[GIT PULL] clocksource driver fix

[Ingo Molnar <mingo@kernel.org>]

Linus,

Please pull the latest timers/urgent git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers-urgent-2020-07-25

   # HEAD: b4a25fb0e62990df467451744b22e0e24960a5e6 Merge tag 'timers-v5.8-rc7' of https://git.linaro.org/people/daniel.lezcano/linux into timers/urgent

Fix a suspend/resume regression (crash) on TI AM3/AM4 SoC's.

 Thanks,

	Ingo

------------------>
Tony Lindgren (1):
      clocksource/drivers/timer-ti-dm: Fix suspend and resume for am3 and am4


 drivers/bus/ti-sysc.c                      | 22 ++++++++++++++
 drivers/clocksource/timer-ti-dm-systimer.c | 46 +++++++++++++++++++++++-------
 2 files changed, 58 insertions(+), 10 deletions(-)

diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
index bb54fb514e40..c6427d0bc94c 100644
--- a/drivers/bus/ti-sysc.c
+++ b/drivers/bus/ti-sysc.c
@@ -2864,6 +2864,24 @@ static int sysc_check_disabled_devices(struct sysc *ddata)
 	return error;
 }
 
+/*
+ * Ignore timers tagged with no-reset and no-idle. These are likely in use,
+ * for example by drivers/clocksource/timer-ti-dm-systimer.c. If more checks
+ * are needed, we could also look at the timer register configuration.
+ */
+static int sysc_check_active_timer(struct sysc *ddata)
+{
+	if (ddata->cap->type != TI_SYSC_OMAP2_TIMER &&
+	    ddata->cap->type != TI_SYSC_OMAP4_TIMER)
+		return 0;
+
+	if ((ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT) &&
+	    (ddata->cfg.quirks & SYSC_QUIRK_NO_IDLE))
+		return -EBUSY;
+
+	return 0;
+}
+
 static const struct of_device_id sysc_match_table[] = {
 	{ .compatible = "simple-bus", },
 	{ /* sentinel */ },
@@ -2920,6 +2938,10 @@ static int sysc_probe(struct platform_device *pdev)
 	if (error)
 		return error;
 
+	error = sysc_check_active_timer(ddata);
+	if (error)
+		return error;
+
 	error = sysc_get_clocks(ddata);
 	if (error)
 		return error;
diff --git a/drivers/clocksource/timer-ti-dm-systimer.c b/drivers/clocksource/timer-ti-dm-systimer.c
index 6fd1f219a512..f6fd1c1cc527 100644
--- a/drivers/clocksource/timer-ti-dm-systimer.c
+++ b/drivers/clocksource/timer-ti-dm-systimer.c
@@ -19,7 +19,7 @@
 /* For type1, set SYSC_OMAP2_CLOCKACTIVITY for fck off on idle, l4 clock on */
 #define DMTIMER_TYPE1_ENABLE	((1 << 9) | (SYSC_IDLE_SMART << 3) | \
 				 SYSC_OMAP2_ENAWAKEUP | SYSC_OMAP2_AUTOIDLE)
-
+#define DMTIMER_TYPE1_DISABLE	(SYSC_OMAP2_SOFTRESET | SYSC_OMAP2_AUTOIDLE)
 #define DMTIMER_TYPE2_ENABLE	(SYSC_IDLE_SMART_WKUP << 2)
 #define DMTIMER_RESET_WAIT	100000
 
@@ -44,6 +44,8 @@ struct dmtimer_systimer {
 	u8 ctrl;
 	u8 wakeup;
 	u8 ifctrl;
+	struct clk *fck;
+	struct clk *ick;
 	unsigned long rate;
 };
 
@@ -298,16 +300,20 @@ static void __init dmtimer_systimer_select_best(void)
 }
 
 /* Interface clocks are only available on some SoCs variants */
-static int __init dmtimer_systimer_init_clock(struct device_node *np,
+static int __init dmtimer_systimer_init_clock(struct dmtimer_systimer *t,
+					      struct device_node *np,
 					      const char *name,
 					      unsigned long *rate)
 {
 	struct clk *clock;
 	unsigned long r;
+	bool is_ick = false;
 	int error;
 
