net: stmmac: xgmac: Detect Hash Table size dinamically

Since commit b8ef7020 ("net: stmmac: add support for hash table size
128/256 in dwmac4"), we can detect the Hash Table dinamically.

Let's implement this feature in XGMAC cores and fix possible setups that
don't support the maximum size for Hash Table.
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

@@ -122,6 +122,7 @@
 #define XGMAC_HWFEAT_GMIISEL		BIT(1)
 #define XGMAC_HW_FEATURE1		0x00000120
 #define XGMAC_HWFEAT_L3L4FNUM		GENMASK(30, 27)
+#define XGMAC_HWFEAT_HASHTBLSZ		GENMASK(25, 24)
 #define XGMAC_HWFEAT_RSSEN		BIT(20)
 #define XGMAC_HWFEAT_TSOEN		BIT(18)
 #define XGMAC_HWFEAT_SPHEN		BIT(17)

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

@@ -380,6 +380,7 @@ static void dwxgmac2_get_hw_feature(void __iomem *ioaddr,
 	/* MAC HW feature 1 */
 	hw_cap = readl(ioaddr + XGMAC_HW_FEATURE1);
 	dma_cap->l3l4fnum = (hw_cap & XGMAC_HWFEAT_L3L4FNUM) >> 27;
+	dma_cap->hash_tb_sz = (hw_cap & XGMAC_HWFEAT_HASHTBLSZ) >> 24;
 	dma_cap->rssen = (hw_cap & XGMAC_HWFEAT_RSSEN) >> 20;
 	dma_cap->tsoen = (hw_cap & XGMAC_HWFEAT_TSOEN) >> 18;
 	dma_cap->sphen = (hw_cap & XGMAC_HWFEAT_SPHEN) >> 17;