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[53/71] clocksource: arm_global_timer: Only check for unusable timer on A9

Message ID 1400841111-6683-53-git-send-email-daniel.lezcano@linaro.org
State Accepted
Commit 2cf2ff9f1fcdca404885bc55292b2046eabc039a
Headers show

Commit Message

Daniel Lezcano May 23, 2014, 10:31 a.m. UTC 
From: Matthew Leach <matthew.leach@arm.com>

The check for a usable global timer in the probe code does not enquire
which CPU we are currently running on. This can cause the driver to
incorrectly assume we have an unusable global timer if we are running
on a CPU other than A9.

Before checking the CPU revision, ensure we are running on an A9 CPU.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/arm_global_timer.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c
index 0fc31d0..60e5a170 100644
--- a/drivers/clocksource/arm_global_timer.c
+++ b/drivers/clocksource/arm_global_timer.c
@@ -246,11 +246,12 @@  static void __init global_timer_of_register(struct device_node *np)
 	int err = 0;
 
 	/*
-	 * In r2p0 the comparators for each processor with the global timer
+	 * In A9 r2p0 the comparators for each processor with the global timer
 	 * fire when the timer value is greater than or equal to. In previous
 	 * revisions the comparators fired when the timer value was equal to.
 	 */
-	if ((read_cpuid_id() & 0xf0000f) < 0x200000) {
+	if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9
+	    && (read_cpuid_id() & 0xf0000f) < 0x200000) {
 		pr_warn("global-timer: non support for this cpu version.\n");
 		return;
 	}