GBECONT
writel(readl(GBECONT) & ~GBECONT_RMII0, GBECONT);
writel(readl(GBECONT) & ~GBECONT_RMII1, GBECONT);
writel(readl(GBECONT) | GBECONT_RMII0, GBECONT);
writel(readl(GBECONT) | GBECONT_RMII1, GBECONT);