clocksource/drivers/microblaze: 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>

arch/microblaze/kernel/timer.c

@@ -170,7 +170,7 @@ static struct irqaction timer_irqaction = {
 	.dev_id = &clockevent_xilinx_timer,
 };
 
-static __init void xilinx_clockevent_init(void)
+static __init int xilinx_clockevent_init(void)
 {
 	clockevent_xilinx_timer.mult =
 		div_sc(timer_clock_freq, NSEC_PER_SEC,
@@ -181,6 +181,8 @@ static __init void xilinx_clockevent_init(void)
 		clockevent_delta2ns(1, &clockevent_xilinx_timer);
 	clockevent_xilinx_timer.cpumask = cpumask_of(0);
 	clockevents_register_device(&clockevent_xilinx_timer);
+
+	return 0;
 }
 
 static u64 xilinx_clock_read(void)
@@ -229,8 +231,14 @@ static struct clocksource clocksource_microblaze = {
 
 static int __init xilinx_clocksource_init(void)
 {
-	if (clocksource_register_hz(&clocksource_microblaze, timer_clock_freq))
-		panic("failed to register clocksource");
+	int ret;
+
+	ret = clocksource_register_hz(&clocksource_microblaze,
+				      timer_clock_freq);
+	if (ret) {
+		pr_err("failed to register clocksource");
+		return ret;
+	}
 
 	/* stop timer1 */
 	write_fn(read_fn(timer_baseaddr + TCSR1) & ~TCSR_ENT,
@@ -239,16 +247,16 @@ static int __init xilinx_clocksource_init(void)
 	write_fn(TCSR_TINT|TCSR_ENT|TCSR_ARHT, timer_baseaddr + TCSR1);
 
 	/* register timecounter - for ftrace support */
-	init_xilinx_timecounter();
-	return 0;
+	return init_xilinx_timecounter();
 }
 
-static void __init xilinx_timer_init(struct device_node *timer)
+static int __init xilinx_timer_init(struct device_node *timer)
 {
 	struct clk *clk;
 	static int initialized;
 	u32 irq;
 	u32 timer_num = 1;
+	int ret;
 
 	if (initialized)
 		return;
@@ -258,7 +266,7 @@ static void __init xilinx_timer_init(struct device_node *timer)
 	timer_baseaddr = of_iomap(timer, 0);
 	if (!timer_baseaddr) {
 		pr_err("ERROR: invalid timer base address\n");
-		BUG();
+		return -ENXIO;
 	}
 
 	write_fn = timer_write32;
@@ -271,11 +279,15 @@ static void __init xilinx_timer_init(struct device_node *timer)
 	}
 
 	irq = irq_of_parse_and_map(timer, 0);
+	if (irq <= 0) {
+		pr_err("Failed to parse and map irq");
+		return -EINVAL;
+	}
 
 	of_property_read_u32(timer, "xlnx,one-timer-only", &timer_num);
 	if (timer_num) {
-		pr_emerg("Please enable two timers in HW\n");
-		BUG();
+		pr_err("Please enable two timers in HW\n");
+		return -EINVAL;
 	}
 
 	pr_info("%s: irq=%d\n", timer->full_name, irq);
@@ -297,15 +309,28 @@ static void __init xilinx_timer_init(struct device_node *timer)
 
 	freq_div_hz = timer_clock_freq / HZ;
 
-	setup_irq(irq, &timer_irqaction);
+	ret = setup_irq(irq, &timer_irqaction);
+	if (ret) {
+		pr_err("Failed to setup IRQ");
+		return ret;
+	}
+
 #ifdef CONFIG_HEART_BEAT
 	microblaze_setup_heartbeat();
 #endif
-	xilinx_clocksource_init();
-	xilinx_clockevent_init();
+
+	ret = xilinx_clocksource_init();
+	if (ret)
+		return ret;
+
+	ret = xilinx_clockevent_init();
+	if (ret)
+		return ret;
 
 	sched_clock_register(xilinx_clock_read, 32, timer_clock_freq);
+
+	return 0;
 }
 
-CLOCKSOURCE_OF_DECLARE(xilinx_timer, "xlnx,xps-timer-1.00.a",
+CLOCKSOURCE_OF_DECLARE_RET(xilinx_timer, "xlnx,xps-timer-1.00.a",
 		       xilinx_timer_init);