mt76: dma: introduce mt76_dma_queue_reset routine

Introduce mt76_dma_queue_reset utility routine to reset a given hw
queue. This is a preliminary patch to introduce mt7921 chip reset
support.
Co-developed-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/dma.c

@@ -79,13 +79,38 @@ mt76_free_pending_txwi(struct mt76_dev *dev)
 	local_bh_enable();
 }
 
+static void
+mt76_dma_sync_idx(struct mt76_dev *dev, struct mt76_queue *q)
+{
+	writel(q->desc_dma, &q->regs->desc_base);
+	writel(q->ndesc, &q->regs->ring_size);
+	q->head = readl(&q->regs->dma_idx);
+	q->tail = q->head;
+}
+
+static void
+mt76_dma_queue_reset(struct mt76_dev *dev, struct mt76_queue *q)
+{
+	int i;
+
+	if (!q)
+		return;
+
+	/* clear descriptors */
+	for (i = 0; i < q->ndesc; i++)
+		q->desc[i].ctrl = cpu_to_le32(MT_DMA_CTL_DMA_DONE);
+
+	writel(0, &q->regs->cpu_idx);
+	writel(0, &q->regs->dma_idx);
+	mt76_dma_sync_idx(dev, q);
+}
+
 static int
 mt76_dma_alloc_queue(struct mt76_dev *dev, struct mt76_queue *q,
 		     int idx, int n_desc, int bufsize,
 		     u32 ring_base)
 {
 	int size;
-	int i;
 
 	spin_lock_init(&q->lock);
 	spin_lock_init(&q->cleanup_lock);
@@ -105,14 +130,7 @@ mt76_dma_alloc_queue(struct mt76_dev *dev, struct mt76_queue *q,
 	if (!q->entry)
 		return -ENOMEM;
 
-	/* clear descriptors */
-	for (i = 0; i < q->ndesc; i++)
-		q->desc[i].ctrl = cpu_to_le32(MT_DMA_CTL_DMA_DONE);
-
-	writel(q->desc_dma, &q->regs->desc_base);
-	writel(0, &q->regs->cpu_idx);
-	writel(0, &q->regs->dma_idx);
-	writel(q->ndesc, &q->regs->ring_size);
+	mt76_dma_queue_reset(dev, q);
 
 	return 0;
 }
@@ -201,15 +219,6 @@ mt76_dma_tx_cleanup_idx(struct mt76_dev *dev, struct mt76_queue *q, int idx,
 	memset(e, 0, sizeof(*e));
 }
 
-static void
-mt76_dma_sync_idx(struct mt76_dev *dev, struct mt76_queue *q)
-{
-	writel(q->desc_dma, &q->regs->desc_base);
-	writel(q->ndesc, &q->regs->ring_size);
-	q->head = readl(&q->regs->dma_idx);
-	q->tail = q->head;
-}
-
 static void
 mt76_dma_kick_queue(struct mt76_dev *dev, struct mt76_queue *q)
 {
@@ -642,6 +651,7 @@ mt76_dma_init(struct mt76_dev *dev)
 static const struct mt76_queue_ops mt76_dma_ops = {
 	.init = mt76_dma_init,
 	.alloc = mt76_dma_alloc_queue,
+	.reset_q = mt76_dma_queue_reset,
 	.tx_queue_skb_raw = mt76_dma_tx_queue_skb_raw,
 	.tx_queue_skb = mt76_dma_tx_queue_skb,
 	.tx_cleanup = mt76_dma_tx_cleanup,

drivers/net/wireless/mediatek/mt76/mt76.h

@@ -192,6 +192,8 @@ struct mt76_queue_ops {
 			   bool flush);
 
 	void (*kick)(struct mt76_dev *dev, struct mt76_queue *q);
+
+	void (*reset_q)(struct mt76_dev *dev, struct mt76_queue *q);
 };
 
 enum mt76_wcid_flags {
@@ -796,6 +798,7 @@ static inline u16 mt76_rev(struct mt76_dev *dev)
 #define mt76_queue_rx_reset(dev, ...)	(dev)->mt76.queue_ops->rx_reset(&((dev)->mt76), __VA_ARGS__)
 #define mt76_queue_tx_cleanup(dev, ...)        (dev)->mt76.queue_ops->tx_cleanup(&((dev)->mt76), __VA_ARGS__)
 #define mt76_queue_kick(dev, ...)	(dev)->mt76.queue_ops->kick(&((dev)->mt76), __VA_ARGS__)
+#define mt76_queue_reset(dev, ...)	(dev)->mt76.queue_ops->reset_q(&((dev)->mt76), __VA_ARGS__)
 
 #define mt76_for_each_q_rx(dev, i)	\
 	for (i = 0; i < ARRAY_SIZE((dev)->q_rx) && \