iwlwifi: pcie: allow the op_mode to freeze the stuck queue timer
This allows the op_mode to let the transport know that a
queue is currently frozen and that its timer should be
stopped.
When the queue is unfrozen, its timer should be set to
expire after the remainder of the timeout has elapsed.
This can be used when stations go to sleep. When a station
goes to sleep, the op_mode can freeze the timer so that the
queue will never be considered as stuck. When the station
wakes up, the queue will be unfrozen.
This is meant to avoid false positives that would happen if
a buggy station goes to sleep for a very long time. In case
we have a dedicated queue for this station (BA agreement)
and it goes to sleep for a very long time, the queue would
rightfully be stopped during all that time. In this case,
the stuck queue timer could fire and that would be a false
positive.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/pcie/trans.c b/drivers/net/wireless/iwlwifi/pcie/trans.c
index 9ce5e61..dc24732 100644
--- a/drivers/net/wireless/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/iwlwifi/pcie/trans.c
@@ -1504,6 +1504,60 @@
return ret;
}
+static void iwl_trans_pcie_freeze_txq_timer(struct iwl_trans *trans,
+ unsigned long txqs,
+ bool freeze)
+{
+ struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
+ int queue;
+
+ for_each_set_bit(queue, &txqs, BITS_PER_LONG) {
+ struct iwl_txq *txq = &trans_pcie->txq[queue];
+ unsigned long now;
+
+ spin_lock_bh(&txq->lock);
+
+ now = jiffies;
+
+ if (txq->frozen == freeze)
+ goto next_queue;
+
+ IWL_DEBUG_TX_QUEUES(trans, "%s TXQ %d\n",
+ freeze ? "Freezing" : "Waking", queue);
+
+ txq->frozen = freeze;
+
+ if (txq->q.read_ptr == txq->q.write_ptr)
+ goto next_queue;
+
+ if (freeze) {
+ if (unlikely(time_after(now,
+ txq->stuck_timer.expires))) {
+ /*
+ * The timer should have fired, maybe it is
+ * spinning right now on the lock.
+ */
+ goto next_queue;
+ }
+ /* remember how long until the timer fires */
+ txq->frozen_expiry_remainder =
+ txq->stuck_timer.expires - now;
+ del_timer(&txq->stuck_timer);
+ goto next_queue;
+ }
+
+ /*
+ * Wake a non-empty queue -> arm timer with the
+ * remainder before it froze
+ */
+ mod_timer(&txq->stuck_timer,
+ now + txq->frozen_expiry_remainder);
+
+next_queue:
+ spin_unlock_bh(&txq->lock);
+ }
+}
+
#define IWL_FLUSH_WAIT_MS 2000
static int iwl_trans_pcie_wait_txq_empty(struct iwl_trans *trans, u32 txq_bm)
@@ -1755,7 +1809,7 @@
int ret;
size_t bufsz;
- bufsz = sizeof(char) * 64 * trans->cfg->base_params->num_of_queues;
+ bufsz = sizeof(char) * 75 * trans->cfg->base_params->num_of_queues;
if (!trans_pcie->txq)
return -EAGAIN;
@@ -1768,11 +1822,11 @@
txq = &trans_pcie->txq[cnt];
q = &txq->q;
pos += scnprintf(buf + pos, bufsz - pos,
- "hwq %.2d: read=%u write=%u use=%d stop=%d need_update=%d%s\n",
+ "hwq %.2d: read=%u write=%u use=%d stop=%d need_update=%d frozen=%d%s\n",
cnt, q->read_ptr, q->write_ptr,
!!test_bit(cnt, trans_pcie->queue_used),
!!test_bit(cnt, trans_pcie->queue_stopped),
- txq->need_update,
+ txq->need_update, txq->frozen,
(cnt == trans_pcie->cmd_queue ? " HCMD" : ""));
}
ret = simple_read_from_buffer(user_buf, count, ppos, buf, pos);
@@ -2348,6 +2402,7 @@
.dbgfs_register = iwl_trans_pcie_dbgfs_register,
.wait_tx_queue_empty = iwl_trans_pcie_wait_txq_empty,
+ .freeze_txq_timer = iwl_trans_pcie_freeze_txq_timer,
.write8 = iwl_trans_pcie_write8,
.write32 = iwl_trans_pcie_write32,