2022-07-25 09:30:43

by Victor Hassan

[permalink] [raw]
Subject: [PATCH 1/2] clocksource: sun4i: Fix the bug that tick_resume stucks

Currently syscore_resume() will stuck on tick_resume().
Fix this by changing `.tick_resume` from
sun4i_clkevt_shutdown() to a new function sun4i_tick_resume().

Signed-off-by: Victor Hassan <[email protected]>
---
drivers/clocksource/timer-sun4i.c | 131 ++++++++++++++++++++++--------
1 file changed, 96 insertions(+), 35 deletions(-)

diff --git a/drivers/clocksource/timer-sun4i.c b/drivers/clocksource/timer-sun4i.c
index bb6ea6c19829..afc26de963af 100644
--- a/drivers/clocksource/timer-sun4i.c
+++ b/drivers/clocksource/timer-sun4i.c
@@ -38,6 +38,19 @@

#define TIMER_SYNC_TICKS 3

+/* Registers which needs to be saved and restored before and after sleeping */
+static u32 sun4i_timer_regs_offset[] = {
+ TIMER_IRQ_EN_REG,
+ TIMER_CTL_REG(0),
+ TIMER_INTVAL_REG(0),
+ TIMER_CNTVAL_REG(0),
+ TIMER_CTL_REG(1),
+ TIMER_INTVAL_REG(1),
+ TIMER_CNTVAL_REG(1),
+};
+
+static void __iomem *sun4i_timer_sched_base __read_mostly;
+
/*
* When we disable a timer, we need to wait at least for 2 cycles of
* the timer source clock. We will use for that the clocksource timer
@@ -79,10 +92,41 @@ static void sun4i_clkevt_time_start(void __iomem *base, u8 timer,
base + TIMER_CTL_REG(timer));
}

+static inline void sun4i_timer_save_regs(struct timer_of *to)
+{
+ void __iomem *base = timer_of_base(to);
+ int i;
+ u32 *regs_backup = (u32 *)to->private_data;
+
+ for (i = 0; i < ARRAY_SIZE(sun4i_timer_regs_offset); i++)
+ regs_backup[i] = readl(base + sun4i_timer_regs_offset[i]);
+}
+
+static inline void sun4i_timer_restore_regs(struct timer_of *to)
+{
+ void __iomem *base = timer_of_base(to);
+ int i;
+ u32 *regs_backup = (u32 *)to->private_data;
+
+ for (i = 0; i < ARRAY_SIZE(sun4i_timer_regs_offset); i++)
+ writel(regs_backup[i], base + sun4i_timer_regs_offset[i]);
+}
+
static int sun4i_clkevt_shutdown(struct clock_event_device *evt)
{
struct timer_of *to = to_timer_of(evt);

+ sun4i_timer_save_regs(to);
+ sun4i_clkevt_time_stop(timer_of_base(to), 0);
+
+ return 0;
+}
+
+static int sun4i_tick_resume(struct clock_event_device *evt)
+{
+ struct timer_of *to = to_timer_of(evt);
+
+ sun4i_timer_restore_regs(to);
sun4i_clkevt_time_stop(timer_of_base(to), 0);

return 0;
@@ -137,45 +181,54 @@ static irqreturn_t sun4i_timer_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}

-static struct timer_of to = {
- .flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE,
-
- .clkevt = {
- .name = "sun4i_tick",
- .rating = 350,
- .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
- .set_state_shutdown = sun4i_clkevt_shutdown,
- .set_state_periodic = sun4i_clkevt_set_periodic,
- .set_state_oneshot = sun4i_clkevt_set_oneshot,
- .tick_resume = sun4i_clkevt_shutdown,
- .set_next_event = sun4i_clkevt_next_event,
- .cpumask = cpu_possible_mask,
- },
-
- .of_irq = {
- .handler = sun4i_timer_interrupt,
- .flags = IRQF_TIMER | IRQF_IRQPOLL,
- },
-};
+static void __init sun4i_clockevent_init(struct timer_of *to)
+{
+ to->clkevt.name = "sun4i_tick";
+ to->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+ to->clkevt.set_state_shutdown = sun4i_clkevt_shutdown;
+ to->clkevt.set_state_periodic = sun4i_clkevt_set_periodic;
+ to->clkevt.set_state_oneshot = sun4i_clkevt_set_oneshot;
+ to->clkevt.tick_resume = sun4i_tick_resume;
+ to->clkevt.set_next_event = sun4i_clkevt_next_event;
+ to->clkevt.cpumask = cpu_possible_mask;
+ to->of_irq.flags = IRQF_TIMER | IRQF_IRQPOLL;
+
+ sun4i_timer_sched_base = timer_of_base(to) + TIMER_CNTVAL_REG(1);
+}

