mt76: dma: cache dma map address/len in struct mt76_queue_entry

Accessing them from uncached memory can be expensive, so it's cheaper to
cache them
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -49,6 +49,7 @@ mt76_dma_add_buf(struct mt76_dev *dev, struct mt76_queue *q,
 		 struct mt76_queue_buf *buf, int nbufs, u32 info,
 		 struct sk_buff *skb, void *txwi)
 {
+	struct mt76_queue_entry *entry;
 	struct mt76_desc *desc;
 	u32 ctrl;
 	int i, idx = -1;
@@ -61,16 +62,27 @@ mt76_dma_add_buf(struct mt76_dev *dev, struct mt76_queue *q,
 	for (i = 0; i < nbufs; i += 2, buf += 2) {
 		u32 buf0 = buf[0].addr, buf1 = 0;
 
+		idx = q->head;
+		q->head = (q->head + 1) % q->ndesc;
+
+		desc = &q->desc[idx];
+		entry = &q->entry[idx];
+
 		if (buf[0].skip_unmap)
-			q->entry[q->head].skip_buf0 = true;
-		q->entry[q->head].skip_buf1 = i == nbufs - 1;
+			entry->skip_buf0 = true;
+		entry->skip_buf1 = i == nbufs - 1;
+
+		entry->dma_addr[0] = buf[0].addr;
+		entry->dma_len[0] = buf[0].len;
 
 		ctrl = FIELD_PREP(MT_DMA_CTL_SD_LEN0, buf[0].len);
 		if (i < nbufs - 1) {
+			entry->dma_addr[1] = buf[1].addr;
+			entry->dma_len[1] = buf[1].len;
 			buf1 = buf[1].addr;
 			ctrl |= FIELD_PREP(MT_DMA_CTL_SD_LEN1, buf[1].len);
 			if (buf[1].skip_unmap)
-				q->entry[q->head].skip_buf1 = true;
+				entry->skip_buf1 = true;
 		}
 
 		if (i == nbufs - 1)
@@ -78,11 +90,6 @@ mt76_dma_add_buf(struct mt76_dev *dev, struct mt76_queue *q,
 		else if (i == nbufs - 2)
 			ctrl |= MT_DMA_CTL_LAST_SEC1;
 
-		idx = q->head;
-		q->head = (q->head + 1) % q->ndesc;
-
-		desc = &q->desc[idx];
-
 		WRITE_ONCE(desc->buf0, cpu_to_le32(buf0));
 		WRITE_ONCE(desc->buf1, cpu_to_le32(buf1));
 		WRITE_ONCE(desc->info, cpu_to_le32(info));
@@ -102,24 +109,14 @@ mt76_dma_tx_cleanup_idx(struct mt76_dev *dev, struct mt76_queue *q, int idx,
 			struct mt76_queue_entry *prev_e)
 {
 	struct mt76_queue_entry *e = &q->entry[idx];
-	__le32 __ctrl = READ_ONCE(q->desc[idx].ctrl);
-	u32 ctrl = le32_to_cpu(__ctrl);
-
-	if (!e->skip_buf0) {
-		__le32 addr = READ_ONCE(q->desc[idx].buf0);
-		u32 len = FIELD_GET(MT_DMA_CTL_SD_LEN0, ctrl);
 
-		dma_unmap_single(dev->dev, le32_to_cpu(addr), len,
+	if (!e->skip_buf0)
+		dma_unmap_single(dev->dev, e->dma_addr[0], e->dma_len[0],
 				 DMA_TO_DEVICE);
-	}
-
-	if (!e->skip_buf1) {
-		__le32 addr = READ_ONCE(q->desc[idx].buf1);
-		u32 len = FIELD_GET(MT_DMA_CTL_SD_LEN1, ctrl);
 
-		dma_unmap_single(dev->dev, le32_to_cpu(addr), len,
+	if (!e->skip_buf1)
+		dma_unmap_single(dev->dev, e->dma_addr[1], e->dma_len[1],
 				 DMA_TO_DEVICE);
-	}
 
 	if (e->txwi == DMA_DUMMY_DATA)
 		e->txwi = NULL;
@@ -207,7 +204,7 @@ mt76_dma_get_buf(struct mt76_dev *dev, struct mt76_queue *q, int idx,
 	void *buf = e->buf;
 	int buf_len = SKB_WITH_OVERHEAD(q->buf_size);
 
-	buf_addr = le32_to_cpu(READ_ONCE(desc->buf0));
+	buf_addr = e->dma_addr[0];
 	if (len) {
 		u32 ctl = le32_to_cpu(READ_ONCE(desc->ctrl));
 		*len = FIELD_GET(MT_DMA_CTL_SD_LEN0, ctl);

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

@@ -102,6 +102,8 @@ struct mt76_queue_entry {
 		struct urb *urb;
 		int buf_sz;
 	};
+	u32 dma_addr[2];
+	u16 dma_len[2];
 	u16 wcid;
 	bool skip_buf0:1;
 	bool skip_buf1:1;