[PATCH net 2/2] net: ethernet: mediatek: fix inconsistency of port number carried in TXD

sean.wang
2017-04-11T07:13:06Z

Fix port inconsistency on TXD due to hardware BUG that would cause
different port number is carried on the same TXD between tx_map()
and tx_unmap() with the iperf test. It would cause confusing BQL
logic which leads to kernel panic when dual GMAC runs concurrently.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
---
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 14 +++++++++-----
drivers/net/ethernet/mediatek/mtk_eth_soc.h | 12 +++++++++---
2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 48ba617..502956c 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -648,6 +648,8 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,

WRITE_ONCE(itxd->txd1, mapped_addr);
itx_buf->flags |= MTK_TX_FLAGS_SINGLE0;
+ itx_buf->flags |= (!mac->id) ? BIT(MTK_TX_FLAGS_FPORT0) :
+ BIT(MTK_TX_FLAGS_FPORT1);
dma_unmap_addr_set(itx_buf, dma_addr0, mapped_addr);
dma_unmap_len_set(itx_buf, dma_len0, skb_headlen(skb));

@@ -689,6 +691,9 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
memset(tx_buf, 0, sizeof(*tx_buf));
tx_buf->skb = (struct sk_buff *)MTK_DMA_DUMMY_DESC;
tx_buf->flags |= MTK_TX_FLAGS_PAGE0;
+ tx_buf->flags |= (!mac->id) ? BIT(MTK_TX_FLAGS_FPORT0) :
+ BIT(MTK_TX_FLAGS_FPORT1);
+
dma_unmap_addr_set(tx_buf, dma_addr0, mapped_addr);
dma_unmap_len_set(tx_buf, dma_len0, frag_map_size);
frag_size -= frag_map_size;
@@ -1011,17 +1016,16 @@ static int mtk_poll_tx(struct mtk_eth *eth, int budget)

while ((cpu != dma) && budget) {
u32 next_cpu = desc->txd2;
- int mac;
+ int mac = 0;

desc = mtk_qdma_phys_to_virt(ring, desc->txd2);
if ((desc->txd3 & TX_DMA_OWNER_CPU) == 0)
break;

- mac = (desc->txd4 >> TX_DMA_FPORT_SHIFT) &
- TX_DMA_FPORT_MASK;
- mac--;
-
tx_buf = mtk_desc_to_tx_buf(ring, desc);
+ if (tx_buf->flags & BIT(MTK_TX_FLAGS_FPORT1))
+ mac = 1;
+
skb = tx_buf->skb;
if (!skb) {
condition = 1;
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index 996024d..7327b23 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -410,12 +410,18 @@ struct mtk_hw_stats {
struct u64_stats_sync syncp;
};

-/* PDMA descriptor can point at 1-2 segments. This enum allows us to track how
- * memory was allocated so that it can be freed properly
- */
enum mtk_tx_flags {
+ /* PDMA descriptor can point at 1-2 segments. This enum allows us to
+ * track how memory was allocated so that it can be freed properly.
+ */
MTK_TX_FLAGS_SINGLE0 = 0x01,
MTK_TX_FLAGS_PAGE0 = 0x02,
+
+ /* MTK_TX_FLAGS_FPORTx allows tracking which port the transmitted
+ * SKB out instead of looking up through hardware TX descriptor.
+ */
+ MTK_TX_FLAGS_FPORT1 = 0x03,
+ MTK_TX_FLAGS_FPORT0 = 0x04,
};

/* This enum allows us to identify how the clock is defined on the array of the
--
1.9.1