wl12xx: avoid premature elp entrance

The elp_work is being enqueued on wl1271_ps_elp_sleep, but doesn't get
cancelled on wl1271_ps_elp_wakeup. This might cause immediate entrance
to elp when the wl->mutex is being released, rather than using the delayed
enqueueing optimization.

Cancel elp_work on wakeup request, and add a new WL1271_FLAG_ELP_REQUESTED
flag to further synchronize the elp actions.

[Fixed a couple of typos in some comments -- Luca]

Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

2 files changed, 25 insertions, 6 deletions

diff --git a/drivers/net/wireless/wl12xx/ps.c b/drivers/net/wireless/wl12xx/ps.c
index b8deada5d02..b59b67711a1 100644
--- a/drivers/net/wireless/wl12xx/ps.c
+++ b/drivers/net/wireless/wl12xx/ps.c
@@ -43,6 +43,10 @@ void wl1271_elp_work(struct work_struct *work)
         if (unlikely(wl->state == WL1271_STATE_OFF))
                 goto out;
 
+        /* our work might have been already cancelled */
+        if (unlikely(!test_bit(WL1271_FLAG_ELP_REQUESTED, &wl->flags)))
+                goto out;
+
         if (test_bit(WL1271_FLAG_IN_ELP, &wl->flags) ||
             (!test_bit(WL1271_FLAG_PSM, &wl->flags) &&
              !test_bit(WL1271_FLAG_IDLE, &wl->flags)))
@@ -61,12 +65,16 @@ out:
 /* Routines to toggle sleep mode while in ELP */
 void wl1271_ps_elp_sleep(struct wl1271 *wl)
 {
-        if (test_bit(WL1271_FLAG_PSM, &wl->flags) ||
-            test_bit(WL1271_FLAG_IDLE, &wl->flags)) {
-                cancel_delayed_work(&wl->elp_work);
-                ieee80211_queue_delayed_work(wl->hw, &wl->elp_work,
-                                             msecs_to_jiffies(ELP_ENTRY_DELAY));
-        }
+        /* we shouldn't get consecutive sleep requests */
+        if (WARN_ON(test_and_set_bit(WL1271_FLAG_ELP_REQUESTED, &wl->flags)))
+                return;
+
+        if (!test_bit(WL1271_FLAG_PSM, &wl->flags) &&
+            !test_bit(WL1271_FLAG_IDLE, &wl->flags))
+                return;
+
+        ieee80211_queue_delayed_work(wl->hw, &wl->elp_work,
+                                     msecs_to_jiffies(ELP_ENTRY_DELAY));
 }
 
 int wl1271_ps_elp_wakeup(struct wl1271 *wl)
@@ -77,6 +85,16 @@ int wl1271_ps_elp_wakeup(struct wl1271 *wl)
         u32 start_time = jiffies;
         bool pending = false;
 
+        /*
+         * we might try to wake up even if we didn't go to sleep
+         * before (e.g. on boot)
+         */
+        if (!test_and_clear_bit(WL1271_FLAG_ELP_REQUESTED, &wl->flags))
+                return 0;
+
+        /* don't cancel_sync as it might contend for a mutex and deadlock */
+        cancel_delayed_work(&wl->elp_work);
+
         if (!test_bit(WL1271_FLAG_IN_ELP, &wl->flags))
                 return 0;
 
diff --git a/drivers/net/wireless/wl12xx/wl12xx.h b/drivers/net/wireless/wl12xx/wl12xx.h
index 7c521af58e7..f3de96212b9 100644
--- a/drivers/net/wireless/wl12xx/wl12xx.h
+++ b/drivers/net/wireless/wl12xx/wl12xx.h
@@ -345,6 +345,7 @@ enum wl12xx_flags {
         WL1271_FLAG_TX_QUEUE_STOPPED,
         WL1271_FLAG_TX_PENDING,
         WL1271_FLAG_IN_ELP,
+        WL1271_FLAG_ELP_REQUESTED,
         WL1271_FLAG_PSM,
         WL1271_FLAG_PSM_REQUESTED,
         WL1271_FLAG_IRQ_RUNNING,