[Linux-stm32] [PATCH] net: stmmac: Fix the miscalculation of mapping from rxq to dma channel

[Shaokun Zhang]

From: yuqi jin <jinyuqi at 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.cavallaro at st.com>
Cc: Alexandre Torgue <alexandre.torgue at st.com>
Cc: Jose Abreu <joabreu at synopsys.com>
Cc: "David S. Miller" <davem at davemloft.net>
Cc: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
Signed-off-by: Yuqi Jin <jinyuqi at huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun at 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