On Fri, 18 Mar 2016, fu.wei at linaro.org wrote:

+static u32 __init arch_timer_mem_cnttidr(struct acpi_gtdt_timer_block *gt_block)
+{
+	phys_addr_t cntctlbase_phy;
+	void __iomem *cntctlbase;
+	u32 cnttidr;
+
+	cntctlbase_phy = (phys_addr_t)gtdt_gt_cntctlbase(gt_block);
+	if (!cntctlbase_phy) {
+		pr_err("Can't find CNTCTLBase.\n");
+		return 0;
+	}
+
+	/*
+	 * According to ARMv8 Architecture Reference Manual(ARM),
+	 * the size of CNTCTLBase frame of memory-mapped timer
+	 * is SZ_4K(Offset 0x000 ? 0xFFF).
+	 */
+	cntctlbase = ioremap(cntctlbase_phy, SZ_4K);
+	if (!cntctlbase) {
+		pr_err("Can't map CNTCTLBase\n");
+		return 0;
+	}

Why are you continuing when you can't find a base address or the remap fails?

+	/*
+	 * Get Generic Timer Counter-timer Timer ID Register
+	 * for Virtual Timer Capability info
+	 */
+	cnttidr = arch_timer_mem_cnttidr(gt_block);

Thanks,

	tglx