[PATCH V4 net 5/5] net: stmmac: re-init rx buffers when mac resume back

[Joakim Zhang <qiangqing.zhang@nxp.com>]

During suspend/resume stress test, we found descriptor write back by DMA
could exhibit unusual behavior, e.g.:
	003 [0xc4310030]: 0x0 0x40 0x0 0xb5010040

We can see that desc3 write back is 0xb5010040, it is still ownd by DMA,
so application would not recycle this buffer. It will trigger fatal bus
error when DMA try to use this descriptor again. To fix this issue, we
should re-init all rx buffers when mac resume back.

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 87 ++++++++++++++++++-
 1 file changed, 86 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 04ba77775e52..e8e9e5b8c62d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1379,6 +1379,91 @@ static void stmmac_free_tx_buffer(struct stmmac_priv *priv, u32 queue, int i)
 	}
 }
 
+/**
+ * stmmac_reinit_rx_buffers - reinit the RX descriptor buffer.
+ * @priv: driver private structure
+ * Description: this function is called to re-allocate a receive buffer, perform
+ * the DMA mapping and init the descriptor.
+ */
+static int stmmac_reinit_rx_buffers(struct stmmac_priv *priv)
+{
+	u32 rx_count = priv->plat->rx_queues_to_use;
+	u32 queue;
+	int i;
+
+	for (queue = 0; queue < rx_count; queue++) {
+		struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
+
+		for (i = 0; i < priv->dma_rx_size; i++) {
+			struct stmmac_rx_buffer *buf = &rx_q->buf_pool[i];
+
+			if (buf->page) {
+				page_pool_recycle_direct(rx_q->page_pool, buf->page);
+				buf->page = NULL;
+			}
+
+			if (priv->sph && buf->sec_page) {
+				page_pool_recycle_direct(rx_q->page_pool, buf->sec_page);
+				buf->sec_page = NULL;
+			}
+		}
+	}
+
+	for (queue = 0; queue < rx_count; queue++) {
+		struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
+
+		for (i = 0; i < priv->dma_rx_size; i++) {
+			struct stmmac_rx_buffer *buf = &rx_q->buf_pool[i];
+			struct dma_desc *p;
+
+			if (priv->extend_desc)
+				p = &((rx_q->dma_erx + i)->basic);
+			else
+				p = rx_q->dma_rx + i;
+
+			if (!buf->page) {
+				buf->page = page_pool_dev_alloc_pages(rx_q->page_pool);
+				if (!buf->page)
+					goto err_reinit_rx_buffers;
+
+				buf->addr = page_pool_get_dma_addr(buf->page);
+			}
+
+			if (priv->sph && !buf->sec_page) {
+				buf->sec_page = page_pool_dev_alloc_pages(rx_q->page_pool);
+				if (!buf->sec_page)
+					goto err_reinit_rx_buffers;
+
+				buf->sec_addr = page_pool_get_dma_addr(buf->sec_page);
+			}
+
+			stmmac_set_desc_addr(priv, p, buf->addr);
+			if (priv->sph)
+				stmmac_set_desc_sec_addr(priv, p, buf->sec_addr, true);
+			else
+				stmmac_set_desc_sec_addr(priv, p, buf->sec_addr, false);
+			if (priv->dma_buf_sz == BUF_SIZE_16KiB)
+				stmmac_init_desc3(priv, p);
+		}
+	}
+
+	return 0;
+
+err_reinit_rx_buffers:
+	while (queue >= 0) {
+		while (--i >= 0)
+			stmmac_free_rx_buffer(priv, queue, i);
+
+		if (queue == 0)
+			break;
+
+		i = priv->dma_rx_size;
+		queue--;
+	}
+
+	return -ENOMEM;
+}
+
 /**
  * init_dma_rx_desc_rings - init the RX descriptor rings
  * @dev: net device structure
@@ -5340,7 +5425,7 @@ int stmmac_resume(struct device *dev)
 	mutex_lock(&priv->lock);
 
 	stmmac_reset_queues_param(priv);
-
+	stmmac_reinit_rx_buffers(priv);
 	stmmac_free_tx_skbufs(priv);
 	stmmac_clear_descriptors(priv);
 
-- 
2.17.1