QS_HCT_CTRL
writeb(0, mmio_base + QS_HCT_CTRL); /* disable host interrupts */
writeb(1, mmio_base + QS_HCT_CTRL); /* enable host interrupts */
writeb(0, mmio_base + QS_HCT_CTRL); /* disable host interrupts */
writeb(0, mmio_base + QS_HCT_CTRL); /* disable host interrupts */
writeb(1, mmio_base + QS_HCT_CTRL); /* enable host interrupts */