SIL_SYSCFG
tmp = readl(mmio_base + SIL_SYSCFG);
writel(tmp, mmio_base + SIL_SYSCFG);
readl(mmio_base + SIL_SYSCFG); /* flush */
tmp = readl(mmio_base + SIL_SYSCFG);
writel(tmp, mmio_base + SIL_SYSCFG);