Merge tag 'timers-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master

Pull timer fix from Ingo Molnar:
 "Fix a suspend/resume regression (crash) on TI AM3/AM4 SoC's"

* tag 'timers-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/drivers/timer-ti-dm: Fix suspend and resume for am3 and am4

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
index 4f513fa3362f..191c97b84715 100644
--- a/drivers/bus/ti-sysc.c
+++ b/drivers/bus/ti-sysc.c
@@ -2865,6 +2865,24 @@ 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 */ },
@@ -2921,6 +2939,10 @@ 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;