From ce9570657d45d6387a68d7f419fe70d085200a2f Mon Sep 17 00:00:00 2001
From: Fengquan Chen <Fengquan.Chen@mediatek.com>
Date: Fri, 9 Apr 2021 17:22:42 +0800
Subject: [PATCH] clocksource/drivers/mediatek: Optimize systimer irq clear
 flow on shutdown
Git-commit: ce9570657d45d6387a68d7f419fe70d085200a2f
References: git-fixes
Patch-mainline: v5.15-rc1

mtk_syst_clkevt_shutdown is called after irq disabled in suspend flow,
clear any pending systimer irq when shutdown to avoid suspend aborted
due to timer irq pending

Also as for systimer in mediatek socs, there must be firstly enable
timer before clear systimer irq

Fixes: e3af677607d9("clocksource/drivers/timer-mediatek: Add support for system timer")
Signed-off-by: Fengquan Chen <fengquan.chen@mediatek.com>
Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/1617960162-1988-2-git-send-email-Fengquan.Chen@mediatek.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/clocksource/timer-mediatek.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
index ab63b95e414f..7bcb4a3f26fb 100644
--- a/drivers/clocksource/timer-mediatek.c
+++ b/drivers/clocksource/timer-mediatek.c
@@ -60,9 +60,9 @@
  * SYST_CON_EN: Clock enable. Shall be set to
  *   - Start timer countdown.
  *   - Allow timeout ticks being updated.
- *   - Allow changing interrupt functions.
+ *   - Allow changing interrupt status,like clear irq pending.
  *
- * SYST_CON_IRQ_EN: Set to allow interrupt.
+ * SYST_CON_IRQ_EN: Set to enable interrupt.
  *
  * SYST_CON_IRQ_CLR: Set to clear interrupt.
  */
@@ -75,6 +75,7 @@ static void __iomem *gpt_sched_reg __read_mostly;
 static void mtk_syst_ack_irq(struct timer_of *to)
 {
 	/* Clear and disable interrupt */
+	writel(SYST_CON_EN, SYST_CON_REG(to));
 	writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
 }
 
@@ -111,6 +112,9 @@ static int mtk_syst_clkevt_next_event(unsigned long ticks,
 
 static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
 {
+	/* Clear any irq */
+	mtk_syst_ack_irq(to_timer_of(clkevt));
+
 	/* Disable timer */
 	writel(0, SYST_CON_REG(to_timer_of(clkevt)));
 
-- 
2.40.0