ARM: exynos: Fix infinite loops on CPU powerup failure

Add timeout to infinite loops during the CPU powerup procedures. It
is better to report an error instead of busylooping for infinite time
in case of failure.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

arch/arm/mach-exynos/mcpm-exynos.c

@@ -75,14 +75,25 @@ static int exynos_cpu_powerup(unsigned int cpu, unsigned int cluster)
 		 */
 		if (cluster &&
 		    cluster == MPIDR_AFFINITY_LEVEL(cpu_logical_map(0), 1)) {
+			unsigned int timeout = 16;
+
 			/*
 			 * Before we reset the Little cores, we should wait
 			 * the SPARE2 register is set to 1 because the init
 			 * codes of the iROM will set the register after
 			 * initialization.
 			 */
-			while (!pmu_raw_readl(S5P_PMU_SPARE2))
+			while (timeout && !pmu_raw_readl(S5P_PMU_SPARE2)) {
+				timeout--;
 				udelay(10);
+			}
+
+			if (timeout == 0) {
+				pr_err("cpu %u cluster %u powerup failed\n",
+				       cpu, cluster);
+				exynos_cpu_power_down(cpunr);
+				return -ETIMEDOUT;
+			}
 
 			pmu_raw_writel(EXYNOS5420_KFC_CORE_RESET(cpu),
 					EXYNOS_SWRESET);

arch/arm/mach-exynos/platsmp.c

@@ -214,13 +214,20 @@ static inline void __iomem *cpu_boot_reg(int cpu)
  */
 void exynos_core_restart(u32 core_id)
 {
+	unsigned int timeout = 16;
 	u32 val;
 
 	if (!of_machine_is_compatible("samsung,exynos3250"))
 		return;
 
-	while (!pmu_raw_readl(S5P_PMU_SPARE2))
+	while (timeout && !pmu_raw_readl(S5P_PMU_SPARE2)) {
+		timeout--;
 		udelay(10);
+	}
+	if (timeout == 0) {
+		pr_err("cpu core %u restart failed\n", core_id);
+		return;
+	}
 	udelay(10);
 
 	val = pmu_raw_readl(EXYNOS_ARM_CORE_STATUS(core_id));