linux-kernel - [PATCH AUTOSEL 5.2 018/123] MIPS: kernel: only use i8253 clocksource with periodic clockevent

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Message-Id: <20190814021047.14828-18-sashal@kernel.org>
Date:   Tue, 13 Aug 2019 22:09:02 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Thomas Bogendoerfer <tbogendoerfer@...e.de>,
        Paul Burton <paul.burton@...s.com>,
        Ralf Baechle <ralf@...ux-mips.org>,
        James Hogan <jhogan@...nel.org>, linux-mips@...r.kernel.org,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 5.2 018/123] MIPS: kernel: only use i8253 clocksource with periodic clockevent

From: Thomas Bogendoerfer <tbogendoerfer@...e.de>

[ Upstream commit a07e3324538a989b7cdbf2c679be6a7f9df2544f ]

i8253 clocksource needs a free running timer. This could only
be used, if i8253 clockevent is set up as periodic.

Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@...e.de>
Signed-off-by: Paul Burton <paul.burton@...s.com>
Cc: Ralf Baechle <ralf@...ux-mips.org>
Cc: James Hogan <jhogan@...nel.org>
Cc: linux-mips@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/mips/kernel/i8253.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kernel/i8253.c b/arch/mips/kernel/i8253.c
index 5f209f111e59e..df7ddd246eaac 100644
--- a/arch/mips/kernel/i8253.c
+++ b/arch/mips/kernel/i8253.c
@@ -32,7 +32,8 @@ void __init setup_pit_timer(void)
 
 static int __init init_pit_clocksource(void)
 {
-	if (num_possible_cpus() > 1) /* PIT does not scale! */
+	if (num_possible_cpus() > 1 || /* PIT does not scale! */
+	    !clockevent_state_periodic(&i8253_clockevent))
 		return 0;
 
 	return clocksource_i8253_init();
-- 
2.20.1