SDHCI_TEGRA_VENDOR_CLOCK_CTRL
reg = sdhci_readl(host, SDHCI_TEGRA_VENDOR_CLOCK_CTRL);
sdhci_writel(host, reg, SDHCI_TEGRA_VENDOR_CLOCK_CTRL);
clk_ctrl = sdhci_readl(host, SDHCI_TEGRA_VENDOR_CLOCK_CTRL);
sdhci_writel(host, clk_ctrl, SDHCI_TEGRA_VENDOR_CLOCK_CTRL);
val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_CLOCK_CTRL);