clocksource/drivers/ux500: Drop Ux500 custom SCHED_CLOCK

The two drivers used for Ux500 sched_clock use two Kconfig
symbols to select which of the two gets used as sched_clock.

This isn't right: the workaround is trying to make sure that
the NONSTOP timer is used for sched_clock in order to keep
that clock ticking consistently over a suspend/resume
cycle. (Otherwise sched_clock simply stops during suspend
and continues after resume).

This will notably affect any timetstamped debug prints,
so that they show the absolute number of seconds since the
system was booted and does not loose wall-clock time during
suspend and resume as if time stood still.

The real way to fix this problem is to make sched_clock
take advantage of any NONSTOP clock source on the system
and adjust accordingly, not to try to work around this by
using a different sched_clock depending on what system
we are compiling for. This can solve the problem for
everyone instead of providing a local solution.

Cc: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

1 files changed, 0 insertions, 18 deletions

diff --git a/drivers/clocksource/clksrc-dbx500-prcmu.c b/drivers/clocksource/clksrc-dbx500-prcmu.c
index 4054539fe066..51d53c4e646f 100644
--- a/drivers/clocksource/clksrc-dbx500-prcmu.c
+++ b/drivers/clocksource/clksrc-dbx500-prcmu.c
@@ -15,7 +15,6 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/clockchips.h>
-#include <linux/sched_clock.h>
 
 #define RATE_32K		32768
 
@@ -26,8 +25,6 @@
 #define PRCMU_TIMER_DOWNCOUNT	0x4
 #define PRCMU_TIMER_MODE	0x8
 
-#define SCHED_CLOCK_MIN_WRAP 131072 /* 2^32 / 32768 */
-
 static void __iomem *clksrc_dbx500_timer_base;
 
 static u64 notrace clksrc_dbx500_prcmu_read(struct clocksource *cs)
@@ -52,18 +49,6 @@ static struct clocksource clocksource_dbx500_prcmu = {
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_SUSPEND_NONSTOP,
 };
 
-#ifdef CONFIG_CLKSRC_DBX500_PRCMU_SCHED_CLOCK
-
-static u64 notrace dbx500_prcmu_sched_clock_read(void)
-{
-	if (unlikely(!clksrc_dbx500_timer_base))
-		return 0;
-
-	return clksrc_dbx500_prcmu_read(&clocksource_dbx500_prcmu);
-}
-
-#endif
-
 static int __init clksrc_dbx500_prcmu_init(struct device_node *node)
 {
 	clksrc_dbx500_timer_base = of_iomap(node, 0);
@@ -81,9 +66,6 @@ static int __init clksrc_dbx500_prcmu_init(struct device_node *node)
 		writel(TIMER_DOWNCOUNT_VAL,
 		       clksrc_dbx500_timer_base + PRCMU_TIMER_REF);
 	}
-#ifdef CONFIG_CLKSRC_DBX500_PRCMU_SCHED_CLOCK
-	sched_clock_register(dbx500_prcmu_sched_clock_read, 32, RATE_32K);
-#endif
 	return clocksource_register_hz(&clocksource_dbx500_prcmu, RATE_32K);
 }
 TIMER_OF_DECLARE(dbx500_prcmu, "stericsson,db8500-prcmu-timer-4",