[PATCH 6/9] clocksource: dw_apb_timer: quirk for inverted int mask

[heiko@sntech.de (Heiko Stübner)]

Some timer variants use an inverted setting to mask the timer interrupt.
Therefore add a quirk to handle these variants.

Signed-off-by: Ulrich Prinz <ulrich.prinz@googlemail.com>
---
 drivers/clocksource/dw_apb_timer.c |   23 ++++++++++++++++++-----
 include/linux/dw_apb_timer.h       |    6 ++++++
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/clocksource/dw_apb_timer.c b/drivers/clocksource/dw_apb_timer.c
index 23cd7c6..7705d13 100644
--- a/drivers/clocksource/dw_apb_timer.c
+++ b/drivers/clocksource/dw_apb_timer.c
@@ -84,7 +84,10 @@ static void apbt_disable_int(struct dw_apb_timer *timer)
 {
 	unsigned long ctrl = apbt_readl(timer, timer->reg_control);
 
-	ctrl |= APBTMR_CONTROL_INT;
+	if (timer->quirks & APBTMR_QUIRK_INVERSE_INTMASK)
+		ctrl &= ~APBTMR_CONTROL_INT;
+	else
+		ctrl |= APBTMR_CONTROL_INT;
 	apbt_writel(timer, ctrl, timer->reg_control);
 }
 
@@ -134,7 +137,10 @@ static void apbt_enable_int(struct dw_apb_clock_event_device *dw_ced)
 	/* clear pending intr */
 	if (dw_ced->eoi)
 		dw_ced->eoi(timer);
-	ctrl &= ~APBTMR_CONTROL_INT;
+	if (timer->quirks & APBTMR_QUIRK_INVERSE_INTMASK)
+		ctrl |= APBTMR_CONTROL_INT;
+	else
+		ctrl &= ~APBTMR_CONTROL_INT;
 	apbt_writel(timer, ctrl, timer->reg_control);
 }
 
@@ -195,7 +201,10 @@ static void apbt_set_mode(enum clock_event_mode mode,
 		if (timer->quirks & APBTMR_QUIRK_64BIT_COUNTER)
 			apbt_writel(timer, 0, timer->reg_load_count + 0x4);
 
-		ctrl &= ~APBTMR_CONTROL_INT;
+		if (timer->quirks & APBTMR_QUIRK_INVERSE_INTMASK)
+			ctrl |= APBTMR_CONTROL_INT;
+		else
+			ctrl &= ~APBTMR_CONTROL_INT;
 		ctrl |= APBTMR_CONTROL_ENABLE;
 		apbt_writel(timer, ctrl, timer->reg_control);
 		break;
@@ -363,9 +372,13 @@ void dw_apb_clocksource_start(struct dw_apb_clocksource *dw_cs)
 	if (timer->quirks & APBTMR_QUIRK_64BIT_COUNTER)
 		apbt_writel(timer, 0, timer->reg_load_count + 0x4);
 
-	/* enable, mask interrupt */
+	/* set periodic, mask interrupt, enable timer */
 	ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC;
-	ctrl |= (APBTMR_CONTROL_ENABLE | APBTMR_CONTROL_INT);
+	if (timer->quirks & APBTMR_QUIRK_INVERSE_INTMASK)
+		ctrl &= ~APBTMR_CONTROL_INT;
+	else
+		ctrl |= APBTMR_CONTROL_INT;
+	ctrl |= APBTMR_CONTROL_ENABLE;
 	apbt_writel(timer, ctrl, timer->reg_control);
 	/* read it once to get cached counter value initialized */
 	dw_apb_clocksource_read(dw_cs);
diff --git a/include/linux/dw_apb_timer.h b/include/linux/dw_apb_timer.h
index fbe4c6b..7d36d91 100644
--- a/include/linux/dw_apb_timer.h
+++ b/include/linux/dw_apb_timer.h
@@ -30,6 +30,12 @@
  */
 #define APBTMR_QUIRK_NO_EOI		BIT(1)
 
+/* The IP uses an inverted interrupt-mask bit.
+ * Instead of activating interrupts clearing a maks bit, it needs an enable
+ * bit to be set 1.
+ */
+#define APBTMR_QUIRK_INVERSE_INTMASK	BIT(2)
+
 struct dw_apb_timer {
 	void __iomem				*base;
 	unsigned long				freq;
-- 
1.7.10.4