Commit 67948ada authored by Stanislav Meduna's avatar Stanislav Meduna Committed by Shawn Guo

ARM: mxs: Setup scheduler clock

Setup scheduler clock on ARM MXS platforms with a 32-bit timrot
such as i.MX28. This allows the scheduler to use sub-jiffy resolution.

The corresponding change for 16-bit v1 timrots is not possible
at the moment due to rounding issues with clock values wrapping
faster than once per several seconds in the common ARM platform code.
Signed-off-by: default avatarStanislav Meduna <stano@meduna.org>
Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>
parent 24196d5c
...@@ -29,6 +29,7 @@ ...@@ -29,6 +29,7 @@
#include <linux/of_irq.h> #include <linux/of_irq.h>
#include <asm/mach/time.h> #include <asm/mach/time.h>
#include <asm/sched_clock.h>
#include <mach/mxs.h> #include <mach/mxs.h>
#include <mach/common.h> #include <mach/common.h>
...@@ -233,15 +234,22 @@ static struct clocksource clocksource_mxs = { ...@@ -233,15 +234,22 @@ static struct clocksource clocksource_mxs = {
.flags = CLOCK_SOURCE_IS_CONTINUOUS, .flags = CLOCK_SOURCE_IS_CONTINUOUS,
}; };
static u32 notrace mxs_read_sched_clock_v2(void)
{
return ~readl_relaxed(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1));
}
static int __init mxs_clocksource_init(struct clk *timer_clk) static int __init mxs_clocksource_init(struct clk *timer_clk)
{ {
unsigned int c = clk_get_rate(timer_clk); unsigned int c = clk_get_rate(timer_clk);
if (timrot_is_v1()) if (timrot_is_v1())
clocksource_register_hz(&clocksource_mxs, c); clocksource_register_hz(&clocksource_mxs, c);
else else {
clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1), clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1),
"mxs_timer", c, 200, 32, clocksource_mmio_readl_down); "mxs_timer", c, 200, 32, clocksource_mmio_readl_down);
setup_sched_clock(mxs_read_sched_clock_v2, 32, c);
}
return 0; return 0;
} }
......
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