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clocksource/drivers/tcb_clksrc: Use tcb as sched_clock 

Now that the driver is registered early enough, use the TCB as the
sched_clock which is much more accurate than the jiffies implementation.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This commit is contained in:
Alexandre Belloni 2019-04-26 23:47:12 +02:00 committed by Daniel Lezcano
parent 86232bfd28
commit f712a1e8e5
1 changed files with 16 additions and 0 deletions
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16
drivers/clocksource/tcb_clksrc.c
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@ -11,6 +11,7 @@
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
#include <linux/syscore_ops.h>
#include <soc/at91/atmel_tcb.h>
@ -114,6 +115,16 @@ static struct clocksource clksrc = {
.resume = tc_clksrc_resume,
};
static u64 notrace tc_sched_clock_read(void)
{
return tc_get_cycles(&clksrc);
}
static u64 notrace tc_sched_clock_read32(void)
{
return tc_get_cycles32(&clksrc);
}
#ifdef CONFIG_GENERIC_CLOCKEVENTS
struct tc_clkevt_device {
@ -335,6 +346,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
struct atmel_tc tc;
struct clk *t0_clk;
const struct of_device_id *match;
u64 (*tc_sched_clock)(void);
u32 rate, divided_rate = 0;
int best_divisor_idx = -1;
int clk32k_divisor_idx = -1;
@ -419,6 +431,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
clksrc.read = tc_get_cycles32;
/* setup ony channel 0 */
tcb_setup_single_chan(&tc, best_divisor_idx);
tc_sched_clock = tc_sched_clock_read32;
} else {
/* we have three clocks no matter what the
* underlying platform supports.
@ -430,6 +443,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
}
/* setup both channel 0 & 1 */
tcb_setup_dual_chan(&tc, best_divisor_idx);
tc_sched_clock = tc_sched_clock_read;
}
/* and away we go! */
@ -442,6 +456,8 @@ static int __init tcb_clksrc_init(struct device_node *node)
if (ret)
goto err_unregister_clksrc;
sched_clock_register(tc_sched_clock, 32, divided_rate);
return 0;
err_unregister_clksrc: