linux-kernel - [PATCH v20 09/17] clocksource/drivers/arm_arch_timer: Refactor arch_timer_needs

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Date:   Wed, 18 Jan 2017 21:25:33 +0800
From:   fu.wei@...aro.org
To:     rjw@...ysocki.net, lenb@...nel.org, daniel.lezcano@...aro.org,
        tglx@...utronix.de, marc.zyngier@....com, mark.rutland@....com,
        lorenzo.pieralisi@....com, sudeep.holla@....com,
        hanjun.guo@...aro.org
Cc:     linux-arm-kernel@...ts.infradead.org, linaro-acpi@...ts.linaro.org,
        linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
        rruigrok@...eaurora.org, harba@...eaurora.org, cov@...eaurora.org,
        timur@...eaurora.org, graeme.gregory@...aro.org,
        al.stone@...aro.org, jcm@...hat.com, wei@...hat.com, arnd@...db.de,
        catalin.marinas@....com, will.deacon@....com,
        Suravee.Suthikulpanit@....com, leo.duran@....com, wim@...ana.be,
        linux@...ck-us.net, linux-watchdog@...r.kernel.org,
        tn@...ihalf.com, christoffer.dall@...aro.org, julien.grall@....com,
        Fu Wei <fu.wei@...aro.org>
Subject: [PATCH v20 09/17] clocksource/drivers/arm_arch_timer: Refactor arch_timer_needs_probing

From: Fu Wei <fu.wei@...aro.org>

When system init with device-tree, we don't know which node will be
initialized first. And the code in arch_timer_common_init should wait
until per-cpu timer and MMIO timer are both initialized. So we need
arch_timer_needs_probing to detect the init status of system.

But currently the code is dispersed in arch_timer_needs_probing and
arch_timer_common_init. And the function name doesn't specify that
it's only for device-tree. This is somewhat confusing.

This patch move all related code from arch_timer_common_init to
arch_timer_needs_probing, refactor it, and rename it to
arch_timer_needs_of_probing. And make sure that it will be called
only if acpi is disabled.

Signed-off-by: Fu Wei <fu.wei@...aro.org>
---
 drivers/clocksource/arm_arch_timer.c | 34 +++++++++++++++++++---------------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 9482481..d10c2f7 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -796,15 +796,28 @@ static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
 	{},
 };
 
-static bool __init
-arch_timer_needs_probing(int type, const struct of_device_id *matches)
+static bool __init arch_timer_needs_of_probing(void)
 {
 	struct device_node *dn;
 	bool needs_probing = false;
+	unsigned int mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM;
 
-	dn = of_find_matching_node(NULL, matches);
-	if (dn && of_device_is_available(dn) && !(arch_timers_present & type))
+	/* We have two timers, and both device-tree nodes are probed. */
+	if ((arch_timers_present & mask) == mask)
+		return false;
+
+	/*
+	 * Only one type of timer is probed,
+	 * check if we have another type of timer node in device-tree.
+	 */
+	if (arch_timers_present & ARCH_TIMER_TYPE_CP15)
+		dn = of_find_matching_node(NULL, arch_timer_mem_of_match);
+	else
+		dn = of_find_matching_node(NULL, arch_timer_of_match);
+
+	if (dn && of_device_is_available(dn))
 		needs_probing = true;
+
 	of_node_put(dn);
 
 	return needs_probing;
@@ -812,17 +825,8 @@ arch_timer_needs_probing(int type, const struct of_device_id *matches)
 
 static int __init arch_timer_common_init(void)
 {
-	unsigned mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM;
-
-	/* Wait until both nodes are probed if we have two timers */
-	if ((arch_timers_present & mask) != mask) {
-		if (arch_timer_needs_probing(ARCH_TIMER_TYPE_MEM,
-					     arch_timer_mem_of_match))
-			return 0;
-		if (arch_timer_needs_probing(ARCH_TIMER_TYPE_CP15,
-					     arch_timer_of_match))
-			return 0;
-	}
+	if (acpi_disabled && arch_timer_needs_of_probing())
+		return 0;
 
 	arch_timer_banner(arch_timers_present);
 	arch_counter_register(arch_timers_present);
-- 
2.9.3