ARM: EXYNOS: add exynos_get_boot_addr() helper

Add get_cpu_boot_addr() firmware operation and then
exynos_get_boot_addr() helper.

This is a preparation for adding coupled cpuidle support
for Exynos3250 SoC.

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>

arch/arm/mach-exynos/platsmp.c

@@ -272,6 +272,31 @@ fail:
 	return ret;
 }
 
+static int exynos_get_boot_addr(u32 core_id, unsigned long *boot_addr)
+{
+	int ret;
+
+	/*
+	 * Try to get boot address using firmware first
+	 * and fall back to boot register if it fails.
+	 */
+	ret = call_firmware_op(get_cpu_boot_addr, core_id, boot_addr);
+	if (ret && ret != -ENOSYS)
+		goto fail;
+	if (ret == -ENOSYS) {
+		void __iomem *boot_reg = cpu_boot_reg(core_id);
+
+		if (IS_ERR(boot_reg)) {
+			ret = PTR_ERR(boot_reg);
+			goto fail;
+		}
+		*boot_addr = __raw_readl(boot_reg);
+		ret = 0;
+	}
+fail:
+	return ret;
+}
+
 static int exynos_boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
 	unsigned long timeout;