p54: fix beaconing related firmware crash

This patch fixes a firmware crash which can be provoked by changing
operation mode.

Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Christian Lamparter <chunkeey@web.de>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 38 insertions, 20 deletions

diff --git a/drivers/net/wireless/p54/lmac.h b/drivers/net/wireless/p54/lmac.h
index af35cfcd4fe3..04b63ec80fa4 100644
--- a/drivers/net/wireless/p54/lmac.h
+++ b/drivers/net/wireless/p54/lmac.h
@@ -98,6 +98,10 @@ struct p54_hdr {
         (!((((struct p54_hdr *) ((struct sk_buff *) skb)->data)->       \
         flags) & cpu_to_le16(P54_HDR_FLAG_CONTROL)))
 
+#define GET_HW_QUEUE(skb)                                               \
+        (((struct p54_tx_data *)((struct p54_hdr *)                     \
+        skb->data)->data)->hw_queue)
+
 /*
  * shared interface ID definitions
  * The interface ID is a unique identification of a specific interface.
diff --git a/drivers/net/wireless/p54/main.c b/drivers/net/wireless/p54/main.c
index f19add2c3cac..955f6d7ec16a 100644
--- a/drivers/net/wireless/p54/main.c
+++ b/drivers/net/wireless/p54/main.c
@@ -130,7 +130,6 @@ static int p54_beacon_update(struct p54_common *priv,
                         struct ieee80211_vif *vif)
 {
         struct sk_buff *beacon;
-        __le32 old_beacon_req_id;
         int ret;
 
         beacon = ieee80211_beacon_get(priv->hw, vif);
@@ -140,15 +139,16 @@ static int p54_beacon_update(struct p54_common *priv,
         if (ret)
                 return ret;
 
-        old_beacon_req_id = priv->beacon_req_id;
-        priv->beacon_req_id = GET_REQ_ID(beacon);
-
-        ret = p54_tx_80211(priv->hw, beacon);
-        if (ret) {
-                priv->beacon_req_id = old_beacon_req_id;
-                return -ENOSPC;
-        }
-
+        /*
+         * During operation, the firmware takes care of beaconing.
+         * The driver only needs to upload a new beacon template, once
+         * the template was changed by the stack or userspace.
+         *
+         * LMAC API 3.2.2 also specifies that the driver does not need
+         * to cancel the old beacon template by hand, instead the firmware
+         * will release the previous one through the feedback mechanism.
+         */
+        WARN_ON(p54_tx_80211(priv->hw, beacon));
         priv->tsf_high32 = 0;
         priv->tsf_low32 = 0;
 
@@ -253,9 +253,14 @@ static void p54_remove_interface(struct ieee80211_hw *dev,
 
         mutex_lock(&priv->conf_mutex);
         priv->vif = NULL;
-        if (priv->beacon_req_id) {
+
+        /*
+         * LMAC API 3.2.2 states that any active beacon template must be
+         * canceled by the driver before attempting a mode transition.
+         */
+        if (le32_to_cpu(priv->beacon_req_id) != 0) {
                 p54_tx_cancel(priv, priv->beacon_req_id);
-                priv->beacon_req_id = cpu_to_le32(0);
+                wait_for_completion_interruptible_timeout(&priv->beacon_comp, HZ);
         }
         priv->mode = NL80211_IFTYPE_MONITOR;
         memset(priv->mac_addr, 0, ETH_ALEN);
@@ -544,6 +549,7 @@ struct ieee80211_hw *p54_init_common(size_t priv_data_len)
                                       BIT(NL80211_IFTYPE_MESH_POINT);
 
         dev->channel_change_time = 1000;        /* TODO: find actual value */
+        priv->beacon_req_id = cpu_to_le32(0);
         priv->tx_stats[P54_QUEUE_BEACON].limit = 1;
         priv->tx_stats[P54_QUEUE_FWSCAN].limit = 1;
         priv->tx_stats[P54_QUEUE_MGMT].limit = 3;
@@ -567,6 +573,7 @@ struct ieee80211_hw *p54_init_common(size_t priv_data_len)
         mutex_init(&priv->conf_mutex);
         mutex_init(&priv->eeprom_mutex);
         init_completion(&priv->eeprom_comp);
+        init_completion(&priv->beacon_comp);
         INIT_DELAYED_WORK(&priv->work, p54_work);
 
         return dev;
diff --git a/drivers/net/wireless/p54/p54.h b/drivers/net/wireless/p54/p54.h
index 584b1560aff0..1afc39410e85 100644
--- a/drivers/net/wireless/p54/p54.h
+++ b/drivers/net/wireless/p54/p54.h
@@ -211,6 +211,7 @@ struct p54_common {
         u16 aid;
         bool powersave_override;
         __le32 beacon_req_id;
+        struct completion beacon_comp;
 
         /* cryptographic engine information */
         u8 privacy_caps;
diff --git a/drivers/net/wireless/p54/txrx.c b/drivers/net/wireless/p54/txrx.c
index 416400c4ad03..0d589d68e547 100644
--- a/drivers/net/wireless/p54/txrx.c
+++ b/drivers/net/wireless/p54/txrx.c
@@ -134,9 +134,13 @@ static int p54_assign_address(struct p54_common *priv, struct sk_buff *skb)
         range = (void *) info->rate_driver_data;
         range->start_addr = target_addr;
         range->end_addr = target_addr + len;
+        data->req_id = cpu_to_le32(target_addr + priv->headroom);
+        if (IS_DATA_FRAME(skb) &&
+            unlikely(GET_HW_QUEUE(skb) == P54_QUEUE_BEACON))
+                priv->beacon_req_id = data->req_id;
+
         __skb_queue_after(&priv->tx_queue, target_skb, skb);
         spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
-        data->req_id = cpu_to_le32(target_addr + priv->headroom);
         return 0;
 }
 
@@ -209,13 +213,19 @@ static void p54_tx_qos_accounting_free(struct p54_common *priv,
                                        struct sk_buff *skb)
 {
         if (IS_DATA_FRAME(skb)) {
-                struct p54_hdr *hdr = (void *) skb->data;
-                struct p54_tx_data *data = (void *) hdr->data;
                 unsigned long flags;
 
                 spin_lock_irqsave(&priv->tx_stats_lock, flags);
-                priv->tx_stats[data->hw_queue].len--;
+                priv->tx_stats[GET_HW_QUEUE(skb)].len--;
                 spin_unlock_irqrestore(&priv->tx_stats_lock, flags);
+
+                if (unlikely(GET_HW_QUEUE(skb) == P54_QUEUE_BEACON)) {
+                        if (priv->beacon_req_id == GET_REQ_ID(skb)) {
+                                /* this is the  active beacon set anymore */
+                                priv->beacon_req_id = 0;
+                        }
+                        complete(&priv->beacon_comp);
+                }
         }
         p54_wake_queues(priv);
 }
@@ -403,10 +413,6 @@ static void p54_rx_frame_sent(struct p54_common *priv, struct sk_buff *skb)
          * and we don't want to confuse the mac80211 stack.
          */
         if (unlikely(entry_data->hw_queue < P54_QUEUE_FWSCAN)) {
-                if (entry_data->hw_queue == P54_QUEUE_BEACON &&
-                    hdr->req_id == priv->beacon_req_id)
-                        priv->beacon_req_id = cpu_to_le32(0);
-
                 dev_kfree_skb_any(entry);
                 return ;
         }