static u64 notrace sun4i_timer_sched_read(void)
{
- return ~readl(timer_of_base(&to) + TIMER_CNTVAL_REG(1));
+ return (u64)~readl(sun4i_timer_sched_base);
}

static int __init sun4i_timer_init(struct device_node *node)
{
+ struct timer_of *to;
int ret;
u32 val;

- ret = timer_of_init(node, &to);
+ to = kzalloc(sizeof(*to), GFP_KERNEL);
+ if (!to)
+ return -ENOMEM;
+
+ to->flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE;
+ to->of_irq.handler = sun4i_timer_interrupt;
+ ret = timer_of_init(node, to);
if (ret)
- return ret;
+ goto err;

- writel(~0, timer_of_base(&to) + TIMER_INTVAL_REG(1));
+ sun4i_clockevent_init(to);
+
+ to->private_data = kcalloc(ARRAY_SIZE(sun4i_timer_regs_offset), sizeof(u32), GFP_KERNEL);
+ if (!to->private_data) {
+ ret = -ENOMEM;
+ goto err1;
+ }
+
+ writel(~0, timer_of_base(to) + TIMER_INTVAL_REG(1));
writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD |
TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),
- timer_of_base(&to) + TIMER_CTL_REG(1));
+ timer_of_base(to) + TIMER_CTL_REG(1));

/*
* sched_clock_register does not have priorities, and on sun6i and
@@ -186,32 +239,40 @@ static int __init sun4i_timer_init(struct device_node *node)
of_machine_is_compatible("allwinner,sun5i-a10s") ||
of_machine_is_compatible("allwinner,suniv-f1c100s"))
sched_clock_register(sun4i_timer_sched_read, 32,
- timer_of_rate(&to));
+ timer_of_rate(to));

- ret = clocksource_mmio_init(timer_of_base(&to) + TIMER_CNTVAL_REG(1),
- node->name, timer_of_rate(&to), 350, 32,
+ ret = clocksource_mmio_init(timer_of_base(to) + TIMER_CNTVAL_REG(1),
+ node->name, timer_of_rate(to), 350, 32,
clocksource_mmio_readl_down);
if (ret) {
pr_err("Failed to register clocksource\n");
- return ret;
+ goto err2;
}

writel(TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),
- timer_of_base(&to) + TIMER_CTL_REG(0));
+ timer_of_base(to) + TIMER_CTL_REG(0));

/* Make sure timer is stopped before playing with interrupts */
- sun4i_clkevt_time_stop(timer_of_base(&to), 0);
+ sun4i_clkevt_time_stop(timer_of_base(to), 0);

/* clear timer0 interrupt */
- sun4i_timer_clear_interrupt(timer_of_base(&to));
+ sun4i_timer_clear_interrupt(timer_of_base(to));

- clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
+ clockevents_config_and_register(&to->clkevt, timer_of_rate(to),
TIMER_SYNC_TICKS, 0xffffffff);

/* Enable timer0 interrupt */
- val = readl(timer_of_base(&to) + TIMER_IRQ_EN_REG);
- writel(val | TIMER_IRQ_EN(0), timer_of_base(&to) + TIMER_IRQ_EN_REG);
+ val = readl(timer_of_base(to) + TIMER_IRQ_EN_REG);
+ writel(val | TIMER_IRQ_EN(0), timer_of_base(to) + TIMER_IRQ_EN_REG);
+
+ return ret;

+err2:
+ kfree(to->private_data);
+err1:
+ timer_of_cleanup(to);
+err:
+ kfree(to);
return ret;
}
TIMER_OF_DECLARE(sun4i, "allwinner,sun4i-a10-timer",
--
2.29.0