bgmac: reset all cores on Northstar SoC

On the Northstar SoC (BCM4707 and BCM53018) we have to enable all GMAC
cores when we just want to use on. We iterate over all the cores and
activate them.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bgmac.c

@@ -1446,6 +1446,27 @@ static int bgmac_probe(struct bcma_device *core)
 
 	bgmac_chip_reset(bgmac);
 
+	/* For Northstar, we have to take all GMAC core out of reset */
+	if (core->id.id == BCMA_CHIP_ID_BCM4707 ||
+	    core->id.id == BCMA_CHIP_ID_BCM53018) {
+		struct bcma_device *ns_core;
+		int ns_gmac;
+
+		/* Northstar has 4 GMAC cores */
+		for (ns_gmac = 0; ns_gmac < 4; ns_gmac++) {
+			/* As northstar requirement, we have to reset all GAMCs
+			 * before accessing one. bgmac_chip_reset() call
+			 * bcma_core_enable() for this core. Then the other
+			 * three GAMCs didn't reset.  We do it here.
+			 */
+			ns_core = bcma_find_core_unit(core->bus,
+						      BCMA_CORE_MAC_GBIT,
+						      ns_gmac);
+			if (ns_core && !bcma_core_is_enabled(ns_core))
+				bcma_core_enable(ns_core, 0);
+		}
+	}
+
 	err = bgmac_dma_alloc(bgmac);
 	if (err) {
 		bgmac_err(bgmac, "Unable to alloc memory for DMA\n");