net: stmmac: xgmac: Clear previous RX buffer size

When switching between buffer sizes we need to clear the previous value.

Fixes: d6ddfacd ("net: stmmac: Add DMA related callbacks for XGMAC2")
Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h

@@ -343,6 +343,8 @@
 #define XGMAC_DMA_CH_RX_CONTROL(x)	(0x00003108 + (0x80 * (x)))
 #define XGMAC_RxPBL			GENMASK(21, 16)
 #define XGMAC_RxPBL_SHIFT		16
+#define XGMAC_RBSZ			GENMASK(14, 1)
+#define XGMAC_RBSZ_SHIFT		1
 #define XGMAC_RXST			BIT(0)
 #define XGMAC_DMA_CH_TxDESC_HADDR(x)	(0x00003110 + (0x80 * (x)))
 #define XGMAC_DMA_CH_TxDESC_LADDR(x)	(0x00003114 + (0x80 * (x)))

drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c

@@ -482,7 +482,8 @@ static void dwxgmac2_set_bfsize(void __iomem *ioaddr, int bfsize, u32 chan)
 	u32 value;
 
 	value = readl(ioaddr + XGMAC_DMA_CH_RX_CONTROL(chan));
-	value |= bfsize << 1;
+	value &= ~XGMAC_RBSZ;
+	value |= bfsize << XGMAC_RBSZ_SHIFT;
 	writel(value, ioaddr + XGMAC_DMA_CH_RX_CONTROL(chan));
 }