INTEL_QEPMAX
*ceiling = intel_qep_readl(qep, INTEL_QEPMAX);
intel_qep_writel(qep, INTEL_QEPMAX, max);
qep->qepmax = intel_qep_readl(qep, INTEL_QEPMAX);
intel_qep_writel(qep, INTEL_QEPMAX, qep->qepmax);