PIO_CTRL
reg = advk_readl(pcie, PIO_CTRL);
advk_writel(pcie, reg, PIO_CTRL);
reg = advk_readl(pcie, PIO_CTRL);
advk_writel(pcie, reg, PIO_CTRL);
reg = advk_readl(pcie, PIO_CTRL);
advk_writel(pcie, reg, PIO_CTRL);