Some variants of the dw_apb_timer don't have an eoi register but instead expect 
a
one to be written to the int_status register at eoi time.

Signed-off-by: Ulrich Prinz <ulrich.pr...@googlemail.com>
---
 drivers/clocksource/dw_apb_timer.c |   10 +++++++++-
 include/linux/dw_apb_timer.h       |    5 +++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/dw_apb_timer.c 
b/drivers/clocksource/dw_apb_timer.c
index 5f80a30..23cd7c6 100644
--- a/drivers/clocksource/dw_apb_timer.c
+++ b/drivers/clocksource/dw_apb_timer.c
@@ -104,6 +104,11 @@ static void apbt_eoi(struct dw_apb_timer *timer)
        apbt_readl(timer, timer->reg_eoi);
 }
 
+static void apbt_eoi_int_status(struct dw_apb_timer *timer)
+{
+       apbt_writel(timer, 1, timer->reg_int_status);
+}
+
 static irqreturn_t dw_apb_clockevent_irq(int irq, void *data)
 {
        struct clock_event_device *evt = data;
@@ -286,7 +291,10 @@ dw_apb_clockevent_init(int cpu, const char *name, unsigned 
rating,
                                          IRQF_NOBALANCING |
                                          IRQF_DISABLED;
 
-       dw_ced->eoi = apbt_eoi;
+       if (quirks & APBTMR_QUIRK_NO_EOI)
+               dw_ced->eoi = apbt_eoi_int_status;
+       else
+               dw_ced->eoi = apbt_eoi;
        err = setup_irq(irq, &dw_ced->irqaction);
        if (err) {
                pr_err("failed to request timer irq\n");
diff --git a/include/linux/dw_apb_timer.h b/include/linux/dw_apb_timer.h
index 80f6686..fbe4c6b 100644
--- a/include/linux/dw_apb_timer.h
+++ b/include/linux/dw_apb_timer.h
@@ -25,6 +25,11 @@
  */
 #define APBTMR_QUIRK_64BIT_COUNTER     BIT(0)
 
+/* The IP does not provide a end-of-interrupt register to clear pending
+ * interrupts, but requires to write a 1 to the interrupt-status register.
+ */
+#define APBTMR_QUIRK_NO_EOI            BIT(1)
+
 struct dw_apb_timer {
        void __iomem                            *base;
        unsigned long                           freq;
-- 
1.7.10.4

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