linux-kernel - [PATCH V2 44/63] clocksource/drivers/timer-integrator-ap: Convert init function to return error

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Message-Id: <1466112442-31105-45-git-send-email-daniel.lezcano@linaro.org>
Date:	Thu, 16 Jun 2016 23:27:03 +0200
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	daniel.lezcano@...aro.org, tglx@...utronix.de
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH V2 44/63] clocksource/drivers/timer-integrator-ap: 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@...aro.org>
---
 drivers/clocksource/timer-integrator-ap.c | 59 ++++++++++++++++++++-----------
 1 file changed, 38 insertions(+), 21 deletions(-)

diff --git a/drivers/clocksource/timer-integrator-ap.c b/drivers/clocksource/timer-integrator-ap.c
index 3f59ac2..675face 100644
--- a/drivers/clocksource/timer-integrator-ap.c
+++ b/drivers/clocksource/timer-integrator-ap.c
@@ -36,11 +36,12 @@ static u64 notrace integrator_read_sched_clock(void)
 	return -readl(sched_clk_base + TIMER_VALUE);
 }
 
-static void integrator_clocksource_init(unsigned long inrate,
-					void __iomem *base)
+static int integrator_clocksource_init(unsigned long inrate,
+				       void __iomem *base)
 {
 	u32 ctrl = TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC;
 	unsigned long rate = inrate;
+	int ret;
 
 	if (rate >= 1500000) {
 		rate /= 16;
@@ -50,11 +51,15 @@ static void integrator_clocksource_init(unsigned long inrate,
 	writel(0xffff, base + TIMER_LOAD);
 	writel(ctrl, base + TIMER_CTRL);
 
-	clocksource_mmio_init(base + TIMER_VALUE, "timer2",
-			rate, 200, 16, clocksource_mmio_readl_down);
+	ret = clocksource_mmio_init(base + TIMER_VALUE, "timer2",
+				    rate, 200, 16, clocksource_mmio_readl_down);
+	if (ret)
+		return ret;
 
 	sched_clk_base = base;
 	sched_clock_register(integrator_read_sched_clock, 16, rate);
+
+	return 0;
 }
 
 static unsigned long timer_reload;
@@ -138,11 +143,12 @@ static struct irqaction integrator_timer_irq = {
 	.dev_id		= &integrator_clockevent,
 };
 
-static void integrator_clockevent_init(unsigned long inrate,
-				void __iomem *base, int irq)
+static int integrator_clockevent_init(unsigned long inrate,
+				      void __iomem *base, int irq)
 {
 	unsigned long rate = inrate;
 	unsigned int ctrl = 0;
+	int ret;
 
 	clkevt_base = base;
 	/* Calculate and program a divisor */
@@ -156,14 +162,18 @@ static void integrator_clockevent_init(unsigned long inrate,
 	timer_reload = rate / HZ;
 	writel(ctrl, clkevt_base + TIMER_CTRL);
 
-	setup_irq(irq, &integrator_timer_irq);
+	ret = setup_irq(irq, &integrator_timer_irq);
+	if (ret)
+		return ret;
+
 	clockevents_config_and_register(&integrator_clockevent,
 					rate,
 					1,
 					0xffffU);
+	return 0;
 }
 
-static void __init integrator_ap_timer_init_of(struct device_node *node)
+static int __init integrator_ap_timer_init_of(struct device_node *node)
 {
 	const char *path;
 	void __iomem *base;
@@ -176,12 +186,12 @@ static void __init integrator_ap_timer_init_of(struct device_node *node)
 
 	base = of_io_request_and_map(node, 0, "integrator-timer");
 	if (IS_ERR(base))
-		return;
+		return PTR_ERR(base);
 
 	clk = of_clk_get(node, 0);
 	if (IS_ERR(clk)) {
 		pr_err("No clock for %s\n", node->name);
-		return;
+		return PTR_ERR(clk);
 	}
 	clk_prepare_enable(clk);
 	rate = clk_get_rate(clk);
@@ -189,31 +199,38 @@ static void __init integrator_ap_timer_init_of(struct device_node *node)
 
 	err = of_property_read_string(of_aliases,
 				"arm,timer-primary", &path);
-	if (WARN_ON(err))
-		return;
+	if (err) {
+		pr_warn("Failed to read property");
+		return err;
+	}
+
 	pri_node = of_find_node_by_path(path);
+
 	err = of_property_read_string(of_aliases,
 				"arm,timer-secondary", &path);
-	if (WARN_ON(err))
-		return;
+	if (err) {
+		pr_warn("Failed to read property");		
+		return err;
+	}
+
+
 	sec_node = of_find_node_by_path(path);
 
-	if (node == pri_node) {
+	if (node == pri_node)
 		/* The primary timer lacks IRQ, use as clocksource */
-		integrator_clocksource_init(rate, base);
-		return;
-	}
+		return integrator_clocksource_init(rate, base);
 
 	if (node == sec_node) {
 		/* The secondary timer will drive the clock event */
 		irq = irq_of_parse_and_map(node, 0);
-		integrator_clockevent_init(rate, base, irq);
-		return;
+		return integrator_clockevent_init(rate, base, irq);
 	}
 
 	pr_info("Timer @%p unused\n", base);
 	clk_disable_unprepare(clk);
+
+	return 0;
 }
 
-CLOCKSOURCE_OF_DECLARE(integrator_ap_timer, "arm,integrator-timer",
+CLOCKSOURCE_OF_DECLARE_RET(integrator_ap_timer, "arm,integrator-timer",
 		       integrator_ap_timer_init_of);
-- 
1.9.1