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authorLinus Walleij <linus.walleij@linaro.org>2018-11-15 16:32:03 +0300
committerDaniel Lezcano <daniel.lezcano@linaro.org>2018-12-19 00:22:23 +0300
commit85b6fcadcf6626ad520376eacfb2b77090e782ab (patch)
tree5b0ef9aa8494e566f112d0201d546ac6325f7d22 /drivers
parentbc0750e464d41e1234f56471b8f626b8d945b1a8 (diff)
downloadlinux-85b6fcadcf6626ad520376eacfb2b77090e782ab.tar.xz
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/clocksource/Kconfig13
-rw-r--r--drivers/clocksource/clksrc-dbx500-prcmu.c18
-rw-r--r--drivers/clocksource/nomadik-mtu.c4
3 files changed, 0 insertions, 35 deletions
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 55c77e44bb2d..64d5759ddf0e 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -163,12 +163,6 @@ config CLKSRC_NOMADIK_MTU
to multiple interrupt generating programmable
32-bit free running decrementing counters.
-config CLKSRC_NOMADIK_MTU_SCHED_CLOCK
- bool
- depends on CLKSRC_NOMADIK_MTU
- help
- Use the Multi Timer Unit as the sched_clock.
-
config CLKSRC_DBX500_PRCMU
bool "Clocksource PRCMU Timer" if COMPILE_TEST
depends on HAS_IOMEM
@@ -226,13 +220,6 @@ config INTEGRATOR_AP_TIMER
help
Enables support for the Integrator-ap timer.
-config CLKSRC_DBX500_PRCMU_SCHED_CLOCK
- bool "Clocksource PRCMU Timer sched_clock"
- depends on (CLKSRC_DBX500_PRCMU && !CLKSRC_NOMADIK_MTU_SCHED_CLOCK)
- default y
- help
- Use the always on PRCMU Timer as sched_clock
-
config CLKSRC_EFM32
bool "Clocksource for Energy Micro's EFM32 SoCs" if !ARCH_EFM32
depends on OF && ARM && (ARCH_EFM32 || COMPILE_TEST)
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",
diff --git a/drivers/clocksource/nomadik-mtu.c b/drivers/clocksource/nomadik-mtu.c
index 8e4ddb9420c6..19b336c9b417 100644
--- a/drivers/clocksource/nomadik-mtu.c
+++ b/drivers/clocksource/nomadik-mtu.c
@@ -69,7 +69,6 @@ static u32 clk_prescale;
static u32 nmdk_cycle; /* write-once */
static struct delay_timer mtu_delay_timer;
-#ifdef CONFIG_CLKSRC_NOMADIK_MTU_SCHED_CLOCK
/*
* Override the global weak sched_clock symbol with this
* local implementation which uses the clocksource to get some
@@ -82,7 +81,6 @@ static u64 notrace nomadik_read_sched_clock(void)
return -readl(mtu_base + MTU_VAL(0));
}
-#endif
static unsigned long nmdk_timer_read_current_timer(void)
{
@@ -234,9 +232,7 @@ static int __init nmdk_timer_init(void __iomem *base, int irq,
return ret;
}
-#ifdef CONFIG_CLKSRC_NOMADIK_MTU_SCHED_CLOCK
sched_clock_register(nomadik_read_sched_clock, 32, rate);
-#endif
/* Timer 1 is used for events, register irq and clockevents */
setup_irq(irq, &nmdk_timer_irq);