[PATCH v2 2/3] ARM: lib32: pbl: implement get_time_ns and is_timeout

[Stefan Kerkmann <s.kerkmann@pengutronix.de>]

ARMv7-A cores can implement the optional 64bit wide generic timer
CNTPCT[1]. If it is present we can use it to implement the get_time_ns
and is_timeout helpers which in turn enable the whole read_poll_timeout
class of functions in the PBL. As it is guaranteed that the timer won't
wrap for 40 years no overflow handling is necessary.

[1]: See "ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition
(rev C.d)", Chapter B8 "The Generic Timer"

Signed-off-by: Stefan Kerkmann <s.kerkmann@pengutronix.de>
---
 arch/arm/lib32/arm_architected_timer.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm/lib32/arm_architected_timer.c b/arch/arm/lib32/arm_architected_timer.c
index 54eca13f8b..75f74cbc15 100644
--- a/arch/arm/lib32/arm_architected_timer.c
+++ b/arch/arm/lib32/arm_architected_timer.c
@@ -10,8 +10,21 @@ void arm_architected_timer_udelay(unsigned long us)
 	unsigned long long ticks, cntfrq = get_cntfrq();
 	unsigned long long start = get_cntpct();
 
-	ticks = DIV_ROUND_DOWN_ULL((us * cntfrq), 1000000);
+	ticks = DIV_ROUND_DOWN_ULL((us * cntfrq), MSECOND);
 
 	while ((long)(start + ticks - get_cntpct()) > 0)
 		;
 }
+
+uint64_t get_time_ns(void)
+{
+	return get_cntpct() * SECOND / get_cntfrq();
+}
+
+int is_timeout(uint64_t start, uint64_t time_offset_ns)
+{
+	if ((int64_t)(start + time_offset_ns - get_time_ns()) < 0)
+		return 1;
+	else
+		return 0;
+}

-- 
2.47.3