Re: [PATCH] [v4, 1/1] clocksource/drivers/timer-mediatek: optimize systimer irq clear flow on shutdown
From: Hsin-Yi Wang <hidden>
Date: 2021-04-16 10:48:08
Also in:
linux-mediatek, lkml
On Fri, Apr 9, 2021 at 5:22 PM Fengquan Chen [off-list ref] wrote:
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 <redacted>Tested-by: Hsin-Yi Wang <redacted> Tested on a mt8183 device. This patch solves an issue that device would hang on resume during genpd_resume_noirq: [ 724.342834] mtk-smi-larb 17010000.larb: genpd_resume_noirq+0x0/0xd0 returned 0 after 976593 usecs [ 724.351721] mtk-smi-larb 1a001000.larb: calling genpd_resume_noirq+0x0/0xd0 @ 6629, parent: soc [ 736.845047] Kernel panic - not syncing: Watchdog detected hard LOCKUP on cpu 3 [ 736.852268] CPU: 2 PID: 0 Comm: swapper/2 Tainted: G W 5.10.26 #17 [ 736.859743] Hardware name: MediaTek krane sku176 board (DT) [ 736.865309] Call trace: [ 736.867756] dump_backtrace+0x0/0x1bc [ 736.871415] show_stack+0x20/0x2c [ 736.874728] dump_stack+0xc0/0x11c [ 736.878124] panic+0x174/0x378 [ 736.881178] watchdog_check_hardlockup+0x11c/0x124 [ 736.885963] watchdog_timer_fn+0x70/0x274 <snip>
quoted hunk ↗ jump to hunk
--- 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 9318edc..6461fd3 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 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))); --1.8.1.1.dirty
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