[PATCH net-next 1/2] net: stmmac: Return early if invalid in loongson_dwmac_fix_reset()

[Tiezhu Yang]

If the DMA_BUS_MODE_SFT_RESET bit is 1 before software reset,
there is no need to do anything for this abnormal case, just
return -EINVAL immediately in loongson_dwmac_fix_reset().

Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
index e1591e6217d4..6d10077666c7 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
@@ -513,6 +513,9 @@ static int loongson_dwmac_fix_reset(void *priv, void __iomem *ioaddr)
 {
 	u32 value = readl(ioaddr + DMA_BUS_MODE);
 
+	if (value & DMA_BUS_MODE_SFT_RESET)
+		return -EINVAL;
+
 	value |= DMA_BUS_MODE_SFT_RESET;
 	writel(value, ioaddr + DMA_BUS_MODE);
 
-- 
2.42.0