Commit-ID: f5ef02bd0e8cf53472cc358a542121366add0c9a
Gitweb: https://git.kernel.org/tip/f5ef02bd0e8cf53472cc358a542121366add0c9a
Author: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
AuthorDate: Mon, 8 Jan 2018 14:28:57 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 8 Jan 2018 17:57:26 +0100
clocksource/drivers/stm32: Add clocksource functionality
The scene is set for the clocksource functionality, let's add it for this driver.
Tested-by: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Acked-by: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
Cc: Alexandre Torgue <alexandre.torgue@xxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1515418139-23276-18-git-send-email-daniel.lezcano@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
drivers/clocksource/timer-stm32.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/drivers/clocksource/timer-stm32.c b/drivers/clocksource/timer-stm32.c
index 0d37f1a..21b7492 100644
--- a/drivers/clocksource/timer-stm32.c
+++ b/drivers/clocksource/timer-stm32.c
@@ -16,6 +16,7 @@
#include <linux/of_irq.h>
#include <linux/clk.h>
#include <linux/reset.h>
+#include <linux/sched_clock.h>
#include <linux/slab.h>
#include "timer-of.h"
@@ -80,6 +81,13 @@ static int stm32_timer_of_bits_get(struct timer_of *to)
return pd->bits;
}
+static void __iomem *stm32_timer_cnt __read_mostly;
+
+static u64 notrace stm32_read_sched_clock(void)
+{
+ return readl_relaxed(stm32_timer_cnt);
+}
+
static void stm32_clock_event_disable(struct timer_of *to)
{
writel_relaxed(0, timer_of_base(to) + TIM_DIER);
@@ -204,6 +212,31 @@ static void __init stm32_timer_set_prescaler(struct timer_of *to)
to->of_clk.period = DIV_ROUND_UP(to->of_clk.rate, HZ);
}
+static int __init stm32_clocksource_init(struct timer_of *to)
+{
+ u32 bits = stm32_timer_of_bits_get(to);
+ const char *name = to->np->full_name;
+
+ /*
+ * This driver allows to register several timers and relies on
+ * the generic time framework to select the right one.
+ * However, nothing allows to do the same for the
+ * sched_clock. We are not interested in a sched_clock for the
+ * 16-bit timers but only for the 32-bit one, so if no 32-bit
+ * timer is registered yet, we select this 32-bit timer as a
+ * sched_clock.
+ */
+ if (bits == 32 && !stm32_timer_cnt) {
+ stm32_timer_cnt = timer_of_base(to) + TIM_CNT;
+ sched_clock_register(stm32_read_sched_clock, bits, timer_of_rate(to));
+ pr_info("%s: STM32 sched_clock registered\n", name);
+ }
+
+ return clocksource_mmio_init(timer_of_base(to) + TIM_CNT, name,
+ timer_of_rate(to), bits == 32 ? 250 : 100,
+ bits, clocksource_mmio_readl_up);
+}
+
static void __init stm32_clockevent_init(struct timer_of *to)
{
u32 bits = stm32_timer_of_bits_get(to);
@@ -256,6 +289,10 @@ static int __init stm32_timer_init(struct device_node *node)
stm32_timer_set_prescaler(to);
+ ret = stm32_clocksource_init(to);
+ if (ret)
+ goto deinit;
+
stm32_clockevent_init(to);
return 0;
--
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