net: airoha: Add missing cleanup bits in airoha_qdma_cleanup_rx_queue()

In order to properly cleanup hw rx QDMA queues and bring the device to
the initial state, reset rx DMA queue head/tail index. Moreover, reset
queued DMA descriptor fields.

Fixes: 23020f0 ("net: airoha: Introduce ethernet support for EN7581 SoC")
Tested-by: Madhur Agrawal <[email protected]>
Signed-off-by: Lorenzo Bianconi <[email protected]>
Link: https://patch.msgid.link/20260327-airoha_qdma_cleanup_rx_queue-fix-v1-1-369d6ab1511a@kernel.org
Signed-off-by: Jakub Kicinski <[email protected]>

Author: LorenzoBianconi

drivers/net/ethernet/airoha/airoha_eth.c

@@ -794,18 +794,34 @@ static int airoha_qdma_init_rx_queue(struct airoha_queue *q,
 
 static void airoha_qdma_cleanup_rx_queue(struct airoha_queue *q)
 {
-	struct airoha_eth *eth = q->qdma->eth;
+	struct airoha_qdma *qdma = q->qdma;
+	struct airoha_eth *eth = qdma->eth;
+	int qid = q - &qdma->q_rx[0];
 
 	while (q->queued) {
 		struct airoha_queue_entry *e = &q->entry[q->tail];
+		struct airoha_qdma_desc *desc = &q->desc[q->tail];
 		struct page *page = virt_to_head_page(e->buf);
 
 		dma_sync_single_for_cpu(eth->dev, e->dma_addr, e->dma_len,
 					page_pool_get_dma_dir(q->page_pool));
 		page_pool_put_full_page(q->page_pool, page, false);
+		/* Reset DMA descriptor */
+		WRITE_ONCE(desc->ctrl, 0);
+		WRITE_ONCE(desc->addr, 0);
+		WRITE_ONCE(desc->data, 0);
+		WRITE_ONCE(desc->msg0, 0);
+		WRITE_ONCE(desc->msg1, 0);
+		WRITE_ONCE(desc->msg2, 0);
+		WRITE_ONCE(desc->msg3, 0);
+
 		q->tail = (q->tail + 1) % q->ndesc;
 		q->queued--;
 	}
+
+	q->head = q->tail;
+	airoha_qdma_rmw(qdma, REG_RX_DMA_IDX(qid), RX_RING_DMA_IDX_MASK,
+			FIELD_PREP(RX_RING_DMA_IDX_MASK, q->tail));
 }
 
 static int airoha_qdma_init_rx(struct airoha_qdma *qdma)