+	is_ick = !strncmp(name, "ick", 3);
+
 	clock = of_clk_get_by_name(np, name);
-	if ((PTR_ERR(clock) == -EINVAL) && !strncmp(name, "ick", 3))
+	if ((PTR_ERR(clock) == -EINVAL) && is_ick)
 		return 0;
 	else if (IS_ERR(clock))
 		return PTR_ERR(clock);
@@ -320,6 +326,11 @@ static int __init dmtimer_systimer_init_clock(struct device_node *np,
 	if (!r)
 		return -ENODEV;
 
+	if (is_ick)
+		t->ick = clock;
+	else
+		t->fck = clock;
+
 	*rate = r;
 
 	return 0;
@@ -339,7 +350,10 @@ static void dmtimer_systimer_enable(struct dmtimer_systimer *t)
 
 static void dmtimer_systimer_disable(struct dmtimer_systimer *t)
 {
-	writel_relaxed(0, t->base + t->sysc);
+	if (!dmtimer_systimer_revision1(t))
+		return;
+
+	writel_relaxed(DMTIMER_TYPE1_DISABLE, t->base + t->sysc);
 }
 
 static int __init dmtimer_systimer_setup(struct device_node *np,
@@ -366,13 +380,13 @@ static int __init dmtimer_systimer_setup(struct device_node *np,
 		pr_err("%s: clock source init failed: %i\n", __func__, error);
 
 	/* For ti-sysc, we have timer clocks at the parent module level */
-	error = dmtimer_systimer_init_clock(np->parent, "fck", &rate);
+	error = dmtimer_systimer_init_clock(t, np->parent, "fck", &rate);
 	if (error)
 		goto err_unmap;
 
 	t->rate = rate;
 
-	error = dmtimer_systimer_init_clock(np->parent, "ick", &rate);
+	error = dmtimer_systimer_init_clock(t, np->parent, "ick", &rate);
 	if (error)
 		goto err_unmap;
 
@@ -496,12 +510,18 @@ static void omap_clockevent_idle(struct clock_event_device *evt)
 	struct dmtimer_systimer *t = &clkevt->t;
 
 	dmtimer_systimer_disable(t);
+	clk_disable(t->fck);
 }
 
 static void omap_clockevent_unidle(struct clock_event_device *evt)
 {
 	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
 	struct dmtimer_systimer *t = &clkevt->t;
+	int error;
+
+	error = clk_enable(t->fck);
+	if (error)
+		pr_err("could not enable timer fck on resume: %i\n", error);
 
 	dmtimer_systimer_enable(t);
 	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_ena);
@@ -570,8 +590,8 @@ static int __init dmtimer_clockevent_init(struct device_node *np)
 					3, /* Timer internal resynch latency */
 					0xffffffff);
 
-	if (of_device_is_compatible(np, "ti,am33xx") ||
-	    of_device_is_compatible(np, "ti,am43")) {
+	if (of_machine_is_compatible("ti,am33xx") ||
+	    of_machine_is_compatible("ti,am43")) {
 		dev->suspend = omap_clockevent_idle;
 		dev->resume = omap_clockevent_unidle;
 	}
@@ -616,12 +636,18 @@ static void dmtimer_clocksource_suspend(struct clocksource *cs)
 
 	clksrc->loadval = readl_relaxed(t->base + t->counter);
 	dmtimer_systimer_disable(t);
+	clk_disable(t->fck);
 }
 
 static void dmtimer_clocksource_resume(struct clocksource *cs)
 {
 	struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
 	struct dmtimer_systimer *t = &clksrc->t;
+	int error;
+
+	error = clk_enable(t->fck);
+	if (error)
+		pr_err("could not enable timer fck on resume: %i\n", error);
 
 	dmtimer_systimer_enable(t);
 	writel_relaxed(clksrc->loadval, t->base + t->counter);
@@ -653,8 +679,8 @@ static int __init dmtimer_clocksource_init(struct device_node *np)
 	dev->mask = CLOCKSOURCE_MASK(32);
 	dev->flags = CLOCK_SOURCE_IS_CONTINUOUS;
 
-	if (of_device_is_compatible(np, "ti,am33xx") ||
-	    of_device_is_compatible(np, "ti,am43")) {
+	/* Unlike for clockevent, legacy code sets suspend only for am4 */
+	if (of_machine_is_compatible("ti,am43")) {
 		dev->suspend = dmtimer_clocksource_suspend;
 		dev->resume = dmtimer_clocksource_resume;
 	}