p54: implement flush callback

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

1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/net/wireless/p54/main.c b/drivers/net/wireless/p54/main.c
index 338e8dcac1f3..e14a05bbc485 100644
--- a/drivers/net/wireless/p54/main.c
+++ b/drivers/net/wireless/p54/main.c
@@ -524,6 +524,48 @@ static int p54_get_survey(struct ieee80211_hw *dev, int idx,
         return 0;
 }
 
+static unsigned int p54_flush_count(struct p54_common *priv)
+{
+        unsigned int total = 0, i;
+
+        BUILD_BUG_ON(P54_QUEUE_NUM > ARRAY_SIZE(priv->tx_stats));
+
+        /*
+         * Because the firmware has the sole control over any frames
+         * in the P54_QUEUE_BEACON or P54_QUEUE_SCAN queues, they
+         * don't really count as pending or active.
+         */
+        for (i = P54_QUEUE_MGMT; i < P54_QUEUE_NUM; i++)
+                total += priv->tx_stats[i].len;
+        return total;
+}
+
+static void p54_flush(struct ieee80211_hw *dev, bool drop)
+{
+        struct p54_common *priv = dev->priv;
+        unsigned int total, i;
+
+        /*
+         * Currently, it wouldn't really matter if we wait for one second
+         * or 15 minutes. But once someone gets around and completes the
+         * TODOs [ancel stuck frames / reset device] in p54_work, it will
+         * suddenly make sense to wait that long.
+         */
+        i = P54_STATISTICS_UPDATE * 2 / 20;
+
+        /*
+         * In this case no locking is required because as we speak the
+         * queues have already been stopped and no new frames can sneak
+         * up from behind.
+         */
+        while ((total = p54_flush_count(priv) && i--)) {
+                /* waste time */
+                msleep(20);
+        }
+
+        WARN(total, "tx flush timeout, unresponsive firmware");
+}
+
 static const struct ieee80211_ops p54_ops = {
         .tx                     = p54_tx_80211,
         .start                  = p54_start,
@@ -536,6 +578,7 @@ static const struct ieee80211_ops p54_ops = {
         .sta_remove             = p54_sta_add_remove,
         .set_key                = p54_set_key,
         .config                 = p54_config,
+        .flush                  = p54_flush,
         .bss_info_changed       = p54_bss_info_changed,
         .configure_filter       = p54_configure_filter,
         .conf_tx                = p54_conf_tx,