clocksource/drivers/arm_arch_timer: Convert init function to return error

The init functions do not return any error. They behave as the following:

  - panic, thus leading to a kernel crash while another timer may work and
       make the system boot up correctly

  or

  - print an error and let the caller unaware if the state of the system

Change that by converting the init functions to return an error conforming
to the CLOCKSOURCE_OF_RET prototype.

Proper error handling (rollback, errno value) will be changed later case
by case, thus this change just return back an error or success in the init
function.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/arm_arch_timer.c

@@ -693,25 +693,26 @@ arch_timer_needs_probing(int type, const struct of_device_id *matches)
 	return needs_probing;
 }
 
-static void __init arch_timer_common_init(void)
+static int __init arch_timer_common_init(void)
 {
 	unsigned mask = ARCH_CP15_TIMER | ARCH_MEM_TIMER;
 
 	/* Wait until both nodes are probed if we have two timers */
 	if ((arch_timers_present & mask) != mask) {
 		if (arch_timer_needs_probing(ARCH_MEM_TIMER, arch_timer_mem_of_match))
-			return;
+			return 0;
 		if (arch_timer_needs_probing(ARCH_CP15_TIMER, arch_timer_of_match))
-			return;
+			return 0;
 	}
 
 	arch_timer_banner(arch_timers_present);
 	arch_counter_register(arch_timers_present);
-	arch_timer_arch_init();
+	return arch_timer_arch_init();
 }
 
-static void __init arch_timer_init(void)
+static int __init arch_timer_init(void)
 {
+	int ret;
 	/*
 	 * If HYP mode is available, we know that the physical timer
 	 * has been configured to be accessible from PL1. Use it, so
@@ -739,23 +740,30 @@ static void __init arch_timer_init(void)
 
 		if (!has_ppi) {
 			pr_warn("arch_timer: No interrupt available, giving up\n");
-			return;
+			return -EINVAL;
 		}
 	}
 
-	arch_timer_register();
-	arch_timer_common_init();
+	ret = arch_timer_register();
+	if (ret)
+		return ret;
+
+	ret = arch_timer_common_init();
+	if (ret)
+		return ret;
 
 	arch_timer_kvm_info.virtual_irq = arch_timer_ppi[VIRT_PPI];
+	
+	return 0;
 }
 
-static void __init arch_timer_of_init(struct device_node *np)
+static int __init arch_timer_of_init(struct device_node *np)
 {
 	int i;
 
 	if (arch_timers_present & ARCH_CP15_TIMER) {
 		pr_warn("arch_timer: multiple nodes in dt, skipping\n");
-		return;
+		return 0;
 	}
 
 	arch_timers_present |= ARCH_CP15_TIMER;
@@ -774,23 +782,23 @@ static void __init arch_timer_of_init(struct device_node *np)
 	    of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
 		arch_timer_uses_ppi = PHYS_SECURE_PPI;
 
-	arch_timer_init();
+	return arch_timer_init();
 }
-CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
-CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);
+CLOCKSOURCE_OF_DECLARE_RET(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
+CLOCKSOURCE_OF_DECLARE_RET(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);
 
-static void __init arch_timer_mem_init(struct device_node *np)
+static int __init arch_timer_mem_init(struct device_node *np)
 {
 	struct device_node *frame, *best_frame = NULL;
 	void __iomem *cntctlbase, *base;
-	unsigned int irq;
+	unsigned int irq, ret = -EINVAL;
 	u32 cnttidr;
 
 	arch_timers_present |= ARCH_MEM_TIMER;
 	cntctlbase = of_iomap(np, 0);
 	if (!cntctlbase) {
 		pr_err("arch_timer: Can't find CNTCTLBase\n");
-		return;
+		return -ENXIO;
 	}
 
 	cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
@@ -830,6 +838,7 @@ static void __init arch_timer_mem_init(struct device_node *np)
 		best_frame = of_node_get(frame);
 	}
 
+	ret= -ENXIO;
 	base = arch_counter_base = of_iomap(best_frame, 0);
 	if (!base) {
 		pr_err("arch_timer: Can't map frame's registers\n");
@@ -841,6 +850,7 @@ static void __init arch_timer_mem_init(struct device_node *np)
 	else
 		irq = irq_of_parse_and_map(best_frame, 0);
 
+	ret = -EINVAL;
 	if (!irq) {
 		pr_err("arch_timer: Frame missing %s irq",
 		       arch_timer_mem_use_virtual ? "virt" : "phys");
@@ -848,13 +858,17 @@ static void __init arch_timer_mem_init(struct device_node *np)
 	}
 
 	arch_timer_detect_rate(base, np);
-	arch_timer_mem_register(base, irq);
-	arch_timer_common_init();
+	ret = arch_timer_mem_register(base, irq);
+	if (ret)
+		goto out;
+
+	return arch_timer_common_init();
 out:
 	iounmap(cntctlbase);
 	of_node_put(best_frame);
+	return ret;
 }
-CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
+CLOCKSOURCE_OF_DECLARE_RET(armv7_arch_timer_mem, "arm,armv7-timer-mem",
 		       arch_timer_mem_init);
 
 #ifdef CONFIG_ACPI