev->priv;
 
-        del_timer(&priv->stats_timer);
-        p54_statistics_timer((unsigned long)dev);
-
-        if (!wait_for_completion_interruptible_timeout(&priv->stats_comp, HZ)) {
-                printk(KERN_ERR "%s: device does not respond!\n",
-                        wiphy_name(dev->wiphy));
-                return -EBUSY;
-        }
-
         memcpy(stats, &priv->stats, sizeof(*stats));
-
         return 0;
 }
 
@@ -2072,6 +2093,7 @@ struct ieee80211_hw *p54_init_common(size_t priv_data_len)
                 return NULL;
 
         priv = dev->priv;
+        priv->hw = dev;
         priv->mode = NL80211_IFTYPE_UNSPECIFIED;
         priv->basic_rate_mask = 0x15f;
         skb_queue_head_init(&priv->tx_queue);
@@ -2107,9 +2129,7 @@ struct ieee80211_hw *p54_init_common(size_t priv_data_len)
 
         mutex_init(&priv->conf_mutex);
         init_completion(&priv->eeprom_comp);
-        init_completion(&priv->stats_comp);
-        setup_timer(&priv->stats_timer, p54_statistics_timer,
-                (unsigned long)dev);
+        INIT_DELAYED_WORK(&priv->work, p54_work);
 
         return dev;
 }
@@ -2118,8 +2138,6 @@ EXPORT_SYMBOL_GPL(p54_init_common);
 void p54_free_common(struct ieee80211_hw *dev)
 {
         struct p54_common *priv = dev->priv;
-        del_timer(&priv->stats_timer);
-        kfree_skb(priv->cached_stats);
         kfree(priv->iq_autocal);
         kfree(priv->output_limit);
         kfree(priv->curve_data);
diff --git a/drivers/net/wireless/p54/p54common.h b/drivers/net/wireless/p54/p54common.h
index 5a68fdae7730..06e1643cc295 100644
--- a/drivers/net/wireless/p54/p54common.h
+++ b/drivers/net/wireless/p54/p54common.h
@@ -355,6 +355,11 @@ struct p54_tx_data {
         u8 align[0];
 } __attribute__ ((packed));
 
+/* unit is ms */
+#define P54_TX_FRAME_LIFETIME 2000
+#define P54_TX_TIMEOUT 4000
+#define P54_STATISTICS_UPDATE 5000
+
 #define P54_FILTER_TYPE_NONE            0
 #define P54_FILTER_TYPE_STATION         BIT(0)
 #define P54_FILTER_TYPE_IBSS            BIT(1)