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Date: Tue, 12 Dec 2017 13:47:00 +0800
From: Rick Chen <rickchen36@...il.com>
To: rickchen36@...il.com, rick@...estech.com,
linux-kernel@...r.kernel.org, arnd@...db.de,
linus.walleij@...aro.org, daniel.lezcano@...aro.org,
linux-arch@...r.kernel.org, tglx@...utronix.de,
jason@...edaemon.net, marc.zyngier@....com, robh+dt@...nel.org,
netdev@...r.kernel.org, deanbo422@...il.com,
devicetree@...r.kernel.org, viro@...iv.linux.org.uk,
dhowells@...hat.com, will.deacon@....com,
linux-serial@...r.kernel.org
Cc: Vincent Chen <vincentc@...estech.com>,
Greentime Hu <green.hu@...il.com>
Subject: [PATCH v5 2/3] clocksource/drivers/atcpit100: VDSO support
VDSO needs real-time cycle count to ensure the time accuracy.
Unlike others, nds32 architecture does not define clock source,
hence VDSO needs atcpit100 offering real-time cycle count
to derive the correct time.
Signed-off-by: Vincent Chen <vincentc@...estech.com>
Signed-off-by: Rick Chen <rickchen36@...il.com>
Signed-off-by: Greentime Hu <green.hu@...il.com>
---
drivers/clocksource/timer-atcpit100.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/clocksource/timer-atcpit100.c b/drivers/clocksource/timer-atcpit100.c
index 0077fdb..1be6c0a 100644
--- a/drivers/clocksource/timer-atcpit100.c
+++ b/drivers/clocksource/timer-atcpit100.c
@@ -29,6 +29,9 @@
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include "timer-of.h"
+#ifdef CONFIG_NDS32
+#include <asm/vdso_timer_info.h>
+#endif
/*
* Definition of register offsets
@@ -211,6 +214,14 @@ static u64 notrace atcpit100_timer_sched_read(void)
return ~readl(timer_of_base(&to) + CH1_CNT);
}
+#ifdef CONFIG_NDS32
+static void fill_vdso_need_info(void)
+{
+ timer_info.cycle_count_down = true;
+ timer_info.cycle_count_reg_offset = CH1_CNT;
+}
+#endif
+
static int __init atcpit100_timer_init(struct device_node *node)
{
int ret;
@@ -249,6 +260,10 @@ static int __init atcpit100_timer_init(struct device_node *node)
val = readl(base + INT_EN);
writel(val | CH0INT0EN, base + INT_EN);
+#ifdef CONFIG_NDS32
+ fill_vdso_need_info();
+#endif
+
return ret;
}
--
2.7.4
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