SDMMC_MC1R
mc1r = sdhci_readb(host, SDMMC_MC1R);
sdhci_writeb(host, mc1r, SDMMC_MC1R);
mc1r = readb(host->ioaddr + SDMMC_MC1R);
writeb(mc1r, host->ioaddr + SDMMC_MC1R);