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clocksource/drivers/davinci: Add support for clocksource

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Extend the davinci-timer driver to also register a clock source.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This commit is contained in:
Bartosz Golaszewski 2019-06-24 11:50:56 +02:00 committed by Daniel Lezcano
parent 721154f972
commit b0c74b96d1
1 changed files with 85 additions and 0 deletions
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85
drivers/clocksource/timer-davinci.c
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@ -43,6 +43,8 @@
#define DAVINCI_TIMER_MIN_DELTA 0x01
#define DAVINCI_TIMER_MAX_DELTA 0xfffffffe
#define DAVINCI_TIMER_CLKSRC_BITS 32
#define DAVINCI_TIMER_TGCR_DEFAULT \
(DAVINCI_TIMER_TIMMODE_32BIT_UNCHAINED | DAVINCI_TIMER_UNRESET)
@ -52,6 +54,16 @@ struct davinci_clockevent {
unsigned int cmp_off;
};
/*
* This must be globally accessible by davinci_timer_read_sched_clock(), so
* let's keep it here.
*/
static struct {
struct clocksource dev;
void __iomem *base;
unsigned int tim_off;
} davinci_clocksource;
static struct davinci_clockevent *
to_davinci_clockevent(struct clock_event_device *clockevent)
{
@ -166,6 +178,53 @@ static irqreturn_t davinci_timer_irq_timer(int irq, void *data)
return IRQ_HANDLED;
}
static u64 notrace davinci_timer_read_sched_clock(void)
{
return readl_relaxed(davinci_clocksource.base +
davinci_clocksource.tim_off);
}
static u64 davinci_clocksource_read(struct clocksource *dev)
{
return davinci_timer_read_sched_clock();
}
/*
* Standard use-case: we're using tim12 for clockevent and tim34 for
* clocksource. The default is making the former run in oneshot mode
* and the latter in periodic mode.
*/
static void davinci_clocksource_init_tim34(void __iomem *base)
{
int tcr;
tcr = DAVINCI_TIMER_ENAMODE_PERIODIC <<
DAVINCI_TIMER_ENAMODE_SHIFT_TIM34;
tcr |= DAVINCI_TIMER_ENAMODE_ONESHOT <<
DAVINCI_TIMER_ENAMODE_SHIFT_TIM12;
writel_relaxed(0x0, base + DAVINCI_TIMER_REG_TIM34);
writel_relaxed(UINT_MAX, base + DAVINCI_TIMER_REG_PRD34);
writel_relaxed(tcr, base + DAVINCI_TIMER_REG_TCR);
}
/*
* Special use-case on da830: the DSP may use tim34. We're using tim12 for
* both clocksource and clockevent. We set tim12 to periodic and don't touch
* tim34.
*/
static void davinci_clocksource_init_tim12(void __iomem *base)
{
unsigned int tcr;
tcr = DAVINCI_TIMER_ENAMODE_PERIODIC <<
DAVINCI_TIMER_ENAMODE_SHIFT_TIM12;
writel_relaxed(0x0, base + DAVINCI_TIMER_REG_TIM12);
writel_relaxed(UINT_MAX, base + DAVINCI_TIMER_REG_PRD12);
writel_relaxed(tcr, base + DAVINCI_TIMER_REG_TCR);
}
static void davinci_timer_init(void __iomem *base)
{
/* Set clock to internal mode and disable it. */
@ -247,6 +306,32 @@ int __init davinci_timer_register(struct clk *clk,
DAVINCI_TIMER_MIN_DELTA,
DAVINCI_TIMER_MAX_DELTA);
davinci_clocksource.dev.rating = 300;
davinci_clocksource.dev.read = davinci_clocksource_read;
davinci_clocksource.dev.mask =
CLOCKSOURCE_MASK(DAVINCI_TIMER_CLKSRC_BITS);
davinci_clocksource.dev.flags = CLOCK_SOURCE_IS_CONTINUOUS;
davinci_clocksource.base = base;
if (timer_cfg->cmp_off) {
davinci_clocksource.dev.name = "tim12";
davinci_clocksource.tim_off = DAVINCI_TIMER_REG_TIM12;
davinci_clocksource_init_tim12(base);
} else {
davinci_clocksource.dev.name = "tim34";
davinci_clocksource.tim_off = DAVINCI_TIMER_REG_TIM34;
davinci_clocksource_init_tim34(base);
}
rv = clocksource_register_hz(&davinci_clocksource.dev, tick_rate);
if (rv) {
pr_err("Unable to register clocksource");
return rv;
}
sched_clock_register(davinci_timer_read_sched_clock,
DAVINCI_TIMER_CLKSRC_BITS, tick_rate);
return 0;
}