[PATCH AUTOSEL 4.14 048/115] powerpc/time: Use clockevents_register_device(), fixing an issue with large decrementer

Sasha Levin
2019-11-13T01:57:38Z

From: Anton Blanchard <anton@ozlabs.org>

[ Upstream commit 8b78fdb045de60a4eb35460092bbd3cffa925353 ]

We currently cap the decrementer clockevent at 4 seconds, even on systems
with large decrementer support. Fix this by converting the code to use
clockevents_register_device() which calculates the upper bound based on
the max_delta passed in.

Signed-off-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kernel/time.c | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index fe6f3a2854557..870e75d304591 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -984,10 +984,10 @@ static void register_decrementer_clockevent(int cpu)
*dec = decrementer_clockevent;
dec->cpumask = cpumask_of(cpu);

+ clockevents_config_and_register(dec, ppc_tb_freq, 2, decrementer_max);
+
printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
dec->name, dec->mult, dec->shift, cpu);
-
- clockevents_register_device(dec);
}

static void enable_large_decrementer(void)
@@ -1035,18 +1035,7 @@ static void __init set_decrementer_max(void)

static void __init init_decrementer_clockevent(void)
{
- int cpu = smp_processor_id();
-
- clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4);
-
- decrementer_clockevent.max_delta_ns =
- clockevent_delta2ns(decrementer_max, &decrementer_clockevent);
- decrementer_clockevent.max_delta_ticks = decrementer_max;
- decrementer_clockevent.min_delta_ns =
- clockevent_delta2ns(2, &decrementer_clockevent);
- decrementer_clockevent.min_delta_ticks = 2;
-
- register_decrementer_clockevent(cpu);
+ register_decrementer_clockevent(smp_processor_id());
}

void secondary_cpu_time_init(void)
--
2.20.1