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clocksource/drivers/stm32: Factor out more of the clockevent code

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In order to prepare the clocksource code, let's factor out the clockevent
code, split the prescaler and timer width code into separate functions.

Tested-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/1515418139-23276-17-git-send-email-daniel.lezcano@linaro.org
[ Small edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Daniel Lezcano 2018-01-08 14:28:56 +01:00 committed by Ingo Molnar
parent 8e82df381b
commit 3c84e75b1e
1 changed files with 82 additions and 25 deletions
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107
drivers/clocksource/timer-stm32.c
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@ -44,6 +44,42 @@
#define TIM_PSC_MAX USHRT_MAX
#define TIM_PSC_CLKRATE 10000
struct stm32_timer_private {
int bits;
};
/**
* stm32_timer_of_bits_set - set accessor helper
* @to: a timer_of structure pointer
* @bits: the number of bits (16 or 32)
*
* Accessor helper to set the number of bits in the timer-of private
* structure.
*
*/
static void stm32_timer_of_bits_set(struct timer_of *to, int bits)
{
struct stm32_timer_private *pd = to->private_data;
pd->bits = bits;
}
/**
* stm32_timer_of_bits_get - get accessor helper
* @to: a timer_of structure pointer
*
* Accessor helper to get the number of bits in the timer-of private
* structure.
*
* Returns an integer corresponding to the number of bits.
*/
static int stm32_timer_of_bits_get(struct timer_of *to)
{
struct stm32_timer_private *pd = to->private_data;
return pd->bits;
}
static void stm32_clock_event_disable(struct timer_of *to)
{
writel_relaxed(0, timer_of_base(to) + TIM_DIER);
@ -124,35 +160,31 @@ static irqreturn_t stm32_clock_event_handler(int irq, void *dev_id)
* is 32 bits wide, the result will be UINT_MAX, otherwise it will
* be truncated by the 16-bit register to USHRT_MAX.
*
* Returns UINT_MAX if the timer is 32 bits wide, USHRT_MAX if it is a
* 16 bits wide.
*/
static u32 __init stm32_timer_width(struct timer_of *to)
static void __init stm32_timer_set_width(struct timer_of *to)
{
u32 width;
writel_relaxed(UINT_MAX, timer_of_base(to) + TIM_ARR);
return readl_relaxed(timer_of_base(to) + TIM_ARR);
width = readl_relaxed(timer_of_base(to) + TIM_ARR);
stm32_timer_of_bits_set(to, width == UINT_MAX ? 32 : 16);
}
static void __init stm32_clockevent_init(struct timer_of *to)
/**
* stm32_timer_set_prescaler - Compute and set the prescaler register
* @to: a pointer to a timer-of structure
*
* Depending on the timer width, compute the prescaler to always
* target a 10MHz timer rate for 16 bits. 32-bit timers are
* considered precise and long enough to not use the prescaler.
*/
static void __init stm32_timer_set_prescaler(struct timer_of *to)
{
u32 width = 0;
int prescaler;
int prescaler = 1;
to->clkevt.name = to->np->full_name;
to->clkevt.features = CLOCK_EVT_FEAT_PERIODIC;
to->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
to->clkevt.set_state_shutdown = stm32_clock_event_shutdown;
to->clkevt.set_state_periodic = stm32_clock_event_set_periodic;
to->clkevt.set_state_oneshot = stm32_clock_event_set_oneshot;
to->clkevt.tick_resume = stm32_clock_event_shutdown;
to->clkevt.set_next_event = stm32_clock_event_set_next_event;
width = stm32_timer_width(to);
if (width == UINT_MAX) {
prescaler = 1;
to->clkevt.rating = 250;
} else {
if (stm32_timer_of_bits_get(to) != 32) {
prescaler = DIV_ROUND_CLOSEST(timer_of_rate(to),
TIM_PSC_CLKRATE);
/*
@ -161,7 +193,6 @@ static void __init stm32_clockevent_init(struct timer_of *to)
* this case.
*/
prescaler = prescaler < TIM_PSC_MAX ? prescaler : TIM_PSC_MAX;
to->clkevt.rating = 100;
}
writel_relaxed(prescaler - 1, timer_of_base(to) + TIM_PSC);
@ -171,12 +202,26 @@ static void __init stm32_clockevent_init(struct timer_of *to)
/* Adjust rate and period given the prescaler value */
to->of_clk.rate = DIV_ROUND_CLOSEST(to->of_clk.rate, prescaler);
to->of_clk.period = DIV_ROUND_UP(to->of_clk.rate, HZ);
}
clockevents_config_and_register(&to->clkevt,
timer_of_rate(to), 0x1, width);
static void __init stm32_clockevent_init(struct timer_of *to)
{
u32 bits = stm32_timer_of_bits_get(to);
to->clkevt.name = to->np->full_name;
to->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
to->clkevt.set_state_shutdown = stm32_clock_event_shutdown;
to->clkevt.set_state_periodic = stm32_clock_event_set_periodic;
to->clkevt.set_state_oneshot = stm32_clock_event_set_oneshot;
to->clkevt.tick_resume = stm32_clock_event_shutdown;
to->clkevt.set_next_event = stm32_clock_event_set_next_event;
to->clkevt.rating = bits == 32 ? 250 : 100;
clockevents_config_and_register(&to->clkevt, timer_of_rate(to), 0x1,
(1 << bits) - 1);
pr_info("%pOF: STM32 clockevent driver initialized (%d bits)\n",
to->np, width == UINT_MAX ? 32 : 16);
to->np, bits);
}
static int __init stm32_timer_init(struct device_node *node)
@ -196,14 +241,26 @@ static int __init stm32_timer_init(struct device_node *node)
if (ret)
goto err;
to->private_data = kzalloc(sizeof(struct stm32_timer_private),
GFP_KERNEL);
if (!to->private_data)
goto deinit;
rstc = of_reset_control_get(node, NULL);
if (!IS_ERR(rstc)) {
reset_control_assert(rstc);
reset_control_deassert(rstc);
}
stm32_timer_set_width(to);
stm32_timer_set_prescaler(to);
stm32_clockevent_init(to);
return 0;
deinit:
timer_of_cleanup(to);
err:
kfree(to);
return ret;