wl12xx: schedule TX packets according to FW occupancy

When selecting packets for transmission, prefer the ACs that are least
occupied in the FW. When packets for multiple ACs are present in the FW,
it decides which to transmit according to WMM QoS parameters.

With these changes, lower priority ACs should not be starved when higher
priority traffic is present.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

1 files changed, 45 insertions, 23 deletions

diff --git a/drivers/net/wireless/wl12xx/tx.c b/drivers/net/wireless/wl12xx/tx.c
index 5c618c5ceda..e6e5f54b8e4 100644
--- a/drivers/net/wireless/wl12xx/tx.c
+++ b/drivers/net/wireless/wl12xx/tx.c
@@ -168,7 +168,7 @@ static int wl1271_tx_allocate(struct wl1271 *wl, struct sk_buff *skb, u32 extra,
 	u32 total_len = skb->len + sizeof(struct wl1271_tx_hw_descr) + extra;
 	u32 len;
 	u32 total_blocks;
-	int id, ret = -EBUSY;
+	int id, ret = -EBUSY, ac;
 	u32 spare_blocks;
 
 	if (unlikely(wl->quirks & WL12XX_QUIRK_USE_2_SPARE_BLOCKS))
@@ -206,7 +206,9 @@ static int wl1271_tx_allocate(struct wl1271 *wl, struct sk_buff *skb, u32 extra,
 		desc->id = id;
 
 		wl->tx_blocks_available -= total_blocks;
-		wl->tx_allocated_blocks += total_blocks;
+
+		ac = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
+		wl->tx_allocated_blocks[ac] += total_blocks;
 
 		if (wl->bss_type == BSS_TYPE_AP_BSS)
 			wl->links[hlid].allocated_blks += total_blocks;
@@ -453,21 +455,41 @@ void wl1271_handle_tx_low_watermark(struct wl1271 *wl)
 	}
 }
 
+static struct sk_buff_head *wl1271_select_queue(struct wl1271 *wl,
+						struct sk_buff_head *queues)
+{
+	int i, q = -1;
+	u32 min_blks = 0xffffffff;
+
+	/*
+	 * Find a non-empty ac where:
+	 * 1. There are packets to transmit
+	 * 2. The FW has the least allocated blocks
+	 */
+	for (i = 0; i < NUM_TX_QUEUES; i++)
+		if (!skb_queue_empty(&queues[i]) &&
+		    (wl->tx_allocated_blocks[i] < min_blks)) {
+			q = i;
+			min_blks = wl->tx_allocated_blocks[q];
+		}
+
+	if (q == -1)
+		return NULL;
+
+	return &queues[q];
+}
+
 static struct sk_buff *wl1271_sta_skb_dequeue(struct wl1271 *wl)
 {
 	struct sk_buff *skb = NULL;
 	unsigned long flags;
+	struct sk_buff_head *queue;
 
-	skb = skb_dequeue(&wl->tx_queue[CONF_TX_AC_VO]);
-	if (skb)
-		goto out;
-	skb = skb_dequeue(&wl->tx_queue[CONF_TX_AC_VI]);
-	if (skb)
+	queue = wl1271_select_queue(wl, wl->tx_queue);
+	if (!queue)
 		goto out;
-	skb = skb_dequeue(&wl->tx_queue[CONF_TX_AC_BE]);
-	if (skb)
-		goto out;
-	skb = skb_dequeue(&wl->tx_queue[CONF_TX_AC_BK]);
+
+	skb = skb_dequeue(queue);
 
 out:
 	if (skb) {
@@ -484,6 +506,7 @@ static struct sk_buff *wl1271_ap_skb_dequeue(struct wl1271 *wl)
 	struct sk_buff *skb = NULL;
 	unsigned long flags;
 	int i, h, start_hlid;
+	struct sk_buff_head *queue;
 
 	/* start from the link after the last one */
 	start_hlid = (wl->last_tx_hlid + 1) % AP_MAX_LINKS;
@@ -492,21 +515,20 @@ static struct sk_buff *wl1271_ap_skb_dequeue(struct wl1271 *wl)
 	for (i = 0; i < AP_MAX_LINKS; i++) {
 		h = (start_hlid + i) % AP_MAX_LINKS;
 
-		skb = skb_dequeue(&wl->links[h].tx_queue[CONF_TX_AC_VO]);
-		if (skb)
-			goto out;
-		skb = skb_dequeue(&wl->links[h].tx_queue[CONF_TX_AC_VI]);
-		if (skb)
-			goto out;
-		skb = skb_dequeue(&wl->links[h].tx_queue[CONF_TX_AC_BE]);
-		if (skb)
-			goto out;
-		skb = skb_dequeue(&wl->links[h].tx_queue[CONF_TX_AC_BK]);
+		/* only consider connected stations */
+		if (h >= WL1271_AP_STA_HLID_START &&
+		    !test_bit(h - WL1271_AP_STA_HLID_START, wl->ap_hlid_map))
+			continue;
+
+		queue = wl1271_select_queue(wl, wl->links[h].tx_queue);
+		if (!queue)
+			continue;
+
+		skb = skb_dequeue(queue);
 		if (skb)
-			goto out;
+			break;
 	}
 
-out:
 	if (skb) {
 		wl->last_tx_hlid = h;
 		spin_lock_irqsave(&wl->wl_lock, flags);