wifi: wilc1000: add back-off algorithm to balance tx queue packets

Add an algorithm to backoff the Tx Task when low memory scenario is
triggered at firmware. During high data transfer from host, the firmware
runs out of VMM memory, which is used to hold the frames from the host.
So, adding the flow control delays the transmit from host side when
there is not enough space to accommodate frames in firmware side.

Signed-off-by: Prasurjya Rohan Saikia <[email protected]>
Acked-by: Ajay Singh <[email protected]>
Signed-off-by: Kalle Valo <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

1 files changed, 16 insertions, 4 deletions

diff --git a/drivers/net/wireless/microchip/wilc1000/netdev.c b/drivers/net/wireless/microchip/wilc1000/netdev.c
index e9f59de31b0b..91d71e0f7ef2 100644
--- a/drivers/net/wireless/microchip/wilc1000/netdev.c
+++ b/drivers/net/wireless/microchip/wilc1000/netdev.c
@@ -148,8 +148,8 @@ static int wilc_txq_task(void *vp)
 
 	complete(&wl->txq_thread_started);
 	while (1) {
-		wait_for_completion(&wl->txq_event);
-
+		if (wait_for_completion_interruptible(&wl->txq_event))
+			continue;
 		if (wl->close) {
 			complete(&wl->txq_thread_started);
 
@@ -166,12 +166,24 @@ static int wilc_txq_task(void *vp)
 				srcu_idx = srcu_read_lock(&wl->srcu);
 				list_for_each_entry_rcu(ifc, &wl->vif_list,
 							list) {
-					if (ifc->mac_opened && ifc->ndev)
+					if (ifc->mac_opened &&
+					    netif_queue_stopped(ifc->ndev))
 						netif_wake_queue(ifc->ndev);
 				}
 				srcu_read_unlock(&wl->srcu, srcu_idx);
 			}
-		} while (ret == WILC_VMM_ENTRY_FULL_RETRY && !wl->close);
+			if (ret != WILC_VMM_ENTRY_FULL_RETRY)
+				break;
+			/* Back off TX task from sending packets for some time.
+			 * msleep_interruptible will allow RX task to run and
+			 * free buffers. TX task will be in TASK_INTERRUPTIBLE
+			 * state which will put the thread back to CPU running
+			 * queue when it's signaled even if the timeout isn't
+			 * elapsed. This gives faster chance for reserved SK
+			 * buffers to be free.
+			 */
+			msleep_interruptible(TX_BACKOFF_WEIGHT_MS);
+		} while (!wl->close);
 	}
 	return 0;
 }