net: stmmac: Populate missing callbacks in HWIF initialization

Some HW specific setups, like sun8i, do not populate all the necessary
callbacks, which is what HWIF helpers were expecting.

Fix this by always trying to get the generic helpers and populate them
if they were not previously populated by HW specific setup.

Signed-off-by: Jose Abreu <[e-mail]>
Fixes: 5f0456b43140 ("net: stmmac: Implement logic to automatically
select HW Interface")
Reported-by: Corentin Labbe <[e-mail]>
Tested-by: Corentin Labbe <[e-mail]>
Cc: Corentin Labbe <[e-mail]>
Cc: David S. Miller <[e-mail]>
Cc: Joao Pinto <[e-mail]>
Cc: Giuseppe Cavallaro <[e-mail]>
Cc: Alexandre Torgue <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

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

···
 	bool needs_gmac = priv->plat->has_gmac;
 	const struct stmmac_hwif_entry *entry;
 	struct mac_device_info *mac;
+	bool needs_setup = true;
 	int i, ret;
 	u32 id;
 
 	if (needs_gmac) {
 		id = stmmac_get_id(priv, GMAC_VERSION);
-	} else {
+	} else if (needs_gmac4) {
 		id = stmmac_get_id(priv, GMAC4_VERSION);
+	} else {
+		id = 0;
 	}
 
 	/* Save ID for later use */
···
 
 	/* Check for HW specific setup first */
 	if (priv->plat->setup) {
-		priv->hw = priv->plat->setup(priv);
-		if (!priv->hw)
-			return -ENOMEM;
-		return 0;
+		mac = priv->plat->setup(priv);
+		needs_setup = false;
+	} else {
+		mac = devm_kzalloc(priv->device, sizeof(*mac), GFP_KERNEL);
 	}
 
-	mac = devm_kzalloc(priv->device, sizeof(*mac), GFP_KERNEL);
 	if (!mac)
 		return -ENOMEM;
 
···
 			continue;
 		if (needs_gmac4 ^ entry->gmac4)
 			continue;
-		if (id < entry->min_id)
+		/* Use synopsys_id var because some setups can override this */
+		if (priv->synopsys_id < entry->min_id)
 			continue;
 
-		mac->desc = entry->desc;
-		mac->dma = entry->dma;
-		mac->mac = entry->mac;
-		mac->ptp = entry->hwtimestamp;
-		mac->mode = entry->mode;
-		mac->tc = entry->tc;
+		/* Only use generic HW helpers if needed */
+		mac->desc = mac->desc ? : entry->desc;
+		mac->dma = mac->dma ? : entry->dma;
+		mac->mac = mac->mac ? : entry->mac;
+		mac->ptp = mac->ptp ? : entry->hwtimestamp;
+		mac->mode = mac->mode ? : entry->mode;
+		mac->tc = mac->tc ? : entry->tc;
 
 		priv->hw = mac;
 		priv->ptpaddr = priv->ioaddr + entry->regs.ptp_off;
 		priv->mmcaddr = priv->ioaddr + entry->regs.mmc_off;
 
 		/* Entry found */
-		ret = entry->setup(priv);
-		if (ret)
-			return ret;
+		if (needs_setup) {
+			ret = entry->setup(priv);
+			if (ret)
+				return ret;
+		}
 
 		/* Run quirks, if needed */
 		if (entry->quirks) {