SDCRNG_CTL_REG
data = (in_le32(rng_regs + SDCRNG_CTL_REG)
out_le32(rng_regs + SDCRNG_CTL_REG, ctl);
out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR);
out_le32(rng_regs + SDCRNG_CTL_REG,
in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl);