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clocksource/drivers/stm32: Add clocksource functionality

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The scene is set for the clocksource functionality, let's add it for this driver.

Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-18-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Benjamin Gaignard 2018-01-08 14:28:57 +01:00 committed by Ingo Molnar
parent 3c84e75b1e
commit f5ef02bd0e
1 changed files with 37 additions and 0 deletions
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37
drivers/clocksource/timer-stm32.c
View file

@ -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;