[PATCH] net: stmmac: Fix the miscalculation of mapping from rxq to dma channel

[Shaokun Zhang]

From: yuqi jin <jiny...@huawei.com>

XGMAC_MTL_RXQ_DMA_MAP1 will be configured if the number of queues is
greater than 3, but local variable chan will shift left more than 32-bits.
Let's fix this issue.

Cc: Giuseppe Cavallaro <peppe.cavall...@st.com>
Cc: Alexandre Torgue <alexandre.tor...@st.com>
Cc: Jose Abreu <joab...@synopsys.com>
Cc: "David S. Miller" <da...@davemloft.net>
Cc: Maxime Coquelin <mcoquelin.st...@gmail.com>
Signed-off-by: Yuqi Jin <jiny...@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshao...@hisilicon.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c 
b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
index 0a32c96a7854..de4b15f31727 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
@@ -166,13 +166,14 @@ static void dwxgmac2_map_mtl_to_dma(struct 
mac_device_info *hw, u32 queue,
                                    u32 chan)
 {
        void __iomem *ioaddr = hw->pcsr;
-       u32 value, reg;
+       u32 value, reg, index;
 
        reg = (queue < 4) ? XGMAC_MTL_RXQ_DMA_MAP0 : XGMAC_MTL_RXQ_DMA_MAP1;
+       index = (queue < 4) ? queue : queue - 4;
 
        value = readl(ioaddr + reg);
-       value &= ~XGMAC_QxMDMACH(queue);
-       value |= (chan << XGMAC_QxMDMACH_SHIFT(queue)) & XGMAC_QxMDMACH(queue);
+       value &= ~XGMAC_QxMDMACH(index);
+       value |= (chan << XGMAC_QxMDMACH_SHIFT(index)) & XGMAC_QxMDMACH(index);
 
        writel(value, ioaddr + reg);
 }
-- 
2.7.4