iwlagn: add support for waiting for notifications

In order to implement waiting for notifications,
add a structure that captures the information,
and a list of such structures that will be
traversed when a command is received from the
ucode.

Use sparse checking to make sure calls to the
prepare/wait/cancel functions are always nested
correctly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 115 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
index 3dee87e8f55d..29dcda0bde65 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
@@ -473,6 +473,11 @@ void iwlagn_rx_handler_setup(struct iwl_priv *priv)
         priv->rx_handlers[CALIBRATION_COMPLETE_NOTIFICATION] =
                                         iwlagn_rx_calib_complete;
         priv->rx_handlers[REPLY_TX] = iwlagn_rx_reply_tx;
+
+        /* set up notification wait support */
+        spin_lock_init(&priv->_agn.notif_wait_lock);
+        INIT_LIST_HEAD(&priv->_agn.notif_waits);
+        init_waitqueue_head(&priv->_agn.notif_waitq);
 }
 
 void iwlagn_setup_deferred_work(struct iwl_priv *priv)
@@ -2389,3 +2394,44 @@ int iwl_dump_fh(struct iwl_priv *priv, char **buf, bool display)
         }
         return 0;
 }
+
+/* notification wait support */
+void iwlagn_init_notification_wait(struct iwl_priv *priv,
+                                   struct iwl_notification_wait *wait_entry,
+                                   void (*fn)(struct iwl_priv *priv,
+                                              struct iwl_rx_packet *pkt),
+                                   u8 cmd)
+{
+        wait_entry->fn = fn;
+        wait_entry->cmd = cmd;
+        wait_entry->triggered = false;
+
+        spin_lock_bh(&priv->_agn.notif_wait_lock);
+        list_add(&wait_entry->list, &priv->_agn.notif_waits);
+        spin_unlock_bh(&priv->_agn.notif_wait_lock);
+}
+
+signed long iwlagn_wait_notification(struct iwl_priv *priv,
+                                     struct iwl_notification_wait *wait_entry,
+                                     unsigned long timeout)
+{
+        int ret;
+
+        ret = wait_event_timeout(priv->_agn.notif_waitq,
+                                 &wait_entry->triggered,
+                                 timeout);
+
+        spin_lock_bh(&priv->_agn.notif_wait_lock);
+        list_del(&wait_entry->list);
+        spin_unlock_bh(&priv->_agn.notif_wait_lock);
+
+        return ret;
+}
+
+void iwlagn_remove_notification(struct iwl_priv *priv,
+                                struct iwl_notification_wait *wait_entry)
+{
+        spin_lock_bh(&priv->_agn.notif_wait_lock);
+        list_del(&wait_entry->list);
+        spin_unlock_bh(&priv->_agn.notif_wait_lock);
+}
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 624f174f8664..97657d04aa68 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -910,6 +910,27 @@ static void iwl_rx_handle(struct iwl_priv *priv)
                         (pkt->hdr.cmd != STATISTICS_NOTIFICATION) &&
                         (pkt->hdr.cmd != REPLY_TX);
 
+                /*
+                 * Do the notification wait before RX handlers so
+                 * even if the RX handler consumes the RXB we have
+                 * access to it in the notification wait entry.
+                 */
+                if (!list_empty(&priv->_agn.notif_waits)) {
+                        struct iwl_notification_wait *w;
+
+                        spin_lock(&priv->_agn.notif_wait_lock);
+                        list_for_each_entry(w, &priv->_agn.notif_waits, list) {
+                                if (w->cmd == pkt->hdr.cmd) {
+                                        w->triggered = true;
+                                        if (w->fn)
+                                                w->fn(priv, pkt);
+                                }
+                        }
+                        spin_unlock(&priv->_agn.notif_wait_lock);
+
+                        wake_up_all(&priv->_agn.notif_waitq);
+                }
+
                 /* Based on type of command response or notification,
                  *   handle those that need handling via function in
                  *   rx_handlers table.  See iwl_setup_rx_handlers() */
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.h b/drivers/net/wireless/iwlwifi/iwl-agn.h
index c30dc4f7a619..74d72ff24d05 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.h
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.h
@@ -329,6 +329,21 @@ void iwl_eeprom_get_mac(const struct iwl_priv *priv, u8 *mac);
 int iwlcore_eeprom_acquire_semaphore(struct iwl_priv *priv);
 void iwlcore_eeprom_release_semaphore(struct iwl_priv *priv);
 
+/* notification wait support */
+void __acquires(wait_entry)
+iwlagn_init_notification_wait(struct iwl_priv *priv,
+                              struct iwl_notification_wait *wait_entry,
+                              void (*fn)(struct iwl_priv *priv,
+                                         struct iwl_rx_packet *pkt),
+                              u8 cmd);
+signed long __releases(wait_entry)
+iwlagn_wait_notification(struct iwl_priv *priv,
+                         struct iwl_notification_wait *wait_entry,
+                         unsigned long timeout);
+void __releases(wait_entry)
+iwlagn_remove_notification(struct iwl_priv *priv,
+                           struct iwl_notification_wait *wait_entry);
+
 /* mac80211 handlers (for 4965) */
 int iwlagn_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
 int iwlagn_mac_start(struct ieee80211_hw *hw);
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 8dda67850af4..2ec680bb8f6d 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -34,6 +34,7 @@
 
 #include <linux/pci.h> /* for struct pci_device_id */
 #include <linux/kernel.h>
+#include <linux/wait.h>
 #include <net/ieee80211_radiotap.h>
 
 #include "iwl-eeprom.h"
@@ -1139,6 +1140,33 @@ struct iwl_force_reset {
  */
 #define IWLAGN_EXT_BEACON_TIME_POS      22
 
+/**
+ * struct iwl_notification_wait - notification wait entry
+ * @list: list head for global list
+ * @fn: function called with the notification
+ * @cmd: command ID
+ *
+ * This structure is not used directly, to wait for a
+ * notification declare it on the stack, and call
+ * iwlagn_init_notification_wait() with appropriate
+ * parameters. Then do whatever will cause the ucode
+ * to notify the driver, and to wait for that then
+ * call iwlagn_wait_notification().
+ *
+ * Each notification is one-shot. If at some point we
+ * need to support multi-shot notifications (which
+ * can't be allocated on the stack) we need to modify
+ * the code for them.
+ */
+struct iwl_notification_wait {
+        struct list_head list;
+
+        void (*fn)(struct iwl_priv *priv, struct iwl_rx_packet *pkt);
+
+        u8 cmd;
+        bool triggered;
+};
+
 enum iwl_rxon_context_id {
         IWL_RXON_CTX_BSS,
         IWL_RXON_CTX_PAN,
@@ -1463,6 +1491,11 @@ struct iwl_priv {
                         struct iwl_bt_notif_statistics delta_statistics_bt;
                         struct iwl_bt_notif_statistics max_delta_bt;
 #endif
+
+                        /* notification wait support */
+                        struct list_head notif_waits;
+                        spinlock_t notif_wait_lock;
+                        wait_queue_head_t notif_waitq;
                 } _agn;
 #endif
         };